US3144898A

US3144898A - Direct ignition system

Info

Publication number: US3144898A
Application number: US134497A
Authority: US
Inventors: Queever Lawrence
Original assignee: Controls Company of America
Current assignee: Controls Company of America
Priority date: 1961-08-28
Filing date: 1961-08-28
Publication date: 1964-08-18
Anticipated expiration: 1981-08-18

Description

Aug. 18, 1964 QUEEVER 3,144,898

DIRECT IGNITION SYSTEM 7 Filed Aug. 28, 1961 u m a m IO n 4 A MW 4 4 MM M. N m w .w. O c. v V 5 m O 2 2 4 4 5 |l||| 4| J 3 8 f S 8 M II! T .m 00 MM 2 3 RH M T 3 9 L FIIL nvwszvron. LAWRENCE QUEEVER MAW An'oauev United States Patent of Delaware Filed Aug. 28, 1961, Ser. No. 134,497 4 Claims. c1. 15s-125 This invention relates to an improved ignition system for gas burners and particularly to an improved automatic direct spark ignition system.

The object of the present invention is to provide a simple spark ignition system which is safe under all normal and abnormal operating conditions.

This object is accomplished by connecting a power type ignition transformer, a flame sensor, and a thermally responsive timer with a valve that is operated by controlling the magnetic flux density of a solenoid arranged to operate the valve. After the valve is opened, the magnetic flux density is reduced to a value sufficient to hold the valve open but insuflicient to reopen the valve. If the system should be de-energized for any reason and then re-energized the valve cannot reopen until the magnetic flux density is raised to a value suflicient to open the valve. The solenoid operated valve is connected in circuit with the ignition transformer so that the solenoid valve will be energized when the transformer is energized so that a spark will normally be present across the electrodes when the valve opens. The timer is connected in circuit with the valve operator to open the circuit after a predetermined period of time in the absence of a flame in the burner. The flame sensor is connected in the circuit to de-energize the timer and the ignition transformer and to reduce the magnetic flux density to a value sufficient to hold the valve open if ignition does occur in the burner.

Other objects and advantages will be pointed out in or be apparent from the specification and claims, as will obvious modifications of the single embodiment shown in the drawing.

Referring to the drawing, an electromagnetically operated valve is shown having a valve head 12 that cooperates with valve seat 14 to control the flow of fuel from the inlet 16 to outlet 18. The valve is opened by energizing coils 2i and 22 wound around valve stem 24 providing a solenoid action on the valve stem. Spring 26 is provided to bias the valve in a closing direction.

The coils are connected across lines L L and on a cold start are energized if line switch 23 is closed and thermostat 24 closes calling for heat. Coil 20 is connected across the line L L through line 28, bimetal transfer switch blade 30, line 32 and line 34. Coil 22 is connected across the line through

lines

36, 38, and 40, bimetal heater 42, resistance 44 and line 46. With this circuit arrangement, both coils will be simultaneously energized when the room thermostat closes.

A power type ignition transformer 48 has primary winding 50 connected by

lines

52 and 54 in parallel with coil 20 through the bimetal transfer switch blade 20 for simultaneous energization of the transformer and coil upon closure of room thermostat 24. Energization of the primary winding causes a spark across electrodes 56 which are connected to secondary winding 58 of the transformer. If ignition occurs in the burner, flame sensor 60 will open normally closed switch 62 opening line 46. The ignition transformer and coil 22 will thus be deenergized. Coil 20 will still be energized and will hold the valve open until de-energized by the room thermostat. When the thermostat opens, coil 20 is de-energized allowing valve 12 to close. The flame sensor will normally cool off sufliciently to close switch 62 before the 3,144,898 Patented Aug. 18, 1964 thermostat again closes. If the room thermostat should reclose immediately after opening or a momentary power failure should occur, the valve would not open since coil 20 would be de-energized and the valve would remain closed even though the thermostat" 24 recloses or power is restored to the line and coil 20 is re-energized. The valve will not reopen until the flame sensor cools off sufliciently to close switch 62 re-energizing coil 22 and the ignition transformer. This prevents the possibility of an explosive quantity of gas accumulating in the burner before a spark appears across the electrodes.

If ignition does not occur (by reason of a burned out transformer or failure of the spark) after a predetermined period of time, bimetal blade 30 will warp due to the heat produced by heater 42, disengaging from contact 64 and engaging contact 66. This opens circuit 32 deenergizing coil 20 and the spark ignition transformer 50. Closing of the switch blade 30 with contact 66 energizes the bimetal heater 42 and resistance element 44 through

lines

28, 68, 4t and 46. This shunts coil 22. The valve will close and will remain closed until either the thermostat or the line switch is opened to dc-energize the heater and the delay switch returns to contact 64. The resistance element 44 will limit the current through the bimetal heater to prevent the possibility of the heater burning out if the room thermostat should remain closed for any length of time. Since heater 42 and element 44 are in series with coil 22 and both coils must be energized to open the valve, a burn-out in either 42 or 44 will prevent opening the valve.

Although but one embodiment of the present invention has been illustrated and described, it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit of the invention or from the scope of the appended claims.

I claim:

1. A fuel burning system comprising, an electromagnetic fuel valve having two coils which jointly produce suflicient force to open the valve while one of said coils only produces enough force to hold the valve open, an electric ignitor for igniting the fuel, a time delay switch, electric circuit means for energizing said coils and said ignitor with the ignitor and one of said coils connected in parallel through said time delay switch, said time delay switch including an electric heater for actuating the switch, said heater being connected in series with the other of said coils, a thermostat for controlling energization of said circuit means, said delay switch being operative when actuated by its heater to de-energize said one coil, said circuit means including a normal open branch circuit closed by said time delay switch when actuated by said heater to continue the energization of the heater to thereby keep the delay switch actuated.

2. A system according to claim 1 in which the switch is a SPDT switch having a normal position in which one coil is across the line under control of the thermostat and an actuated position in which the circuit through said one coil is broken and a circuit shunting the other coil is made.

3. A system according to claim 2 including a normally closed flame switch responsive to the heat of ignited fuel and connected between said circuit means and one side of a power line to open the circuit through said other coil and said heater and said ignitor.

4. A fuel burning system comprising, an electromagnetic fuel valve having two coils, only one of which is necessary to hold the valve open but which requires energization of both coils to open the valve, a thermostat, an electric circuit controlled by the thermostat and having two parallel branches, an ignitor for igniting fuel passed by the valve, a normally closed flame switch opening in response to the heat of burning fuel, a normally closed time delay switch movable from a normal position to an actuated position, an electrically energized motor for actuating the delay switch, one branch including one valve coil and the delay switch when in normally closed position whereby said one coil is energized only while the delay switch is in its normal position, the other branch including the other coil and said motor and said flame switch all in series whereby opening the flame switch will de-energize the motor and said other coil, said ignitor being connected between the branches in series with the flame switch and with said time delay switch so as to be de-energized by actuation of the delay switch or opening 4 the flame switch, said electric circuit including a normally open shunt circuit around said other coil, said delay switch in its actuated position closing said shunt circuit whereby to shunt said other coil while continuing energization of said motor.

References Cited in the file of this patent UNITED STATES PATENTS 1,689,803 Schroeder Oct. 30, 1928 1,835,028 Eiseman Dec. 8, 1931 1,908,493 Bogle May 9, 1933 2,380,640 Eskin July 31, 1945 3,026,932 Algino Mar. 27, 1962

Claims

1. A FUEL BURNING SYSTEM COMPRISING, AN ELECTROMAGNETIC FUEL VALVE HAVING TWO COILS WHICH JOINTLY PRODUCE SUFFICIENT FORCE TO OPEN THE VALVE WHILE ONE OF SAID COILS ONLY PRODUCES ENOUGH FORCE TO HOLD THE VALVE OPEN, AN ELECTRIC IGNITOR FOR IGNITING THE FUEL, A TIME DELAY SWITCH, ELECTRIC CIRCUIT MEANS FOR ENERGIZING SAID COILS AND SAID IGNITOR WITH THE IGNITOR AND ONE OF SAID COILS CONNECTED IN PARALLEL THROUGH SAID TIME DELAY SWITCH, SAID TIME DELAY SWITCH INCLUDING AN ELECTRIC HEATER FOR ACTUATING THE SWITCH, SAID HEATER BEING CONNECTED IN SERIES WITH THE OTHER OF SAID COILS, A THERMOSTAT FOR CONTROLLING ENERGIZATION OF SAID CIRCUIT MEANS, SAID DELAY SWITCH BEING OPERATIVE WHEN ACTUATED BY ITS HEATER TO DE-ENERGIZE SAID ONE COIL, SAID CIRCUIT MEANS INCLUDING A NORMAL OPEN BRANCH CIRCUIT CLOSED BY SAID TIME DELAY SWITCH WHEN ACTUATED BY SAID HEATER TO CONTINUE THE ENERGIZATION OF THE HEATER TO THEREBY KEEP THE DELAY SWITCH ACTUATED.