Shut off pressure
Shut off pressure
(OP)
can someone give me a definition of 'shut off pressure' on an automated isolation valve. The valve is spring return fail close butterfly valve.
Is the shut off pressure the maximum process line pressure where the valve is gauranteed to close and not to pass, or something else?
Is the shut off pressure the maximum process line pressure where the valve is gauranteed to close and not to pass, or something else?





RE: Shut off pressure
RE: Shut off pressure
Obtain valve torques to begin opening, begin closing and traveling. Verify the actuator torque against the valve torque in all situations. Assure that the testing is witnessed and results such as opening and closing times are recorded. The valve will perform better in a shop with no pressure applied than it will when installed. If you don't like the way it works in the shop -- you really won't like the way it works a year after it is installed.
RE: Shut off pressure
This is process shutoff pressure. It has nothing to do with sizing the actuator.
For the actuator, we size the actuator on 80 psig minimum (if you use less, say 70 psig, then you will need a larger actuator). On most I/A system, you will have around 100 psig for your valve.
Add to it the valve friction and then add 40% safety margin, you now have the torque requiremnt to actuate the valve.
This is also the spring's (on the spring return) torque requirement.
Should there then be a closing time requirement, then you may need to go even larger.
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RE: Shut off pressure
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