mlw19mlw91 (Customer) asked a question.
1/4" 3-port 110VAC solenoid valve that has one port normally open and one port normally closed?
I'm working on replacing a check valve with a solenoid valve, but I need for A on one side to be normall closed with port B on the other side, and normally open with port C on the other side. All of the valves I can find just list normally closed or normally open and they don't specify really if port A to B is normally closed while port A to C is normally open for exhaust.
Please help!
edit: I want pressure from a pump feeding a tank. I want to use it as a check valve, and an unloader valve. So the inlet, or port A will be connected to the output from the pump, and when energized it will connect the pump to the tank, when not energized it will unload the pump.
With the AD offering (AVS) based on THIS SHEET, your "A" port is "A", while port "B" is "P" leaving port "C" as "R." The one thing I'd point out is an AVS valve spool will not shift without sufficient air pressure at "P" (spec sheet shows minimum 20 PSI). I would finally note that if your application involves the check valve being part of safety, using a solenoid valve not specifically designed for that purpose is not advisable.
Ok, let me see if I have this straight, you want a 1/4" NPT valve that when not electrically energized, say ports A is open and feeding a cylinder, but B is closed to pressure but is open to exhaust. When you energize the valve, port A switches pressure to port B and A then goes to exhaust? Essentially you would do this to use a single valve to control a 2 way air cylinder or similar.
If so, here is what you are looking for, though the smallest of the 1/4 NPT offerings, you will have to determine the CFM flow requirements.
https://www.automationdirect.com/adc/shopping/catalog/pneumatic_components/pneumatic_solenoid_directional_control_valves_-a-_accessories/5-port_(4-way),_2-pos.,_body_ported_-z-_manifold_(avs-5,am_series)/avs-5212-24d
^ almost. I want pressure from a pump feeding a tank. I want to use it as a check valve, and an unloader valve. So the inlet, or port A will be connected to the output from the pump, and when energized it will connect the pump to the tank, when not energized it will unload the pump.
This should work? AVS-3212-120A
Will you meet the minimum 20 PSI at port "P" at all times? If not, what you want to do will not work. A different solution, (and I've done this before), use an air piloted valve as your check valve, and use a separate valve that sees proper air pressure all the time to operate it. So go with this AVS-5242 as your 3-way (you'll have to plug one port because it has 4-ports) and use this AVP-31C1-120A to operate it.
You will need a constant air supply to the AVP valve, but with it operating the AVS valve, no worries about pressure at the ports of the AVS.
Todd has pretty well covered it. The solution I offered is not even close. Lets be clear, are you talking about air or a liquid as your medium through the valve?
I will have a constant 100 PSI at shut off of the pump at the P port, that is correct. Can I use the AVS-3212-120A?
Just to confirm, the P port is the port that is open when the coil is energized?
When energized, P opens to A.
When de-energized, P is blocked and A opens to R.
You will not want to use the typical internally piloted 3 way valve, as it sound like you will be using it as a selector/diverter valve, you'd need to use the A port as input, R port as normally Open and P port as normally closed, however the internal pilot supply comes off the P prot so that won't work, one needs either a direct acting or an externally piloted valve.
I don't know that Automation Direct sell anything suitable, the only liquid rated valves I see are only 2 way.
Can you use a mechanical check valve for the check function and a 2 way valve teed off between the pump and the check for unloading?
I can do that, except I'd want a normally open valve that closes when energized in that case since it's much easier to use the compressor's pre-existing switch in this case.
I guess I could also use a 2 position relay and use a dual coil solenoid switch for the air? That shouldn'thave issues with the coils moving it in both directions, correct?