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Max pressure of Ebay QEV/3 way

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Max pressure of Ebay QEV/3 way

Unread postAuthor: zeff » Thu Oct 31, 2013 3:03 am

I have ordered some of the cheap ebay QEV's and 3 way valves that are rated at max pressure of 0.8MPa. I found an 8mpa QEV but could not find a higher rated 3 way valve/blow gun/slide valve. I am going to use regulated CO2 at as high a pressure as the weakest component is capable however at the moment I am heavily constrained by the 3 way valve. The entire gun is silver soldered copper/brass and im looking for around 500psi or higher if possible.

Firstly does anyone have any online sources for higher rate 3 way valves?

Secondly, I have seen very similar looking 3 way valves used on other peoples creations that are said to be rated at much higher pressures than 0.8MPa. So my main question then is what are peoples experiences with exceeding the pressure ratings for the cheap QEV's/3 way valves off ebay? I think it would be likely the piston would fail before the body, has this ever happened to anyone and if so at what pressure in relation to the rated pressure?

Thanks.
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Re: Max pressure of Ebay QEV/3 way

Unread postAuthor: fenrir » Thu Oct 31, 2013 1:48 pm

Those ebay QEVs can withstand a lot of pressure -http://www.spudfiles.com/pneumatic-cannon-database/topic17298.html
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Re: Max pressure of Ebay QEV/3 way

Unread postAuthor: dart guy » Thu Oct 31, 2013 2:59 pm

I've read about 600 psi if you have a milled block, but the diaphragm may get warped. but also looking around may help get more accurate data.
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Re: Max pressure of Ebay QEV/3 way

Unread postAuthor: jackssmirkingrevenge » Thu Oct 31, 2013 3:13 pm

No record of a QEV case failure on the forum, but as was mentioned repeated use at very high pressures is detrimental to the piston/diaphragm.
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Re: Max pressure of Ebay QEV/3 way

Unread postAuthor: zeff » Thu Oct 31, 2013 3:47 pm

Great, thanks for the replies. I will def do a pressure test nonetheless before handling it at those pressures, just to be sure.
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Re: Max pressure of Ebay QEV/3 way

Unread postAuthor: Zeus » Thu Oct 31, 2013 10:00 pm

The rating will be 1.2 million cycles at 0.8 bar. It's like a car warranty, they mean it will NOT fail at that amount of cycles. It should be fine for 1000 at 400 psi or something like that.
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