Technical information


Functions
Our solenoid valves operate on an all-or-nothing principle. They therefore possess two distinct states, which are (1) - when the coil is activated by an electrical current, and (2) - when the valve is resting (without electricity). Valve functions are defined from the resting position.

The solenoid valves direct acting or pilot operated may have two functions:

Normally Closed (NC)
A solenoid valve is normally closed (abbreviated - NC) if no flow cross the valve in its resting position (with no current on the solenoid contacts).

Example of 2/2 way normally closed solenoid valve

Example of 3/2 way normally closed solenoid valve

Please note that in the case of 3-way solenoid valves, port A is open to port R which, for example, enables the valve’s single-action cylinder to be exhausted to atmosphere.

Normally open (NO)
A solenoid valve is said to be“normally open” (abbreviated NO) when it enables fluid to pass in its resting position (with no current on the solenoid contacts).

Example of 2/2 way normally open solenoid valve

Example of 3/2 way normally open solenoid valve

A specific choice of entry ports can change a valve’s function. However, since balanced-force calculations take rebound effects, coil effects and the effects of pressure exerted on the seal into account, the performance of an NC valve fitted in an NO position would be reduced. In this configuration it would be better to choose a universal solenoid valve.

Universal (UNI)
A solenoid valve is said to be “universal” (abbreviated UNI) when it enables several different functions as a result of specific orifice connections. Universal solenoid valves are specially dimensioned for giving optimum performance in all configurations.

Example: "Normally closed" pneumatic connection

Example: "Normally open" pneumatic connection

Example: "Selector" pneumatic connection where the pressure "P" is directed either to outlet "A1" or outlet "A2"

Example: "Mixer" pneumatic connection where either pressure "P1" or pressure "P2"are directed to outlet "A"

Latch or bi-stable
We manufacture solenoid valves designed for applications where reduced energy consumption is the determining factor. For these applications a short electrical impulse enables the solenoid valve to be opened or closed, and thanks to the residual effects of a permanent magnet this is sufficient for maintaining the valve in a particular working position with no electrical energy consumption.

A short impulse of inverted polarity ensures the valve’s return to its previous position. Electrical power consumption and heating are almost negligible.