US2604153A

US2604153A - Safety control and ignition systems for fuel burners

Info

Publication number: US2604153A
Application number: US620320A
Authority: US
Inventors: Charles K Strobel; Stanley J Lakota
Original assignee: Robertshaw Fulton Controls Co
Current assignee: Robertshaw Controls Co
Priority date: 1945-10-04
Filing date: 1945-10-04
Publication date: 1952-07-22
Anticipated expiration: 1969-07-22

Description

July 22, 1952 C. K- STROBEL ET AL SAFETY CONTROL AND IGNITION SYSTEM FOR FUEL BURNERS Filed Oct. 4, 1945 3 Sheets-Sheet 1 CHflkLES KMLPL r EQJ L \STANLEY JOHN Lnxom.

-WlTNESSES:

Q'D'ATTORNEY y 22, 1952 c. K. STROBEL ETAL 2,604,153

SAFETY CONTROL AND IGNITION SYSTEM FOR FUEL BURNERS Filed 001;. 4, 1945 3 Sheets-Sheet 2 WITNESSES:

c/m/eLEs KENN$90BE arm/1.5) JOHN LnKom.

" ATTORNEY C. K. STROBEL ET AL July 22, 1952 SAFETY CONTROL AND IGNITION SYSTEM FOR FUEL BURNERS I 3 Sheets-Sheet 3 Filed Oct. 4, 1945 INVENTORS c/MRLEs KEN/V50);

WITNESSES:

" ATTORNEY Fatented july 22, 1952 SAFETY CONTROL AND IGNITION SYSTEMS FOR FUEL BURNERS Charles K. Strobel and Stanley J. Lakota, Pittsburgh, Pa., assignors to Robertshaw-Fulton' Controls Company, a corporation'of Delaware Application October 4, 1945; Serial No. 620,320 V 1 This invention relates to safety control and ignition apparatus for gaseous fuel burners and, more particularly, to electrically operated safety controls for use with flash tube ignition systems for oven burners.

In apparatus of this general character used on domestic gas ranges it is desirable that the electrically operable control be independent of sources of supply extraneous of the system itself. A satisfactory source of electrical energy may be derived from a thermocouple exposed to a flame at one of the burners and forming partjof a L thermomagnetic safety control device. However, it has been necessary that manual effort be'exerted for a more or less prolonged period to place such a device in operation or to reset it due to the 13 Claims. (Cl. 158-133) I ratus is shown in connection with a cooking range having the usual oven burner l0 and top pilot burner I2 located remotely from the oven burner Hi. As is custo'maryin equipment of this nature, the various burners're'ceive fuel from the mani fold It connected to a source of fuel supply. In this embodiment, the top pilot burner i2 is con-' nected by a pipe l6 to'the manifold M and isof the c onstant burning type. v Q

Themain oven burner I0 is supplied with fuel from'the manifoldjd by a main fuel pipe-l8 and relatively weak current available for holding purposes only.

A prime object of this invention is to place an entiresafety control and ignition apparatus in operation. by turning on the main fuel cock of the range.

An object of this invention is to automatically reset a thermomagnetic safety device byplacing a burner in operation.

Another'object of the invention is to automatically discontinue the resetting operation after the system is placed in operating conditiorn Another object of the invention is to control the entire safety and ignition apparatus by the self-contained thermoelectric means.

Another object of the invention isto prevent flow of fuel to the oven burner until-safety conditions have been establishedand to discontinue such flow at any time that such conditions cease to exist.

bodying the invention;

Fig. 2 is a longitudinal sectional view of the electromagnetic control device shown in Fig. 1;

Fig. 3 is an elevation of the resetting device for the control device shown in Fig. 2;

Fig. 4 is a front elevation of another portion of the resetting device; and

Fig. 5 is a plan View of the resetting device shown in Fig. 4.

Referring more particularly to Fig. 1 of the drawings, the safety control and ignition appathe fuelsupply therein is under control'ofmeans comprising a mainfueljcock-mfwhichmay also embody the usual thermostatic control device fad justable together withthe cock by" knob' and being responsive to temperatures intlie -oven where th'efburner'l ll is located. As combined fuel cocks and thermostatic "devices are well known; further description is deemedunnecessary it be ing understood that the thermostatic de'vi'ce is capable of controlling the'fiow of fuel in the pipe [8 independently of the fuel cock 2B when'the latter has once been opened. The flow'of fuelin the pipe Hi to the main burner I0 is thussubject tothe throttling action of the thermostatic devi'ce where included. I The flow offuelin the pipe E8 to the-main burner IE! is also 'under the control of a' thermomagnetic control .devicedesignated generally-"by the reference xiumeral224 This thermomagnetic control device 22 is interposed in the main fuel pipe IS in proximity of the top pilot burner I2 between the main fuel cock 2!) and the oven burner l0. As shown more clearly in'Fig. 2,: the control device 22 comprises a casing 24 having an inlet connection 26': extending through the side wall of the casing24. adjacent one end and'communicating with a main fuel chamber 28 extendingraxiall'y of "the. casing 24: The main fuel chamber 28 is provided with a partitioniitl having an opening 32 therethrough throughswliich fuel may flow from the inlet 26 to an outletfid'formed in the wall of the casing'24 at the' o'p'posite end of the chamber 28.. The inlet 26 an-dfioutlet 34 serve as connections for opposite ends of the fuel pipe l8 as will be apparent from Fig.5.1 ofthe drawings.

The passage 32 is controlledjby a safetyivalve 36 which-is movable into and out of engagement with a valve seat 38 formed on the side of the partition 30 adjacent the inlet opening 25. ,;The valve member 36 is secured to ayalve'stemcfl which extends through the opening 32 and has slidable engagement with a closure disc'll2. The purpose of the closure disc is to interrupt the flow of fuel through the passage 32 when the'valve member -35 is moved out of engagement with the seat 38 during the resetting operation to be described hereinafter. To this end, a second valve seat 44 is formed on the partition 36 on the side opposite the valve seat 38 and is adapted to be engaged by the closure disc 42 during the resetting operation. A guide portion 43 is formed substantially concentric with the closure disc 42 for cooperation with the walls of the opening 32 and may be serrated to permit free passage of fuel thereby until the closure disc is fully engaged; with its seat 44.

The bottom of the chamber 28 is provided with.

an annular projection or housing 46' in which a stem portion 48 of the closure disc isslidably mounted. A coil spring 56 is carried by the stem 48 and is operative between thehousing 46 and a collar 52 mounted on the stem 48. Thus, when a force is applied to the end of the stem 48 to move the closure disc 42 into engagement with its'seat 44, the coil spring 56 will be compressed. When the force is removed, the bias of the spring 56 will serve to returnthe closure disc 42 to its open position relative" to. the seat 44.

A yieldable'connection is provided between the closure disc 42and the valve member 36 toip'ermit relative movement therebetween as will be more apparent'hereinaft'er. To this end, there is provided an override mechanism in association with the closure disc 42 and valve stem 46 which may take the form of a coil spring 54 housed within an axial recess in the closure. disc stem 48 and operative between the bottom of the recess and the end-of the valve stem 46.

The endof the casing 24 adjacent the inlet 26 is provided'with a closure cap 56 having a magnet housing Eli-closely engaging the inner wall thereof. The closure cap 56 at its outer end supports a threaded terminal connection 66. The

magnet housing. 58 supports a horseshoe magnet 62 which is provided with the usual winding 64 having one end grounded on the closure cap 56 and the opposite end secured to the terminal connection 66. The electromagnetic device is completed by the provision of an armature 66 which is carried by the valve stem 46 for cooperation with the polefaces of the magnet 62. It will be noted that the armature is normally spaced from the magnet a less distance than the closure disc 42 is spaced from its seat. Thus, after the armature is inattracte'd position the override spring. 54 permits further movement of the closure disc relative to thevalve stem .46. When the valve member. .36. is fully disengagedfrom its seat38, then the armature 66 is in attracted relation relative to the pole faces of the magnet 62. The valve member 36 is biased to its seat 38 and the armature 66 to its released position by the provision of a coil spring. 68 operative between the valve member 36' and the bottom of the magnet housing 58.

The. control device 22 also includes means to control the supply. of fuel to a flash pilot burner .16 and an auxiliary pilot burner 12. As'shown in Fig. l, the. flashpilot burner 76 is located in the oven compartment adjacent the main burner I6 whilethe auxiliary pilot burner I2 is. located adjacent the top pilot burner I2. Both burners are supplied with fuel by a pipe 14 extending fromthe control device 22, the auxiliary pilotburner I2 being conveniently connected to pipe I4 by a branch pipe I6. The inlet forfuel-'tothe pipe I4 is connected tothe controldevice 22 and may take the form of a pipe 78 connected at-the opposite end to the main fuel cook 26; The fuel .m'th pipe I8 is preferably under control of "the main fuel cook 26 but is not controlled by the thermostatic device which may be included as previously described. Thus, when the main fuel cock 26 is open the flow of fuel in'the pipe I8 is not subject to the throttling action of .the thermostatic device as is the fuel in the'pipe I8.

As previously indicated, the thermomagnetic control device 22 is also adapted to control the flow of fuel to the flash pilot burner I6 and the auxiliary pilot burner'l2. To this end, as shown more clearly in Fig. 2, the pipe I8 is connected to an inlet opening 86 extending through the Wall of the casing 24- and communicating with an auxiliary fuel chamber 82 formed axially of the casing 24 and separated from the main fuel chamber 28 by the housing 46. In order to prevent leakage of fuel from one chamber to the other, the auxiliary fuel chamber 82 is provided with a diaphragm 84 extending thereacross adjacent the end of the closure disc stem 48 and maintained in position by means of a clamping ring 86 carried by the casing 24.

The bottom wall 88 of the chamber 82 is provided with a plurality of apertures 96 providing passage for fuel from the inlet 86 to an outlet-[92 formed in the wall of the casing 24 on the opposite side of the bottom wall- 88 and adapted for connection to the fuel pipe 14. Passage of fuel through the apertures 96 is controlled by an auxiliary valve member 94 which is movable into and out of engagement with the bottom wall 88 of the chamber 82 within which the Valve member 64 is located. A valve stem 96 is secured to the valve member 64 and extends on either side thereof. One end of the valve stem 96 is located in chamber 82 and terminates adjacent the diaphragm 84. The auxiliary Valve member 94 is biased into engagement with the wall 88 by a coil spring 91 carried on the opposite end of the stem 96 and which is operative between the wall 88 and a collar 68 carried on the valve stem 96. This opposite end of the valve stem 96 terminates beyond the collar 68 for operative engagement with a second diaphragm I66 which serves to prevent leakage of fuel from the casing 24 and is held in position by a second clamping ring I62 carried on the casing 24. A reset stem I64 extends from adjacent the underside of the diaphragm I66 to the bottom wall of the casing 24 and is provided with a button I66 exterior of the casing 24 and by means of which the reset stem I64 may be reciprocated.

The electromagnet, comprising the winding 64 and horseshoe magnet 62, is adapted to be energized by current generated from a thermocouple I68 which is connected by suitable leads II6 to the terminal connection 66. The thermocouple I68 is located so that the hot junctionv thereof will be heated by a flame from a thermocouple heating-burner H2 which receives a supply of fuel from the pipe 14 which also sup-pliesfuel to the flash pilot burner 76. If desired, an ignition pilot burner II4 maybe provided intermediate the thermocouple heating burner II2 and'the main burner I6 and may receive fuel from a' conduit I I6 connected to the pipe 18.

A system of flash tubes is provided for igniting the various burners of the system from the constant burning top pilot burner I2. Accordingly, a short flash tube I I8 is provided between the constant burning top pilot burner I2 and the auxiliary pilot burner 72, it being apparent that fuel from the pipe I6 flowing from the auxiliary pilot burner I2 will enter the flash tube I I8 and -be ignited from the constantburning pilot burner I2. The flame so created will then be conducted one'side of the channel-shaped portion I26. The.

back through the flash tube H8 and will ignite other arm of the lever I42-is engaged by a flexible the 'fuel flowing from the auxiliary pilot burner connection in the form of a cable or pull wire I50 7 I2. An elongated flash tube I20 is provided bewhich is'mounted on the bracket I24 and is protween the constant burning top pilot burner I2 5 vided with a coil spring I52 operative between the and the flash pilot burner I which is remote bracket I24 and the lever I42 for biasing the lever therefrom. This flash tube I20 serves to cause in a counter-clockwise direction. Asshown in ignitionof the flash pilot burner I0 in a similar Fig. 3. when the lever is thus biased the bimetal manner to that described in connection with the strip I36 is held in its angular position out of the flash tube I I8. In addition, a branch flash tube 1 path of the flameirom the auxiliary pilot burner I 22'extends from the flash tubeiI20 adjacent the 12. flash pilot burner I0 to the thermocouple heating The pull wire burner H2 and likewise serves to ignite theiuel I4,of the era and is connected by means now to flowing therefrom. .hedescribe'd th the main fuel cock 20 tor opera- 'The, heat of the flame from the thermocouple 5 by the knob 2|. To this end, the fuel cook heater. II 2 on thethermocouple I08 serves to provided with abracket I 54-extending laterally energize the, electromagnet sufliciently to .hold erefrom and carrying a support I56 through the armature :66 againstthe pole faces of themagnet 62 but this thermoelectric-current is int I V capable of moving the armature to this attracted 20 pivoted on a pin I60 carried by the bracket I54. position. Hence, resetting meansis provided for Movement of the lever I58 in one direction serves placing the armature 66 in attracted position and to exert a pull on the, wire I50 against the bias of willnow be described in connection with the dethe spring I52 and thus permits operation of the I50 extends toward the manifold hich the pull wire I50extends. The end of. the. Wi e, I50 is connected to a lever I58 which is tailed views in Figs. 3, 4 and 5 together with the latching element I30. Such movement of the more general showing ofFig. 1. lever I58 is effected by a slidable member I62 The control device 22 is provided withabracket having a hooked end I64 adapted to operatively I 24 extending toward the top pilotburner. I2, and engage the lever I 58. The slidable member I62 is forming a support for the auxiliarypilot burner movable in a path substantially normal to the l2. The bracket I24 is provided with .a channel axis of the fuel cock 2!] by means of a toothed xlshaped portion I26 at the end opposite theconportion I66 on the slidable member I62 being trol device 22 and projecting substantially midadapted for engagement with a lug ;I68 carried way across the bracket. The channel-shaped porby the knob 2|. The slidable member I62 issuption I26 provides spaced bearings for a pivot I28 ported on the bracket I54 and its movement relupon which a latching member I30 is mounted. ative thereto islimited by the provisionof a slot The latching member I 30 is preferably .made in I10 formed in the slidable member I62 for 00 two. parts, one slidable on the other which carries operation with apin I12 carried bythe b c the pivot, and biased apart by means of a coil I54. I spring I32 interposed therebetween. The slidable In er that the I63 On the b y portion of the latching member I30 is provided pass beyond the toothed portion, I66 on the slidwith a slot I34 extending across one end thereof able member I62, the latter is yieldably mounted and ofiset from the center. Extending between on the bracket I54 to permit such ii'i v m T0 the slot I34 and the reset button, I06 is a timing this end, the slidable member I62 s maintained device comprising a bimetal strip I 36 which is with the hooked end I64 thereon; e s m n retained in position on the reset button I06 by the withthe lever I 58 by meansof a s provision of a transverse slot I38 disposed cenwhich may be mounted at one end'p trally thereof. Pivotal movement of the latch-. and hav ngk tsopposite end hooked ing member I 30 is restricted by. its engagement tion I13 in. .d with a portion. of the channel-shaped member I26 in a counter-clockwise.diretztibngand by its engagement with a set screwfjlflfl carriedrby the channel-shaped p0rtionI26in the oppositedirec- 1 tion. v v

As shown more clearly 11mg: 3;when the *re- 7, p setting button I06 gp; at'ed' ,""the""bimeta'l oducing a flame and that the fuel cook. 20 strip I36 occupies ape tion an-ang1e--m n opened by means oirotation of the axis of the controldvice 22. hi'sapos itiom the ob I in a clockwise direction as viewed in Fig. bimetal strip I36 is offset from the auxiliary pilot "'4' tocause fuel to flow in the pipes; I8 and 16 as burner I2which projects through the bracket I24 far as the control device 22. Where, an ignition substantially midway between the control device pilot burner, such as-the burner H4, is provided. 22 and the channel-shaped portion I26. ,Manthis burner will-received-uel from pipes I6 and ually operated means for moving the bimetal H6 at this time. This operation of the knob strip I36 and latching member I30 into substan- ,2I will cause the lug I68 to be movedin a clocktial alignment with the axis of the control device wise direction into engagement with the toothed 22 are provided and'it will be apparent .:that'in portion I66 on the slidable member I62 causing such position the bimetal strip will be subject to 55 the pull wire I50 to be operated by means of the the heatof the flame from the auxiliary pilot lever I58. The latching lever I42 willthus be burner I2. Moreover, in this position the'reset moved against the bias of the spring I52 in a button I06 will be forced inwardly of the control clockwise direction causing the latching element device 22 to effect the resetting operation. I30 to move the adjacent end of the bimetal strip The manually operable means includes a lever I36, in a counterclockwise direction, untilit is I42 provided with an angular portion I 44 on one aligned with the axis of the control device 22 armzthereof having anaperture I46 therethrough and in the path of the flame from the auxiliary in which the slidable portion of the latching pilot burner I2. member I30 is received. The lever I42 is pivoted The set screw I40 is now engaged by the latchhe constant burning top jpi lot burner, I2

on a pin I48 projecting from the bracket I24 on 74 inc element I30 and it will be apparent that the auses the-reset stem upon the reset button [06.

7 reset button 106" maintained in sun position: while the". bimetal strip-is unheatedg due to the clockwiseZtorque: applied at the slot I34 *to the bimetal strip'il3fi and the counter-cloc wise torque applied. at the set screw Mil-to the latching elementl30; The lug 68 cm knob zi has moved under and released the toothed portion I BB during the opem. I mg mo ement of cock "20 due-to "the yieldable mounting of the slidable'memberilfit The 're-" 168. "The unheated bimetaI- Strip i-BG {remix-ism thelatched position independent or the: 'for'ce appli'e'liby the-pull Wire I50.

Thelnward move "ent'of the reset buttonit! is thus forced inwardly, aand-Js m to move the-diap ragm? Hill-arid cause movement of the auxiliary valve stem 96 axially against the bias of the coil spring 91"w hl'ch causes movement of the auxiliary valve member- 94 from its seat. Fuel 'isthus fpermitted to new from the pipe '18, inlet 80,- a-n'dl chamber fl 'through the a'p ertu'ies 98, outlet 92 and pipe 14 'f rIsUppIying the flash pilot burner 10 and the thermocouple heatingburner Hf2. 'Siinultaneously, ruei flows throughthe branc pipe 16- to the auxiliary pilot burner 1-2;" 9 I ing this'r'e'settin'g operation the stem 48 of the closure disc "42 is engagedb'y the cliaa phragm 84 a'nd is moved "against-the bias offthe spring 50 into engagement with the seat; The valve member 36 -is si'multaneous1y moved away from its seat 3'8,'bi.1t fuel is prevented-{from flowmg;- f rm the passage"32"throughthe outlet 3! tothe mai n burner I due to'theimmediate-seating of the closure disc 42. It may be noted that immediately prior to engagement of theclos'ure disc '42 with its seat '44 that the armature '66 has been 'pIaCed in contact with the pole faces of the horseshoe magnet 62. However, the closure disc reafte'r be 'iho ved into "engagement ea fl due to theprovision of the overwhic-h -isco" pressed during such urnei'WZnoW re'ce'ivinga tube I I8 causes ignition I v e constant burningtop pilot burner-1 2 Als "hefiash pilot burr- 16F and thermocouple Theater burner; H 2 'arerecei t hes T20 and 22 re pe tionpilot burner H 4 i's pr'ovide'd, this burner also Becomes ignited from "the thermocouple "heating burner-H2. A'fter a predetermined" time "delayfduring which 'th'e bime'ta'l' strip: 136 becomes-sufiiciently heated by the flame 'fro'm the auxiliary pilot burner 12,*the strip Twa'rpstari'd tri'ps'the latching element130. "warping ."of the bimetalstrip I36 causes the direction of lthe 'torque at the slot .t34 -to be ichanged from' 'xclockwi'se to counter-1 clockwise. 3Hence-,- the 'lat'ching element 130 is rotated;counterclockwise when tripped and will move'the bimetal strip ltfi-out of the flame-0f the auxiliary pilot burner-"J2- :to its initial cold position and: simultaneously relieve the force The-system isnow in its-steady'state operate ing zcondition. -'I he retraction of-the reset stem l-04"has caused the auxiliary yalve;-94 tQ-rbfi, moved under the bias of the spring 9 1 into-e11 easem nt w h. its; e t t pr v n w iofi'ju "est (m t the rel ase-movement'-befiw en iiig flier which is ignited by fme'ans of thefi sh? ct'i-i/ely. "Where the igni-f go the outlet-also :that the now of fuel through the pipe 14 tot-he flash pilot burner 10, thermocouple from sthe thermocouple heating burner I I2 and theeig'nition'. pilot burner H4 where used to generate .c'urrentcior energizing the electromagnet' before the auxiliary valve 94 is moved to closed position. the armature 661s now held'ln.

attracted position against the pole faces of the magnet 62, the valve member .36.. remains open while the closure disc 42 becomes. disengaged I from the seat 44-under=thebiasof the coil spring v 50; l 'l'olw of fuel fromfthe inlet '26, passage '32 and outlet- 34 to the main burner 10 is now perv-- mitted;v This burn'er is ignited by the flame at the ignitionipilot humor 1 M, or where the latter is idispensedwith by the flame at the thermo couple heating burner H2.

t It has been mentioned herein that the ignition pilot burner I I4 may be dispensed with if desired. It then becomes necessary for the thermocouple heating. burner I l 2 i to "be r positioned .to ignite the main burner-1031M. theflowof fuel t ithis burner. lilz is'cutlofi by closure of the auxiliary valve-94 when the resetting operation is completedva'nd the-closure disc has only at that time left its seat '44, his also necessary that the unconsumed 'fu'el remaining inpipe' T4 after the auxiliaryvalv'e 94 closes :be relied upon to continue the flame atithisbu'rner until the main burner is ignited'thereby. Moreover, after the thermocouple heatin'gburner H 2 ceases it will be'necessary "for the tnermocoupleto be heated by the name from the mai-n burner 1'0. An ad-. vantage ofthe arrangementis that a 10?) percent shut-cit of fuel :is'obtained upon operation'of the safety control.

Where the ignition pilot burner H4 is employed it is unnecessary to locate'the thermocouple M3" to be heated "by the main burner flame for torely upon residual fuel in pipe 14 to ignitethe main burner T0,: In this arrangement, however, a per cent shut-oil is not possible dueto the pipe -I IB being connected to pipe 18 ahead o 'f the control dev'ice 2'2. v r

i 'Iffatanytime during the operation of the apparatus the thermocouple I08 ceases to be heated by the fiamefrom the ignition pilot burn 1 er I l'4,'or' the main burner Ijfl'where the ignition its rbr'iginal ofi position upon-termination of the: ovensburner operation. During this returnmovement of the knob 21 the lug I68 will again passiurider the toothed portion 1 '6'6 but i'ri 'reyer'se direction dueto the :yieldable mounting of the slidable' member 162 on v"the bracket 154.

' .It' wil'lwbe apparent' that an automatic means of "resetting a ithermo'mag'netic safety device has been provided andis operable by 'nierely manipulating v the *usual knob of a; fuel cocl: from "as" tofon positions or to a desired temperature setting wherefa combined thermostat and fuel cockisiprovided. It will be apparent that .inany. changes; may be made the arrangement and combination of parts and in: the details of con-v situation shown; and described "within the. scope of the .appended claims without departure from the spirit of the invention.

position, means adapted to be responsive to a flame at the pilot burner for energizing said electromagnetic means, resetting means movable to an operative position for positioning said safety control device in said flow permitting position,"and a thermal timing device operably associated with said resetting means for returning said resetting means to an inoperative position after a predetermined period following ignition of the fuel at the pilot burner during which period said flame responsive means has had time to energize said electromagnetic means.

2. Safety control apparatus for a fuel burning appliance having main and pilot burners and a source'of fuel supply, comprising main control meansoperable between closed and open positions for controlling the flow of fuel from the source to the burners, a safety control device movable between positions and adapted for respe'ctively preventing and permitting flow of fuel from said main control means to at least the main burner while said main control means is in said open position, said safety control device being biased to said flow preventing position, electromagnetic means adapted. whenenergized to hold said safety control device in said flow permitting position, means adapted to be responsive to a flame at the pilot burner for energizing said I electromagnetic means, resetting means movable by the opening operation of said main control means to an operative position for causingmovement of said safety control device to its flow permitting position, heating means controlled by said main control means, and a thermal timing device forming part of said resetting means and being responsive to said heating means for returning said resetting means to an inoperative position when said heating means has operated for a predetermined period during which said flame responsive means has had time to energize said electromagnetic means.

' 3. Safetycontrol apparatus fora fuel burning appliance having main, auxiliary and pilot burners and-a-souroe of fuel supply, comprising main control means operable between closed and open positions-for controlling the flow of fuel from the source to the burners, a safety control device movable between positions and adapted for respectively preventing and permitting flow of fuel from said main control means to at least the main burner while said main control means is in said open position, said safety control device being biased to said flow preventing position, electromagnetic means adapted when energized to hold said safety control device in said flow permitting position, means adapted to be re sponsive to a flame at the pilot burner for energizing said electromagnetic means, resetting meansmovable by the opening operation of said main control means to an operative position for causingmovement of said safety control device toits flow :permitting position, and a thermal timing device forming part of said resetting means and beingadapted to be responsivetoa flame at the auxiliary burner for returning said resetting means to an inoperative position after a predetermined period during which said flame responsive means has had time to energize said electromagnetic means. a g

4. Safety control apparatus for a fuel burning appliance having main, auxiliary and pilot burners and a source of fuel supply, comprising main control means operable between closed and open positions for controlling the flow .of fuel from the source to the burners, a safety control device movable between positions and adapted for respectively preventing and permitting flow of fuel from said main control means to at least the main burner while said main controlmeans is in said open position, said safety control device being biased to said flow preventing position, electromagnetic means adapted when energized to hold said'safety control device in saiddlow permitting position, a thermoelectric generator adapted to be responsive to a flame at the pilot bumerfor energizing said electromagneticmeans, resetting means movable by the opening. operation of said main control means to an operative position for causing movement of said safetygcontrol device to its flow permitting position, said resetting means including a latch movable,,to, a latching position by the opening operation of said main control means for retaining said safety control device in said flow permittingposition, and a device adapted to be responsive to a flame at the auxiliary burner for releasing saidlatch after a predetermined period during'which said thermoelectricgenerator has had time to energize said electromagnetic'means. p j

5. Safety control apparatus as claimed in claim 4 wherein said flame responsive device comprises a bimetal element forming partof saidlatch andbeing adapted to warp upon heating for said pre-' determined period, said latch being biased for, return to an inoperative position when said himetal element becomes warped.

6. Safety control apparatus for a fuel burning appliance having main, auxiliary and pilot burners and a source of-fuel supply, comprising main control means operable betweenclosed and open positions for controlling the flow of fuel from, the source to the burners, a safety control device movable between positions and adapted'for' respectively preventing and permitting flow of fuel from said main control means to at least the main burner while said main control means is in said open position, said safety control device being biased to said flow preventing position, electromagnetic means adapted when energizedto hold said safety control device in said flow permitting position, means adapted to be responsive to a flame at the pilot burner for energizing said electromagnetic means, resetting means movable to an operative position for causing movement of said safety control device to its flow permitting position, connecting means between said main control means and said resetting means for transmitting movement to said resetting means, and thermal timing means adapted to be responsive to a flame at the auxiliary burner for rendering said connecting means ineffective after a predetermined period during which said flame responsive means has had time to energize said electromagnetic means.

7. Safety control apparatus as claimed in claim 6 wherein said resetting means includes a latch movable to latching position by said connecting element being adapted to be warpedby said flame for moving out" of said path and simultaneously releasing said latch while 'said main control means remain. in saidbpen position. '8 Safety control; apparatus -'forafuel burning appliance having main, auxiliary and pilot burners--and-a source-oi fuel supply, comprising a safety; control device movable between positions and'ndapted for respectively preventing and permitting flow of fuel from the source'to at least the-main burner, said safety control device being biased to said flow preventing position, electromagnetic means-adapted when energized to hold said safety control device in said flow permitting position, a thermoelectricgenerator adaptedto 'be heated by' a'fiameat the pilot burner forener- 'g'i'zing said electromagnetic means, an auxiliary control device movablebetween positions and adapted for respectively preventing and permitting-flow of fuel from the source to said auxiliary and-pilot burners and being biased'to said flow preventing position, resetting means movable to operative position for ca'usingmovementof said safety control'device and said auxiliarycontrol device to said flow permitting positions, means oper-atively associated with said resetting 'mea'ns' for interrupting the flow of rfuel to the main burner during said resetting operation,

and means including a device responsive to -a flame at the auxiliary 'burner for rendering said resetting means inoperative after apredetermined period during which said thermoelectric generator has time to'become heated and causing v said auxiliary control-ldevice-to move to said flow preventing position while said safety control device 'is'held in said flow permittingposition.

9. Safety control apparatus-as claimed in claim Swherein an ignition pilot burner is-adapted to receive fuel from the source and bypassing said auxiliary control device, said thermoelectric generator being adapted to-be heated by a flame- "at the ignition pilot burner after said'auxiliary control device has moved to said flow preventing position. V

10. Safety control apparatus for a fuelburning'appliance having main, auxiliary and pilot ,e'rsand ,a source of fuel supply, comprising fety control device movable between posiy no 5 and adapted for respectively preventing and permitting flow of fuel from the-source to v at least the main burner, saidsafetycontrol device being biased to said'flow preventing position,- electromagnetic means adapted when energized to hold said safetycontrol device insaid I flow permitting position, a thermoelectric generator adapted to be-heated by a flame at the pilot burner for energizing said electromagnetic means, an auxiliary control device havinglostmotion connection with'said safety control devicexand being adapted for respectively preventing and permittingfiow of fuel from the source to said auxiliary and pilot burners, said auxiliary control device being biased to'said flow preventing position, resetting means movable to an operative position for'causing movement of said safety control device and said auxiliary control device to said flow permitting positions,

means operatively associated with said resetting meansfor interrupting the fl'ow of fuel to the main burner durin ithelresetting; operation, and means responsive toiias fiame.:at therauxiliary burner for rendering said resetting means inoperative after a predeterminedsperiod. during which said thermoelectric generator has time'to become heated and causing said auxiliary control device to move to said flow preventing position'. while said safety control devicev is held in said fl'ow permitting position.

11. A safety control and. ignition. apparatus for a fuel burning appliance comprising incombination, a main burner; afuel supply pipe connected to said main..burner,. means for ignitin said main burner .includinga pilotv burner: in proximity ofithe' main. burner .andihaving separate connection with; said. fuel supply pipe, a constant burning pilotzburner positioned remote from, the; first .saidllpilot; burner; a flash-tube assembly extending between said-pilot burners for conducting a flame 'therebetween, an auxiliarly i pilot burner; in proximity ,of said constant burningv pilot burner: and: adapted for receiving a supply ofi fuel from said :separateconnection, arsaf'etyxcontrol. device movable between positions for controlling the supply of fuel to at least the main burner, said safety control device being biased to a position for preventing said fuel supply, electromagnetic means adapted when energized to hold said safety control device in a. flow permittin position, a thermoelectric generator adapted to be heated bya flame at said first pilot burner for energizing 'said electromagnetic means, resetting means operable for positioning saidasafet y control device in said. flow permitting position, and timing meansioperatively associated with said resetting meansiandzbeing responsive to a flame at said auxiliary burner: for. returningsaid resetting means'to. an inoperativeposition after a predetermined period during which said thermoelectric generator hasi'ti'meto become heated.

l2.;.Safety control and ignition apparatus as claimed inclaim 11 wherein said safety control device includes means for controlling. the supply of fllBIl to said first and-auxiliary pilot burners independently of said main burner fuel supply, said timing .means being. effective for causin movement of said safety control device to a position where fuel supply to. the first andlauxiliary pilotburners is preventedand fuel supply to the maintburner is continued.

13. Safety control and ignition apparatus as claimed in claim 12 wherein said] first pilot burner comprises a heater burner for said thermoelectric generator, and an ignition pilot burner adapted to receive a supply of fuel from said separate connection but bypassing said safety c0ntro1 device, said thermoelectric generator beingadapted to be heated by a flame at said ignition pilot burnerafter said safety control device has prevented the fuel supply to said first pilot burner.

CHARLES'K. STROBEL. STANLEY J LAKOTA.

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

UNITED STATES PATENTS Number Name Date" 2,257,927 Wunsch 'et a1. Oct. 7, 1941 2,290,048 Hilde-Brecht July 14, 1942 2,340,234 Thornbery et al. Jan. 25, 1944 2,351,277 Mantz a June 13, 1944