Title:
Boiler feed pump apparatus
United States Patent 2007138


Abstract:
This invention relates to boiler feed pump apparatus and has for its objects improved apparatus for automatically returning water of condensation from steam lines back into the boiler as well as supplying additional water to make up for any losses. Other objects of the invention are an arrangement...



Inventors:
Becker, Jesse O.
Application Number:
US73858534A
Publication Date:
07/02/1935
Filing Date:
08/06/1934
Assignee:
BECKER PUMP COMPANY
Primary Class:
Other Classes:
415/212.1, 417/78, 417/185
International Classes:
F22D11/02
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Description:

This invention relates to boiler feed pump apparatus and has for its objects improved apparatus for automatically returning water of condensation from steam lines back into the boiler as well as supplying additional water to make up for any losses. Other objects of the invention are an arrangement providing for the use of a rotary or centrifugal pump whereby a continuous action is had as against the intermittently operating devices of the prior art, also such an apparatus which will be reliable in operation.

Other features and advantages of the invention will appear in the following description and the accompanying drawing.

5 In the drawing Fig. 1 is an elevation of the general arrangement of elements for achieving the objects sought.

Pig. 2 is an enlarged vertical section of the automatic valve used on the exhaust steam line 0 leading to the apparatus to pass condensed water but not steam.

Fig. 3 is an enlarged vertical section of the special balancing valve through which the water is forced into the boiler.

U Fig. 4 is an enlarged vertical section of the special centrifugal pump used to inject the water into the boiler.

Fig. 5 is a cross section of Fig. 4 as seen from the line 5-5 thereof.

) Fig. 6 is a substantially full-size section of one of the pump runner arms for an ordinary laundry installation.

Fig. 7 is an end view of Fig. 6.

Fig. 8 is a cross section of Fig. 7 taken along 5 the line 8-8.

Generally described my invention comprises a closed circulatory water system operated by a high pressure continuously revolving rotary pump circulating the water through piping and through a tank kept full of water, and incorporating in the pipe system an aspirator to draw into it any water of condensation from the boiler steam lines with which it is used and force this extra water through a pipe back into the boiler against the pressure thereof. Also incorporated in the piping system is a special valve to avoid drawing steam from the condensed steam line at times when there may be no water available, while preferably on the pipe line through which the condensed water is pumped back to the boiler is a check or special balancing valve which will i only open at a pressure above the working boiler pressure and when there is an excess pressure I in the water circulating line so that the apparatus t can not pump into a cold boiler nor can the ( boiler pressure enter the water circulatory sys- s tem which normally runs at a lower pressure 9 and only at increased pressure when more water t enters it, for reinjection into the boiler. Also t forming part of the invention is a cold or service water connection to the circulatory system which is normally closed but is opened by any suitable boiler water level, control so as to deliver extra water to the system if the boiler water level falls below a predetermined minimum. By the systern outlined, and which is fully automatic, the apparatus is greatly simplified over that formerly required. Reciprocating pumps working in very hot water with the danger of becoming steambound, intermittently operating injectors, water level float valves in the hot well, etc., are all avoided, and the operation of the apparatus is rendered certain and reliable.

In the drawing I is the driving electric motor direct connected to a special centrifugal pump 2 bolted to the side of the motor and receiving water through a pipe 3 extending from the lower part of a closed water tank 4, here shown mounted on the motor (though it may be mounted in any convenient manner, preferably elevated above the pump), and the discharge pipe 5 of the pump injecting the water back into the tank, preferably near the upper end for circulating through the closed tank and out through pipe 3 as described as denoted by the dotted line in the tank. Pipe 5 extends into the tank as at 5' and is preferably apertured along its sides as at 6 to facilitate upward escape of steam so as to avoid its recirculation through the pump.

On the closed head of the tank is an adjustable safety valve 63, and an automatic or manually operated air blow-off valve 7, the latter permitting escape of any cool air in the tank when starting up, yet closing when the water fills the tank or on contact with hot steam, thus insuring the tank, pump and circulating pipes 3 and 5 to be full of water though not precluding some steam on top.

Within the pump is an aspirator or injector 13 (see Fig. 5) arranged at the immediate discharge from the pump casing and provided with a nozzle 14 and auxiliary water inlet 15 leading from the lower end 16 of any steam pipe system on which the apparatus is installed so as to draw into the pump circulating system any condensed water which may be in the steam piping and force it along pipe 5 to the tank 4, but since the tank is full the excess water is forced out of the top of the tank through a pipe 17 past a swing check valve 18 and/or a special valve 19 directly back nto the boiler 29.

Make-up water to compensate for losses is sup?lied to the system from a pipe 10 leading from my desired source of water under pressure in exdess of the boiler pressure such as high pressure ervice or pressure tank, not shown, to a fitting I on pipe 17 and the flow from which pipe is conrolled by a valve 1 operated by any desired elecric or other remote control by the level of water n the boiler, not shown, the arrangement being such as to normally hold the valve closed but open it when the boiler water level falls to a predetermined minimum and again close it upon rise of the level. A swing check valve 12 is also incorporated on pipe 10 as a safety precaution against any chance of the pump forcing water back into the main. Also a conventional pressure gage is provided at 61 and a service cock at 62.

In some steam systems wherein this apparatus is useful, as soon as the condensed water is drawn out of the steam piping, a considerable steam pressure lies behind the condensed water and would follow it into the pump aspirator, and to avoid this I provide a special valve 20 on the condensed steam line 16. This valve may take the form shown in detail in Fig. 2 wherein it will be seen to be a conical valve 21 provided with a stem 22 passing slidably through a stuffing box 23 and - slidably through the valve housing frame with its upper end secured to a flexible diaphragm forming one wall of a closed chamber 24 connected by a pipe 25 to condensed steam pipe 16 at a point between valve 20 and pump 2, and which pipe is fitted with a needle valve 26. A spring 27 around the valve stem normally seats the valve, and the outer side of the diaphragm is vented at 28 to avoid any resistance to closing. The action of this valve Is to remain open due to partial vacuum created in chamber 24 by suction in pipe 16 leading to the aspirator of the pump while water is being drawn through to the pump, but the moment the water is all withdrawn and steam arrives, this expands through pipe 25 and into chamber 24 thus breaking the vacuum and closing it at once, and thereby substantially preventing any steam entering the pump. Needle valve 26 will control It against too abrupt action.

A safety provision on the feed water return pipe 11 leading to the boiler, desirable in high pressure systems, is a special valve 19 as shown in detail in Pig. 3. This device is provided with a conical valve 30 having a stem 31 passing slidably through a stuffing box 32 and provided with a spring 33 for normally seating the valve, while the upper end of the stem is pivotally connected at 34 with a rocker beam 35, the ends of which are pivoted at 36, 37 with rods 38, 39 respectively of pistons 40, 41, operating in small cylinders 42, 43 respectively connected by a pipe 44, 45 to opposite ends of the valve body or at opposite sides of its valve 30.

The pivotal connection 34 is by means of a pivot pin fixed in the rocker beam and with the pin engaging a vertical slot 46 in a yoke -47 secured to the upper end of the stem. The pivotal connections to the piston rods 38, 39 are made by yoking the ends of the beam and slotting them as at 48 for the pins fixed in the rods. The cylinders 42 and 43 are shouldered within to permit limited rise to their pistons and which is so proportioned in connection with slot 46 as to prevent the valve 30 from opening unless both pistons are raised to their limit. The pressure required to raise the pistons may be independently fixed by means of nuts 49, 50, threaded into the reduced upper ends of the cylinders and bearing against heavy springs 51, 51', reacting against the upper ends of the pistons respectively. The device may, therefore, be set to open with a minimum pressure on the boiler side, and a different minimum pressure on the pump side. However, in some installations a by-pass valve 52 may be turned to open a channel 53 leading from opposite ends of the valve body and check valve 18 may be relied upon to prevent the boiler pressure working back into the system, but with device 19 the pressure required to force the excess water back into the boiler may be set at a point greatly in excess of the boiler pressure, and not merely superior as would be the case where reliance were placed entirely on check valve 18. As a system of this kind requires the pump to maintain a pressure of perhaps a hundred and fifty pounds or more while running in very hot water it is evident that an ordinary centrifugal pump will not work and that most other pumps would speedily give out. The pump here shown, however, when of about ten inches internal diameter and revolving at a speed about 3400 to 3600 R. P. M.'s will deliver 18 to 20 gallons of water a minute at a pressure of about 190 pounds per square inch with a five horse-power motor. The pump consists of a hollow rotor 54, preferably of smooth non-corrodible metal, provided with four tapering tubular impellers 55 reduced at their ends to the dimensions shown substantially full size in Figures 6, 7 and 8, and of a sectional form shown in Fig. 7 arranged to travel with the rounding nose leading and the tapering edge trailing as denoted by the arrow. The actual interior of the impeller arms adjacent the hub is about 1A" x 7/16" and at the extreme end A" x about 1/2" or less tapering as shown in Fig. 7 and the ends of the runners about a half inch from the wall of the peripheral water channel 56. The inner area of the arms from base to outlet may be from about 1 to 20 or 1 to 30 difference in cross sectional area.

The impeller freely clears the sides of the casing as shown in Fig. 4 and is open centrally at 57 for entrance of water from pipe 3 of the circu- 36 latory system, and is provided with a hub 58 secured to the end of the motor shaft which extends through a stuffing box 59. The water is expelled tangentially from the casing through port 60 through the aspirator 13-14 to draw in the condensation water from the steam lines.

While the special centrifugal pump above described will easily maintain a pressure of over 200 pounds if desired, in systems involving a difference of over about 1 to 6 in pressure between the boiler pressure and the exhaust steam lines to be pumped out by the pump there is a tendency for the pump pressure to back up through aspirator inlet 15 as such aspirators, or venturi's as generally called, do not operate well at differences greater than these, and while in most industrial installations where steam is used as the equipment heating means, as in laundries, all traps are removed from the exhaust line and the difference in pressure is easily handled by one -pump, but in installations operating under greater than 1 to 6 ratios I use the same pump but made in two or more stages as may be necessary, the output of one delivered to the input of the other in the conventional way well known in the art and requiring no further exemplification in the drawing.

With the apparatus as above described any steam heating line may be automatically kept free of condensed water, the pump continuously circulating through the tank 4 will pick up any extra water from the steam system, and since it has nowhere to go as the circulating pipes 3, 5, and tank 4 are full, must be diverted through the pipe 17 and as the pressure at once builds up above the boiler pressure this extra water must be forced back into the boiler. The presence of steam in the return water will not materially affect the operation of the pump as it handles the steam as well and condenses most of it back to water, and any accumulating in the upper en of the tank will be the first to be re-injected int the boiler.

Since the path through the circulatory syster is always the one of least resistance it follows tha the system will always be kept full of water though while the pump is merely circulating it i not absorbing much power.

The system is, of course, applicable to an: steam pipe heating system as applied in heatinj for any industrial purpose.

Having thus described my invention it will bc evident that minor changes may be made with out departing from the spirit of the inventioz and as may come within the scope of my appende( claims.

In my claims the term "kept full of water" ap, plied to the tank or water circulatory system it to include the chance existence of some stean which may occasionally accumulate for a time ir the upper part of the tank upon valve 20 noi operating perfectly or in cases where for some reason it is not used.

I claim: 1, Automatic boiler feed apparatus comprising E water circulatory system including a closed pressure tank through which the water must flow, a pump in said system arranged to keep the water in continuous circulation, an aspirator in the discharge line from the pump adapted to draw condensation water into the system from a steam pipe line, a boiler feed pipe line from the pressure side of the circulatory system leading into the boiler, and a valve on the boiler feed line adapted to open upon increase of pressure above that of the boiler built up in said system upon entry therein of such condensation water.

2. In a structure as specified in claim 1, an air escape valve on said tank adapted to close when the tank is free of air.

3. In a structure as specified in claim 1, said pump being a centrifugal pump and the aspirator arranged within the pump casing adjacent the water discharge port.

4. In a structure as specified in claim 1, a valve on the steam pipe line adapted to pass condensation water and to close in the presence of steam.

5. In a structure as specified in claim 1, a valve on the steam pipe line adapted to pass condensation water and to close in the presence of steam, and means for controlling the freedom of response of said valve.

6. In a structure as specified in claim 1, said valve on the boiler feed line provided with pressure responsive means whereby it will open only upon predetermined pressure respectively in the line at both sides of said valve.

7. In a structure as specified in claim 1, said valve on the boiler feed line provided with pressure responsive means whereby it will open only upon predetermined pressures respectively in the line at both sides of said valve, and a valved by-pass around said valve.

8. In a structure as specified in claim 1, said a5 valve on the boiler feed line provided with pressure responsive means whereby it will open only upon predetermined pressures respectively in the line at both sides of said valve, and means for independently adjusting the pressure responsive means.

9. In a structure as specified in claim 1, a water service pipe delivering the water to said system under pressure in excess of the boiler pressure, and .d a controlling valve on said water service pipe o for admitting water to said system for making up losses and for feeding to the boiler.

n 10. In a structure as specified in claim 1, a ,t water service pipe delivering water to said system r, under pressure in excess of the boiler pressure, and s a controlling valve on said water service pipe opened and closed respectively by drop and rise y of water level in the boiler for automatically adg mitting water to said system for feeding to the boiler and making up loss of water in the boiler e and the circulatory system.

11. In a structure as specified in claim 1, said i valve on the boiler feed line provided with presI sure responsive means whereby it will open only upon predetermined pressures respectively in the line at both sides of said valve comprising a seps arate cylinder open respectively to the pressure 1 at each end of the valve body, a plunger in each 1 cylinder, and means operatively connecting both t plungers to the valve stem in a manner whereby e both plungers must be forced outwardly by the pressure to open the valve.

12. In a structure as specified in claim 1, said pump comprising a centrifugal pump provided Swith hollow tubular impellers rotatable therein, said impellers each tapering to their outere extremities to less than one-tenth their area at their * inner ends respectively.

13; In a structure as specified in claim 1, said O3 pump comprising a centrifugal pump provided with hollow tubular impellers rotatable therein, said impellers each tapering to their outer extremities to less than one-twentieth their area at their inner ends respectively. 14. In a structure as specified in claim 1, said pump comprising a centrifugal pump provided with hollow tubular impellers rotatable therein, said impellers each tapering to their outer extremities to less than one-tenth their area at their inner ends respectively and of flattened shape set edgewise to the rotation.

15. Apparatus of the character described comprising a centrifugal pump, a discharge pipe from said pump leading into a closed tank, a suction pipe from said tank leading to the intake of the pump for maintaining a circulation of water through said tank, a branch pipe from the system arranged for feeding water to a boiler and provided with a check valve against return flow, and a pipe introducing excess water to the circulatory system for ejection through said branch pipe and out of said circulatory system.

16. Apparatus of the character described comprising a circulatory water system including a pump for maintaining the water in circulation, a pipe leading from the pressure side of said system to a boiler and check-valved against return flow, and means for introducing excess water to said system for ejection through said pipe out of said '69 circulatory system to said boiler.

17. Apparatus of the character described comprising a circulatory water system including a centrifugal pump for maintaining, the. water in circulation, an aspirator on the output duct of said pump, a pipe leading from the pressure side of said system to a boiler and check-valved against return flow, and means for introducing excess water to said system through said aspirator for ejection through said pipe out of said circulatory system to said boiler.

JESSE 0. BECKER.