Example: 3/2 way normally closed solenoid valve
A 2/2 way solenoid valve is equipped with a diaphragm (3) in which there is one bleed orifice (4), and one pilot orifice (1). When the solenoid is energized, it opens the pilot orifice and releases pressure from the pilot chamber (2). This results in overpressure in the bottom of the diaphragm which is lifted by the line pressure opening the main orifice.
When the solenoid is de-energized, the pilot orifice (1) is closed and full line pressure is applied in the pilot chamber (2) through the bleed orifice (4) , thereby providing a seating force for tight closure. This type of solenoid valve requires a minimum operating differential pressure. We also produce pilot operated solenoid valves with a diaphragm mechanically connected to the plunger which may operate from zero up to its maximum pressure service. See all figures showing the various designs of solenoid valves direct and pilot operated as well as the different types of connections in order to obtain the functions as described above.