Hi Press Shut Down Valve

[Muleman]

We have several hundred pressure vessels that have pneumatic fail close inlet valves that shut in at high pressure. We'd like to add another level of protection so that if the current sensor doesn't react, an independent sensor would see the pressure, close the supply and bleed the diaphragm closing the inlet valve. Can anyone suggest such a valve?

 

[Ashereng]

Are you thinking along the lines of a HIPP system valve? If yes, chances are you will need pressure transmitters and shutoff valves.

Or, are you thinking of a high pressure pilot type of regulator? For this type, take a look at:

http://www.sur-flo.net/

Disclaimer: I am not associated with Sur-Flo in any way. We do buy their valves however, as a customer.

"Do not worry about your problems with mathematics, I assure you mine are far greater."
Albert Einstein
Have you read FAQ731-376 to make the best use of Eng-Tips Forums?

 

[JimCasey]

Throw a pressure switch on the vessel. Contacts open on increasing pressure at the setpoint. Wire this to a 3-way normally closed solenoid valve on the valve actuator, between the actuator and the positioner.

In normal operation the SV is energized and the positioner communicates to the actuator. On High pressure the SV is deenergized, isolates the positioner output and dumps the actuator air, failing the valve closed.

 

[Muleman]

One thing I didn't mention, we have no power, all controls have to be pneumatic.

 

[Ashereng]

The Sur-Flo doesn't require power.

"Do not worry about your problems with mathematics, I assure you mine are far greater."
Albert Einstein
Have you read FAQ731-376 to make the best use of Eng-Tips Forums?

 

[JimCasey]

Fairchild make snap-acting relays that sense the process pressure and enable or disable your valve accordingly.

Your post is unuasual in that I am frequently told by the customer that he has all the electric I need, but no pneumatic supply available.