US2513578A - Safety shutoff control system for gas burners - Google Patents

Description

July 4, 1950 R. MATTHEWS SAFETY SHUTOFF vCONTROL. SYSTEM FOR GAS BURNERS Filed April 15, 1947 2 Sheets-Sheet 1 July 4 1950 R. MATTHEWS 2,513,573

SAFETY SHUTOFF CONTROL SYSTEM FOR GAS BURNERS Filed April 15, 1947 2 Sheets-Sheet 2 am E Patented July 4, 1950 UNITED STATES PATENT OFFICE SAFETY SHUTOFF CONTROL SYSTEM FOR GAS BURNERS Application April 15, 1947, Serial No. 741,439

14 Claims. l

This invention relates, in general, to ignition systems and has particular relation to an improved single point ignition system for fuel burners.

While the particular embodiment of the invention which I shall describe hereinafter in connection with the drawings is a single point ignition system adapted for use with domestic gas ranges, it is to be understood that the invention is not limited to such use but may be employed for all similar purposes, for example, in connection with various commercial forms of apparatus having a baking oven burner, broiler oven burner or other burner remotely located relative to the pilot burner.

In the usual domestic gas range, the pilot burner is in the form of a single constantly burning pilot located in juxtaposition to the top burners at the upper part of the range, and the baking oven, broiler or like burners are located in the lower part of the range. Although the top burners are usually provided with a constantly burning pilot burner for lighting the same, at the present time a match is usually employed for lighting the baking oven, broiler, or like burners. The stooping and hazards of lighting an oven burner or the like with a match are well known in the art.

In the copending application of Ernst Witzel, Serial No. I738,412, led March. 31, 1947, and owned by the owner of the present application there is provided an improved system of flash tubes and intermediate pilot means for assuring ignition of a pilot in juxtaposition to the oven or like burner from a constantly burning top pilot; also an improved single point ignition system wherein means is provided for extinguishing the intermediate pilot means and establishing a flow of fuel to the oven or like burner after a time delay following ignition'of the burner pilot,

the systems disclosed and claimed in the above identified copending application and in which the gas cock in the fuel supply line is the only item requiring actuation manually to secure the desired single point ignition.

One of the main objects of the present invention is to provide a simple, improved and effective single point ignition system, in general, of the character to which the last mentioned copending application is directed, and in which the main valve will close very quickly when the thermoelectric generator is not heated by its pilot.

Another object of the invention is to provide an improved form'of control in which sucient power is generated by heating of the thermoelectric generator by its pilot to move the main valve to open position, whereas upon opening of this valve the holding power of the electromagnet is reduced to an amount suicient to hold the valve open but insulcient to move it to open position.

Another object of the invention is to provide an improved arrangement of electric components comprising a resistor connected with the thermoelectric circuit; a switch responsive to the pressure in the fuel supply line, when closed, connecting the thermoelectric generator with the electromagnet around the resistor and the thermoelectric generator being connected with the electromagnet in series with the resistor when the switch is open.

Another object of the invention is to provide an improved form of thermoelectric control device for accomplishing the advantageous results set forth, and, more particularly, an improved form of combined thermoelectric valve' and switch in which the pressure for moving the switch controlling diaphragm-,to position closing the switch is neutralized for movement of the switch to open position upon opening of the main valve.

Another object of the invention is to provide a single point ignition system and instrumentallties therein, as will hereinafter appear, having various features of novelty and advantages, and which are particularly characterized by their simplicity in construction, their economy in manufacture and installation, and their elfectiveness in use.

Further objects and tion will appear from the following detailed v,description, taken in connection with the accompanying drawings which illustrate the manner of constructing and operating an illustrative embodiment of the invention.

In the drawings:

Figures 1 and 1A are parts of a diagrammatic view which, when placed with Figure 1A to the right of Figure 1 and the line B-B of Figure 1A on the line A-A of Figure 1, form a complete diagrammatic View of one form of single point ignition system embodying the present invention.

Referring now to the drawings, the burner I is the baking oven, broiler or other remote burner. It is usually located in the lower part ofv the range or other appliance.

The pilot 2 is the constantly burning pilot. It may be, for example, the top pilot for the top burners of a gas range or other constantly burning pilot. The pilot 2 is usually located in the upper part of the appliance.

A fuel supply pipe 3 leads to the burner for the delivery of gaseous or other fuel thereto, for example, through a mixing chamber 4 to which air is admitted through adjustable air inlets (not shown), as Well understood in the art. The ow of gas through the pipe 3 is controlled by a thermoelectric control valve 5 and by a gas cock 6 connected into the pipe 3 anterior of the valve 5 The oven r like burner I is provided with an oven or like pilot 1 for igniting it. A flash tube 8 has a laterally turned upper end opening directly to the constantly burning pilot 2. This tube extends downwardly and opens at its lower end t0 an intermediate pilot 9. The intermediate pilot 9 is spaced laterally from the oven pilot 1, and the tube 8 has at its lower end a generally horizontally extending branch 8' which opens at its outer end directly over the flame position I0 of the oven pilot 1.

The thermoelectric control device comprises a valve body formed of top and bottom valve body parts I5 and I6 clamped together by screws (not shown) with a diaphragm I8 therebetween. 'I'he valve body part I5 has an inlet I9 and an outlet 20. Continguous sections of the fuel supply pipe 3 are connected to the inlet I9 and outlet 20, for example, by screwing them into the inlet and outlet, which are shown as internally threaded. Internally the valve body part I5 has a generally L-shaped outlet chamber 2| having a longitudinally extending part in open communication with the outlet 20, and a transversely extending portion dened by a cylindrical wall 22. An inlet chamber 23, in open communication with the inlet I9, terminates at its inner end in a generally annular-shaped portion which embraces the cylindrical wall 22.

The Wall 22 terminates in an annular valve seat 24. An armature 25, of disc-like form, has a yielding or other suitable valve or valve facing 26 adapted to seat against the seat 24 to shut off the ow ofA gas from inlet I9 to outlet 20 through chamber 2|. A hood 21 is clamped to the valve body part I5 by a union nut 28, and preferably with a hood gasket 29 therebetween.

In the illustrated embodiment of the invention, the means for operating the valve 26, and, more particularly, the means for opening this valve, is in the form of an electromagnet comprising a magnet frame or coil spool 30 and a coil 3|. One side of the coil 3| is connected by a advantages of the inven-A of a thermocouple 34 or other suitable thermovelectric generator r(such as av thermopile). The

other element 35 of the thermocouple 34 isconnected by a leadv 36 to one contact 31 of a tilting mercury switch 38 within the valve body part I5. The other and adjacent contact 39 of the switch 38 is connected by a lead 4|! to the other side of the coil 3|.

A resistance or resistor 42 is connected in parallel with the contacts'31, 39, for example by connecting one side of the resistor to the conductor 36, at 43, and the other side of the resistor to the conductor 40, at 44. The resistor 42 is so proportioned that the electromagnet cannot open the valve 26 by lifting'the armature 25 by the heat of the pilot 1 on thermocouple 34 when the mercury switch is open at contacts 31, 39 and the thermoelectric circuit is completed only through the resistor 42. Once moved to open position however, the valve 26 will be retained open, with the switch contacts open at 31, 39. When switch 38 is closed at contacts 31, 39 the thermoelectric generator 34 is connected with the electromagnet around resistor 42, and at that time the power generated by the heat of the pilot on the thermoelectric generator is suflicient to move the valve 26 to open position.

The thermocouple 34 and lead connections therefor may be of the general character disclosed and claimed in Oscar J. Leins Patent No. 2,126,564, granted August 9, 1938, or it may be of any other suitable character, or in the form of a thermopile or other thermoelectric generator. The thermoelectric generator has one or more hot junctions, for example the hot junction 46, which is placed in position to be heated by the flame 41 of the burner pilot 1. Y

In the illustrated embodiment of the invention,

the electromagnet has a ilux shell 50 and a spacer ring 5I. The lower end of the coil spool 38 has an axial recess, and disposed in this recess and interposed between spool 30 and armature 25 is a. coiled spring 52 which operates to move armature 25 to retracted position and to seat the valve 26 on valve seat 24 when the electromagnet is deenergized. Energization of the electromagnet by heating of the hot junction of the thermocouple 34 is sufi'icient to lift valve 26 to open position against the action of spring 52 when, as already pointed out, the switch 38 is closed at the contacts 31, 39 so. that the thermoelectric circuit is completed around the resistor 42. A hood spring 53, interposed between the top of the spool 30 and hood 21, seats the shell 50 in the valve body part I5 at 54. In commercial practice, one of the thermocouple elements, for example the outer tubular thermocouple element 33, may be grounded, and one side of the coil 3| may be grounded to the valve body.

The bottom of the valve body part I5 has a recess 60 spaced inwardly from its periphery. Disposed in this recess and above diaphragm I8 is a cover plate 6| clamped to valve body part I5 by screws (not shown) with a diaphragm 62 therebetween. A port 63 opens from inlet chamdelivered from the diaphragm chamber 64 to the passage 61 through a passage 10, thelower end of which is surrounded by an annular valve seat 1 I. A valve or valve facing member 12 is adapted to seat against seat 1I to shut off the supply of fuel to the intermediate pilot 9. The burner pilot 1 is supplied with fuel by a pipe 13 connected at 14, for example, to the fuel supply pipe 3 between gas cock 6 and the thermoelectric control device 5. The constantly burning pilot 2 is supplied with fuel by a. pipe 15 connected at 18, for example, to the fuel supply pipe 3 anterior of the gas cock 6.

The diaphragm 62 may have diaphragm plates, and interposed between the bottom of this diaphragm and cover plate 6I is a spring 19. A port 88 opens from the outlet chamber 2I and through port 8| into chamber 82 beneath diaphragm 62. Passage 83 opens from outlet chamber 2| into chamber 84 beneath diaphragm I8.

The mercury bulb 38 of the mercury switch is carried by a bulb holder 85 pivoted at 86. The bulb holder has pins 88 which are engaged by the notched lower ends of the depending legs of a diaphragm bracket 89. The diaphragm I8 may have diaphragm plates, and bracket 89 is secured to the diaphragm at the axis thereof, for example, by a rivet (not shown). A spring arm 92 is notched at one end at 93 for engagement of pins 88 therein. The other end of arm 92 is notched at 94 for engagement with a pin 95. The pin 95 is carried by a spring arm bracket 96 secured to the bottom of the valve body part I6. A coiled spring 98 is interposed between the arm 92 and the base of bracket 96.

The operation of the system shown in the drawings is as follows:

When gas cock 6 is opened, gas is admitted to the tops of diaphragms 62 and I8 by means of ports 63 and 65. Valve 12 will open against the pressure of spring 19, and gas will flow to the intermediate pilot 9 through passage 61 and pipe or tube 68. Opening of gas cock 6 also admits gas to burner pilot 1 through pipe or tube 13. The gas from the intermediate and oven pilots rises in tube 8 which is always relatively cool to permit this action. As it reaches the flame of constantly burning pilot 2, the gas is ignited and then recedes or ashes back to light the intermediate and burner pilots 9 and 1. The turning of the upper end of the iiash tube laterally toward pilot 2 reduces the possibility of extinguishing this pilot by flash-back action in tube 8.

The pressure exerted on diaphragm I8 through port 65, upon opening of gas cock 6, moves the diaphragm I8 downwardly to its lowest position. This tips mercury bulb 38 in a counterclockwise direction about its pivot 86 as viewed in Figure l, suiiciently to make contact at 31, 39, thus completing the circuit between thermoelectric generator 34 and coil 3| around the resistor 42. When, with the switch 38 closed at contacts 31, 39, the electromagnet is energized suiliciently by the heat of the pilot flame 41 on thermoelectric generator 34 to lift valve 26 to open position, gas is admitted to the oven burner I through outlet A2li and fuel supply pipe 3.

help of spring 98. This breaks the electric circuit at contacts 31, 39, but the resistor 42 will maintain the circuit and hold amature 25 in attracted position and valve 26 open once it has been opened by the electromagnet.

Whenever gas cock 6 is closed, extinguishing pilot 1, the thermoelectric generator 34 is cooled. The loss of energy is suilicient to weaken or reduce the holding power of the electromagnet so that the valve 2B will move to closed position within a relatively short time since, with resistor 42 in the circuit, just enough power was maintained to hold the valve 26 in open position. In the illustrated embodiment of the invention, when thermoelectric generator 34 is not heated by pilot 1, valve 26 will close very fast, for eX- ample, in about iive seconds instead of about forty seconds with contact made at 31, 39.

As previously pointed out, the electromagnet cannot open the valve 26 with the circuit completed only through resistor 42. Contact must be closed at 31, 39 for this purpose. Once opened, the valve 26 will be retained open by the electromagnet without contact at 3l, 39.

If desired, the fuel supply pipe 3 may be provided with a thermostat valve |I8 connected, for example, by a tube ||I to a thermostat bulb ||2 located where it will be subject to the heat of the oven burner In such case, the thermostat bulb I|2 and its connected thermostat valve |I0 serve as a limit device for shutting off the iiow of hfuel to the burner I upon the occurrence of predetermined maximum temperatures. The thermostat may, of course, be adjusted to operate at different temperatures, and I contemplate other forms of thermostats and other forms 0| thermostatic controls than the one shown in the drawings, which is for purposes of illustration.

The present invention contemplates many variations in the form and details of the single point ignition system shown in the drawings, and many variations in the form and details of the electric components shown and described. The embodiment of the invention shown in the drawings is, therefore, for illustrative purposes only, and it is to be expressly understood that the drawings and the accompanying specification are not to be construed as a, definition of the limits or scope of the invention, reference being had to the appended claims for that purpose.

I claim:

1. In combination, a thermo-electrically operated valve for controlling the supply of fuel for a burner, an electromagnet for said valve, a thermoelectric generator adapted to be heated by a pilot flame and connected in circuit with said electromagnet for energizing said electromagnet to operate said valve to open position, resistor means for increasing the resistance of the circuit between the thermoelectric generator and the electromagnet, and means responsive to the opening of said valve for completing the circuit between said thermoelectric generator and said electromagnet through said resistor means to energize said electromagnet sufciently to hold said valve open but insuiiciently to open said valve.

2. In combination, a thermoelectrically operated valve for controlling the supply of fuel for a burner, an electromagnet for said valve. a thermoelectric generator adapted to be heated by a pilot flame and connected in circuit with said electromagnet for energizing said electromagnet to operate said valve to open position, means under control of the pressure of the fuel and operating upon opening of said valve tolreduce the energy of said electromagnet to an amount just suiilcient to hold said valve in open position but insuiilcient to open the valve.

3. In combination, a thermoelectrically operated valve for controlling the supply of fuel for a burner, an electromagnet for said valve, a thermoelectric generator adapted to be heated by a pilot flame and connected in circuit with said electromagnet for energizing said electromagnet to operate said valve to open position, resistor means for increasing the resistance of the circuit between the thermoelectric generator `and the electromagnet, and means responsive to the opening of said valve for completing` the circuit between said thermoelectric generator and said electromagnet through said resistor means to energize said electromagnet sufliciently to hold said valve open but insuiliciently to" open said valve, said last means being responsive to the pressure of fuel admitted to said valve for completing the circuit between said thermoelectric generator and said electromagnet around said resistor means prior to opening said valve to energize said electromagnet suiciently to open the valve.

4. In apparatus of the class described, in combination, a thermoelectric generator, a circuit connected to said thermoelectric generator and including an electromagnet, a uid iiow controlling member having a rst position shutting off uid iiow and adapted to be moved by energization of said electromagnet by said thermoelectric generator to a. second position permitting fluid ow, means rendered operative upon movement of said ow controlling member to said second position for reducing the energy of said electromagnet in such amount that the electromagnet is capable of holding said ilow controlling member in said second position but is incapable of moving said member to such position, said last means comprising a switch in said circuit, and a resistor in parallel with said switch, said switch being actuated from one position to another position by the pressure of the iiuid controlled by said iiuid flow` controlling member.

` 5. In apparatus of the class described, in combination, a constantly burning piloty burner, a burner remote from said constantly burning pilot burner, a burner-igniting pilot burner for igniting said burner, intermediate pilot burner means for assuring ignition of said burner-igniting pilot burner from said constantly burning pilot burner, a fuel supply line for supplying fuel to said burner and said pilot burners, a gas cock in said fuel supply line, a control valve in said fuel supply line on the outlet side of said gas cock, means for actuating said control valve to open position and for holding it open, and means rendered operable b`y the opening of said gas cock to establish a flow of fuel to said intermediate pilot burner means and to said burner and to extinguish said intermediate burner pilot means and reduce the energy of the means for holding said control valve in open position upon establishment of a ilow of fuel to said burner.

6. Apparatus according to claim wherein the means for actuating the control valve tov open position and holding it open `comprises an electromagnet connected in circuit with a thermoelectric generator and wherein the means for reducing the power of said electromagnet comprises aswitch in said circuit and a resistor connected in parallel with said switch.

7. In a device of the class described, in combination, a main burner, an intermediate pilot burner, a valve body having an inlet, an outlet for supplying fuel to said main burner, a main valve member, and an outlet for supplying fuel 5 to said intermediate pilot burner, a pair of diaphragms responsive to the pressure on the inlet side of said main valve member, a second valve member responsive to one of said diaphragms for opening the outlet for the intermediate pilot burner, and means responsive to the movement of said other diaphragm for opening and holding open said main valve member f or the supply of fuel to the main burner and for reducing the energy of said holding means upon opening of said main valve member.

8. Apparatus according to claim 7 wherein the means for opening and holding open said main valve comprises an electromagnet connected in circuit with a thermoelectric generator and wherein the means for reducing the energy of the holding means comprises a switch insaid circuit and a resistor connected in parallel with said switch.

9. Apparatus according to claim 7 wherein the diaphragms for the pilot and main valves are responsive to the pressure on the outlet side of said main valve upon opening of said valve.

10. In a device of the class described, in combination, a, main burner, an intermediate pilot burner, a valve body having an inlet, an outlet for supplying fuel to said main burner, a main valve member, and an outlet for supplying fuel to said intermediate pilot burner, an electromagnet connected in circuit with a thermoelectric generator for opening said main valve' member and holding it open, a pair of diaphragms responsive to pressureon the inlet side of said main valve member, a second valve member respon- 40 sive to movement of one of said diaphragmsfor opening the outlet for the intermediate pilot burner, a resistor, and means responsive to the movement of the other diaphragm for placing said resistor in circuit in series with said electromagnet and thermoelectric generator upon opening of said main valve member.

l1. Apparatus according to claim 10 wherein said last means comprises a switch connected in parallel with the resistor and actuated by said other diaphragm.

12. Apparatus according to claim 10 wherein said last means comprises a switch connected in parallel with the resistor and actuated by said other diaphragm, and wherein both said diaphragms are responsive to the pressure on the outlet side of said main valve member upon opening of said main valve member for movement of said second pilot burner valve to closed position and said switch to open position.

30 13. In apparatus of the class described, in

combination, a constantly burning pilot burner, a

burner remote from said constantly burning pilot burner, a burner-igniting pilot burner for igniting said burner, intermediate pilot burner means for 05 assuring ignition of said burner-igniting pilot burner from said constantly burning pilot burner, av fuel supply line for supplying fuel to said burner and said pilot burners, shut-off `means in said fuel supply line, a control valve in said fuel supply line on the outlet side of said shutoil means, means for actuating said control valve to open position and for holding it open, and means rendered operable by the opening of said shut-olf means to establish a iiow of fuel to said u intermediate pilot burner means and to said upon establishment of a iiow of fuel to said burner. 14. In' combination, a thermoelectrically operated valve for controlling the supply of fuel for a burner, an electromagnet for said valve, a. thermoelectric generator. adapted to be heated by a pilot flame and connected in circuit with said electromagnet for energizing said electromagnet to operate said valve to open position, resistor means for increasing the resistance of the circuit between the thermoelectric generator and the electromagnet, and means responsive to the pressure of fuel admitted to said valve for completing the circuit between said thermoelectric generator and said electromagnet around said resistor means prior to opening said valve to energize said electromagnet sumciently to open the valve.

. RUSSELL MATTHEWS.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,142,852 Simon June 15, 1915 2,084,654 Ray June 22, 1937 2,098,192 Matthews Nov. 2, 1937 2,195,650 Hardy Apr. 5, 1940 2,366,774 Eskin et al Jan. 9, 1945 2,368,850 Lange Feb. 6, 1945 2,383,676 Paille Aug. 28, 1945 2,384,696 Ray Sept. 14, 1945 2,385,530 Paille Sept. 25, 1945 2,398,215 Eskin Apr. 9, 1946 2,403,412 Strobel et al. July 2, 1946

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