Diaphragm valve for controlling supply of gas to water heater
United States Patent 3917162
Valve for controlling flow of gas to water heater comprises two chambers separated by a diaphragm. A first chamber has a gas inlet and a gas outlet leading to the burner of the heater. The outlet is controlled by the diaphragm position which is in turn dependent on the relative pressure in the chambers. A by-pass connects the two chambers, and the diaphragm position is therefore dependent on the exhaust from the second chamber, which is controlled in response to the flow of water to the heater and the temperature of the water.
US Patent References:
Automatic control valve
Eberspacher - September 1932 - 1878270
Gas switch
Hegwein et al. - July 1935 - 2009193
Condition responsive control apparatus
Matthews - August 1958 - 2848167
Continuous flow fluid heater control
Miller - January 1964 - 3118600
ARRANGEMENT IN A HOT-WATER CIRCULATION HEATING WITH DOMESTIC WATER HEATER
Meier - February 1969 - 3426971
Automatic control valve
Eberspacher - September 1932 - 1878270
Gas switch
Hegwein et al. - July 1935 - 2009193
Condition responsive control apparatus
Matthews - August 1958 - 2848167
Continuous flow fluid heater control
Miller - January 1964 - 3118600
ARRANGEMENT IN A HOT-WATER CIRCULATION HEATING WITH DOMESTIC WATER HEATER
Meier - February 1969 - 3426971
Inventors:
Trotter, Albin (Santiago, CE)
Trotter, Ursus (Santiago, CE)
Trotter, Ursus (Santiago, CE)
Application Number:
05/526211
Publication Date:
11/04/1975
Filing Date:
11/22/1974
View Patent Images:
Export Citation:
Primary Class:
Other Classes:
137/87.030
International Classes:
F23N1/08; F23N5/10; F23Q9/14; F24H9/20; F23N5/02; F23Q9/00; F22B35/00
Field of Search:
236/23,25R 137/87
Primary Examiner:
Wayner, William E.
Assistant Examiner:
Tapolcai Jr., William E.
Attorney, Agent or Firm:
Brisebois & Kruger
Claims:
What is claimed is
1. In a diaphragm valve for controlling the flow of gas to a water heater including a burner and equipped with a magnetic member responsive to variations in the flow of water to said heater, said valve comprising first and second chambers separated by a diaphragm, said first chamber being provided with a gas inlet and an outlet leading to said burner, and said diaphragm being movable between a first position closing said outlet and a second position in which said outlet is left open in dependence on the relative pressure in said chambers, the improvement which comprises
2. A valve as claimed in claim 1, in which said magnetically actuated valve comprises a magnetic piston movable inside a hollow body and actuated by the variations in the magnetic field between one end of said magnetic piston and the magnetic member responsive to the variations in the water flow, said piston being provided with a resilient disc attached to the end thereof remote from said one end and positioned to cooperate with a seat in said duct means to control the exhaust of gas from said second chamber.
3. A valve as claimed in claim 2, in which the resilient disc attached to said magnetic piston controls a connection between the second chamber of the diaphragm valve and a gas inlet to said burner, said connection being magnetically controlled in response to variations in the flow of water entering the water heater independently of variations in the temperature of the outlet water.
4. A valve as claimed in claim 1 in which said heat responsive valve means comprises a perforated pin in said duct means having in one end a gas outlet facing the conical end of a bellows responsive to the temperature of the water heated by said heater.
5. A valve as claimed in claim 4, in which said perforated pin is manually adjustable from outside the valve and said adjustment determines the amount of the maximum flow of exhaust gas and thereby determines the extent to which said diaphragm opens said outlet.
6. A valve as claimed in claim 5, in which said perforated pin is provided with at least one small diameter discharge orifice which permits a small exhaust flow sufficient to maintain a "minimum flame" at the burner even when the conical end of the bellows totally closes the outlet in the end of said perforated pin.
7. A valve as claimed in claim 1, which comprises an ignition retarding valve including a disc having at least one small orifice therein aligned with a larger orifice in said duct means, said disc being enclosed in a housing having at least one orifice leading to said second chamber, said disc being positioned to be lifted by gas flowing into said second chamber to permit rapid charging thereof, but depressed to partially obstruct said larger orifice when gas is being exhausted from said second chamber.
8. A valve as claimed in claim 1 comprising electromagnetic closure means connected to cut off the flow of gas to said burner whenever a pilot light is unlit, and an activator pin capable of opening said closure means only when a main valve controlling gas flow to said burner is in its closed position.
1. In a diaphragm valve for controlling the flow of gas to a water heater including a burner and equipped with a magnetic member responsive to variations in the flow of water to said heater, said valve comprising first and second chambers separated by a diaphragm, said first chamber being provided with a gas inlet and an outlet leading to said burner, and said diaphragm being movable between a first position closing said outlet and a second position in which said outlet is left open in dependence on the relative pressure in said chambers, the improvement which comprises
2. A valve as claimed in claim 1, in which said magnetically actuated valve comprises a magnetic piston movable inside a hollow body and actuated by the variations in the magnetic field between one end of said magnetic piston and the magnetic member responsive to the variations in the water flow, said piston being provided with a resilient disc attached to the end thereof remote from said one end and positioned to cooperate with a seat in said duct means to control the exhaust of gas from said second chamber.
3. A valve as claimed in claim 2, in which the resilient disc attached to said magnetic piston controls a connection between the second chamber of the diaphragm valve and a gas inlet to said burner, said connection being magnetically controlled in response to variations in the flow of water entering the water heater independently of variations in the temperature of the outlet water.
4. A valve as claimed in claim 1 in which said heat responsive valve means comprises a perforated pin in said duct means having in one end a gas outlet facing the conical end of a bellows responsive to the temperature of the water heated by said heater.
5. A valve as claimed in claim 4, in which said perforated pin is manually adjustable from outside the valve and said adjustment determines the amount of the maximum flow of exhaust gas and thereby determines the extent to which said diaphragm opens said outlet.
6. A valve as claimed in claim 5, in which said perforated pin is provided with at least one small diameter discharge orifice which permits a small exhaust flow sufficient to maintain a "minimum flame" at the burner even when the conical end of the bellows totally closes the outlet in the end of said perforated pin.
7. A valve as claimed in claim 1, which comprises an ignition retarding valve including a disc having at least one small orifice therein aligned with a larger orifice in said duct means, said disc being enclosed in a housing having at least one orifice leading to said second chamber, said disc being positioned to be lifted by gas flowing into said second chamber to permit rapid charging thereof, but depressed to partially obstruct said larger orifice when gas is being exhausted from said second chamber.
8. A valve as claimed in claim 1 comprising electromagnetic closure means connected to cut off the flow of gas to said burner whenever a pilot light is unlit, and an activator pin capable of opening said closure means only when a main valve controlling gas flow to said burner is in its closed position.
Description:
SUMMARY OF THE INVENTION
The object of the present invention is to improve the magnetic-mechanical valves or devices employed for the control of the gas flow in instantaneous water heaters, as disclosed in U.S. Pat. No. 3,806,026, dated Apr. 23, 1974.
The devices disclosed in said patent represented a substantial improvement and novelty in the field of the gas flow control devices for water heaters because by the use of a novel magnetic device comprising a hollow magnetic piston and a set of permanent magnets mounted on the arms of a tilting lever, the invention provided for both the progressive lighting of the water heater burner and the instantaneous cut-off of said burner in the event no water is flowing.
In addition to the above mentioned feature, a novel thermostatic device provided a constant "modulation"of the burner flame, at the user's option, as a function of the water flow, preventing the over-heating of the heat-exchanger coil, and eliminating all the problems usually encountered in conventional water heaters.
Practical use has shown that despite the fact that the system disclosed in said U.S. Pat. No. 3,806,026 is sufficiently efficient to serve all the above purposes, the additional modification and improvements according to the present invention provide a simpler system which operates more satisfactorily and costs less to manufacture.
Fundamentally, the improved device which is the object of the present invention comprises a novel assembly of magnetic elements controlling the opening or closing of a diaphragm type main gas valve, which can be regulated through its entire opening range by means of a novel thermostatic control system.
To additionally provide a high degree of safety, the improved valve according to the invention is provided with a failsafe system, using a thermocouple (which is not in itself the object of this invention) which in turn controls a magnetic coil that prevents the lighting of the main burner in the event the "pilot-flame"is not lighted.
The following is a description, as an illustrative example, of a preferred embodiment of the present invention, with reference to the accompanying drawing which is a side elevation of the system with the magnetic device and the improved diaphragm valve shown in section.
As illustrated in the FIGURE at the left side of the drawing there is a hollow metal body 1 connected at its two ends to the inlet and outlet ducts 2 and 3 through which the water to be heated in the heat-exchanger coil 4 of the instantaneous water heater circulates.
Inside the hollow body 1 are stop rings 5 and 6 limiting the axial movement of the hollow piston 7, which is formed by a permanent magnet.
As disclosed in U.S. Pat. No. 3,806,026, the magnetic hollow piston 7 moves upwardly or downwardly inside the body 1 in dependence on the flow of water through the ducts 2 and 3. When the flow increases, the magnetic piston 7 will move upwardly until it abuts against the stop ring 6, and, conversely, the piston 7 will move downwardly when the flow decreases until it is seated on the bottom ring 5 when the flow stops.
The broken lines show the piston 7 at its bottom position when there is no flow in duct 2, and the solid lines show said piston in its upper position when the water is flowing.
A second, short, hollow metal body 8 projects from the center part of the hollow metal body 1, at a right angle relative to the geometrical axis of the body 1. The body 8 has inlet and outlet nozzles 9 and 10 respectively for discharging the gas flow from the diaphragm valve.
Inside the hollow body 8 is a solid magnetic piston 11 having its North pole facing the North pole of the magnetic piston 7, across the wall of the body 1 when the piston 7 is at its bottom position.
The other end of the piston 11 (i.e., its South pole) is provided with an elastic disc 12 made of rubber, neoprene or the like, the position of which permits or prevents the flow of the gas through the nozzles 9 and 10. The nozzle 10 projects into the body 8 forming a seat 13 for the resilient disc 12 and providing a gas-tight seal when the magnetic piston 11 is remote from the magnetic hollow piston 7 due to the magnetic repulsion produced when the North poles of both magnets 7 and 11 are facing each other.
This assembly -- which is controlled by the fluctuations in the stream of water flowing through the instantaneous water heater, which fluctuations are produced by the user or being caused by variations in flow in the water mains, controls a diaphragm type gas valve 14, which in turn controls the gas feed to the burner 15.
The diaphragm valve 14 comprises an upper chamber 16 and a lower chamber 17, separated by a diaphragm 18 made of a resilient material, said diaphragm having in its center a closure disc 19 made of metallic or resilient material. The gas inlet 20 opens into the upper chamber 16 which has in one wall the seat 21 for the closure disc 19 of the diaphragm 18. Between the gas inlet 20 and the seat or nozzle 21 is a closure valve 22 biased closed by a spring but held open by a solenoid 23 activated by a thermoelectric device 24 responsive to the pilot flame 25 when that flame is lit. In the upper part of the valve body 14 is located the conical gas valve 26 defining a duct or orifice 27 leading to the pilot flame 25.
The stem and body of the conical valve 26 are axially perforated to accommodate a pin 28 ending in a knob 29. The pin 28 is biassed by the helical spring 30 away from the closure valve 22 which, when seated on seat 22a, interrupts the gas flow. To initially permit the flow of gas to the "pilot" 25 it is necessary to press the knob 29 inward, and this can be done only when the conical valve 26 is closed, because of the half 29a of said knob which must be introduced in a corresponding slot in the knob 29b of the conical valve 26. In the lower valve chamber 17 is a novel ignition retarding valve comprising a box 31 having orifices 32 in its upper part. Inside the box 31 is a small disc 33, made of metal or other material, having at least one small orifice 34 therein.
The lower chamber 17 and the upper chamber 16 of the diaphragm valve are connected by a duct 35 connected to a duct 36 which in turn connects the ignition retarding valve 31 with the perforated pin 37 of the temperature regulator 38 located in the lower part of the valve 14.
The temperature regulator 38a comprises a threaded portion 39 adapted to be rotated by the knob 38 to permit the forward or backward movement of the perforated pin 37 relative to the conical end 40 of the thermostat 41 which is connected to the capillary tube 42 connected to a bulb 43 suitably immersed in the heat-exchanger coil 4 of the instantaneous water heater in order to sense the water temperature.
The duct 36 in the lower body 17 of the diaphragm valve leads to a duct 44 which receives a regulating screw 45 to regulate the "minimum flame."
The duct 44 is connected to the outlet nozzle 46 which is also connected to the chamber 47 containing the conical end 40 of the thermostat and the end of the perforated body 37 of the temperature regulator.
The outlet nozzle 46 is connected to the nozzle 9 of the hollow body 8 through a duct 48 having a small diameter, and the outlet nozzle 10 of the body 8 is connected to the conical valve 26 through a tube 49 likewise having a small diameter.
In operation, the control valve assembly according to this invention operates as follows:
a. When the valve 22 is opened, by depressing the knob 29 to ignite the pilot, the combustible gas enters the diaphragm valve 14 through the gas inlet 20, thus filling the upper chamber 16, and flows through the duct 35 to duct 36 and thence through the "ignition retarding valve" 31 to fill the lower chamber 17.
b. When the flow of water to the water heater is interrupted, the hollow magnetic piston 7 is on its bottom position 5 and the repulsion between the North pole of the magnet 7 and the North pole of the magnetic piston 11 urges the closure disc 12 against its seat 13, preventing gas flow between the lower chamber 17 of the diaphragm valve 14 and the ducts 48, 49 to the burner 15.
c. When the seat 13 is covered by the closure disc 12 of the magnetic piston 11, the pressure in the lower chamber 17 and the upper chamber 16 is equalized and the spring forces the diaphragm 18 and the closure disc 19 to seat against the seat 21, interrupting gas flow to the burner 15 from the upper chamber 16.
d. When a predetermined stream of water flows through the hollow body 1, the hollow magnetic piston 7 moves from its bottom position 5 to its upper position 6, and the South pole of the magnetic piston 7 faces the North pole of the magnet 11 located in the hollow metal body 8, thus producing a magnetic attraction and withdraws the closure disc 12 (attached to the South pole of said magnet 11) from its seat 13 permitting communication between the gas nozzles 9 and 10 and permitting the exhaust of the gas accumulated in the lower chamber 17 of the diaphragm valve 14, which gas flows through the ducts 48 and 49 to the main heater of the burner 15, if and when the conical valve 26 is in its "open position."
e. On the other hand, due to this gas exhaustion a pressure reduction is produced in the lower chamber 17 relative to the pressure in the upper chamber 16, so that the diaphragm 18 moves downward to open the seat 21 and allow the flow of gas to the burner 15.
When the lower chamber 17 is connected to the burner 15 through the conical valve 26, a gas exhaust is produced and the disc 33 is seated against the seat at the end of the duct 36 and the gas accumulated in the lower chamber 17 is slowly released through the small diameter orifice 34 of the disc 33.
f. The slow release of the accumulated gas permits the diaphragm 18 to gradually uncover the opening of the duct 21, so that the ignition of the burner 15 is produced slowly as the lower chamber 17 of the diaphragm valve is emptied, thus preventing the sudden ignition of the burner. This is advantageous because there is no sooting of the burner and no detonation noise.
g. When the water flow through the duct 2 decreases for any reason, or if said flow is completely interrupted, the hollow magnetic piston 7 descends to its bottom position, and the magnetic attraction exerted on the magnetic piston 11 is replaced by a magnetic repulsion that reaches its maximum intensity when the magnetic piston 7 is at its lowermost position.
The movement of the magnetic piston 11, in dependence on the water flow variations controls the passage of the gas between the nozzles 9 and 10 thus controlling the passage of gas to the burner 15, because when the flow of gas from the lower chamber through the duct 48 is interrupted, the gas pressure will be equalized inside both chambers 16 and 17, forcing the rapid movement of the diaphragm to close the inlet 21 and interrupting the gas flow to the burner 15.
A description of the operation of the thermostatic water temperature control of the instantaneous water heater follows:
The sensor bulb 43 senses the water temperature in a suitable part of the coil 4 and the consequent increase or decrease in the volume of the liquid or gaseous medium inside the bulb 43 and capillary tube 42 controls the movement of the conical end 40 of the thermostatic bellows 41, which is attached to the bottom part of the diaphragm valve. This conical end 40 moves forward or backward relative to the perforated pin 37 that forms part of the temperature setting knob 38, which is suitably graduated for the convenience of the user.
When the temperature setting is increased (by the counterclockwise turning of said knob 38) the threaded portion 39 determines the position of the perforated pin 37 and the conical end 40 of the thermostat is forced to travel further before seating on the mouth of said perforated pin 37.
As the conical end 40 moves toward the open end of said perforated pin 37 (due to an increase in the temperature of the water sensed by the sensor bulb 43) the gas flow from the upper chamber 16 and the lower chamber 17, through the ducts 35, 36, 48 and the nozzles 9 and 10 is restricted, thus producing a pressure increase in the bottom chamber 17 which controls the movement of the elastic diaphragm 18 and the respective restriction of the gas flow to the burner 15, producing a quick reduction of the water temperature in the heating coil 4 and the outlet pipe 51.
The water temperature reduction is sensed by the bulb 43 and the respective reaction of the thermostatic means is to retract the conical end 40 removing said end from the perforated pin 37, allowing a larger flow of gas through the chamber 47 and reducing the pressure in the bottom chamber 17, thus allowing the opening of the diaphragm, due to pressure in the upper chamber 16, and increasing the gas flow to the burner 15, which in turn causes the water temperature to increase until the high water temperature causes the restriction of the gas flow to the chamber 47 and the reduction of the gas flow to the burner 15. The above mentioned cycle is repeated again and again while the water heater is in operation and the "response" (reaction time to the temperature changes) is so fast and accurate that it has been found under operating conditions the temperature of the outlet water is constant through the entire range of the system (from 30° to 60°C).
It must be noted that even if the conical end 40 of the thermostat fully closes the outlet of the gas exhausted through the perforated pin 37, the burner 15 is not totally turned off because a minimal amount of gas keeps flowing from the duct 35 to the ducts 36 and 48 through the small diameter orifices 37a of the perforated pin 37 so as to maintain a small pressure differential between the upper chamber 16 and the bottom chamber 17 of the diaphragm valve, thus allowing a small gas flow from inlet 20 to the burner 15.
The volume of this small gas flow (which produces a "minimum flame") can be easily regulated by adjusting the setting of the "minimum flame screw" 45 to decrease or increase the flow of the gas drainage from the upper to the bottom chamber of the diaphragm valve.
It is interesting to note that the improved control device disclosed in this description does not require mechanical linkages to interconnect the component parts of the device, thus eliminating the usual problems encountered in conventional control systems, such as stuck pins, bent levers, rusted pins or levers, damaged seals producing water and/or gas leaks, and so on, because there is no physical connection or communication between the gas and water circuit portions.
It is also necessary to keep in mind that the device according to the present invention may be modified as to detail so as to adapt this novel control device to an economical manufacturing process, without departing from the spirit and scope of invention as claimed in the following claims.
The object of the present invention is to improve the magnetic-mechanical valves or devices employed for the control of the gas flow in instantaneous water heaters, as disclosed in U.S. Pat. No. 3,806,026, dated Apr. 23, 1974.
The devices disclosed in said patent represented a substantial improvement and novelty in the field of the gas flow control devices for water heaters because by the use of a novel magnetic device comprising a hollow magnetic piston and a set of permanent magnets mounted on the arms of a tilting lever, the invention provided for both the progressive lighting of the water heater burner and the instantaneous cut-off of said burner in the event no water is flowing.
In addition to the above mentioned feature, a novel thermostatic device provided a constant "modulation"of the burner flame, at the user's option, as a function of the water flow, preventing the over-heating of the heat-exchanger coil, and eliminating all the problems usually encountered in conventional water heaters.
Practical use has shown that despite the fact that the system disclosed in said U.S. Pat. No. 3,806,026 is sufficiently efficient to serve all the above purposes, the additional modification and improvements according to the present invention provide a simpler system which operates more satisfactorily and costs less to manufacture.
Fundamentally, the improved device which is the object of the present invention comprises a novel assembly of magnetic elements controlling the opening or closing of a diaphragm type main gas valve, which can be regulated through its entire opening range by means of a novel thermostatic control system.
To additionally provide a high degree of safety, the improved valve according to the invention is provided with a failsafe system, using a thermocouple (which is not in itself the object of this invention) which in turn controls a magnetic coil that prevents the lighting of the main burner in the event the "pilot-flame"is not lighted.
The following is a description, as an illustrative example, of a preferred embodiment of the present invention, with reference to the accompanying drawing which is a side elevation of the system with the magnetic device and the improved diaphragm valve shown in section.
As illustrated in the FIGURE at the left side of the drawing there is a hollow metal body 1 connected at its two ends to the inlet and outlet ducts 2 and 3 through which the water to be heated in the heat-exchanger coil 4 of the instantaneous water heater circulates.
Inside the hollow body 1 are stop rings 5 and 6 limiting the axial movement of the hollow piston 7, which is formed by a permanent magnet.
As disclosed in U.S. Pat. No. 3,806,026, the magnetic hollow piston 7 moves upwardly or downwardly inside the body 1 in dependence on the flow of water through the ducts 2 and 3. When the flow increases, the magnetic piston 7 will move upwardly until it abuts against the stop ring 6, and, conversely, the piston 7 will move downwardly when the flow decreases until it is seated on the bottom ring 5 when the flow stops.
The broken lines show the piston 7 at its bottom position when there is no flow in duct 2, and the solid lines show said piston in its upper position when the water is flowing.
A second, short, hollow metal body 8 projects from the center part of the hollow metal body 1, at a right angle relative to the geometrical axis of the body 1. The body 8 has inlet and outlet nozzles 9 and 10 respectively for discharging the gas flow from the diaphragm valve.
Inside the hollow body 8 is a solid magnetic piston 11 having its North pole facing the North pole of the magnetic piston 7, across the wall of the body 1 when the piston 7 is at its bottom position.
The other end of the piston 11 (i.e., its South pole) is provided with an elastic disc 12 made of rubber, neoprene or the like, the position of which permits or prevents the flow of the gas through the nozzles 9 and 10. The nozzle 10 projects into the body 8 forming a seat 13 for the resilient disc 12 and providing a gas-tight seal when the magnetic piston 11 is remote from the magnetic hollow piston 7 due to the magnetic repulsion produced when the North poles of both magnets 7 and 11 are facing each other.
This assembly -- which is controlled by the fluctuations in the stream of water flowing through the instantaneous water heater, which fluctuations are produced by the user or being caused by variations in flow in the water mains, controls a diaphragm type gas valve 14, which in turn controls the gas feed to the burner 15.
The diaphragm valve 14 comprises an upper chamber 16 and a lower chamber 17, separated by a diaphragm 18 made of a resilient material, said diaphragm having in its center a closure disc 19 made of metallic or resilient material. The gas inlet 20 opens into the upper chamber 16 which has in one wall the seat 21 for the closure disc 19 of the diaphragm 18. Between the gas inlet 20 and the seat or nozzle 21 is a closure valve 22 biased closed by a spring but held open by a solenoid 23 activated by a thermoelectric device 24 responsive to the pilot flame 25 when that flame is lit. In the upper part of the valve body 14 is located the conical gas valve 26 defining a duct or orifice 27 leading to the pilot flame 25.
The stem and body of the conical valve 26 are axially perforated to accommodate a pin 28 ending in a knob 29. The pin 28 is biassed by the helical spring 30 away from the closure valve 22 which, when seated on seat 22a, interrupts the gas flow. To initially permit the flow of gas to the "pilot" 25 it is necessary to press the knob 29 inward, and this can be done only when the conical valve 26 is closed, because of the half 29a of said knob which must be introduced in a corresponding slot in the knob 29b of the conical valve 26. In the lower valve chamber 17 is a novel ignition retarding valve comprising a box 31 having orifices 32 in its upper part. Inside the box 31 is a small disc 33, made of metal or other material, having at least one small orifice 34 therein.
The lower chamber 17 and the upper chamber 16 of the diaphragm valve are connected by a duct 35 connected to a duct 36 which in turn connects the ignition retarding valve 31 with the perforated pin 37 of the temperature regulator 38 located in the lower part of the valve 14.
The temperature regulator 38a comprises a threaded portion 39 adapted to be rotated by the knob 38 to permit the forward or backward movement of the perforated pin 37 relative to the conical end 40 of the thermostat 41 which is connected to the capillary tube 42 connected to a bulb 43 suitably immersed in the heat-exchanger coil 4 of the instantaneous water heater in order to sense the water temperature.
The duct 36 in the lower body 17 of the diaphragm valve leads to a duct 44 which receives a regulating screw 45 to regulate the "minimum flame."
The duct 44 is connected to the outlet nozzle 46 which is also connected to the chamber 47 containing the conical end 40 of the thermostat and the end of the perforated body 37 of the temperature regulator.
The outlet nozzle 46 is connected to the nozzle 9 of the hollow body 8 through a duct 48 having a small diameter, and the outlet nozzle 10 of the body 8 is connected to the conical valve 26 through a tube 49 likewise having a small diameter.
In operation, the control valve assembly according to this invention operates as follows:
a. When the valve 22 is opened, by depressing the knob 29 to ignite the pilot, the combustible gas enters the diaphragm valve 14 through the gas inlet 20, thus filling the upper chamber 16, and flows through the duct 35 to duct 36 and thence through the "ignition retarding valve" 31 to fill the lower chamber 17.
b. When the flow of water to the water heater is interrupted, the hollow magnetic piston 7 is on its bottom position 5 and the repulsion between the North pole of the magnet 7 and the North pole of the magnetic piston 11 urges the closure disc 12 against its seat 13, preventing gas flow between the lower chamber 17 of the diaphragm valve 14 and the ducts 48, 49 to the burner 15.
c. When the seat 13 is covered by the closure disc 12 of the magnetic piston 11, the pressure in the lower chamber 17 and the upper chamber 16 is equalized and the spring forces the diaphragm 18 and the closure disc 19 to seat against the seat 21, interrupting gas flow to the burner 15 from the upper chamber 16.
d. When a predetermined stream of water flows through the hollow body 1, the hollow magnetic piston 7 moves from its bottom position 5 to its upper position 6, and the South pole of the magnetic piston 7 faces the North pole of the magnet 11 located in the hollow metal body 8, thus producing a magnetic attraction and withdraws the closure disc 12 (attached to the South pole of said magnet 11) from its seat 13 permitting communication between the gas nozzles 9 and 10 and permitting the exhaust of the gas accumulated in the lower chamber 17 of the diaphragm valve 14, which gas flows through the ducts 48 and 49 to the main heater of the burner 15, if and when the conical valve 26 is in its "open position."
e. On the other hand, due to this gas exhaustion a pressure reduction is produced in the lower chamber 17 relative to the pressure in the upper chamber 16, so that the diaphragm 18 moves downward to open the seat 21 and allow the flow of gas to the burner 15.
When the lower chamber 17 is connected to the burner 15 through the conical valve 26, a gas exhaust is produced and the disc 33 is seated against the seat at the end of the duct 36 and the gas accumulated in the lower chamber 17 is slowly released through the small diameter orifice 34 of the disc 33.
f. The slow release of the accumulated gas permits the diaphragm 18 to gradually uncover the opening of the duct 21, so that the ignition of the burner 15 is produced slowly as the lower chamber 17 of the diaphragm valve is emptied, thus preventing the sudden ignition of the burner. This is advantageous because there is no sooting of the burner and no detonation noise.
g. When the water flow through the duct 2 decreases for any reason, or if said flow is completely interrupted, the hollow magnetic piston 7 descends to its bottom position, and the magnetic attraction exerted on the magnetic piston 11 is replaced by a magnetic repulsion that reaches its maximum intensity when the magnetic piston 7 is at its lowermost position.
The movement of the magnetic piston 11, in dependence on the water flow variations controls the passage of the gas between the nozzles 9 and 10 thus controlling the passage of gas to the burner 15, because when the flow of gas from the lower chamber through the duct 48 is interrupted, the gas pressure will be equalized inside both chambers 16 and 17, forcing the rapid movement of the diaphragm to close the inlet 21 and interrupting the gas flow to the burner 15.
A description of the operation of the thermostatic water temperature control of the instantaneous water heater follows:
The sensor bulb 43 senses the water temperature in a suitable part of the coil 4 and the consequent increase or decrease in the volume of the liquid or gaseous medium inside the bulb 43 and capillary tube 42 controls the movement of the conical end 40 of the thermostatic bellows 41, which is attached to the bottom part of the diaphragm valve. This conical end 40 moves forward or backward relative to the perforated pin 37 that forms part of the temperature setting knob 38, which is suitably graduated for the convenience of the user.
When the temperature setting is increased (by the counterclockwise turning of said knob 38) the threaded portion 39 determines the position of the perforated pin 37 and the conical end 40 of the thermostat is forced to travel further before seating on the mouth of said perforated pin 37.
As the conical end 40 moves toward the open end of said perforated pin 37 (due to an increase in the temperature of the water sensed by the sensor bulb 43) the gas flow from the upper chamber 16 and the lower chamber 17, through the ducts 35, 36, 48 and the nozzles 9 and 10 is restricted, thus producing a pressure increase in the bottom chamber 17 which controls the movement of the elastic diaphragm 18 and the respective restriction of the gas flow to the burner 15, producing a quick reduction of the water temperature in the heating coil 4 and the outlet pipe 51.
The water temperature reduction is sensed by the bulb 43 and the respective reaction of the thermostatic means is to retract the conical end 40 removing said end from the perforated pin 37, allowing a larger flow of gas through the chamber 47 and reducing the pressure in the bottom chamber 17, thus allowing the opening of the diaphragm, due to pressure in the upper chamber 16, and increasing the gas flow to the burner 15, which in turn causes the water temperature to increase until the high water temperature causes the restriction of the gas flow to the chamber 47 and the reduction of the gas flow to the burner 15. The above mentioned cycle is repeated again and again while the water heater is in operation and the "response" (reaction time to the temperature changes) is so fast and accurate that it has been found under operating conditions the temperature of the outlet water is constant through the entire range of the system (from 30° to 60°C).
It must be noted that even if the conical end 40 of the thermostat fully closes the outlet of the gas exhausted through the perforated pin 37, the burner 15 is not totally turned off because a minimal amount of gas keeps flowing from the duct 35 to the ducts 36 and 48 through the small diameter orifices 37a of the perforated pin 37 so as to maintain a small pressure differential between the upper chamber 16 and the bottom chamber 17 of the diaphragm valve, thus allowing a small gas flow from inlet 20 to the burner 15.
The volume of this small gas flow (which produces a "minimum flame") can be easily regulated by adjusting the setting of the "minimum flame screw" 45 to decrease or increase the flow of the gas drainage from the upper to the bottom chamber of the diaphragm valve.
It is interesting to note that the improved control device disclosed in this description does not require mechanical linkages to interconnect the component parts of the device, thus eliminating the usual problems encountered in conventional control systems, such as stuck pins, bent levers, rusted pins or levers, damaged seals producing water and/or gas leaks, and so on, because there is no physical connection or communication between the gas and water circuit portions.
It is also necessary to keep in mind that the device according to the present invention may be modified as to detail so as to adapt this novel control device to an economical manufacturing process, without departing from the spirit and scope of invention as claimed in the following claims.