05/067540

08/21/1973

08/27/1970

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De Laval Turbine Inc. (Oakland, CA)

417/1

417/274, 417/18

F17D1/14; F17D1/00; F04B49/02

417/1,12,18,33,44,45,274,275,276,277

3232519

Compressor protection system

February 1966

Long

Croyle, Carlton R.

Sher R. J.

What is claimed is

1. An automatic control system for an engine driving a gas compressor having a compression pocket and adapted to be connected in a pipeline comprising means for isolating said pocket from the remaining compression volume of said compressor, a step-by-step programmer, means for generating pneumatic pulses, means responsive to a control factor for regulating said pulse generating means, means responsive to said pulses for stepping and positioning said programmer, and pnuematic means responsive to the position of said programmer for operating said pocket isolating means, and means for controlling the operation of said engine, and pneumatic means responsive to the position of said programmer for operating said engine controlling means.

2. An automatic control system for an engine driving a gas compressor having a compression pocket and adapted to be connected in a pipeline comprising means for isolating said pocket from the remaining compression volume of said compressor, a step-by-step programmer, means for generating pneumatic pulses, means responsive to a control factor for regulating said pulse generating means, means responsive to said pulses for stepping and positioning said programmer, and pneumatic means responsive to the position of said programmer for operating said pocket isolating means, and means substantially responsive to the brake mean effective pressure of said engine, and pneumatic means controlled by said brake mean effective pressure responsive means for stepping said programmer to control said engine.

3. An automatic control system for an engine driving a gas compressor having a compression pocket and adapted to be connected in a pipeline comprising means for isolating said pocket from the remaining compression volume of said compressor, a step-by-step programmer, means for generating pneumatic pulses, means responsive to a control factor for regulating said pulse generating means, means responsive to said pulses for stepping and positioning said programmer, and pneumatic means responsive to the position of said programmer for operating said pocket isolating means, and a pneumatically actuated vibration shut-down device responsive to excessive engine vibration, and means controlled by said programmer for temporarily disabling said vibration shut-down device.

4. An automatic control system for an engine driven gas compressor and including a pneumatic control board incorporating a pneumatic duct extending between an entrance port and an exit port, a pneumatic means for stopping said engine, means connecting said exit port to said pneumatic means, a pneumatically actuated engine shut-down device responsive to an operating factor of said engine, means connecting said shut-down device to actuate said stopping means, and means controlled by said engine shut-down device for venting to atmosphere the supply of pneumatic fluid at said entrance port.

The pumping of fluids, particularly fuel gas through long pipelines, is often accomplished by engine-driven compressors installed at stations arranged along the pipeline at appropriate intervals and often constructed so that the individual stations can be connected into the pipeline or excluded therefrom from time to time. The pumping load often varies for this reason and for other reasons such as the changing demand for or supply of gas. It has been customary to provide such pumping stations with an attendant crew to start, supervise and stop the operation of the engine and compressor and to include or exclude the compressor in or from the transmission line as well as to perform the customary supervision and the usual maintance. In a fuel gas pumping operation, the danger of fire is always present and must be given fundamental consideration since often the staions are remote from ready help. In recent years the size and capacity of such stations has increased, so that disability or malfunctioning for any reason is very serious.

It is therefore an object of my invention to provide an automatic control system for an engine and compressor unit adapted to be installed in a gas pumping line in which various degrees of automatic operation may be selected.

Another object of the invention is to provide such a system responsive to control from a remote point or locally.

A further object of the invention is to provide an automatic control system largely using pneumatic elements to reduce hazard from the use of electrical elements.

An additional object of the invention is to provide an automatic control system especially responsive to pneumatic characteristics.

A further object of the invention is to provide an automatic control system of relative simplicity and effective to respond to numerous environmental anoperational characteristics.

An additional object of the invention is to provide an automatic control system of acceptable durability and reliability, one that is easily maintained and repaired, one teat is economical in relation to its work, and one that can readily be adapted to engines and compressors of accepted or standard design.

Another object of the invention is to provide a generally improved automatic control system useable in many different installations and with various kinds of machinery but especially effective in an engine-compressor-pipeline installation.

Other objects of the invention together with the foregoing are attained in the embodiment of the invention described in the accompanying description and illustrated in the accompanying drawings, in which:

FIG. 1 is a diagrammatic layout of Sheets 1-13 inclusive;

FIG. 2 consists of Sheets 1-13 inclusive arranged according to the layout illustrated in FIG. 1 and showing diagrammatically mechanisms, air circuits and logic boards of the automatic control system of the invention;

FIG. 3 consists of Sheets A-F inclusive arranged as indicated thereon and when so arranged illustrating the functioning or sequence of operations of the various parts of the control system of the invention;

FIGS. 4-11 inclusive are diagrammatic showings of pneumatic logic elements appearing in the control system, the individual figures being as follows

FIG. 4 illustrates an or-gate,

FIG. 5 illustrates an and-gate,

FIG. 6 illustrates a not-gate,

FIG. 7 illustrates a timing element,

FIG. 8 illustrates a memory unit,

FIG. 9 illustrates a set-reset unit,

FIG. 10 illustrates a differentiator, and

FIG. 11 illustrates an accumulator;

FIGS. 12-40 inclusive are diagrammatic showings of pneumatic circuit boards used in the control system, as follows:

FIG. 12 illustrates Board A -- Shut-down Pressurizer,

FIG. 13 illustrates Board B -- Shut-down Timed Lock-out,

FIG. 14 illustrates Board C -- Suction Valve Control,

FIG. 15 illustrates Board D -- Discharge Valve Control,

FIG. 16 illustrates Board E -- Blow-down Valve Control,

FIG. 17 illustrates Board F -- Bypass Valve Control,

FIG. 18 illustrates Board G -- Upshift To Position 2,

FIG. 19 illustrates Board H -- Latched Stop Input-Output,

FIG. 20 illustrates Board I -- Reset Pulser,

FIG. 21 illustrates Board J -- Downshift-Speed Interlock,

FIG. 22 illustrates Board K -- Pulse Conditioner,

FIG. 23 illustrates Board L -- Upshift To Position 3 and 4,

From 24 illustrates Board M -- places. Conditioner, in

FIG. 25 illustrates Board N -- Permissive Input No. 2,

FIG. 26 illustrates Board O -- Cranking Timer,

FIG. 27 illustrates Board P -- Permissive Input No. 1,

FIG. 28 illustrates Board Q -- Run-Gas AND Dead Engine,

FIG. 29 illustrates Board R -- Pulser Pressurizer,

FIG. 30 illustrates Board S -- Ignition And Gas Valve Latch,

FIG. 31 illustrates Board T -- Suction And Bypass Valve Control,

FIG. 32 illustrates Board U -- BMEP And Differential Pressure Interlock,

FIG. 33 illustrates Board V --]Upshift-Speed Inertlock,

FIG. 34 illustrates Board W -- Raise-lower Pulser,

FIG. 35 illustrates Board X -- Speed Control,

FIG. 36 illustrates Board Y -- Latched Stop,

FIG. 37 Billustrates Board Z -- High BMEP - High Differential Pressure Shut-down Selector,

FIG. 38 illustrates Board AA -- Downshift To Position 3,

FIG. 39 illustrates Board BB -- Vibration Lock-out, and

FIG. 40 illustrates Board CC -- Downshift To Position 2 And 1;

FIG. 41 is a diagrammatic showing of the programmer positions and of active cams;

FIG. 42 is a plot of the mode selector cam effects; and

FIG. 43 is a plot of the single point start control cam effects.

In order to follow the sequence of events which are controlled pursuant to the invention, reference is had to Sheets A-F of FIG. 3, which depict in diagrammatic form the various events chosen for this particular example and which can be varied from time to time or from installation to installation in order to arrive at the desired end result in as nearly an automatic fashion as desired.

The installation described is one in which the gas-fueled internal combustion engine is mechanically coupled to a gas compressor. The compressor cylinders are provided both at the head end and at the crank end with volume pockets that can be opened to the cylinder to increase the volume thereof or segregated from the cylinder in order to reduce the compression volume or clearance volume thereof. The compressor itself is connected into a pipeline by means of various valves that are individually controllable. As shown in FIG. 2, Sheet 1, the valves include a suction valve, a purge valve, a bypass valve, a blow-down valve and a discharge valve.

As a convenient, exemplary cycle of operation, it can be considered that all of the mechanism is in condition for operation and that the beginning of the operation is responsive to an apppropriate signal, which can be manually initiated or can be automatically initiated. In any case, there is an initial impulse which is represented by the start signal event 101, and the start impulse is immediately effective to produce a latched start event 102. This latch event is simply the automatic maintenance of an input or start signal until such signal is later on automatically released, despite the fact that the initial impulse or manual motion may have theretofore been discontinued.

The latched start event is effective to produce a reset event 103 on a mechanical programming device, usually referred to as a programmer. This structure is as diagrammatically shown in FIG. 2, Sheets 11 and 12, and generally includes a cam drum having a plurality of individually adjustable cams thereon and rotatable in either direction by step increments through a series of positions as diagrammed in FIG. 41, so that of an arbitrary number of cams; for example, 12, all can be moved into any one of a total of 16 positions by the operation of the stepping mechanism. Thus, the first effect of the latched start event 102 is to provide an event 103 or series of events in the programmer to reset the programmer into Position 1, should it be out of that position. As indicated by FIG. 41, Position 1 is a position in which only cam 12 is effective upon a control instrumentality such as an air valve or gas valve.

At the start, the programmer usually is already in Position 1 and so requires no resetting, but it is possible that service operations, repairs or he like may have left the programmer in some other position. To ensure that the start in appropriate, the latched start event 102 immediately produces the reset event 103 to make certain that the programmer is in Position 1 with only cam 12 effective. The presence of cam 12 in starting position is illustrated by the indicated event 104 in FIG. 3. The makeup of the programmer is such, as will later appear in the detailed description thereof, that when cam 12 is in starting Position 1, cam 1 is not effective. This is not only shown by the diagram but likewise is shown by the event 106, in which the vinculum or bar indicates that cam 1 is not effective or is out of active position.

Upon the occurrence of the three events; that is, the reset event 103, the absence of cam 1 from effective position pursuant to event 106, and the presence of cam 12 in Position 1 pursuant to event 104, then a symbolic and-gate 107, having all three impulses concurrently available, is effective to produce a program shift event 108, in which an impulse to the programmer advances the programmer one step into Position 2. This shift provides an event 105 unlatching the start event 102. In this position, cam 12 remains active and cam 1 becomes active. The change in programmer position from event 103, Position 1, to event 108, Position 2, is utilized through the programmer control mechanism to arrange the gas line valves, as shown in FIG. 3, is that: the blow-down valve is moved from opened position into closed position; the bypass valve, being already in opened position, remains in opened position; and the suction and discharge valves, being in closed position, remain in closed position.

With this condition of the line valves, the shift event 108 to Position 2 is followed by a purge event 109 pursuant to which the purge valve is opened for a predetermined period of time and then is permitted to close upon expiration of that time. The purge valve is a normally closed valve urged closed by some resilient means such as a spring, and the timed purge event 109 is effectuated by overcoming the spring closure for a selected interval, a typical time being about 25 seconds. At the conclusion of the timed purged event 109, the next occurrence is to close the blow-down valve in an event 111. That is, this event 111 shifts the blow-down valve into closed position, as indicated in the drawing FIG. 3, and when the blow-down valve arrives in closed position a verification signal is sent out and is appropriately received and is then effective as one of the seven factors imposed upon a symbolic and-gate event 112.

Another factor involved in conditioning the and-gate event 112 is that the discharge valve is in closed position, Another factor indicated by the event 113. Anothefactor controlling the and-gate event 112 is that the programmer is in fact in its Position 2, in which cam 1 is effective, as confirmed by the event 114. That the bypass valve is actually in opened position is confirmed by event 116 effective upon the and-gate event 112. Various operating conditions of the engine and compressor, such as the temperature of the lubricant, the appropriate temperature of the cooling water, the supply of fuel, and other similar operating characteristics, are all considered together as Group I factors. All of these factors must be satisfactorily present in order to permit the initial operation of the rotating machinery.

Each of the factors in Group I has its own signal, and these signals are accumulated to give an event 117 indicating that all of the Group I shut-down factors are armed; that is, presently satisfactory for operation and instantly available for engine and compressor shut-down in the event there should be a failure of any one of the factors. The Group I shut-down event 117 is effective upon the and-gate event 112. Also, there is a verification that the suction valve is in fact closed, and this is an event 118, necessarily present for functioning of the and-gate event 112. Finally, there is a detector to indicate whether or not the engine is in its stationary, stopped or "dead" position. In order not injure the starting mechanism, it is deemed important that the engine not already be running from some previous control when the starting cycle is initiated. Therefore, there is a dead engine event 119 likewise effective upon the and-gate event 112.

When all seven signals are simultaneously available for the and-gate event 112, then permission is given to advance to the next event. This is a latched crank signal for the engine. This event 121 means simply that the cranking mechanism of the engine, including the engine starting mechanism, is energized and is energized for a predetermined period of time. The latched starting event is provided so that the starting cycle, once initiated, continues until a subsequent signal unlatches the cranking signal. The effect of the latched crank event 121 is to energize the starting motor or motors so that the crank-engine event 122 occurs, and the engine and its coupled compressor are mechanically rotated although at this time the engine is not under its own power. Also, the latched crank event 121 affords a pneumatic, pulse generator event 123; that is, there is initiated a train or series of successive, pneumatic pulses, each of which is effective to produce a counting event 124, so that after a predetermined number of pneumatic pulses from the pulse generator event 123 has been accumulated, then there is initiated an ignition latched-on event 126.

At this time the engine is mechanically rotating and the ignition has been furnished and is maintained in its on condition. After the initiation of the event 126 there is interposed a time delay event 127 simply as a precautionary measure to make sure that all of the various operating instrumentalities have had an opportunity to assume their steady state effects. After the expiration of the time delay event 127, which in a normal case is from two to three seconds, and impulse is given to an ignition and-gate event 128. No signal passes the and-gate event 128, however, until the that and-gate event also and simultaneously receives the results of a proof-of-ignition event 129. This is the output of a mechanism that "sees" the electric spark occurring in the engine cylinders so that there is assurance that ignition of effective nature is actually present within the combustion chambers.

When the ignition and-gate event 128 has both of its input impulses from the events 127 and 129, it issues a signal to a starting gas on event 131. This means that a small supply of the running fuel, which in this case is natural gas, is fed to the engine combustion chambers. This can be accomplished by opening a small bleed in a gas line valve connected to the engine. The rotating engine, having been supplied with an ignition spark and with starting gas, should commence power operation. If there is no combustion, the engine will not rotate in excess of its cranking speed, but when the engine does start by combustion of the supplied gas then the engine speed increases to its idle speed. As soon as the engine reaches idle speed, an idle speed event 132 is effective to send out a signal to an unlatch crank event 133. This in turn sends back a signal through an or-gate event 130 to the latched crank event 121 and unlatches the cranking motor event so that the cranking motors disengage and no longer furnish any impulse to rotate the main engine.

The up-to-idle-speed event 132 furnishes a signal to a run-gas-on event 134 effectuating an increase in the gas supply to the engine sufficient so that the engine can by its own effort increase its speed from the starting gas idling speed up to the governed speed. The engine is provided with the customary speed governor which so manipulates the gas supply to the engine that the engine normally operates at a predetermined, set or governed speed. When the engine has increased its operation from idle to the governed speed, as indicated by the event 136, then a signal goes into a speed and-gate event 137. The other input to the and-gate event 137 is a verification from the programmer that in fact cam 2, as indicated by the event 138, is not effective and that cams 1 and 12 are the only ones effective, thus verifying that the programmer is still in Position 2.

When the and-gate event 137 has the two inputs simultaneously from the events 136 and 138, then it provides for a shift to Position 3, event 138, and the programmer advances one step to Position 3, in which cams 1, 2 and 12 are effective. In Position 3, according to the event 138, the end result is that the blow-down valve is closed, the bypass valve is opened, the suction valve is closed, and the discharge valve is opened. The event 138 issues a signal to establish an open purge valve event 139. This opens the purge valve so that there can be a pressure equalization in the compressor loop to bring the compressor loop up to the minimum selected suction pressure as indicated by the event 141.

Upon the attainment of the minimum suction pressure in the compressor loop, there follows an event 142, which is to close the purge valve and to leave the loop otherwise undisturbed. When the purge valve is closed, a signal goes to make sure that the discharge valve, according to Position 3, is opened, and a verification signal thereof is represented by the event 143. This signal affords an impulse to an and-gate event 144. Another impulse for the and-gate 144 comes from a verification that the programmer is truly in Position 3 by reason of the fact that cam 3 is not effective. The absence of cam 3 is an event 146 furnished to the and-gate 144.

Since the engine by now has been operating under its own power for some time, it is important to check the lubricating oil temperature. When the lubricating oil has achieved its minimum, normal operating temperature of approximately 100°, this event 147 is noted and is made effective also upon the and-gate event 144. When the events 143, 146 and 147 are simultaneously present for the and-gate event 144, then a signal goes to effectuate a shift to Position 4 of the mechanical programmer, being indicated by an event 148. In Position 4 the blow-down valve remains closed, the bypass valve is moved from opened to closed, the suction valve is moved from closed to opened, and the discharge valve remains opened. This in effect is the last event to put the compressor on the gas line for pumping. While the shift to Position 4 finally results in the valves promptly attaining the positions just mentioned, it is preferred that the bypass valve, although eventually to be closed, at first does so only partially or moves only at a deliberate pace. Thus, when the event 148, the shift to Position 4, occurs, it likewise furnishes a signal to an event 149, which starts to close the bypass valve but does so only partway at a very slow speed.

Also from the event 148, a signal carries over to an and-gate event 151 and furnishes one of the two impulses therefor. At this state of operation there is preferably provided a sensing of the differential pressure measured across the suction valve to make sure that such differential pressure is within acceptable limits, and this event 152 is likewise effective, when an appropriate differential pressure has been attained across the suction valve, to afford a signal to provide for halting the closing motion of the bypass valve in an appropriate intermediate position pursuant to an event 153. The suction valve and the bypass valve are mutually interoperated so that the bypass valve is closed at a rate or is moved to a partly closed position so as to provide an acceptable differential pressure across the suction valve.

When there has been a signal indicating that the differential pressure across the suction valve is at an appropriate value, then the signal goes to the and-gate event 151 and, with the signal from the event 148, affords a signal to open the suction valve and to verify the fact that it is open, and this is an event 154. Then, when the suction valve is fully open and there has been verification of that fact, there is a signal that produces a succeeding event 156. This is a full closure of the bypass valve and a verification signal that such valve is in fact in closed position. Upon verification of the closure of the bypass valve pursuant to event 156, there is introduced a moderate time delay, an event 157, merely as a precautionary step to assure that the system, particularly in the compressor loop, has attained a non-surging steady state condition.

The compressor at this time is fully on the line and is operating to pump gas from the suction side to the discharge side. After a suitable short time delay to ensure balancing of these events, then there is a control signal sent to the discharge pressure set point controller according to an event 158. The discharge pressure is accurately controlled to attain as nearly as possible a predetermined value, usually measured in a certain number of pounds per square inch, and the discharge pressure set controller has the effect of responding to the discharge pressure and to put out signals in the event the discharge pressure is too low in order to raise such pressure, or to put out signals to lower such pressure in the event the discharge pressure is too high.

If, for example, it should occur that from the event 158 there is a signal that the discharge pressure is inordinately low and should be raised, then a raise pulse is made effective upon a raise and-gate event 161. Before there can be any action to raise the compressor discharge pressure, however, the and-gate event 161 must be satisfied that certain other critical conditions are appropriate. Thus there is an event 162 which indicates that there is not an excessively high differential pressure existing between the compressor suction and the compressor discharge. Since the compressor is made for a certain pressure increase, if for any reason there should be an excessive pressure across the compressor so that further attempts to raise such pressure might be mechanically disastrous to the compressor, no raising signal ensues. But should the differential pressure across the compressor be within a satisfactory range; that is, should there be an absence of a high differential pressure, then the event 162 affords a signal to the and-gate event 161.

In a quite similar fashion, there is a mechanism to measure the brake means effective pressure of the engine. Engine design dicates that the brake means effective pressure not exceed a selected value. In the absence of an excessive brake means effective pressure, that event 163 sends an impulse to the and-gate event 161. The presence of the raise signal from the event 158, the "absence of high differential pressure" signal from the event 162, and the "absence of high brake means effective pressure" signal from the event 163, all actuate the and-gate event 161 to issue a raise signal to a load adjust pulser event 164.

The load adjust pulser is a mechanism which converts analog information input to digital information output and when actuated furnishes one or more timed pulses either effective in the raising direction when a load raising signal comes in, or effective to send out one or more lowering signals when a load lowering signal comes in. In any event, when the raise signal impressed upon the load adjust pulser event 164, then a raise pulse or raise pulses are discharged therefrom and may be effective in various different ways. The prime purpose of the raise pulses from the event 164 is to boost the engine-compressor output. If the programmer has already upshifted through several steps so that both cams 7 and 11 are in active position, which is event 166, then the compressor is correspondingly in its volumetrically most effective position, or. if the BMEP is or, low, event 167, then either event 166 or event 167 is effective through an or-gate 168 to afford a signal to a raise-speed event 169. The raise-speed event 169 is that in which the governor permits the engine to operate under controlled conditions at the maximum predetermined speed. That is, the raise-speed event 169 conditions the governor so that the engine is not inhibited from reaching its maximum governed speed.

However, it is considered better operating procedure and it is preferred, before increasing the engine speed and if the brake mean effective pressure is low and there must be an adjustment of the load in an increasing fashion, first to decrease the compressor clearance volume to its minimum operating or design value. Thus, if the compressor clearance volume is still relatively large, then there should be no speed increase. Consequently, if theere is a low brake mean effective pressure condition according to an event 171, a signal goes to an and-gate event 172. This and-gate is not effective until it is given another input. If cams 7 and 11 are not effective, an event 173, that means that the programmer has not fully upshifted and that the compressor volume is not yet fully diminished. This ineffectiveness of cams 7 and 11, an event 173, passes part of the raise signal to the and-gate event 172. Thus, the and-gate is so enabled to issue a signal which first verifies that there is no downshift event 174 simultaneously occurring.

In the absence of such a downshift signal, the and-gate 172 event effectually signals a progressive upshift event 175. This event affects the programmer to make one upshift in position for each pulse received. If the load adjust pulser event 164 simply sends out one raise pulse, then eventually the upshift event 175 advances the programmer one step only. However, should there be two of three pulses or more from the load adjust pulser event 164, then the programmer upshifts in a correspnding number of stations or positions. Now, as appears elsewhere, the shifting of the programmer conditions the compressor to vary the output of the compressor by changing its pocket configuration, so that an effect of the load adjust pulser is eventually to adjust or condition the compressor so that the engine load is appropriate. The raise events tend to close the compressor pockets successively, so that the output pressure of the compressor and its load increase. This occurs until cams 7 and 11 come into effectiveness, all pockets are closed, and the compressor clearance volume is a minimum. Any upshift pulses thereafter serve only to increase the engine speed, as described above.

Reverting to the discharge pressure set controller, the event 158, signals can issue therefrom resulting from a requirement to lower the load. The lower load signal comes into the load adjust pulser, event 164, from the discharge pressure set controller, event 158. The lowering pulses from the event 164 are effective to put a signal on the "lack of high brake mean effective pressure" event 176 acting through an or-gate event 177 to provide a lower-speed event 178. This event 178 is effective upon the governor to reduce the revolutions per minute of the engine.

Also, a lowering pulse from the load adjust pulser event 164 is effective if cam 4 is in position, an event 179, through an or-gate event 181 to provide a signal if the speed is low, an event 182, or if the brake mean effective pressure is high, an event 183, to act through an or-gate event 184 upon an event 186. This determines that no upshift is simultaneously being attempted by the programmer. In the absence of such an attempted upshift event 186, then the signal through either the low-speed event 182 or thorugh the high brake mean effective pressure event 183 is effective to produce a progressive downshift event 187 at the programmer. The programmer continues to shift progressively in a downward direction one step or shift for each lowering pulse incoming from the load adjust pulser event 164, thus opening compressor pockets.

There are certain other occurrences that act in addition to the load adjust pulser or in addition to the discharge pressure set controller for governing the operation of the mechanism. For example, in the event 191 of excessively high brake mean effective pressure for any reason whatsoever, a signal is sent to an or-gate 192. Similarly, should for any reason whatsoever there be an unusually high differential pressure event 193 across the compressor, then a signal is likewise put to the or-gate event 192. In either of those instances a signal is transmitted to an or-gate event 194 interposed between the "lower" side of the discharge pressure set controller event 158 and the load adjust pulser event 164. Any impulse from the events 191 or 193 penetrates the or-gate event 194 and sends a lowering signal through the remainder of the network, with results as previously described.

A signal from either of the events 191 or 193 not only travels to the or-gate event 194 but likewise travels to an and-gate event 196. If it occurs that cam 12 is in position also; that is, there is a cam 12 event 197, meaning that the programmer is in one of its positions with all the compressor pockets open, then the and-gate event 196 passes a signal. The reason for cam 12 being in position is that the progressive downshift event 187 has occurred enough times so that the programmer has stepped downwardly, opening compressor pockets on the way, until it has moved into either Position 1, 2, 3 or 4, in all of which all pockets are open. Cam 12 is effective in all four of those positions, but only in those four positions. When a signal is on the and-gate event 196 and a signal shows that cam 12 is also in position, according to the event 197, then a signal leaves the and-gate event 196 and is effective thorugh an or-gate event 198 to provide a stop engine event 199. This is a quick shut-down of the engine, the aim being to stop the rotation of the machinery just as expeditiously as possible despite the fact that other instrumentalities may not be in appropriate stop position. This is virtually an emergency procedure.

There is also provided an emergency stop event 201 manually actuated or actuated in response to any selected signal. Should there be an emergency stop event 201, a signal goes out instantly to the or-gate event 198 and produces the stop engine event 199. The emergency stop event 201 also has other effects, to restore the system to starting condition even tough the engine may already be stationary. A signal from the emergency stop event 201 is effective upon an or-gate event 202. There is also a normal stop event 203 preferably manually actuated either locally or remotely which sends a signal to the or-gate event 130. The signal from the event 130 unlatches the latched crank event 121, should the engine cranking process have begun. Either the normal stop event 203 or the emergency stop event 210 produces an output effective to provide a latched stop event 204. This means that there is a predetermined stopping program initiated by an impulse from the or-gate event 202 and latched in condition and not interrupted until the orderly stopping procedure has been completed. The latched stop event 204 produces a signal to an and-gate event 206, likewise receiving a signal when cam 4 is in position.

The cam 4 event 207 with the latched stop event 204 cause the and-gate event 206 to send a signal through an or-gate event 208 to a reset pulser event 209. Output from the reset pulser is in two branches. One branch imposes a pulse on the or-gate event 177 to assure the lower speed event 178 in the event the stop is noraml, and the other branch from the reset pulser is effective upon the or-gate event 181 and thus to secure the downshift event 187. The or-gate 108 is likewise receptive to a signal from the start signal event 101, effective, just as is the signal from the and-gate event 206, to provide the reset pulser event 209 and the following events to bring the programmer down to starting setting, if necessary.

The latched stop event 204 not only affects the and-gate event 206, but likewise sends a signal to an and-gate event 211, also receiving signals from cam 3 in position, event 212, and cam 12 in position, event 213. That is, when cams 3 and 12 are both in position and a signal comes from the latched stop event 204, then the and-gate event 211 is effective to provide for a time delay event 214. This is simply a stopping procedure to permit the operating engine to reduce its temperature somewhat. Upon the elapse of sufficient cooling time, a signal leaves the time delay event 214 and is effective through the or-gate event 198 on the stop engine event 199 to make the engine stop. The signal from the time delay event 214 likewise is effective on an and-gate event 216, and as soon as the engine is completely stopped or dead a dead engine event 217 is also effective upon the and-gate event 216. At the conclusion of the cooling time delay when the engine is stopped, a signal causes the programmer to shift to a Position 3 event 218. The ultimate result of this shift to Position 3 is that the blow-down valve is closed, the bypass valve is closed, the suction valve is closed, and the discharge valve is opened.

What happens following the shift to Position 3, event 218, is that a signal goes to a close suction valve and verify event 219 to make sure that the suction valve is firmly closed. A signal then goes to an and-gate event 221. Also impressed upon the and-gate event 221 is the event 222 of the effectiveness of cam 2. This proves that the programmer is in Position 3, as shown by the event 218. In addition, a signal from the latched stop event 204 is transmitted to the and-gate event 221, so that when cam 2 is in position, and the suction valve is closed and the closure is verified, and there has been a latched stop impulse, a signal goes out to effectuate the shift to Position 2, event 223.

In the shift of the programmer to Position 2, only cams 1 and 12 are effective, as shown in FIG. 41, and while the programmer is in Position 2 the valve positioners are then actuated so that the blow-down valve remains in closed position, the bypass valve goes to opened position, the suction valve remains in closed position, and the discharge valve goes to closed position. A signal from the shift to Position 2, event 223, sends a signal to an event 224 effective to have the discharge valve mechanically closed and to have the verifier send a signal to an and-gate event 226. Also, a signal from the shift to Position 2, event 223, effectuates the opening of the bypass valve with a verification according to an event 227, the completion of which sends a signal to the and-gate event 226. Also, when there has been a shift to Position 2, cam 1 is in position according to an event 228. Finally, a signal from the latched stop event 204 is transmitted to the and-gate event 226. When all four of the events 224, 227, 228 and 204 are effective, the and-gate event 226 affords a signal to produce the event 229, which is a shift of the programmer to Position 1, in which only cam 12 remains in effect.

In Position 1 the blow-down valve is opened, the bypass valve remains opened, the suction valve remains closed, and the discharge valve remains closed. This is accomplished in that a signal from the event 229 goes to the event 231, which is effective to move the blow-down valve to open position. Furthermore, an outgoing signal from the event 229 in the absence of cam 1, an event 232, sends a signal back to the latched stop event 204 and unlatches such stop. All of the normal stop procedure has now been completed and the system is left in appropriate condition for a subsequent start. The entire operation of the engine has thus been conducted through an automatic start sequence, the compressor has been put on the line, its output has been regulated, emergencies have been taken into account, and the compressor has been taken off the line and the engine has been shut down either by an emergency stop procedure or by a normal stop procedure.

In a typical or representative environment and as an example for description herein, an installation is made in a pipeline 301 (Sheet 1) usually conducting natural gas from a source (not shown) through a suction pipe 302 and a discharge pipe 303 leading to the next pumping station or to a point of discharge. Flow from the suction pipe 302 is into a positive displacement, engine-driven compressor 304 and from the compressor to the discharge pipe 303 with an increased pressure in the gas being pumped. Although installations vary, it is usual to provide a suction valve 306 interposed in the suction line 302 and under the control of a valve actuator 307, so that the suction valve can be open or closed as desired, the valve being illustrated in it closed condition.

In a similar fashion, the discharge line 303 usually includes a discharge valve 308 illustrated in closed position and arranged to control flow from the compressor installation into the line 303. A valve actuator 309 moves the discharge valve between open and closed positions.

Since it is sometimes desired to have gas flow around rather than through the compressor, there is provided a shunt pipe 311 extending directly from the suction line 302 to the discharge line 303. In the shunt line 311 there is a bypass valve 312 illustrated in open position and arranged to be opened or closed by a valve actuator 313. Furthermore, since it is often advantageous to purge a portion of the line, particularly the compressor loop or those portions of the pipeline between the suction valve 306 and the discharge valve 308, there is provided a purge pipe 314 around the suction valve 306, the purge pipe 314 carrying a purge valve 316 having an actuator 317 connected thereto. The actuator 317 is normally spring-closed and is effective to permit gas flow through the purge pipe only when the actuator is energized. The actuator holds open the purge valve as long as the energization lasts.

In addition, beyond the bypass valve 312 the shunt pipe 311 is provided with a blow-down connection 318 leading to the atmosphere or a suitable point of discharge through a blow-down valve 319, shown in its open position, and being controlled by an actuator 321. Various functions and operations of the valves will be discussed later on.

The compressor 304 itself is preferably a reciprocating, positive displacement double-acting mechanism, both the head end and crank end compression chambers of which are provided with several clearance pockets diagrammatically and generally designated 322 (Sheet 2), each of which can be opened into the adjacent compression volume or can be segregated therefrom by means of a pocket valve 323 of a standard kind and illustrated diagrammatically. Each valve is moved between open and closed position by an associated one of a corresponding number of pocket valve actuators 324, the effect of which is to vary or permit change in the discharge pressure from the particular compression volumes of the compressor.

To drive the shaft 325 of the compressor 304 there is mechanically connected thereto a suitable internal combustion engine 326. This is preferably a multi-cylinder, single-acting, reciprocating, V-type engine operating on natural gas with spark ignition and being provided with the usual attributes of similar engines.

In accordance with the invention, means are provided for appropriately actuating the various pipeline valves, various of the compressor mechanisms and various of the engine mechanisms in such a fashion that the net result will be a controlled transfer and compression of the gas through the pipeline 301. Also in accordance with the invention, mechanism is provided so that the attendant has a choice of the manner or mode in which the engine and compressor and valves are supervised; that is, to provide at the attendant's choice any one of four different optional programs. The first option is a largely manual one in which the attendant is required to perform various of the control operations himself and according to his best judgment. This is mechanically the simplest program and is referred to as the "manual" mode. The next option is what is referred to as an "automatic start-stop" mode. This means that most of the engine start and stop functions are performed automatically but the attendant still must provide some manual operation or manual selection of a few of the events required.

The next most fully automatic arrangement is like the second mode but has in addition a programmed arrangement to impose the pumping load onto the compressor and to withdraw the pumping load from the compressor. This mode is referred to as an "automatic start-stop and load" mode. Finally, the most nearly automatic arrangement is to include all of the automatic features of the preceding modes and in addition to have an automatic adjustment of the ability of the structure to adjust itself in response to increasing or decreasing loads. This fourth mode is referred to as an "automatic start-stop, load and load adjust" mode.

The attendant has a choice of the particular one of the four modes in which he wishes the structure to operate at any particular time. His choice is manually effectuated by a mode selector structure 331 (Sheet 4). This device has a frame on which there is a rotatable shaft 332 having a hand operator 333 thereon and carrying a series of cams 334A, 334B, 334C and 334D. Each of the cams has a contoured projection effective to operate against related roller plungers 336A, 336B, 336C and 336D controlling associated valve mechanisms 337A, 337B, 337C and 337D urged against the associated cams by springs 338.

It may first be assumed that the attendant has decided to initiate operation in the "manual" mode. To do so, he moves the crank 333 out of its inactive position and into a position in which the cam 334A is effective upon the follower 336A to shift the valve mechanism 337A against the spring 338 out of the position shown in the drawing into a translated position. The cam contours are such that only the first valve is operated when the crank 333 is moved into the "manual mode" location. (See FIG. 42) When the valve 337A is so shifted, it makes effective a supply of actuating fluid or gas, such as natural gas, air or some inert gas.

For present purposes and to avoid confusion with the material being transported in the pipeline or with the engine fuel, the actuating fluid herein is referred to as air. Air under pressure from a source 339 flows through a pressure regulator 341 in which the pressure is reduced to a selected value; for example, 60 pounds p.s.i. This is a general supply of air, sometimes referred to as the main or manual supply, and flows through a pipeline 342 (Sheet 4) to a number of supply lines 343, 344, 345 and 346 to the respective valve mechanisms 337A, 337B, 337C and 337D. The valve 337A, having been displaced to effectuate the manual mode, is effective to disconnect an air line 347 from its previous connection to an atmospheric vent line 348 and to connect the manual supply line 343 therewith. The air line 347 has a branch which supplies operating air to a manual start device 349 (Sheet 4).

The manual start mechanism 349 has a frame like the mode selector and includes a rotary shaft 350 with a crank handle 351. Fast on the shaft 350 is a plurality of cams 352, 353, 354 and 355, each having an appropriate contour, and sometimes designated cams 1, 2, 3 and 4. The cams are individually effective upon respective ones of roller followers 357, 358, 359 and 360 controlling valve cores 362, 363, 364 and 365 returned by respective springs 367. The valve cores are substantially identical, and the manual mechanism 349 itself is similar to the mode selector mechanism 331. An exception is that the initial valve follower or stem 357 is not solid, but has a toggle hinge 368 with a return spring so that it is actuated during only one direction of rotation of the cam shaft 350. The effective direction is indicated as counterclockwise by the arrow on cam 1 on Sheet 4. In the return or reverse operation of the crank 351 (clockwise) the follower buckles and the valve is not displaced against the spring 367.

In the leftward displacement of the core 362, manual air under pressure from the air manifold 347 travels through the valve and then travels through a duct 369 to a cranking gas valve or-gate 370. This or-gate is a logic element commercially available and diagrammatically shown in FIG. 4. It is effective to afford a corresponding air outflow whenever either one or both of two air inflows occurs. In the present instance, the flow in the duct 369 is to the a port of the or-gate and through the c port of the or-gate 370 to continue through a pipe 371 and extends to a control valve (not shown) for a cranking motor on the main engine 326. Preferably the cranking motor operates on gas under pressure and is effective when the control valve is open to rotate the main engine for cranking or starting purposes. Sometimes several cranking motors are used and are simultaneously controlled by one valve, as regulated by the air in the pipe 371. The line 369 upstream of the or-gate 370 has a branch path through a conduit 372 extending to a reset or-gate 373 (Sheet 13).

Outflow from the reset or-gate 373 is through a line 374 to a "Shut-down Pressurizer" board A (FIG. 12). This circuit board is typical of the circuit boards utilized herein. It includes, as a sort of sandwich construction, a pair of outside plates between them securing an intervening sheet having configured passages therein leading between various ports, most of them at the edges of the board. Supported on the outside plates and opening through ports therein are various, commercially available pneumatic logic units. Examples are diagrammatically shown herein in FIGS. 4-11 inclusive. They are in more detail shown in the catalog 6619-TR of The Aro Corporation, Bryan, Ohio, entitled "Pneumatic Logic Controls," copyright 1966. The logic controls are illustrated herein in the circuit boards pursuant to standard schematic showings. The convention is followed herein of designating each of the boards by a general title and by an alphabetic, letter designation. Furthermore, the edge ports on a board, usually eight in number, are designated first with the letter of the board and then with the numeral of the port. For example, the line 374 which goes to the board A is connected to the number 8 port of that board, herein designated A8.

From the port A8 (FIG. 12) there is within board A a connection to the c port of a set-reset unit 375. An outgoing connection is from the b port thereof to the a port of a memory unit 376, the c port of which is connected to the a port of an and-gate 377, from which the c port is connected to the a port of an or-gate 378. Other factors are required in this portion of board A to produce the desired functions. For that reason, pressurizing fluid from the manual or M supply line 347 (Sheet 4) is conducted through a line 379 to a shut-down pressurizing or-gate 380, output from which is taken by a line 381 to port A7, from which flow is through a duct 382 to the b port of the memory unit 376 and through a duct 383 to the b port of the and-gate 377. Under this condition, flow is from the c port of the and-gate 377 to the a port of the or-gate 378, from the c port of which flow continues through a line 384 to port A3. A line 385 connects the port A3 to an orifice 395 (Sheet 13), from which flow continues through a line 386 to pressurize a number of series connected shut-down controls 387A, 387B, 387C, 387D, and so on, the last such control being 388.

These shut-down controls 387A, etc., are standard units effective to give an indication and to vent the air supply line thereto immediately whenever an input signal from some critical portion of the engine, the compressor or the environment indicates an unsafe condition. That is, if some part of the structure or portion of the environment is not functioning properly, the corresponding shut-down control is made aware of that fact and does not permit pressure air to continue through the series of shut-down controls, but rather vents or depressurizes the pressure air line. Some of the shut-down controls are effective before engine operation; for example, to warn of a hazardous atmosphere or an improper lubricating oil condition. Some of these shut-down controls are not activated until the engine and compressor are in operation. That is, some shut-down controls are responsive to functions of the mechanism in operation; for example, excessive brake mean effective pressure in the engine. To energize all of them initially would let them block further operation simply because the rotating machinery is not operating.

For that reason, the shut-down controls are arranged in two major groups, Group I being utilized from the very starting of the machinery and the other, Group II, being utilized only after the machinery is going. The shut-down controls 387A, etc., connected to the line 386 belong to the second group. Consequently, means are provided for blocking out the operation of the second or Group II shut-down controls, such as 387A, etc., during the initial or starting operation.

For that reason the line 386 is connected not only to the initial one of the Group II shut-down controls 387A and in series to the other controls of that group, but a line 389 from the final control 388 of Group II shut-down controls extends to a three-way valve 390 spring-urged into the position shown (Sheet 13). However, when there is flow from the or-gate 378 into the line 384 and the port A3, there is also flow to the b port of a not-gate 391 (FIG. 12), from the c port of which a line 392 is connected to a port A4. From there a line 393 extends to a pressure cell 394 effective to actuate the valve 390.

Since in starting there is no blocking impulse on the not-gate 391, flow continues from port A4 to the pressure cell 394 and shifts the valve 390 from the position shown into a position in which the line 389 is blocked and inhibits any signals from the Group II controls. Flow from the or-gate 378 is likewise into a line 396, having a restricting orifice 397 therein, to a port A5 and into a line 398. In the shifted position of the valve 390 there is communication from the line 398 to a conductor 399 extending to the Group I series of shut-down controls beginning with control 401 and ending with control 402, progressing in series to controls 401A, 401B, 401C, 401D, etc. These Group I shut-down controls are all series connected and so are effective during the starting operation of the machinery.

On the assumption that none of the Group I shut-down devices 401-402 is interrupting the series circuit, because all of the signals that they get are favorable, then air flow continues from the final shut-down unit 402 to a conductor 403, having a branch 404 extending to a "Shut-down Timed Lock-out" board B (FIG. 13, Sheet 13) and particularly to a port B5 thereof. In the board B flow continues through a duct 406 to the b port of a not-gate 407 (the a port of which is not presently active) and from the c port of the not-gate 407 to a port B6 and through a conductor 408 to one port of an and-gate 409 (Sheet 13) connected to an indicator 411. This shows, when effective, that the Group I shut-down controls; that is, the controls 401-402, are armed. However, another signal is necessary to the other port of the and-gate 409 before there can be any display.

From the conductor 403 flow continues through an orifice unit 412 and a duct 413 to a normally vented vent valve 414. This valve is moved by a pressure cell 416 connected by a duct 417 to the branch 404. Thus, as soon as pressure builds up in the conductor 403 and in the branch 404 due to the restriction of the orifice 412, the pressure cell 416 shifts the vent valve 414 into a blocking position against its normal closure spring and closes the connection of the duct 413 to vent. Flow continues in the now end-blocked duct 413 to a pressure cell 418, which in turn immediately shifts a valve 419. This has previously been spring-pressed into a position to connect to vent. When so shifted, the valve 419 connects a line 421 connected to the line 342 (Sheet 4) carrying M pressure air to a conductor 422 (Sheet 13) leading to a fuel gas shuttle valve 423. This is a form of double check valve.

Flow out of the valve 423 is through a line 424 into a manifold 426 at its lower end connected to port A6 and within the board by a connection 427 to the a port of the set-reset unit 375, thus resetting the unit 375, and the the b port of the or-gate 378, so that flow continues to the line 384 and the line 385. The manifold 426 is also connected by a line 428 to the other port of the and-gate 409, so that upon appearance of signals in both the lines 408 and 428 at the and-gate 409, the outlet port thereof is pressurized and the indicator 411 is energized to show that in fact the Group I shut-down units are armed, and the starting operation can continue. In some instances where a remote indicator is wanted, the manifold 426 has a branch 429 extending to a similar indicator on a remote telemetering panel.

With the cranking gas valve open by pressurized line 371 (Sheet 4) and the cranking motors rotating the main engine and compressor, and with the Group I indicator 411 showing that conditions are favorable for continued starting operations, the attendant turns the shaft 350 to the next position so that the cam 353 shifts the valve 363 (Sheet 4) from its spring-pressed, vent position into an effective position. Flow from the air line 347 continues through the valve 363 to a line 431 extending to the a port of an ignition or-gate 432. Flow continues from the c port of the or-gate 432 through a flow controller 433. This includes a restricted orifice 434 to throttle backflow and includes a check valve 436 readily opened by air flow in the starting direction. For starting, pressure is so supplied to an operating diaphragm 437 effective upon an ignition switch 438. This switch is located in a conductor 439 leading from an ignition magneto (not shown) driven by the engine and through the conductor 439 connected to a ground 441. When the switch 438 is closed, the magneto is grounded and there is no ignition current, but as soon as the diaphragm 437 expands, the switch 438 is opened and the magneto is no longer grounded, but is effective to furnish ignition to the various engine cylinders.

Thereupon the attendant continues rotation of the shaft 350 so that the cam 354 displaces the valve 364 from its vent position to its active position conducting air from the air line 347 to a line 442 leading to the a port of a starting fuel gas or-gate 443. Flow continues from the c port thereof through a duct 444 leading to a pressure cell 446 (Sheet 13) which when energized is effective to overcome a valve spring and to shift a valve 447 from its normal position blocking one end of the manifold 426. The valve shifts into a position in which the manifold 426 is connected to a previously vented pipe 448 joined to the valve 447 and extending to a flow controller 449. This controller includes an orifice 450 permitting restricted flow away from the valve 447 and includes a check valve 451 permitting free flow in the opposite, venting direction. From the controller 449 a conductor 452 extends to the actuator portion of a fuel gas block and vent valve (not shown). When pressurized, the actuator portion is effective to move the fuel gas valve from its closed position into a position sufficiently open so that a relatively small supply of operating fuel is furnished to the now rotating and sparking engine, which starts to operate under its own power.

In the event of some difficulty at this point, the attendant can return his crank 351 to off position or if it should be decided at this point or at any time to have an emergency shut-down of the mechanism, there is afforded means to do so. A branch 453 (Sheet 13) from the conductor 452 extends to a valve 454 having a mechanical connection 456 to a similar valve 457. The valve 454 is normally spring-held in blocking position, as is the valve 457. When a manual button 458 is depressed in emergency, the valve 454 is mechanically shifted to connect line 453, and so line 452, to vent. A branch 459 from the line 403 is connected to the valve 457 and is similarly vented when the button 458 is depressed. This promptly shuts down the starting operation or any other operation by venting the supply lines.

Absent an emergency stop, when the starting gas is supplied to the rotating engine in the presence of ignition, the engine starts to operate under its own power but at a relatively slow speed since the starting gas supply is restricted. Rotation of the engine is responded to by the attendant, who turns the shaft 350 somewhat farther. While the cam 353 still holds the valve 364 in starting gas position, the cranking gas cam 352 advances into a situation permitting the cranking gas valve to shift back to venting position. The cranking gas supply is thus discontinued. Thereafter should the operator for any reason turn the shaft 350 in a reverse direction in order to shut down (instead of using the emergency shut-down button 458), he will not re-energize the cranking motor. The connection 357 to the valve 362, being a one-way connection, in its reverse movement permits the cam simply to go by without displacing the valve.

With the engine operating properly on starting fuel, the attendant next moves the control shaft 350 to its next or final position and so turns on the running gas. He usually waits momentarily until the engine has settled down smoothly to its starting speed, after the cranking gas has been turned off. Rotation of the shaft 350 then causes the cam 355 to shift the valve 365 from its spring-pressed vent position into an effective position. In this valve position, air from the air line 347 is discharged through a duct 461 into a fuel gas or-gate 462. From the outlet of the or-gate 462 flow is into a line 463 through a flow controller 464 having an orifice 465 therein, flow through a parallel check valve 466 being blocked except in the reverse direction. From the controller 464 flow is through a conduit 467 to a running fuel gas valve actuator (not shown), the effect being that the running gas valve is opened to supply the engine with its normal amount of operating fuel. From the conduit 467 there is a line 468 provided with an accumulator 469 and extending to port A1 of the shut-down pressurizing board A (FIG. 12, Sheet 13), within which flow is through a duct 471 and through an or-gate 472. Flow from there is into a timer 473 connected to an accumulator 474 and by a line 476 extending to the a port of the not-gate 391.

Upon appearance of pressure from the line 468 (when the run-gas valve is actuated open) at the a port of the not-gate 391, the not-gate precludes further flow between the b port and c port of such gate, so that the lines 392 and 393 are exhausted. Consequently, the pressure cell 394 is dropped in pressure and the spring-urged valve 390 shifts back to the position shown, so that the duct 389 connected to the Group II shut-down devices 387A-388 is then continued through line 399 and both groups of shut-down devices are operative. Thus when line 389 is so connected to line 399, a branch line 477 connected to the port B7 of the board B is joined through a duct 478 therein to the b port of a not-gate 479. Flow continues from the c port of the not-gate 479 through a duct 480 connected to port B8, from which a conductor 481 goes to the a port of an and-gate 482 (Sheet 13). The b port of the and-gate 482 is joined by a conductor 483 to the manifold 426. Upon the appearance of pressure at both ports thereof, there is an output through the c port of the and-gate 482 to an indicator 484 showing that the Group II shut-down devices are likewise armed and effective.

There is provision for a shut-down timed lock-out. This is an arrangement so that the integrity of the various shut-down mechanisms such as 387A, 401 and the like can, at the option of the attendant, be tested or checked for correct operation while the machinery is running. If any shut-down device were arbitrarily disconnected for testing during engine operation, the engine would be shut down by closure of the running gas block and vent valve since the inoperative shut-down device would vent the line 452. It is deemed beneficial to have a short, predetermined time delay under attendant supervision before the main gas valve closes due to a shut-down signal, the delay being long enough, say five minutes, but only long enough to allow the attendant to test the shut-down circuitry.

There is provided a normally spring-pressed valve 485 (Sheet 2) normally in vent position but movable by a thumb button 486 into a pressure position. The button 486 when momentarily depressed by the attendant affords a brief connection between an air line 487 from the supply line 342 through a line 488 to the port B4 of the board B (Sheet 13). From port B4 pressure is transmitted through a duct 489 to a set-reset element 491 connected to a memory unit 492 and from there to the a port of an and-gate 493. The b port of the and-gate 493 is supplied with M air pressure through a duct 494 connected to the port B1 and through a branch 495 to the line 381 from the shut-down pressurizing or-gate 380 (Sheet 4). When the depressed button 486 energizes the set-reset unit 491, that in turn conditions the memory unit 492 to pass air from the line 494 through a connector 496 and the memory unit 492 and through a duct 497 to the and-gate 493 so that pressure appears at the port B2. There is outflow from port B2 through a passage 498 to the fuel gas shuttle valve 423. This new supply of M air shifts the ball in the shuttle valve 423 and, while blocking the line 422, maintains pressure in the line 424 and its connections so that the line 452 to the fuel gas valve stays in active, valve-open condition.

Within board B there is a duct 499 connecting the line at port B2 to a line 500 in which an orifice 501 is situated. The line 500 is pressurized from port B2 when the and-gate 493 is open through the line 499 and so supplies air at a rate controlled by the rofice 501 through port B3 and a line 502 to an accumulator 503. An and-gate 504 is connected across the lines 489 and 500, but since the line 489 is pressurized only momentarily while the button 486 is depressed, the and-gate 504 is only momentarily connected to vent. Thus, when the button 486 is spring-returned, there is no signal on the a port of the and-gate 504, so that line 500 is not then vented and the accumulator 503 charges and requires a set time, say 5 minutes, to come up to operating pressure from the line 494.

The line 500 is connected to the a port of the not-gate 407 and when pressurized stops the signal at port B6, thus de-energizing the and-gate 409 and extinguishing the indicator 411 for the Group I shut-down devices. Also, a line 505 from the line 500 extends to the a port of the not-gate 479, thus depriving the port B8 of pressure so that line 481 loses its pressure and disables the and-gate 482, so extinguishing the indicator 484 for the Group II shut-down devices.

When pressure has built up in line 500, a signal is impressed through a duct 506 on the a port of an and-gate 507, the b port thereof already having a signal from the line 494 through a connection 508. The and-gate 507 then sends pressure through a duct 509 to the a port of the set-reset unit 491. This then correspondingly resets the memory unit 492 to stop output through the c port thereof, thus disabling the and-gate 493 and restoring the parts to their original condition.

Should the attendant need more time, he can, before the expiration of the set period, again momentarily depress the button 486, thus venting the accumulator 503 through the and-gate 504 and permitting a repeat of the cycle with the empty accumulator again starting a new 5-minute lock-out of the shut-down devices.

When the mode selector 331 is in the manual mode, during which the manual start mechanism is utilized, it is helpful to have an arrangement so that the various pipeline valves can be air operated under manual control as well. For that reason, the manual pressure manifold 347 (Sheet 4), effective in the manual operation mode only, is extended to connect (Sheet 8) to a manually operable suction valve control 511, a manually operable discharge valve control 512, a manually operable blow-down valve control 513 and a bypass valve control 514 likewise manually operable. The spring-closed purge valve 316 is separately cared for. The manual button 515 on the suction valve control 511, which is typical, is effective to shift the valve spool 516 into different positions.

In the illustrated position of the valve 511, when the manual button 515 is not depressed, flow is from the line 347 through the valve to a pressure line 517 leading to port C5 on a "Suction Valve Control" board C (Sheet 8, FIG. 14). From the port C5 pressure goes through a duct 518 and through an or-gate 519 to a duct 521 leading to port C6 connected by a line 522 leading to the "opening" end of the actuator 307 (Sheet 1). This urges the suction valve 306 toward open position. The valve can so move because the other side of the actuator is vented. Another line 523 from the suction valve actuator 307 extends to port C8 of board C. Within the board there is a duct 524 extending to an or-gate 526 and through a duct 527 to the port C7, from which a line 528 goes to the portion of the valve spool 516 in the position shown connected to a vent line 529. Thus, when the valve 511 is not depressed, air pressure urges the suction valve to move toward and stay in open position. When the manual button 515 on the control 511 is depressed, the core 516 is shifted to reverse the air connections, so that the line 523 becomes pressurized, the line 522 is connected to vent, and the suction valve is urged toward closed position under manual control.

From the supply line 347 an extension goes to the discharge valve control 512. This has a core 531 shiftable by a manual button 532. In one position of the valve, pressure travels through the valve core to a line 533 going to a "Discharge Valve Control" board D (FIG. 15, Sheet 7) and being connected to port D5. From this port pressure is transmitted through a duct 534 to an or-gate 536, from which flow continues through a duct 537 to a port D6. A line 538 extends to the b port of an and-gate 539.

To make sure that the discharge valve is opened only under appropriate pressure circumstances, there is provided a line 541 (Sheet 1) connected to the discharge line 303 upstream of the discharge valve 308 and connected to be effective upon a pressure cell 542 (Sheet 7). This cell in turn moves a control valve 543 normally spring-pressed into its vent position. When there is sufficient pressure in the discharge line 303, the valve 543 is shifted against the spring and connects a line 544 (connected to the actuating pressure line 421) to a conductor 546, at the same time closing off the previously effective vent. The line 546 is thus pressurized and transmits the pressure to the a port of the and-gate 539. Under those circumstances, and since the b port of the and-gate 539 is already pressurized, flow continues from the and-gate 539 through a line 547 to the "opening" portion of the discharge valve actuator 309, moving the discharge valve 308 toward open position.

The discharge valve control 512 has a vent connection 548 in one valve position venting a line 549 joined to port D7 and connected by a duct 551 in the board to the b port of an or-gate 552. The outlet port c of the or-gate is joined by a duct 553 to port D8, from which a connection 544 extends to the closing end of the discharge valve actuator 309. When the discharge valve control 532 is manually moved to an intermediate position, the actuator 309 is held in an intermediate position. When the valve core 531 is shifted to the opposite extreme position, the lines are crossed and the previously vented line 554 is pressurzied and the previously pressurzied line 547 is vented, and the discharge valve is moved toward closed position.

Comparably, the blow-down valve control 513, being fed from the line 347, is provided with a core 556 which connects to the supply line 347 and to a vent line 557. In one valve position, the supply line 347 is connected through the valve control 513 to a line 558 which extends to a "Blow-down Valve Control" board E (FIG. 16, Sheet 7) and is connected to port E3 thereof. From that prot there is a duct 559 extending to the b port of an or-gate 561, from the c port of which a line 562 leads to port E2. This is joined to a line 563 leading to the opening end of the actuator 321 for the blow-down valve 319. Pressure therein tends to move that valve toward open position.

From the blow-down valve control 513 there is also a line 564 which extends to the E6 port of the board E and through a duct 565 therein into an or-gate 566, from which flow continues through a line 567 to and through a not-gate 568 to the a port of an and-gate 569. The other side of the and-gate 569 is connected through a duct 570 and a line 571 to a port E1 exteriorly joined by a conduit 572 to the line 381 from the shut-down pressurizing or-gate 380 (Sheet 4). Thus, when there is pressure at the port E1, and also pressure at the port E6, the and-gate 569 is effective to permit flow to continue through port E7 to a line 573 extending to the closing end of the blow-down controller 321.

The control board E downstream of the or-gate 566 and in the line 567 has a connection 574 to a not-gate 576, the c port of which is connected by a line 577 to the a port of an and-gate 578, the other side of which, or b port, is connected by the line 571 at port E1 to the pressure line 572. The outlet from the and-gate 578 at the port E8 is joined by a line 579 to an or-gate 581, flow from which is through a line 582 to the purge valve actuator 317. Since that valve is spring-closed, it remains open only so long as there is pressure in the line 582.

Also connected into the line 567 in the board E is a timer 583 joined by a duct 584 to an accumulator 586, both the timer and the accumulator being connected to the a port of the not-gate 576. This arrangment is such that when pressure to close the blow-down valve is present at port E6 and in line 565, the timer 583 and accumulator 586 begin to be charged, and flow through the not-gate 576 into the line 577 inhibits the not-gate 568 so no output is available at port E7. But the pressure in line 577 does complete the signals to the and-gate 578 (already pressurized through the line 571) so pressure is made available at port E8. This is effective to open the purge valve. Then, when the timer 583 and accumulator 586 are charged, their pressure is then sufficient to inhibit the not-gate 576 at port a, dropping pressure in line 577, stopping the signal to the purge valve, which spring closes, and also releasing the not-gate 568 so that the signal then appears at port E7 and the blow-down valve is moved to closed position.

There is an alternate actuator for the purge valve 316 effective to open the purge valve briefly just before the discahrge valve 308 opens. The line 538 (Sheet 7) which pressurizes the b port of the and-gate 539 has a branch 588 leading to the b port of a not-gate 589, the c port of which is connected by a condutor 591 to the a port of the or-gate 581. When the line 538 is pressurized, no signal passes the and-gate 539 since the a port thereof is vented through the line 546 and the valve 543. But as the line 588 is pressurized, and since the not-gate 589 is vented at port a and is not inhibited, the signal passes through to the conductor 591 and so opens the purge valve 316. When the gas pressure within the line 303 builds up accordingly, it is effective through the line 541 on the pressure cell 542 and shifts the valve to pressurize the line 546 from the line 544. This pressure at port a inhibits the not-gate 589 and stops pressure from line 591, so the purge valve spring closes. Also, the pressure in line 546 enables the and-gate 539, already pressurized at port b, to be pressurized at port a and so furnish a signal through port c and line 547 to open the discharge valve.

The bypass valve control 514 (Sheet 8) has a core 592, a manual button 593 and a vent 594. The valve 514 is connected to the pressure supply 347 and when the valve core is in proper positon, pressure connection is made to a line 596, which extends to a "Bypass Valve Control" board F (FIG. 17, Sheet 8). The line 596 connects to the port F5 and through a duct 597 to an or-gate 598, flow from which is through a duct 599 to the port F4 and into a duct 601 extending to the closing end of the bypass valve actuator 313. In a parallel fashion, the vent 594 is connected through the core 592 to a line 602 extending to port F8, from which flow is through a duct 603 and an or-gate 604 to a duct 606 leading to the port F7 and to a line 607 extending to the opening end of the bypass valve actuator 313. When the bypass valve control 514 is in one position, the bypass operator is pressurized in the closing end and the bypass valve is urged toward closed position, whereas when the manual button 593 is depressed to shift the valve core 592, the pressure and vent lines are reversed and the bypass valve is urged from its closed position toward its open position.

With the foregoing valve control buttons, the attendant can at his discretion operate the various valves between open and closed positions and, in some cases, can hold a valve in an intermediate position.

During manual operation it is often desired to vary the load on the compressor by some sort of hand control by the attnedant. The compressor, as in common with many compressors, is provided with a series of clearance pockets generally designated 322 (Sheet 2) opening into each one of the compression volumes. Each of these pockets communicates with the related compression volume under the control of a normally spring-closed valve, generally designated 323. The valve itself can be moved in any appropriate way. In the present instance there are four crank-end pockets and there are four head-end pockets. Since the arrangements for all of these pockets are virtually the same, the description and illustration of one is intended to apply equally to the others. For example, the illustrated first pocket 322 at the crank end has a connection to its valve 323 from a pilot actuator 324 normally urged into one extreme, open position by a spring but movable by air pressure out of that position into an opposite position with the pocket closed. To accomplish this movement, there is provided, with the mode selector is in the manual mode, a pipe connection 622 (Sheet 4) from the line 379 carrying manual air M under pressure.

The connection 622 proceeds through a pocket unleader or-gate 623 and a connector 624 to a manifold 626 conneted to eight manually operable valves 627. The description of one valve 627 applies to all. Each of the valves 627 is normally connected to vent but when depressed by a push button 628 affords connection between the manifold 626 and a line 629 passing through an appropriate or-gate 631 of a group of or-gates, each joined by a pipe 632, one of a group of like pipes, to the pilot valve actuator 324 or the respective actuators for the other pocket valves. Since all of the pockets are similarly equipped, the attendant can at any time at his discretion simply by depressing the proper one or ones of the manual buttons 628 charge any one or more of the pilot actuators 324 to close any one or more of the crank-end and head-end pockets such as 322. He can similarly put any one of the pockets back into operation by changing the position of the manual control 628 of the corresponding valve 627. By manual operation the attendant can include or exclude as many of the pockets or whichever pockets he desires to adjust, not only the crank-end load of the compressor, but likewise the head-end load and the load on the compressor as a whole.

With the manual mode controls as thus far described, the attendant by operating the crank 351 and rotating the shaft 350 can start the engine manually, bringing it up to speed. He can check the effectiveness of the shut-down controls. He can connect or disconnect the compressor from the main gas line and can have the compressor assume the load under his control. By reverse operation of the shaft 350 he can stop the engine and restore it to dead condition or he can make an emergency stop.

Instead of relying solely on a manual control of the mechanism, it is possible to adopt an automatic control leaving some special functions under the control of the attendant but having other, usual functions taken care of automatically. For example, a more sophisticated option for the attendant is what is called an "automatic start-stop" mode.

This mode is selected by movement of the crank 333 and rotation of the shaft 332 (Sheet 4) from an off position through the manual position, goverened by the cam 334A, into the next position, governed by the cam 334B. When in active position, the cam 334B (Sheet 4) displaces the valve spool 336B and translates the valve core 337B. When this is accomplished, the valve 337B has been moved from its inactive, vent position into a position in which the manifold connection 344 from the air supply manifold 342 is connected to a pipe 636 effective to charge an actuating cell 637 to overcome the resistance of a spring and shift the core of a valve 638. This valve effects or establishes in several connected pipes, previously inactive, what is referred to as an A1 pressure air supply, supplementary to the M air supply previously described.

The shifted valve 638 establishes a connection from the main air supply line 342 directly through a line 639 and a branch 641 to furnish A1 air to a conduit 642 going to the pocket unloader or-gate 623. The A1 pressure air is supplied through the line 642 to a line 643 which serves as a main A1 air supply conduit for this particular mode of operation. There is an A1 supply connection 644 to a locally situated manual start, push button valve 646 and a connected manual stop, push button valve 647. These are often located away from the control panel on which the cranks 333 and 351 are disposed. The two valves 646 and 647 are preferably spring-urged apart and are connected by a mechanical link 648 to make sure that when one is actuated the other one is inactive.

In some instances in addition to the local start and stop push button valves there is provided at some distant point another or "remote" start and stop mechanism. The local and remote stops are always workable, but it is preferred to select either remote start or local start, but not both. A locally disposed valve 649 having a manual push button 651 is normally positioned so that when the local start valve 646 is actuated a connection is made through a previously vented line 652 to the A1 air supply line 644. This charges the line 652 and transmits pressure through the valve 649 to a conductor 653. Should the control 651 be in its other, "remote start" position, then pressure through a line 654 from a start button at the remote location is effective to charge the conductor 653. Under local start conditions, the depression of the button to translate the valve 646 makes sure that the stop valve 647 is in an inactive position and that air under pressure is transmitted from the supply pipe 644 to the conductor 653.

The A1 air supply is also furnished, in connection with the second mode or automatic start-stop mode, to a mechanism in the nature of a programmer, so that various events are governed to take place automatically in the sequence desired. The programmer 660 is particularly illustrated in a diagrammatic form (on Sheets 11 and 12) and includes a frame 661 on which is mounted a rotatable shaft 662 at one end carrying a ratchet wheel 663. This can be advanced in one direction or clockwise, as seen in the drawings, one step at a time by a pawl 664 impelled by a spring-returned power cylinder 666. For each impulse of the power cylinder 666, the ratchet wheel 663 and the shaft 662 are driven clockwise one step. In one embodiment, the programmer shaft makes about 20 steps in a substantially complete revolution, of which only 16 are utilized in the present arrangement. Similarly, the ratchet wheel 663 is propelled in a counterclockwise direction one step at a time by a pawl 667 driven by a spring-returned piston in a pressure cylinder 668, so that the shaft can be rotated counterclockwise one step at a time and through the desired number of steps.

Disposed on the shaft 662 at axially spaced intervals are cams 669 collectively, each of which carries an individual designation. Since 12 cams are utilized herein, the cams are individually designated 669-1 to 669-12 and for convenience are referred to as cam 1 to cam 12. Each of the cams is provided with a suitable peripheral contour. In practice this is effectuated by a number of removable cam lugs, not shown, which can be given individual shape and individual peripheral extent, as desired. In this way the programmer can be changed from time to time to afford different programs and to afford events of different duration and timing. Each of the cams is designed to operate against one of a dozen identical cam followers 671, each of which governs the position of an associated, spring-returned valve core 672. There are twelve cores and valves. Each is identified by the number 672 and the number of the cam with which it is associated; for example, 672-1.

As particularly shown in FIG. 41, the programmer positions and the effectiveness of the various ones of the 12 cams 669 and valves 672 are disclosed. Fro example, when the programmer 660 is in Position 1 (at one extreme), only cam 669-12 is effective to translate its valve 672-12. In the next step or in Position 2 of the programmer, cam 12 is still effective but in addition cam 669-1 (cam 1) and valve 672-1 become effective. In position 3 cams 12 and 1 remain effective and in addition cam 669-2 (cam 2) and valve 672-2 become effective, and so on. FIG. 41 by the representation of an x in the coordinate square indicates that the related cam is effective to displace its valve 672 and allow air flow, and the absence of an x indicates that the related cam is not effective and that its corresponding valve 672 is spring-pressed to a vent position.

The operation of the programmer, upon depression of the button of the local start valve 646, depends upon the A1 air supply from the valve through the pipes 652 and 653. The pipe or conductor 653 from the start valve 646 (Sheet 2) extends to a port G3 on an "Upshift To Position 2" board G (FIG. 18, Sheet 3). The port G3 is joined to the a port of an and-gate 676, the c port of which is connected to a differentiator 677 in turn connected to a set-reset mechanism 678 itself connected to a memory unit 679 leading to the a port of another and-gate 681.

Port G1 of board G is supplied with A1 pressure air from the circuit controlled by the mode selector valve 337B. The line 643 (Sheet 4) supplies A1 air to a line 682 having a branch 683 (Sheets 8 and 7) from which extends a connector 684 (Sheets 7 and 5). The connector 684 has a branch 686 (Sheet 3) furnishing the A1 air supply to the G1 port of the board G. From the port G1 within the board a branch 687 extends to the b port of the and-gate 676, a branch 688 extends to the b port of the memory unit 679, and a branch 689 extends to the b port of the and-gate 681. With an air signal furnished at the b port of the and-gate 676, when a signal then comes in at port G3, the c port of the and-gate 676 is conditioned to afford a signal through the differentiator 677, the set-reset unit 678, and the memory unit 679 and through the and-gate 681 to a line 691 going to the b port of a not-gate 692 and to the b port of an and-gate 693.

In beginning the automatic cycle, the programmer 660 is intended to start out from its first position with only cam 12 effective upon its associated valve 672-12. However, the programmer may not initially be in Position 1 due to a previous service operation, tampering, initial setup conditions, or the like. When the programmer is out of Position 1, as shown in the diagram, FIG. 41, then in addition to cam 12 being effective, cam 1 is also effective in all positions from 2 to 16, inclusive. When cam 1 is effective, then the corresponding valve 672-1 is no longer in vent position. Valve 672-1, as well as valve 672-2 and valve 672-12, are specially supplied with pressure from the A1 circuit line 643 through th conduit 682 (Sheets 4, 6, 8, 10 and 12). The conductor 682 has a branch 696 (Sheet 12) extending to the vavle 672-12, a branch 697 (Sheet 11) extending to the valve 672-2, and itself terminates at the valve 672-1.

When valve 672-1 is in effective position because cam 669-1 is active, there is flow of A1 air through conduit 682 into a duct 698 which has five branches, one of which is a line 699 extending to the G6 port of the baord G, from which, within the board, a line 701 goes to the a port of the not-gate 692, blocking flow from the c port thereof. From the line 701 a branch 702 goes to the a port of the and-gate 693. Since pressure is already on the port b of the and-gate 693, pressure from the c port thereof is transmitted through a line 703 to the b port of another and-gate 704.

Since the mechanism is just being started, the engine is not revolving and is in "dead" condition. This "dead engine" condition affords air pressure, from a control board later to be described, at port G4 and transmitted through a line 706 to the a port of the and-gate 704. With both b and a ports thereof pressurized, there is an output through a line 707 to port G5. A line 708 extends from port G5 to a "Latched Stop Input-Output" board H (Sheet 5, FIG. 19), being connected at port H7 thereof.

Within the board H a line 709 extends from the port H7 to one input port of an or-gate 711, from the output port of which a line 712 is connected to port H8. A connector 713 goes from port H8 to a "Reset Pulser" board I (FIG. 20, Sheet 6) connecting at port 14. From the port I4 the incoming connector 713 joins one branch 714 going to the b port of a not-gate 716 and another branch 717 going to the b port of another not-gate 718. The c port of the not-gate 716 has a conductor 719 emerging from the board at the port 12. A line 721 from the conductor 719 has one connection to the a port of an or-gate 722, and another connection 723 to the a port of the not-gate 718. From the or-gate 722 there is a connection 724 to a timer 726, the outlet port c of which goes to a conductor 727. One end of the conductor 727 extends to the a port of the not-gate 716, and the other, branched end of the conductor 727 goes to both the b and c ports of a not-gate 728, the a port of which is joined to the c port of a timer 729, the a port of which goes to the c port of the not-gate 718.

With this arrangement, when pressure enters the port I4 and the line 714, air flow continues through the not-gate 716 and the line 719 and out the port I2. Some of that air flow bypasses through the line 721 and the or-gate 722 through the line 724 into the timer 726, in which pressure builds up relatively slowly. When the pressure has built up sufficiently in the timer 726, it is communicated through the conductor 727 to the a port of the not-gate 716, shutting that not-gate off and stopping further flow through the line 719, thus cutting off the outlet of pressure fluid to the port I2 and marking the end of an initial air pulse.

There is also initial flow through the line 717 and the not-gate 718, so that the timer 729 is slowly charged. The rising pressure therein eventually puts the not-gate 728 in condition so that the b and c ports thereof, being connected togetehr by the line 727, exhaust to the atmosphere. This clears the line 727 and removes pressure from the a port of the not-gate 716. When this occurs, flow resumes between the b and c ports thereof and through the line 719 and out the port I2 again, starting a second pulse. Whenever there is pressure in the line 719, such pressure is transmitted through the line 723 to the not-gate 718, turning such gate off and precluding further flow from the port b thereof to the port c thereof and exhausting the timer 729 and the a port of the not-gate 728, the elements thus being restored to their original condition. Since this operation repeats itself indefinitely, a timed succession of spaced air pulses exits from the port I2.

All of the pulses from the port I2 travel through a conductor 731 to a "Downshift-Speed Interlock" board J (FIG. 21, Sheet 10), being connected at port J4 thereof. Within the board J the port J4 is connected by a duct 732 to an or-gate 733, the output of which travels through a duct 734. Part of the flow in the duct 734 will be later described. The part presently traced flows through a not-gate 736 to a line 737 leading through an or-gate 738 to the port J8. The successive pulses from the board I, after going through the board J, are especially conditioned. For that reason, from the port J8 a line 739 is joined to a "Pulse Conditioner" board K (FIG. 22, Sheet 10) at port K7. Within the board K the port K7 is connected through the a port of an or-gate 741 and through a timer 742 to an and-gate 743.

A supply of A1 air is fed to the board K at port K4 by a cnnnector 744 joined to the conduit 682. Within the board K the air supply at port K4 travels through a duct 746 and through a lead 747 to the other input port of the and-gate 743 and also to an input port of an and-gate 748. A lead 749 from the duct 746 goes to the b port of a memory unit 750, and pressure from the c port of the memory unit is effective not only on the other input port of the and-gate 748, but, through a line 751, is passed through a timer 752 to one input port of an and-gate 753, the other input port of which is supplied by a line 754 from the duct 746. Output from the and-gate 753 goes through a set-reset gate 755 to the a port of the memory unit 750, which is under control of the output of the and-gate 743 acting through a differentiator 756. By this means an incoming pulse at port K7 affects the and-gate 743 which, through the differentiator 756, the set-reset gate 755, the memory unit 750, and the feedback through the timer 752 and the and-gate 753, is particularly tailored upon issuance from the and-gate 748. From that point the tailored pulse travels through a line 757 and through a not-gate 758 (connected to receive a signal from a similar, competing board later to be described, the not-gate 758 normally not being inhibited) into a line 759 going to port K5. The pressure pulse continues from port K5 in a line 760 to the downshift cylinder 668 (Sheet 12) of the programmer 660 and therein effectuates a one-step shift in a downward direction; that is to say, from a higher number cam to a lower number cam.

Should the programmer for any reason after such single downshift still be in position so that the No. 1 cam is still effective, according to FIG. 41, the same pulse cycle with a corresponding downshift repeats itself until such time as cam 1 is in Position 1 and so is no longer effective to hold valve 672-1 in shifted position. The spring-restored valve 672 -1 removes pressure from and vents the line 699 from port G6 of the G board and deprives the and-gate 693 and port G5 of that board of the necessary signal for further operation. The programmer 660 is thus brought back from any random or intermediate position to an appropriate position for starting the proper control cycle with the programmer in Postion 1, with cam 669-1 no longer effective, but with cam 669-12 solely effective.

The programmer and board G having thus been corrected (if necessary) to proper starting position, the regular programmed functioning of board G is considered.

The programmer 660 being in Positon 1, cam 1 is not effective, the valve 672-1 is spring-held in vent position, the line 699 is vented, and pressure is not on the a port of the not-gate 692 nor on the a port of the and-gate 693. The not-gate 692 is not inhibited and permits flow from its b port to the c port thereof and thus becomes effective upon an and-gate 761. Cam 12 (669-12) (Sheet 12) being effective in Position 1, which the programmer now occupies, there is pressure flow from the A1 line 682 through the branch 696 and through the shifted valve 672-12 into a line 762 having a branch 763 extending to port G8 of board G. Therein flow is through a lead 764 to the b port of the and-gate 761. With pressure on both of the ports of the and-gate 761, there is pressure in an outlet line 766 therefrom at the port G7, from which flow takes place into a line 767. At one end, line 767 extends to a port L8 of an "Upshift To Position 3 And 4" board L (FIG. 23, Sheet 3). In the board L the entering air goes through a line 768 and an or-gate 769 to a duct 771. This connects to an or-gate 772, from which a passage 773 joins to port L7. A line 776 from port L7 goes to port M8 of a "Pulse Conditiner" board M (FIG. 24, Sheet 10).

The M board at port M8 has a duct 777 leading to an or-gate 778, from which a connector 779 leads through a not-gate 781 to a line 782 and through a timer 783 to a line 784 extending to one inlet port of an and-gate 786. The port M4 is supplied with A1 air from a connector 787 going to the line 682 and furnishes such air through a duct 788 and a line 789 to the and-gate 786, so that pressure travels therefrom to a differentiator 791 and to a set-reset gate 792. From there a signal is imposed upon a memory unit 793 supplied through a duct 794 with A1 air from the line 788 and delivering such air through a connection 796 to an and-gate 797 (to which the A1 air duct 788 is also connected) and to a timer 798, from which a connector 799 goes to one input port of an and-gate 801 also joined to the A1 air supply 788 by a line 802. The output of the and-gate 801 is joined by a duct 803 to the set-reset gate 792.

Thus, when a signal from board G through board L arrives at port M8, the signal travels through the or-gate 778, through the uninhibited not-gate 781, through the timer 783 to the conditioned and-gate 786, from which the signal flows through the differentiator 791, the set-reset unit 792 and the memory 793. The effect is to provide a single pulse at the output of the and-gate 797. This is conveyed through a connector 804 to a not-gate 806 which, if not inhibited, passes the pulse through a line 807 to port M5. Inhibition of the not-gate 806 occurs only upon receipt of a signal on line 760 (Sheet 10) from port K5. Pressure at that point is transferred through a line 808 to the M6 port of board M and from there through a line 809 to the not-gate 806. This locks out an upshift pulse from the port M5 if a downshift signal is simultaneously being supplied at port K5 from the board K. At the time now being described, the programmer is in Position 1, from which there is no downshift. Hence, there is no inhibition through the port M6, and so an upshift pulse leaves the port M5 and travels through a connection 811 to the upshift cylinder 666 and produces an upshift of the programmer from Position 1 to Position 2 thereof and travels through a connection 812 to the set-rest unit 678 in board G (FIG. 18, Sheet 3).

In Position 2, cam 669-1 is active and shifts the valve 672-1 from vent poistion to a position pressurizing the line 698 and its five branches, including line 699. Pressure in line 698 is made effective through line 699 and so upon port G6, as before, and also is made effective upon a line 816 going to port E5 of the "blow-down valve control" Board E.

From this port E5 pressure is conducted through a line 817 to a not-gate 818. The port E4, being supplied with A1 air from a line 680 extending from the branch 683, ordinarily transfers such air through a line 819 and the not-gate 818 to a line 821 joined to the or-gate 561, so as to pressurize the port E2 and so open the blow-down valve 319 through the line 563, but the pressure in line 817 stops such flow at the not-gate 818 so as to prevent opening pressure going to the blow-down valve 319. Pressure in line 817 is also made effective through a line 822 and a connected line 823 on an and-gate 824 connected by a line 825 to the conductor 562, so that when the not-gate 818 is inhibited, the lines 562 and 563 are vented. The line 822 goes to the or-gate 566 and, as previously described and because of the timer 583, affords a set-duration (about 25 seconds) pressure pulse to the port E8, thus briefly pressurizing the line 579 and, through the or-gate 581 and the line 582, briefly opens the purge valve 316 to afford a purge through the open blow-down valve and then permits it to be closed again by its return spring.

When the brief pressurization to open the purge valve has expired and there is no longer any inhibition from the open not-gate 576 on the not-gate 568, pressure again is tranferred from the line 567 through the not-gate 568 and the and-gate 569 to the port E7 and from thence through the line 573 to close the previously open blow-down valve 319. When the valve 319 is closed, an indicator 826 is correspondingly positioned. The indictor is diagrammatically shown as operated according to the blow-down valve position. The indicator includes a valve core 827 adapted to control certain air lines to refelct the blow-down valve position. In the open valve position shown, a supply of main air from the line 342 is delivered to a pipe 828 (Sheet 1) and through a pipe 829 to the indicator 826 and is there blocked since the valve port is simply connected to a display meter 830. When the blow-down valve is closed, the valve core 827 is shifted to connect the pipe 829 to a line 831, so that the line is pressurized and transmits the pressure to a "Permissive Input No. 2" board N (FIG. 25, Sheet 5) at port N4.

Within the board N the port N4 is joined through a duct 832 to an and-gate 833 also joined by a duct 834 at port N5 and a connector 836 to the valve 672-1, which is active since the programmer is in Position 2. The and-gate 833 thus has an output through a duct 837 to an and-gate 838. The other side of the and-gate 838 is joined by a duct 839 at port N6 to a line 841 to the suuply line 426 (Sheet 13). The output of the and-gate 838 travels through a duct 842 to an and-gate 843, the other duct 844 to which is joined to port N8. This, in turn, is connected by a pipe 846 to the output port O8 of a "Cranking Timer" board O (FIG. 26, Sheet 5). Thus, while the board N is conditioned by the verification of closure of the blow-down valve to continue the starting sequence, there must be a further signal from board O, and this in turn, as will appear, depends upon a signal from a "Permissive Input No. 1" board P (FIG. 27, Sheet 3). It will be remembered that there is pressure at port G7 into the line 767 going to the board L and that same pressure is available in another part of the line 767 going to port P7 of board P.

Within board P the prot P7 is connected to a differentiator 847 to which are also connected a battery of accumulators 848 by a lead 849. The output of the differentiator 847 goes through a conductor 851 to one side of an and-gate 852, the other side of which has a duct 853 leading to port P5, from which a line 854 goes to an indicator 856 having a core 857 and representative of the position of the discharge valve 308. When the valve is closed, as shown, air from the line 828 pressurizes the line 854 and under the conditions mentioned gives an output from the and-gate 852 through a line 858 to an and-gate 859. The other input port to the and-gate 859 is connected to port P4 by a duct 861, from which a connector 862 goes to an indicator 863 having a core 864 movable pursuant to the position of the bypass valve 312.

In open position of that valve, as shown, the indicator core 864 conducts air from the line 828 through a pipe 866 into the line 862 and so supplies a signal through the duct 861 to the and-gate 859 to afford an output therefrom through a line 867 to an and-gate 868. A duct 869 connects the gate 868 to port P6, from which a line 871 extends to an indicator 872 haing a core 873 responsive to the suction valve 306. In the valve closed position shown, a connector 874 from the line 828 supplies pressure air through the core 873 to the line 871 and thus energizes the and-gate 868 to afford a signal through a line 876 to another and-gate 877. From the port P3, a line 878 extends to the and-gate 877 and on the other side of the port a connector 879 extends to the port G4 and from thd port Q7 of a "Run-Gas And Dead Engine" board Q (FIG. 28, Sheet 5).

The board Q is supplied with A1 air from the pipe 683 and the line 684 through a connector 881 joined to port Q6. A lead 882 and a line 883 extend to one port of an and-gate 884, while the lead 882 itself is connected to the b port of a not-gate 886 from the c port of which a line 887 goes to another not-gate 888 and from thence through a timer 889 to the other inlet port of the and-gate 884. The outlet of the gate 884 is connected through a lead 891 to an or-gate 892, from which a duct 893 leads through the port Q7 and so pressurizes the line 879 and, at port P3 of the P board, energizes the and-gate 877. This affords an outlet signal through a line 894 to an and-gate 896. The line 684 brings A1 air to port P1 and through a duct 895 enables the and-gate 896 to afford an output signal through a duct 897 to port P2. Thus, a signal at port P2 indicates that the discharge valve 308 is verified as closed, that cam 1 is in position, that the bypass valve 312 is verified as open, that the blow-down valve 319 is verified as closed, that Group I of the shut-down devices 401, etc., is armed, that the suction valve 306 is verified as closed, and, from the board Q, that the engine 326 is not revolving, or is dead, as will later be described.

All of the gas line valve indicators except the blow-down valve 319 and the purge valve 316 have return lines which, if not blocked, do not allow the permissive, engine-start signals just described. For example, the discharge valve indictor 856 has a return line 901 extending to port L5 and if the valve is out of starting poistion; i.e., open, the line 901 is pressurized instead of the line 854, which is vented, thus depriving port P5 of a signal, and there can be no start. Comparably, the blow-down valve indicator 826 if out of position vents the line 831, depriving the port N4 of a signal, and there can be no start. Also, the indicator 863 for the bypass valve has a return line 902 going to a board later to be described and having the same result. In the same fashion, the indicator 872 for the suction valve has a return line 903 going to a board later to be described and producing the desired effect. The purge valve 316, being spring-closed, has no return line.

In this condition of the valves and related structures, a signal at port P2 is transmitted through a line 904 to port O2, through a branch 906 to the or-gate 373 (Sheet 13) to continue the signal thereat, and through a branch 907 to a pressure cell 908 later to be described. The signal at port O2 (FIG. 26) is carried by a duct 909 into a set-reset unit 911 and through a duct 912 into a memory unit 913. There is a supply of A1 air to the port O1 from the line 684 through a pipe 914. A duct 916 leads from the port O1 to and through the memory unit 913, from which flow is into one input of an and-gate 917, the other input of which is supplied by a branch 918 from the duct 916. Thus, an output signal from the and-gate 917 is furnished to the port O8 for transmission through the line 846 to port N8, as previously described. Some of the signal at port O8 is also furnished through a line 919 to a timer 920 connected by a line 921 to a pair of accumulators 922 and 923 and to one side of an and-gate 924. Since the other side of the and-gate input is joined by a line 926 to the A1 air lead 916, the output of the and-gate 924 supplies a timer 927 connected by a line 928 to an or-gate 929, the output of which is connected by a duct to the a port of the set-reset unit 911.

With this mechanism, the signal at port O8 continues until the timer 920 and accumulators 922 and 923 charge fully. This may be about 10 or 15 seconds in a representative case. When there is a full charge thereon, a signal therefrom on the and-gate 924 (already supplied through line 926 with A1 air) sends a signal through the timer 927, the duct 928 and the or-gate 929, and through the line 931 to reset the set-reset unit 911 and stop the signal from port O8. Also, the timed signal from the and-gate 924 is fed through a line 932 to a vented and-gate 933, the other line 934 to which is joined at port O7 by a line 935 to the overcrank shut-down device 401A (Sheet 13) of the Group I shut-down devices. When line 932 pressurizes the and-gate 933 at the end of the timed cranking period, if there has been no engine start, as will later appear, the and-gate 933 vents the line 935 and switches the shut-down unit 401A, venting the line 403 and shutting down the system.

With the board N prepared, as previously described, the receipt of a signal at port N8 gives a similar signal at port N7 to a line 936, one branch of which extends to the cranking gas or-gate 370 and, a before, energizes the cranking gas valve so as to turn the engine for not more than a predetermined time.

Also, the line 936 from port N7 extends to the port R7 of a "Pulser Pressurizer" board R (FIG. 29, Sheet 5). There is a supply of A1 air to the port R1 through a pipe 937 extending from the line 684 and within the board the air pressure is carried by a duct 938 through a not-gate 939 and a line 940 to one inlet of an and-gate 941. The signal at port R7 from line 936 is carried through a duct 942 and through an or-gate 943 to a pipe 944 joined to the other port of the and-gate 941. Thus, unless inhibited at the not-gate 939, a signal at the port R7 produces a signal at port R8. In turn, the signal at port R8 is transmitted by a line 946 through a pressure reducing valve 947 and an orifice 948 to supply low pressure air through a line 949 and a line 950 to a turn pulser 951 on the engine 326.

The turn pulser, diagrammatically shown, is a valve connected to be reciprocated by the turning engine and alternately opening the line 949 and the line 950 to the atmosphere through a duct 945 and blocking such lines, so that pressure builds up repetitively in the line 949 and exhausts, thus forming spaced, low pressure pulses in the line 949. This fluctuating low pressure is felt by a diaphragm-actuated vlave 952 joined to the line 949, the diaphragm and valve following the pressure pulses. The valve 952 itself controls flow from a line 953 joined to the air pressure line 841. High pressure air in the line 953 is supplied to the valve 952 and is also supplied to a pulse counter 954. The outlets of the pulse counter 954 and of the pulse valve 952 are joined to a line 956, so that high pressure pulses from the valve 952, as counted by the pulse counter 954, appear at the port Q2. The pulse counter initially has been reset by pressure in the cell 908 from the lines 907 and 904 leading from port P2. The cell 908 shifts a valve 955 affording pressure from a line 958 joined to the line 937 to do the resetting.

The pulse counter 954 is joined by a line 959 to a port S4 of an "Ignition And Gas Valve Latch" board S (FIG. 30, Sheet 7). Within the board S a duct 960 extends to an or-gate 961 connected to the c port of a set-reset device 962 from the b port of which a connection is made to a memory device 963, the output of which is to the a port of an and-gate 964. A supply of A1 air is furnished by the line 683 to the port S1, from which flow is through a passage 965 to the b port of the and-gate 964. A line 966 extends from the line 468 from the run-gas or-gate 462 (Sheet 4) to the port S6 and by a duct 967 to the or-gate 961, so that either line 959 or line 966 can signalize board S. Thus, a signal at port S4 or port S6 is reproduced at port S2 through a line 968 from the and-gate 964, depending upon the set-reset unit 962. This receives a signal from port S3 through a duct 969 from a line 970 from the line 879 emanating the port Q7 at the time that port also signals ports P3 and G4. The signal at port S2 is transmitted through a line 971 and through a branch 972 to port R3 to maintain the signal at the and-gate 941 and through the line 971 itself to establish a signal on the ignition or-gate 432 (Sheet 4), so that, as before described, the engine is supplied with magneto ignition.

On the engine 326 there is a device (not shown) to observe the fact of an ignition spark being present, and that device, when such spark is observed thereby, sends a signal through a line 973 (Sheet 7) to an actuator of a valve 974 ordinarily vented but when actuated connected to an air supply from the line 683 through a pipe 976 to port S8. Within the S board, the port S8 is joned by a duct 977 to a timer 978 which affords a few seconds delay for safety's sake and then is effective through a line 979 on an and-gate 981 also connected by the line 965 to the A1 air supply, so that upon the verified fact of ignition there is an output from the and-gate 981 through a duct 982 to an and-gate 983 connected to the pressurized line 968 by a duct 980 and joined to the port S7. A line 984 extends from the port S7 to the starting fuel gas or-gate 443. A branch 985 from the line 984 goes to port Q3. With ignition and with starting gas, the revolving engine can begin to operate under its own power.

The engine runs and gradually increases its speed to an appropriate idle speed limited by the amount of starting gas supplied to it. To respond to the engine speed, in addition to the usual engine governor provided, there is connected to the engine a speed responsive device and transmitter 1001 (Sheet 3) connected to the principal air supply line 342 by a line 1002 provided with a pressure reducer 1003. The speed transmitter is effective to send out a signal proportional to some function of the speed of the engine 326 through a line 1004. This line extends (Sheet 5) to the input of relay valve 1006 having an air supply line 1007 joined to the line 841 and providing through an outlet line 1008 a signal proportionate to the signal in the control line 1004. The outlet line 1008 extends to port O5. Within the board O, the port O5 is connected by a duct 1009 to an or-gate 1011 itself joined by a pipe 1012 to the or-gate 929, and so the engine speed factor is impressed through the line 931 as one of the conditions effective to recondition the set-reset unit 911 and deprive the port O8 of a signal. This affects board N at port N8 to stop the signal from port N7 and in the line 936 to shut down the cranking gas or-gate 370, and so discontinue the cranking gas supply. The absence of signal in the line 936 to port R7 also precludes any signal therefrom at port R8 and in the line 946 to suppy the cranking pulse counter.

Further, a connector 1013 to the line 1008 extends to port R2, from which a duct 1014 goes to the not-gate 939 and so stops the supply of A1 air to the port R8, and through the line 946 to the pulse relay valve 952. The line 1008 has a branch 1016 going to port Q4, from which a duct 1017 leads to the b port of an and-gate 1018, the a port of which is joined by a duct 1019 at port Q3 to the line 985. With both signals on the and-gate 1018, there is an output through a line 1021 to port Q5, from which a connector 1022 leads to the running fuel gas or-gate 462 (Sheet 4) and so provides the engine with a generally unrestricted running gas supply.

Within the board Q, the duct 1017 has a branch 1023 going to the not-gate 886 and when energized inhibits flow to the line 887 and so prevents further output from the gate Q7 through line 879. This is of interest as a cancellation of the "dead engine" aspect of board Q, previously referred to as an important factor necessarily present prior to engine cranking. the detailed operation of board Q is somewhat more complex and so is explained in greater detail.

Within the board Q the connection of the line 956 from the pulse relay valve 952 at port Q2 is to a duct 1026 going to the a port of an or-gate 1027. Branched from the duct 1026 is a line 1028 going to the b port of an and-gate 1029. A connector 1031 extends directly between the b port of the or-gate 1027 and the a port of the and-gate 1029. The c port output of the or-gate 1027 is joined by a pipe 1032 to a not-gate 1033 itself at its a port joined to the c port of the and-gate 1029 and having an output connector 1034 going to a memory unit 1036. The memory unit 1036 is supplied by a duct 1037 connected to the lead 887 and affords an output to the line 1038 connected to the a port of the not-gate 888 and also through a line 1039 to a timer 1041. This is connected to the a port of an and-gate 1042, the b port of which is supplied from the line 883 by a branch 1043. The c port output of the and-gate 1042 is sent to the second input port of the or-gate 892 through a line 1044.

In operation, the timer 889 is energized with A1 air through the not-gate 888 and the timer 1041 is energized from the line 1039 pressurized simultaneously with the shut-off at port a of the not-gate 888. The timers 889 and 1041 have the same timing duration and can each operate for a set time period, but they cannot operate together. When the board is first energized, and A1 air from the port Q6 is supplied to both and-gate 884 and and-gate 1042 and through not-gates 886 and 888 to the timer 889, a timing period starts. At the end of the timing period of the timer 889, the pressure therein has had time to build up and spill out, furnishing a dead engine signal at port Q7. But when pulses arrive at port Q2 faster than or within the timing interval of timer 889 or of timer 1041 (the intervals being the same), the timers are each exhausted before they have time to build up pressure, and the dead engine signal at Q7 disappears. If the engine is below idle speed so there is no pressure at port Q4, the first pulse at port Q2 goes through the or-gate 1027 and the not-gate 1033 to the a port of the memory unit 1036 and from the c port thereof and the line 1039 to start the timr 1041.

At the end of the first pulse, the pressure at the a port of the memory unit 1036 is carried back from the port c to port b of the not-gate 1033 and from port c to port b of the or-gate 1027, from which it is transmitted into the a port of the and-gate 1029, wherein the pressure is trapped. The next pulse at port Q2, is forwarded through line 1028 to the b port of the and-gate 1029 and is delivered to the a port of the not-gate 1033, turning that gate off and venting port c thereof. The same, second pulse is also delivered through the or-gate 1027 to the b port of the not-gate 1033 but is there blocked since that gate has just been turned off. The venting of port c of the not-gate 1033 also vents the a port of the memory unit 1036 and so removes the signal from the timer 1041 and stops the operation of that timer. But timing is then initiated in the timer 889 since the signal at the a port of the not-gate 888 has also been vented, and flow is then in through line 887, as before, again starting a timing period in timer 889.

The next, third pulse at port Q2 once again sets the memory unit 1036, thus turning off the timer 889 and restarting a new period in the timer 1041. The described cycle repeats indefinitely so long as pulses at port Q2 are more closely spaced than the time intervals set into the timers 889 and 1041. When the pulses received are more widely spaced, a dead engine signal is afforded. With more rapid engine speed, the signal is cancelled, and when the engine is up to idle speed, the not-gate 886 is turned off and no further dead engine signal is possible. When signals are at ports Q3 and Q4, the run-fuel gas valve is opened, as described.

When the engine has been supplied with adequate running gas and has come up to governed speed, the automatic start portion of the mode two or "automatic start-stop" mode has been accomplished. This mode is not usually selected as an operating mode but is useful in checking the functioning of the engine, for test purposes and for running in. The automatic stop portion of this mode is accomplished when any of the shut-down devices signals trouble, or the main or manual air supply at the A1 air supply are cut off or fail for any reason. A stop can also be effectuated by the attendant returning the mode selector to its off or inactive position by rotating the crank 333. In the foregoing fashion, the "automatic start-stop" mode is accomplished.

The next more nearly fully automatic operating system is turned "automatic start-stop and load." This mode of selected by the attendant turning the crank 333 of the mode selector 331 one more step beyond the "automatic start-stop" position thereof, and so establishes mode three. In this position the cam 334A is not effective, cam 334B remains effective, and cam 334C is moved into effective position. (See FIG. 42) The result of this is that the mechanism, if starting from a complete stop, goes through exactly the same sequences just describd and then continues with further steps, to be described. If the engine is already operating at governed speed and the cank 333 is then advanced by the attendant into he "automatic start-stop and load" position, the sequence then continues from the governed speed engine operation.

Under these conditions, the speed transmitter 1001 has actuated the relay 1006 (Sheet 5) as described, and there is a pressure supply to the line 1008 and also to a branch line 1046 leading to port L3 (Sheet 3). To the branch line 1046 is connected a control line 1047 going to the a port of a not-gate 1048 at its c port opening to atmosphere and at its b port joined by a line 1049 to one of the shut-down indictors 387C (Sheet 13). This shut-down device in Group II is responsive to engine under-speed, and pressure in line 1047 at port a of the not-gate 1048 during normal engine speed operations disconnects the indicator line 1049 from vent. If the engine speed should drop unduly, the not-gate 1048 is no longer inhibited, since the pressure in line 1047 falls accordingly, and vents the shut-down device 387C and so stops the system.

The signal in line 1046 is carried to port L3 and conditions the L board for an upshift. From port L3 flow is through a duct 1051 to the b port of a not-gate 1052 and from the c port thereof through the or-gate 769 and so to the port L7. The a port of the not-gate 1052 is joined by a duct 1053 to the port L2. From this port a line 1054 extends to the valve 672-2, which is vented and is not shifted in Positon 2, since cam 2 is not effective in that position. There is thus no inhibition on the not-gate 1052, so pressure is available at port L7. This pressure is transmitted by the line 776 to port M8 of the pulse conditioner board M, from which at port M5 goes a single pulse through line 811 to energize the cylinder 666 and to give the programmer one upshift from Position 2 to Position 3, in which cams 1, 2 and 12 are effective. (See FIG. 41) The net result is to cause cam 2 to shift valve 672-2 as well as to hold valves 672-1 and 672-12 in shifted position and to supply A1 air from the line 682 to the line 1054, thus activating the not-gate 1052 and stopping the upshift signal.

The shifted valve 672-2 also supplies A1 from pipe 697 to a line 1056 leading to the board D at port D4. From port D4 a line 1030 goes to the or-gate 536 and so sends a signal through the line 537 to port D6. Connected to the line 1030 is a line 1035 going to the a port of a not-gate 1040. A supply of A1 air is received at port D3 through a line 1045 from the line 683 and from the port D3 goes through a duct 1050 to the not-gate 1040. A duct 1055 joins the output of the not-gate 1040 to the or-gate 552. Shunted across the lines 553 and 1030 is a vented and-gate 1060, while shunted across the lines 1055 and 534 is a vented and-gate 1065.

During manual operation when there is no A1 supply of air at port D3, pressure at port D7 acts through the or-gate 552 to pressurize the line 553 and port D8 to close the discharge valve 308 through line 554, and at the same time pressurizes port b of the and-gate 1060 to vent port D6 through the or-gate 536 and relieve the line 538. Similarly, pressure at port D5 acts through the or-gate 536 to pressurize port D6 and through line 538 to open the discharge valve 308, and at the same time pressurizes the and-gate 1065 to vent the line 554 through port D8 and the or-gate 552. In automatic operation when A1 air is available, port D3 is pressurized and through the not-gate 1040 and the or-gate 552 pressurizes the port D8 and the line 554 to urge the dischrage valve closed, at the same time venting the opening line 538 through port D6, the or-gate 536 and the and-gate 1065. When, in automatic operation, cam 2 of the programmer 660 is effective to pressurize line 1056 and port D4, pressure in line 1030 through or-gate 536 and line 537 pressurizes port D6 and line 538 to tend to open the discharge valve. Pressure in line 1030 is transmitted through duct 1035 to inhibit the not-gate 1040, so there is no flow in line 1055, nd such pressure is also made effective upon the and-gate 1060 to vent port D8 and the line 554 to permit the valve-opening pressure to become effective.

The pressure signal at port D4 is thus effective at port D6 and goes through the line 538 to the and-gate 539 and through the line 588 and the not-gate 589 from ports b to c thereof. Pressure then goes through line 591 and the or-gate 581 to line 582, this opening the purge valve 316 (Sheet 1) against is spring. The compressor pipe loop is thus pressurized. The rising pressure therein is transmitted through the conductor 541 to the pressure cell 542 (Sheet 7), wherein the spool 543 is shifted and supplies air from the line 544 through the line 546 to the a port of the not-gate 589, and so stops flow through line 541 and permits the purge valve to be spring-closed after a short open interval.

The same pressure in line 546 that actuated the not-gate 589 to close the purge valve 316 when the compressor loop was brought up to pressure is also effective upon the a port of the and-gate 539. Since the b port of the and-gate 539 is already pressurized by line 538 from port D6, pressure is transmitted by the and-gate through the line 547 to the opening end of the discharge valve actuator 309, and the discharge valve 308 is opened. When the discharge valve is open and connects the portions of the line 303, the corresponding indicator 856 is similarly shifted and so vents line 854 while pressurizing line 901 to send a pressure signal to port L5 (Sheet 3).

Within board L the signal at port L5 is carried by a duct 1057 to the b port of an and-gate 1058, the a port of which is connected by a duct 1059 to port L4 and by a line 1061 and through an orifice unit 1062 to the duct 1051 joined to port L3, which has been pressurized by the engine speed transmitter relay 1006 through the line 1046. This pressure at port L3 acting through the orifice unit 1062 tends to charge the duct 1059, but this duct at port L4 is connected to a line 1063 extending to a valve 1064 spring-pressed into vent position. The valve 1064 is actuated by a temprature cell 1066 and moved from vent position into block position when the lubricating oil in the engine has come up to proper operating temperature. The line 1063 thus would hold pressure when the engine oil is at proper temperature except that there is also a branch line 1067 extending to a valve 1068 normally spring-pressed into vent position. A pressure cell 1069 moves the valve 1068 to block position in response to the presence of A2 air pressure in the cell 1069.

Air under pressure in an A2 system, distinct from the A1 air system, is available when the A2 system is pressurized. This occurs when the mode selector cam 334C displaces the valve 337C and connects the air pressure line 345 to a line 1072 leading to a pressure cell 1073 actuating a valve 1074 normally spring-pressed to connect to a vent line 1076. When pressure is available at initiation of mode three operation, the valve 1074 joins the main pressure line 639 to a branch 1077, pressurizing the shut-down or-gate 380, and to a line 1078 having a connector 1079 (Sheet 6) to the pressure cell 1069, so that the valve 1068 is shifted to block position.

The port L4, no longer being connected to vent and being blocked, permits the duct 1059 in the L board to be charged and a signal supplied to the a port of the and-gate 1058. Consequently, the and-gate 1058 passes the signal from port L5 through a line 1081 to a not-gate 1082. There is at this time no inhibition on the not-gate 1082 since there is no signal at port L6, to which the not-gate is connected by a duct 1083. Port L6 is joined by a line 1084 to a line 1086 going to valve 672-3, but since this valve is not shifted, because cam 3 (669-3) is not active in Position 3, in which the programmer 660 now is, the line 1084 affords no pressure at L6. The signal in board L at the not-gate 1082 is therefore passed through a duct 1087 to the or-gate 772 to pressurize the port L 7 and the line 776. This in turn pressurizes port M8 and, in the fashion previously described, furnishes an up-pulse to the cylinder 666 and so advances the programmer to Position 4.

Prior to the shift to Position 4, while the programmer is still in Position 3, the blow-down valve 319 is in closed position, the bypass valve 312 is in opened position, the suction valve 306 is in closed position, and the discharge valve 308 is in opened position.

In Position 4, cam 3(669-3) moves valve 672-3 into and holds it in shifted position. This valve is supplied with A2 air from the line 1078 and as soon as shifted pressurizes lines 1086 and 1084, thus pressurizing port L6 and causing the not-gate 1082 to stop the upshift signal from continuing to pass into the duct 1087 to the or-gate 772 and appearing at the port L7.

Pressurizing of the line 1086 also pressurizes a line 1091 (Sheet 11), furnishing a signal to port T7 of a "Suction And Bypass Valve Control" board T (FIG. 31, Sheet 8). Within the board T a duct 1092 extends from port T7 to an and-gate 1093 and has a branch 1094 leading through an orifice 1096 to port T8 through a connector 1097. A branch 1098 leads to the other side of the input to the and-gate 1093, from which a line 1099 goes to port T6. A not-gte 1101 is joined to the line 1092 and has an output connector 1102 to an or-gate 1103 connected by a line 1104 to port T5. The a port of the not-gate 1101 is joined to the branch 1098 by a connector 1105.

When pressure is at port T7 and in line 1092, air is transferred through the not-gate 1101 to the line 1102 and through the or-gate 1103 and the duct 1104 to port T5 unless the not-gate 1101 is inhibited. Inhibition thereof is by pressure from line 1092 through the orifice 1096 into the line 1098 and occurs if port T8 is blocked so that pressure in branch 1098 can build up. From the port T8 a connector 1106 extends to a differential pressure valve 1107 (SHEET 1) provided with actuating cells 1108 and 1109. Cell 1108 is connected by a line 1111 to the gas line 314 on the side of the purge valve 316 and of the suction valve 306 remote from the compressor inlet. Cell pressure is augmented by a spring 1112. The cell 1109 is connected by a line 1113 to the line 311 on the side of the valves 306 and 316 adjacent the compressor inlet. The core 1114 of the valve 1107 is either in one position blocking the connector 1106 or in another position opening the connector 1106 to vent. The valve core position depends upon the differential pressure across the valves 306 and 316.

With the core 1114 in vent position opposite to the position illustrated, a signal at port T7 in part leaks through the orifice 1096, but in the main travels through the not-gate 1101 since no pressure can build up in the vented branch 1098 to inhibit that gate. Thus a signal is available through the duct 1102, the or-gate 1103 and the duct 1104 at the port T5. This pressure signal is transmitted from port T5 through a connector 1116 to the port F6. Within the board F the signal at port F6 travels through a line 1117 to the or-gate 598 therein and to the port F4 unless the signal can travel through a shunt path 1118 to an end-gate 1119 open to vent when also provided with a signal through a line 1121 joined to the duct 606. Since the discharge valve 308 is open at this time, there is no signal from port F7 on the and-gate 1119, the line 1118 is in effect blocked, and pressure at the port F4 travels through the line 601 to the closing end of the actuator 313 and starts to move the bypass valve 312 toward its closed position.

As the bypass valve 312 closes partially, it restricts gas flow in the line 311 and increases the pressure in the line 1113. When such increased pressure is sufficient to overcome the spring 1112 and the force of the pressure cell 1108, the valve core 1114 is shifted and blocks the connector 1106. This in turn permits pressure build-up at port T8 and in the line 1098 and so inhibits the not-gate 1101, thus depleting the line 1102 and depriving the port T5 of a signal. This also deprives the ports F6 and F4 of a signal, so that the bypass valve no longer moves toward closed position, but remains in an intermediate position so as to be responsive to and establish a suitable differential pressure across the suction valve 306.

In board T there is a signal at the and-gate 1093 from port T7 and line 1092, and the same pressue build-up in branch 1098 that inhibits the not-gate 1101 also furnishes the other signal to the and-gate 1093 to provide an output through line 1099 at port T6. This port is joined by a line 1122 to port C4, from which the signal travels through a duct 1123 to the or-gate 519 and through a branch 1124 to inhibit a not-gate 1126 in a line 1127 from port C3 and connected by a line 1128 to the or-gate 526. The port C3 is provided with A2 air through a line 1129 connected to the A2 supply line 1078, so that when a signal is present at C4, the not-gate 1126 is inhibited and A2 air is no longer supplied through the line 1128 to the or-gate 526 nor through a connected line 1131 to an and-gate 1132 connected to vent. The and-gate 1132 also has a connection 1133 to the line 518. The net result is that no signal is present at port C8 to close the suction valve through line 523, but the signal at port C4 is transmitted through the or-gate 519 to appear at port C6 and to pressurize the line 522 to open the suction valve 306.

When the suction valve is open, the suction valve indicator core 873 is shifted from the position shown and pressurizes the line 903 and a line 1130 connected thereto to supply a signal to a pressure cell 1134 (Sheet 8). When pressurized, the cell 1134 shifts a valve 1136 from vent position to a position connecting a duct 1137 joined to the A2 supply line 1078 to a line 1138 extending to port T4. The A2 air supplied to port T4 flows through a line 1141 to the or-gate 1103 and supplies a signal at port T5. Flow is then through line 1116 to port F6 and through the F board to port F4, so that the resulting pressure in line 701 and on the closing portion of the actuator 313 (sheet 1) finishes closing the bypass valve 312.

At this time the engine 326 and the compressor 304 are running, the discharge valve 308 is open, the suction valve 306 is open, and the bypass valve 312 is closed. Gas is therefore being pumped from the line 301 to the line 303, and the engine-compressor unit has been automatically loaded. Thus the mode three "automatic load" function has been accomplished. That is, the engine and the compressor have been automatically set into operation and the various gas line valves have been properly and automatically put into position for gas pumping by the compressor and by the so-loaded engine.

There is a further available refinement to the automatic operaton; that is, operation in mode four, referred to as "automatic load and load adjust." In this mode, variations in the duty of the compressor are responded to automatically by variations in the compressor clearance volume, and variations in the engine load and speed. As before, to operate in this mode, the attendant rotates the crank 333, rotating the shaft 332 to bring the cam 334D into effect and shifting the valve 337D. (See FIG. 42) This puts pressure from line 346 on a previously vented line 1151 (FIG. 4) and forces a pressure cell 1152 to shift a valve 1153 to provide source air from the line 639 to a duct 1154 forming part of an A3 air system. The duct 1154 is joined to an A3 manifold 1156.

In the mode four operation, and when the bypass valve 312 is fully closed, the indicator 863 gives a pressure signal through line 902 to port T2 (Sheet 8). Within board T, the port T2 is joined by a duct 1157 to a timer 1158, itself connected to a line 1159, to which a number of accumulators 1161 are attached and connected to and-gate 1162. A duct 1163 joins the line 1141 to the other input port of the and-gate 1162. When the suction valve 306 achieves fully open position, a pressure is supplied to the line 1141 and through the duct 1163 to the and-gate 1162. Upon appearance of pressure at port T2 when the bypass valve 312 achieves full closure, the pressure appears in duct 1157. After some delay to permit the compressor and engine to accommodate to their new load, a delay time established by the timer 1158 and charging of the accumulators 1161, the pressure in duct 1157 is effective upon the and-gate 1162 to provide a signal at port T3.

From port T3 a line 1167 extends to a pressure cell 1168 (Sheet 9), and the signal from port T3 causes the cell to shift a valve 1169 and so connect A3 air from a duct 1171 (joined to the line 1156) to a line 1172.

The line 1172 has a regulator 1173 therein settable to any desired or nominal pressure serving as a standard for the output of the compressor. This set presusre is delivered through a line 1174 having branches going to a pair of spring-pressed relay valves 1176 and 1177. To supply the relays 1176 and 1177 with values representing the actual compressor outlet pressure, the line 541 (Sheet 7) has an extension 1178 going to a transducer 1179 (Sheet 9) supplied with A3 air from the line 1171 through a line 1181 including a pressure reducer 1182 and connected to a manifold 1183.

The transducer takes air from the manifold 1183 through a duct 1184 and modulates such supplied air in accordance with the instantaneous compressor output pressure furnished by the line 1178. Thus, the output from the transducer furnished to a line 1186 and a branch 1187 reflects the compressor output pressure and is supplied to both relay valves 1176 and 1177. These valves, in turn, are supplied with operating air from the manifold 1183 through a branched line 1188. One relay 1176 has an output line 1189 going to a pressure cell 1191 on one side of a pressure diaphragm 1192, while the other relay 1177 has an output line 1193 going to a pessure cell 1194 on the other side of the diaphragm 1192. The diaphragm controls the spools of a pair of spring-returned valves 1196 and 1197 normally in vent position but shiftable individually. Each valve is supplied with A3 air through a branched pipe 1198 connected to the line 1156.

When the pressure in the line 1178 is high, reflecting a high compressor output pressure, the relay valve 1176 shifts and pressurizes the cell 1191 to shift the valve 1197, and so supplies A3 air through a line 1199 to port U8 of a "BMEP And Differential Pressure Interlock" board U (FIG. 32, Sheet 9). When the compressor output pressure is low, the transducer output pressure in the lines 1186 and 1187 is correspondingly lower than the set pressure in the line 1174, and so the relay 1177 through the line 1193 operates the diaphragm 1192 to shift the valve 1196 and through the line 1198 furnishes A3 air to a line 1201 going to port U4 of board U.

In a somewhat parallel fashion, there is provided an arrangement responsive to an approximation of the brake mean effective pressure (BMEP) of the engine. For this reason, the manifold 1183 has a branch 1202 going to the s port of a computing relay or spring-pressed regulator 1203 (FIG. 9). A signal from the engine speed transmitter 1001 (Sheet 3) is carried by a line 1204 to port 2 of the regulator 1203. Ports 1 and 3 of the regulator are subjected to the pressure of the fuel manifold on the engine through a branched line 1206. The regulator adds the pressures in ports 1 and 3 and subtracts the pressure in port 2 and includes in the result the spring pressure, so as to afford in a branched output line 1207 a modulation of the pressure in port s and corresponding quite closely to the actual BMEP of the engine at any moment.

The line 1207 extends to a pair of relay valves 1208 and 1209. These are supplied with a predetermined value or set signal for BMEP through a branched line 1211 joined to the A3 line 108 through an adjustable regulator 1212. The relays 1208 and 1209 are supplied with operating air trhough branches of the line 1188. When the BMEP is below the set value, the relay 1208 is actuated and supplies pressure through a line 1213 to a pressure cell 1214 at one side of a diaphragm 1216. When the BMEP is above the set value, the relay 1209 is actuated and supplies pressure through a line 1217 to a cell 1218 at the other side of the diaphragm.

The cell 1218 when pressurized shifts a spring-returned valve 1219 and so supplies A3 pressure to a previously vented line 1221 from a connector 1222. To line 1156. The line 1221 has brnaches but itself extends to port U5 of board U. The cell 1214 when pressurized shifts a spring-return valve 1223. This is supplied with A3 air from the line 1156 through a pipe 1224 and when shifted pressurizes a line 1226 going to port V6 of an "Upshift-speed Interlock" board V (FIG. 33, Sheet 10). By thse means, singals are available depending upon the engine speed and gas manifold pressure, representing the BMEP, and from the compressor discharge pressure, and these signals indicate values above or below set values.

Consider the board U when the compressor discharge pressure is low and so there is a raise signal which has shifted valve 1197 through line 1201 has pressurized port U. Within board U the port U4 is connected through a duct 1227 and thorugh a not-gate 1228 to a line 1229 extending to one input port of an and-gate 1231. The not-gate 1228 is not inhibited at this time since the BMEP is not high, so there is no signal in line 1221 from the valve 1219, and so no signal at port U5. Whether or not the and-gate 1231 can function depends upon a signal at the other input port thereof from port U2 through a line 1232. Leading to port U2 is a line 1233 going to a device sensitive to the pressure difference between the compressor inlet and the compressor discharge.

This device (Sheet 1) has one pressure cell 1234 joined by a line 1236 to the compressor suction and has another pressure cell 1237 joined by a line 1238 and a line 541 to the compressor discharge. Between the cells 1234 and 1237 is a spring-pressed valve spool 1239 normally in blocked position for line 1233. When subjected to a differential pressure greater than a selected or predetermined pressure, the valve spool 1239 is shifted and connects the line 1233 to vent, thus precluding pressure at port U2 and preventing the and-gate 1231 from having an output. But with the valve 1239 blocking the line 1233 during normal compressor differential pressure, the port U2 is pressurized and so is the and-gate 1231. The signal from the port U4 to raise the pressure is then passed through the and-gate 1231 and a duct 1241 to the port U1, and from there through a connector 1242 to a port W5 on a "Raise-Lower Pulser" board W (FIG. 34, Sheet 10).

Within the board W the raise signal at port W5 from line 1242 and the board U is passed through a duct 1243 to an or-gate 1244 and through a line 1246 to an and-gate 1247. From the or-gate 1244 a line 1248 extends and has a branch 1249 extending to a not-gate 1251 which, if not inhibited passes the signal through a connector 1252 and a branch 1253 to the and-gate 1247. From there, both sides of the and-gate being effective, an output signal travels in a line 1254 to port W2. Now, when the line 1248 is pressurized, one inlet of an and-gate 1256 is also pressurized. Also, when a singal enters the line 1252, a branch 1257 pressurizes one side of an and-gate 1258, the other sie of which receives a signal from line 1252 and through a timer 1259.

When doubly signallized, the and-gate 1258 passes a signal through a line 1261 to a set-reset unit 1262 connected to a memory unit 1263 joind to the other input of the and-gate 1256 by a line 1264. When so applied, the and-gate 1256 affords an output through a connector 1266 to the not-gate 1251, turning it off and preventing further passng of a signal to the and-gate 1247 and the port W2. When pressurized, the connecor 1266 supplies one side of an and-gate 1267 throgh a duct 1268 and supplies the other side of the and-gate 1267 through a timer 1269, the output duct 1271 from which has leads 1272 and 1273 extending to accumulators 1274 and 1276. The output line 1277 from the and-gate 1267 goes to the set-reset unit 1262. The effect of this board W is to provide a timed series of spaced, output pulses at the port W2 as long as there is pressure at port W5.

An output pulse at port W2 is carried by a line 1278 to port V4, the board V already having a low BMEP singal at port V6 thereof from the valve 1223 through the line 1226 as previously described. The signal at port V4 enters an or-gate 1279 through a duct 1281 and travels into a line 1282 leading to an input of an and-gate 1283. A branch 1284 from the line 1282 extends to a not-gate 1286 having an outlet 1287 extending to an or-gate 1288, from which a duct 1289 connects to the and-gate 1283. The line 1282 also has a branch 1291 extending to a not-gate 1292, the output of which is connected by a line 1293 to an and-gate 1924 having an outlet duct 1296 extending to port V7. From the port V6 a line 1297 extends to the not-gate 1286 and through a branch 1298 to the and-gate 1294.

The described automatic sinal at port V4 passes through the or-gate 1279 and for manual control a manual raise-load signal simlarly can be furnished the or-gate 1279 through a duct 1301 from port V5. A line 1302 leads from port V5 to a manually operated, spring-returned valve 1303 (Sheet 4) which is normally in vent position. When the leave valve 1303 is displaced, it connects the line 1302 to a branch 1304 of the A3 line 1156. Whether a manual or an automatic raise signal is received by the or-gate 1279 in board V, it is passed into the line 1282 and through the line 1291 and the not-gate 1292 to the and-gate 1294. The low BMEP signal from port V6 travels through the line 1297 and the line 1298, so the and-gate 194 pressurizes the line 1296 and affords an output signal at port V7. At the same time, the signal in the line 1297 inhibits the not-gate 1286, so no signal from the line 1282 and the duct 1284 travels through the line 1287 and the or-gate 1288 to the and-gate 1283 and the port V8.

From the port V7 a line 1306 connects to port M7 in board M (Sheet 10), wherein, as previously described, the received signal at M7 produces an up-pulse at port M5, and so energizes the cylinder 666 to move the programmer 660 one step up from Position 4 (cam 3) to Position 5 (cams 1, 2, 3 and 4, but not cam 12). In the foregoing, if the BMEP had been high, not only would there have been a signal from valve 1219 through line 1221 at port U5 to inhibit the not-gate 1228 and so prevent an upshift, but there would also have been an absence of signal from valve 1223 through line 1226 at port V6, so the and-gate 1294 could provide no output.

When the programmer shifts to Position 5 and moves cam 4 to shift valve 672-4, A3 air is supplied from the line 1156 through the valve 672-4 to a manifold 1307 having a line 1308 going to the or-gate 631 (duplicated on Sheets 2 and 11), from which the line 632 affords pressure to close the valve 323 of the No. 1 crank-end pocket 322, thus adding an increment to the gas discharge pressure and to the BMEP.

Now, if the conditions of low BMEP and low gas discharge pressure still persist, another pulse from the board W is similarly induced and produces a comparable result; that is, another upshift impulse to the programmer cylinder 666 and a shift from Position 5 to Position 6. In this latter position, cam 5 becomes effective to shift a valve 672-5 and so to connect a branch 1309 of the manifold 1156 to a line 1310 extending to an or-gate 1311 (Sheets 2 and 11) and so actuates a mechanism (not illustrated, but comparable to that for the No. 1 carnk-end pocket 322) to close off crank-end pocket No. 2. This, in turn, produces an increase in the gas discharge pressure and in the BMEP. If the BMEP is still below set value and the gas discharge pressure is also below the set value, the operation repeats the next upshift of the programmer to Position 7 moves cam 6 to shift valve 672-6. This connects a branch 1312 of the manifold 1156 to a line 1313 going to an or-gate 1314 (Sheets 2 and 11) closing The No. 3 crank-end pocket.

Again, with low BMEP and gas discharge pressure, another upshift to Position 8 occurs, the cam 7 moving a valve 672-7 and connecting a branch 1316 of the manifold 1156 to a line 1317 going to an or-gate 1318 for closing the No. 4 crank-end pocket. This pocket is unique in that it has only half the volume of each of the other pockets. While closure of any one of the other pockets decreases the compressor volume one full increment, closure of crank-end pocket No. 4 decreases the compressor volume but one-half an increment. Increasing the compressor loading one full increment at a time is permissible during the initial load increase, but it is preferred during the latter part of the compressor loading to increase by one-half an increment at a time. This is accomplished by alternately opening and closing pocket crank-end No. 4 as other pockets are closed, all as illustrated in FIG. 41.

For example, the set values not having been reached, the next upshift of the programmer 660 is from Position 8 to Position 9, activating cam 8 and valve 672-8. The effect is to connect a branch 1321 of the manifold 1156 to a line 1322 going to an or-gate 1323 for the No. 1 head-end pocket. During the upshift and the activation of valve 672-8, the valve 672-7, previously effective, is spring-returned to ineffective position since cam 7 is so contoured. This opens the half-size, No. 4 crank-end pocket. Closing No. 1, No. 2 and No. 3 crank-end pockets has afforded three full steps of compressor volume reduction. Closing No. 4 crank-end pocket has afforded a half-step reduction, making a total of 31/2 steps of such reduction. Closing the No. 1 head-end pocket affords a full step reduction in itself, making 41/2 steps, but the No. 4 crank-end pocket being again opened at the same time makes the increment only a half step, so that the total is four steps.

On the nest upshift from Position 9 to Position 10, the valve 672-8 remains shifted and holds The No. 1 head-end pocket closed, but the cam 7 again shifts the valve 672-7 to effective position and recloses the half-size No. 4 crank-end pocket, so the total closure is 41/2 steps or increments.

The upshift from Position 10 to Position 11 activates cam 9 (leaving cam 8 and valve 672-8 activated, but again deactivating valve 672-7), and so activates valve 672-9 to connect a branch 1324 to a line 1326 going to an or-gate 1327 for the No. 2 head-end pocket and providing 5 full closure increments. Similarly, in Position 12 a connection is made from a branch 1328 to a line 1329 going to an or-gate 1331 for the No. 3 head-end pocket and affording 51/2 closure increments. In Position 13, valve 672-10 also becomes effective but valve 672-7 is de-energized, so that there are 6 closure increments.

The upshift to Position 14 leaves valve 672-10 effective and again energizes valve 672-7 to provide 61/2 closure increments. The next upshift to Position 15 shifts valve 672-11 and connects a branch 1332 of the manifold 1156 to a line 1333 going to an or-gate 1334 and effective to close the No. 4 head-end pocket, but at the same time valve 672-7 is de-energized to open the No. 4 crank-end pocket and so affords a closure of 7 increments. The upshift to Position 16 leaves all the valves as before, except that valve 672-7 is reclosed to provide 71/2 closure increments, the maximum. With each pocket closure, the gas discharge pressure and the BMEP are increased.

In programmer Position 16, all of the valves 672 are active, all of the compressor pockets are closed, and the only way to increase output further is to increase the engine speed up to its maximum limit, it being preferred to decrease the compressor volume as much as possible before increasing engine speed. In Position 16, cam 7 has shifted valve 672-7 and has pressurized the or-gate 1318 through a line 1317 and has also pressurized a connected line 1336 extending to port V2 (Sheet 10). Also, in Position 16 cam 11 has shifted valve 672-11 and not only has pressurized line 1133 but also has pressurized a line 1337 extending to port V3. When these two ports are active, pressure is carried in board V through ducts 1338 and 1339 to an and-gate 1341, which consequently provides a signal in a line 1342 having a branch 1343 to the not-gate 1292, and so inhibits output therefrom to prevent any further signals from port V7 and any further upshift pulses. The signal in line 1342 passes through the or-gate 1288 and into the and-gate 1283. There is still a signal at port V4 to increase the load, and this is carried through the or-gate 1279 and the line 1282 to the and-gate 1283. The result is a signal through a duct 1344 to port U8.

A line 1346 leads from port V8 to port X4 of a "Speed Control" board X (FIG. 35, Sheet 9). This board at port X1 is supplied with air from the line 421 through a branch 1347 having a pressure reducer 1348 in it supplying to port X1 air at a pressure (in this case) of 12 p.s.i. Within the board X the port X1 is connected to an or-gate 1349 by a duct 1351. The or-gate is used as a check valve and so has its second input blocked. The outlet from the or-gate 1349 feeds a line 1352 extending to port relatively and has a manifold 1353 connected thereto and going to port X2, to which an accumulator 1354 is joined by a pipe 1356. Assuming for a moment that line 1352 is not vented, the supply of 12 p.s.i. air from port X1 charges the accumulator 1354 with air at that pressure through the mainfold 1353. Since the relative high pressure raise-load pulses from board W are still coming through board V and line 1346 to port X4, they travel in board X through a duct 1357 to a not-gate 1358, which, if not inhibited, passes the signal through a line 1359 to an or-gate 1361 acting as a check valve and so have its other entrance blocked. From the or-gate flow is through a duct 1362 and an orifice unit 1363 to the manifold 1353. Each incoming high pressure pulse at port X4 thus travels through the not-gate 1358, the or-gate 1361, and the orifice unit 1363 to the manifold 1353 and the accumulator 1354, and so raises the pressure therein by 1 increment per pulse above the basic 12 p.s.i. pressure.

Port X3 is thus subject to a minimum or basic pressure and to higher pressure on an ascending scale governed by the number of pulses received at port X4. This pressure variation is used to provide a corresponding engine speed variation. From port X3 a line 1364 extends to a control port of a pressure dividing relay 1366 (Sheet 9) having a divider of four in this case. The relay is supplied with air (at a out 20 p.s.i.) through the line 1183 and discharges air into a line 1367 at a pressure one-fourth that in the line 1364 at the control port. The standard governor (not shown) for the engine 326 operates at a pressure of 3 p.s.i. to hold 400 r.p.m. of the engine and up to a pressure of 15 p.s.i. for an engine maximum speed of 600 r.p.m. Thus, at the datum pressure of 12 p.s.i. in the line 1364, the line 1367 has a corresponding pressure of 3 p.s.i. and the engine governed speed is then 400 r.p.m. As the pulses into board X increase the pressure at port X5, and correspondingly in line 1364, the governor pressure and the engine speed are proportionately increased.

The pressure in line 1367 is transmitted to a selector valve 1368 (Sheet 8). In the position shown, the selector valve furnishes air from the line 421 through a branch 1369 and a manually adjustable pressure reducer 1371 to a line 1372 going to the governor, a pressure gauge 1373 being supplied, so that the attendant by adjusting the reducer 1371 and watching the gauge 1373 can manually set the governor to the desired pressure and corresponding engine speed.

In the manually shifted or "automatic" position of the selector valve 1368, the pressure in line 1367 is supplied to the governor. The net result is that the load raise pulses raise the governing air pressure step by step and increase the engine speed up to the system maximum. And this operation continues indefinitely, subject only to changing conditions or manual override.

Should the load on the compressor and engine be decreased, the foregoing sequence is substantially reversed to relieve the load until a new acceptable lower load is attained. For example, if the compressor discharge pressure is too high, or substantially exceeds the set or selected discharge pressure, then the actual discharge pressure in the line 1178 affects the transducer 1179 so that the relay 1176 compares such high pressure to the set pressure in the line 1174 and provides a signal in the line 1189 to flex the diaphragm 1192 and shift the valve 1197 to connect the A3 pressure line 1198 to the output line 1199, and so pressurizes port U8. The valve 1196 at the same time is spring-returned to vent line 1201. This change vents port U4 and so stops any signal at port U1 and at port W5 to activate board W to issue a raise pulse.

Within board U, the port U8 is joined by a duct 1376 to an or-gate 1377 connected to port U6. From this port a line 1378 leads to port W4, from which a lead 1379 goes to the or-gate 1244 and so energizes the pulser circuit in the board W, as before, to furnish a series of individual pulses. These pulses go to one input only of the and-gate 1247, as before, but this and-gate is no longer effective because no signal is available from port W5 since line 1242 is vented. The pulses also go to an and-gate 1381 through the line 1252 connecting the gates 1247 and 1381 in parallel. The new incoming signal in line 1379 at port W4 is imposed on the and-gate 1381 through a connecting line 1382 and releases a pulse from the and-gate 1381 through a duct 1383 to port W3. This lowering pulse is carried by a line 1384 to port J1.

In board J a connection 1386 from port J1 goes to an or-gate 1387 which is also connected by a line 1388 to port J2, from which a connector 1389 goes to a manual valve 1391 (Sheet 4). This is normally vented but when manually depressed joins the connector 1389 to a branch 1392 of the A3 air line 1156 and so pressurizes the port J2 and the or-gate 1387. The or-gate 1387 thus passes an automatic or a manual lowering signal through a line 1393 to an and-gate 1394, the other input to which is connected by a duct 1396 to port J3. A line 1397 therefrom goes to line 1307 (Sheet 11) pressurized by the open valve 672-4 since cam 4 is effective in Position 16, in which the programmer 660 presently is. This pressure from line 1397 on the and-gate 1394 permits the gate to pass the signal in line 1393 through a duct 1398 to the or-gate 733 and thence to the line 734.

As previously described, the line 734 leads to the not-gate 736 and would now afford a signal at port 739, but at this time the not-gate 736 is inhibited through a line 1399 going to port J7. A connector 1401 therefrom extends to a valve 1402 (Sheet 10) urged into vented position by a spring that presently is overcome by pressure in a cell 1403, the valve 1402 when shifted by the cell being supplied with A3 air from line 1156 by a duct 1404. The pressure cell is energized through a line 1405 going to the line 1367 that carries the modulated pressure regulating the speed control of the engine governor. Since this governor controlling pressure is supplied during this automaic mode of operation, the pressure cell 1403 shifts the valve 1402 to pressurize port J7 with A3 air and so to inhibit the not-gate 736 and prevents an output through line 737 at port J8.

However, the signal in line 734 is also supplied to an and-gate 1406 through a duct 1407 and to a not-gate 1408. Affecting both gates 1406 and 1408 is pressure in a line 1409 going from port J5 directly to the not-gate and having a branch 1411 to the and-gate. A connector 1412 goes from port J5 and joins the line 1221 at the BMEP control (Sheet 9). At this time the BMEP remains satisfactory and does not demand a change. Consequently, the diaphragm 1216 is a neutral position, and the valve 1219 is not shifted but is in its normal, vent position. The lines 1221 and 1412 are thus vented. The vented line 1412 provides no pressure signal at port J5, and although the and-gate 1406 is consequently ineffective, the not-gate 1408 is not inhibited. As a result, the signal in line 734 appears at port J6, from which it travels through a connection 1413 to port X5 (Sheet 9).

This port, X5, has a connection by a duct 1414 to one input of an and-gate 1416 connected at its output to vent and at its other input connected by a line 1417 through an orifice 1418 and a duct 1419 to the accumulator line 1353. The pulse from port W3 of board W through board J thus affects port X5 of the board X and affects the and-gate 1416 to release or vent one increment of air pressure from the accumulator 1354 and the connected volumes, including the line 1364 at port X3. The relay 1366 correspondingly drops the pressure in the line 1367 to the governor and so slows the engine down one increment per pulse. A succession of lowering pulses from board W continues as long as there is a signal at port W4. In this way the engine and compressor speed is decreased in steps until there is a corresponding pressure drop at the pressure input 1178 to the transducer 1179 and the relay 1176 reverts to normal position, thus again centering the diagram 1192 and venting the line 1199, and so stopping further lowering signals.

Should the BMEP remain high after the described compressor discharge pressure reduction by engine speed reduction, there is further compensation. The BMEP signal from the computing relay 1203, being higher than the set signal in the line 1211 (Sheet 9), produces a shift in the relay 1209 and a signal in line 1217 to deflect the diaphragm 1216 to shift the valve 1219, thus connecting duct 1222 to line 1221. This does several things. Line 1221 itself goes to port U5. Within board U, a duct 1421 from port U5 inhibits the not-gate 1228 and prevents an upshift signal from port U1 through line 1242 to port W5. From line 1421 a branch 1422 goes to an or-gate 1423, the outlet 1424 from which goes to the or-gate 1377 to furnish a signal at port U6.

The line 1378 from port U6 energizes port W4 so that, as previously described, a downshift pulse is available at port W3 thereof. The line 1384 carries the pulse to port J1 and through the or-gate 1387 to the and-gate 1394. The other side of the and-gate 1394 is pressurized from port J3 since cam 4 is still active. Thus, the and-gate 1394 sends the signal through the or-gate 733 to the and-gate 1406, also energized from port J5. This is connected to pressurized line 1221 through the line 1412, so the and-gate 1406 affords a signal through or-gate 738 to port J8 and, through line 739 extending therefrom, to port K7. The board K is consequently energized, as previously described, and provides at port K5 a pulse going through line 760 and affecting the cylinder 668 to afford a downshift of the programmer 660.

The downshift is from programmer Position 16 to Position 15, thus inactivating cam 7 (FIG. 41) the No. through the line 1317 opening the 4 crank-end half-pocket. Also, since the valve 672-7 is thus vented, the line 1336 is itself vented and vents port V2. This removes a signal from one side of the and-gate 1341 and so stops that source of signal to port V8. If the conditions that initiated a downshift still persist, the next pulse from board W shifts the programmer from Position 15 to Position 14, in which cam 11 becomes ineffective and valve 672-11 moves to vent position. This not only vents line 1133 to open the No. 4 head-end pocket, but also vents line 1337 and its connected port V3, inactivating the and-gate 1341. If there is further requirement for downshifting, each further pulse from board W produces one such downshift, moving the programmer 660 progressively from Position 14 to Position 13, in which cam 7 again drops out, to Position 12, in which cam 7 is reinstated and cam 10 drops out and opens the No. 3 head-end pocket. From Position 12 the downshift is next to Position 11, in which cam 9 is still effective but cam 7 becomes ineffective, as before. From Position 11 the shift to Position 10 restores cam 7 but inactivates cam 9 and valve 672-9, so that the No. 2 head-end pocket is opened. In Position 9, cam 7 is again ineffective but cam 8 continues in effect, to become ineffective itself in Position 8, in which all of the head-end pockets have been opened.

From Position 8 the shift is to Position 7, in which cam 6 is the highest number cam effective, cam 7 having vented valve 672-7 and so having opened the No. 4 crank-end pocket. The shift from Position 7 to Position 6 removes cam 6 from effectiveness and through the line 1313 opens the No. 3 crank-end pocket. The next downshift is to Position 5, in which cam 5 and valve 672-5 are ineffective and the No. 2 crank-end pocket is opened, and in which cam 4 is effective.

Whenever cam 4 is effective, the corresponding valve 672-4 is also made effective. Pressure in line 1308 not only closes the No. 1 crank-end pocket, but pressure in line 1397 pressurizes port J3 and also pressure in a line 1426 pressurizes port H6 (Sheet 5). In board H the port H6 is joined by a duct 1427 to an and-gate 1428 having its outlet duct 1429 extending to the or-gate 711 and so to port H8. The other input to the and-gate 1428 is thorugh a duct 1431 to port H5, which receives a signal through a line 1432 joined to the output port Y2 of a "Latched Stop" board Y (FIG. 36, Sheet 6). This board Y receives A1 air at port Y1 through a conductor 1433 joined to the line 682 and also receives a signal at port Y3 through a line 1434 supplied from the line 698 controlled by presently effective valve 672-1.

Within board Y and A1 air from port Y1 travels through a duct 1436 to one side of an and-gate 1437 connected to port Y2. A branch 1438 goes through a not-gate 1439 to a line 1441 to a set-reset unit 1442 supplied from a differentiator 1443. This in turn is supplied from an and-gate 1444 joined to the port Y6 by a duct 1446 and connected to the A1 air duct by a line 1447. Beyond the set-reset unit 1442 is a memory unit 1448 fed by a duct 1449 from the line 1436 and joined by a duct 1451 to the and-gate 1437.

In operation, the board Y is effective to supply A1 air to one input of the and-gate 1437 through the line 1436. A1 air also goes through the not-gate 1439 and the line 1441 to the set-reset unit 1442 and through the line 1449 to the memory unit 1448 and through the duct 1451 to the other side of the and-gate 1437. Under these conditions A1 air goes from port Y1 to port Y2 and through the line 1432 to port H5, and thence through the or-gate 711 to afford a signal at port H8, and from there on through line 713 as previously described.

Now, when the programmer shifts down one more step from Position 5 to Position 4, cam 4 and valve 672-4 are inactivated and all three lines 1308, 1397 and 1426 are vented, thus opening the No. 1 crank-end pocket, depriving port H6 of pressure, so that signals previously received at port H5 from port Y2 of board Y are no longer supplied to port H8 from this source, and also depriving port J3 of signals and thus isolating this source of signals to ports J6 and J8. The venting of valve 672-4 also inactivates the last programmer valve connected to the A3 air system. Furthermore, the shift into Position 4 makes cam 12 active and valve 672-12 is shifted from vent to active position. In sum, cams 4 to 11, inclusive, and their respective valves are not longer effective, but cams 1, 2, 3 and 12 and their corresponding valves are active.

The programmer need not go through the entire downshift cycle to open all of the compressor pockets successively if the conditions change. At any time there is only sufficient downshifting to satisfy the current conditions. If, for example, conditions alter to require upshifting because the diaphragms 1192 and 1216 have changed position in response to new requirements, then the programmer will accordingly upshift, as previously described, through one or more steps, and the compressor pockets will accordingly be closed. In short, as the load requirements vary up or down under operating conditions, the programmer automatically loads and unloads the compressor and corespondingly the engine load is increased or decreased; i.e., adjusted.

There are certain conditions which are considered extraordinary and which produce corresponding corrective or responsive actions. For example, suppose that at any time and for any reason the differential pressure across the compressor becomes excessive; that is, the discharge pressure and the suction pressure are farther apart than the design contemplates and might if continued cause trouble. The normally blocked valve 1239 (Sheet 1) is immediately shifted by an excessive difference in pressure between the cells 1234 and 1237 and in moving against the balance spring immediately unblocks line 1233 and connects that line to vent. Venting of the line 1233, among other things, vents port U2 at board U and so stops signals from port U1 to port W5, and so from port W2, thus precluding any upshift of the programmer 660.

The venting of line 1233 produces another effect. Vented in parallel with the port U2 is a port Z7 of a "High BMEP -- High Differential Pressure Shut-down Selector" board Z (FIG. 37, Sheet 13). This is accomplished through a line 1456 joined to the line 1233. At the board Z, port Z8 is connected by a line 1457 to the high differential pressure shut-down device 388 (Sheet 13) and within the board Z the port Z8 is joined by a line 1458 to a not-gate 1459 which, if not inhibited, permits flow through a duct 1461 to an or-gate 1462, acting as a check valve, and connected to a manifold 1463 extending to port Z2. From the port Z7 a line 1464 goes to the a port of the not-gate 1459 and has a branch 1466 to one input to an and-gate 1467, the output of which is through a duct 1468 and an or-gate 1469, acting as a check valve, to a line 1471 joining the manifold 1463.

Port Z1 has a line 1472 going to the air line 403 and internally is connected by a duct 1473 to a not-gate 1474, the output of which is through a line 1476 to the and-gate 1467. The line 1221 (Sheet 9) from the valve 1219 has a branch line 1477 going to port Z6, from which one branch 1478 goes to the a port of the not-gate 1474 and another branch 1479 goes to an and-gate 1481, from which the output is through an or-gate 1482, acting as a check valve, and through a connector 1483 to the manifold 1463 and so to port Z2.

With this arrangement, under normal operation with valve 1239 blocked, port Z7 is pressurized through line 1456 and its supply line 1233 coming from port U2. It is noted that port U2 is pressurized with A3 air within board U by a line 1486 from the U3 port supplied with A3 air from line 1171 and leading through an orifice unit 1487 and a line 1488 to a connector 1489 at one end joined to the duct 1232 arranged between the port U2 and the and-gate 1231. A3 air flows from port U3 through the orifice unit 1487, the line 1488 and the connector 1489, into the line 1232 and so out of the U2 port into the line 1233. The other end of the connector 1489 goes to the a port of a not-gate 1491. The input to the not-gate 1491 is of A3 air from the duct 1486 through a line 1492 having a branch 1493 to an and-gate 1494, the other input to which is from the line 1492 through a timer 1496 and a duct 1497. The and-gate 1494 is joined to the b port of the not-gate 1491, the c port of which is joined by a duct 1498 to the or-gate 1423.

Pressurization of the A3 air system thus enables the and-gate 1231, by means of the orifice unit 1487 and the connections 1488, 1489 and 1232, to pass signals from port U4 to port U1. A3 air is transmitted from the port U3 through the timer 1496 and the and-gate 1494 to the not-gate 1491, which is inhibited by the A3 air pressure downstream of the orifice 1487 through the lines 1488 and 1489, so no signals are available from this source at ports U6 or U7. But when the valve 1239 (Sheet 1) is shifted by excessive differential pressure, and the line 1233 is vented and port U2 is consequently vented, then not only is and-gate 1231 disabled, as described, but the inhibition is removed from not-gate 1491 and A3 air pressure from and-gate 1494 travels through the not-gate 1491, the or-gate 1423 and to port U7, and through the or-gate 1377 to port U6. Thus both ports U6 and U7 are pressurized. Line 1378 from port U6 then pressurizes port W4 and produces downshifts in the programmer, as previously described.

When line 1233 is vented and vents port U2, it also vents port Z7 through line 1456. When this port is normally pressurized, the not-gate 1459 is inhibited and passes no signals, but when port Z7 is vented the inhibition is removed and there is a clear path from port Z8 through line 1458, the not-gate 1459, the or-gate 1462, the manifold 1463 and the line 1483 to port Z2. The shut-down device 388 (Sheet 13), being connected through line 1457 to port Z8, is thus joined to port Z2.

A line 1501 runs from port Z2 to a port AA2 of a "Downshift To Position 3" board AA (FIG. 38, Sheet 6). Within board AA the port AA2 is connected by a line 1502 to an and-gate 1503, and the port AA7, joined by a line 1504 to port U7, is connected by a line 1506 to one inlet of an and-gate 1507, the other inlet to which is joined by a manifold 1508 to port AA8 at the end of the line 762 going to valve 672-12 (Sheet 12). The output of and-gate 1507 is carried by a line 1509 to an or-gate 1511 connected by a line 1512 to the and-gate 1503, at its outlet connected to vent.

The port Z2 thus connects the shut-down device 388 to the and-gate 1503 in board AA, but as long as the signal at port U6 continues to activate port W4 to produce programmer downshifts and pocket openings, the and-gate 1503 does not open line 1502 to vent. However, as soon as the programmer 660 has downshifted to Position 4 and has made cam 12 active, then valve 672-12 is shifted, line 762 is pressurized and port AA8 is also pressurized, so the inlet through line 1508 to and-gate 1507 is effective. The other inlet to and-gate 1507 is effective through line 1504 from port U7, pressurized as previously described.

The and-gate 1507, being thus enabled, pressurizes line 1509 and through or-gate 1511 activates the other input to and-gate 1503, which immediately opens to vent and so through the described circuit vents the shut-down device 388. When the device 388 is vented, it shifts to open the lines 389, 399, 403, 404 and 417 to atmoshpere, thus permitting valve 414 to spring-shift to vent position, and so permitting valve 419 to shift to vent. This relieves line 422, the check 423 and line 426, as well as line 448 and line 452. This last, being vented, permits closure of the fuel gas block and vent valve (not shown) controlling the gas supply to the engine, so that no more fuel gas is supplied and the engine and compressor slow to a stop.

In a somewhat related fashion, there is comparable response if at any time the BMEP of the engine is excessive and so potentially damaging. High BMEP is responded to by shifting of the relay 1209 (Sheet 9), which correspondingly shifts the diaphragm 1216, as previously described, to shift valve 1219 and so pressurize the line 1221 and port U5. This sends a signal in board U to inhibit the not-gate 1228 and prevent an upshift which would result from a signal from port U1, and also sends a signal through line 1422 and the or-gate 1423 to port U6, thus activating board W at port W4 to produce downshifting of the programmer.

Further, the signal from the or-gate 1423 pressurizes the port U7 and transmits a signal to port AA7 and to the and-gate 1507. However, the signal does not pass that point until the programmer is in Position 4 and cam 12 is available to pressurize line 762 and port AA8, upon which the signal is apparent at and-gate 1503. Now, when line 1221 pressurized port U5, the line 1477 joined to line 1221 also pressurized port Z6 and the connected and-gate 1481. The other input the the and-gate 1481 is joined by a duct 1516 to port Z5, from which a line 1517 extends to the shut-down device 387D concerned with high BMEP. There being pressure in board Z at both ports of the and-gate 1481, a signal is produced at port Z2, and so at port AA2 and through the line 1502 on the and-gate 1503. This, already being pressurized, immediately opens to vent, so venting line 1502 and port AA2, line 1501, port Z2, the or-gate 1482, the and-gate 1481 and port Z5. This in turn vents the shut-down device 387D, the line 389 and the same connections as just described in connection with the venting of the shut-down device 388, and ultimately closes the fuel gas block and vent valve and stops and engine and compressor.

In addition to excessive compressor discharge pressure, excessive differential pressure across the compressor, and excessive BMEP of the engine, there are other operating factors that are taken into account. An important one is excessive vibration of any of various of the components of the installation.

For example, various parts of the mechanism are provided with vibration responsive devices connected to corresponding ones of the shut-down devices 401-402, so that when vibration of the part is excessive or long-continued, the vibration responsive device trips the corresponding shut-down device and so shuts down the engine and compressor, thus avoiding difficulty. sometimes, however, in the normal operation of the installation, there may be excessive vibration of some parts for a short time, and this is not considered detrimental. Consequently, some of the vibration responsive devices are arranged to be cut out or made ineffective for a short time upon the occurrence of normal, transitory events causing substantial vibration.

For example, upshifting and downshifting of the programmer 660, by changing the operating ocnditions, may produce a transitory vibration until the plant settles down to the new condition. This is not considered harmful but the attendant vibration may be enough to operate a vibration responsive device and cause shut-down when no shut-down is really warranted. For this reason, there is provided a "Lock-out" board BB (FIG. 38, Sheet 10). This board at port BB3 is supplied with operating air from the line 421 through a branch 1518 and has an interior air line 1519 extending to an and-gate 1521 having an outlet going to port BB4. The line 1519 has a branch 1522 having a connection 1523 to an and-gate 1524 and itself ends at an and-gate 1526. Another branch 1527 from the line 1519 goes to a memory unit 1528. To port BB8 a branch 1529 extends from the line 1306 leading from port V7 of the "upshift-speed interlock" board V, and a similar branch 1531 at port BB6 is joined to the line 739 emerging from port J6 of the "downshift-speed interlock" board J. To port BB5 is connected a line 1532 going to a spring-pressed valve 1533 (Sheet 4) manually operated by the attendant and in one position connected to vent and in its other position supplying air from the line 342 to the line 1532.

Within the board BB the ports BB5 and BB6 are joined by ducts 1534 and 1536 to an or-gate 1537 connected to an or-gate 1538 also connected by a duct 1539 to port BB8. Thus, when the manual button of valve 1533 is depressed by the attendant and so puts a signal in line 1532 at port BB5, or when an upshift signal is put out by board V through line 1529 to port BB8, or when a downshift signal is put out by board J in line 1531 to port BB6, the signal is transmitted through the or-gates 1537 and 1538 or through the or-gate 1538 alone and emerges therefrom in a line 1541 to the second input port of the and-gate 1524, so that a corresponding signal therefrom travels through a conductor 1542 and a differentiator 1543 to a set-rest unit 1544, the output from which goes to the memory unit 1528. Being so enabled, the memory unit 1528 sends out a signal.

One part of the signal from the memory unit 1528 travels through the already partly energized and-gate 1521 and sends a signal from port BB4. The other portion of the signal from the memory unit 1528 goes through a line 1546 to a timer 1547 connected by a duct 1548 to the other input of the and-gate 1526, there being an accumulator 1549 in the line 1548. The timed signal in the line 1548 after a period affects the already partly energized and-gate 1526 to send a signal through a line 1551 to the set-reset unit 1544, interrrupting its output and stopping the signal from port BB4. While it persists, the timed signal from port BB4 is effective through a line 1552 to devices (not shown) effective to disable the vibration responsive devices, by only as long as that signal is coming from the port BB4. Thus, during and after an upshift or a downshift, the vibration responsive devices are automatically kept out of operation long enough to permit the mechanism to resume steady state operation. Also, the attendant can at any time produce a similary lock-out or a series of them by one or more pushes on the button for the valve 1533.

When the engine and compressor have finished their duty and are to be shut down, this is normally accomplished automatically by a signal from the attendant. He gives the signal by depressing a button shifting the normal stop valve 647 (Sheet 2) and so connects the A1 air line 644 through a branch 1556 to a line 1557 going to an or-gate 1558. A pressure line 1559 from a remote point also connects to the or-gate 1558, so a signal from the remote point can also initiate a normal stop. The or-gate 1558 is joined by a line 1561 to board O (Sheet 5) at port O4 and is also joined through a branch 1562 to board H (Sheet 5) at port H3. From port O4 the stop signal goes through a duct 1563 and through an or-gate 1564 to a duct 1566 connected to the or-gate 1011, from which the signal travels through the line 1012 and the or-gate 929 to the line 931 to reset the set-reset unit 911 for subsequent operation.

From port H3 the signal travels through a line 1567 and through an or-gate 1568 and a duct 1569 to port H4, from which a line 1570 goes to port Y6 (Sheet 6). In board Y, the "latched stop" board, the signal at port Y6 is effective through duct 1446 on the and-gate 1444 already partly energized by A1 air from port Y1, so that the board Y network is effective to produce the port Y6 signal at port Y2.

A similar result obtains whether the normal stop or the emergency stop signal is used. In an emergency stop, the button valve 454 (Sheet 13), as previously described, vents the line 426 and the connected lines 841, thus venting port H2 and through the duct 1571 removing the inhibition from a not-gate 1572, so that A1 air from connector 684 supplied through a duct 1575 at port H1 can go through a duct 1573 and through the not-gate 1572 and the or-gate 1568 as well as the duct 1569 to port H4, from which it travels through line 1570 to port Y6. A signal is thus produced at port Y2, as is the case during normal stopping.

Form port Y2 signals go the various palces. The line 1432 has a branch 1574 (Sheet 5) going to port M3 of board M (Sheet 10), wherein a duct 1576 inhibits the not-gate 781 and precludes an up-pulse. The line 1574 has a branch 1579 (Sheet 9) going to the not-gate 1358 is board X to stop signals from board V and also has another branch 1577 (Sheet 6) going to port A2 of board A (Sheet 13), wherein a duct 1578 carries the pressure through the or-gate 472 and the timer 473 and the line 476 to inhibt the not-gate 391, so that the signal at port A4 is stopped and pressure cell 394 is no longer pressurized, permitting valve 390 to shift back to the position illustrated in Sheet 13. Also, a signal from port Y2 goes through a line 1581 (Sheet 6) joined to the line 1432 and going to port AA6. Since cam 12 is in position and port AA8 is energized, the manifold 1508 also pressurizes part of an and-gate 1582, so that the signal at port AA6 travels through a duct 1583 to that and-gate and therefrom through a duct 1584 to an and-gate 1586. The other input to this and-gate 1586 is connected by a duct 1587 to port AA5, from which a line 1588 joins the line 1086 (SHeet 11) from valve 672-3. Since in Position 4, which the programmer occupies, cam 3 is active and has displaced valve 672-3, the lines 1086 and 1588 and so port AA5 are all energized. This affords an output from the and-gate 1586 through a duct 1589 to a timer 1591 and so into a line 1592 leading to the or-gate 1511 and the and-gate 1503, so that line 1502 remains vented.

The line 1592 is connected through a branch 1593 to port AA1, connected itself by a pipe 1594 to an accumulator 1596. The line 1592 also goes to an and-gate 1597, the other side of which is fed through a line 1598 from port AA4 joined by a line 1599 branching from line 879 coming from port Q7. This is a board Q, the "run-gas and dead engine" board, so that when the engine has stopped rotating and is dead, as previousl described, a signal from port Q7 travels through line 1599 and appears as port AA4. There is thus furnished a signal upon the and-gate 1597, and after a slight time delay due to the timer 1591, the and-gate 1597 is fully energized and pressurizes port AA3. The time delay permits slight cooling of the engine.

The signal from port AA3 is carried by a line 1601 to port CC5 of a "Downshift To Position 2 And 1" board CC (FIG. 40, Sheet 6). Within board CC the pressure at port CC5 is carried through a duct 1602 to an or-gate 1603 and from the outlet thereof through a line 1604 to an or-gate 1606 having a duct 1607 going to port CC2. From this port CC2 a line 1608 goes to port K8 (Sheet 10) of the down-pulse board K. In board K port K8 is joined by a duct 1609 to the or-gate 741 and, as previously described, the pressure therein produces a pulse at port K5 and in the line 760 to actuate the piston 668 to shift the programmer 660 from Position 4 to Position 3, in which cam 3 is no longer effective but cams 12, 2 and 1 remain effective.

Until the programmer moved back to Position 3, the various line valves retained the positions they were left in at the conclusion of the automatic start operation. That is, in position 3 during the stopping operation the blow-down valve 319 is closed, the bypass valve 312 is closed, the suction valve 306 is opened, and the discharge valve 308 is opened.

When the programmer resumes Position 3 and cam 3 is no longer effective, the valve 672-3 shifts to vent position, thus venting lines 1091, 1084 and 1588. Line 1091 vents port T7 and through board T also vents port T6 and line 1122. This vents port C4 and within the board C vents lines 1123 and 1124, thus removing the inhibition from the not-gate 1126 and allowing A2 air from port C3 to flow through lines 1127 and 1128 and through the or-gate 526 and the line 524 to pressurize port C8. This supplies pressure to line 523, which urges the actuator 307 to move the suction valve 306 to closed position.

The opening line 522 connected to port C6 is vented through line 521, the or-gate 519, the line 1123, and a line 1611 to a vented and-gate 1612, the other side of which is pressurized through a line 1613 from the pressurized closing line 524.

When the suction valve has moved into closed position, verification is had since the valve core 873 correspondingly moves to closed position, in which line 874 supplies pressure air to line 903 and so to port CC7. Within board CC the port CC7 is joined by a duct 1614 to an and-gate 1616, the other inlet of which is connected by a duct 1617 to port CC8. This is joined by a line 1618 to the line 697 supplied with air from valve 672-2 since cam 2 is active. From the and-gate 1616 a duct 1619 joins to one input of an and-gate 1621, the other input to which is connected by a line 1622 to port CC6. This port is joined by a line 1623 to the line 1581 connected by the line 1432 to port Y2. Thus, when the suction valve is verified to be closed, pressurizing port CC7, and when cam 2 is effective, pressurizing port CC8, and when the "latched stop" board Y pressurizes port CC6, then the and-gate 1621 sends a signal through a line 1624 to the or-gate 1603 and so pressurizes port CC2 and through line 1608 pressurizes port K8. Board K correspondingly sends a pulse from port K7, again energizing cylinder 668 of the programmer and producing a downshift from Position 3 to Position 2. In Position 2, cam 2 has become inactive and only cams 1 and 12 are effective.

When cam 2 permits valve 672-2 to open and vent line 697, lines 1054, 1056 and 1618 are vented also. Line 1056 to port D4 (Sheet 7) through line 1030 and its extension vents one input to the and-gate 1060, itself connected to vent, and through line 1035 removes the inhibition on not-gate 1040, thus permitting A1 air from port D3 to flow through a line 1050, the not-gate 1040, the line 1055 and the or-gate 552, and into the line 553 to supply a signal at port D8. This signal also enables the and-gate 1060 to vent to atmosphere and so vents port D6 through the or-gate 536. From port D8 air is supplied through line 554 to the closing end of the actuator 309 and so closes the discharge valve 308. As the valve 308 closes, it also moves the indicator valve 857 and from the line 828 pressurizes the line 854 going to port P5, thus enabling the and-gate 852 as heretofore described, while a branch 1620 is also pressurized and goes to port F2. Also pressurized is a line 1625 diverging from the line 1620 and going to port CC3. At port F2 the pressure from line 1620 is transmitted through a line 1626 to an and-gate 1627, already pressurized with A2 air through a connection 1628 from port F3. This port is supplied through a pipe 1629 joined to the A2 line 1078. When so pressurized, the and-gate 1627 releases a signal through a duct 1630 to the or-gate 604, from which the signal travels through duct 606 to port F7. Pressure in duct 1630 on a vented and-gate 1631 enables that gate through a line 1635 to open line 597 to vent, and through or-gate 598 also vents line 599 and vents line 601 connected to port F4. Pressure at port F7 is sent through the line 607 to the opening end of the actuator 313 and so opens the bypass valve 312. The corresponding indicator valve 863 is likwise moved and supplies air from the line 866 to line 862 going to port P4, thus enabling the and-gate 859, as previously described.

At board CC the port CC3 is pressurized, as just noted, port CC6 is pressurized from the line 1623 connected to port Y2, and port CC4 is pressurized through a line 1632 going to line 698, which is active since cam 1 still holds valve 672-1 displaced. Thus an and-gate 1633 is pressurized through a duct 1634 joined to the line 1622 going to port CC6 and through a duct 1636 going to port CC3. Through a line 1637 the enabled and-gate 1633 activates one input of an and-gate 1638, the other input to which is activated through a duct 1639 going to port CC4. The and-gate 1638 thus provides an output through a line 1641 to a not-gate 1642. The not-gate 1642 can be inhibited through a line 1643 joined to line 1617 going to port CC8, but there is no pressure at port CC8 at this time since the line 1618 connected thereto is vented by the inactivity of cam 2. Consequently, the signal in line 1641 goes through the not-gate 1642 and emerges through a duct 1644 into and through the or-gate 1606 to pressurize port CC2 and through the line 1608 to pressurize port K8. As before, when so energized, the board K is effective to provide a down-pulse to the cylinder 668 and so shifts the programmer into Position 1, in which cam 1 becomes ineffective and only cam 12 remains effective.

Just before the shift-down to position 1, the gas line valve situation is that the blow-down valve 319 remains closed, the bypass valve 312 has been opened, the suction valve 306 is closed, and the discharge valve 308 is closed. Now, in position 1 since cam 1 is no longer effective and the valve 672-1 is in vent position, the various lines connected thereto are also vented. That is, line 816 going to port E5 is vented and so vents the duct 817 going to the not-gate 818 supplied through the duct 819 from port E4. A1 air from the line 680 and the trunk line 683 is present at port E4. When port E5 is vented, the not-gate 818 is no longer inhibited and so A1 air flows from duct 819 through the not-gate 818 and into a duct 1646 itself connected to and enabling a vented and-gate 1647. Since the branch 821 from the not-gate 818 goes to the or-gate 561, a signal is thus impressed at port E2 and to the line 563 so that the actuator 321 opens the blow-down valve 319. This movement is verified by shifting the indicator valve 826 to vent the line 831 and remove pressure from port N4. This inactivates the cascade of and-gates therein and stops any output from port N7.

Since in Position 1 cam 1 is no longer effective and line 1434 is relieved of pressure and is vented, so also is port Y3 vented. This removes the inhibition from the not-gate 1439 so A1 air can flow through lines 1436 and 1438, the not-gate 1439 and line 1441 to actuate the set-rest unit 1442 and so "unlatch" the "latched stop" board Y, thus restoring the entire plant to its stop condition and ready for future start-up.

In Position 1, the line valves are left with the blow-down valve 319 opened, the bypass valve 312 opened, the suction valve 306 closed, and the discharge valve 308 closed, which is the appropriate position for future beginning of automatic load operation.

According to the disclosure, there is provided an engine-driven compressor with associated operating and control devices arranged to afford various degrees of local or remote control, from nearly all manual operation to nearly all automatic operation, not only of the engine-compressor combination but also of line valves at the compressor inlet and discharge as well as valves in the compressor itself and of many of the engine auxiliaries. Operational or positional signals of a continuously variable or analog nature, even though slight, are transposed to digital or pulse signals of a definite or forceful nature so that the resulting operation is both sensitive and sure. The engine and compressor performances are automatically regulated to the requirements in an optimum fashion. The arrangement, except for fully housed engine ignition, is entirely non-electrical, so that installation can be safely made in combustion-hazardous surroundings, yet the lag and elasticity often detrimental in pneumatic systems are obviated. The extent of the system is sufficient to afford a self-contained plant able to contend with all of the usual operating variations and to control itself automatically for indefinite periods subject only to normal maintainance and to shut itself down properly should there be operating difficulties. The plant control, by reason of the various readily changeable pneumatic control boards, can be simply serviced or can be altered from time to time to follow different regimens. Servicing is safe and simple and costs are reasonable. In protracted operation, the arrangement has proved to be advantageous and a distinct advance.