Igniter for gas discharge pipe with a flame detection system

In an igniter for gas discharge pipe of the type having a tubular housing adapted to be mounted to the pipe, a fuel line extending into the housing for delivering gaseous fuel to a nozzle, the improvement comprising in combination:

• an electrode having a tip extending into the nozzle;
• an insulating sheath extending around the electrode to a point a selected distance from the tip;
• retaining means located in the housing in surrounding and sealing contact with the sheath for retaining the electrode in the housing;
• an annular passage surrounding the sheath and the electrode from the retaining means to the nozzle;
• circulating passage means connected to the annular passage near the retainer means and extending to the nozzle, for allowing hot gas in the nozzle to flow through the annular passage and circulating passage means to remove moisture from the space surrounding the electrode;
• power means for supplying a high DC voltage discharge to the electrode to create a spark to ignite the fuel, and for supplying a lower monitoring voltage to the electrode;
• and
• means for measuring current flow between the electrode tip and the housing in response to the monitoring voltage, the current flow indicating the presence of a flame.

In an igniter for a gas discharge pipe of the type having a tubular housing adapted to be mounted to the pipe, a fuel line extending into the housing for delivering gaseous fuel to a nozzle, the improvement comprising in combination:

• an electrode adapted to be connected to a source of electrical energy and having a tip extending into the nozzle for creating a spark to ignite the fuel;
• an insulating sheath extending around the electrode from its base to a point a selected distance from the tip;
• retaining means located in the housing in surrounding and sealing contact with the sheath for retaining the electrode in the housing;
• an inner tube coupled to the retaining means and extending to a point adjacent the nozzle, the inner tube surrounding the sheath and electrode and being of greater diameter than the sheath, defining an inner annular passage;
• and
• an outer tube coupled to the retaining means and extending to a point adjacent the nozzle, the outer tube surrounding the inner tube and being of a greater diameter than the inner tube, defining an outer annular passage;
• the inner tube having at least one hole located adjacent the retaining means, communicating the inner and outer passages with each other to allow hot gas in the nozzle to circulate through the inner and outer annular passages to remove moisture.