US2637391A

US2637391A - Automatic ignition and control mechanism for oven burners

Info

Publication number: US2637391A
Application number: US269356A
Authority: US
Inventors: Richard L Perl; John M Hoff
Original assignee: TAPPAN STOVE CO
Current assignee: TAPPAN STOVE Co
Priority date: 1952-02-01
Filing date: 1952-02-01
Publication date: 1953-05-05
Anticipated expiration: 1970-05-05

Description

May 5, 1953 R. L. PERL ET AL 2,637,391

AUTOMATIC IGNITION AND CONTROL MECHANISM FOR OVEN BURNERS Filed Feb. 1, 1952 4 Sheets-Sheet l INVENTORS Flo/7am? L. Per/ BY 8 J0/1/1 M Hoff May 5, 1953 R. L. PERL ETAL 2,637,391

' AUTOMATIC IGNITION AND CONTROL MECHANISM FOR OVEN BURNERS Filed Feb. 1, 1953 v 4 Sheets-Sheet 2 3 Jay? 35 4 5-;

0 INVENTORS Richard L Perl r" 7 5 BY 9J0/7/1 Mfioff May 5,1953. R. L. PERL ET AL 2,637,391

AUTOMATIC IGNITION AND CONTROLMECHANISM FOR OVEN BURNERS Filed F'eb. .'l., 1952 4 Sheets-Sheet 5 LINE 91a Q g /0, M I /3 1C a/" l BY flJohnMHoff yjwgg May 5, 1953 R. L. PERL ETAL 2,637,391

AUTOMATIC IGNITION AND CONTROL MECHANISM FOR OVEN BURNERS Filed Feb. J., 1952 4 Sheets-Sheet 4 u I INVENTORS Richard .4. Perl BY @Hfo/vn N; Ho f7 5644. A4]M% fifty;

Patented May 5, 1953 AUTOMATIG IGNITION AND-CONTROL MECHANISM FOR BUBNERS' Rich Ije l, Galina m! J hn H ff. a s:

Ohio

Applieeti n 9.5.2 Ser laNm 269,356.:

T is invent-inn elat s t an utome e elect ie i n ti n an eoett l 'mephen' n mm e mneebqnners, g gaseous f e1 'ngiij m t a pn 9 the qt q mesh-: 1 endinsap Qhn. eft le l l- 3, 0',

lfifififie, 0W e e -END, 2,51 7 e pec designed and adapter; for em't'pmgfiiflal and cqnfiro lix the @p re me e We eaot e ran es, may be u H with a time control meeheiqism or epenq ,1 thereof- .as sies lt d p nanism is designed, er use with a v w s-rw 'm is m me-QM b i n t d by a g e us in. pilqt umen A 9% as t e p qt burne is ignite it s. imm eria Whe he or n t, the te We l r bur s Qwstantly. It may be extin shed for sogr reason, but it will be erempt r e-ie ited b mei burner i iel s su pl ed ihe em But f; the p lot w 'ne s extineuisnesi i-Qi reas n Wh le the. cent sal eis. s i pen t $1 99. 3? 9 the burne a ve y dansetqu e tuetien sometimes arises. Let us assume that both the in the even wh m, viii? i :i

attem t is me e to 1 be ethe th mai or. pilot burner. It has been found p ireq e tit n ufl shed Queue @nemtim T s is somet mes. ie. t mome a y $79 1 I the g s su ly or t e slamm n oi theevendee to ver es ether lieasens.

o de t pnewient a wm l t nh 91-? i EKQlQSiQ- th r fro in t e is extinguished for any reg u I We emt de n 9 .11 m n we a pa atu a eai eentm unit y wi sup ly Qf' gas to b th the urner and he pilet b ner 1s 9.

2 qeols erange is h e d- Th m n we r s elem d we ii; ited by e ase s iue Pilot eumef h ums 0.1. 12 de e he time the ev is i p r ti n-- Moth times t e uppl T 5 t9- b th h ma n u nez and the pilot is cu off-. tpesaf W c nt/ eel un Whi-Qh q i it etwe nth eeesum xain b ner. Du ing 09. 2% 0 r m; the memim mm ie t mm he a e :19: s

m br mk QQIIQUUZGBZGOD o r o v eml lir ueht be ma onduit and steward e m te eel e weeed e n wi m tur cont l l e s h einhu ner A en ma t iro i' w tp i m qeq ts: o erat n or bfl h he l t burne a the. m; n buir r The c b iine- Qt, t e master q t'ql. 'w h' ne ei ee thr h: t ravine 4 v ceilses lit q lsettlieseiety roltun t s autcm a lye-M spewing 111 ns ppl i a s qthem wen: e lee a' e qmm t ttle. line burner i the gnit d by the-p lotuburnt rh he twing -9111 7 s q $5 st e m 13h rner meme-1m n uehi he e ve-ma n n we s tqih tlqi eme nihumor Th ev t mee z c mel, va then egulates the, sup 1x ofv gas qthe 1p in burne w meinta' nthe' e iri dhqven t H 11. 1 1 is gn te m; m sh-fi m r ill bu ne y en r, he

oi t e v wem m t t qu f ng vdperationithe b e 4 had, e r nt re 9 kt mer time i x nn rpl pemtilte, long astl As an example of the manner of operation of the apparatus, let us assume that during operation the pilot burner is suddenly extinguished, for instance, by a momentary failure of the gas supply from the manifold to the burners. The thermocouple immediately cools, allowing the safety control unit to cut off communication between the manifold and both the main burner and the pilot burner. Then after the thermostatic element has cooled, closing the normally closed switch, which is maintained open by the thermostatic element during normal operation of the oven, the electric ignition element and the solenoid transformer are again energized, since the master control switch is still closed. The energization of the solenoid transformer will cause it to operate the safety control unit to establish communication between the manifold and the pilot burner only. Then when gas is again available the pilot burner will be re-ignited and re-establish normal operation of the oven as previously described. In the event of a power failure during normal operation of the oven, the main burner will continue to operate normally under the control of the oven temperature regulator valve until the operation of the burner is terminated, assuming of course that the pilot burner continues to burn. In the event of a power failure before gas is turned on to initiate operation, the pilot burner can be manually ignited as will be hereinafter explained. The supply of gas to both the main burner and the pilot burner will then be controlled by the pilot burner through the thermocouple and safety control valve mechanism as previously described.

In order to extinguish the pilot burner and the main burner to terminate operation we provide an interrupter switch in the circuit between the thermocouple and the safety control unit.

This switch is located in the same casing as the master control switch and is opened and closed in unison with the opening and closing of the master control switch. Then when the interrupter switch is opened the circuit between the thermocouple and the safety control unit is broken which permits the safety control unit to cut off the supply of gas to both the pilot burner and the main burner and thus terminate operation.

When it is desired to use the apparatus in conjunction with any standard time control mechanism, we provide a normally open supplemental master switch and a normally open supplemental interrupter switch. The supplemental master switch is interposed in the solenoid transformer circuit in a by-pass around the master switch, and the supplemental interrupter switch is interposed in the thermocouple circuit in parallel with the interrupter switch. The supplemental master switch is adapted to be opened and closed at predetermined set times by the time control mechanism and the supplemental interrupter switch is adapted to be closed by a relay which is energized by the closing of the supplemental master switch. When used the time control mechanism is set to initiate operation of the oven burner at a predetermined time and to terminate operation thereof at a predetermined later time. At the set time the time control mechanism will close the normally open supplemental master switch which will effect the closing of the supplemental interrupter switch and the energization of the solenoid transformer and the electric ignition element. The apparatus will then operate as previously described in connection with manual control until the time control mechanism opens the supplemental master switch at the set later time to terminate operation. The opening of the supplemental master switch will effect the opening of the supplemental interrupter switch which will open the thermocouple circuit and allow the safety control unit to out off the supply of gas to both the main burner and the pilot burner, thus terminating operation.

Prolonged power failures of many hours and sometimes of even several days duration frequently occur in various different parts of the country. In order to eliminate the necessity of either keeping the main burner burning constantly during a prolonged power failure or manually actuating the safety control unit, as is normally done by the solenoid transformer, and then lighting the pilot burner with a match, we provide means by which the pilot burner may be arranged to burn constantly instead of being extinguished each time the supply of gas to the main burner is cut off. We also provide means by which the safety control unit may be manually actuated to admit gas to the main burner to initiate operation thereof, and to cut off the supply of gas thereto to terminate operation thereof.

The principal object of the invention is to provide an improved electrical ignition and automatic control system for cooking range oven burners using gaseous fuel.

Another object of the invention is to provide in an electrical ignition and control system of the character described improved means for completely shutting off the supply of gas to both the main burner and the pilot burner in the event the pilot burner becomes extinguished for any reason during operation.

be set for manual control during prolonged power failure.

Still another object of the invention is to provide an improved electrical ignition and control system of the character described which may be used in conjunction with a time control mechanism or independently thereof as desired.

Other and more limited objects of the invention will be apparent from the following specification and the accompanying drawing forming a part thereof, wherein:

Fig. 1 is a diagrammatic layout showing our improved electrical ignition and safety control mechanism applied to a cooking range oven burner using gaseous fuel;

Fig. 2 is an enlarged central vertical section through the safety control unit showing the various parts in position to cut off the supply of .fuel to both the pilot burner and the main burner;

Fig. 3 is a view similar to Fig. 2 showing the various parts in the positions they are automatically moved to when the master control :switch is closed to initiate the operation of the :main oven burner;

Fig. 4 is a wiring diagram showing the switches and the main control valve in off posi tiori;

Fig. is a detail sectionai view showing the apparatus set for manual control; and

Fig. 6 is a View similar to Fig. 1 showing'a slightly modified form of the invention.

Referring now to the drawings by reference characters, the numeral indicates a gaseous fuel burner which is mounted in or ih heating relation to a cooking range oven 2. Gaseous fuelis supplied to the burner I from a manifold M through a conduit 3. Interposed in the coil-'- duit 3 are a safety control valve mechanism generally indicated by the numeral 4, and an oven temperature control valve 5. During op eration gas flows from the manifold M through the conduit 3 to the safety control unit 4 to be described in detail hereinafter.- From the safety control unit 4 the gas flows through the conduit 5, and the oven temperature control valve 5 to the burner l. The oven temperature control valve 5 is operative to regulate the amount of gas flowing to the burner in order to maintain the oven 2 at any desired set temperature. The valve 5 is set to any desired temperature by a handle 6 having a pointer 1 which cooperates with a graduated dial 8 carried by the valve 5. The valve 5 is controlled according to the teinperature setting by a thermostatic element 9 which is mounted in the oven 2 and is connected to the valve 5 as shown at it. The oven temperature control valve 5 is of standard well known construction. Consequently itis not shown in detail herein. There are many different constructions available any one of which will work equally well herein. Gas is also supplied to a pilot burner through a branch conduit |2 which extends between the safety control valve mechanism 4 and the pilot burner I The pilot burner II is disposed adjacent the rear end of the main burner in position to ignite the burner I when gas is supplied thereto. An electrical ignition element I3 is operatively associated with the pilot burner II in position to ignite the pilot burner II when gas is supplied thereto. A thermostatic element l4 and a multiple thermocouple l5 are mounted in position to be heated by a flame from the pilot burner. The thenfiostatic element I4 is operative to open and close a switch It which controls the-energization of the electrical ignition element l3 and a solenoid transformer i! which when energized-operates the safety control unit to supply gas to the pilot burner only as will be described in connection with the description of the safety control unit and the operation of the'whole apparatus. The thermocouple 55, when heated. is operative to hold the safety control unitin condition to maintain the supply of gas to both the pilot burner H and the main burner I, as will also be described in connection with'the description of the safety control valve mechanism and'the operation of the apparatus.

A master control switch i8 is provided to initiate operation of the burner l, and an interrupter switch 19 is provided to terminate operation thereof. The switches I8 and ii! are mounted in a case 25) secured to an accessible panel 2| mounted on the range and are opened and closed in unison by a switch stem '22 and a switch handle 23.

An electric circuit between the thermocouple l5 and the safety control unit '4 is established by a copper tube 24 'whichencloses an insulated aeeasoi wire 25. The wire is severed between the thermocouple l5 and the safety control unit' 4 and an'interrupter 26 having

terminals

21 and 23 is interrupted between the several ends. One of the severed ends of the wire 25 is connected to the terminal 21 and the other severed end is connected to the'terminal 28. The purpose of the interru ter 26 will be explained in detail-in connection with the description of the operation or the apparatus.

The construction of the safety control 4 and its connection to the solenoid transformer I1 will now be described, reference being had to Figs. 2 alld'3, or the drawings. This unit oompriscs a casing having a chamber 36 in one end thereof and a chamber 3 in the other end thereof. The chambers 36 and 31 are'connected by a bore 38 of reduced diameter. A valve" seat 39 is located at one end of the bore 38 audasimilar valve seat 40 is located at theother end of the bore 38'.- The chamber 36 is closed by a removable cap 4| and the chamber 31 is closed by a removable can 42. A sleeve 43, having end walls 44 and 45, is carried by the cap 4| and extends into the chamber 36. A valve stem '46 which is slidaloly mounted in a bushing 4'! carried by the end wall 45 of the sleeve, extends from the chamber 36 into the sleeve 43. A control valve 48- of suitable material is secured to one end of the valve stem within the chainber 36, and an armature 49 is secured to the other cixd'of the stem #5 Within the sleeve 43. A spring disposed about the valve stein 46 between the control valve 48 and the end wall 45 of the sleeve 43 normally holds the control valve 48 against the valve seat 39. An electromagnet 5| is secured to one end of a hollow cXtcr'iorly threaded Stud 52 which extends out through aligned apertures in the end wall 44, of the sleeve 43, and in the end of the cap 4|. A nut 53 screwed onto the outer portion of the stud'52 securely holds the magnet 5| and the sleeve 43 in place. The legs of the magnet 5| have a Winding 54 thereon. one end of which is connected to the tube 24 and the other end of which is connected to the wire 25 in the tube 24. The tube 24 is inserted into-the hollow stud- 52 and is held in place by a screw fitting 52 a. A sleeve 55 is' screwed into a threaded recess in the end of the cap 42,'a's indicated at 56, and extends into the chamber 31 'a. Slight distance. One end of the sleeve" '55 is closed by an end wall 51, and the other end, which is open, registers with a cicular a erture 58 in the end wall of the cap 42. A plunger 59 is slidably mounted in the sleeve 55 and extends out through the aperture '58 in the cap 42. A stem :62. which is secured to the inner end of the plunger 59, extends out through an aperture'ts in theend wall 51 of the sleeve 55, and through the chamber 31 and into the bore '38. The stem-52 has acollar 64 rigidly secured thereon between the end 5! and the outer end of the stem. interrupter valve of suitable material is sl-idahl'y mounted upon the stem 62 between the end wall 57 of the sleeve 55 and the collar 64 The interrupter valve t5 is adapted to engage the valve seat 40 to cutoff the flowof gas intothe chamber 31 during the initiation of operation as will be hereinafter described. A compression spring 56 disposed about the stem 62 between the end'wall 51 and the valve '65 normally yieldingly holds the valve 65 against the collar 54. A compression spring 5'! which is stronger than the spring- 66 is disposed about the stem "62 within the sleeve {55 between the inner face of the end wall 57 and the stationary contact 84.

7. the inner end of the plunger 59. The spring 61 is operative to return the plunger 59, stem 62 and valve 65 from the position shown in Fig. 3 back to their normal position as shown in Fig. 2, against the resistance of the spring 66. A port 68 in the casing 35 provides communication between the chamber 3 6 and the conduit 3 to allow gas to flow from the manifold M through the conduit 3 into the chamber 36. During normal operation'of the main burner I gas flows from the chamber'36 through the reduced intermediate bore 38 and into the chamber 31. A port 69 which establishes communication between the branch conduit I2 and the bore 38 is provided to supply gas to the pilot burner II; and a port 18 establishes communication between the chamber 31 and the conduit 3 to permit the flow of gas from the chamber 31 to the main burner I through the oven temperature control valve 5.

The solenoid transformer I1 comprises a spool I5 on which are wound the primary winding 16 and the secondary winding 11. An armature I8 :Of the safety control unit 4.

The master control switch I8 comprises the arm 8| and the stationary contact 82; and the interrupter switch I9 comprises the arm 83 and The contacts 82 and 84 are suitably secured to the casing 20. The arms 8| and 83 are rigidly secured to the stem 22 for rotation therewith so that the switches I8 and I9 are opened and closed in unison when the stem 22 is rotated by the switch handle 23.

In order to accommodate the apparatus for automatic control whereby operation of the main oven burner I may be automatically initiated at a predetermined set time and automatically terminated atfla predetermined set later time, we

provide a normally open supplemental master switch 85 and a normally open supplemental interrupter switch 86. The supplemental master switch 85 is adapted to be closed and opened by a standard time control mechanism 81; and the supplemental interrupter switch 86 is adapted to be closed by a relay 88 which is energized by the closing of the supplemental master switch 85.

p The operation of the apparatus will now be described, particular reference being had to Fig. 4 of the drawings. For manual control it is only necessary to close the master switch I8 and the interrupter switch I9 to initiate operation, and then open these switches to terminate operation. When the switches I8 and I9 are closed current will flow from one side 98 of the line through the lead 9| to the contact 82 of the switch I8, thence through the switch arm BI and lead 92 to the normally closed thermally open switch I6. The current then flows through the switch I6 and lead 93 to the primar winding 16 of the solenoid transformer I1 and from there back to the other side 84 of the line through the lead 95. The solenoid transformer I1 is now energized, and the electric ignition element I3, which is connected to the secondary winding 11 of the solenoid transformer by the leads 96 and 91 is also energized. The solenoid transformer I1 being energized shifts the various parts of the safety control unit from the positions shown in Fig. 2 to the position shown in Fig. 3. Gas

can now flow to the pilot burner II where it is ignited by the ignition element I3, but it cannot yet flow to the main burner I since the interrupter valve mechanism in the chamber 31 of the safety control unit is maintaining the entrance thereto closed. The pilot burner being ignited heats the thermocouple I5 and the thermal element I4. The thermocouple being heated generates a minute current of the order of 200 to 250 millivolts which flows from the thermocouple through the tube 24 to the winding 54 of the electromagnet 5I and from there through the wire 25 to the terminal 21 of the interrupter 26. From the terminal 21 the current flows through the lead 98, contact 82, switch arm BI and lead 99 to the terminal 28 of the interrupter 26, and from there back to the thermocouple I5 through the wire 25. The thermocouple current energizes the electromagnet 6I sufliciently for it to hold the control valve mechanism in the chamber 36 in the position shown in Fig. 3 after it. has been moved to this position by the solenoid transformer I1, but not enough for the electromagnet to attract the mechanism from the position shown in Fig. 2 to the position shown in Fig. 3. The heating of the thermal element I4 causes it to open the normally closed switch I6 which breaks the circuit to and de-energizes the solenoid I1 and consequently the ignition element I3. As soon as the solenoid transformer I1 is de-energized the spring 61 returns the interrupter valve mechanism in the chamber 31 back from the position shown in Fig. 3 to the position shown in Fig. 2 while the electromagnet 5| holds the control valve mechanism in the chamber 36 in the position shown in Fig. 3. Gas can now flow to the main burner I where it is ignited by the pilot burner II. Under normal conditions the burner I will now operate under control of the oven temperature control valve 5 until its operation is terminated by the opening of the switches I8 and I9. The opening of the interrupter switch I9 breaks the thermocouple circuit and de-energizes the electromagnet 5| after which the spring 50 returns the control valve mechanism in the chamber 36 back from the position shown in Fig. 3 to the position shown in Fig. 2, thus cutting off the supply of gas to both the main burner and the pilot burner. If the pilot burner is extinguished for any reason during operation, then the thermocouple I5 and the thermal element I4 will cool. The electromagnet 5I will then be de-energized and release the control valve mechanism in the chamber 36 which will then be returned by the spring 50 to the position shown in Fig. 2 cutting off the supply of gas to both the pilot burner II and the main burner I. When the thermal element I4 cools, which is after the thermocouple I5 has cooled, the switch I6 will close. The apparatus will then re-cycle as described as soon as gas is available.

The supplemental interrupter 86 is interposed in the thermocouple circuit in series with the interrupter switch I9 by the leads I00 and IIJI which are connected to the leads 98 and 99 respectively. The supplemental interrupter switch 86 is necessary to adapt the apparatus for automatic control, but it performs no useful function when the apparatus is used under manual control. Nevertheless the interrupter switch 86 is always closed and opened by the closing and opening of the master switch I8 through the medium of the relay 88 which is interposed between the leads 92 and 95 by the leads I02 and I03 which by-pass the switch It and the primary winding 16 of the solenoid transformer I]. As long as the master switch is closed, current will flow from the side 90 of the line through the lead 91, switch l8, lead 92, lead I02, relay 93, lead I03 and back to the otherside 94 of the line through the lead 95, thus energizing the relay 88 and holding the switch 813 closed. As soon as the master switch I8 is opened the relay 88 will be de-energized which will allow the switch 89 to return to its normal open position.

For automatic operation the switches I8 and I9 are left open and the time control mechanism 01 is set to initiate operation at the desired time and to terminate operation at the desired later time. At the set time the time control mecha-- nism 81 will close the supplemental master switch 85 which is interposed between the leads I04 and I05 which connect the lead 9| to the lead 92 and by-pass the switch I9. Current will then flow from the side 90 of the line through the leads 9| and I04, switch 85, leads I05 and 92, switch I6, and lead 93 to the primary winding of the solenoid transformer I1, and from there back to the other side 94 of the line through the lead 95. Current will also flow from the lead 92 through the lead I02, relay 98 and leads I93 and 95 to the side 94 of the line. former IT and the electric ignition element H are now energized, and the supplemental interrupter switch 86 is closed. The solenoid transformer II, being energized will shift the interrupter valve mechanism and the control valve the tube 24 to the winding 54 of the electromagnet SI and back to the thermocouple I5 through the wire 25, leads 98 and NI, interrupter switch 80, leads WI and 99, and wire 25, thus energizing the electromagnet 5I. The heating of the thermostatic element I4 will open the normally closed switch I9 and de-energize the solenoid transformer IT and electric ignition element I3. The

spring 6! then returns the interrupter I valve mechanism in the chamber 3! back from the positionshown in Fig. 3 to the position shown in Fig.

2 while the electromagnet 5I retains the control valve mechanism in the chamber 39 in the position shown in Fig. 3. Gas will now flow to the main burner I which is then ignited by the pilot burner I i. The burner I will now operate under the control of the pilot burner II and the oven temperature control valve 5 until the operation thereof is terminated by the time control mechanism 8'! opening the switch 85. The openin of the switch 85 de-energizes the relay 98 which effects the opening of the switch 86. The opening of the switch 86 breaks the circuit to and deenergizes the electromagnet 93 which allows the spring 50 to return the control valve mechanism in the chamber back from the open position shown in Fig. 3 to the closed position shown in Fig. 2, thus cutting off the supply of gas to'both the pilot burner II and the main burner and terminating operation.

'In order that the oven may be repeatedly The solenoid trans- 10 used during a prolonged power failure without the necessity of manually lighting the pilot burner II with a match each time it is used, we have provided means by which the apparatus canbe quickly and easily converted from a fully automatic electric ignition system to a constantly burning pilot burner ignition system. To this end we provide a plunger H0 which is slidably mounted in a sleeve III carried by the panel 2| in axial alignment with the armature Iii of the solenoid transformer I1 and the plunger 59 of the safety control unit 4. The outer end of the plunger H0 is provided with an actuating knob H2 and a compression spring H3, stronger than F the combined strength of the springs 59, 99 and 61 in the control unit 4, is mounted in and extends out from an axial bore H4 in the inner end of the plunger H0. A pin H5 is carried by the plunger H0 and extends into an elongated slot H6 in the sleeve iii. In order to convert the apparatus to a constantly burning pilot burner system it is only necessary to close the interrupter switch I9 in the thermocouple circuit and manually depress the plunger H0 and lock it in depressed position by rotating it a few degrees until the pin H5 engages behind the panel 29 as shown in Fig. 5. The depressing and locking of the plunger H0 depresses the armature '79 of the solenoid transformer I! and the plunger 59 of the safety control unit 4 and sets and holds the safety control unit 4 as shown in Fig. 3. Gas can now flow to the pilot burner II, but is cut off from the main burner l by the interrupter valve 65. The pilot burner II is then ignited with a match. Under normal conditions it will now burn constantly and maintain the thermocouple I5 heated which will in turn maintain the electromagnet 5| energized. To initiate operation of the burner I under these conditions it is only necessary to unlock the plunger H0 by rotating it until the pin registers with the slot H6. The spring 61 will then open the interrupter valve 65 and return the plungers 59 and H0 and the armature I8 to their original positions as shown in Figs. 1 and 2. The electromagnet 5I retains the control valve 99 open as shown in Fig. 3. Gas can now flow to the main burner l and be ignited by the pilot burner H. To terminate operation the plunger H0 is depressed and locked which closes the interrupter valve 65 and cuts off the supply of gas to the main burner I while maintaining the control valve 48 open to supply gas to the pilot burner If the pilot burner II is extinguished for any reason during operation of the main burner I under these conditions, the control valve 40 will close and cut off the supply of gas to both the main burner and the pilot burner as explained in connection with electric i nition.

When power is again available the switch I 9 is opened and the plunger I I0 released; The opening of the switch I9 breaks the thermocouple circuit which allows the control valve 49 to close r' and cut off the supply of gas to and extinguish the pilot burner i l. The apparatus is then re-set for full automatic operation.

From the foregoing it will be seen that We have provided an automatic ignition and control ap paratus for gaseous fuel oven burners in which all manually operable shut off valves in the fuel supply conduit have been eliminated and that we use the automatically actuated safety control valve mechanism 4 both as a safety control valve during operation and as a cut off valve when the burner I is not being used. It will also be seen that the operation of the apparatus is primarily under the control of the master control switch I8 and the interrupter switch I9 which are opened and closed in unison with each other. The closing of these switches initiates operation of the burner I and the opening of these switches terminates operation thereof. During operation the apparatus is automatically controlled by the pilot burner II and the safety control valve mechanism 4. If during operation the pilot burner II is extinguished for any reason the safety control valve mechanism 4 will promptly cut off the supply of gas to both the pilot burner I I and the main burner I, and will maintain it cut off to the main burner I until the pilot burner has been re-ignited.

It will also be seen that we have provided very simple means by which the apparatus can be quickly and easily converted to a constantly burning pilot burner system if desired during prolonged power failures.

In Fig. 6 we have shown a slightly different means for converting the system from a fully automatic ignition system to a constantly burning pilot burner system during prolonged power failures. In this form of the invention we interpose a manually operable shut off valve 4a in the conduit 3 between the safety control unit 4 and the oven temperature control valve 5; and we eliminate the man ally actuable setting and looking mechanisms IIO to H6 and substitute therefor a plunger I20 which is slidably mounted in a sleeve I2I carried by the panel 2| in axial alignment with the armature I8 of the solenoid transformer I1 and the plunger 59 of the safety control unit 4. Otherwise the form of the invention is identical with that shown in Fig. 1 and the same reference numerals are applied to like parts.

During normal operation of this form of the invention with power available the valve 4a is left open and the apparatus functions exactly as described in connection with Fig. 1. In order to convert this form of the invention to a constantly burning pilot burner system during a prolonged power failure the manually operable valve 4a in the conduit 3 and the interrupter switch IS in the thermocouple circuit are closed. The plunger I20 is then depressed and a lighted match applied to the pilot burner I I. The depressin of the plun er I I opens the control valve 48 in the chamber 36 of the control unit 4 which permits the flow of Fas to the pilot burner II which is then ignited by the match. The pl n er I20 must be held depressed until the pilot burner II heats the thermocouple I5 snfficiently for it to energize the electromagnet 5|, after which the p unger I20 may be released. The electromagnet 5I being energized will now hold the control valve 48 in open position so that the pilot burner I I will burn constantly under normal conditions. Then in order to initiate operation of the main burner I it is only necessary to manually open the shut off valve 4a; and to terminate operation thereof the shut off valve 4a is turned to closed position. After power is again available the shut off valve 4a and the interrupter switch I9 are opened which re-sets the apparatus for fully automatic operation as described in connection with Fig. 1.

It is to be understood that we are not limited to the specific construction shown and described herein as various modifications may be made therein within the scope of the appended claims;

What is claimed is:

1. In an automatic ignition and control apparatus of the character described the combination of a main burner, a pilot burner operative to ignite said main burner, an electric ignition element operative when energized to ignite said pilot burner, a gaseous fuel supply manifold, a main conduit through which fuel is supplied to said main burner from said manifold, a safety control unit operative to cut off the supply of fuel to said main burner and said pilot burner interposed in said conduit between said main burner and said manifold, a branch conduit extending between said safety control unit and said pilot burner through which fuel is supplied to said pilot burner, a solenoid operatively associated with said safety control unit, said solenoid being operative upon energization to first set said safety control unit in condition to supply fuel to said pilot burner while cutting off the supply of fuel to said main burner and upon subsequent de-energization to set said safety control unit in condition to also supply fuel to said main burner, an electromagnet associated with said safety control unit and operative when energized to maintain said safety control valve in said last set condition, a thermocouple adapted to be heated by said pilot burner, an electric circuit between said thermocouple and said electromagnet through which said magnet is energized by said thermocouple when said thermocouple is heated, an interrupter switch interposed in said circuit and operative to open and close said circuit and thereby control the energization of said electromagnet, a normally open master switch which is operative when closed to effect the energization of said solenoid and said electric ignition element, a normally closed switch disposed in series with said master switch which is operative when opened to effect de-energization of said solenoid and said electric ignition element, a thermostatic element adapted to be heated by said pilot burner and operative when heated to maintain said normally closed switch open and when cool to maintain said normally closed switch closed, and manually actuable means by which said safety control unit is set in condition to supply fuel to said pilot burner while cutting off the supply of fuel to said main burner.

2. An automatic ignition and control apparatus as defined in claim 1 in which said master control switch and said interrupter switch are connected together to be opened and closed in unison with each other.

3. An automatic ignition and control apparatus as defined in claim 1 in which said manually actuable means comprises a depressible plunger having means to lock it in depressed position.

4. An automatic ignition and control apparatus as defined in claim 3 in which said master control switch and said interrupter switch are arranged to be opened and closed in unison with each other.

5. In an automatic ignition and control apparatus of the character described the combination of a main burner, a pilot burner operative to ignite said main burner, an electric ignition element operative when energized to ignite said pilot burner, a gaseous fuel supply manifold, a main conduit through which fuel is supplied to said main burner from said manifold, a safety control unit operative to cut oil the supply of fuel to said main burner and said pilot burner interposed in said conduit between said main burner and said manifold, a branch conduit extending between said safety control unit and "13 said pilot burner through which ,fuel'is supplied to saidv pilot burner, a solenoid operatively asso .ciated with said safety control unit, said sole noid being operative upon energization to first set said safety control unit in condition to supply fuel to said pilot burner while cutting off the supply of fuel to said main burner and upon subsequent .de-ener ;ization to set said safety control unit in condition to also supply fuel to said main burner, an electromagnet associated with said safety control unit and operative when energized to maintain said safety control *valve in said last set condition, a thermocouple adapted to be heated by said pilot burner, an electric circuit between said thermocouple and said electromagnet through which said ma znet is energized by said thermocouple when said thermocouple is heated, an interrupter switch interposed in said circuit and operative to open and close said aircult and thereby control the energization of said electromagnet, a normally open master switch which is operative when closed to effect the energization of said solenoid and said electric ignition element, a normally closed switch disposed in series with said master switch which is operative when opened to effect de-energization of said solenoid and said electric ignition element, a thermostatic element adapted to be heated by said pilot burner, and operative when heated to maintain said normally closed switch open and when cool to maintain said normally closed switch closed, a normally open supplemental interrupter switch interposed in said thermocouple circuit in parallel with said interrupter switch,

a relay operative when energized to maintain said supplemental interrupter switch closed, a

normally open supplemental master switch dis posed in series with said normally closed switch in a lay-pass circuit around said master switch and operative when closed to effect the energizertion of said solenoid said electric ignition element and said relay, and a time control mechanism operative, to close and open said supplemental master switch at predetermined set times.

6. In an automatic ignition and control apparabus of the character described the combination .of a main burner. a pilot burner operative to igni said main burner, an electric ignition element operative when energized to ignite said pilot burner, a gaseous fuel supply manifold, a main conduit through which fuel is supplied to said main burner from said manifold, a safety control unit operative to cut off the supply ,of fuel to said main burner and said pilot burner interposed in said conduit between said main burner and said manifold, a branch conduit extending between said safety control unit and said pilot burner thro gh whi h fuel is supplied to said pilot burner, a solenoid operatively associated with said safety control unit, said solenoid being operative upon energization to first set said safety control unit in condition to supply fuel to said pilot burner while cutting off the supply of fuel to said main burner and upon subsequent deenergization to set said safety control unit in con dition to also supply fuel to said main burner, an electromegnet associated with said safety control unit and operative when energized to maintainysaiol safety control valve in said last set condition, a thermocouple adapted to be heated by said pilot burner, an electric circuit between said thermocouple and said eleotromag'net through which said magnet is energized by said thermocouple when said thermocouple is heated, an interrupter switch interposed in said circuit and operative to open and close said circuit-and thereby control the ener isation of. saidxelectra magnet, .a normally open master switch which is operative when closed to effect the energizertion of said solenoid and said electric ignition-elemerit, a normally closed switch disposed in series with said master switch which is operative a normally open supplemental master switch :op-

erative when closed to effect the closing of said supplemental interrupt r switch and, the energization of said solenoid and said electric ignition element, and time control meansoperative to close and open said supplemental-master switch at predetermined set times.

"I. An automatic ignition and control apparatus as defined in claim 6 in which :said supplemental master switchis disposed in parallelwith said master switch.

8 An automatic ignition and control apparatus, as defined in claim '5, in which said relay is disposed in series with said supplemental mastei' switch in a circuit which Icy-passes said normally closed switch and said solenoid.

9. In an automatic ignition and control apparatus of the character described the -comhination of a main burner, a pilot'burner operative to ignite said main burner, an electric ignition element operative when energized to ignite said pilot burner, a gaseous fuel supply manifold, a main conduit through which fuel is supplied to said main burner from said manifold, .asafety control unit operative to cut off the supply of fuel to said main burner and said pilot burner interposed in said conduit between said main burner and said manifold, a branch conduit extending between said safety control unit and said pilot burner through which fuel is supplied to said pilot burner, a solenoid operatively associated with said safety control unit; said sole.- noid being operative upon energization to first set said safety control unit in condition to supply fuel to said pilot burner while cutting off the supply of fuel to said main burner and upon subsequent de-energization to set said safety control unit in condition to also supply fuel to said main burner, an electromagnet associated with said safety control unit and operative when energized to maintain said safety control valve in said lastset condition, thermocouple adapted to be heated by said pilot 'burnenwan electric circuit between said thermocouple and said electromagnet through which said magnet is energized by said thermocouple when said thermocouple is heatedan interrupter switch interposed in said circuit and operative to open and close said circult and thereby control the euergization of said electromasnet, a normally open master switch which is operative when closed to effect the energize-tion of said solenoid and said electric i nition element, a normally closed switch disposed in series with said master switch which is operative when opened to effect de-energization of said solenoid and said electric ignition element, means responsive to said pilot burner and operative to maintain said normally closed switch open while said pilot burner is ignited, and manually actual ble means by which said safety control unit is set in condition to supply fuel to said pilot burner while cutting off the supply of fuel to said main burner.

10. An automatic ignition and control apparatus as defined in claim 9 in which said master control switch and said interrupter switch are connected together to be opened and closed in unison with each other.

11. An automatic ignition and control apparatus as defined in claim 9 in which said manually actuable means comprises a depressible plunger having means to lock it in depressed position.

12. An automatic ignition and contro apparatus as defined in claim 11 in which said master control switch and said interrupter switch are arran ed to be opened and closed in unison with each other.

13. In an automatic ignition and control ap aratus of the character described the combination of a main burner, a pilot burner operati e to ignite said main burner, an electric i nition e ement operative when energized to ignite said pilot burner, a gaseous fuel supply manifold, a main conduit through which fuel is supplied to said main burner from said manifold, a safet control unit o erative to cut off the supply of fuel to said main burner and said pilot :burner interposed in said conduit between said main burner and said manifold, a branch conduit extending between said safety control unit and said pilot burner through which fuel is supplied to said pilot burner, a solenoid operatively associated with said safety control unit, said solenoid being operative upon energization to first set said safety cont ol unit in condition to supply fuel to said pilot burner whilecutting off the supply of fuel to said main burner and upon subsequent de-energization to set said safety control unit in condition to also, supply fuel to said main burner, an electromagnet associated with said safety control unit and operative when energized to maintain said safety control valve in said last set condition, a thermocouple adapted to be heated by said pilot burner, an electric circuit .between said thermocouple and said electromagnet through which said magnet is energized by said thermocouple when said thermocouple is heated, an interrupter switch interposed in said circuit and operative to open and close said circuit and thereby control the energization of said electromagnet, a normally open master switch which is operative when closed to effect the energization of said solenoid and said electric ignition element, a normally closed switch disposed in series with said master switch which is operative when opened to effect de-energization of said solenoid and said electric ignition element, means responsive to said pilot burner and operative to maintain said normally closed switch open while said pilot burner is ignited, a normally open supplemental interrupter switch interposed in said thermocouple circuit in parallel with said interrupter switch, a relay operative when energized to maintain said supplemental interrupter switch closed, a normally open supplemental master switch disposed in series with said normally closed switch in a by-pass circuit around said master switch and operative when closed to effect the energization of said solenoid, said electric ignition element and said relay, and a time control mechanism operative to close and open said supplemental master switch at predetermined set times.

14. In an automatic ignition and control apparatus of the character described the combination of a main burner, a pilot burner operative to ignite said main burner, an electric ignition element operative when energized to ignite said pilot burner, a gaseous fuel supply manifold, a main conduit through which fuel is supplied to said main burner from said manifold, a safety control unit operative to cut off the supply of fuel to said main burner and said pilot :burner interposed in said conduit between said main burner and said manifold, a branch conduit extending between said safety control unit and said pilot burner through which fuel is supplied to said pilot burner, a solenoid operatively associated with said safety control unit, said solenoid being operative upon energization to first set said safety control unit in condition to supply fuel to said pilot burner while cutting off the supply of fuel to said main burner and upon subsequent de-energization to set said safety control unit in condition to also supply fuel to said main burner, an electromagnet associated with said safety control unit and operative when energized to maintain said safety control valve in said last set condition, a thermocouple adapted to be heated by said pilot burner, an electric circuit between said thermocouple and said electromagnet through which said magnet is energized by said thermocouple when said thermocouple is heated, an interrupter switch interposed in said circuit and operative to open and close said circuit and thereby control the energization of said electromagnet, a normally open master switch which is operative when. closed to effect the energization of said solenoid and said electric ignition element, a normally closed switch disposed in series with said master switch which is operative when opened to effect de-energization of said solenoid and said electric ignition element, means responsive to said pilot burner and operative to maintain said normally closed switch open while said pilot burner is ignited, a normally open supplemental interrupter switch interposed in said thermocouple circuit in parallel with said interrupter switch, a normally open supplemental master switch operative when closed to effect the closing of said supplemental interrupter switch and the energization of said solenoid and said electric ignition element, and time'control means operative to close and ,open said supplemental master switch at predetermined set times.

15. An automatic ignition and control apparatus as defined in claim 14 in which said supplemental master switch is disposed in parallel with said master switch.

16. An automatic ignition and control appa ratus, as defined in claim 13, in which said relay is disposed in series with said supplemental master switch in a circuit which by-passes said normally closed switch and said solenoid.

RICHARD L. PERL. JOHN M. HOFF.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,290,048 Hildebrecht July 14, 1942 2,577,787 Mayer et a1 Dec. 11, 1951 2,578,717 Mayer et a1 Dec. 18, 1951