US2361945A - Safety control for gaseous fuel burners - Google Patents

Description

NOV. 7, 1 944. w JACKSON 2,361,945

SAFETY CONTROL FOR GASEOUS FUEL BURNERS Filed May 14, 1941 3 sheets-sheet 2 INVENTOR. WILBUR JAc/mu.

NOV. 7, 1944. w c s o 2,361,945

SAFETY CONTROL FOR GASEOUS FUEL BURNERS Filed May 14 194]. 3 Sheets-Sheet 3 INVENTOR.

WIL BUR E JACKSON.

BY ,W/Mm

ATTORNEY.

Patented Nov. 7, 1944 SAFETY CONTROL FOR GASEOUS FUEL BURNERS Wilbur F. Jackson, Lynwood, CaliL, assignor to Grayson Heat Control, Ltd., Lynwood, Call!" a corporation of California Application May 14, 1941, Serial No. 393,398

8 Claims.

This invention relates 'to safety controls for gaseous fuel burners and more particularly to controls for domestic water heaters and th like.

Fuel controlling devices have been proposed to permit manual opening of the pilot burner fuel passage and automatic opening of the main burner line only after the pilot burner is lighted. In normal operation the fuel supply to the main burner is thermostatically regulated to maintain the water to be heated at a predetermined temperature. Should the flame of the pilot burner be extinguished for any reason, the fuel supply to both the main and pilot burners is shut off, and no fuel can flow through either burner until the device as been manually reset and the pilot burner relighted.

During the resetting operation it is highly important that the flow of fuel to the main burner be positively prevented. It will be apparent that ii the valve or other control device is operated to permit fuel to be supplied. otherwise than to the pilot burner when the resetting device is operated, such fuel may escape and collect unburned at the risk of a possible explosion when the pilot flame is lighted. Devices for this purpose have included interlock means between the main fuel valve and the resetting device to prevent movement of the latter except in certain positions of the former. Other devices utilize dual valves and are generally more complicated than is desirable.

It is an object of this invention automatically to prevent fuel from flowing to the main burner whenever the safety control is being reset until after the pilot burner is relighted.

Another object of the invention is to provide adequate safety means in the control device while reducing the number of parts required.

Another object of the invention is to ensure positive operation of the safety control when required.

Another object of the invention is to combine shut-oil, safety and thermostatic regulating devices into a simple, compact and reliable structure, permitting economy in manufacture and facilitating installation and repair.

Other objects and advantages will become apparent from the following description taken in connection with the accompanying drawings, wherein:

Fig. 1 is a plan view of the improved control;

Fig. 2 is a side elevation;

Fig. 3 is an end elevation;

Fig. 4 is a longitudinal sectional view;

Fig. 5 is a section taken on the line 5--5 01' Fig.

4 looking in the direction indicated by the arrows;

Fig. 6 is an enlarged section taken on the line 6-8 of Fig. 3 looking in the direction indicated by the arrows;

Figs. 7, 8 and 9 are partial sections taken along the line 1-1 of Fig. 4 and showing different positions of the shut-off valve; and

Fig. 10 is a front elevation of a detail.

Referring more particularly to the drawings, the control comprises a casing L5 provided at one end with a laterally extending intake nipple l1 and, at the other end, with an outlet nipple i3 adapted to be connected by suitable piping with the main or heating burner of the water heater or other appliance (not shown).

The upper portion of the casing I5 is shaped to provide a tapered valve seat 2| within which a tapered plug cock 23 is seated. The plugcook 23 is provided with an axial bore 25 with which a port 21, extending through one wall of the cock 23', communicates. The port 21 affords communication between the inlet nipple I1 and the bore 25 in order that the fuel may flow into the body of the casing I! when the cock is in the open I position shown in Fig. 4.

The cock 23 is provided with a reduced stem 29 having a dial 3| mounted thereon against rela-.

tive rotation and by means of which the cock 23 may be rotated in its seat2l. Movement of the cock 23 away from its seat is limited by a retainer plate 33 secured to the casing II by means of the screws 35 and overlying the shoulder 30 formed by the junction of the reduced stem 28 with the cock 23. A spring 31 is housed within a recess 38 at the junction of the stem 29 with the shoulder 30 and, by its engagement with the overlying portion of plate 33, serves to maintain the cock 23 resiliently in its seat 2 i.

Rotation of the cock in its seat is limited to substantially 180 between full-open and fullclosed positions by the provision of an upstanding flange 40 on the plate 33 which enters an arcuate slot 42 formed in the underside of the dial 3!. The stem 29 of the cock is provided with a threaded bore 44 for the reception of an adjustable plug 46 which extends into the bore 25 and serves to regulate the flow of fuel through the port 21.

The shut-off cock, which is constructed as described, is adapted for controlling fuel flow for both the main and pilot burners of the appliance. The pilot control includes an arcuate groove 48 formed in the seating surface of the cock 23 opposite the port 21. .The seat 2| is provided with a similar but shorter arcuate groove 50 communimarked On."

eating at one end with the inlet nipple II. A passage 52 extends from the seat 2I adjacent the other end of the groove 58 and communicates with a passage 54 extending obliquely across the casing I5 and terminating in a horizontal passage 58.

By referring to Figs. 7, 8 and 9, the flow of fuel in various positions of the shut-off cock 23 may be ascertained. In Fig. 7 the cock is shown in closed position and there is no communication between the inlet nipple I1 and the port 21 -or between the arcuate groove 48 and the passage 52. Upon being rotated from the closed position the cock first reaches the pilot position, designated by a notch 88 on the edge of the dial 3i, marked Pilot (Fig. 1)". This position is shown in Fig. 8 and the arcuate groove 48 is now in communication with the passage 52. The next position of the plug cock 23, upon further rotation, is the on" position, suitably designated by the notch 82 in the-edge of the dial 3i, and This position is shown in Fig. 9 and the port 21 in they cook communicates with the inlet nipple I! while, at the same time, communication between the passage 52 and the inlet nipple I1 is afforded by the arcuate groove 48 extending across both the passage 52 and the groove 58 in the valve seat.

In order to facilitate positioning of the dial 3i in the "pilot position a non-positive stop is provided which, as shown in Fig. 3, comprises a plunger 64 mounted within an aperture 68 formed in the underside of the dial 3i and yieldably urged into engagement with a depression 88 in the plate 38 by means of the spring I8. Thus, the on" and ofl positions of the shut-E cock are located by the positive stop and the pilot" position by both an audible click and increased resistance to rotation of the dial afiorded by the device described.

An end casing 58 is secured to the main casing I by means of the screws I2, and a gastight Joint is obtained by the provision of a asket I4 between these members. As shown in Fig. 6, the end casing 58 is provided with an adjustable plug 15 having a hollow threaded end 18 reciprocable in a threaded passageway 88 communicating with the passage 58 in the main casing. The hollow end of the plug 18 communicates with an aperture 82 in the plug body which may be moved into and out of registry with a passage 84 formed in the end casing 58. -As will be apparent, rotation of the threaded plug will increase or diminish the efiective area oi. aperture 82 and adjust the amount of fuel that flows through the passage 88. i

The passage-84 communicates with a chamber 86 within which a pilot control valve 88 is housed. The pilot control valve 88 may be of any suitable form and, in this instance, is shown as being of the poppet type adapted to be moved into and out of engagement with its seat-. 88 against the pressure of a coil spring 82 retained in the chamber 88 by the cap 84. The stem 88 of the pilot nection I88 with a conduit I88 connected. as

shown in Fig. 4, with a pilot burner I I8. In order that leakage of gas from the pilot control valve chamber into the main casing I5 may be prevented, the valve stem 88 is provided with a pro- Jection II2 which engages a cap II4 carried by a diaphragm II8 extending across the end of the sealing chamber I88 and secured in engagement therewith by means of the threaded collar H8. The cap I I4 serves to reinforce the center portion of the diaphragm which receives the pressure of the operating parts.

As shown in Fig. 3, the pilot control valve assembly described is housed within part of the end casing 58 and is positioned to one side of the vertical axis of the main casing I5. That portion of the end casing 58 which is adjacent the vertical axis of the main casing I5 is provided with a chamber I28 (Fig. 4) within which a thermoelectric assembly is adapted to be housed. This assembly includes a horseshoe electromagnet I22 seated on its base. I24 in an end cap I25 secured by screws I21 to the end casing 58 and forming a closure for the opening I28. In order to secure the magnet I22 yieldably in position and prevent distortion thereof, a coil spring I28 is held in position on the magnet base I24 by means of a magnet retainer I38 secured by means of the screws I32 to the end cap I26. A stem I34 extends between the legs of the magnet I22 and through the magnet retainer I38, there being an aperture I35 provided in the magnet base I24 to permit further extension of the stem during operation of the device. The stem carries an armature bar I38, abutting a flange I48 on the stem, and adapted to bridge the poles of the magnet I22 in the usual manner. An armature stem spring I42 extends between the nut I48 and the magnet retainer I38 and serves to urge the armature bar I38 away from the poles of the magnet I22. In order to prevent the spring I42 from unseating the magnet from the end cap I26, the spring I28 may be made considerably stronger than the spring I42.

The arms of the horseshoe electromagnet carry the coils I44 of a wire I46 which is connected by soldering or other suitable means to the head I48 of a terminal screw I58, the opposite end of the wire being secured to the magnet retainer I38. As shown in Fig. 6, the terminal screw I88 extends through the end cap 58 and emerges from the main housing I5 at a point behind the connection for the pilot burner conduit I88. The terminal screw I58 is insulated from the body of the casing by the sleeve I52 and the terminal insulator I54. A terminal sleeve I56 having a threaded end I58 is screwed into the end casing 58 around the insulating sleeve I52. A portion I58 of the insulating sleeve projects beyond the terminal sleeve and the terminal screw I58 projects still further. The projecting parts form terminals providing suitable electrical connection for the two elements, I88 and I82, of a thermocouple, these elements being separated at the terminals by means of the insulating washer I88.

The thermocouple may be supported by a bracket I56 in position to be heated by the pilot burner II8, thereby to establish an electric current to the coils I44 of sufficient strength to energize the magnet I22 and hold the armature bar I38 in contact with the pole faces thereof against the force of the spring I42, provided that the armature bar has been moved into contact with the magnet in a manner which will now be explained.

Formed in the end casing 66 immediately above the chamber I for the thermoelectric assembly and on substantially the same vertical axis, is a smaller chamber I68 within which a reset button I10 is slidably mounted. This reset button carries a reset stem I12 extending through an aperture in the bottom wall of the chamber I68 and with a collar I16 between the stem and its pro- .iection I14. A coil spring I18 acts between the reset button I10 and one side of the end wall of the opening I68 to urge the button outwardly from the opening, this movement being limited by the engagement of the collar I16 with the opposite side of the end wall. Thus the spring will cause return or the button I10 to the position shown in Fig. 4 after it has been manually depressed and released.

This invention is particularly directed toward the provision of but a single valve for providing both thermostatic control of the main burner and safety control of the flow of fuel thereto should the pilot burner become extinguished. Accordingly, the body of the main easing II is of hollow form below the portion carrying the plug cock 23 and is provided with a web I82 within which an annular valve seat member I84 is removably mounted. The annular valve seat I84 carries a hollow boss I86, connected thereto by a perforated flange I86, and within which a hollow valve stem I88 is slidably mounted. A valve member 190 is secured on the valve stem I88 and cooperates with the valve seat I84 to control the flow of fuel through the ports I92 in the valve seat to the outlet nipple I9, with which these ports are aligned. It will be observed that the valve assembly is axially aligned with the thermoelectric assembly with which it is operativeiy associated.

The hollow valve stem I88 contains a spring I94 which serves to urge a plunger I96 into contact with a plug I98 closing the inner end of the hollow valve stem. A reduced end on the plunger I96 projects through the plug I08 and is adapted to engage and be operated by a clicker mechanism comprised of a pair of opposed fulcrum levers 200, fulcrum button 202 and clicker disc 204, all of which are housed within a recess 206 formed in the annular valve seat I84.

Thermostatic means for operating the valve I90 through the clicker disc mechanism is provided and consists of an element of the rod-andtube type. A tube 206 of material having a high coeflicient of expansion is securely mounted at its inner end on the casing I5. The rod 208 of the thermo-responsive unit, which is of material having a low coefilcient of expansion, extends within the tube 206 and is threadedly connected at its outer end with a plug 2I0 anchored in the outer end of the tube 206. The inner end of the rod 208 is recessed for the reception of a ball 2I2 secured in position by means of a cap 2. The cap 2I4 engages a sealing disc 2I6, secured in a recess 2I1 in the casing I! by the valve seat I84, and having its inner portion urged into engagement with a thrust member 2I8 by the cap member 2I4.

As is well known, the differential in the expension of the rod and tube, under the influence of the heat of the water in which the device is mounted, causes the rod to actuate the thrust member 2 I8 to operate the clicker disc 204 which, in turn, operates the fulcrum button 202 and the opposed fulcrum levers 200. The levers 200 strike the plunger I86 which actuates the valve member I80 to open position. it being noted that the spring I04 is not compressed at this time as will be apparent hereinafter. Suitable means for mounting the control in the water heater or other appliance are provided by the elongated boss 220 projecting from the casing around the rod and tube element. The temperature at which the valve I80 will be operated may be adjusted by means of a manually operated lever 222 attached to the rod 208 by means of the set screw 224. The lever carries a pointer 226 for cooperation with indicia 220 on the casing. Movement of the lever in a vertical direction will serve to rotate the rod 208 and screw this rod further in or out of the plug 2I0 to change the expansion differential.

Movement of the valve I90 toward and away from its seat by the thermostatic device is governed by the condition of the thermoelectric mechanism previously described. Such governing action is eiiected by the provision of valve operating mechanism for the thermoelectric assembly which will now be described. The armature stem I34 is provided beyond the armature bar I88 with an extension having a threaded end 280.- Mounted on the end 280 is an abutment member 282 having an annular recess 234 intermediate its ends. The abutment member 232 is also provided with a reduced end 236 which extends toward the valve member I90 and is adapted to be spaced therefrom when the armature bar I80 is in the attracted position shown in Fig. 4.

The threaded extension 280 of the armature stetm also carries a collar 238 slidably mounted within a guide disc 240 which, together with a flexible sealing disc 242 carried on the stem, is securely retained in position across the end of the chamber I20 by means of the threaded collar 244. As will be apparent, the function of the sealing disc 242 is to prevent the entrance of fuel into the magnet chamber I20, while at the same time permitting free movement of the armature bar toward and away from attracted position with the poles of the magnet I22.

Extending between the projecting end I14 of the reset stem and the recess 234 in the abutment member 282 is a pivoted lever 246. As shown in Fig. 5, this lever is pivotally mounted at both ends on a pin 248 carried by spaced lugs 250 on the inner face of the end casing 68. The end of the lever adjacent the reset stem extension I14 is curved to slidably engage with the collar I16 thereof, there being a slot 262 formed inthe lever to permit it to extend around the extension I14 for this purpose. The opposite end of the lever is also slotted to extend around the recessed portion 284 of the abutment 282 and is similarly curved for slidable engagement with the walls of the recess 284. The lever 246 is turther provided on one side with a radially extending arm 264 which is adapted to engage at its outer end with the cap member I.

The projecting end I14 of the reset stem extends beyond the lever 246 and carries an operating arm 266 of the form shown in Fig. 10 and secured rigidly in position between a pair of nuts 268. The operating arm 256 extends substantially parallel with the lever 246 through the hollow casing but is movable relatively thereto. The free end of the arm is perforated to accommodate a thimble 260 through which the extension 286 may loosely project. The thimble is not rigidly mounted on the arm 266 but slidable movement in the perforation is limited in one direction by a washer 262 projecting from one 4 d end or the thimble and by an enlarged head :04

at the other end. The washer 282 is yieldably. w

held against the arm 258 by means of an inner spring 288 extending between the collar-284 and the arm 258. Surrounding this inner spring is.

an outer or valve spring 288 which extends between the valve member I98 and the arm 258 and urges these members apart.

' To operate the control from the off position or the dial, as shown in Fig. 'l, the dial is first and thence to the pilot control valve 88 which,

as stated, is in the closed position. At this time the armature stem spring 2 is thrusting the armature stem I84, armature bar I38 and the abutment 282, together with their associated parts, toward the valve I90. The extension 238 from the abutment 232 is at this time engaged with the valve member, tending to hold it closed, and, as the armature stem spring I42 is stronger that the valve spring 894, the thermostatic control is unable to open the valve I90 when the parts are in this position.

The reset button H is then manually actudied to depress the stem I'l'Z. When the reset button I10 is actuated with the dial at the pilot" position and the thermostatic valve I90 closed, the thimble 280 is moved by the operating arm 858 against the pressure of valve spring 288 until it engages the valve member I90. At this point, however, the collar 8 on the reset stem has not moved into engagement with the curvedend of the lever 248. Further manual actuation of the reset button 510 causes the arm 258 to slide relative to the thimble 280 which is held stationary by the valve member compressing the spring 288. It should be noted that the arm 258 moves without any pivotal or tilting motion in a straight line towards and away from the valve member H8. Shortly after the arm 258 compresses the spring 288, the collar M8 on the reset stem engages the curved end of the lever 248. Further manual actuation of the reset button causes the lever 248 to rotate in a clockwise direction, as

the port 21 of the gas cock into the pole faces thereof against the thrust of the spring I42.

The reset button may now be released. Such movement causes the operating am 258 to travel back along the thimble 280 until it engages the washer 282 when further relative movement is prevented. The arm 258 will, however, continue to move back to its normal position carrying the thimble 280 with it and leaving the original clearance between the thimble and the valve member I90. During this movement of the arm 258 and the thimble back to normal position it will be apparent that the lever 248 remains in pivoted position, being maintained by the recess 234 in such position regardless of the release of the reset button H8. Consequently, the lateral arm 254 continues to hold the pilot control valve 88 in open position while both the extension 298 and the thimble 260 are spaced from the valve I90, leaving it free to operate against the spring 288 in response to the thermostatic mechanism.

To cause gas to flow to the main burner the dial must be moved to the "on" position, as shown in Fig. 4 and Fig. 9. Gas is now permitted to flow from the inlet nipple I! through main body of the casing I5. In this position it will be observed that the groove 48 permits gas to flow to the pilot burner by connecting passage 82 with the inlet IT. The indicator lever 222 may be set to the desired temperature indicated on I90 with a snap action viewed in Fig.4, pivoting upon the pin 248 and moving the armature bar I88 into engagement with the pole faces of the magnet I22. The clockwise movement 01 the lever 248 serves to withdraw the extension 236 attached to the armature stem 4 from contact with the valve I88 as the armature bar I38 reaches attracted position. I

The pilot control valve 88 is moved oir its seat by the engagement of the lateral arm 254 with the cap I'M during manual actuation of the reset button to move the lever 248. Hence, gas travelling-through the passages 52, 54, 58 and 84 from the cock 28 is allowed to flow past the pilot control valve 88 and through the passages I02 and I84 to the pilot burner H0. The pilot burner may then be lighted and the flame size adjusted by operation of the adjusting screw I8. The flame from the pilot burner impinges upon the end of the thermocouple which is connected in series with the coil N4 of the electromagnet I22. In a short time the thermocouple generates sumcient current to energize the magnet and maintain the armature bar I88 in contact with the .under thermostatic operation the casing and the control will then be in complete operation.

As previously described in part the rod 208 Of the thermostatic means will actuate the valve through the clinker mechanism provided. The movement of the plunger I98 which efiects opening of the valve moves the spring I94 bodily without compressing it due to this spring being'strong enough to overcome the spring 288 and the'force resulting from the gas pressure on top of the valve. The spring I84 is provided to permit the fulcrum levers to move when the valve is being held closed by the safety mechanism.

In the event that the pilot burner is extinguished, the thermocouple ceases to generate current causing deenergization of the electromagnet and movement of the armature bar I38 away from the pole faces. Such movement of the armature bar is caused by the spring I42 which urges the abutment 232 toward the valve member I90. If the thermostatic mechanism is operating at this time to hold the valve I90 in open position, movement of the extension 238 of abutment 232 will serve to close it. Such action is due to the spring I42 on the armature stem being stronger than the spring I94 in the valve stem and thus overcoming it to move the valve I to closed position.

During this movement of the abutment 282 toward the right, as viewed in Fig. 4, the lever 248 isrotated on its pivot 248 in a counter-clockwise direction. The laterally extending arm 254 moves away from the cap H4 and the spring 92 moves the. pilot control valve to closed position. Thus, when the pilot burner is extinguished for any reason, the safety mechanism operates to close both the main control valve I and the pilot control valve 88, giving a complete shut-oil.

The operating arm 258 and its associated parts I 2,sa1,94s

the "on" position no gas can flow to the main It will be appreciated that the valve I90 ls operated by the thermostatic mechanism under normal conditions, but this mode of operation is supplanted by that of the thermoelectric control whenever conditions demand. If the thermostatic control is holding the valve I90 off its seat, and the safety mechanism comes into operation, the thermoelectric control overcomes the action of the thermostatic control, causing closure of both the main and pilot valves as described. Thus, the thermoelectric control is, in effect, a governor for the thermostatic control which normally operates the valve controlling fuel flow to the burner.

In controls where two or more valves are used in place of the single valve described and shown herein, the thermostatic valve is usually in constant operation but the safety valve is called upon to function only infrequently.- It is appar- 'ent that unless abnormal conditions arise the safety valve has no occasion to operate. As this safety valve usually remains stationary for long periods of time it becomes incapable of functioning efficiently when called upon to do so. An infrequently operated valve is subject to gumming, due to the drying of lubricants, and also to dirt from the gas being deposited on the seating surfaces. Such condition of the safety valve would not be discovered until the resulting leakage became apparent. In the device described and shown herein, the single valve is in constant operation as a thermostatic valve and, when the thermoelectric safety device becomes operative, it acts upon this valve also.

Closure of this valve by the safety control is readily accomplished dueto the absence of dirt on the seating surfaces and the operative -condition in which the valve has been maintained. It may be noted that the continual opening and closing of such a valve will tend to make it selfcleaning.

The embodiment of the invention herein shown and described is to be regarded as illustrative only, and it is to be understood that various modifications and changes may be made within the scope of the appended claims without departing from the spirit of this invention.

I claim:

1. In a safety control for gaseous fuel burners, the combination of a casing having a passage for supplying fuel to the burner, a valve in the passage for controlling the supply of fuel to the burner, said valve being movable between controlling positicns, electromagnetic means having an armature movable between free and attracted positions coaxially with said valve, said armature being adapted to move said controlling valve to one controlling position when moving from one of said positions, a manually operable reset stem mounted in said casing for movement in a path substantially parallel with said armature and valve, a pivoted lever extending between said reset stem and armature for transmitting movements of one to the other for resetting said armature, and a separate holding member secured to said reset stem for operative engagement with said controlling valve for maintaining said valve in said one. controlling position during the resetting operation.

' 2. In a safety control for gaseous fuel burners, the combination of a casing having a passage for supplying fuel to the burner, a valve in the passage for controlling the supply of fuel to the burner, said valve being adapted for axial movement between open and closed positions, electromagnetic means having an armature movable between free and attracted positions, an abutment on said armature coaxial with said valve and engageable'therewith for movement to said closed position when said armature is in free position,

and means telescopically mounted relatively to said abutment and adapted to be substituted therefor in engagement with said controlling valve for maintaining said closed position during movement of the armature to attracted position.

3. In a safety control for gaseous fuel burners, the combination of a casing having a pas sage for supplying fuel to the burner, a valve in the passage for controlling the supply of fuel to the burner, said valve being adapted for axial, movement between open and closed positions, electromagnetic means having an armature movable between free and attracted positions, an abutment on said armature coaxial with said valve and engageable therewith for movement to said closed position when said armature is in free position, a manually operable reset stem mounted in said casing for axial movement substantially parallel with said abutment and valve, a pivoted lever extending between said reset stem and abutment for transmitting movements of the one to the other for resetting said armature to attracted position, a rigid member secured to said reset stem and extending in proximate relation to said abutment, and means carried by said rigid member for telescopic movement relative to said abutment to be substituted therefor in engagement with said controlling valve for maintaining said closed position during movement of the armature to attracted position.

4. In a combined temperature and safety control for gaseous fuel burners having main and pilot burners, the combination of a casing having passages for supplying fuel to the main and pilot burners, a main control valve intercepting the supply of fuel in said passage to the main burner, a pilot control valve intercepting the supply of fuel in said passage to the pilot burner, said valves being biased to closed position, a thermostat for operating said main control valve, thermoelectric means energizable by a flame at the pilot burner and having an armature movable with respect to said main control valve between released and attracted positions, means carried by said armature for operating said main control valve in opposition to said thermostat permitting operation of said main control valve by said thermostat to supply fuel to said main burner only when the armature is in attracted position. and manually actuable means for simultaneously moving said armature and opening said pilot control valve, and a holding member actuated by said manually actuable means to maintain said main control valve closed while said armature is moving to attracted position.

5. A combined temperature and safety control comprising a valve, thermostat means operable on one side of said valve for moving said valve to open position, electromagnetic means having an armature movable from attracted to released position to become operable on another side of said valve for moving said valve to closed position against the action of said thermostat means, manually operable means for resetting said armature to attracted position to permit operation of said valve by said thermostat means, and means operable on said valve in place of said armature and independently thereof for holding said valve in closed position during the resetting operation.

6. A combined temperature and safety control comprising a valve, thermostat means operable on one side of said valve tor moving said valve to open position, electromagnetic means coaxial with said thermostat means on the opposite side of said valve, an armature movable between attracted and released positions relative to said electromagnetic means, an abutment carried by said armature and engageable with said valve upon said movement to released position for moving said valve to closed position against the action of said thermostat means, manually operable means for resetting said armature to attracted position and moving said abutment away from said valve to permit operation thereof by said thermostat means, and means carried by said abutment and slidable relatively thereto by said manually operable means into engagement with against the action of said thermostat means, and

manually operable means for resetting said armature to attracted position to permit operation of said valve by said thermostat and for holding said valve in closed position during the resetting operation, said means including a pivoted lever operfor fuel burners having main and pilot burners,

comprising a main control valve biased to closed position, a pilot" control valve biased to closed position, thermostat means for moving said main valve to open position against its bias, thermoelectric means responsive to operation of the pilot burner, an electromagnet adapted to be energized by said thermoelectric means when said pilot burner produces a flame, an armature device for said electromagnet operatively engageable with said main valve for moving said valve to closed position in opposition to said thermostat, means biasin said armature device toward operative engagement with said main valve, a man! ually operable reset stem reciprocable relative to said armature device, a pivoted lever having lost motion connection with said stem and engageable with said armature device for resetting it against its bias toward said electromagnet, means carried by said lever for moving said pilot valve to open position against its bias during the resetting operation, said armature being retained-by said electromagnet upon energization thereof, and a holding member secured to said reset stem and operatively engageable with said main valve for maintaining said valve closed during the resetting operation, said lost motion connection permitting withdrawal of said holding means by operation of the reset stem without corresponding movement of said lever so that sald'pilot valv remains held open during energization of said electromagnet.

V l 1 F. JACKSON.

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