Normally closed solenoid

[driftin]

I'd like to use a normally closed solenoid as an emergency shutoff on a water line. I would have a float switch and/or water sensor that would cut the power to the solenoid, closing it in case of overflow/spill.

My question is, will there be a problem keeping the solenoid powered open 24x7? Since this solenoid would only close under an emergency condition, it would normally be energized open. Would this work ok? Any decrease in solenoid life to be expected?

 

[rustybucket145]

Are you wanting it to shut off a saltwater line or freshwater line?

 

[rbursek]

Selenoid valves work with a spring and a magnetic shaft, you can get failed open or closed depending on how the spring works, failed open, spring opens valve the magnet when energized over powers the spring to close, failed close works just the opposite.
Bob

 

[driftin]

Right, I want it to fail closed. But my question is whether there will be any longevity or reliability problems if the solenoid is energized 24x7. This will only be de-energized in event of an accident.

 

[rustybucket145]

But my question is whether there will be any longevity or reliability problems if the solenoid is energized 24x7

That's why I asked if you were valving salt or freshwater.....

 

[driftin]

Sorry, missed that. It will be on a RODI water line.

 

[rbursek]

Get a good quality one and test it on a regular basis, but it could always fail when you need it. Why not go with a spring open, power to close, down side is in a power failure it would not be able to close, but the spring would not be in a compressed position all the time.
Bob

 

[Frick-n-Frags]

the good industrial ones are made for longeterm heavy use. you just have to make sure you get it with a rating for whatever liquid you are running through it (salt water obviously is way more corrosive that fresh water) If you are using on the RO raw water supply line, you can even use metal ones, which once you start shopping, you will see this could be a good advantage in the $ department

ASCO, they make good solenoid valves


that's good logic for sure: fail to safe state

seriously, thats how conveyors and other automated process stuff gets layed out.

 

[driftin]

I will look for ASCO valves later today, thanks for the tip.