Do check valves work?

[pOrk]

So far, my experience says no. I have used tried 2 diaphragm type and two different mechanical check valves on my on-board air system that is COMPLETELY air tight except for the air compressors with no luck.

The first SMC check valves I used worked great for about 2 weeks, then I think from them heating up and cooling down the rubber diaphragm loses its sealing capability and allows for a slow leak through the compressor and out the intake filter. Not so good. These are rated at 200 PSI, pictured here:

http://www.suicidedoors.com/images/products/SMC_Check_Valve.jpg

The mechanical ones I bought locally and still do not seal properly. I tried cleaning / lubricating the ball and spring, still no dice. These are rated at 4000 PSI, and my system operates at just under 140 psi so that isn't the issue. Mechanical check valve pictured here:

http://www.piermont-valve.com/photos/ngrv.jpg

Where can I find one that works? So far I have spent $40 on check valves that do not function properly, its driving me nuts.

[Breecher_7]

We have them on alot of the pneumatic systems at work. Im gonna say yes they do.....

[kornholio788]

I used those smc check valves for a long time when I was bagged and they worked great. I loved them.

[wrath]

What are you using it for?

A spring holding a piece of plastic over a hole is all it takes. That's all the ones that are used in factory car suspensions.

You could probably get something from a tractor-trailer shop. I don't know if there are any places like that around here.

[95 TA - The Beast]

Doing the air system on the T/A, I realized that a LOT of pneumatic products out there perform for only a short time...

About the only luck I have had is with Air-Ride Technologies products (for air valving), and with some serious industrial products (read: quite expensive)...

Now, if you are positive the system on the other side of the checkvalve is 100% sealed (do a test, install a fixed valve and a pressure gauge on that side, pressurize and check a day later), then spend the money once on some quality checkvalve and be done with it...

I redid my entire system twice to find out the fittings on the airbags themselves had a leak, fricken drove me nuts for over a month, until I did the proper testing of all the systems components individually...

[pOrk]

I know for a fact that my air system is sealed up tighter then my ass hole, I have never had this problem before.

I am using two ViAir 380 compressors that go to a 3 way t, from the 3 way t they go to a 1/2" check valve, and from there a 4 foot stainless leader hose to a water trap, to a 5 gallon stainless tank.

The SMC check valves are 15 bucks each, and the 4000 psi ones are 8 bucks each. The check valves that come with the viair compressors work great for the first year, then fail and its a ***** trying to get them replaced by SMC hence me trying to find another one to make it work.

When I hard plumb the comps to the tank, they only leak I have is from the back feeding through the compressors. I put a plug in the intake port on the compressors and was leak free, thats how I know its the check valve.

[wrath]

Looks like decent ones are $15-25 from MSC Direct.

[Russ Jerome]

You need automotive tractor protection valves, some are piloted to 60psi,90 psi or 0.
A zero psi protection valve is a one way check valve, any semi dealer will have them and made by Bendix, may have some here at home. For that matter brass one way [pop off valves like we use for turbos are mechanical steel balls and seal 100% forever. graingers catalog, popoff valve, adjustable, they have them on display by the brass.

What is you peak and minumum pressure your using?

[pOrk]

I run a 140 psi pressure switch, so when the tank reaches 140 the compressors turn off. They turn back on when the pressure drops below 105 psi.

[Russ Jerome]

You can use any check valve from semi trucks, piloted or no
piloted even brake prop valves from air/abs systems will work.

Graingers may have something more user freindly in size but
I'll look in my garage or at work thurs and see if I can find a
sample (read: free stuff).

[BadAzzGTA89]

I agree with Russ 100%:thumbsup