Valve Type

[Drakkith]

Is there a valve that can be set to open to let hot gas out at a certain pressure, and then close once the pressure drops back down?

Edit: Sorry, I'm looking for a valve that will let the pressure build up to a high point, then open to release the gas until the pressure is released, then close again until the system builds up another cycle of high pressure. For example, I pump a cool gas into a closed space and heat it up to 500 degrees, at which point this valve opens up and releases the pressurized gas until the pressure is reduced to the original pressure of the cool input gas, then closes until the next cycle of air reaches 500 degrees.

[boneh3ad]

A regulator. They come in all shapes and sizes.

[Drakkith]

A regulator. They come in all shapes and sizes.

Whoops, i dont think i described what i needed very well. Lemme edit it.

[boneh3ad]

So a pressure relief valve (that is what it is called)?

[wmazz]

A solenoid operated valve is what I think you are looking for. There are many manufactures for this. look here (http://www.ascovalve.com/)

[boneh3ad]

Well, I suppose the question is whether or not you need the pressure to go all the way back down to the original pressure after it vents or just down to the threshold pressure for the valve. There is no need for a complicated and expensive solenoid valve if you just want your system to vent once it gets above a certain pressure and then when it drops back below that pressure to close back up.

What is the purpose of this valve? That would probably net you some better responses.

[Drakkith]

A solenoid operated valve is what I think you are looking for. There are many manufactures for this. look here (http://www.ascovalve.com/)

Thanks!

[DannyT]

I work at sea, and on our boilers we have these types of valves. We use them as safety valves to ensure the pressure inside the boiler doesnt get too high.

Ours are mechanically operated using a spring though. Spring is set to compress at a certain pressure, it is normally closed, pressure builds up, gets too high and the valve opens. Then when the pressure is back to where the spring will close, the valve closes.

Might be useful?

[Wetmelon]

I work at sea, and on our boilers we have these types of valves. We use them as safety valves to ensure the pressure inside the boiler doesnt get too high.

Ours are mechanically operated using a spring though. Spring is set to compress at a certain pressure, it is normally closed, pressure builds up, gets too high and the valve opens. Then when the pressure is back to where the spring will close, the valve closes.

Might be useful?

I think his edited post made it quite clear that he wants the valve to close again considerably below the threshold level (for whatever reason). Interesting that the boilers have this system, it must be quite large! Where does it vent to? Not the boiler room?

[DannyT]

Ahhh, My apologies.

Yeah we are talking big boilers, we need a fair bit of steam for all the heating systems for fuel oils etc. They vent to atmosphere usually via the funnel.