FAQs - Pressure
Can you apply back pressure to the outlet side of an EH Series valves?
The EH series valves are designed to seal with inlet pressure greater than outlet pressure. The EH series valves will only seal in one direction.
Explain the minimum pressure requirements of the EH40 (50psi) and EH50 (100psi).
The minimum differential pressure requirement is for opening and closing. The higher inlet pressure is used to unbalance the axial forces on the piston and drive it to and away from the orifice.
Differential pressure does create a proportionally large holding force on the piston once closed. In other words, the more differential pressure, the better the seal.
Why can't an EH30, 40 or 50 valve be operated by DC power and 10,000 PSI pressure?
Higher differential pressure requires more force from the solenoid to lift a pilot pin and initiate the opening process. The DC coils do not have "in-rush" current, and hence do not initially generate as much initial force as the AC coils. Lower allowable differential pressures for DC coil valves is the result.