US2515476A - Safety control and ignition apparatus for gaseous fuel burners - Google Patents

Description

July 18, 1950 c. K. STROBEL 2,515,476

SAFETY CONTROL AND IGNITION APPARATUS FOR GASEOUS FUEL BURNERS Filed Aug. 26, 1946 3 She,ets$heet 1 INVENTOR. CHflRLE-S K.JTROBEL.

H T TORNE Y.

y 8, 1950 c. K. STROBEL 2,515,476

' SAFETY CONTROL AND IGNITION APPARATUS FOR GASEOUS FUEL BURNERS Filed Aug. 26, 1946 3 Sheets-Sheet 2 IN VEN TOR.

CHAR/.55 A. .STROBEL.

has

HTTORNE X July 18, 1950 c. K. STROBEL 2,515,476

SAFETY CONTROL AND IGNITION APPARATUS FOR GASEOUS FUEL BURNERS Filed Aug. 26, 1946 3 Sheets-Sheet 3 INVENTOR. CHARLES K. \STROBEL.

ms HTT'ORNEK Patented July 18, 1950 SAFETY CONTROL AND IGNITION APPARA- TU S FOR GASEOUS FUEL BURNERS Charles K. Strobe], Pittsburgh, Pa., assignor to Robertshaw-Fulton Controls Company, a corporation of Delaware Application August 26, 1946, Serial No. 693,063

Claims. 1

This invention relates to safety control and ignition apparatus for gaseous fuel burners and, more particularly, to an electrical ignition system for use with electrically operated safety controls or oven burners.

In the copending application of Strobel and Lakota, Serial No. 620,320, filed October 4, 1945, owned by the applicants assignee, there is disclosed a flash-tube ignition system in which a thermoelectric safety device is operated by manipulation of the oven thermostat knob and by a thermal timing device during the so-called resetting operation. Thus, when the thermostat knob is turned to On" position, gaseous fuel is supplied directly to a heater for the thermocouple of the thermoelectric safety device. Simultaneously, the thermoelectric safety valve is latched in a starting position where the flow of fuel to the main burner is prevented but flow of fuel to an auxiliary pilot and to the oven flash-tube ports is permitted. After a predetermined time, the auxiliary pilot flame causes the thermal timer to operate and automatically release the latch. This causes the fuel supply to the auxiliary pilot and oven flash-tube ports to be shut-01f. If, at the expiration of this predetermined period, the thermocouple has been sufficiently heated by the flame at the thermocouple heater, then the flow of fuel to the main burner will be permitted. The safety feature of preventing the flow of main burner fuel during resetting and whenever the flame is extinguished during normal operation are thus present.

There exists a demand for a safety control and ignition system of the foregoing described type but, at the same time, there is also a demand for a system embodying electrical ignition instead of the flash-tube ignition described. An object of this invention, therefore, is to electrically ignite gaseous fuel burners having the safety control features described.

Another object of the invention is to utilize the principal features of the flash-tube system in the electrical ignition 'system so that conversion from one to the other is facilitated.

Another object of the invention is to utilize power from an outside source for starting purposes only and thereafter to place the safety control system under sole influence of the thermoelectric moans.

Another object of the invention is to utilize the electrical ignition means during the starting period only and thereafter discontinue exposure thereof to the heat of any flame.

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

Fig. 1 is a perspective view of a safety control and ignition apparatus for an oven fuel burner embodying the invention;

Fig. 1a is a perspective view of a portion of the apparatus shown in Fig. 1 but in modified form;

Fig. 1b is a perspective view of a portion of the apparatus shown in Fig. 1, but further modified;

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 apparatus is shown in connection with a cooking range having the usual oven burner la! and top pilot burner l2 located remotely from the oven burner l0. As is customary in equipment of this nature, the various burners receive fuel from the manifold M connected to a source of fuel supply. In this embodiment the top pilot burner I2 is connected by a pipe It to the manifold M and is of the constant burning type.

The main oven burner I0 is supplied with fuel from the manifold M by a main fuel pipe l8 and the fuel supply therein is under control of means comprising a main fuel cook 20 which may also embody the usual thermostatic control device (not shown) adjustable together with the cock 20 by knob 2| and being responsive to tem perature in the oven where the burner Ill is located. As such combined fuel cocks and thermostatic devices are well known further description is deemed unnecessary, it being understood that the thermostatic device is capable of controlling the flow of fuel in the pipe l8 independently of the fuel cook 20 when the latter has once been opened. The flow of fuel in the pipe l8 to the main burner I0 is thus subject to the throttling action of the thermostatic device where included.

The flow of fuel in the pipe Hi to the main burner I0 is also under the control of a thermoma-gnetic control device designated generally by the, reference numeral 22. This thermomagnetic control device 22 is interposed in the main fuel pipe IS in proximity of the top pilot burner l2 between the main fuel cook 20 and the oven burner it. 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 casing 24 adjacent one end and communicating with a main fuel chamber 28 extending axially of the casing 24. The main fuel chamber 28 is provided with a partition 38 having an opening 32 therethrough through which the fuel may flow from the inlet 28 to an outlet 34 formed in the wall of the casing 24 at the opposite end of the chamber 28. The inlet 26 and outlet 34 serve as connections for opposite ends of the fuel pipe l8 as will be apparent from Fig. 1 of the drawings.

The passage 32 is controlled by a safety valve 36 which is movable into and out of engagement with a valve seat 38 formed on the side of the partition 88 adiacent the inlet opening 26. The valve member 36 is secured to a valve stem 48 which extends to the opening 32 and has slidable engagement with the closure disc 42. The purpose of the closure disc 42 is to interrupt the flow of fuel to the passage 32 when the valve member 36 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 38 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 82 and may be serrated to permit free passage of fuel thereby until the closure disc 42 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 42 is slidably mounted. A coil spring 58 is carried by the stem 48 and is operative between the housing 46 and a collar 52 formed 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 58 will be compressed. When the force is removed, the bias of the spring 58 will serve to return the closure disc 42 to its open position relative to the seat 44.

A yieldable connection is provided between the closure disc 42 and the valve member 36 to permit relative movement therebetween as will be more apparent hereinafter. To this end, there is provided an override mechanism in association with the closure disc 42 and the valve stem 48 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 this recess and the end of the valve stem 48.

The end of the casing 24 adjacent the inlet 26 is provided with a closure cap 56 having a magnet housing 58 closely engaging the inner wall thereof. The closure cap 56 at its outer end supports a threaded terminal connection 68. 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 68. The electro-magnetic device is completed by the provision of an armature 68 carried by the valve stem 48 for cooperation with the pole faces of the magnet 62. It will be noted that the armature 66 is normally spaced from the magnet 62 a less distance than the closure disc 42 is spaced from its seat. Thus, after the armature 66 is in attracted position, the override spring 64 will permit further movement of closure disc 42 relative to the valve stem 48. when the valve memher 36 is fully disengaged from its seat 38, 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 thermocouple heating burner 18 and an auxiliary pilot burner 12. As shown in Fig. 1, the thermocouple heating burner 18 is located in the oven compartment adjacent the main burner I8 while the auxiliary pilot burner I2 is located adjacent the top pilot burner l2. Both burners are supplied with fuel by a pipe 14 extending from the control device 22, the auxiliary pilot burner 12 being conveniently connected to pipe 14 by a branch pipe 16. The inlet for fuel to the pipe I4 is connected to the control device '22 and may take the form of a pipe 18 connected at the opposite end to the main fuel cock 28. The fuel in the pipe 18 is preferably under control of the main fuel cock 28 but is not controlled by the thermostatic device which may be included as previously described. Thus, when the main fuel cock 28 is open, the flow of fuel in the pipe 18 is not subject to the throttling action of the thermostatic device as is the fuel in the pipe l8.

As previously indicated, the thermomagnetic control device 22 is also adapted to control the flow of fuel to the thermocouple heating burner 18 and the auxiliary pilot burner 12. To this end, as shown more clearly in Fig. 2, the pipe 18 is connected to an inlet opening 88 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 98 providing passage for fuel from the inlet 88 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 88 is controlled by an auxiliary valve member 84 which is movable into and out of engagement with the bottom wall 88 of the chamber 82 within which the valve member 94 is located. A valve stem 96 is secured to the valve member 94 and extends on either side thereof. One end of the valve stem 96 is located in the 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 98 carried on the valve stem 86. This opposite end of the valve stem 96 terminates beyond the collar 98 for operative engagement with a second diaphragm I88 which serves to prevent leakage of fuel from the casing 24 and is held in position by a second clamping ring I82 carried on the casing 24. A reset stem I84 extends adjacent the underside of the diaphragm I88 through the bottom wall of the casing 24 and is provided with a button I86 exterior of the casing 24 and by means of which the reset stem I04 may be reciprocated.

The electromagnet comprising the winding 84 and horseshoe magnet 82 is adapted to be energized by current generated from the thermocouple I08 which is connected by suitable leads IIO to the terminal connection 60. The thermo couple I08 is located so that the hot junction thereof will be heated by the flame from the thermocouple heating burner I0. If desired, an ignition pilot burner II4 may be provided intermediate the thermocouple heating burner I and the main burner I0 and may receive fuel from a conduit II8 connected to the pipe I8. However, as shown in Fig. 1a the ignition pilot burne I may be dispensed with and the thermocouple I08 located to be heated by a flame from the thermocouple heating burner I0 and from the main burner I0. A further variation would be to dispense with the thermocouple heating burner I0 and locate the thermocouple I08 to be heated by the ignition pilot burner II4 only. as shown in Fig. 112.

A flash-tube H8 is provided between the con stant burning top pilot burner I2 and the auxiliary pilot burner I2. The arrangement is such that fuel from the pipe 16 flowing from the auxiliary pilot burner i2 will enter the flash-tube II8 and be ignited from the constant pilot burner I2. The flame so created will then be conducted back through the flash-tube i i8 and will ignite the fuel flowing from the auxiliary pilot burner I2.

In this embodiment of the invention, the thermocouple heating burner I0 or, alternatively, the ignition pilot burner N4 of Fig. 1b is provided with electrical igniting means. This means takes the form of an ignition coil II5 which, as shown in Fig. l, is located adjacent an igniter port ill on the thermocouple heating burner H0. The opposite ends of the igniter H5 are connected by wires H9 and I 2| respectively to the opposite terminals of the secondary of a transformer I123. The primary of the transformer H23 has its opposite terminals connected b wires H2 and I25 to the opposite poles of a double-break switch I21 having one end of a pivoted operating element I29 associated therewith. The opposite end of the operating element I29 is secured to the button 008 as shown more clearly in Fig. 2. The switch M1 is thus adapted to be opened and closed by operation of element I29 as will be apparent hereinafter and when closed will connect wires H2 and I25 to line wires I3I and I33 respectively. The line wires I3I and I33 are connected to a suitable source of electrical energy, such as 115 volts house current, and the transformer I23 will serve to step down this current to approximately 6 volts for consumption at the igniter II5.

' It is apparent that energization of the igniter II 5 when the switch I2] is closed will serve to ignite fuel flowing from the port I I1 of the thermocouple heating burner I0. The flame so produced at the port I I1 will serve to ignite fuel flowing from an adjacent port I3I also formed in the thermocouple heating burner I0. The flame from the adjacent port I31 serves to heat the thermocouple I08 which will energize the magnet 62 sufiiciently to hold the armature 86 against the pole faces thereof. This thermoelectric current. however, is incapable of moving the armature 86 to this attracted position. Hence, resetting means are provided for placing the armature $8 in attracted position and will now be described in connection with the detailed views in Figs. 3, 4 and 5, together with the more general showing of Fig. lot the drawings.

The control device 22 is provided with a bracket I24 extending toward the top pilot burner I2 and forming a support for the auxiliary pilot burner I2. The bracket I24 is provided with a channelshaped portion I28 at the end opposite the control device 22 and projecting substantially midway across the bracket. The channel-shaped portion I28 provides spaced bearings for a pivot I28 upon which a latching member I30 is mounted. The latching member I30 is preferably made in two parts, one slidable on the other which carries the pivot I28, and biased apart by means of a coil spring I32 interposed therebetween. The slidable portion of the latching member I30 is provided with a slot I34 extending across one end thereof and offset from the center. Extending between the slot I34 and the reset button I08 is a timing device comprising a bimetal strip I36 which is retained in position on the reset button I06 by the provision of a transverse slot I38 disposed centrally thereof. Pivotal movement of the latching member I30 is restricted by its engagement with the channel-shaped portion I 28 in a counter-clockwise direction and by its engagement with a set-screw I40 carried by the channel-shaped portion I26 in the opposite direc tion.

As shown more clearly in Fig. 3, although the resetting button I08 is unoperated, the bimetal strip I38 occupies a position at an angle to the axis of the control device 22. In this position the bimetal strip I36 is ofiset from the auxiliary pilot burner I2 which projects through the bracket I24 substantially midway between the control device 22 and the channel-shaped portion I28. Manually operable means for moving the bimetal strip I36 and latching member I30 into substantial alignment with the axis of the control device 22 are provided and it will be apparent that in such position the bimetal strip i38 will be subject to the heat of the flame from the auxiliary pilot burner I2. Moreover, in this position, the reset button I08 will be forced inwardly of the control device 22 to effect the resetting operation.

The manually operable means includes a lever I42 provided with an angular portion I44 on one arm thereof having an aperture I46 therethrough in which the slidable portion of the latching member I 30 is received. The lever I42 is pivoted on a pin I48 projecting from the bracket I24 on one side of the channel-shaped portion I26. The other arm of the lever I42 is engaged by a flexible connection in the form of a cable or pull wire I50 which is mounted on the bracket I24 and is provided with a coil spring I52 operative between the bracket I24 and the lever I42 for biasing the latter in a counter-clockwise direction. As shown in Fig. 3, when the lever I42 is thus biased the bimetal strip I36 is held in its angular position out of the path of the flame from'the auxiliary pilot burner I2.

The pull wire I50 extends toward the manifold I4 of the range and is connected by means now to be described with the main fuel cock 20 for operation by the knob 2I. To this end, the

fuel cock 28 is provided with a bracket I54 (Figs.

4 and 5) extending laterally therefrom and carrying a support I56 through which the pull wire I50 extends. The end of the wire I50 i connected to a lever I58 which is pivoted on a pin I carried by the bracket I64. Movement of the lever I58 in one direction serves to exert a pull on the wire I50 against the bias of the spring I52 and thus permits operation of the latching element I30. Such movement of the lever I58 is effected by a slidable member I62 having a hooked end I64 adapted to operatively engage the lever I56. The slldable member I 62 is movable in a path substantially normal to the axis of the fuel cook 20 by means of a toothed portion I66 on the siidable member I62 being adapted for engagement with a lug I68 carried by the knob 2I. The siidable member I62 is supported on the bracket I54 and its movement relative thereto is limited by the provision of a slot I10 formed in the slidable member I62 for cooperation with a pin I12 carried by the bracket I54.

In order that the lug I66 on the knob 2I may pass beyond the toothed portion I 66 on the slidable member I62, the latter is yieldably mounted on the bracket I 54 to permit such movement. To this end, the siidable member I62 is maintained with the hooked end I64 thereon in engagement with the lever I58 by means of a spring wire I14 which may be mounted at one end on the pin I12 and having its opposite end hooked in a perforation I13 in slidable member I62. A stop in the form of an arm I15 is secured to the pin I60 and engages the bracket I54 to limit movement of the lever I58, as will be apparent hereinafter.

The pivoted operating element I29 for the switch I21 is secured to the button I06 so that reciprocation of the latter will cause the pivotal movement of the operating element I29. Thus, when the parts are in the position shown in Fig. 2 of the drawings, the switch I21 is in open posi-- tion. However, when the button I06 is moved toward the control body 24 during the resetting operation, then the switch I21 will be closed due to pivotal movement of the operating element I29.

The operation of the safety control and ignition apparatus is as follows: It may be assumed that the constant burning pilot burner I2 is producing a flame and that the fuel cock has been opened by means of rotation of the knob 2I in a clockwise direction as viewed in Fig. 4 to cause fuel to flow in the pipes I8 and 16 as far as the control device 22. Where an ignition pilot burner, such as the burner H4, is provided, this burner will receive fuel from pipes 18 and H6 at this time. This rotary operation of the knob 2| will cause the lug I 68 to be moved in a clockwise direction into engagement with the toothed portion I66 on the siidable member I62 causing the pull wire I50 to be operated by means of the lever I58. The latching lever I42 will thus be moved against the bias of the spring I52 in a clockwise direction causing the latching element I to move the adjacent end of the bimetal strip I36 also in a clockwise direction until it is aligned with the axis of the control device 22 and in the path of the flame of the auxiliary pilot burner 12.

The set screw I is now engaged by the latching member I30 and it will be apparent that the reset button I06 is thus forced inwardly and is maintained in such position while the bimetal strip I36 is unheated due to the clockwise torque applied at the slot I 34 to the bimetal strip I36 and the counter-clockwise torque applied at the set-screw I40 to the latching element I30. The lug I68 on knob 2I has moved under and released the toothed portion I66 during the opening movement of cock 20 due to the yieldable mounting of the siidable member I62. The reset spring I52 causes the siidable member I62 to be returned to its initial position as soon as the toothed portion 8 I 66 is released from the lug I66. The unheated bimetal strip I36 remains in the latched position ilrggependent of the force applied by the pull wire The inward movement of the reset button I" causes the reset stem I04 to move the diaphragm I00 and cause movement of the auxiliary valve stem 96 axially against the bias of the coil spring 91 which causes movement of the auxiliary valve member 94 from its seat. Fuel is thus permitted to flow from the pipe 16, inlet 60 and chamber 62 through the apertures 90, outlet 92 and pipe 14 for supplying the thermocouple heating burner 10. Simultaneously, fuel flows through the branch pipe 16 to the auxiliary pilot burner 12.

During this resetting operation, the stem 46 of the closure disc 42 is engaged by the diaphragm 64 and is moved against the bias of the spring II into engagement with the seat 44. The valve member 36 is simultaneously moved away from its seat 36, but fuel is prevented from flowing from the passage 32 to the outlet 34 to the main burner I0 due to the immediate seating of the closure disc 42. -It may be noted that immedi-- ately prior to engagement of the closure disc 42 with its seat 44 that the armature 66 has been placed in contact with the pole faces of the horseshoe magnet 62. However, the closure disc 42 can thereafter be moved into engagement with the seat 44 due to the provision of the override spring 54 which is compressed during such movement due to the relative movement between the closure disc 42 and the valve stem 40.

The longitudinal movement of the reset button I06 causes the operating element I29 for the switch I21 to rotate on its pivot and to close the switch I 21. The circuit of the transformer I22 is thus completed and the ignition coil III becomes energized. The thermocouple heating burner 10 is receiving fuel at this time as described and a flame is produced at the ports H1 and I31 due to operation of the igniter III. Moreover, as the auxiliary burner 12 is receiving a supply of fuel, the flash-tube] I8 causes ignition of this burner from the constant burning pilot burner I2.

After a predetermined time delay during which the bimetal strip I36 becomes sufliciently heated by the flame from the auxiliary pilot burner 12. the strip warps and trips the latching element III. This warping of the bimetal strip I 36 causes the direction of the torque at the slot I34 to be changed from clockwise to counter-clockwise. Hence, the latching element I30 is rotated counter-clockwise and will move the bimetal strip I36 out of the flame of the auxiliary pilot burner 12 to its initial cold position and simultaneously relieve the force upon the reset button I06.

The system is now in its steady state operating condition. The retraction of the reset stem I64 has caused the auxiliary valve 94 to be moved under the bias of the spring 91 into engagement with its seat to prevent flow of fuel from the inlet through the apertures to the outlet 92 so that the flow of fuel through the pipe 14 to the thermocouple heating burner 10 and auxiliary pilot burner 12 is cut-off. However, the time for heating the bimetal strip I36 sufliciently to cause it to warp is made long enough so that the thermocouple I06 can become sufficiently heated by the flame from the thermocouple heating burner 10 (and the ignition pilot burner I I4 where used) to generate current for energizing the winding 64 of magnet 62 before the auxiliary valve 64 is moved to closed position.

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Such energization of the magnet 02 causes the armature 56 to be held in attracted position against the pole faces of the magnet 62 and the valve member 36 remains open. The closure disc 42 now becomes disengaged from the seat 44 under the bias of the coil spring 50. Flow of fuel from the inlet 26, passage 32 and outlet 34 to the main burner I is now permitted. This burner is ignited by the flame at the ignition pilot burner I I4 or, in the embodiment disclosed in Fig. 1*, by the flame at the thermocouple heating burner 10. The ignition coil II becomes deenergized upon retraction of the reset stem I04 due to the operating element I29 being rotated on its pivot by movement of the reset button I06 to open the switch I21.

It may be noted that in the embodiment of Fig. 1 where the ignition pilot burner H4 is dispensed with, it becomes necessary for the thermocouple heating burner I0 to be positioned to ignite the main burner I0. As the flow of fuel to this burner I0 is cut-off by closure of the auxiliary valve 94 when the resetting operation is completed and the closure disc 42 has only at that time left its seat 44, it is also necessary that the unconsumed fuel remaining in pipe I4 after the auxiliary valve 94 closes be relied upon to continue the flame at this burner I0 until the main burner I0 is ignited thereby. Moreover, after the thermocouple heating burner I0 ceases it will be necessary for the thermocouple I08 to be heated by the flame from the main burner I0. An advantage of the arrangement is that a IOO-per-cent shut-off of fuel is obtained upon operation of the safety control.-

Where, as in the embodiment of Figs. 1 and 1 the ignition pilot burner H4 is employed, it is unnecessary to locate the thermocouple I08 to be heated by the flame of the main burner I0 or to rely upon residual fuel in pipe 14 to ignite the main burner I0. In this arrangement, however, a 100-per-cent shut-off is not possible due to the pipe i it being connected to pipe I8 ahead of the control device 22.

It will be observed, moreover, that in the embodiments of Figs. 1 and 1 the ignition coil H5 is exposed to a flame only during the starting period. Thereafter, the fuel supply through the igniter port II! is cut-off. This feature should prolong the life of the ignition coil I I5 as will be apparent. However, the system can be arranged as disclosed in Fig. 1 by dispensing with the thermocouple heating burner I0 and locating the igniter I I5 near the ignition pilot burner II4. Thus, the flame from this ignition pilot burner lit could be relied upon to heat the thermocouple lllB and also to ignite the fuel flowing from the main burner I0. In this embodiment, the pipe I4 would be plugged at its junction with the pipe "I6 so that fuel would flow from the outlet $2 to the auxiliary pilot burner I2 only. The igniter in the arrangement of Fig. 1 would, of course, be exposed continuously to the flame from the ignition pilot burner II4 during the starting and running periods.

If at any time during the operation of the apparatus the thermocouple I08 ceases to be heated by the flame from the ignition pilot burner H4, or the main burner I0 where the ignition pilot burner l I4 is dispensed with, then the armature 66 will be released from the pole faces of the magnet 62 causing the valve member 36 to become engaged with its seat 38 and prevent flow of fuel to the main burner I0. The knob 2| may be operated in a counter-clockwise direction to its original Off position upon termination of operation of the oven burner I0. During this return movement' of the knob 2|, the lug I60 will again pass under the toothed portion I66 but in reverse direction due to the yieldable mounting of the slidable member I62 on the bracket I54.

Electric ignition systems have in the past been objectionable Where a thermal timer has been manually set. This is due to the fact that such devices will not recycle in case of power failure. In this invention it is not necessary for the system to recycle in such a case since it is controlled by the power generated by a thermocouple. The external power supply failure will thus not affeet the steady state operation. It is apparent, moreover, that the same basic equipment may be used for either a flash-tube ignition system as disclosed in the aforesaid copending application or for the electric ignition system disclosed herein. In both cases an automatic means of resetting the thermoelectric safety device has been provided and is operable by merely manipulating the usual knob of a main fuel cock from Off to On position or to a desired temperature setting where a combined thermostat and main fuel cock is provided. It will be apparent that many changes can be made in the arrangement and combination of parts and in the details of construction shown and described within the scope of the appended claims.

I claim:

1. A safety control and ignition apparatus for fuel burners having main and auxiliary burners, comprising control means operable between positions and biased to one of said positions for controlling the flow of fuel to the main burner, electromagnetic means operatively associated with said control means and adapted when energized for holding the same in another said position; an electric igniter located in lighting proximity to the main burner, thermoelectric means responsive to a flame at the main burner for energizing said electromagnetic means sufficiently to hold the same in said other position but being incapable of actuating the same to said other position, reset means operable for resetting said electromagnetic means for holding said control means in said other position and energizing said igniter, said reset means including a device responsive to a flame at the auxiliary burner for rendering said reset means inoperative after a predetermined period of resetting operation during which said thermoelectric means has time to become heated.

2. A safety control and ignition apparatus for fuel burners having main, auxiliary and pilot burners and a source of electric energy, comprising control means operable between positions and being biased to one of said positions for controlling the flow of fuel to at least the main burner, electromagnetic means operatively associated with said control means and adapted when energized for holding the same in another said position, an electric igniter located in proximity of the pilot burner and connected tobe energized from the source for lighting the pilot burner to produce a flame at the main burner, thermoelectric means responsive to the heat of a flame" at the pilot burner for energizing said electromagnetic means sufliciently to hold the same in said other position but being incapable of actuating the same to said other position, and reset means operable for resetting said electromagnetic means for holding said control means in said other position and energizing said igniter, said reset means including means eflective upon operation of said reset means for maintaining the same in operative position and a device responsive to a flame at the auxiliary burner for rendering said maintaining means inoperative after a predetermined period of resetting operation during which said thermoelectric means has time to become heated.

3. A safety control and ignition apparatus for fuel burners having main, auxiliary and pilot burners, comprising a valve member movable between open and closed positions for controlling the flow of fuel to the main burner and being biased to a closed position, electromagnetic means effective when deenergized for causing said valve member to close, a thermoelectric generator adapted to be heated by a flame at the main burner for energizing said electromagnetic means, an auxiliary valve member movable between open and closed positions for controlling the flow of fuel to the auxiliary and pilot burners, manually operable reset means for opening both said valve members, means operatively associated with said reset means for interrupting the flow of fuel to the main burner, an electric igniter located in proximity of the pilot burner for igniting the same to produce a flame at the main burner, and means operable for closing a circuit to said igniter upon operation of said manually operable means, said reset means including means effective upon operation of said reset means for maintaining the same in operative position and a device responsive to a flame at the auxiliary burner for rendering said reset means inoperative after a predetermined period of resetting operation during which said thermoelectric generator has time to become heated and causing said auxiliary valve member to close and said igniter circuit closing means to be opened.

4. A safety control and ignition apparatus for fuel burners having main, auxiliary and pilot burners, comprising a first valve member movable between open and closed positions for controlling the flow of fuel to the main burner and being biased to a closed position, electromagnetic means effective when deenergized for causing said first valve member to close, a thermoelectric generator adapted to be heated by a flame at the main burner for energizing said electromagnetic means, an auxiliary valve member movable between open and closed positions for controlling the flow of fuel to the auxiliary and pilot burners,

means operable to an open position independently I of said first valve member for interrupting the flow of fuel to the main burner, an electric igniter located in proximity of the pilot burner for igniting the same to produce a flame at the main burner, switching means operable for closing a circuit to said igniter, and manually operable reset means for opening said first and auxiliary valve members and causing operation of said flow interrupting means, said manually operable means including a connection to said switching means for operating the same for closing said circuit, a latching device effective upon operation of said reset means for maintaining the same in operative position and a thermal element movable into the path of a flame at the auxiliary burner, said element being responsive to said flame for moving out of the path thereof after said generator has had time to become-heated and causing said auxiliary valve member to close and said switching means to open said circuit.

5. In a control and ignition system for fuel burning apparatus having a source of electric energy, the combination of an electric igniter for the fuel adapted to be connected to be'energized from the source, manually operable shut-oi! means for the fuel supply, control means biased to a position to prevent said fuel supply at least when said shut-off means is moved to an inoperative position, electromagnetic means operatively associated with said control means and adapted when energized for holding the same in another position to permit said fuel supply, thermoelectric means adapted to be responsive to the heat of the burning fuel at the apparatus for energizing said electromagnetic means but insufflciently to overcome said bias, reset means operatively associated with said shut-off means and being movable therewith to a position for overcoming said bias and resetting said electromagnetic means for holding said control means in said other position, and a normally open switch controlling energization of said igniter and being operatively associated with said reset means for operation to closed position during the resetting operation.

6. A system as set forth in claim 5 wherein said reset means includes a latching device effective upon operation of said shut-off means to said inoperative position for maintaining said reset means in said position thereof and said switch in said closed position, and timing means operatively associated with said latching device for tripping the same after a predetermined period of resetting operation and being rendered effective by movement of said reset means to said position.

7. In a control and ignition system for fuel burners having main and pilot burners and a source of electric energy, the combination of an electric igniter for the pilot burner connected to be energized from the source, manually operable shut-off means for the fuel supply to the main and pilot burners, control means biased to a position to prevent said fuel supply to at least the main burner when said shut-off means is moved to an inoperative position, electromagnetic means operatively associated with said control means and adapted when energized for holding the same in another position to permit said fuel supply. thermoelectric means responsive to the heat of a flame at the pilot burner for energizing said electromagnetic means but insufllciently to overcome said bias, reset means operatively associated with said shut-off means and being movable therewith to a position for overcoming said bias and resetting said electromagnetic means for holding said control means in said other position, and a normally open switch controlling energization of said igniter and being operatively associated with said reset means for operation to closed position during the resetting operation.

8. A system as set forth in claim 7 wherein said reset means includes a latching device effective upon operation of said shut-off means to said inoperative position for maintaining said reset means in said position thereof and said switch in said closed position, thermally responsive timing means operatively associated with said latch ing device for tripping the same after a predetermined period of resetting operation, and heating means for said timing means effective upon movement of said reset means to said position.

9. In a control and ignition system for fuel burners having main and pilot burners and a source of electric energy, the combination of an electric igniter for the pilot burner connected i to be energized from the source, manually rotatabie shut-off means for the fuel supply to the main and pilot burners, control means biased to a position to prevent said fuel supply to at least the main burner when said shut-off means is moved to an inoperative position, electromagnetic means operatively associated with said control means and adapted when energized for holding the same in another position to permit said fuel supply, thermoelelectric means responsive to the heat of a flame at the pilot burner for energizing said electromagnetic means but insuliciently to overcome said bias, reset means including a reset stem movable axially into operative engagement with said control means for overcoming said bias and resetting said electromagnetic means for holding said control means in said other position, a normally open switch for controlling energization of said igniter, switch operating means carried by said reset stem for closing said switch upon said axial movement of said stem, and connecting means extending between said shut-oil means and said stem for causing said axial movement upon manual rotation of said shut-off means to said inoperative position.

10. In a control and ignition system for apparatus having a constant burning pilot burner, a main'burner and an ignition pilot burner and a source of electric energy, the combination of an electric igniter for the ignition pilot burner and connected to be energized from the source,

manually rotatable shut-off means for the fuel supply to the main and ignition pilot burners, a control body located adjacent the constant burning pilot burner, a valve member reciprocable in holding said valve member open, thermoelectric means responsive to the heat of a flame at the ignition pilot burner for energizing said electromagnetic means, a reset stem projecting exteriorly of said body and operatively engageable with said valve member for opening the same in a resetting operation when moved inwardly of said body, a normally open switch controlling energization of said igniter, switch operating means carried by the projecting portion of said stem for closing said switch during said resetting operation, means carried by said stem for interrupting flow between said fuel inlet and outlet connections during the resetting operation, a latching device, connecting means between said shut off means and said latching device for operating the latter to latching position, an auxiliary pilot burner adjacent said latching device, means for igniting said auxiliary pilot burner from said constant burning pilot burner, and a bimetalelement operable between said reset stem and said latching device for movement into the path of a flame at said auxiliary pilot burner, said element being responsive to said flame for releasing said latching device after a predetermined period during which said thermoelectric means becomes heated.

CHARLES K. STROBEL.

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 al Oct. 7, 1941 2,261,092 Peterson Oct. 28, 1941 2,290,048 Hildebrecht July '14, 1942 2,391,753 Strobei Dec. 25, 1945 2,406,925 Strobel Sept. 3, 1946 2,446,718 Ray Aug. 10, 1948

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