Page 480 - Industrial Ancillaries 2020 Catalogue (Sterling)

12
Process Valves
Valve Basics
Direct Acting Solenoid Valves Solenoid Valves without Differential Pressure
(direct acting or indirect acting with forced lifting)
Process Valves
480
PP AA
Valve closed
This type of valve is actuated entirely by the solenoid force. The plunger with a seal acting as the main closure device is forced directly onto the valve seat by the uid pressure and closing spring. The valve is opened directly by the solenoid force only.
Valve closed
The force produced by the solenoid plunger, which is mechanically coupled to the main closure device, opens this type of valve.
The sequence starts with the solenoid opening the pilot seat. This relieves the pressure on the main closure device, bringing it into balance so the solenoid force can lift it into the open position.
When the pilot seat is closed, bleed ori ces allow a force to build up on the closure device that pushes it down into the closed position on the valve seat.
These valves are preferred for use where the differential pressure is very low or zero.
PA
Valve open
PA
Valve open