US Patent 9273867 Retractable ignition system

An integrated retractable burner ignition system including a burner having an outlet face and a flow passage including a front end substantially coincident with the outlet face of the burner and a gas inlet positioned rearward from the front end of the flow passage, an igniter including a high voltage electrode surrounded by an insulator and extending beyond the insulator to form a tip end of the igniter, the igniter being mounted slidably within the flow passage, an actuator connected to a rear portion of the igniter and configured to advance and retract the igniter within the flow passage, and a slidable seal between the igniter and the flow passage, the seal being positioned rearward of the gas inlet of the flow passage and frontward of the rear portion of the igniter.