What is a Solenoid Valve
We have many years experience with Solenoid Valves and wanted to answer this basic but often asked question
A solenoid valve is an electromagnetically operated valve. As a current is passed through the coil, the plunger is lifted up and out of the valve seat, thus opening the valve and allowing fluid pass through. When the current is stopped the plunger drops back down into the seat therefore closing the valve. Solenoid valves come in normally open and normally closed versions and they come in 2-way and 3-way options. They are also available in manifolds to allow for many more inlets and outlets. The valves rely on the electro-magnetic field created by the solenoid coil to draw the plunger out of its seat. Direct acting solenoid valves are where the plunger directly opens and close the valve, pilot operated solenoid valves are where the solenoid controls a pilot orifice which then opens and closes the valve. Pilot operated valves have a diaphragm with two small holes on the diaphragm one in the centre and one the outside (the pilot orifice). The hole in the centre allows the fluid above the diaphragm and whilst the outer hole is blocked which builds up pressure and as a result it keeps the valve shut. When a current is passed through the coil the pressure from above the diaphragm is released which allows the valve to open.
Watch this short video on how they work: Solenoid Valves