Reversing Control Valve Actuator Fail Safe Mode :
I want to reverse the “fail safe” mode of a Masoneilan (MIL) make control valve from “fail open” to “fail close ” and vice versa. Please suggest.
If the actuator model is 37/38 series, it is not possible because model 37 is fail open and model 38 is fail close. If you have 37 series you need to order 38 series.
But if the actuator model is 87/88 series, it is possible to change the fail safe mode easily in the field from fail open to fail close, by changing the spring and diaphragm direction installation order.
Actuator series 87/88 are field reversible.
Also Read : Valve Leakage Types
Pneumatic Spring Diaphragm Actuators
Actuator model is 87/88 series
Actuator model is 37/38 series
Parts List & Materials of Construction :
Image Courtesy : Masonelian