US2883174A

US2883174A - Ignition and control system for gas burners

Info

Publication number: US2883174A
Application number: US357265A
Authority: US
Inventors: Clifton A Cobb
Original assignee: Whirlpool Corp
Current assignee: Whirlpool Corp
Priority date: 1953-05-25
Filing date: 1953-05-25
Publication date: 1959-04-21
Anticipated expiration: 1976-04-21

Description

April 21, 1959 c. A. CQBB IGNITION AND CONTROL SYSTEM FOR GAS BURNERS 272E TZZEI/ 2- Filed May 25. 1953 U te Statement IGNITION AND CONTROL SYSTEM FOR GAS BURNERS Clifton A. Cobb, St. Joseph, Mich., assignor, by mesne assignments, to Whirlpool Corporation, a corporation of Delaware Application May 25, 1953, Serial No. 357,265 6 Claims. (Cl. 263-33) This invention relates to improvements in ignition and control systems for gas burners and more particularly relates toa safety igniter circuit which has particular application to gas heated clothes driers.

A principal object of my invention is to provide a simplified and novel form of gas burner control circuit utilizing a continuous spark to ignite the gas burner.

A. further object of my invention is to provide a safety igniter circuit for gas burners wherein ignition of the gas burner is attained by a magneto.

Another object of my invention is to provide a gas burner igniter for clothes driers utilizing a magneto driven by the means for driving the drier drum, to generate a continuous spark to ignite the gas burner.

A further object of my invention is to provide a safety circuit particularly adapted for gas heated clothes driers, shutting down the gas supply on safety with less unburned gas flow than with the conventional type of units in which the gas burner is ignited by a pilot and the gas flow continues several minutes before going down.

A further object of my invention is to provide a safety igniter circuit for gas burners utilizing a continuous spark magneto to ignite the burner immediately on the turning on of the gas supply thereto, without the usual Waiting period for warm up by the pilot flame of the usual heat switch connecting the operating solenoid for the burner valve in the circuit.

A further object of my invention is to provide an igniter circuit for gas burners eliminating the usual safety pilot and the difficulties heretofore present with such pilots, caused by clogging of the pilot by the taking on of lint and the like.

Still another object of my invention is to provide a safety igniter system particularly adapted for lighting the gas burners of clothes drying machines in which a magneto is utilized to ignite the main gas burner, and the magneto is driven from the means for driving the drier drum, assuring that the circuit shut down and the gas burner will not be ignited in case the belt to the drier drum should break or run off its sheaves.

These and other objects of my invention will appear from time to time as the following specification proceeds and with reference to the accompanying drawing wherein:

Figure 1 diagrammatically shows an automatic igniter circuit and control system for gas burners constructed in accordance with my invention; and

Figure 2 is a diagrammatic view diagrammatically showing the drive connection to the drier drum and the igniter magneto.

As shown on the drawing:

In the embodiment of my invention illustrated in the drawing, the igniter and control circuit is shown as being operative to control the operation of a gas heated clothes drier and to ignite the gas burner therefor, although it need not be in such a circuit and may be utilized to ignite various types of gas burners used for other purposes. it

The gas drier may be similar to that shown and described in Patent No. 2,635,354 which issued to Peter E. Gelhof and Harold E. Morrison on April 21, 1953, and entitled Gas Heated Drier. The drier and the drive therefor need only herein be described in suflicient detail to make my present invention readily understanda'ble.

A drier drum 10 is diagrammatically shown as being driven from a motor 11 by a means of an endless belt drive means indicated generally by reference character 12. A magneto 14 which may be attached to the drier drum or an idler pulley 18 in the drive to the drier drum is shown as having spaced contacts adjacent a main gas burner 15, to provide a continuous spark there'between during operation of the drier drum 10, to ignite themain burner 15 when the supply of gas is turned on. The magneto 14 may be of any well-known form so need not herein be shown or described in detail.

Electric power to energize the motor 11 and operate: the same, to rotatably drive the drier drum 10 is pro-- vided through conductors 16 and 17, which may be connected with a suitable source of electric power, which may be the usual outlet in the home.

A door switch 19 is shown as being connected in the conductor 16 and as closing when the door is closed, to complete a circuit to the motor 11 through a contact arm 20 of a timer switch 21, operated by a timer motor 22 connected in parallel with the motor 11.

The timer switch 21 may be cam operated and the cams (not shown) operating the timer switch maybe driven through their timing cycles 'by the timer motor 22. The timer switch 21 may be of any well-known form, so need not be herein described further, except to point out that it has a second contact arm 23 electrically connected to the contact arm 20 by a conductor 24 and connecting the conductor 16 with the gas burner operating circuit, as will hereinafter be more fully described as this specification proceeds.

The conductor 24 is shown as connecting the contact arm 20 with the motor 11 to energize said motor when the contact arm 20 is in a closed position. The motor 11 is connected with the conductor 17 through a condoctor 26 and a main line switch 27 An illuminating lamp 29 and a germicidal lamp 30 are shown as being connected from a conductor 16 to the conductor 17 through the main line switch 27. The illuminating lamp 29 and germicidal lamp 30 remain lighted, regardless of whether the door is open or closed and until opening of the main line switch 2-7.

The contact arm 23 of the timer 21 is shown as connecting the conductors 16 and 24 with a limit switch 31 through a conductor 32. The limit switch 31 may be a conventional form of limit switch operable to deenergize the burner control system upon belt failure. The limit switch 31 is connected with contacts 33 of an adjustable thermostat 34. The thermostat 34 may be a. well-known form of bi-metal thermostat maintaining a circuit through a thermostatically operated combustion switch 35 to solenoid coils 36 and 37 of series connected main gas valves 39 and 40 respectively until the temperature within the drier drum exceeds the temperature for which the thermo stat is set. The solenoid coils 36 and 37 are in turn connected with the conductor 17 through a time delay relay or switch 41 and the main line switch 27. The time delay a relay 41 may have a bi-rnetal eon-tact arm 42, opening to break the circuit through a contact 43 of said switch and the solenoid coils 36 and 37, upon a predetermined timed delay interval, by the resistor heat created by the energization of a heater coil 44.

The heater coil 44 is shown as being energized through a contact 45 and contact arm 46 of the combustion switch 35 to open the time delay switch by resistor heat in a pita determined time delay interval, which may be approximately fifteen seconds;

A gas supply line 47 is shown as delivering gas to a gas cock 49 which is usually, open and which may be outside of the *drier'corrrpartment; The gas cock 49-is shown asdeliveringgas to a gas regulator 50, which also'may be outside of the drier cabinet. The gas regulator 50 mturnis connected in series with the main gas valves 39 and 40,

for-delivering gas thereto and-to the 'main burner 15'-when" said gas valves are open;

On the downstream side of the gas valve 40 is a pressure switch 51 operatinga contact arm 52, to close a circuit through a contact 53 connected with the main line conductors 16 through a conductor 54. When the contact' arm 52 is in engagement with the stationary contact 53, effected by the pressure of the gas passing through the pressure-switch 51 to the burner 15, a circuit is completed through a conductor 55 to the solenoid coils 36 and 37 for the valves 39 and 40, to maintain said valves open when In operation of the drier the switch 27 may first be closed. This will illuminate the illuminating lamp 29 and germicidal lamp 30. The drier may then be filled with clothes and the timer switch 21 set for the required time cycle. This will move'the contact arm 20 into the closed position shown in the drawing, the contact arm 23 closing upon operation of the timer motor 22 in a delayed time interval. When the door for the drier cabinet (not shown) is closed, a circuit is completed through the contact arm 20 of the timer switch 21 and the motor 11 and timer motor 22 to energize and start said motor and timer.

This effects the drive to the drier drum and the magneto 14 causing the magneto to generate a continuous spark. It will also move the'contact arm 23 to a closed position. Assuming the gas cock 49 to be open and the contact arm 23 to be in a closed position, an energizing circuit will be completed through the limit switch 31, contacts 33 of the adjustable thermostat 34, contact arm 46 of the thermostatically operated combustion switch 35 andthrough contacts 45 and 56 of said combustion switch. This will energize the solenoid coils 36 and 37 and open the main gas valves 39 and 40, the circuit being completed through the contact 43 and contact arm 42 of the time delay relay 41 and the main switch 27. The heater coil 44 will also be energized through the contact 45 of the combustion switch.

Upon opening of the gas valves 39 and 40, the pressure of gas passing through the pressure switch 51 will move the contact arm 52 of said switch into engagement with the contact 53 to complete a holding circuit around the combustionswitch 35 and to maintain the solenoid coils 36 and 37 energized.

Assuming the valves 39 and 40 are open and gas is passing through the gas burner 15, the continuous spark generated by the magneto 14 will ignite said gas burner. Upon ignition of the gas burner the heat of combustion will open the combustion switch 35. This will open the circuit to' the heater coil 14 and will also open the circuit through the contact 56 to the solenoid coils 36 and 37. The solenoid coils 36'and 37, however, will be energized through the contact arm 52 and contact 53 of the pressure switch 51; as previously mentioned' Since the contact 45 opens upon ignition of the gas burner the heater coil44 will be deenergiz'ed. This will maintain the contact arm 42 into engagement with the contact 43'and"maintain .the gas valves 39 and 40:

open.

If, however, the gas burner 15 should fail to ignite,

as by'a-failure'of'themagneto 14, or breaking thedrive' belt for the drier drum or "for any other reason, the combustion switch 35 will remain closed. The heater coil 44 will then remain energized and open the time delay relay 41, deenergizing the solenoid coils 36 and 37 and shutting off the gas supply valves 39 and 40 and the supply of gas tothe. burner 15'. The pressure-switch 51 will also open.

If at any time during operation of the drier there should be a loss of gas pressure, the pressure switch 51 willopen' Also, if for any reason the gas burner 15 shouldnot' ignite, the combustion-switch35 will remain closed and the heater coil 44 will be energized and open the time delay relay 41 and thus close the main gas valves 39 and A new cycle then' 40 for the balance of the timed cycle. cannot-be started until the time delay relay 41 has had time to cool and close its contacts, which may be a mat ter of a few minutes.

In case a belt in the drive to the drier drum 10 should break or-run off its pulleys, the magneto 14 will be inoperative to ignite the gas burner 15. When, however,

the drier'is in operation during an active drying cycle and the belt should break or runofi' 'itspulle'ys, the limit switch 31 will come into operation and open the circuit to the" solenoid coils 36 and 37 and shut down the supply of gas to the gas burner 15. The gas burner 15 then cannot be ignited until the belt is repaired and the magneto 14 is again being operated by the drive to the drier drum 10. It will be understood that various modifications and variations of the present invention may be eilected without departing from. the spirit and scope of the novel concepts thereof.

I claim'as my invention:

1. in a gas burnercontrol circuit, a gas supply line, a gas valve therein, a gas burner on the downstream side of said valve, a magneto for igniting said burner, a'solenoid coil energizable toopen said gas valve, an energizing cirwit to said solenoid including a thermally operated-combustion switch and a time delay'switch having a heater coil for opening the contacts of said time delay switch by resistor heat, said thermally operated combustion switch having one set of contacts closing the circuit to said solenoid coil and havinganother set of contacts completing an'energizing circuitto said heater coil and opening both sets of contacts by the heat of combustion generated upon the ignition of said gas burner, and a [pressure switch between said main gas valve and gas burner and having contacts closing a'circuitto said solenoid coil upon the passingof gas under pressureto said gas burner, and hc ldingsaid solenoid coil energized upon the opening of said contacts of said combustion switch.

2. In a gas burner control circuit particularly adaptable for gas heated clothes driers having a rotatable drier drum, a main gas line, a shut ofl valve in said gas line, a gas burner onthe downstream side of said shut ofi valve, a=motor, means driving said drier drum from said motor,

a continuously driven magneto driven by the means for saidmshut off valve including a time-delay switch having contacts normally closed and opening by resistonheat,

a combustion. switchuopening by the-heat of combustion upon the ignition of said gas burner, a resistor heater inwseries with said combustion switch for generating heat to open said time delay switch upon failure of said combustion switch to open, and a holding switch by-passing said combustion switch and responsive to the passage of gas to said main burner for holding said solenoid coil energized upon opening of said combustion switch upon the ignition of said burner.

3. In a gas burner control circuit particularly adapted for gas heated clothes driers having a rotatable drier drum, a gas line, a main gas valve in said gas line, a solenoid coil energizable to open said valve, a gas burner on the downstream side of said gas valve, a motor, means driven by said motor for driving said drier drum, a magneto driven by the means for driving said drier drum and generating a continuous spark to ignite said gas burner, an energizing circuit for said motor, an initial energizing circuit to said solenoid coil including a thermally operated combustion switch opening by the heat of combustion upon the ignition of said gas burner, a time delay switch, and a heater coil for said time delay switch opening said switch by resistor heat, said heater coil connected in said initial energizing circuit in series with said combustion switch, and a normal energizing circuit for said solenoid coil including a holding switch having contacts closing upon opening of said main gas valve and completing an energizing circuit to said solenoid coil by-passing said combustion switch and holding said solenoid coil energized through said time delay switch upon the opening of said combustion switch.

4. In a gas burner control circuit particularly adapted for gas heated clothes driers having a rotatably driven drier drum, a motor for driving said drum, a main gas line, a main gas valve therein, a burner on the downstream side of said valve to provide the heat for drying clothes in said drier drum, a magneto driven by said motor, an energizing circuit for said motor, a solenoid coil for opening said gas valve, an initial energizing circuit to said solenoid including a thermally operated combustion switch opening upon the heat of the combustion upon the ignition of said burner, a time delay switch having contacts completing an energizing circuit to said solenoid coil and opening by resistor [heat and having a heater coil connected in series with the contacts of said combustion switch and energized through the contacts of said combustion switch, and a holding circuit for said solenoid coil including a pressure switch completing a circuit to said solenoid coil independently of said combustion switch through the contacts of said time delay switch upon the pressure of gas passing to said burner upon opening of said main gas valve and holding said solenoid coil energized upon opening of the contacts of said combustion switch.

5. In a gas burner control circuit particularly adapted for gas heated clothes driers having a rotatable drier drum, a main gas line, a shut-01f valve in said gas line, electrically energizable means for opening said valve, a gas burner on a downstream side of said shut-off valve, a. motor, means driven by said motor for driving said drier drum, an energizing circuit to said motor including a timer having a timer switch manually closed to efiect operation of said motor to drive said drier drum, an energizing circuit for said electrically energizable means to efiect opening of said shut-0E valve to supply gas to gas burner in a predetermined time delay interval after the starting of said motor comprising a second timer switch closing after starting of said motor, and electrically energizable means energizable upon starting of said motor and prior to energization of said electrically energizable means for opening said shut-off valve, for creating a continuous spark to ignite the gas issuing from said gas burner, comprising a magneto having sparking contacts adjacent said gas burner, and a drive connection from said motor to said magneto for continuously driving said magneto as long as said motor is operating, said energizing circuit for said electrically energizable means for opening said shut-off valve including a combustion switch and a time delay switch for effecting opening of said shutoflf valve through said second timer switch, and a holding switch by-passing said combustion switch and holding said shut-off valve open through said time delay switch and said second timer switch upon opening of said combustion switch upon ignition of the burner.

6. In a gas burner control circuit particularly adapted for gas heated clothes driers having a rotatable drier drum, 'a main gas line, a shut-01f valve in said gas line, electrically energizable means energizable to open said shut-01f valve, 2. gas burner on the downstream side of said shut-01f valve, a motor, a drive connection from said motor to said drier drum, an energizing circuit to said motor including a timer and a timer operated switch manually closed to instigate operation of said motor, an energizing circuit to said electrically energizable means for opening said main gas valve to supply gas to said gas burner after the starting of said motor comprising a second timer switch closing after the starting of said motor and a time delay switch having contacts normally closed and opening upon a predetermined time interval upon failure of the burner to ignite, a combustion switch effecting opening of said time delay switch upon failure of the burner to ignite and opening by the heat of the burner flame, a pressure operated holding switch holding said electrically energizable means energized through said second timer switch and said time delay switch upon opening of said combustion switch by the heat of the burner flame, electrically energizable means energizable prior to opening of said shut-off valve for providing a continuous spark to ignite the gas issuing from said main burner comprising a magneto, a drive connection from said motor to said magneto for continuously driving said magneto during operation of said motor, and. spaced sparking contacts energized by said magneto and positioned adjacent said gas burner.

References Cited in the file of this patent UNITED STATES PATENTS 1,493,919 Cunningham May 13, 1924 2,231,420 Gille Feb. 11, 1941 2,269,157 Levine Jan. 6, 1942 2,305,544 McGrath Dec. 15, 1942 2,358,166 Isserstedt Sept. 12, 1944 2,388,969 Hess et al Nov. 13, 1945 2,456,147 Ray Dec. 14, 1948 2,484,008 Aubert Oct. 11, 1949 2,619,734 Geldhof et a1 Dec. 2, 1952 2,678,814 Geldhof et al. May 18, 1954