US2699821A

US2699821A - Single point ignition

Info

Publication number: US2699821A
Authority: US
Inventors: Witzel Ernst
Original assignee: Milwaukee Gas Specialty Co
Current assignee: Milwaukee Gas Specialty Co
Priority date: 1947-03-31
Filing date: 1947-03-31
Publication date: 1955-01-18
Anticipated expiration: 1972-01-18

Description

Jan. 18, 1955 Filed larch 51. 1947 E. WITZEL SINGLE POINT IGNIT-ION 4 Sheets-Sheet. l

Jan. 18, 1955 Filed March 31, 1947 E. WITZEL. 2,699,821 SINGLE POINT IGNITION 4 Sheets-Sheet 2 j W Z 9 5 Jan. 18, 1955 wrrz L 2,699,821

SINGLE POINT IGNITION I Filed March 31, 1947 i 4' Sheets-Sheet '3 1955 E. WITZEL 2,699,821,

SINGLE POINT IGNITION.

Filed March 31, 1947 4 Sheets-Sheet 41 United States Patent SINGLE POINT IGNITION Ernst Witzel, Milwaukee, Wis., assignor to Milwaukee Gas Specialty Company, Milwaukee, Wis., a corporation of Wisconsin Application March 31, 1947, Serial No. 738,412

12 Claims. (Cl. 158-124) 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 embodiments of the invention which I shall describe hereinafter in connection with the drawings are single point ignition systems 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 burner 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 provision of separate constantly burning pilot burners, one for the top burners and another or others for the baking oven, broiler or other burners, increases the amount of gas which is used and results in unnecessary heating of the appliance and the room in which the appliance is located.

The stooping and hazards of lighting an oven burner or the like with a match are well known in the art. In order to ignite an oven burner (broiler or baking oven) or like burner from the top pilot burner, a system of socalled flash tubes is often employed. Unburned gas may rise in these tubes and ignite at the top pilot burner, the flame then flashing back or receding to the oven pilot burner.

in case the flash tube is disposed vertically, with the oven pilot burner located directly at the lower end of this tube, trouble is experienced in ignition when the gas cock is closed for a short time interval and immediately opened again. This is undoubtedly due to the fact that the air in the flash tube is kept at high temperature by the oven pilot burner and thus does not permit the then heavier-than-air gas to rise in this tube.

One of the main objects of the present invention is to provide a simple, improved and eifective single point igniter which will avoid the trouble which has heretofore been experienced where the flash tube is disposed vertically with the oven or other remote pilot burner located directly at the lower end of this tube.

Another and more specific object of the invention is to provide, in conjunction withthe constantly burning top pilot burner and an oven pilot burner for the oven or other remote burner, an intermediate pilot burner installed at the vertical section or directly at the lower end of the flash tube and linked to the system in such manner that it will be extinguished after a certain time interval so that the flash tube maycool and be in operating condition for any succeeding ignition.

Another object of the invention is to provide means for automatically shutting off the main gas supply to the oven or like burner in case the oven pilot burner should fail to ignite or to maintain the oven pilot flame.

Another object of the invention is to provide a thermofor preventing admission of gas to the oven or like burner except when the oven or like pilot burner is ignited, thus providing so that no gas be admitted to the oven burner without assurance that the oven pilot burner is ignited.

Another object of the invention is to provide, for a 2,699,821 Patented Jan. 18, 1955 2 system of the class described, a thermoelectric control device operable to shut off or prevent the supply of fuel to the oven pilot burner and to the intermediate pilot burner and oven burner in case the oven or like pilot is extinguished.

Another object of the invention is to provide a thermoelectric control device having a reset button which may be depressed before or while the gas cock is being opened to close the fuel supply passage to the oven burner and open ports leading to the intermediate and oven pilot burners, thus assuring ignition of the intermediate and oven pilot burners before the fuel supply passage to the oven burner is opened.

Another object of the invention is to provide a thermoelectric control device enabling a time delay to permit a thermocouple subject to the heat of the oven pilot burner to energize an electromagnet connected in circuit therewith suiiiciently to hold the main thermoelectric control valve open for the supply of fuel to the oven burner and the oven pilot burner when the reset button is released.

Another object of the invention is to provide a thermoelectric control device enabling a time delay at the very start of the operation during which the reset button may be depressed to shut off the supply of fuel to the oven burner and establish a supply of fuel to the intermediate and oven pilot burners.

Another object of the invention is to provide a thermoelectric control device in which the thermocouple heated by the oven pilot burner is adapted to energize its connected electromagnet sufficiently during the time delay to hold the main thermoelectric valve open so that, upon release of the reset stem, gas passes to the oven burner and oven pilot burner and the gas supply is shut off to the intermediate pilot burner.

Another object of the invention is to provide improved latch means for holding the reset stem in depressed position and improved release mechanisms for the reset stem.

Another object of the invention is to provide a single point ignition system and instrumentalities 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 eifectiveness in use.

Further objects and advantages of the invention will appear from the following detailed description, taken in connection with the accompanying drawings which illustrate the manner of constructing and operating certain embodiments of the invention.

In the drawings:

Figures 1 and 1A are parts of a diagrammatic view which, when placed with Figure 1A to the rightof Figure 1 and the line BB of Figure 1A on the line AA of Figure 1, form a complete diagrammatic view of one form of single point ignition system embodying the present invention; and

Figures 2 and 2A are parts of a diagrammatic view which, when placed with Figure 2A to the right of Figure 2 and the line D-D of Figure 2A on the line CC of Figure 2 form a complete diagrammatic view of another form of single point ignition system embodying the present invention.

A fuel supply pipe 3 leads to the burner 1 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 flow 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 or like burner 1 is provided with an oven or like pilot burner 7 for igniting it. A flash tube 8 opens at its upper end directly beneath the flame 9 of the con stantly burning pilot burner 2. This tube extends vertically downwardly from the pilot burner 2 and, at its lower end, has, for example, a flared mouth 10 directly above the flame 11 of an intermediate pilot burner 12. The in termediate pilot burner 12 is spaced laterally from the oven pilot burner 7, and the tube 8 has a branch tube 13 extending laterally therefrom and opening at its outer end directly above the flame 14 of the oven pilot burner. The branch tube 13 is shown extending practically horizontally from the pilot burner 7 to the tube 8.

The thermoelectric control valve comprises a valve body 15 having an inlet16 and an outlet 17. Contiguous sections of the fuel supply pipe 3 are connected to the inlet 16 and outlet 17, for example, by screwing them into the inlet and outlet which are shown as internally threaded. Internally the valve body 15 has a partition 18 provided with a port 19 for placing the inlet chamber 20 in communication with outlet chamber 21.

Valve seats

22 and 23 are provided on the partition 18; one valve seat surrounding one end of the port 19 for cooperation with the main thermoelectric shutoff valve 24, and the other valve seat surrounding the other end of the port 19 for cooperation with a flow interrupter valve 25.

The valve 24 is fixed, for example, by a pin 26 upon the inner end of the valve stem 27 preferably for some relative movement thereon so as to have self-accommodating seating engagement with the cooperating valve seat 23. The valve 24 is preferably provided with a valve gasket or yielding valve facing suitably secured in place and adapted to engage the valve seat 23 when the safety shut-off valve is closed. The pilot burner 2 is supplied with fuel by a pipe 29 leading, for example, from the fuel supply pipe 3 anterior of the gas cock 6.

The thermoelectric safety shutoff valve 5 is, in general, of the type shown in the prior patents of Clarence Wantz, Nos. 2,367,870 and 2,307,871, patented January 12, 1943. The valve stem 27 extends outwardly for reciprocatory movement through an opening in the inner end of an electromagnet and armature housing 30. The armature 31 is secured to the outer end of the valve stem 27 preferably sufriciently loosely to permit self-accommodation of the armature to the pole ends of the magnet frame 32. The stem 27 is disposed generally concentrically of the housing 30, and the armature and magnet are disposed within this housing. The housing 36 fits telescopically in the valve body 15. Packing 33, around the valve stem 27, is interposed between a spring seating member 34 and the inner end of the housing 30. A coiled compression spring 35 for seating the valve 24 against its seat 23 is interposed between the valve 24 and the spring seat ing member 34.

The magnet frame 32 is secured to a terminal bushing 36. The shank of the bushing 36 extends, for example, through an opening in a sleeve 37 screwed into the valve body 15, and is externally threaded for threaded engagement with a nut 38 by means of which the bushing 36 is clamped to the sleeve 37. Sealing gaskets are provided at 39 and 40. The outer end of the housing 30 is peened, for example, at 41, over the flanged or headed outer end of the bushing 36.

In the illustrated embodiment of the invention a thermocouple, indicated at 42, is positioned so that the hot junction 43 thereof will be heated by the oven pilot flame 44 as long as the oven pilot is burning. The thermocouple and leads therefor selected for illustration may be similar to the thermocouple and leads more fully disclosed in Oscar I. Leins Patent No. 2,126,5 64, patented August 9, 1938, or thethermocouple or thermoelectric generator and leads may be of any other suitable or preferred form.

For the purpose of the present description, suffice it to state that the particular thermocouple selected for illustration comprises an outer tubular metallic thermocouple element and an inner metallic thermocouple element of different thermoelectric characteristics. The inner thermocouple element is joined at one end to the outer end of the outer thermocouple element to form the thermojunction 43 which is placed in position to be heated by the oven pilot burner 7. An inner lead conductor 45 is joined to the inner thermocouple element to form an internal thermojunction, and an outer tubular lead eonductor 46 surrounds the inner lead conductor and is connected to, the outer thermocouple element, for example through a sleeve 47, to form a third thermojunction. The inner lead conductor is insulated from the outer lead conductor, for example, by a Wrapping of insulation on the inner lead conductor.

A quick detachable or removable connection is preferably provided between the electromagnet of the safety shutoff device and the ends of the

leads

45 and 46 opposite the ends which are connected to the thermocouple elements. To this end the terminal tip 48 has a conical depression in its outer end, and a connector or terminal cone (not shown) on the end of the conductor 45 is adapted to be detachably clamped in contact therewith by a sleeve (not shown) threaded into the outer end of the bushing 36. The adjacent end of the outer tubular lead conductor 46 is connected in circuit with one side of the coil 50 which surrounds the legs of the magnet frame, for example through the bushing 36. The other side of the coil 50 is connected in circuit with the inner lead conductor 45 through the terminal tip 48. The use of other forms of thermocouples or thermopiles is, of course, contemplated within the scope of the present invention.

A cap nut is screwed into the opposite end of the valve body 15 in axial alignment with the magnet housing 30. This cap has, at its inner end, a bore 56 opening through a passage 57 into a tube 58 which is connected to the intermediate pilot burner 12 for the purpose of supplying fuel thereto, as will hereinafter appear. At its outer end the cap nut 55 has a bore 59 in which a reset button 60 is mounted for reciprocatory movement. The button 60 is aligned axially with the valve stem 27 and has fixed thereto a reset stem 61. The reset stem 61 is guided at 62 in the cap nut 55 and extends inwardly' through the bore 56 with annular space between it and the inner periphery of the bore.

The inner end of the stem 61 extends inwardly from the cap nut 55 and into the valve body 15, and is headed at its inner end. The inner end of the bore 56 is closed and sealed by closure and packing or sealing means 62 held in place by retainer means 63. The inner end of the stem 61 has an axial bore 64 closed at the inner end of the stem, for'example, by a plug 65. A laterally opening port 66 is adapted to admit gas or other fuel into the bore 64, and a-laterally opening port 67 is adapted for delivering this fuel into the bore 56 and thereby to the fuel supply line leading to the intermediate pilot burner 12.

The reset stem 61 has reciprocatory movement through an axial opening in the how interrupter valve 25. A coiled compression spring 71, interposed between the valve 25 and the inner end of the cap nut 55, seats the valve 25 on its seat 22 to shut off the delivery of fuel to the oven burner 1 through the outlet 17 when the reset stem 61 is depressed inwardly. The valve 25 is preferably provided with a valve gasket or yielding valve facing suitably secured in place and adapted to engage the valve seat 22 when the valve 25 is closed.

A port or passage 72 leads laterally from the port 19 for the delivery of fuel to the oven pilot burner 7 through fuel supply line 73 whenever the valve 24 and gas cock 6'are open.

The outer end of the bore in which the stem 61 is guided at 62 is sealed against leakage of gas by suitable packing 75. A washer is provided at 76, and surrounding the stem 61 and interposed between the washer 76 and the reset button 60 is a coiled spring '77 which acts to move the reset button 60 and stem 61 to their outwardly projected positions, as will presently appear.

An annular raised lip 78 on the headed inner end of the stem 61 is adapted in the movement of the reset stem to its outwardly projected position to engage the yielding facing of the valve 25 and move this valve to open position away from its seat 22 against the action of the spring 71.

A snap ring 80, mounted for movement in a lateral direction in an opening 81 in the cap 55, has a detent 82 which is adapted to engage in a notch 3 in the periphery of the reset stem 60 to hold the reset stem in depressed or inwardly projected position. In this position of the reset stem the valve 25 is closed by the spring 71 and the port 66 is positioned outwardly of the valve 25 for delivery of gas to the intermediate pilot burner 12.

A screw 84 is screwed into the cap 55 in register with the ring 80. A plunger 85, pressed inwardly by a spring 86 confined between it and an adjusting screw 87 screwed into the screw 84, has engagement at its inner end with the ring and tends to yieldingly urge the ring 80 to the position shown in Figure l.

The form of the means for releasing the snap ring 80, and thereby the reset stem 61, may vary widely. The particular release means shown in Figures 1 and 1A comprises a bi-metallie or other suitable temperature responslve element 88 mounted, for example, in the enlarged outer end 89 of a tubular member 90 which is screwed at its opposite end into the cap 55 in register with the snap ring 80 and diametrically opposite the plunger 85. A flexible rod 91 is positioned within the tubular member 90, with one end engaging or adapted to cooperate with the temperature responsive element 88, and the opposite end engaging or adapted to cooperate with the snap ring 80. The temperature responsive element 88 is positioned in juxtaposition to the intermediate pilot burner 12 and is subject to the heat of the flame 92 of this pilot burner. A cap nut 93 is screwed in the outer end of the cap 55.

To start the operation of the system shown in Figures 1 and 1A the following sequence is followed:

The reset button 60 is depressed to the position shown in Figure 1 before or while the gas cock 6 is being opened. This results in closing of the valve 25 to shut off the supply of fuel to the oven burner 1 and opening of the port 66 and port 72 for the supply of fuel to the intermediate and oven pilot burners 12 and 7.

The unburned gas from the intermediate and oven pilot burners 12 and 7 rises in the tube 8, which is alwaysrelatively cool to permit this action. As it reaches the flame 9 of the constantly burning pilot burner 2, the gas is ignited and then recedes or flashes back to light the intermediate and oven pilot burners 12 and 7.

The temperature responsive element 88 is now slowly heated and, after a given time interval, the bi-metallic element snaps into the dotted line position (Figure 1), thereby pushing the flexible rod 91 against the snap ring 80 which is thus released from the reset button 60. The reset stem then moves outwardly under the action of the spring 77. The edge or lip 78 on the inner end of the reset stern engages the valve 25 and moves it to open position. The contacting of the edge 78 with the valve 25 shuts off the flow of fuel to the intermediate pilot burner 12 so that this pilot burner may immediately cool and thereby be in readiness for a succeeding operation, even where such operation follows immediately. With the valve 25 open, gas passes through the outlet 17 to the oven burner 1, which is ignited by the oven pilot burner 7 which continuesto be supplied with gas through the port 72.

During the time delay at thevery start of the operation, the reset stem is depressed, closing the valve 25 to the oven burner but opening the valve 24 by cooperation therewith (as shown in Figure 1), which also moves the armature 31 into contact with the magnet frame 32. At this time the

ports

66 and 72 are open for the supply of fuel to the intermediate and oven pilot burners 12 and 7. The delay is timed so that the thermocouple 42 will be heated sufliciently to retain the valve 24 in open position by energization of the electromagnet.

If the oven pilot burner 7 should fail to ignite or to maintain the pilot flame, the thermocouple 42 will not be heated sufiiciently to hold the valve 24 open, and this valve will operate to closed position to shut off the main gas supply to the oven burner; also the gas supply to the oven pilot burner 7 and intermediate pilot burner 12. In case the constantly burning pilot burner is extinguished, the pilot burners 12 and 7 cannot, of course, be ignited therefrom, and if it is extinguished while the oven pilot burner is burning and the oven pilot burner is later extinguished, the system canot be again placed in operation until the constantly burning pilot burner is relighted.

In the embodiment of the invention shown in Figures 2 and 2A, parts which are similar to those previously described are designated by primed reference characters corresponding with the reference characters used in Figures l and 1A.

The system of Figures 2 and 2A employs an all electric release instead of the temperature responsive release element of the preceding embodiment of the invention. The electric release comprises a thermoelectric generator such, for example, as a thermocouple 100 subject to the heat of the flame 101 of the constantly burning top pilot burner 2'. The thermocouple 100 is connected in circuit with the coil of an electromagnet (not shown), for example in the manner described in connection with the thermocouple 42 of the preceding embodiment of the invention. A housing 102 houses the releasing electro magnet and, in turn, fits telescopically in a tubular body 103 fastened at 104 to the cap 55 in appropriate register with the snap ring 80'.

One side of the coil of the electromagnet within the 6 housing 102 is connected by a conductor 105 with one of the elements of the thermocouple 100. The other side of the coil is connected by a conductor 106 to the pivoted end of an armature 107 which is pivoted at 108. The other element of the thermocouple 100 is connected by a conductor 109 to a contact 110 at the relay or thermocouple actuated switch 111. The armature 107 may be held in engagement with the contact 110, for example, by a spring 112 to complete the circuit which includes the thermocouple 100 and its connected electromagnet.

A third thermoelectric generator, which may, for example, be in the form of a thermocouple 113 as previously described, is disposed in juxtaposition to the intermediate pilot burner 12' where its hot junction is subjected to the heat of the flame 92 of this pilot burner. The thermocouple 113 is connected in circuit with the coil 114 of an electromagnet 115 at the relay 111. The elecromagnet 115 is positioned so that, when energized, it will move the armature 107 to attracted position and thereby open or disable the circuit for the thermocouple 100, for example, by opening this circuit between the conductors 106 and 109.

A curved lever 116 is pivoted at 117 in an opening 118 in the wall of the tubular body 1034. One end of this lever extends through a notch in the outer end of the reset button 60'. The other end of the lever 116 is disposed within the tubular body 103 and engages in an opening 119 in a release plunger 120. The plunger 120 is connected to the stem 121 of the armature 122. When the circuit for the thermocouple 100 is closed or not disabled, the heat of the flame of the pilot burner 2 on the thermocouple 100 energizes the electromagnet 123 sufliciently to hold the armature 102 in attracted position and the plunger 120 out of releasing position. When the circuit for the thermocouple 100' is open or disabled by the heat of the flame 92 of the intermediate pilot burner 12 on the thermocouple 113, a spring 124 moves the armature 122 to projected position and the plunger 120 against the snap ring 80'. The snap ring 80' is thus released from engagement with the reset button 60 at 125, and the reset stem 61 moves outwardly under the action of the spring 77 in the manner of the preceding embodiment of the invention.

The plunger 85', for actuating the snap or latch ring 80 to latching position when the reset button 60 is depressed, and the mounting for the plunger 85 are similar to the plunger 85 of the preceding embodiment of the invention and its mounting.

The operation of the single point ignition system of Figures 2 and 2A, including constantly burning top-pilot burner 2', oven burner 1', oven pilot burner 7', intermediate pilot burner 12, flash tube 8, 13', gas cock 6 and thermoelectric control device 5 are substantially as described in connection with the preceding embodiment of the invention, and therefore the description in these respects will not be repeated.

The operation of the reset stem latch and release mechanism shown in Figures 2 and 2A is as follows:

in conjunction with, or before opening, the valve 6, the lever 116 is depressed and moves the reset stem 61 to depressed'position, closing valve 25' and opening ports 72' and 66 for delivery of fuel to the oven pilot burner 7' and intermediate pilot burner 12. In depressing the stem 61' the snap ring 80 operates to lock this stem depressed and to provide a time delay permitting the electromagnet 32, 50' to be energized sufliciently by the heat of the oven pilot burner on the thermocouple 42 to hold the armature 31 in attracted position and. the valve 24' open. The depression of lever 116 also moves the armature 122 to attracted position, and since the thermocouple 100, for energizing the electromagnet 123 is subject to the heat of the constantly burning pilot burner 2', the electromagnet 123 is always energized and the lever 116 is thus held in depressed position by the ring 80.

With the depression of the reset stem 61, the admission of gas to the intermediate pilot burner 12 results in ignitlon of this pilot burner in the manner previously de scribed. The pilot burner 12 heats the hot junction of the thermocouple 113 which, in turn, energizes the electromagnet 115 of the relay 111. After a predetermined time which may be varied or determined in advance, as 111 the preceding embodiment of the invention, the electromagnet 115 gains sufiicient power to attract armature 107 and thus interrupts the current to the electromagnet or power unit 123. This releases the armature 122, and the spring 124 moves the release plunger 120. against the snap ring 80. Thesnap ring 80 is thus released from engagement with the reset button 60. at 125, and the reset stem 61' moves outwardly under the action of the spring 77 in the manner and with the results described in connection with the preceding embodiment of the invention.

The invention is not limited to the use of one intermediate pilot burner, but contemplates the use of a plurality of intermediate pilot burners variously arranged. The invention also contemplates actuation of the release mechanism otherwise than by the heat of the intermediate

pilot burner shown'at

12 and 12 respectively in Figures 1A andZA.

Many other combinations are contemplated within the scope of the present invention. Therefore the embodiments of the invention shown in the drawings are for illustrative purposes only, and it is to be expressly under-. stood 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 a device of the class described, in combination, a valve body, a partition in said valve body having a port opening therethrough, valve seats on said partition at opposite ends of said port, an inlet on one side of said partition, an outlet for delivery of gas to a main burner on the opposite side of said partition, port means opening from the valvebody between said valve seats for delivering fuel to a pilot burner in juxtaposition to the main burner, valve members movable into and out of cooperation with the respective valve seats, means individual to each of said valve members normally biasing them to closed position, a reset stem having a normally retractive position and movable therefrom for resetting the valve member cooperable with the valve seat on the inlet side of said partition to open position, said reset stem having movement through the other valve member and having a ported passage therein for establishing a supply of fuel to another pilot burner when said other valve member is closed and said reset stem is in resetting position, latch means for latching said reset stem in resetting position, means for releasing said latch means after a time delay following commencement of the resetting operation and means operable to return said reset stem to its retracted position upon release thereof by said latch means.

2. In a device of the class described, in combination, a valve body, a partition in said valve body having a port opening therethrough, valve seats on said partition at opposite ends of said port, an inlet on one side of said partition, an outlet for delivery of gas to a main burner on the opposite side of said partition, port means opening from the valve body between said valve seats for delivering fuel to a pilot burner in juxtaposition to the main burner, valve members movable into and out of coopera tion with the respective valve seats, means individual to each of said valve members normally biasing them to closed position, a reset stem having a normally retractive position and movable therefrom for resetting the valve member cooperable with the valve seat on the inlet side of said partition to open position, said reset stem having movement through the other valve member and having a ported passage therein for establishing a supply of fuel to another pilot burner when said other valve member is closed and said reset stem is in resetting position, latch means for latching said reset stern in resetting position, means for releasing said latch means after a time delay following commencement of the resetting operation, said latch releasing means comprising a heat responsive element, and means operable to return said reset stem to its retracted position upon release thereof by said latch means.

3. Control means comprising, in combination, a valve body having a main fuel inlet and a main fuel outlet, said valve body having first and second pilot fuel outlets, a first valve member having closed position shutting off the fuel supply through said main fuel outlet and both said pilot fuel outlets, second valve means having closed position shutting off only the fuel supply through said main fuel outlet while permitting fuel supply through said pilot fuel outlets when said first valve member is open, means individual to said first valve member and to said second valve means for biasing them to-closed position, reset meansfor resetting said second valve means to position shutting off the fuel supply through said main fuel outlet and said firstvalve member to open position and operable by such resetting movement to open the first pilot fuel outlet, the second pilot fuel outlet being open whenever said first valve member is open, and closed when said first valve member is closed, latch means for latching said first valve member in open position with said second valve member in closed position and said first pilot fuel outlet open, heat responsive latch releasing means for releasing said latch means, and means operable upon release of said latch means to move said second valve member to open position and to close said first pilot fuel outlet.

4. Control means according to claim 3 wherein there is heat responsive means for holding said first valve member in open position and wherein there is a time delay in the action of the heat responsive latch releasing means sufii-. cient to permit the heat responsive holding means to become effective. to hold said first valve member in open position before said latch means is released.

5. Control means according to claim 3 wherein there is an electromagnet connected in circuit with a thermoelectric generator for holding said first valve member in open position, and wherein there is a time delay in the action of the heat responsive latch releasing means suflicient to permit energization of said electromagnet by said thermoelectric generator in amount to hold said first valve member open.

6. Control means according to claim 3 wherein there is an electromagnet connected in circuit with a thermoelectric generator for holding said first valve member in open position, and wherein the heat responsive latch releasing means comprises a bimetallic element having a delayed action timed so that said electromagnet will be energized sufiiciently by said thermoelectric generator to hold said first valve member open before the latch means is released.

7. Control means according to claim 3 wherein there is heat responsive means for holding said first valve member in open position, and wherein the heat responsive latch releasing means is held again'st latch releasing action by an electromagnet connected in circuit with a thermoelectric generator; there being heat responsive means for disabling said thermoelectric generator circuit to release said latch releasing means for latch releasing action.

8. Control means according to claim 3 wherein the reset means comprises a reset stem having reciprocatory movement through said second valve member.

9. Control means according to claim 3 wherein the reset means comprises a reset stem having reciprocatory movement through said second valve member, and wherein said reset stern has a ported passageway constituting said first pilot fuel outlet.

10. Control means according to claim 3 wherein the valve body has an internal partition provided with a port having valve seats at its opposite ends, one for cooperation with said first valve member and the other for cooperation with said second valve member.

ll. Control means according to claim 3' in combination with a main burner, an igniting pilot burner, and intermediate pilot burner and a constantly burning pilot burner, wherein the main fuel outlet supplies fuel for the main burner, the second pilot fuel outlet supplies fuel for the igniting pilot burner in juxtaposition to the main burner, and the first pilot fuel outlet supplies fuel for theinte'rmediate pilot burner between the constantly burning pilot burner and said igniting pilot burner.

12. In a device of the class described, in combination, a valve member, an electromagnet, an armature for said electromagnet which, when attracted, holds said valve member in a given position, reset means for moving said armature to attracted position and said valve member to said given position, latch means for engagement with said reset means to latch the latter in resetting position, said latch means being biased to latching position, and latch releasing means acting upon said latch means against the bias of the latter for movement thereof out of engagement with said reset means to release said reset means from resetting position after a time delay following movement of said reset means to resetting position, said latch releasing means being movable to latch releasing position by thermally responsive means and being free of the latching action of said latch means in the latching position thereof.

(References on following page) References Cited in the file of this patent UNITED STATES PATENTS Castonguay Aug. 28. 1934 Jones et a1. Aug. 4, 1936 Wild Oct. 6, 1936 East et a1. Dec. 8, 1936 Geurink et a1. Feb. 23, 1937 Gauger Mar. 2, 1937 10 Hollman July 20, 1937 Matthews Nov. 2, 1937 Wunsch et a1. Oct. 7, 1941 Paille Oct. 20, 1942 Paille Mar. 13, 1945 Strobel Dec. 25, 1945 Caparone June 22, 1948 Matthews Dec. 11, 1951