Quick exhaust valve from Humphrey, what's the problem?

[Leonard]

Hello!
I just recently ordered a SQE1 super quick exhaust valve from Humphrey.

http://www.humphrey-products.com/hpwpc. ... SQE106.pdf

For a strange reason i realy though they would work just like sprinkler valves. Strangely this does not seem to be the case! As soon as air pressure is applied on the Input, it leaks out to the output...?

Also, blown air in the output will exit trough exhaust port... How am i supposed to attach this kind of valve?

Thanks for the help guys, i'll be sure to post some nice videos of the finnished launcher to pay back for your help!

[Carlman]

the port labeled EXH is your barrel, IN is your chamber and OUT is pilot

[POLAND_SPUD]

As soon as air pressure is applied on the Input, it leaks out to the output...?

Also, blown air in the output will exit trough exhaust port... How am i supposed to attach this kind of valve?

I've never had this valve but what you wrote is basically what a QEV does

Check wiki on QEVS --->
http://www.spudfiles.com/spud_wiki/index.php?title=QEV

EDIT
uhmm I've just checked your link... that's a qev valve uhmm sorry there was no QEV in the title of the thread so I thought that you reffer to something completely new (like ASCO valves)

[Gippeto]

http://www.humphrey-products.com/hpwpc. ... SQE106.pdf

In is the fill/pilot

Out is the chamber

Exh is the barrel

[Leonard]

In is the fill/pilot

Out is the chamber

Exh is the barrel

V.S.

the port labeled EXH is your barrel, IN is your chamber and OUT is pilot

... Humn ... I smell contradicton ^_^ I think Gippeto is right, and i think i should have figured that out myself... But i may be wrong.

EDIT : Thanks, i tried and it worked. You guys are great.

[psycix]

It doesn't matter how its called, but since its actually a barrel sealing piston valve in some sort of tee, the chamber port is the one thats on the side.

[socoj2]

1. Pressure is applied to inlet it flows to the outlet Or the place where your chamber is at.

2. When the pressure from the inlet drops below that behind the outlet. The flow is redirected from Outlet to the Exhaust.

You can mod QEV, so that you can fill from the OUTPUT and just pilot from the input as well.

[Leonard]

You can mod QEV, so that you can fill from the OUTPUT and just pilot from the input as well.

Is that so? I'v lurked the forums for quite a while and never saw a thread about modified QEVs. I would be curious to learn how this is possible if you could throw in some infos or link about that.

[POLAND_SPUD]

it's simple - you have to make a hole in the piston... it lowers performance as some air from chamber gets to pilot side when you pilot the gun.

[hoarp001]

The seal on the piston in the valve body was so tight on my 3.5in piston i had to drill a hole too. I put a one way valve into the piston body to help it suck back and it worked really nicely

[POLAND_SPUD]

pistons on most QEVs that I've seen act as oneway valves.. therefore you have to make a hole in the piston to let air flow in both directions - so that you can fill from 'chamber' side...

[psycix]

Besides an hole in the piston,
You might need a spring if you want to fill from the chamber side.

But its unreliable, you might screw up your QEV and on top of it, it lowers performance due to air slipping trough the hole.
Just fill it from the pilot.

[Leonard]

Yup, i guess i will just fill from the pilot side, drilling a hole in a 1/8 inch wide diaphragm looks a little too dangerous to me.

Im quite surprised by the flow of the QEV, blowing trough the QEV from chamber side to barrel side needs no more force than blowing trough the actual 1/4'' barrel, meaning that the 1/8'' QEV will not chock the flow from chamber to barrel, am i right?

[psycix]

No

On high velocities the 1/8" QEV will block flow for a 1/4" barrel.

[Leonard]

But :

Blowing trough the QEV from chamber side to barrel side needs no more force than blowing trough the actual 1/4'' barrel

This should mean that the size of the inner cavities of the QEV where the air goes through and the barrell diameter are similar, right? So the flow of both parts should also be similar if the diameter of both parts are similar. Well, the air in the QEV needs to push the diaphragm, so that might make the difference you're talking about.

You're also stating "High velocities", do you mean that on higher pressure the QEV is more likely to chock flow? It is quite possible, i am not familiar with higher pressure, but im wondering how that can happen.