SpudFiles

first, if you try to make this and it fails it is not my fault.

if this does work this will allow for an inline pneumatic piston valve. thr piston will move down when the valve is triggered

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What makes you think that the piston will not just go straight down? even gravity would have enough force to let it drop before the bottom section has enough pressure to hold the piston up. Secondly, is the air from the fill valve can go into the bottom section it could also get int the barrel unless some equalization holes were drilled in the piston. Third, in order for the piston to seal it will need O-rings. I don't recommend you try this design, it will just waste parts and time.

blackhawk13 wrote:first, if you try to make this and it fails it is not my fault.

if this does work this will allow for an inline pneumatic piston valve. thr piston will move down when the valve is triggered

There are some motorcycle carburators that use that design. Under pressure the sealing of the piston becomes an issue. (do a top down diagram) the piston has to be considerably larger than the pipe it blocks. The seals are hard to get to seal under pressure. The edges when open provide turbulance. It's ok for low pressure applications without any seals such as a carburator throttle, but it's pretty useless in a high pressure application.

its a lot like a gate valve but pneumatic actuated, why don't you make a fill and pilot one valve?. i think the barrel sealer is better

Much too hard to seal well. Though it could perhaps be adapted to an automatic mechanism with a pop-off valve and spring to pilot it.

It's sort of similar to clide's old design of an inline piston valve

http://www.spudfiles.com/forums/stv-ver ... 16879.html

sorry i didnt get to finish my post last night. i just found out about this thing called sleep

this valve would be filled throught the trigger valve first (the bottom part). then the main air chamber and the top pilot chamber. the piston would completely seal the tube its in. sorry i didnt draw that well. jmadden91, i never saw that so sorry for copying that.

my design has a few advantages over a normal piston valve:
1. there is no pilot hole so you will not loose any air pressure when firing
2.it is an inline and could have more power than a normal piston valve
3. because the pilot is seperate you can use lower psi than your main chamber to pilot it

Its not mine mate and your not copying anything its just a coincidence. Just saying its got potential :thumbleft:

ok. so other than the problem sealing it what do you think? will it work?

How about this(and that is the basis of my semi auto design really) use your design just trigger it manually...:D

Looks a bit unnecessary. Also a little complicated to get to work right. It would be better to use a sprinkler valve at pressures under 120 PSI.

SEAKING9006 wrote:Looks a bit unnecessary. Also a little complicated to get to work right. It would be better to use a sprinkler valve at pressures under 120 PSI.

but i am talking about using 500+ psi

maybe its just me, but it seems like 500+ psi pushing on 4 square inches (2" barrel) would need a whole bunch of vaccum to overcome the friction. i had some too-much-friction problems on my regular T piston, and that had a whole bunch of extra engineering thrown at it. the fix wasn't too bad, just grabbed a tube of lithium grease

It would be better to angle the seat and piston and not run it across the tee.

Just add a guiderod ( off center) to ensure the piston lines up with the 45 angle..

And voila.
Give it extra travel and you'll have a 100 % flow, inline cannon..

that would work. the type of valve i was imagining would not have a pilot hole in the piston. if i filled that valve through the pilot and main chamber then that might work