Self-contained electric igniter with rechargeable battery

• US 4,131,413 A
• Filed: 09/09/1977
• Issued: 12/26/1978
• Est. Priority Date: 09/09/1977
• Status: Expired due to Term

• Current Assignee: AOS Holding Company (A. O. Smith Corporation)
• Original Assignee: A. O. Smith Corporation
• Inventors: Ryno, Robert W.
• Primary Examiner(s): Dority, Jr., Carroll B.
• Application Number:
  US05/831,751
• Time in Patent Office: 473 Days
• Field of Search: 431/44, 431/51, 431/52, 431/55, 431/61
• US Class Current: 431/44
• CPC Class Codes: F23N 2225/04 pressure
• CPC Class Codes: F23N 2225/12 room temperature
• CPC Class Codes: F23N 2227/22 Pilot burners
• CPC Class Codes: F23N 2227/36 Spark ignition, e.g. by means of a high voltage
• CPC Class Codes: F23N 2231/02 using electric energy accumulators
• CPC Class Codes: F23N 2235/04 in stacks
• CPC Class Codes: F23N 2235/14 electromagnetically operated
• CPC Class Codes: F23N 5/105 using electrical or electromechanical means
• CPC Class Codes: F23Q 9/12 to permit the supply to the main burner in dependence upon existence of pilot flame

Abstract

A self-contained electric igniter in which the ignition pilot is actuated by a rechargeable battery to supply energy for the spark provided by an igniter. All energy for opening the valve of the main gas valve is supplied by a millivolt thermopile generator which together with additional thermopiles charges the battery. A diode is located in the battery charging line to prevent reverse flow of current from the battery to the thermopiles. The system has a safety valve which closes off flow of gas into the system in the event the pilot burner fails to ignite and a flame switch which closes off the flow of current to the main gas valve and consequent flow of gas into the system in the event the pilot burner is extinguished. It also has a damper control system which is closed when the system is shut off to reduce stand-by losses and conserve energy.

Claims

1. A self-contained ignition system for a gas burning heating unit having a pilot burner and a main gas burner, which comprises conduit means to conduct incoming gas to the pilot burner and the main gas burner, a rechargeable battery of a predetermined capacity located in the system, an igniter electrically connected to the battery, a pilot pressure switch activated by the pressure of the gas flowing to the pilot burner to initiate current flow from the battery to the igniter and thereby provide a spark from the igniter to ignite the gas flowing from the pilot burner, a main gas valve controlling the flow of gas through the main gas burner conduit means to the main gas burner, a voltage generating means located adjacent the pilot burner and actuated by the flame of the burner to produce a voltage providing a current to electrically open the main gas valve, additional voltage generating means in series with the first generating means and located adjacent the first named generating means and heated by the main gas burner to generate a predetermined voltage, a burner pressure switch connected to the main gas burner conduit means and actuated by the pressure of the gas in the main gas burner conduit means to establish an electrical circuit between the voltage generating means and the battery to recharge the battery and means in the circuit between the battery and the voltage generating means to prevent reverse flow of current from the battery to the generating means and a safety valve disposed in the pilot burner conduit means and constructed to close within a predetermined length of time in the event the pilot burner fails to ignite the incoming gas.

2. The self-contained ignition system of claim 1 and a flame switch unit comprising a bi-metallic rod, a switch connected to the rod, a pair of lines connecting the switch across the electrical circuit from the voltage generating means to the main gas valve, and the metallic rod disposed in a position to be heated by the flame of the pilot burner so that when the flame is heating the rod the latter expands and opens the flame switch to complete the electrical circuit between the voltage generating means and the main gas valve and when the flame is extinguished the rod contracts and closes the switch to short the electrical current between the voltage generating means and the main gas valve.

3. The self-contained ignition system of claim 1, and the means to prevent reverse flow from the battery to the voltage generating means being a diode.

4. The self-contained ignition system of claim 1, and the voltage generating means comprising a first thermopile and a second and a third thermopile, and a mechanical arrangement of the respective thermopiles whereby the first thermopile is adjacent the pilot burner and the second and third thermopiles are located side by side in slightly spaced relation behind the first thermopile and spaced therefrom, and the flame of the pilot burner being provided as the split flame type to engage and encompass the first thermopile and then splitting into two tongues of flame to contact the side of the second and third thermopiles most removed from the main gas burner.

5. The self-contained ignition system of claim 4 and the thermopiles generating 750 millivolts each, and the battery having a capacity of approximately 11/2 volts.

6. The self-contained ignition system of claim 1 and the safety valve comprising an internal valve, a diaphragm connected to the valve, a spring connected to the diaphragm and valve and set to exert a predetermined pressure normally biasing the valve to an open position when the pressure on the diaphragm is equal on both sides, a bleed orifice on the one side of the diaphragm, a conduit connecting the bleed orifice to the main gas valve conduit means to supply gas and air to the safety valve through the bleed orifice to one side of the diaphragm and the gas flowing through the valve on the other side of the diaphragm to the pilot burner normally equalizing the pressure on the valve, said safety valve being closed by a build-up of pressure of incoming gas overcoming the spring and discharging gas on the one side of the diaphragm from the valve through said orifice when the pilot burner fails to light the incoming gas.

7. The self-contained ignition system of claim 1, and the pilot pressure switch having an internal switch and spaced contacts connected to the electrical circuit, and a diaphragm to actuate the switch into engagement with one or the other contacts to place the switch in a normally open or normally closed position.

8. The self-contained ignition system of claim 7, and the burner pressure switch having a construction corresponding to the construction of the pilot pressure switch.

9. The self-contained ignition system of claim 1, and a flue connected to the system to discharge combustion gases, damper means rotatably disposed in the flue, a gas operator located adjacent the lower portion of the flue and having a diaphragm disposed on the inside and dividing the gas operator into an upper and lower chamber, a conduit connected to the conduit means and to the gas operator to conduct incoming gas to the lower chamber of the gas operator, a piston extending through the upper chamber of the gas operator and connected to the diaphragm, actuator means connected to the damper means, linkage connecting the actuator means to the piston, a flue switch connected to the actuator means, and the linkage and piston rotating the actuator means to rotate the damper to an open or closed position and move the flue switch to an open or closed position when gas is discharged or removed from the chamber beneath the diaphragm to raise and lower the piston, linkage and actuator, and lines connecting the flue switch into the electrical portion of the ignition system.

10. The self-contained ignition system of claim 9, and a flame switch unit comprising a metallic rod, a switch connected to the rod, a pair of lines connecting the switch across the electrical circuit from the voltage generating means to the main gas valve, and the metallic rod disposed in a position to be heated by the flame of the pilot burner so that when the flame is heating the rod the latter expands and opens the flame switch to complete the electrical circuit between the voltage generating means and the main gas valve and when the flame is extinguished the rod contracts and closes the switch to short the electrical circuit between the voltage generating means and the main gas valve, contacts provided as a part of each switch, and the pilot pressure switch, the flue switch and the flame switch being disposed in parallel and normally closed in shunt across the main gas burner when the system is inoperative to thereby eliminate series resistance due to the contacts and permit use of low voltage in the system.