Control Valves

In its present form, this question is too vague.

In general, you need to know how various types of control valves work, and what happens when they lose control power (whether electricity, air, or hydraulic). Depending on the design, such valves can be made so that when power fails, they wil "fail closed", "fail open", or simply stay in whatever position they are already in. You need to examine the process to figure out what should be done in the event of a failure, and select the valve accordingly.

The weight of certain components in the valve may allow it to open or close by gravity, or there may be a spring that opens or closes the valve if control power fails. There are too many combinations to describe in a short answer.

1)By Using Spring Diaphraghm Actuators

2) If Your Using Double Acting Actuator, Coz You will not be able to achieve Your Failsafe Position , Upon loss of Air Supply By providing Volume Tank You will be able to Stroke 3-5 Times + You can achieve Your failsafe Application

Regards

Jose