US3118602A

US3118602A - Gas burner control

Info

Publication number: US3118602A
Authority: US
Inventors: Avy L Miller
Original assignee: Individual
Current assignee: TDY Industries LLC
Priority date: 1961-08-28
Filing date: 1961-08-28
Publication date: 1964-01-21
Anticipated expiration: 1981-01-21

Description

Jan. 21, 1964 A. 1.. MILLER GAS BURNER CONTROL Filed Aug. 28, 1961 m M T e M m e w m I M 1 United States The present invention relates to heater controls, and more particularly to the control of the fuel supply to gas burning heaters.

In the operation of gas burning heaters it is sometimes desired to operate the burner for the heater at less than its maximum or high fire rate. One example only of such operation is in the case of continuous flow heaters where fluid flow through the heater may be substantially con- Stant and heat supplied thereto in accordance with the temperature of the fluid as it enters the heater and the desired delivery temperature. Thus, if the entering fluid is at or above the desired delivery temperature, the burner of the heater is shut off and no heat added to the fluid. Should the temperature of the fluid entering the heater be only moderately less than the desired delivery temperature, it is desired to operate the burner at less than its maximum or high fire rate to avoid overheating the fiuid passing through the heater.

When such low fire operation is desired for the burner, difliculty may be experienced in initiating combustion of the low flow of fuel gas corresponding to this low fire operation, and such low gas flow starting may be accompanied by accumulations of gas in the heater and attendant violent ignition, or only a portion of the burner orifices may have the gas flowing therethrough ignited, with a portion of the fuel flowing out the flue without burning so that the operation of the burner and utilization of the fuel is uneconomical. These difficulties are overcome, according to the present invention, by incorporating into the control of the fuel gas for the burner, means for in? suring starting of combustion at the bur er under high fire conditions. That is, by supplying fuel gas to the burner at a high flow rate for starting, with subsequent operation of the burner at a desired reduced rate of flow after combustion has been initiated.

If the temperature of the incoming fluid to be heated is sufliciently low, it is desired to stay at the high fire rate for operation of the burner subsequent to initiation of combustion, and the control of the present invention provides for this manner of operation as well.

It is, therefore, an object of the present invention to provide an improved control for gas burner fuel insuring high fire starting of combustion at the burner.

Another object of this invention is the provision of an improved gas control for burners supplying fuel gas there to at a high rate to initiate combustion and automatically lowering the fuel flow rate for subsequent, reduced fire operation.

A further object of this invention is the provision of an improved valve for the control of fuel to gas burners which insures immediate and complete initiation of combustion at the burner, regardless of the fire level at which the burner is to operate.

A still further object of this invention is the provision of an improved gas burner control supplying fuel at a high fire rate to initiate combustion, and thereafter automatically reducing the fuel flow to the rate called for by the heat to be supplied to the burner.

These and other objects and features of the invention will be readily apparent to those skilled in the art from the following specification and the appended drawing, in which:

The figure is a schematic representation of a gas burner control according to the present invention.

The drawing schematically illustrates a control according to the present invention feeding gaseous fuel from a atent O source through a conduit 11, a main control valve 12, and a conduit 13, to a gas burner 14. The main control valve 12 employs an outer casing made up of three sections: 2. lower, generally cup-shaped section 15; an intermediate, ring-shaped section 16; and an upper, inverted cup-shaped section 17. Between the intermediate section 16 and the lower and upper cup-shaped sections 15 and 17 are disposed operating diaphragms 18 and 19, in seal ing relation therewith, to form thereby three superimposed chambers 21, 22 and 23.

The conduit 11 feeds the fuel gas from the source directly into chamber 21. The conduit 13 receives the gaseous fuel from an outlet passage 24 communicating with the chamber 21 through a valve outlet portion 25. The outlet valve portion 25 is controlled by a plate 26 mounted on the lower surface of the diaphragm 19 to be controlled thereby. A weight plate 27 is mounted on the upper surface of the diaphragm 19, and a similar plate 28 is mounted on the upper surface of the diaphragm 18. A stop screw 29 is adjustably threaded into the plate 28 and presents an abutment at the end thereof engageable with the plate 27. An inlet pipe 31 feeds from the main supply conduit 11 to the chamber 2.2 through a restricted passage 32. A pipe 33 feeds from the conduit l3 immediately downstream of the valve 12 through a restricted passage 34 to a pipe 35 communicating with the chamber 23.

A pipe 53 connects the chamber 22 with the stationary element 36 of a first control valve 37 which has a movable sealing plate 38 cooperating with the stationary valve element 36 to effect the valving action. The plate 38 is mounted on an arm 39 pivoted at 41 within a housing 42 about the control valve. The housing 42 is made gastight by a cover '43 sealingly attached thereto. Also mounted within the housing 42 is a second control valve 44 comprised of a stationary element 47 and a movable sealing plate 48 mounted on the arm 39 by a lost motion connection 49. A finger spring 51 on the arm 39 biases the plate 43 toward valve closing position. The valve element 47 of the second control valve 44 is connected to the chamber 23 through the pipe 35. A pipe 54 provides an outlet from the interior of the housing 42 to the burner.

A thermostatic element 55 is shown immersed in a fluid 56 flowing through a passage 57, the temperature of the fluid determining the operation of the control valves 37 and 44. The thermostatic element 55 includes an operator 5'8 extensible and contractible in accordance with the temperature of the fluid in which the thermostatic element is immersed and pivotally attached at 59 to the end of the arm 39. Thus, as the operator 58 retracts on a lowering of the temperature of the fluid 56, it will cause rotation of the arm 39 in a counterclockwise direction to open the valves 37 and 44.

It will be understood that the passage 57 for the fluid 56 will normally communicate with heat exchange means across which are directed the products of combustion from the burner 14. However, the invention is not limited to any particular heater or type of heat transfer or medium to be heated, but is directed generally to the control of fuel gas to insure high fire starting of combustion at a gas burner regardless of the fire level at which it is to operate.

In the drawing, the parts of the control according to the present invention are shown in the positions which they assume during low fire operation of the burner, with the fuel gas being supplied at a rate lower than for high fire operation. This position of the parts is determined by the temperature of the fluid 56 which, acting through the thermostatic element 55, has effected movement of the operator 53 to rotate the arm 39 only sufficiently to move the sealing plate 38 away from the valve element 36, while the valve 4-4 remains closed by the engagement of the sealing plate 43 with the valve element 47 through the lost motion connection 4?.

In the position of the partsillustrated in the drawing, the chamber 22 is at reduced pressure since the valve 37 is open to communicate it to atmosphere at the burner 14, through the pipe 53, the interior of the housing 42, and the pipe 54. Since the valve 44 is closed, the chamber 23 .carmot exhaust to atmospheric pressure through the pipe 35, but the pressure therein is maintained at the value of the gas pressure with n the conduit 13 just downstream of the valve 12, through the restricted opening 34, pipe 33 and the portion of pipe 35 between the pipe 33 and the valve section 17. The diaphragm 19 tends to move upwardly under the force exerted by the pressure within thet chamber 21 from the gas supply, as modulated through the valve portion 25, since the chamber 22 is at reduced pressure, being exhausted to atmosphere as above described and being supplied only through the restricted passage 32. However, in moving upwardly, the weight plate 27 engages the end of the screw 2? as an abutment, and is prevented from moving upwardly further by the pressure within the chamber 23. Therefore, the valve plate 26 stops in an intermediate position between valve closed and valve fully open, as determined by the setting of the screw 29, to limit the amount of gaseous fuel passing through the valve 12 to that producing the desired low fire at the burner 1 A fixed abutment limiting downward movement of diaphragm 18 may be provided, if desired, but is not essential.

If, while operating at low fire as illustrated in the drawing, the temperature of fiuid 56 should decline further, thermostatic element 55' will call for high fire operation by retracting operator 58 to rotate the arm 39 further in a counterclockwise direction and move valve sealing plate 43 away from the valve element 47, thus opening valve This communicates the chamber 23 to atmosphere at the burner 14 through pipe 35, Valve 44, the interior of housing 42, and pipe 54-. The pressure within chamber 23 therefore declines to substantially atmospheric, in view of the limited supply through the restricted passage 34, and diaphragm 13 moves upwardly with diaphragm 19 under the force exerted by the pressure within the chamber 21. This upward movement of the diaphragm 1? moves the valve sealing plate 26 further upwardly and opens the valve portion 25 wide to permit maximum fiow of gaseous fuel to product high fire operation at the burner 14. Therefore, depending upon the response of the thermostatic element 55, the burner 14 will be supplied with fuel at either a low flow rate or a igh fiow rate for continuous low fire or high fire operation, as called for by the thermostatic element.

In the exemplification shown in the drawing, should the temperature of the fiuid 56 entering the heater rise to a sufficiently high value, the thermostatic element will extend the operator 58 to rotate the arm 3? clockwise and close both the control valves 37 and 44. his closes the exhausts from chambers 22 and 23 therethrough, and the pressure within chamber 22 will rise' to substantially full line pressure, being fed from the supply conduit 11 through restricted passage 32. The pressure above the diaphragm 19 will then be greater than the pressure therebeneath, and this coupled with the Weight of the plate 2-? will move the diaphragm l9 downwardly to cause the sealing plate as to engage the valve portion 25 and close the exit passageway 24, thus shutting off the fiow of fuel to the burner 14. With the closing of the valve portion 25, conduit 13 returns to atmospheric pressure through the burner nozzle, and chamber 23 is at atmospheric pressure the restricted passage 34-. Diaphragm 18 will move upwardly, in view of the line pressure in' chamber 22 on the lower side thereof and will move stop screw 29 therewith.

With the valve 12 closed, should the temperature of the fluid 56 decline to a point calling for the supply of heat 4 at a low rate thereto, the thermostatic element 55 will retract the operator 58 to rotate arm 39 sufficiently to open valve 37 only, to call for low fire operation of the burner 14. This will exhaust chamber 22 to atmosphere at the burner 14, as previously described, and the pressure on the rep side of the diaphragm 19 being thus removed, the pressure on the lower side thereof from chamber 21 will move it upwardly. Since, as previously explained, the chamber 23 is at atmospheric pressure through the restricted passage 34, conduit 13 and the burner nozzle, the diaphragm 19 will move upwardly to its full open position, permitting maximum flow of fuel through the valve 12 to the burner 14 to effect high fire starting of combustion thereat. Ignition at the burner may be accomplished by a pilot flame, an electrical spark, or any other conventional means. Thus, although the signal from the thermostatic element 55 is for low fire operation of the burner 14, initially the valve 12 passes a maximum flow of fuel to the burner to secure starting at high fire.

After the valve 12 opens, pressure builds up within the chamber 23 with a time delay from the conduit 13 through the restricted passage 34, to move the diaphragm 18 downwardly into the position illustrated in the drawing. in this downward movement of the diaphragm 13, the .end of screw 29 engages the plate 27 and forces the diaphragm 19 downwardly into the position shown where the valve plate 2s is in an intermediate position modulating the fuel flow through the valve to a lower value producing low fire operation at the burner 14. Thereafter, the burner continues to operate at the low fire rate until the thermostatic element 55 changes its signal to call for high fire operation or for shutoff of the burner 14.

Should the temperature of the fluid 56 initially decline to a low value where high fire operation is called for, the thermostatic element 55 retracts the operator 58 sufficiently to move the arm 39 to open both valves 37 and 4-4, thus connecting both chambers 22 and 23 to atmosphere at the burner 14 through their respective pipes '53 and 55. The valve 12 under this condition opens as before to supply maximum fuel flow and high fire starting of the burner but the pressure within the chamber 23 does not increase since it is connected to atmosphere through the open control valve 44. The diaphragm i9 remains in its uppermost position, with the valve sealing plate 26 at maximum separation from the valve portion 25, and the burner 14 operates at high fire until the thermostatic element 55 calls for a change.

Thus, the control according to the present invention provides for operation of a heater burner at a selected combustion rate or fire level but supplies fuel to the burner at maximum or high fire rate to initiate combustion and then automatically reduces the fuel flow if a lower rate of combustion is called for. The control provides for continuous operation of a gas burner at either a low fire rate of combustion or a high fire rate of combustion, on command, but automatically supplies fuel to the burner to initiate combustion at the high fire rate, regardless of the level of combustion called for by the command signal. If the burner is always to operate at a constant level, the control will still increase the fuel flow reate for starting combustiom and in this mode of operation the valve 44 may be entirely omitted and the pipe 35 sealed off at its connection to the pipe 33. In the operation of this latter control, the fuel control valve '12 will always return to the desired constant level of fuel supply with a time delay after supplying fuel at maxim m to initiate combustion.

While a certain preferred embodiment of the invention has been schematically illustrated in the drawing and described herein, it will be understood that the invention is not limited thereto, as many variations will be apparent to those skilled in the art, and the invention is to be given its broadest interpretation within the terms of the following claims.

I claim:

1. A gas burner control comprising: a main fuel control valve comprising a casing; a pair of movable diaphragms dividing said easing into three successive chambers, the outer cahmbers being each bounded by one of said diaphragms and the intermediate chambers being bounded by both of said diaphragms, one of said outside chambers having the main fuel control valve therein and controlled by the position of its associated diaphragm; an unrestricted fuel inlet to said one outside chamber; an unrestricted fuel outlet from said fuel control valve adapted to lead to a burner; means feeding fuel gas from the supply through a restricted passage to said intermediate chamber; an exhaust passage from said intermediate chamber; condition responsive means for opening and closing the exhaust passage from said intermediate chamber to de termine the pressure therein and the position of the valve controlling diaphragm; means continually connecting the other outside chamber to a point closely adjacent to the valve outlet through a restricted passage to provide a time delay in build up of pressure in said other outside chamber after opening of the valve; and means on said diaphragms limiting their movement toward each other.

2. A gas burner control comprising: a main fuel control valve comprising a casing; a pair of movable diaphragms dividing said easing into three successive chambers, the outer chambers being each bounded by one of said diaphragms and the intermediate chamber being bounded by both of said diaphragms, one of said outside chambers having the main fuel control valve therein and controlled by the position of its associated diaphragm; an unrestricted fuel inlet to said one outside chamber; an unrestricted fuel outlet from said fuel control valve adapted to lead to a burner; means feeding fuel gas from the supply through a restricted passage to said intermediate chamber; an exhaust passage from said intermediate chamber; condition responsive means for opening and closing the exhaust passage from said intermediate chamber to determine the pressure therein and the position of the valve controlling diaphragm; means continually connecting the other outside chamber to a point closely adjacent to the valve outlet through a second restricted passage; and interengaging abutment means on said diaphragms limiting their movement toward each other, said other outside chamber always being at atmospheric pressure when the valve is closed and permitting movement of its associated diaphragm with the valve controlling diaphragm for maximum valve opening upon initial opening of the exhaust passage from the intermediate chamber, the pressure within said other outside chamber building up through the second restricted pas sage with a time delay after valve opening to move the diaphragrns toward valve closing position and modulate the rate or" flow of fuel through the valve to an operating value less than said starting value.

3. A gas burner control comprising: a main fuel control valve comprising a casing; a pair of movable diaphragms dividing said casing into three successive chambers, the outer chambers being each bounded by one of said diaphragms and the intermediate chamber being bounded by both of said diaphragms, one of said outside chambers having the main fuel control valve therein and controlled by the position of its associated diaphragm; an unrestricted fuel inlet to said one outside chamber; an unrestricted fuel outlet from said fuel control valve adapted to lead to a burner; means feeding fuel gas from the supply through :a restricted passage to said intermediate chamber; an exhaust passage from said intermediate chamber; condition responsive means for opening and closing the exhaust passage from said intermediate chamber to determine the pressure therein and the position of the valve controlling diaphragm; means connecting the other outside chwiber to the valve outlet through a second restricted passage; interengaging abutment means on said diaphragms limiting their movement toward each other, said other outside chamber being at atmospheric pressure when the valve is closed and permitting movement of its associated diaphragm with the valve controlling diaphragm for maximum valve opening upon initial opening of the exhaust passage from the intermediate chamber, the pressure within said other outside chamber building up from the valve outlet through the second restricted passage with a time delay after valve opening to move the diaphragms toward valve closing position and modulate the rate of flow of fuel through the valve to an operating value less than said starting value; an exhaust passage from said other outside chamber; and means for opening said last mentioned exhaust passage to prevent build up of pressure within said other outside chamber and maintain the operating flow of fuel at the starting rate.

4. A gas burner control comprising: a main fuel control valve comprising a casing; a pair of movable diaphragms dividing said easing into three successive chambers, the outer chambers being each bounded by one of said diaphragms and the intermediate chamber being bounded by both of said diaphragms, one of said outside chambers having the main fuel control valve therein and controlled by the position of its associated diaphragm; an unrestricted fuel inlet to said one outside chamber; an unrestricted fuel outlet from said fuel control valve adapted to lead to a burner; means feeding fuel gas from the supply through a restricted passage to said intermediate chamber; an exhaust passage from said intermediate chamber; condition responsive means for opening and closing the exhaust passage from said intermediate chamber to determine the pressure therein and the position of the valve controlling diaphragm; means connecting the other outside chamber to the valve outlet through a second restricted passage; interengaging abut-ment means on said diaphragms limiting their movement toward each other, said other outside chamber being at atmospheric pressure when the valve is closed and permitting movement of its associated diaphragm with the valve controlling diaphragm for maximum valve opening upon initial opening of the exhaust passage from the intermediate chamber, the pres sure within said other outside chamber building up through the second restricted passage with a time delay after valve opening to move the diaphragms toward valve closing position and modulate the rate of fiow of fuel through the valve to an operating value less than said starting value; an exhaust passage from said other outside chamber; and means for opening said last mentioned exhaust passage to prevent build up of pressure within said other outside chamber and maintain the operating flow of fuel at the starting rate, said condition responsive means and exhaust passage controlling means comprising thermostatic valves individual to said chambers controlling said chamber exhaust passages .in accordance with the level of the temperature condition to which they are responsive.

5. A gas burner control comprising: a main fuel control valve comprising a casing; a pair of movable diaphragms dividing said casing into three successive chambers, the outer chambers being each bounded by one of said diaphragms and the intermediate chamber being bounded by both of said diaphrams, one of said outside chambers having the main fuel control valve therein and controled by the position of its associated diaphragm; an unrestricted fuel inlet to said one outside chamber; an unrestricted fuel outlet from said fuel control valve adapted to lead to a burner; means feeding fuel gas from the supply through a restricted passage to said intermediate chamber; an exhaust passage from said intermediate chamber; condition responsive means for opening and closing the exhaust passage from said intermediate chamber to determine the pressure therein and the position of the valve controlling diaphragm; means connecting the other outside chamber to the valve outlet through a second restricted passage; interengaging abutment means on said diaphragms limiting their movement toward each other, said other outside chamber being at atmospheric pressure when the valve is closed and permitting movement of its associated diaphragm with the valve controlling diaphragm for maximum valve opening upon initial opening of the efiaust passage from the intermediate chamber, the pressure Within said other outside chamber building up from the valve outlet through the second restricted passage with a time interval after valve opening to move the diaphragms toward valve closing position and modulate the rate of flow of fuel through the valve to an operating value less than said starting value; an exhaust passage from said other outside chamber; and means for opening said last mentioned exhaust passage -to prevent build up of pressure within said other outside chamber and maintain the operating flow of fuel at the starting rate, said condition responsive and exhaust passage controlling means comprising a thermostatic element and a pair of valves individual to said chamber exhaust passages and operated by said thermostatic element in sequence in accordance with the level of the temperature condition to which it is responsive to call for either high fire or low fire continuous operation of the burner, and said fuel control valve operating automatically regardless of the level of the temperature condition and the continuous fire operation cmled for to initially supply fuel to the burner at the maximum high fire rate for starting combustion.

6. A gas control valve comprising: a housing having a pair of spaced diaphragms therein dividing the interior of the housing into three successive separated chambers; a gas control valve in one outside chamber including an operating member carried by the diaphragm associated therewith; an abutment surface on said valve operating diaphragm directed away from the valve; a

stop mounted on the other diaphragm directed toward and a control passage from at least said intermediate chamber.

7. A gas burner control comprising: a casing; a pair of movable diaphragms dividing said casing into three successive chambers, the outer chambers being each bounded by one of said diaphragms and the intermediate chamber being bounded by both of said diaphragms; a

main fuel control valve; means controlling said main valve by the position of one of said diaphragms; an unrestricted fuel inlet from the supply to the outside chamber bounded by said last mentioned diaphragm; an outposition of the main valve controlling diaphragm; means connecting the other outside chamber to the valve outlet through a restricted passage providing for a time interval after opening of the valve before pressure builds up in said other outside chamber; and means on said diaphragrns limiting their movement toward each other.

8. A gas burner control col prising: a casing; a pair of movable diaphragms dividing said casing into three successive chambers, the outer chambers being each bounded by one of said diaphragms and the intermediate chamber being bounded by both of said diaphragms; a main fuel control valve; means controlling said main'valve by the position of one of said diaphragms; an unrestricted fuel inlet from the supply to the outside chamber bounded by said last mentioned diaphragm; an outlet from said last mentioned chamber through the main valve; a restricted fuel inlet from the supply to the intermediate chamber; an exhaust passage from said intermediate chamber; condition responsive means for opening and closing the exhaust passage from said intermediate chamber to determine the pressure therein and the position of the main valve controlling diaphragm; means connecting the other outside chamber to the valve outlet through a restricted passage providing for a time interval after opening of the valve before pressure builds up in said other outside chamber; an exhaust passage from said other outside chamber; and means under the control of said condition responsive means for opening and closing said last mentioned exhaust passage.

References Cited in the fileof this patent UNITED STATES PATENTS 1,956,977 Shawn May 1, 1934 2,051,295 Gauger Aug. 18, 1936 2,071,871 Cleveland Feb. 23, 1937 2,164,511 Furlong July 4, 1939 2,318,228 Jones May 4, 1943 2,328,279 Jones Aug. 31, 1943 2,490,420 Davis Dec. 6, 1949 2,924,387 Hajny Feb. 9, 1960

Claims

1. A GAS BURNER CONTROL COMPRISING: A MAIN FUEL CONTROL VALVE COMPRISING A CASING; A PAIR OF MOVABLE DIAPHRAGMS DIVIDING SAID CASING INTO THREE SUCCESSIVE CHAMBERS, THE OUTER CHAMBERS BEING EACH BOUNDED BY ONE OF SAID DIAPHRAGMS AND THE INTERMEDIATE CHAMBERS BEING BOUNDED BY BOTH OF SAID DIAPHRAGMS, ONE OF SAID OUTSIDE CHAMBERS HAVING THE MAIN FUEL CONTROL VALVE THEREIN AND CONTROLLED BY THE POSITION OF ITS ASSOCIATED DIAPHRAGM; AN UNRESTRICTED FUEL INLET TO SAID ONE OUTSIDE CHAMBER; AN UNRESTRICTED FUEL OUTLET FROM SAID FUEL CONTROL VALVE ADAPTED TO LEAD TO A BURNER; MEANS FEEDING FUEL GAS FROM THE SUPPLY THROUGH A RESTRICTED PASSAGE TO SAID INTERMEDIATE CHAMBER; AN EXHAUST PASSAGE FROM SAID INTERMEDIATE CHAMBER; CONDITION RESPONSIVE MEANS FOR OPENING AND CLOSING THE EXHAUST PASSAGE FROM SAID INTERMEDIATE CHAMBER TO DETERMINE THE PRESSURE THEREIN AND THE POSITION OF THE VALVE CONTROLLING DIAPHRAGM; MEANS CONTINUALLY CONNECTING THE OTHER OUTSIDE CHAMBER TO A POINT CLOSELY ADJACENT TO THE VALVE OUTLET THROUGH A RESTRICTED PASSAGE TO PROVIDE A TIME DELAY IN BUILD UP OF PRESSURE IN SAID OTHER OUTSIDE CHAMBER AFTER OPENING OF THE VALVE; AND MEANS ON SAID DIAPHRAGMS LIMITING THEIR MOVEMENT TOWARD EACH OTHER.