Patent attributes
A pilot-operated solenoid valve includes a pilot valve unit having a fixed core and a movable core, and a passage block formed with a valve seat which a diaphragm valve element comes into contact or separates from. The pilot valve unit includes an NO port, a common port, and an NC port. The passage block is formed with an inlet port, an outlet port, a back chamber, an NO passage, a common passage, an NC passage an external exhaust passage, and an internal exhaust passage. The solenoid valve further includes a first or second metal ball to seal the external exhaust passage or the internal exhaust passage. The passage block includes a flat cover formed with a communication passage for communicating the recess with the common port.