Need Qev Help

[dudeman508]

I looked all over the internet for instructions on how to make a qev ad i found to 2 videos on youtube but they were in french and it looks kinda like a piston valve but i still dont fully understand it, can anybody help

[MrCrowley]

A homemade QEV is a piston valve more or less.

A QEV as most Spudfiles members know it, is a metal valve usually bought from www.mcmaster.com. They are known to perform better then sprinkler valves of the same size and have been taken to pressures of over 500 PSI.

QEV stands for Quick Exhaust Valve and usually come in two forms:

The Shuttle:


Which uses a small piece of plastic as the piston and is mainly found in the UK.

The American QEV (not sure what to call it)


I can't remember if these use pistons or diaphragms. These are usually only found in America.



There are a few pictures of the internals of these QEV's on the forum somewhere.

Pretty much the QEVs made in those videos are just small bore, high pressure piston valves. Like piston valves, QEV's have three ports.
Barrel, chamber and pilot. On the valve they are labled as something else like EXH, IN and OUT if I recall correctly, I can't remember.

Here is an American QEV being used on a cannon:
http://www.antennalaunchers.com/tblpics/DSCN4627.jpg

It's a 3/4" QEV which can be bought for about $20US on McMaster and will out perform a 1" sprinkler valve.

[frankrede]

I have found "Shuttle types" here in america from Fastenal.

http://www.spudfiles.com/forums/a-canno ... 12400.html

[psycix]

A QEV is a commercially made barrel sealing piston valve.
Check out the "piston valves explained visually" thread in the howto section if you want to know how it works.

[Hotwired]

Furthermore you don't make what we call a Q(uick)E(xhaust)V(alve) round here, you buy them.

The valves you make are called after the way they work: barrel sealers, chamber sealers and co-axials.

A QEV is what the commercially made ones are called.

Of course they operate in the same ways but it's just a way of differentiating them.

The french video clip is a barrel sealing piston valve.

[daberno123]

@Frankrede

Is this the QEV you used on your "Cannon For A Friend"?

http://www.fastenal.com/web/products/de ... ku=0443031

That would be great if it is, because using the store locater I've just realized there's a store 10 minutes form me.

[VH_man]

haha theres a store 10 minutes from me too!!!!

:smilebox:

(i just had to im kinda happy right now.......)

[iisthemuffin]

Wow. There are two that are about 15 minutes away from me. I may have to go purchase one of these.

Very good selection.

[frankrede]

@Frankrede

Is this the QEV you used on your "Cannon For A Friend"?

http://www.fastenal.com/web/products/de ... ku=0443031

That would be great if it is, because using the store locater I've just realized there's a store 10 minutes form me.

Yep, thats the one!