what is the meaning of reverse action and forward action of
control valve...




Answer Posted / saravanan

Direct acting valve
Air to close -- Spring to open --- Failed Open (FO)
(increasing air pressure pushes down diaphragm and extends
actuator stem)



Reverse acting valve
Air to open -- Spring to close --- Failed Close (FC)
(increasing air pressure pushes up diaphragm and retracts
actuator stem)

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