Buschjost’s Pressure operated valves are actuated by pressure acting on a piston or diaphragm. When pressure is connected to port “Z”, the valves open or close according to type. A separate 3/2 pilot valve, or occasionally a 4/2 or 5/2 pilot valve, is used to supply pressure to port “Z”. The pilot valve is mounted either directly on the actuator or remotely.
In the basic position the depressurised chamber of the actuator is open to atmosphere via the exhaust port of the “pilot valve”. When the solenoid of the “pilot valve” is energised the exhaust port closes and fluid passes through the pilot valve, building pressure in the chamber.
The pressure builds up under the main piston/diaphragm and the valve spindle lifts the valve seal off the valve seat and continues until the valve is fully open.
When the pilot valve is de-energised the supply pressure is shut off and the air pressure within the chamber vents to atmosphere. The piston/diaphragm now returns under spring pressure, the valve seal covers the valve seat and the valve closes and remains closed under spring pressure. In some versions (closing with the flow) the fluid exerts a pressure on top of the valve seal that assists the closing process.
When pressure is connected to port “Z” the valves open or close according to type.
A separate 3/2 pilot valve is used to supply pressure to port “Z”, it is mounted either directly on the actuator or remotely.
Please click on the link for more information on the Buschjost range of pressure operated valves. Alternatively, please call our technical team on (+) 44 0870 803 2001.