motor operated valve - fire case

zh003 · Dec 3, 2008

Hello
We have in the project motor operated valves which are interlocked with pumps, compressors. They have to be closed in case of fire. Fluid is flammable and toxic. We have 3 pushbuttons ”Stop”- on the actuator, on the panel somewhere on the field, on the pump/compressor panel.
Please advise is it ok? What will happen in case of power loss? Can we however protect power cable, for example to bury it?
Thank you for advise
Zhan

JLSeagull · Dec 3, 2008

They have to be closed in case of fire.
Motor operated valves are not fail safe. The actuator stops in the last position upon loss of power. If you actually need a fail safe valve you need a spring. Piston operated ball valves with scotch yoke actuators are common for large valves. Rack and pinion actuators are common up to about 3 NPS.

JimCasey · Dec 3, 2008

There are a few failsafe electrically energized actuators.

They tend to be electrohydraulic.

One brand is REXA.
Another type: Smaller- rotary only- is the Worcester type 72.

Electric motor drives a pump to pressurize a cylinder. When power fails, a solenoid dumps the cylinder pressure and either a spring or a compressed gas accumulator drives the valve to a failsafe position.

roydm · Dec 3, 2008

Perhaps add a fire rated fusible link valve in series. They can also act as a manual isolation valve for maintenance purposes.
Hope this helps
Roy

zh003 · Dec 8, 2008

thanks!

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motor operated valve - fire case

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