Latching solenoid valve

摘要

A pilot valve is operated by a solenoid formed by a coil wound around a non-magnetic spool that has a bore. A rare earth permanent magnet is inside the bore adjacent one end and abuts a flux concentrator farther inside the bore. A plunger is slidably located within the bore biased away from the flux concentrator by a spring 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 though which the plunger projects. The pilot valve includes a cage 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 through the cage to operate a diaphragm the responds by engaging a primary valve seat to control the flow of fluid through a valve body.