Make-and-break spark plug - has induction coil whose field rotates middle electrode about long axis to break short circuit between middle and earthing electrodes

摘要

The make-and-break spark plug finds application in burners, combustion engines, jet engines etc. for their ability to generate sufficient sparks at low voltage. It has an induction coil whose magnetic field rotates a middle electrode (14) about the longitudinal axis of the spark plug against a spring force. Thus a short circuit path between this electrode and an earthing electrode is broken and a spark is generated. The middle electrode is axially mounted. Preferably this electrode and/or a retaining armature (17) are mounted in an axial bearing (23) which may be in the form of a roller bearing. Alternately a slide bearing may be used. The middle electrode may be fitted with a labyrinth seal (16).