LATCHING SOLENOID VALVE

摘要

A pilot valve is operated by solenoid formed by a coil (52) wound around a non-magnetic spool that has a bore (56). A rare earth permanent magnet (62) is inside the bore adjacent one end and abuts a flux concentrator (58) farther inside the bore. A plunger (68) is slidably located within the bore biased away from the flux concentrator by a spring (70) and projects out another end of the bore. An enclosure of magnetic material completes a magnetic flux path around the solenoid and has an aperture through which the plunger projects. The pilot valve includes a cage (86) of rigid non-magnetic material which abuts the enclosure and has a recess which supports the plunger out of contact with the housing. The plunger selectively opens and closes a pilot tube (92) through the cage to operate a diaphragm (100) that responds by engaging a primary valve seat to control the flow of fluid through a valve body.