The Internals of a QEV.

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Mitchza89
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Tue Apr 21, 2009 12:04 am

Well, Mitch has finally got himself a QEV. Mitch being Mitch, I had to open this baby up and see what was inside. I was always curious how it was different to any piston valve I've built. Exactly the same but just.....perfect. These things really are beautiful In their simplicity. Well worth the money.

Enjoy!
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Lentamentalisk
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Tue Apr 21, 2009 12:13 am

I just love that nice flat black, sexy box QEV! It is so sleek!
I think you have already posted this elsewhere, but where did you get it?
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Mitchza89
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Tue Apr 21, 2009 12:15 am

I would have posted a while ago about the website it was on. I only got it a few days ago :D.

For a 1/2'', it really doesn't have the flow I thought it had. I don't know if all QEV's are like this, but the port holes are about 8mm in diameter which doesn't at all worry me, I use 6-8mm ammo anyway.
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frankrede
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Tue Apr 21, 2009 12:16 am

Lentamentalisk wrote:I just love that nice flat black, sexy box QEV! It is so sleek!
I think you have already posted this elsewhere, but where did you get it?
Thats what I was thinking, that style of QEV is jus begging to be beautifully integrated into a stock and a set of weaver mounts put on top of it.
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Mitchza89
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Tue Apr 21, 2009 12:19 am

You read my mind :D. I'm going to make a semi-auto polished brass and gloss black gun. I hope to use my explosive pop off trigger for it.
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jackssmirkingrevenge
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Tue Apr 21, 2009 12:48 am

Mitchza89 wrote:For a 1/2'', it really doesn't have the flow I thought it had. I don't know if all QEV's are like this, but the port holes are about 8mm in diameter which doesn't at all worry me, I use 6-8mm ammo anyway.
That's something people using QEVs should take note of. If you're using this particular with a 1/2" barrel, you're only getting 40% of the flow you'd be getting from full 1/2" porting like say with a co-axial piston.
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Mitchza89
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Tue Apr 21, 2009 12:53 am

Yeah exactly right. I had a feeling this would be the case so I'm glad I got a 1/2''. The flow it has is perfect for what I need.

What worries me is that the piston is like that of a sprinkler valve, just made out of rubber. A lot of QEV's are being taken to pressures that could be bad. There is no way anyone would take a basic rubber diaphragm sprinkler valve up to 400psi when it's only rated to 120-150, so if these are rated the same then why do people take them so high?
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Lentamentalisk
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Tue Apr 21, 2009 1:09 am

Because QEVs tend to be made out of metal, which people are betting their money on holding out past the point at which the piston fails, whereas in a sprinkler valve, the case is made out of plastic, which quite possibly could be weaker than the diaphragm, and nobody wants to be digging little pieces of sprinkler casing out of their aorta.
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Mitchza89
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Tue Apr 21, 2009 1:12 am

Yeah fair point. I wonder if all other QEV's have the same piston though. I generally can't see any of them being mate out of a metal/alloy.
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Carlman
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Tue Apr 21, 2009 1:13 am

That is one nice looking but strange qev...

My 1/4" SMC qev from over here with the sand gropers has 10mm flow yet ports to 6mm...

I love the look of it though mate!
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Mitchza89
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Tue Apr 21, 2009 1:23 am

Aw bugger it. Sounds like I got a little ripped off :D. Ah not to worry. I'm very happy with it.
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Carlman
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Tue Apr 21, 2009 2:53 am

I payed 50$ for mine though
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jackssmirkingrevenge
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Tue Apr 21, 2009 2:58 am

Carlman wrote:I payed 50$ for mine though
you could have cast one out of epoxy for less than one tenth of that ;P
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Carlman
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Tue Apr 21, 2009 3:50 am

serviceable?
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SubsonicSpud
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Tue Apr 21, 2009 4:00 am

That is the same style QEV I am using, from www.bellpro.net

I have been using the 1/4 sized one and it also has the same sized porting, the piston they use in the 1/4 and 1/2 I believe is the same. As for the pressure rating, it will have no problem going up to 400psi, the casing is very solid. The piston on mine has not got any damage on it yet, and it has been cycling 10 times a second at up to 15-20Bar in my QEV Popoff setup. After seeing how simple the layout is, I would not think it would be much trouble to make one with only a drill press and a block of plastic or aluminium. The only difficult part would be the piston, which is probably available as a spare part.

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