SodaStream PCP QEV Critique - All advice welcomed

[qevop]

Hey, I've recently started thinking about a PCP build.

I've done research but I'm obviously still a complete novice, so excuse the ignorance.

As the title suggests my idea is a PCP QEV 'rifle'.

This is a very simplified drawing, but gives the general idea. But I have some questions.

Is it possible to set a QEV like this? As in with the pilot port at the bottom, connected to a blowgun. The inlet port facing the cylinder and the exhaust port connected to the barrel?

My endgame is something like this: http://www.airgundepot.com/airforce-tal ... rings.html

Obviously not as complex, but that general sort of setup. Is my mockup close to being correct?

Any/all advice welcomed, thanks.

[Brian the brain]

I've never seen a QEV like that.

However...it is exactly like a modified solenoid valve.
They come in brass too...

[qevop]

Thanks for the reply Brian.

So you're suggesting a solenoid valve with pneumatic actuation?

Do you know of any write-ups that would shed some light on how to build one?

Could anyone suggest a pneumatic valve that is relatively compact and would suit my needs?

e.g. With the Inlet port at the back, Exhaust at the front and a Pilot at the bottom?

[Gnarp]

It depends on the pilot valve!
IF you switch place with the soda and the trigger you will have a single shoot gun! You need to put a spring behind the gev piston to be able to fill the gun. If you need multishoot you will ned a hammer valve to pilot or a solenoid!

Or just putt a 3 way valve to pilot and refil instead!

[Talk]

if this is the SV BTB talked about it'll need some careful modification

sv_fig1(1).gif (31.94 KiB) Viewed 4752 times

I know you want your final product to be like this but since youll need to mod the valve /(maybe even make your own valve), why not use the regular QEV setup

and you might be able to make your final product like this with a little carpenter work.

[Brian the brain]

It is one of the variants.

Easy mod: plug the pilot hole running from the solenoid to the out-port and replace the solenoid by a pneumatic valve, like a blowgun.

Or..strip the solenoid, but keep the armature and use a hose and clamp over that to hook up the blowgun.
This will then actuate the small pilot piston. A small spring could be used to have it reseat.
I suggest superglueing or soldering in a washer as a backstop so the piston doesn't end up in the hose.

And I believe this design should interest you: