US2707517A

US2707517A - Ignition and automatic pilot controls for fuel burners

Info

Publication number: US2707517A
Application number: US90151A
Authority: US
Inventors: Charles K Strobel
Original assignee: Robershaw Fulton Controls Comp
Current assignee: Robertshaw Controls Co
Priority date: 1949-04-28
Filing date: 1949-04-28
Publication date: 1955-05-03
Anticipated expiration: 1972-05-03

Description

M y 3, 1955 c. K. STROBEL 2,707,517

IGNITION AND AUTOMATIC PILOT CONTROLS FOR FUEL BURNERS Filed April 28. 1949 3 Sheets-Sheet l I INVENTOR. CHARL E6 A. 67-30551.

C. K. STROBEL May3 1 Filed April 28. 1949 3 Sheets-Sheet 2 8% m I J A. n n m 0 I @6 m1 1 u Q. 8 e lllll a 4 ue 7 u w n H g N 81 8N. g ln n u C W 3w u m m rill" v. w 0 mm 7 98 N2 B m mm W M .1}. e9 r llll 1 g 2 3. 3--- r {\kka Mme I:

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y 3, 1955 c. K. STROBEL 2,707,517

IGNITION AND AUTOMATIC PILOT CONTROLS FOR FUEL BURNERS Filed April 28. 1949 I5 Sheets-Sheet I5 INVENTOR.

CH4 e4 5: A. 67120554.

69 7' TOR/V5)? United States Patent IGNITION AND AUTOMATIC PILOT CONTROLS FOR FUEL BURNERS Charles K. Strobel, Pittsburgh, Pa., assignor to Robertshaw-Fulton Controls Company, Greensburg, Pa., a corporation of Delaware Application April 28, 1949, Serial No. 90,151

2 Claims. (Cl. 158-130) Fuel burners, such as gas ranges and the like, are

usually provided with constant burning pilots, for the top cooking burners and the oven burners. This practice involves a normally undesired source of heat and increases the expense of operation of the appliance. The present invention seeks to retain the advantages of socalled automatic ignition and pilot control which has heretofore been possible with such constant burning pilots. At the same time, however, an object of this invention is to eliminate the undesirable features attendant upon the use of constant burning pilots.

Accordingly, the invention provides that all burners in a gas range, for example, can be ignited from a single igniter while retaining the automatic pilot control to prevent escape of unburned fuel. The invention embodies a catalytic igniter with separate flash-tubes leading therefrom to both the top and oven pilot burners for selective ignition. Means responsive to a flame at the oven pilot burner are employed to control the how of fuel to the main burner so that the automatic pilot control feature is preserved.

In a preferred embodiment of the invention, a thermally operable valve controls the oven burner fuel supply and is retained in open position during the existence of the pilot burner fiame. Such a valve may be either directly operable by the thermally responsive means or may be electromagnetically operated in response to energy supplied by thermoelectric means exposed to the pilot burner fiame. Both expedients are disclosed in detail herein in connection with the accompanying drawings which show the preferred embodiment by way of example and wherein Fig. l is a schematic view in perspective of a gas burniug apparatus, such as a gas range, having the ignitio and automatic pilot control applied thereto,

Fig. 2 is a somewhat schematic plan view, shown F partly in section, of the ignition and automatic pilot control shown in Fig. 1,

Fig. 3 is a perspective enlarged view of a detail of the structures shown in Figs. 1 and 2,

Fig. 4 is a top plan view of a gas burning apparatus, such as a gas range, showing a modified form of ignition and automatic pilot control, and

Fig. 5 is a front elevation, partly in section, of the gas burning apparatus shown in Fig. 4.

Referring more particularly to Figs. 1, 2, and 3 of the drawings, the automatic pilot control and ignition apparatus is shown with a cooking range having the usual oven burner and a plurality of top burners 12. Ordinarily, four or more top burners 12 are provided in such ranges but only two such burners are shown for the purpose of clarity in illustration. As is customary in equipment of this nature, the various burners receive fuel from a manifold 14 connected to a source of fuel supply. Thus, the top burners 12 are connected to the manifold 14 by pipes 16 and the fuel supply therein is under control of the usual manually operated gas cocks 17.

The fuel supply to the main burner 19 is under concated within an end casing 70.

Patented May 3, 1955 trol of a combined main fuel valve and thermostat 20 which may be of the type disclosed in Weber Patent No. 2,303,011. As structures of this nature are well known, only the essential portions thereof will be described herein and reference may be had to the aforementioned patent, if desired, for further details. The combined valve and thermostat 20 is shown more clearly in Fig. 2 of the drawings and comprises a main casing 22 within which a tapered valve member or cock 24 is adapted to rotate. The valve member 24- is hollow and is provided with a port 26 in its side wall adapted to register with an inlet opening 28 formed in the main casing 22. A pipe 29 serves to connect the inlet 28 with the manifold 14 for supplying fuel to the interior of the valve member 24 when the latter is in open position.

Rotation of the valve member 24 is effected by the provision of a reduced stem 30 which projects from the larger end of the valve member 24 into an end casing or cover 32 secured to the main casing 22. A dial or handle 34 is mounted exteriorly of the cover 32 on a tubular projection 36 which fits closely in the cover 32 and is spaced from the stem 30. The proiection terminates at its inner end within an annular recess 3 formed in the main casing 22 adjacent the larger end of the valve member 24. A sleeve 4. 0 is slidably mounted within the projection 36 and is provided with an end flange 42 which enters a slot 44 in the inner end of the projection 36 and provides means by which rotation of the dial or handle 34 may be imparted to the sleeve 40.

The flange 42 extends radially beyond the projection 36 into engagement with a slot l6 formed in the cover 32 opposite the annular recess 38; the arrangement serving as will hereinafter be apparent to prevent rotation of the valve or handle 34 until axial movement thereof relative to the valve member 24 has occurred sufficient to move the sleeve 4%) from a retracted position and release the flange 42 into the recess 38.

The end of the sleeve 40 opposite the flange 42 is provided with a plurality of oppositely disposed tongues 48 which project therefrom into complemental slots (not shown) formed in the outer surface of a collar 50 secured to the end of the valve stem 30. That portion of the valve stem 39 which is located within the sleeve 40 is preferably reduced in diameter forming a shoulder 52 against which one end of the coil spring 54 abuts. The opposite end of the spring 54 abuts a plurality of projections 56 formed on the sleeve 40 and located intermediate the ends thereof and serves to bias the sleeve 40 to its retracted position.

The valve stem 30 is provided with an operating shaft 613 connected by a pin and slot connection 62 to an eX- tension 61 which projects through the main casing 22. The opposite end of the extension 61 carries a reciprocable valve member 64 cooperable with an annular valve seat 66 formed in the casing 22. A projection 68 on the valve member 64 has threaded engagement with a nut 62 lo- The nut 69 is anchored to the end casing 70 in such manner as to permit relative axial movement while preventing relative rotation therebetween. Due to the connections described, it is apparent that rotation of the dial 34 will not only rotate the main valve member 24 but will also position the valve 3 tuner 74. As will hereinafter be explained, the pilot burner 74 may be dispensed with if desired.

Thermostatic means for operating the valve member 64 include a diaphragm element 80 positioned within the end casing 'ill in operative engagement with the projection 68 and having the usual capillary tube 82 and bulb element 8d associated therewith. The bulb element 84 may be located in the oven or other chamber being heated by the main burner 10. When the bulb member 84 rc sponds to the temperature indicated on the dial 3+5, then the diaphragm element will be sufficiently expanded to seat the valve member 64 on its seat 66 against the bias of the coil spring 86 which is operative between the valve member 6 and the end of the main valve member 24.

The flow of fuel in the pipe 13 to the main burner 16 is also under the control of a thermomagnetic control device designated generally by the reference numeral 38. This thermomagnetic control device 88 is interposed in the main fuel pipe it; in proximity of the top burners 12 between the combined main fuel valve and thermostat 2t) and the oven burner 16". The control device 38 comprises a casing 96 having an inlet connection 92 extending through the side wall thereof adjacent one end and communicating with an axial main fuel chamber 94 therein. The main fuel chamber 94 is provided with a partition 96 having an axial opening 98 to which fuel may flow from the inlet 92 to an outlet 11H) formed in the wall of the casing 9 at the opposite end of the chamber 94. The inlet 92 and outlet 19!) serve as connections for opposite ends of the fuel pipe 18 as will be apparent.

- 98 is controlled by safety valve member is movable into and out of engagement with a valve seat formed on the side of the partition )6 adjacent the inlet opening 92. The valve member 102 is secured to a valve stem Hi4 which extends through the opcni 9t; and has slidable engagement with a closure disc 6 which seats on the opposite side of the partition as. The purpose of the closure disc 166 is to interrupt the flow of fuel through the passage d8 when the valve member 102 is moved out of engagement with its seat during the resetting operation to be described hereinafter.

The closure disc ms is reduced opposite its seating area to slide within an annular projection or housing 108 on the bottom of the chamber 94. A coil spring 110 is carried by the reduced end of the closure disc 106 and is operative between the housing 168 and an abutment 152 formed on the reduced end. it should be observed that when a force is applied to the abutment 112 to move the closure disc Hi5 into engagement with its seat, the coil spring 11% will be compressed. When the force is removed, the bias of the spring 110 will serve to return the closure disc 36 to its open position relative to the seat. However, a yieldable connection is also provided between the closure disc 105 and the valve member 162 to permit relative movement thercbetween and this connection forms an override mechanism which includes a coil spring 114 housed within an axial recess projecting from the closure disc 196 into the reduced end thereof and being operative between the bottom of the recess and the end of the valve stem 104.

The end of the casing 90 adjacent the inlet 92 is provided with a closure cap 116 having a magnet housing 113 closely engaging the inner wall thereof. The closure cap 116 at its outer end embodies a threaded terminal connection 126. The magnet housing 118 supports a horseshoe magnet 122 which is provided with the usual winding 124 having one end grounded on the closure cap 118 and the opposite end secured to the terminal connection 126. The valve stem 104 projects into the magnet housing 118 and the electromagnetic device is completed by the provision of an armature 126 which is carried by the valve stem 104 for cooperation with the pole faces of the magnet 122.

It should be noted that the armature 126 is normally spaced from the magnet 122 a less distance than the closure disc 1% is spaced from its scat on the partition 96. Thus, after the armature 126 is in attracted position against the pole faces of the magnet 122, the override spring 114 permits further movement of the closure disc 1% relative to the valve stem ill-l. When the valve member 102 is fully disengaged from its seat, then the armature 126 is in attracted position relative to the pole faces of the magnet 122. The valve member 102 is biased to its seat and the armature 126 to its released position by the provision of a coil spring 123 operative between the valve member 102 and the bottom of the magnet housing 118.

The control device 88 also includes means to control the flow of fuel to a flash pilot burner .136 and an auxiliary pilot burner 132. The flash pilot burner 13') is located in the oven compartment adjacent the main burner 10 while the auxiliary pilot burner 132 is located adjacent the top burners 12. Both pilot burners 139, 132 are supplied with fuel by the pipe 134 extending from the control device the auxiliary pilot burner 132 being conveniently connected to the pipe 134 by a branch pipe 136. This fuel is under control of the thermomagnetic control device 88 by connection of one end of a pipe 138 to an inlet opening 140 extending through the wall of the casing and having its opposite end connected to the pipe 78. The inlet opening communicates with an auxiliary fuel chamber formed axially of the casing 98 and separated from the main fuel chamber 94 therein by the housing 103. The bottom wall of the chamber 142 is apertured to provide passage for fuel from the inlet 14% to an outlet 144 formed in the wall of the casing 90 on the opposite side of the bottom wall and adapted for connection to the fuel pipe 134.

Passage of fuel from the inlet 140 to the outlet 144 is controlled by an auxiliary valve member M6 which is movable into and out of engagement with the apertured bottom Wall of the chamber 142 by operation of a valve stem 34-3 which is secured to the valve member 146 and extends on either side thereof. One end of the valve stem 148 is located in the chamber 3.42 and terminates adjacent the abutment 112 with a sealing diaphragm 143 interposed therebetween. The auxiliary valve member 146 is biased into engagement with the apertured bottom wall of the chamber 142 by a coil spring 150 carried on the opposite end of the stem 142 and which is operative between the bottom wall and a collar 151 carried on the valve stem 143. This opposite end of the valve stem 148 terminates beyond the collar thereon for operative engagement with a second sealing diaphragm 152. A reset stem 154 extends from the opposite side of the diaphragm 152 through the bottom wall of the casing 90 and is provided with a button 156 exterior of the casing 90 and by means of which the reset stem 354 may be rcciprocatcd.

The electromagnet, comprising the winding 124 and horseshoe magnet 122, is adapted to be energized by current generated from a thermocouple 158 which is connected by suitable leads to the winding 124 at the terminal connection 120. The thermocouple 158 is located so that the hot junction thereof will be heated by a flame from a thermocouple heating burner 169 which receives a supply of fuel from the pipe 134 which also supplies fuel to the flash pilot burner 13%. it will be apparent that the thermocouple heating burner 160 and the portion of the pipe 134 beyond the branch pipe 136 could be dispensed with if the ignition pilot burner 74 is arranged to heal. the thermocouple 158 and also ignite the main burner it) and the burner 139 is connected into the supply pipe 78.

As previously indicated, this invention is more particularly directed to the provision of a catalytic igniler for the burners of the apparatus so that a constant burning top pilot burner may be dispensed with. Accordingly. a catalytic igniter 161 is supported in a housing 163 and preferably spaced an equal distance from each of the top burners 12. Any of the various WBll-hl'lOV/il forms of catalytic igniters may be used for the purpose disclosed herein and the material of which the igniter is made forms no part of the present invention. As is well-known, small pellets, wires, coils or other forms of catalytic material will glow and ignite spontaneously when immersed in a steam of gaseous fuel. It is preferred that the igniter 161 of this disclosure be a cold type catalyst although other forms are not considered beyond the scope of this disclosure.

A flash tube 162 extends between the auxiliary pilot burner 132 and the catalytic igniter 161 to effect ignition of the pilot burner 132. A separate flash tube 165 is provided from the igniter housing 163 to each of the top burners 12. And elongated flash tube 164 is provided between the auxiliary pilot burner 13-2 and the flash pilot burner 130 which is remote therefrom. In addition, a branch flash tube 166 extends from the flash tube 164 adjacent the flash pilot burner 130 to the thermocouple heating burner 160. It will be understood that if the burner 168 is dispensed with then the

flash tubes

164 and 166 would be arranged to ignite the ignition pilot The control device 88 is provided with a bracket 168 extending toward the top pilot burners 12 and forming a support for the auxiliary pilot burner 132. The bracket 168 is provided with a support 170 upon which a pair of pivoted members 172, 174 are rotatably and separately carried. The pivoted members 172, 174 constitute a latch and have interengaging means thereon for rotating one from the other. Thus, the member 172 is provided with a projection 176 which is adapted to operably engage a complemental projection 1'78 carried on the member 174. The member 174 is provided with a slotted end 186 opposite the projection 178 thereon and being oflset from the longitudinal axis.

Extending between the slotted end 180 and the reset button 156 is a timing device comprising a bimetal element 182 which is retained in position on the reset button 156 by the provision of a transverse slot 184 disposed transversely of the longitudinal axis or" the reset stem 154. Pivotal movement of the member 174 is restricted by its alternative engagement with oppositely disposed shoulders 185 formed on the support member 17%). As indicated in the drawing, when the reset button 156 is unoperated the birnetal element 182 occupies a position at an angle to the axis of the reset stem 154. In this position the birnetal element 182 is offset from the auxiliary pilot burner 132 which projects through the bracket 168 substantially midway between the control device 88 and the support 170.

Manually operable safety means for moving the bimetal element 182 and latching member 174 into substantial alignment with the axis of the reset stem 154 are provided. It will be apparent that in such position the birnetal element 182 will be subject to the heat of the flame of the auxiliary pilot burner 132. Moreover, in this position the reset button 156 will be forced inwardly relative to control device 88 to effect the resetting operation. The manually operable means include connecting means between the dial of handle 34 and the pivoted member 172 and takes the form of a connecting rod 186 supported at one end in an apertured bracket 188 carried by the pivoted member 172 and providing sufficient clearance for rotation of the member 172 during axial movement of the connecting rod 186. An ad justing element for the connecting rod 186 takes the form of a nut 1% threadedly engaging the end of the rod 186 which projects through the bracket 188 and having a bearing thereon for this purpose.

The opposite end of the connecting rod 186 is pivotally mounted on a third pivoted member 192. The pivoted member 192 is rotatable on a bracket 194 projecting from the cover 32 and serves with the pivoted member 172 to support the connecting rod 186 in substantially parallel arrangement with the control device 88 and the combined valve and thermostatic mechanism 20. A tension spring 196 extends between one end of the third pivoted member 122 and a lug 198 formed on the connecting rod 186 for the purpose of returning the pivoted member 192 to normal position after operation of the resetting device. It will be apparent that the spring 196 would not be essential if suflicient bias force may be obtained from the pivoted members 172, 174 and the birnetal element 182 to effect the desired result.

As shown more clearly in Fig. 3, the bracket 194 also supports a slidable key element 280 having an enlarged end 202 engageable with the free end of the pivoted member 192 and having its opposite end engageable with an operating member or pin 284 projecting from the dial or handle 34. The pin 204 is located on the dial 34 in such position that the described engagement will occur when the shut-off cock or valve member 24 is in its full closed position. Thus, upon axial movement of the dial 34 to free the flange 42 from the slot 46 as described herein, which motion is an essential preliminary to rotary motion of the dial 34, the slidable element 200 will be moved axially relative to the bracket 194. In order that return movement of the dial 34, while held inwardly to the initial position shown, will not be interfered with by the slidable member 200, a pivoted tooth member 206 is provided on the slidable member 200 for engagement by the pin 204. The arrangement is such that the tooth member 266 will be rotated by the pin 204 as the dial 34 is returned to the 011 position. A flat spring 208 may be secured at one end to the slidable member 200 and have its opposite end engaging the tooth member 206 to return the latter to initial position when the pin 204 no longer exerts a torque thereon.

In the operation of the device disclosed in Figs. 1, 2 and 3, any one of the top burners 12 may be placed in operation by merely turning the appropriate gas cock 17 to its open position. The resulting flow of fuel from a top burner 12 will enter the associated flash tube and impinge on the igniter 161. This fuel becomes ignited and the flame travels back through the flash tube and ignites the top burner 12. The operation is precisely the same as if a constant burning pilot were used in place of the igniter 161.

The oven burner 10 may be ignited in a simple manner and it may be assumed that the parts are in the position shown in the drawing. The dial or handle 34 is then pushed inwardly to release the flange 42 from the slot 46 preparatory to rotating the dial 34 to a desired temperature setting. The initial axial movement of the dial 34 causes the pin 204 and the slidable member 288 to move inwardly also and the slidable member 208 thereupon rotates the pivoted member 192 in a clockwise direction. The connecting rod 186 is thus pulled to the right as viewed in the drawing and the interengagement of the pivoted members 172, 174 causes rotation of the latter in a counterclockwise direction on the support 170. The end of the birnetal element 182 which is engaged with the pivoted member 174 is thus caused to move in a clockwise direction whereupon the birnetal element 182 assumes the broken line position shown in Fig. 2 of the drawings.

The rotation of the birnetal element 182 to the broken line position causes the reset button 156 and stem 154 to be forced inwardly and to be maintained in such position during such time as the birnetal element 182 remains unheated. The diaphragm 152 and the auxiliary valve stem 148 move to the left to open the auxiliary valve member 146. Such movement of the auxiliary valve stem 14% is suflicient to overcome the bias of the spring 11% and move the closure disc 166 against its seat on the partition 96. The valve member 1&2 is moved away from its seat on the opposite side of the partition 9-5 while the armature 126 is moved into engagement wtih the pole faces of the magnet 122. it should be noted that immediately prior to engagement of the closure disc 196 with its seat, that the armature 126 has been moved into ongagement with the pole faces of the magnet 122, but the closure disc 196 can thereafter be moved into engagement with its seat due to the provision of the override spring 11- between these elements.

While the description of the various movements which occur upon inward movement of the dial or handle 34 may appear lengthy, it will be apparent that only a momentary lapse of time has occurred prior to rotative movement of the dial 34 which now is conducted. In other Words, the inward pushing action and subsequent rotation applied to the dial 34 are part of a single manual operation which is continuous. Assuming that the dial or handle 34 is now rotated to a desired temperature setting, then the port 26 in the shut-off cock or valve member 24 becomes registered with the inlet opening 28 and fuel is supplied by way of the inlet pipe 29 from the manifold 14 to the interior of the valve member 24. Moreover, due to the threaded engagement of the thermostatic valve member 6 with the nut 69, this valve member is now disengaged from its seat 66 a predetermined distance corresponding to the selected temperature setting on the dial 3+3. Fuel is thus permitted to flow through the outlet 72 and pipe 18 to inlet 92 of the control device 83, through the pipe '78 to the i nition pilot burner 74 and also by way of branch pipe 1.38 to the control device 88.

As the auxiliary valve member 146 is now disengaged from its seat, the fuel from the branch pipe 133 passes by way of inlet 1 4i) and outlet 144 to the pipes 136 and 134. The auxiliary pilot burner 132, the flash pilot burner 130 and the thermocouple heating burner 16% are now supplied with fuel. pilot burner 132 travels through the flash tube 162 to the catalytic igniter 161 where it is ignited. The liame then travels back through the flash tube 162 and ignites the auxiliary pilot burner 132. The flash pilot burner 130 and the thermocouple heating burner 160 are ignited in similar fashion from the auxiliary pilot burner 132 through the elongated flash tube 164. The ignition pilot burner "i i also becomes ignited from the thermocouple heating burner 16%. It will be observed, however, that no fuel can flow to the main burner 19 at-this time due to the engagement of the closure disc 3W6 with its seat and the consequent shutting off of flow of fuel between the inlet 92 and the outlet 1% of the control device 83.

After a predetermined tlme-deiay during which the bimetal element 182 becomes sufficiently heated by the flame from the auxiliary pilot burner 132, the element warps and trips the latch comprising pivoted members 174- and 172. As the pivoted member 174 is rotated in a clockwise direction when tripped, the bimetal element 132 is rotated in a counterclockwise direction about the slotted end 18-. in the reset button 156 as a pivot. The bimetal element 182 is thus moved out of the path of a flame from the auxiliary pilot burner 132 to its initial cold position and simultaneously the force upon the reset button 156 is released. The connecting rod 186 is moved to the left, partly under bias of the spring 196 so that the pivoted member 192 and slidable element 2% resume their initial positions shown in the drawing. it will be noted that the pin 264 has been rotated with the handle or dial 34 out of operative engagement with the tooth member 206 so that resumption of the initial position of the slidable element Zilt) is not interfered with. However, the dial 3 3 is still occupying an inward position and will maintain such position until the flange 42 on the sleeve 49 can again enter the slot 46. Such entry of The fuel from the auxiliary 8 the flange 42 occurs when the dial 3*; is returned to the initial off position shown in the drawing and is not effective at this time.

The system has now assumed its steady-state operating condition. The retraction of the reset stem 154 has caused the auxiliary valve member 146 to become engaged with its seat to prevent the flow of fuel from the inlet M0 to the outlet 14-4 so that the flow of fuel through the pipes 134 and 136 to the flash pilot burner thermocouple heating burner 160 and time for heating the bimetal element 182 sufficiently to cause it to warp is made long enough so that the thermocouple I 3 can become sufficiently heated by the flame from the thermocouple heating burner 65) to gen current for energizing the electromagnet 122,

124 before the auxiliary valve member 146 is moved to .losed position. As the armature 126 is now held in attracted P01 lil3i1 against the pole faces of the magnet 122, t.c valve member 302. remains open while the closure disc 1% becomes disengaged from its seat under the bias of the coil spring 110. Flow of fuel from the inlet 92 and the outlet 190 to the main burner is now permitted. This burner is ignited by the flame at the ignition pilot burner 74 or, where the latter is dispensed with, by the flame at the thermocouple heating burner loll.

if at any time during the operation of the apparatus, the thermocouple E58 ceases to be heated by the flame :rorn the ignition pilot burner 74 or, the main burner 1'3 where the ignition pilot burner is dispensed with, then the armature 26 will be released from the pole faces of the magnet 153.2 causing the valve member 102 to become engaged with its seat and prevent flow of fuel to the main burner 15). The dial or handle 34 may be operated in a counterclockwise direction to its original 017 position upon termination of the oven burner operation. During this return movement of he dial 34 the pin 234 will engage and rotate the toothed member 2'36 so that the return movement is not interfered with.

Cross reference is made to my copending application, Serial No. 790,204 filed December 6, 1947, now Patent No. 2,628,677.

It is considered within the scope of this disclosure to provide the auxiliary pilot burner 13?. with an individual catalytic igniter. in such arrangement, the auxiliary pilot burner 132 would be provided with a second port for the purpose of ignition from the individual catalytic ignitcr and the flash tube 162 would be dispensed with. Such an arrangement would have the desirable feature that the oven catalytic igniter would be subjected to the Flame and combustion products only during the relatively short oven starting period. A further modification of the arrangement hereinbefore disclosed is shown in Figs. 4 and 5 to which reference will now be had.

Referring now more particularly to Figs. 4 and 5, a common form of rod and tube thermostat 210 has been substituted for the thermomagnetic type of control previously disclosed. in such event it is apparent that no connection is necessary between the oven thermostat 2? and the automatic pilot control due to the absence or any necessity for a resetting operation. Accordingly, the rod and tube thermostat 219, constituting the automatic pilot control of this embodiment, is provided with the usual valve member (not shown) for controlling flow of fuel in the pipe 18 leading to the main burner The rod and tube element 212 of the th mostat extends toward the main burner 1' for ex.osure to the flame from a pilot burner 214 which located to ignite the main burner 16. The pilot burner 23.4 is supplied with fuel through a bypass connection 216 from the oven thermostat 20 so that, as is customary in such devices, the flow of fuel 9 to the pilot burner 214 is not cut ofl when the oven thermostatic valve operates to shut off the main burner supply.

Ignition of the pilot burner 214 is effected by an elongated flash tube 218 which extends from the catalytic igniter 161 to adjacent the pilot burner 214. As in the previous embodiment, the catalytic igniter 161 is supported in a housing 163 intermediate the four top burners 12 of the gas range. Also as in the previously described embodiment, the four top burners 12 are provided with separate flash tubes 165 leading from the housing 163 and effective for causing ignition from the catalytic igniter 161.

In the operation of the device shown in Figs. 4 and 5, the turning on of a gas cock 17 will cause a gas-air mixture to travel through the flash tube 165 associated with the related top burner 12. Such combustible mixture is ignited by the catalytic igniter 161 and the flame will travel back through the tube 165 and ignite the top burner 12.

When the oven thermostat 20 is turned to a desired temperature setting, then a gas-air mixture from the manifold 14 is admitted to the main fuel pipe 18 and also to the by-pass connection 216. As the rod and tube thermostat 210 is interposed in the

main fuel pipe

18 and 1 is yet unheated, then no fuel can flow to the main burner 10. The fuel in the by-pass connection 216 enters the flash tube 218 and is conveyed to the catalytic igniter 161. The resulting flame travels back through the tube 218 and ignites the fuel at the pilot burner 214. The flame from the pilot burner 214 serves to heat the rod and tube element 212 and causes the valve member of the rod and tube thermostat 210 to open and admit fuel to the main burner 10. As the pilot burner 214 can then ignite the fuel at the main burner 10 the system is placed in steady state operation.

It will be apparent that in both embodiments of the invention many changes may be made in the details of construction and arrangement of parts without departing from the scope of the invention so that this description and accompanying drawings are intended by way of illustration only and are not to be construed in a limiting sense.

I claim:

1. An ignition and automatic pilot control for fluid fuel burners having a main burner and a pair of pilot burners comprising a catalytic igniter adapted to respond to a flowing fuel-air mixture for producing a flame at the pilot burners, a control valve member having open and closed positions for controlling the supply of fuel to the main burner, electromagnetic means operatively associated with said control valve member for holding the same in said open position when energized, thermoelectric means adapted to be responsive to the heat of the flame at one of said pilot burners for energizing said electromagnetic means, and resetting means operative for positioning said valve member in said open position and including thermal timing means adapted to be responsive to the heat of the flame at the other pilot burner for returning said resetting means to inoperative position upon completion of said resetting operation.

2. An ignition and automatic pilot control for gas ranges having top burners, a main oven burner and a pair of pilot burners, comprising a catalytic igniter located adjacent the top burners, flash tubes extending between said igniter and the top burners, fuel supply means for said burners, a combined thermostatic regulator and main control valve device for controlling said fuel supply to I; the main burner, thermally responsive means operably associated with said regualtor and responsive to oven temperatures for regulating said fuel supply to the main burner in accordance therewith, a bypass connection from said device to one of the pilot burners, an oven flash tube for conveying a combustible mixture from said one pilot burner to adjacent said igniter and producing a flame at said one pilot burner, 21 control valve member having open and closed positions for controlling the fuel supply to the main burner, electromagnetic means operatively associated With said control valve member for holding the same in said open position when energized, thermoelectric means adapted to be responsive to the heat of said flame at the one said pilot burner for energizing said electromagnetic means, a flash tube extending between said igniter and the other said pilot burner, and resetting means operatively associated with said device and being operative for positioning said control valve member in open position, said last means including thermal timing means adapted to be responsive to the heat of the flame at the other pilot burner for returning said resetting means to inoperative position upon completion of said resetting operation.

References Cited in the file of this patent UNITED STATES PATENTS 623,572 Simonini Apr. 25, 1899 1,148,409 Roessler July 27, 1915 1,173,851 Owen Feb. 29, 1916 2,063,834 Bast et al. Dec. 8, 1936 2,078,576 Laghetto Apr. 27, 1937 2,098,192 Matthews Nov. 2, 1937 2,113,064 Voice Apr. 5, 1933 2,138,925 Kahn -1 Dec. 6, 1938 2,360,607 Kauffman et al. Oct. 17, 1944 2,407,729 Taylor Sept. 17, 1946 2,487,752 Cohn Nov. 8, 1949 FOREIGN PATENTS 443,240 Great Britain Feb. 24, 1936