Spark plug for burners using fuel-air mixture - has rod-shaped centre electrode and external, annular earthing electrode separated by insulator

摘要

The spark plug is intended for burners using fuel-air mixtures, and has a rod-shaped central electrode and an external, tubular earthing electrode, between which is sandwiched an insulating body. The spak plug is provided with an outer thread for securing to the burner housing. The thread is formed on the tubular earthing electrode in a manner permitting longitudinal shifting and locking at any arbitrary position. The tubular earthing electrode may be provided with markings for location of the threaded portion, associated with different mounting depths of the spark plug. The mouting depth ensures safe igniting of the fuel-air mixture, and the desired depth is obtained by the shifting of the threaded portion.