US2978240A - Alternating current pilot control - Google Patents

Description

April 4, 1961 J. D. EDWARDS ET AL 2,978,240

ALTERNATING CURRENT PILOT CONTROL Filed April 25, 1958 Jarnasp. Edy/ un's Gordon, ZZ/Qifffl 6469 rates 2,978,240 ALTERNATING CURRENT rnor comer.

Filed Apr. 25, 1958, Ser. No. 730,892

8 Claims. (Cl. 263- 33) The present invention relates to control arrangements for gas burners and more particularly to safety controls for gas burners of clothes dryers, stoves, hot water heaters, and the like.

An object of the invention is to provide a new and novel control arrangement for heating apparatus.

Another object of the invention is to provide a new and novel control arrangement for preventing the flow of gas to a gas burner in the event the flame of a pilot is extinguished.

Another object of the invention is to provide a control arrangement as described and including devices for controlling the flow of gas to the pilot and to the gas burner, the control device for the gas flame to the pilot being efiective to also control gas flow to the burner and to prevent the flow of gas to the pilot and burner in the event the flame of the pilot is extinguished.

Another object of the invention is to provide a control arrangement as described wherein the gas flow control device for the gas burner is connected to a timing device for controlling the duration of operation of the gas burner.

A further object of the invention is to provide a control arrangement as described for a clothes dryer and wherein the timing device is effective to cause operation of the gas flow control device for the gas burner when the clothes-receiving basket of the dryer is rotating thereby insuring the application and even distribution of heat in about and in the basket to effectively dry the clothes.

Other objects and advantages of the invention will become apparent from consideration of the following detailed description and claims and also the drawings, in which:

Fig. 1 is a perspective view of a clothes dryer with portions removed to more clearly illustrate the structure thereof;

Fig. 2 is an enlarged view partly in section and partly in elevation of the control arrangement embodying the invention.

Fig. 3 is a view illustrating a modification of the control arrangement shown in Fig. 2.

Referring to the drawing, the preferred embodiment of the invention is illustrated in its application to a clothes dryer having a cabinet 1 with a door 2 in the front thereof for loading and unloading clothes into a horizontal perforated drum or basket 3 rotatably mounted in the cabinet and driven by a motor M and pulley arrangement A, such as shown in U.S. application, Serial No. 424,431, filed April 20, 1954, now abandoned, and which motor and pulley arrangement are disposed in the rear portion of the cabinet. The cabinet 1 has fixed to the rear and side walls It: and 1b thereof a gas burner 4 of conventional form for heating the air in the casing and including a mixer or Venturi tube portion 5 having its end provided with openings for the entrance of air into the tube upon the flow of gas through the central opening 6 in the tube for mixture with the gas and issuance of the gasair mixture through the openings 8 in the side of the gas 2,978,243fi Patented Apr. 4, 1961 a valve generally indicated at 13. The valve 13 is connected to a source of gas under pressure (not shown) and flowing through a supply pipe 14 and a valve 15 to a pipe 16.

As seen in Fig. 2, the pipes 14 and 16 are connected by a pressure regulator 17 of conventional type and adapted to automatically provide a predetermined pressure of the gas from the pipe 14 to the pipe 16. Our improved control arrangement comprises the valve provided in the end wall 24 of the valve body for re ceiving one end of the pipe 16 for connecting the chamber 19 with the gas flowing from the pipe 14 through the valve 15 and the pressure regulator 1'7, The chamber 20 is defined by the partition walls 22 and 23 and communicates with the opening or port 11 in the valve body 18, the opening being threaded for receiving the coupling 10 connected to one end of the pipe 9 directing the flow of gas to the pilot burner 7.

The chamber 21, defined at one end by the partition 23, is formed in the front end of the valve body 18 which has an opening 25 receiving and in threaded engagement with the left end of .a nozzle 26, The chamber 21 thus directly communicates with the hollow internal bore of the nozzle 26 so that gas within the compartment 21 will flow through the nozzle 26 and through a metering orifice 27 in the tip 28 of the nozzle 26. The nozzle 26 extends within the central opening of the Venturi tube 5 to dispose the tip 28 within the tube.

The flow of gas from the compartment 19 to the chamber 20 is controlled by a valve member 29 in the form of a plunger having reciprocating movement in the exterior wall of the valve body 18 and having a conical valve surface St in complementary engagement with a similarly formed opening in the compartment wall 22 to control the flow of gas from the compartment 19 into the compartment 20. In the position of the plunger 29, as

7 shown, the plunger is eifective to prevent the flow of gas from the chamber 19 into the chamber 20. Upon upward movement of the plunger, it will be apparent that gas can flow from the chamber 19 into the chamber 20, through the coupling 10, the conduit 9 into the pilot burner 7.

A compression spring 31 is illustrated as being disposed between the top wall of a casing 32 and the upper end of the plunger 29 to normally urge the plunger in a downward direction to position its cone-shaped surface Si in sealing engagement with the opening in the wall 22 to prevent the flow of gas from the chamber 19 into the chamber 20. The casing 32 houses coils of an electromagnetic solenoid generally indicated at 33 which, when energized, is effective to cause the plunger or armature core 29 to be raised to move the plunger out of engagement with the wall 22 to permit the flow of gas from the chamber 19 into the chamber 29. It will be apparent that, upon deenergization of the solenoid 36, the compressed spring 31 will be effective to move the plunger 29 into sealing engagement with the wall '22 to preclude the flow of gas from the chamber'19 into the chamber 20.

When the plunger 29 is in its raised position, gas may flow from the chamber 20 into the chamber 21 by movement of a plunger 34 to a raised position to position the conical surface 35 thereof out of complementary engagement with a seat in the wall 23, the gas then flowing from the chamber 20 through the opening defined by the valve seat 35 of the wall 23 and into the chamber 21 of the valve body and the interior of the nozzle 26 and the orifice 27 thereof into the gas burner 4. The valve element, or plunger, 34 extends through and is reciprocable in the exterior wall of the valve body 18 and in an electromagnetic solenoid, generally indicated 36, and which, when the coils thereof are energized, is effective to raise the plunger 34. A compression spring 37 is disposed between the upper end of the valve element 34 and the upper wall of the casing 38 of the solenoid 36. The

spring is compressed upon energization of the solenoid and upward movement of the valve element 34, so that, when the solenoid is deenergized, the spring is effective to return the valve element to its position shown in Fig. 2 to prevent the flow of gas from the chamber 20 into the chamber 21.

In the embodiment of the invention illustrated in the drawing, a control arrangement is provided for controlling the operation of the solenoids 33 and 36 and thereby the valve 13 to permit or prevent the flow of gas to the pilot burner and to the main gas burner, including a safety control arrangement for preventing the flow of gas to the pilot and main burners in the event the flame of the pilot burner is extinguished to prevent any possibility of the accumulation of gas in the closed casing of the dryer. In addition, the control arrangement is provided with a timing device for controlling the operation of the main gas burner for a predetermined time period of the drying operation, and is also effective to control the operation of the electric motor M and thereby rotation, through the pulley arrangement A, of the basket 3 containing the clothing or fabrics to be dried. More particularly, the timing device is only effective to energize the solenoid 36 for permitting gas to flow to the gas burner when the clothes-receiving basket of the dryer is rotated, thus insuring that the main gas burner is operative for heating the air in the dryer during rotation of the basket so that the heated air will be effectively applied to dry the clothes, including the even distribution of heat about and in the rotating basket.

The safety control arrangement comprises a thermally actuated mechanism in the form of a pressure bulb 39 having a sealed pressure chamber containing a fluid capable of expanding and contracting in accordance with increases and decreases in the temperature surrounding the same. This thermally responsive element is closely positioned adjacent to the pilot burner 7 so that flames from the pilot burner impinge upon the pressure bulb 39 whereby the fluid in the pressure bulb is directly responsive to variations in temperature surrounding the pilot burner. The pressure bulb 39 is connected by a capillary tube 40 to an expandable andcontractible bellows member '41 of the type commonly known as a Sylphon bellows, the tube extending within one end of the bellows 41 and being in sealing engagement therewith to prevent the leakage of gas between the tube and bellows. The bellows 41 is connected at its other end to a rod 42 slidably supported in one end wall of a casing housing the bellows. The rod 42 is pivotally connected at its opposite end to a rotatable contact arm 43 of a switch generally indicated at 44 to position the arm 43 in engagement with a fixed contact 45. Connected to the rod 42 is a flexible member 46, which may be an overcenter spring of the leaf type having its ends fixed in a suitable manner to prevent movement thereof while permitting flexing action of the spring to one of its overcenter positions as shown, in which position the contact arm 43 is out of engagement with the fixed contact 45. When expansion of the bellows '41 and movement of the rod 42 occurs to effect engagement of the contact arm 43 with the fixed contact 45, the spring will be moved to its other overcenter position indicated by the dotted line.

During normal operation of the pilot burner, its gas flame heats the pressure bulb 39, and the increase in temperature about the surface of the bulb results in expansion of the fluid therein. The expanding fluid in the capillary tube 40 and in the bellows 41 causes the arm 42 to move and engage the fixed contact 45 to complete a circuit energizing the coils of the solenoid 33. This circuit comprises the conductor 47, connected to a suitable source of electric supply, the conductor 48, closed switch 4-4, conductor 49, coils of solenoid 33, to a conductor 54, connected to the source of electric supply. The switch 44 is in parallel with a switch indicated generally' at 50 and comprising a manually movable contact arm 51 rotatable, from the position shown, to engage a fixed contact 52 to complete a circuit including conductor 47, closed switch 50, conductor 49, coils of solenoid 33 and conductor 54. The movable contact arm 51 is provided with a tension spring 53 which is effective to hold the movable contact arm 51 in the open switch position shown and requiring movement of the arm by the operator to engage the fixed contact 52. Upon release of the contact arm 51, the tension spring 53 will be effective to move the contact arm 50 away from the fixed contact 52. In the closed position of the switch 50, the described electrical circuit causes the coils of solenoid 33 to be energized to move the armature or plunger 29 to its raised position to permit the flow of gas from pipe 16 into the chamber 19 of valve 13 and through the port in wall 22 into chamber 20 and through pipe 9 to the pilot burner 8 where the gas flowing therefrom is ignited by holding the flame of a match to the pilot burner. As the pressure bulb 39 is positioned in the flames issuing from the pilot burner 7, the fluid therein will be heated and expand to cause the bellows 41 to move the contact arm 43 to engage the fixed contact 45 thereby closing switch 44 to thereby provide a holding circuit for maintaining the solenoid 33 energized when the operator .releases the movable contact arm 51 of the switch 50 and the spring 53 moves the contact arm away from the contact 52. It will be apparent that, in the event the gas flame issuing from the pilot burner is extinguished, resultant cooling of the fluid in the pressure bulb 39 will rapidly occur and the bellows 41 will contract to move the rod 42 and disengage the movable contact arm 43 from the fixed contact 45. Opening of the switch 44 causes de-energization of the solenoid 33 with the consequence that the compressed spring 31 will immediately cause the plunger 29 to he moved in the position shown to prevent any flow of gas from the pipe 16 to the pilot burner. As the solenoid 33 also controls the flow of the gas to the pilot burner, as well as to the chamber 21 of the valve and nozzle 26 directing the flow of gas into the main burner, de-energization of the solenoid 33 and closing of the opening in the wall 22 by the plunger 30 will prevent gas being supplied to the main burner 4.

An electrical circuit is provided for energizing the solenoid 36 to permit gas to flow from the chamber 20 of the valve into the chamber 21. and thence through the nozzle 26 into the main burner. This circuit comprises a switch 55 connected by a conductor 56 to the coils of the solenoid 36, the switch 55 having a rotatable contact arm 57 manually movable from the position shown, to engage a fixed contact 58. A time-controlled switch, generally indicated at T, is disposed in series relation to the switch 55 and may be powered by' any conventional type mechanism adapted to close the contacts of a switch for a predetermined timer period. More particularly, the switch T comprises a rotatable contact arm 59 connected to a conductor 60 terminating at the fixed contact 58 of the switch 55, the contact arm 59 being operated by suitable timing mechanism for moving the arm 59 from its left dotted line open switch position to engage and move across a semi-circular contact 61 for a predetermined period of time to position the conductor 60 in current-transmitting relationship with the conductor 47.

The movable contact arm 59 rotates in a clockwise direction until it disengages the strip and is disposed in the right dotted line open switch position shown.

Assuming that the solenoid 33 is energized, manually operated switch 55 is closed and the time-controlled switch is functioning, a circuit Will be established to energize the solenoid 36 and motor M, the circuit for energizing the solenoid. 36 including conductor 47, contact 61 and the movable contact arm 59 of switch T, conductor 60, contact 58 and contact arm 57 of switch 55, conductor es, the coils of the solenoid 36, and conductor 62' connected to conductor 54. Upon. energization of the solenoid 36, the armature or plunger 34 will be moved to its raised position to permit gas to flow from the chamber 29 to the chamber 21 of the valve and through the nozzle as into the main gas burner for igni tion by the pilot burner. Upon termination of the predetermined time period for the drying operation, the contact arm 59 will disengage the contact 61 to break this circuit to de-energize the solenoid 36 and the compressed spring 37 will move the armature or plunger 34 to the position shown in Fig. 2 to prevent the flow of gas into the gas burner 4.

During operation of the switch T, the motor M and solenoid 36 are simultaneously energized, as the switch T also completes a circuit for the motor M, this circuit including conductor 47, closed contacts 61 and 59 of switch T, a conductor 63 connected to contact arm 59, and the motor M, a conductor 64 connected to the motor M, and conductor 54.

In the operation of the dryer, the switch 53 must be closed and held in its closed position to establish a circuit energizing the solenoid 33 to permit gas to flow through the valve chambers 19 and 2% to the pilot burner 7, the gas then being ignited by a match flame. Upon the flames from the burner heating the fluid in the temperature-responsive member 39, the expansion of fluid in the member 3? is transmitted through the capillary tube 40 to the bellows 41 to close the switch 44 to establish a holding circuit maintaining the solenoid 33 energized so that the manually-operated contact arm 51 may be released to open the switch 50 by the spring 53. It will be apparent that, should the pilot flame be extinguished by drafts, the fluid in the temperature-responsive member will cool and contract to cause the bellows 41 to operate to open the switch 44 to de-energize the solenoid 33 and thereby cause the plunger 29 thereof to close the opening between the chambers 19 and 20 to prevent the flow of gas to the pilot burner.

Upon closing of the switch 44 to maintain ignition of the pilot burner flame, the manually operated switch 55 is closed and the time-controlled switch T is activated to close the contacts 59 and 61 for a predetermined period of time. Closing of the switches will establish circuits energizing the solenoid 36 to raise the plunger 34 of the valve to permit gas to flow from the chamber 20 to the chamber 21 of the valve and through the nozzle to the main burner 41 for ignition by the pilot burner flame, and simultaneously the motor M will be energized to operate the pulley arrangement A to rotate the clothesreceiving basket of the dryer. When the timing mechanism of the switch T has operated for a predetermined time period, the switch T is opened to concurrently cause de-energization of motor M and also solenoid 36, thereby effecting operation of the plunger 34 to prevent a the flow of gas to the main burner and also to stop rotation of the basket or drum 3 of the dryer. During dryer basket rotation and main gas burner operation, the heated air is applied and evenly distributed about and in the basket to effectively dry the clothes.

In the event the flame of the pilot burner is extinguished during the drying operation, the temperatureresponsive switching arrangement wili be immediately 7 and to the main gas burner 4, the basket continuing rotation until lapse of the predetermined time period of the switch T when opening of the contacts 59 and 61 of the switch break the circuit for the motor M.

In the event it is desired to air dry theclothes in the basket 3 and without the application of heated air, the switch 55 can remain in its open position, as shown, and the time-controlled switch T may be operated to complete a circuit for energizing the motor M, this circuit, including conductor 47, closed contacts 59 and 651 of switch T, conductor 63, motor M, conductor 64 to conductor 54.

Fig. 3 illustrates another embodiment of the invention and wherein the control arrangement is eflective to prevent operation of the dryer, including the motor M, in the event the pilot flame is extinguished during operation of the dryer. For this purpose, the control arrangernent of Fig. 3 illustrates electric circuitry differing from that'shown in Fig. 2 and, more particularly, it comprises a conductor 65 connected ,to the upper terminal of the winding of the solenoid 32 and to the contact 61 of the timer T, the conductor 4? also being connected to the conductor 65 to establish a circuit including the conductor 47 through either the set of contacts 51 and 52 or the set of contacts 45, 43, when one or the other of these sets of contacts are closed, to the conductor 65, contacts 61 and 59, winding of motor M, and conductor 54 to establish a circuit energizing the motor M.

It will be apparent that, should the pilot light be extinguished, the subsequent cooling and contraction of the fluid in the pressure bulb 39 will cause the bellows member to contract, as previously described, and the rod 42 will move to disengage the contacts 43 and 45 of the switch 44 to break the circuit to the electric motor M, as well as to Winding of the solenoid 33 to close the valve associated therewith to cut off the supply of gas to the pilot and main burners.

.Although specific embodiments of the invention have been described, it is apparent that modifications may be made by those skilled in the art and without departing from the spirit and scope of the invention as set forth in the appended claims.

What is claimed is:

1. In a gas heated clothes dryer, a rotatable clothesreceiving container; a motor for rotating said container; a main gas burner; a pilot burner; a first normallyclosed valve controlling the supply of gas to said main burner; a second normally-closed valve controlling the supply of gas to said first valve and to said pilot burner; a second solenoid for opening said second valve for supplying gas to said first valve and to said pilot burner; a timer having a switch closing upon the setting of the timer to initiate the drying operation and which opens after the lapse of a predetermined time period to termiopen during the absence of flame in said pilot burner and closed during the presence of flame in said pilot burner; a first manually-operable switch; a second switch manually movable to closed position and spring actuatable to normally open position, said first solenoid being electrically connected to said circuit through said timer switch and said first manually-operable switch, said second solenoid being electrically connected to said circuit through said second switch in the closed position thereof to permit ignition of the gas in the pilot burner and actuation of the flame-controlled switch to maintain said second solenoid energized upon movement of the second switch to open position, said motor being electrically connected to said circuit through said timer switch, said flame-controlled switch being opened by the heat-responsive means during'theabsence of flame in said pilot burner to deenergize the second solenoid to prevent gas supply to said pilot and main burners.

2 In a gas heated clothes dryer, a rotatable clothesreceiving container; a motor for rotating said container; a main gas burner; a pilot burner; a first normally-closed solenoid-operated valve controlling the supply of gas to said main burner; a second normally-closed solenoidoperated valve controlling the supply of gas to said first valve and to said pilot burner; an electric encrgization circuit; a timer having a switch closing upon the setting of the timer to initiate the drying operation and which opens after the lapse of a predetermined time period to terminate the drying operation; a first manually-operable normally open switch; heat-responsive means actuatable by the presence of a flame in said pilot burner and including a switch open during the absence of flame in said pilot burner and being arranged in parallel with said manually-operable switch, the winding of the solenoid of the second valve being electrically connected to said circuit by closing of either said flame-controlled switch or said manually-operable switch, said manually-operable switch being initially closed to energize said second valve solenoid winding to open the second valve to permit ignition of the gas flowing to the pilot burner and thereafter being maintained energized upon closing of the flame-controlled switch in response to the presence of the flame in the pilot burner; and a second switch manually operable to closed and open positions and arranged in series with the timer switch, the winding of the solenoid of the first valve being electrically connected to said circuit by closing of the second manuallyoperable and timer switche to permit gas to flow to the main burner, said motor being electrically connected to said circuit by said timer switch in the closed position thereof to energize said motor, said flame-controlled switch being opened by the heat-responsive means during the absence of flame in said pilot burner to deenergize the second solenoid to prevent gas supply to said pilot and main burners.

3. In a gas heated clothes dryer, a rotatable clothesreceiving container; a main gas burner; a pilot burner; 21 first normally-closed solenoid-operated valve controlling the supply of gas to said main burner; a second normally-closed solenoid-operated valve controlling the supply of gas to said first valve and to said pilot burner; an electric encrgization circuit; a timer having a switch closing upon the setting of the timer to initiate the drying operation and which opens after the lapse of a predetermined, time period to terminate the drying operation; a first manually-operable normally-open switch; heat-responsive means actuatable by the presence of a flame in said pilot burner and including a switch open during the absence of flame in said pilot burner and closed during the presence of flame in said pilot burner and being arranged in parallel with said manually-operable switch, the winding of the solenoid of the second valve being electrically connected to said circuit by closing of either said flame-controlled switch or said manuallyoperable switch, said manually-operable switch being initially closed to open the second valve to permit ignition of the gas flowing to the pilot burner and thereafter being maintained energized upon closing of the flamecontrolled switch in response to the presence of the flame in the pilot burner; and a second switch manually operable to closed and open positions and arranged in series with the timer switch, the winding of the solenoid of the first valve being electrically connected to said circuit by closing of the second manually-operable and timer switches to permit gas to flow to the main burner, said flame-controlled switch being opened by the heat-responsive means during the absence of flame in said pilot burner to deenergize the second solenoid to prevent gas supply to said pilot and main burners.

4-. In a gas heated clothes dryer, a rotatable clothesreceiving container; a main gas burner; a pilot burner; a first normally-closed solenoid-operated valve controlling the supply of gas to said main burner; a second normally-closed solenoid-operated valve controlling the supply of gas to said first valve and to said pilot burner; an electric encrgization circuit; a first manually-operable normally-open switch; heat-responsive means actuatable by the presence of a flame. in said pilot burner and including a switch open during the absence of flame in said pilot burner and being arranged in parallel with the first switch, the winding of the solenoid of the second valve being electrically connected to said circuit by closing of either said flame-controlled switch or said manually-operable switch, said manually-operable switch being initially closed to open the second valve to permit ignition of the gas flowing to the pilot burner and thereafter being opened upon closing of the flame-controlled switch in response to the presence of the flame in the pilot burner; a second switch manually operable to closed and open positions, the winding of the solenoid of the first valve being electrically connected to said circuit by closing of said second manually-operable switch to permit gas to flow to the main burner, said flame-controlled switch being opened by the heat-responsive means during the absence of flame in said pilot burner to deenergize the second solenoid to prevent gas supply to said pilot and main burners.

5. In a gas heated clothes dryer, a rotatable clothesreceiving container; a motor for rotating said container; a main gas burner; a pilot burner; a first normally-open solenoid-operated valve controlling the supply of gas to said main burner; a second normally-open solenoid-operated valve controlling the supply of gas to said first valve and to said pilot burner; an electric encrgization circuit; a timer having a switch closing upon the setting of the timer to initiate the drying operation and which opens after the lapse of a predetermined timer period to terminate the drying operation; a first manually-operable normally-open switch; heat-responsive means actuatable by the presence of a flame in said pilot burner; a switch connected to said heat-responsive means and having contacts movable to an open position during the absence of flame in said pilot burner and movable to a closed position during the presence of flame in said pilot burner and being arranged in parallel with said manually operable switch, and an over-center spring connected to and operative on said switch contacts to releasably hold the contacts in one or the other position to which the contacts are moved by the heat-responsive means, the winding of the solenoid of the second valve being electrically connected to said circuit by closing of either said flame-controlled switch or said manually-operable switch, said manuallyoperable switch being initially closed to energize said second valve solenoid winding to open the second valve to permit ignition of the gas flowing to the pilot burner and thereafter being maintained energized upon closing or" the flame-controlled switch in response to the presence of the flame in the pilot burner; and a second manuallyoperable switch having closed and open positions and arranged in series with the timer switch, the winding of the solenoid of the first valve being electrically connected to said circuit by closing of the second manually-operable and timer switches to permit gas to flow to the main burner. said motor being electrically connected to said circuit by said timer switch in the closed position thereof to energize said motor, said flame-controlled switch being opened by said heat responsive means during the absence of flame in said pilot burner to deenergize said second solenoid to prevent gas supply to said pilot and main burners.

6. In a gas heated clothes dryer, a rotatable clothesreceiving container; a main gas burner; a pilot burner; a first solenoid-operated valve controlling the supply of gas to said main burner; a second solenoid-operated valve controlling the supply of gas to said first valve and to a 9 said pilot burner; an electric energization circuit; a first manually-operable normally-open switch; heat-responsive means actuatable by the presence of a flame in said pilot burner; a switch connected to said heat-responsive means and having contacts relativelymovable to an open position during the absence of flame in said pilot burner and movable to a closedposition during the presence of flame in said pilot burner and being arranged in parallel with the first switch in saidcircuit, and an over-center spring connected to and operative on said switch contacts to releasably hold the contacts in one or the other of said positions to which the contacts are relatively moved by the heat-responsive means; the winding of the solenoid of the second valve being electrically connected to said circuit by closing of either said flame-controlled switch or said manually operable switch, said manually operable switch being initially closed to open the second valve to permit ignition of the gas flowing to the pilot burner and thereafter being opened upon closing of the flame-controlled switch in response to the presence of the flame in the pilot burner; and a second switch manually operable to closed and open positions, the winding of the solenoid ofthe first valve being electrically connected to said circuit by closing of said second switch to permit gas to flow to the main burner, the contacts of said flame: controlled switch being opened by said heat-responsive means during the absence of flame in said pilot burnerto deenergize said second solenoid to prevent gas supply 7. In a gas heated clothes dryer, a rotatable clothes- 10 l burner, said motor being electrically connected to said circuit by closing of said timer switch and closing of either said first switch or said flame-controlled switch to energize said motor, said flame-controlled switch being opened by the heat-responsive means during the absence of flame in said pilot burner to simultaneously deenergize the second solenoid to prevent gas-supply to said pilot and main burners and to deenergize said motor.

8. In a gas heated clothes dryer, a rotatable clothesreceiving container; a motor for rotating said container; a main gas burner; a pilot burner; a first normally-open solenoid-operated valve controlling the supply of gas to said main burner; a second normally-open solenoidoperated valve controlling the supply of gas to said first valve and to said pilot burner; an electric energization circuit; a first manually-operable normally open switch; heat-responsive means actuatable by the presence of a flame in said pilot burner; a switch connected to said heat-responsive means and having contacts movable to an open position during the absence of flame in said pilot burner and movable to a closed position during the presence of flame in said pilot burner and being arranged in parallel with said manually operable switch in said circuit, and an over-center spring connected to and operative on said switch contacts to releasably hold the contacts in one or the other positions to which the contacts are moved by the heat-responsive means, thewinding of the solenoid of the second .valve being electrically connected to said circuit'by closing of either receiving container; a motor for rotating said container;

a main gas burner; a pilot burner; a first normally-closed solenoid-operated valve controlling thesupply of gas to said main burner; a second normally-closed solenoidoperated valve controlling the supply of gas to said first valve and to said'pilot burner; an electric energization circuit; a timer having a switch closing upon the setting,

of the timer to initiate the drying operation and which opens after the lapse of a predetermined time period to terminate the drying operation; a first manually-operable normally open switch; heat-responsive means actuatable by the presence of a flame in said pilot burner and including a switch open during the absence of flame in said pilot burner and being arranged in parallel'withr said manually-operable, switch in said circuit, the windingofl v the solenoid of the second valve being electrically con nected to said circuit by closing of either said flame-controlled switch or said manually-operable .switch, said manually-operableswitch being initially closed to energize said second valve solenoid winding to open'the second valve'to permit ignition of the gas flowing to the pilot burner and thereafter said second valve solenoid being maintained energized upon closing of the flamecontrolled switch in response to the presence of the flame .ing of the timer switch to permit gas to flow to the main said flame-controlled switch or said manually-operable switch, said manually-operable switch being initially closed to energize said second valve solenoid winding to open the second valve to permit ignition of the gas. flowing to the pilot burner and thereafter being maintained energized upon closing of the flame-controlled switch in} response to the presence of the flame in the pilot burner; a timer having a switch closing upon the setting of the timer to initiate the drying operation and which opens after the lapse of a predetermined timer period to terminate the drying operation, said timer switch being arranged in series relation to said manually operable switch and said flame-controlled switch, and with said motor and the Winding of the solenoid of the first valve in said circuit to energize the first valve solenoid to permit gas toflow' to themain burner and to energize said motor upon closing of said timer switch, said flame-comt'rolledswitch being opened by said heat responsive means said pilot and-main burners and to deenergize said motor.

References Cited in the file of this patent UNITED STATES PATENTS Nagel Apr; 22, 1952 Sotfer Jan. 21, 1958

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