Valve is controlled by compressed air acting on piston in the cylinder.
Valve is kept open by the spring force.
When pilot pressure is applied the valve closes. When pilot fluid is shut off the valve opens. Pilot fluid is exhausted through pipe vent.
*Prices are pre-tax. They exclude delivery charges and customs duties and do not include additional charges for installation or activation options. Prices are indicative only and may vary by country, with changes to the cost of raw materials and exchange rates.