US2510264A - Safety control and ignition apparatus for gaseous fuel burners - Google Patents

Description

June 6, 1950 c. K. STROBEL 2.5103

smz'rv con'mor. AND IGNITION APPARATUS FOR GASEOUS FUEL BURNERS Filed Dec. 7, 1946 3 Sheets-Shem 1 Gttomcg June 6, 1950 c K STROBEL 2,510,264

SAFETY coNTRbL AND IGNITION APPARATUS FOR GASEOUS FUEL BURNERS Filed D80. 7, 1946 3 SheetsSheet 2 [/VVE/VTOR CHARLES KENNEDY STROBEL,

June 6, 1950 c. K. STROB EL 2,510,264

I SAFETY CONTROL AND IGNITION APPARATUS FOR GASEOUS FUEL BURNERS Filed Dec. 7, 1946 3 Sheets-Sheet 3 I I .T 166 172 164 7- 7" 5 Z';: II, I

"I 41/ 1M! i INVEN TOR CHARLES KENNEDY STROML,

a r TQENE r:

Patented Junefi, 1950 SAFETY CONTROL AND IGNITION APPA- RATUS FOR GASEOUS FUEL BURNERS Charles K. Strobel', Pittsburgh, Pa., assignor to Robertshaw-Fulton Controls Company, a corporation of Delaware Application December 7, 1946, Serial No. 714,788

9 Claims. 1

This invention relates to safety control and ignition apparatus for gaseous fuel burners and. more particularly, to electrically operated apparatus for oven burners independent of commercial current supply.

In copending application Serial No. 620,320 filed October 4, 1945 by Charles K. Strobel et al. and assigned to the assignee of the present application, there is disclosed a flash-tube ignition system embodying a thermoelectric safety device. The system is placed in operation by the usual manipulation of the oven gas cock which 'may include the thermostatic control for oven temperatures. An automatic thermal timing device determines the so-called starting period during which the thermoelectric device comes into operation. Upon termination of this period the fuel flow to the flash pilot burners is cutoff for theduration of the oven operation and only the thermocouple heating burner and the main burner remain in operation, the latter under control of the oven thermostat.

An object of the present invention is to render such apparatus more useful by improving the automatic nature thereof.

Another object of the invention is to utilize simple and economical timing means cooperable with the existing controls to start and stop the apparatus at desired times.

Another object of the invention is to permit the setting of dual controls at one time for automatic operation in proper sequence at a later time in the absence of the operator.

Another object of the invention is to preserve all the existing safety features intact while improving the performance of the apparatus as a unit.

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 burner embodying the invention;

Fig. 2 is a longitudinal sectional view of the having the usual oven burner l0 and top pilot burner l2 located remotely from the oven burner 10. As is customary in equipment of this nature, the various burners receive fuel from the manifold l4 connected to a source of fuel supply. In this embodiment. the top pilot burner I2 is connected by a pipe IE to the manifold 14 and is of the constant burning type.

The main oven burner I0 is supplied with fuel from the manifold 14 by a main fuel pipe 18 and the fuel supply therein is under control of means comprising a main fuel cook which may also embody the usual thermostatic control device adelectromagnetic 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 apparahis is shown in connection with a cooking range justable together with the cock by knob 2| and being responsive to temperatures in the oven where the burner I0 is located. As 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 I8 independently of the fuel cock 20 when the latter has once been opened. The flow of fuel in the pipe l8 to the main burner 10 is thus subject to the throttling action of the thermostatic device where included.

The flow of fuel in the pipe I8 to the main burner I0 is also under the control of a thermomagnetic control device designated generally by the reference numeral 22. This thermomagnetic control device 22 is interposed in the main fuel pipe 18 in proximity of the top pilot burner I2 between the main fuel cock 20 and the oven burner Ill. As shown more clearly in Fig. 2, the control device 22 comprises a casing 24 having an inlet connection 26 extending through the sidewall 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 30 having an opening 32 therethrough through which fuel may flow from the inlet 26 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 30 adjacent the inlet opening 26. The valve member 36 is secured to a valve stem 40 which extends to the opening 32 and has slidable engagement with a closure disc 42. The purpose of the closure disc is to interrupt the flow of fuel through the passage 32 when the valve member to is moved out of engagement with the seat 38 during the resetting operation to be de scribed hereinafter. To this end, a second valve seat 341 is formed on the partition til on the side opposite the valve seat and is adapted to be engaged by the closure disc 12 during the reset ting operation. A. guide portion is formed substantially concentric with the closure disc 432 for cooperation with the walls of the opening 32 and may be serrated to permit free passage of fuel thereby until the closure disc is fully en= gaged with its seat The bottom of the chamber 28 is provided with an annular projection or housing as in which a stem portion ie of the closure disc d2 is slidably mounted. A coil spring is carried by the stem 48 and is operative between the housing do and a collar 52 mounted on. the stem d8. Thus, when a force is applied to the end of the stem ill to move the closure disc 32 into engagement with its seat 44, the coil spring 553 will be compressed. When the force is removed, the bias of the spring 56 will serve to return the closure disc d2 toits open position relative to the seat it.

A yieldable connection is provided between the closure disc 42 and the valve member so 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 valve stem to which may take the form of a coil spring 5 3 housed within an axial recess in the closure disc stem to and operative between the bottom of the recess and the end of the valve stem it.

The end of the casing ZJQ adjacent the inlet 26 is provided with a closure cap 56 having a magnet housing 58 closely engaging the inner wall there of. The closure cap at its outer end supports a threaded terminal connection so. The magnet housing 58 supports a horseshoe magnet 62 which is provided with the usual winding as having one end grounded on the closure cap 58 and the op= posite end secured to the terminal connection 6b. The electromagnetic device is completed by the provision of an armature 65 which is carried by the valve stem 46 for cooperation with the pole faces of the magnet 62. It will be noted that the armature is normally spaced from the magnet a less distance than the closure disc 52 is spaced from its seat. Thus, after the armature is in attracted position the override spring 54 permits further movement of the closure disc relative to the valve stem 40. When the valve member 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 flash pilot burner I0 and an auxiliary pilot burner 12. As shown in Fig. 1, the flash pilot burner I0 is located in the oven compartment adjacent the main burner I0 while the auxiliary pilot burner 12 is located adjacent the top pilot burner I2. 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 14 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 cook 20. The fuel in the pipe 18 is preferably under control of the main fuel cock 2t but is not controlled by the thermostatic device which may be included as previously described. Thus, when the main fuel cock 2b is open the flow of fuel in the pipe is is not subject to the throttling action of the thermostatic device as is the fuel in the pipe 58.

As previously indicated, the thermomagnetic control device 22 is also adapted to control the flow of fuel to the flash pilot burner to and the auxiliary pilot burner l2. To this end, as shown more clearly in Fig. 2, the pipe N3 is connected to an inlet opening 8t extending through the wall of the casing 26 and communicating with an auxiliary fuel chamber 82 formed axially of the casing and separated from the main fuel chamber 28 by the housing at. In order to prevent leakage of fuel from one chamber to the other, the auxiliary fuel chamber 32 is provided with a diaphragm es extending thereacross adjacent the end of the closure disc stem to and maintained in position by means of a clamping ring to carried by the casing 26.

The bottom wall so oi the chamber 82 is provided with a plurality of apertures 9t providing passage for fuel from the inlet to to an outlet 92 formed in the wall of the casing 26 on the opposite side of the bottom wall so and adapted for connection to the fuel pipe M. Passage of fuel through the apertures so is controlled by an auxiliary valve member to which is movable into and out of engagement with the bottom wall 88 of the chamber 32 within which the valve member 94 is located. A valve stem 96 is secured to the valve member 9 3 and extends on either side thereof. One end of the valve stem 96 is located in chamber 82 and terminates adjacent the diaphragm 84. The auxiliary valve member at is biased into engagement with the wall 88 by a coil spring 9? 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 96. This opposite end of the valve stem 96 terminates beyond the collar 98 for operative engagement with a second diaphragm It!) which serves to prevent leakage of fuel from the casing 24 and is held in position by a second clamping ring I02 carried on the casing 2%. A reset stem tilt extends from adjacent the underside of the diaphragm we to the bottom wall of the casing 2 and is provided with 9, button H16 exterior of the casing 24 and by means of which the reset stem 104 may be reciprocated.

The electromagnet, comprising the winding 64 and horseshoe magnet 62, is adapted to be energized by current generated from a thermocouple I08 which is connected by suitable leads 0 to the terminal connection 60. The thermocouple I08 is located so that the hot junction thereof will be heated by a flame from a thermocouple heating burner H2 which receives a supply of fuel from the pipe H which also supplies fuel to the flash pilot burner I6. An ignition pilot burner H4 is provided intermediate the thermocouple heating burner H2 and the main burner [0 to receive fuel from a conduit H6 connected at a junction II! with pipe 18. As will be more apparent hereinafter, the burner H2 and the portion of the pipe 14 beyond branch pipe 16 could be dispensed with if the burner H4 is arranged to heat the thermocouple I08 and also ignite the main burner III.

A system of flash tubes is provided for igniting the various burners of the system from the constant burning top pilot burner l2. Accordingly, a short flash tube 8 is provided between the constant burning top pilot burner I2 and the auxiliary pilot burner 12, it being apparent that fuel from the pipe 16 flowing from the auxiliary pilot burner 12 will enter the flash tube H8 and be ignited from the constant burning pilot burner I2. The flame so created will then be conducted back through the flash tube H8 and will ignite 12. An elongated flash tube I20 is provided between the constant buming top pilot burner I2 and the flash pilot burner 10 which is remote therefrom. This flash tube I20 serves to cause ignition of the flash pilot burner 10 in a similar manner to that described in connection with the flash tube I18. In addition, a branch flash tube I22 extends from the flash tube I20 adjacent the flash pilot burner 10 to the thermocouple heating burner H2 and likewise serves to ignite the fuel flowing therefrom. It will be understood that if the burner II2 is dispensed with. then the flash tubes I20 and I22 would be arranged to ignite the ignition pilot burner II4 directly instead of this burner being ignited from the thermocouple heating burner I I2.

The heat of the flame from the thermocouple heater I I2 on the thermocouple I08 serves to energize the electromagnet sufllciently to hold the armature 66 against the pole faces of the magnet 62 but this thermoelectric current is incapable of moving the armature to this attracted position. Hence, resetting means is provided for placing the armature 66 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. l. g

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 12. The bracket I24 is provided with a channel-shaped portion I26 at the end opposite the control device 22 and projecting substantially midway across the bracket. The channelshap d portion I26 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, and biased apart bymeans 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 I06 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 a portion of the channel-shaped member I26 in a counter-clockwise direction and by its engagement with a set screw I40 carried by the channel-shaped portion I26 in the opposite direction.

As shown more clearly in Fig. 3, when. the re setting button I06 is unoperated, the bimetal strip I36 occupies a position at an angle to the axis of the control device 22. In this position, the bimetal strip I36 is offset from the auxiliary pilot burner '12 which projects through the bracket m substantially midway between the control device 22 and the channel-shaped portion I26. Manually operated means for moving the bimetal strip I36 and latching member I30 into substantialalignment with the axis of the conthe fuel flowing from the auxiliary pilot burner I atlases be subject to the heat of the flame from the auxiliary pilot burner 12. Moreover, in this position the reset button I06 will be forced inwardly of file control device 22 to eflect the resetting opera- The manuall 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 I30 is received. The lever I42 is pivoted on a pin I46 projecting from the bracket I24 on one side of the channel-shaped portion I28. The other arm of the lever I42 is engaged by a flexible connection in the form of a cable or pull wire I66 which is mounted on the bracket I24 and is provided with a coil spring I62 operative between the bracket I24 and the lever I42 for biasing the lever in a counter-clockwise direction. As shown in Fig. 3. when the lever 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 12. I I

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 2|. To this end, the fuel cook 20 is provided with a bracket I54 extending laterally therefrom and carrying a support I56 through which the pull wire I50 extends. The end of the wire I50 is connected to a lever I58 which is pivoted on a pin I60 carried by the bracket I54. 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 I 56. The slidable member I62 having a hooked end I64 stantially normal to the axis of the fuel cock 26 by means of a toothed portion I66 on the slidable member I62 being adapted for engagement with a lug I68 carried by the knob 2|. Theslidable 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 I66 on the slidable member I62, the latter is yieldably mounted on the bracket I54 to permit such movement. To this end. the slidable member I62 is maintained with the hooked end I64 thereo in engagement with the lever I58 by means of a spring wire I14 which ma 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 I and engages the bracket I54 to limit movement of the lever I58 as will be apparent hereinafter.

embodiment of the invention a second timing.

device I16 is included and is of differentfoi'in from the first timing device described comprising the bimetal strip I36 cooperable with the auxiliary pilot burner 12. The second timing device I16 comprises a clock timer I18 of any well known form which is manually adjustable to selected time positions for starting and stopping operation of the apparatus. To this end, the clock timer I18 includes a control valve Ill 7 carried by the fuel pipe II between the fuel cock 20 and the junction III of pipe H6. The control valve I80 is provided with a valve member I42 which is operated between open and closed positions by the clock timer "8 and will prevent flow of fuel to the auxiliary pilot burner I2, the thermocouple heating burner H2 and the ignition pilot burner I I4 when closed.

The operation of the apparatus is as follows: The clock timer 8 is first adjusted to a starting time position and stopping time position and the valve member I82 consequently will remain closed until the selected starting time is reached. The constant burning top pilot burner is assumed to be producing a flame. The fuel cock 20 is then opened by means of rotation of the knob 2| in a clockwise direction, as viewed in Fig. 4, to cause fuel to flow in the pipe I8 as far as the control device 22 and as far as the timing device I16 in pipe I8. This operation of the knob 2I will cause the lug I68 to be moved in a clockwise direction into engagement with, the toothed portion I66 on the slidable member I62 causing the pull wire I50 to be operated by means of the lever I68. The latching lever I42 will thus be moved against the bias of the spring I52 in a clockwise direction causing the latching element 530 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 from the auxiliary pilot burner I2.

The set screw I40 is now engaged by the latching element 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 is unheated, due to the clockwise torque applied at the slot I34 to the bimetal strip I36 and the counter-clockwisetorque applied at the set screw I40 to the latching element I30. The lug I60 on knob 2| has moved under and released the toothed portion I66 during the opening movementof cook 20 due to the yieldable mounting of the slidable member I62. The reset spring I52 causes the slidable member I62 to be returned to its initial position as soon as the toothed portion I66 is released from the lug I68. The unheated bimetal strip I36 remains in the latched position independent of the force applied by the pull wire I50.

The inward movement of the reset button I06 causes the reset stem I04 to move the diaphragm I and cause movement of the auxiliary valve stem 86 axially against the bias of the coil spring 91 which causes movement of the auxiliary valve member 94 from its seat. It is apparent, however, that no fuel can flow to the pilot burners I2, "2 and H4 because the clock valve member I82 is still closed.

During this resetting operation the stem 48 of the closure disc 42 is engaged by the diaphragm 84 and is moved against the bias of the spring 50 into engagement with the seat 44. The valve member 36 is simultaneously moved away from its seat 38, but fuel is prevented from flow-- ing from the passage 32 through the outlet 34 to the main burner I0 due to the immediate seating of the closure disc 42. It may be noted that immediately 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 75 of the thermostat combined with the mainfu'el- 8 such movement, due to the relative movement between the closure disc 42 and the valve stem 40.

When the clock timer "8 reaches its starting time position fuel will be admitted through pipe I8, inlet and chamber 82 through apertures 00, outlet 92 and pipe I4 to the pilot burners I0 and H2. Simultaneously, fuel flows through the branch pipe I6 to the auxiliary pilot burner I2. ignition of pilot burners I0 and H2 respectively after the auxiliary pilot burner I2 is ignited by flash tube II! from the constant burning pilot burner I2.

After a predetermined time delay, during which the bimetal strip I36 becomes sufllciently heated by the flame from the auxiliary pilot burner I2, the strip warps and trips the latching element I30. This warping of the bimetal strip I36 causes the direction of the torque at the slot I34 to be changed from clockwise to counterclockwise. Hence, the latching element I33 is rotated counter-clockwise when tripped and will move the bimetal strip I36 out of the flame of the auxiliary pilot burner I2 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 I04 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 80 through the apertures to the outlet 92 so that the flow of fuel through the pipe I4 to the flash pilot burner I0, thermocouple heating burner I I2 and auxiliary pilot burner 12 is cut off. However,

the time for heating the bimetal strip I36 sumciently to cause it to warp is made long enough so that the thermocouple I08 can become sufllciently heated by the flame from the thermocouple heating burner H2 and the ignition pilot burner H4 to generate current for energizing the electromagnet before the auxiliary valve 94 is moved to closed position. As the armature 66 is now held in attracted position against the pole faces of the magnet 62, the valve member 36 remains open while the closure disc 42 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 I0 is now permitted. This burner is ignited by the flame at the ignition pilo burner II4.

It has been mentioned that the thermocouple heating burner II 2 could be dispensed with if desired provided that the ignition pilot burner II4 be positioned to ignite the main burner I0 and also heat the thermocouple I08. Consequently, the flash pilot burner I0 would be located in the pipe H6 and. the flash tubes I20 and I22 rearranged accordingly. When the resetting operation is completed and auxiliary valve 94 closed,

then the flow of fuel to the pilot burner I2 is cutoil. The ignition pilot burner I I4 would, however, remain in operation as the pipe H6 is connected to the pipe I8 ahead of the control device 22.

If at any time during the interval between the starting and stopping time positions of the clock timer I18 the thermocouple I08 ceases to be heated by the ignition pilot burner H4, then the armature 66 will be released from the pole faces of the magnet 62 causing the safety valve member 36 to close and prevent further flow of fuel to the main burner I0. Otherwise, the apparatus will operate normally with the main burner under control The flash tubes I20 and I22 cause cock 20 until the clock timer I18 reaches its stopping time position.

At the stopping time position, the clock valve member I82 will automatically be closed to shutoff the fuel supply in the pipes I8 and H6. The ignition pilot burner I I4 will thus cease to produce a flame and the thermocouple I08 will cool and cause the safety valve 36 to close. The apparatus is thus arranged for I per cent shutoff of fuel whenever the clock timer I18 operates to close its valve member I82.

It will be observed that the first and second timing devices described are operated independently by separate manual means. This arrangement makes it possible for the latching element I30 to be set at one time and the timing device therefor, comprising bimetal strip I36, to be set to operate at any time thereafter under control of the clock timer I18. Thus, although both the latching element I30 and its timing device I36 are placed in operative condition by a single manipulation of the handle 2|, they are not actually rendered operative until the desired starting time as set by the clock timer I'I8. Moreover, the thermoelectric safety means is caused to serve two useful purposes instead of one. This occurs by reason of the use of the thermocouple I08 to determine the stopping time for the apparatus under control of the clock timer I I8, as well as its more customary use as a safety device responsive to a pilot burner flame.

It will be apparent that many changes may be made in the details of construction and arrangement and combination of parts within the scope of the appended claims without departure from the invention disclosed herein.

I claim:

1. A safety control apparatus for fuel burners having main and pilot burners and a source of fuel supply, comprising electromagnetic means having a member operable between positions for controlling the flow of fuel to the main burner and being biased to a fuel supply preventing position, means responsive to the presence of a flame at the pilot burner for causing energization of said electromagnetic means for holding said member in a fuel supplying position, resetting means operable for positioning said member in said position to supply fuel to the main burner and including a timing device adopted to be conditioned for terminating the resetting operation upon expiration of a predetermined period during which said flame responsive means has time to become responsive, conditioning means for rendering said timing device effective, and a second timing device controlling said conditioning means and being adjustable between selected time positions for initiating said period at a selected time following operation of said resetting means.

2. A safety control apparatus for fuel burners having main and pilot burners and a source of fuel supply, comprising electromagnetic means having a member operable between positions for controlling the flow of fuel to the main burner and being biased to a fuel supply preventing position, means responsive to the presence of a flame at the pilot burner for causing energization of said electromagnetic means for holding said member in a fuel supplying position, resetting means operable for positioning said member in said position to supply fuel to the main burner and including a timing device adapted to be conditioned for terminating the resetting operation upon expiration of a predetermined period during which said flame responsive means has time to become responsive,

conditioning means for rendering said timing device eflective and a second timing device controlling said conditioning means and having means for controlling the flow of fuel to the pilot burner and being adjustable between selected time positions for preventing said flow until a selected time following operation of resetting means.

8. A safety control apparatus for fuel burners I having a plurality of burners including main and pilot burners and a source of fuel supply therefor, comprising electromagnetic means having a member operable between positions for controlling the flow of fuel to at least the main burner and being biased to a fuel supply preventing position, means responsive to the presence of a flame at one of said pilot burners for causing energization of said electromagnetic means for holding said member in a fuel supplying position, resetting means operable for positioning said member in said position to supply fuel to the main burner and including a timing device operable only when the flame at another one of said pilot burners has existed for a predetermined period for terminating the resetting operation, and a second timing device having means for controlling the flow of fuel to the last said pilot burner and being adjustable between selected time positions for preventing said flow unti a selected time following operation of said resetting means.

4. A safety control apparatus for fuel burners having a main burner, a pair of pilot burners and a source of fuel supply, comprising electromagnetic means having a member operable between positions for controlling the flow of fuel to the main burner and being biased to a fuel supply preventing position, means responsive to the presence of a flame at one of the pilot burners for causing energization of said electromagnetic means for holding said member in a fuel supplying position, resetting means operable for positioning said member in said position to supply fuel to the main burner and including a device responsive to a flame at the other pilot burner for terminating the resetting operation. and a timing device having means controlling the flow of fuel to at least said other pilot burner and being adjustable between selected time positions for preventing said flow until a selected time following operation of said resetting means.

5. A safety control apparatus for fuel burners having a main burner, a pair of pilot burners and a source of fuel supply, comprising valve means operable between open and closed positions for controlling the supply of fuel to at least the main burner and being biased to said closed, position, electromagnetiemeans operatively associated with said valve means for holding the same in open position when energized, thermoelectric means responsive to the heat of a flame at one of the pilot burners and operative for energizing said electromagnetic means sufilciently to retain said valve means in said open position, resetting means operative for positioning said valve means in said open position and including a flrst timing device responsive to a flam at the other pilot burner and operativ for terminating the resetting operation. means operatively associated with said resetting means for interrupting the flow of fuel to the main burner during theresetting operation, and a second timing device adjustable to starting and stopping time positions and having means for preventing flow of fuel to said pilot burners except in the interval between said positions, said first timing device being automatically rendered operative at said starting time 11 and said thermoelectric means being rendered inoperative at said stopping time.

6. A control apparatus for fuel burners having main-and pilot burners, a main shut-off valve movable between positions for controlling the fuel supply to the burners, safet shut-off means operabl between positions for controlling the fuel supply to at least the main burner and being located remote from the main valve, means for biasing said safety means to a fuel supply preventing position, operating means for positioning said main valve, connecting means between said operating means and said safety means for positioning the latter in a fuel supply permitting po-y sition, said connecting means including a timing device adapted to be conditioned during a predetermined period for rendering said connecting means inoperative upon expiration of said period, conditioning means for rendering said timing device effective and a second timing device controlling said conditioning means and being adjustable between selected time positions for initiating said period at a selected time following operation of said operating means.

7. A control apparatus for fuel burners having main and pilot burners, a main shut-off valve movable between positions for controlling the fuel supply to the burners, safety shut-off means responsive to a flame at one of the-piot burners and operable between positions for controlling the fuel supply to at least the main burner and being located remote from the main valve, means for biasing said safety means to a fuel supply preventing position, adjustable operating means for positioning said main valve to admit fuel to the burners, connecting means between said operating means and said safety means for positioning the latter to admit fuel to the main burner,

said connecting means including a timing device,

responsive to a flame at'another of the pilot riod for rendering said connecting means inoperative, and a second timing device adjustable independently of said main valv operating means to starting and stopping time positions, said second timing device having means for preventing operative for opening said safety valve, an auxiliary burner in proximity of said constant burn ing pilot burner, a flash-tube extending between said auxiliary and constant burning pilot burners, means responsive to a flame at said auxiliary burner for rendering said valve opening means operative for a predetermined period during which said thermoelectric generator has time to become heated, and a timing device having means for preventing flow of fuel to said auxiliary and flash pilot burners except during a selected time interval following operation of said valve opening means.

9. Safety control and ignition apparatus for fuel burners comprising in combination, a main burner, a fuel supply pipe connected to the main burner, means for igniting the main burner in-- cluding a flash pilot burner in proximity of the main burner and having separate connection with valve, an auxiliary burner in proximity of said.

constant burning pilot burner, a flash-tube extending between said auxiliary and constant burning pilot burners, an auxiliary valve yieldingly urged closed, for controlling flow of fuel to said auxiliary and 'flash pilot burneramanually burners and operable after a predetermined peflow of fuel to the pilot burners except in the 8. Safety control and ignition apparatus forv fuel burners, comprising in combination, a main burner, a fuel supply pip connected to the main burner, means for igniting said main burner including a flash pilot burner in proximity of the main burner and having separate connection with said fuel supply pipe, a constant burning pilot burner positioned remote from said flash pilot burner, a flash-tube extending between said pilot burners for conducting a flame therebetween, a safety shut-off valve 'yieldingly urged closed for controlling flow of fuel to said main and flash pilot burners, electromagnetic means effective when energized for holding said safety valve open, a thermoelectric generator adapted to be heated by a flame at the flash'pilot burner for energizing said electromagnetic means but operable means for openingsaid safety and auxiliary valves, means for interrupting new of fuel to th main burner upon operation of said manually operable means, a latch loperatively associated with said manually operable means for holding said valves open, a thermal element cooperable with saidlatch and responsive to a flame at said auxiliary burner for causing said auxiliary valve to close after said thermoelectric generator has, had time to become heated, and a timing device adjustable to starting and stopping time positionsstarting time position and said thermoelectric generator being rendered inoperative atsaid stopping time position. 55

CHARLES K. S'I'ROBEL REFERENCES CITED The following references are of record in the file of this patent:

insufiiciently to open said safety valve, means Mantz June 13, 1944

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