Solenoid pump for heating oil - has second coil holding contacts of switch in solenoid circuit closed only after depressing spring loaded switch button

摘要

The electromagnetic pump for heating oil comprises a non-magnetisable cylinder (2) containing a magnetisable piston (1) arranged between springs (4, 5), and an exciter coil (35) with intermittent d.c. feed to reciprocate the piston. A further coil (36) is arranged co-axially relative to the coil (35) and there is an axially movable core (38) carrying the movable contacts (42, 42') of a switch (42, 42', 43, 43') in the exciter coil circuit. The core is spring loaded (39) to open the contacts, the arrangement being such that, when the contacts are closed, the coil (36) holds the core (38) against this spring action. When the contacts are open, they can only be closed by depressing a push button (37) acting on the core (38).