Burner ignition system
First Claim
1. A gas control in a gas burning system comprising a safety valve in series with a main gas valve and a pilot nozzle, the safety valve comprising a normally closed valve element for preventing gas flow to the main gas valve, a control chamber, means for increasing the pressure in the control chamber and valve control means responsive to increased pressure in the control chamber to open the valve element, the gas control further including a time delay orifice for venting the control chamber and flame responsive means for opening the main gas valve and terminating venting of the control chamber through the time delay orifice when a flame is sensed such that the safety valve closes after a predetermined delay if no flame is sensed.
7 Assignments
0 Petitions
Accused Products
Abstract
An electronic ignition system for a gas burner is battery operated. The battery voltage is applied through a DC-DC chopper to a step-up transformer to charge a capacitor which provides the ignition spark. The step-up transformer has a significant leakage reactance in order to limit current flow from the battery during initial charging of the capacitor. A tank circuit at the input of the transformer returns magnetizing current resulting from the leakage reactance to the primary in succeeding cycles. An SCR in the output circuit is gated through a voltage divider which senses current flow through a flame. Once the flame is sensed, further sparks are precluded. The same flame sensor enables a thermopile driven main valve actuating circuit. A safety valve in series with the main gas valve responds to a control pressure thermostatically applied through a diaphragm. The valve closes after a predetermined delay determined by a time delay orifice if the pilot gas is not ignited.
167 Citations
9 Claims
- 1. A gas control in a gas burning system comprising a safety valve in series with a main gas valve and a pilot nozzle, the safety valve comprising a normally closed valve element for preventing gas flow to the main gas valve, a control chamber, means for increasing the pressure in the control chamber and valve control means responsive to increased pressure in the control chamber to open the valve element, the gas control further including a time delay orifice for venting the control chamber and flame responsive means for opening the main gas valve and terminating venting of the control chamber through the time delay orifice when a flame is sensed such that the safety valve closes after a predetermined delay if no flame is sensed.
-
9. A gas control in a gas burning system comprising a safety valve in series with a main gas valve and with a pilot nozzle, the safety valve limiting the flow of gas to each of the main gas valve and the pilot nozzle and comprising:
-
an input chamber for receiving gas; a normally closed valve element for preventing gas flow from the input chamber to the main gas valve and to the pilot nozzle; a control chamber; valve control means responsive to a pressure differential between the control chamber and the input chamber to open the valve element with increased pressure in the control chamber; a thermostatically controlled valve for increasing the pressure in the control chamber; a time delay orifice for venting the control chamber; and means for venting the control chamber through the time delay orifice until a flame is sensed such that the pressure in the control chasmber is reduced and the valve element is closed after a predetermined delay if no flame is sensed.
-
Specification