Answer / sridhar

if the flow must be maintained in process line, we can use
the double acting control valve. for example,if there is a
purging system for any process control,even if the signal
fails and air fails, the valve should be in same poistion
to maintain the flow in the pipe line for process safety.

Answer / carl_ellis

Part of your problem is your terminology.

Valves are chunks of machined metal and elastomers, valves
are not single action or double action, the actuator that
moves the valve stem is.

So your Google search should be for double action actuator,
which will provide you an answer.

Carl Ellis
Measure First

Answer / afroz

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