diaphragm valve / shut-off / air-operated / 2/2-way

This piston valve works with the pressure exerted by the pilot fluid, either water or air, on the piston within the cylinder. There are many control devices for turning off the pilot fluid, but the maker's recommendation is the JAKSA three-way control valve. This uses a spring force to turn off the valve. The entire operation begins with the activation of the three-way control valve, which applies the pilot fluid pressure to open the piston valve. The valve shuts off when the pressure from the pilot fluid stops. A pipe vent transmits the pilot fluid.

The maker's recommendation for pilot fluid is air (oiled). While water is an option, the calcium deposits and impurities in water can decrease the valve life. The pilot pressure needed for the value is dependent on the main fluid pressure, but has to be within 10bar.