Metal slider valve design and construction, help.

[)DEMON(]

I want to make a slider valve for and piston valve exhaust. I liked the design of clides semi auto paintball gun, the main part is the slider valve: http://www.spudfiles.com/forums/viewtopic.php?t=160& . I don't need a gas through slider valve, I only need it to exhaust. I have a design shown below that is made out of a few various bits that fit together and should keep pressure.

These valves have good characteristics, like they are compact and open and close fast.

clides semi auto has a constant air supply with a compressor, does his slider valve completely seal? I don't have machening equipment but I still should be able to get one working.

So has anyone got any ideas on the construction and design of this valve? Brian?

[POS]

Nice design indeed. Only one problem I think, I guess the holes and the O-rings won't go together. I think the holes will block the slide due to the O-rings which will be forced in by their own tention. (if you know what I mean ...) Maybe cuts in the lenght of the pipe will help solve that problem. I like that concept a lot.

The part between the holes and the endcap could be filled up, to reduce the pilot volume.

Maybe I make one of those some day.

But.. Instead of the combination between copper and PVC, I will only use PVC

Look at my pic :

1= 32 mm PVC
2= 40 mm PVC
3= 40 to 32 mm PVC reducer ring
4= O-ring
5= long cuts instead of holes
6= 32 mm endcap

This is easier to make, and I guess it will work bether, cause of the cuts instead of the holes. The hard thing will begetting the O-rings in place, and cut out the reducer rings so the O-ring fit in them.

[schmanman]

Is it for the exhaust on your shotgun? the design looks like it would work just fine. pos, I don't get what you are saying. (Nice diagram, looks like that design would work too.)

[POS]

it can be used as a pilot valve of any pneumatic. You could get wider pipes to get a better flow though.

What exacly don't you understand ?

[Brian the brain]

I have made a similar valve.I used a copper T, with reducers on both ends.I put two short pieces of pipe in the reducers, sticking into the tee a bit.I placed rubber hose over the ends of the pipe ( on the inside of the tee) and slid a 12 mm pipe with a hole in it through the two 15's.

It sealed very well thanks to the hose, but it was kinda difficult to open it fast.

[)DEMON(]

Only one problem I think, I guess the holes and the O-rings won't go together. I think the holes will block the slide due to the O-rings which will be forced in by their own tention. (if you know what I mean ...) Maybe cuts in the lenght of the pipe will help solve that problem.

I did realize this problem as the o rings will be forced out of place and into the holes somewhat and be unable to get back onto position. I could cut slits into the pipe with the thin cutting disk on my angle grinder. I also think I will make a larger on out of pvc for now, it will be better for tinkering with. I get the same size pipe you have POS. In your diagram it looks like you have designed o ring groves that will have to be cut with a lathe. You need 40mm links to go over the 40mm pvc befor you can put the reducers in.

I propose you cut the reducer in half so you can put and o ring between the two peices. I think you will also need to wear down the inside diameter of the reducers a bit with sand paper.

I am a little doughtfull if the valve will seal perfectly although I guess you could make it do so. Brian, could you please make a simple diagram?
What size copper did you use? I tested and oring on copper pipe to see if it slid alright, I added grease and it worked with no effort.

[killagorrila99]

Looks fine, It should work great.

[POS]

Demon, i didn't actualy made this valve (yet) I just tried to design one, taking out the possible problems in the first design. PVC is easier to handle then copper. So I would make it out of pvc. And of caurse, it will need links, unless you use pipe with inner diameter of 40 mm. It exists. I found it on a Dutch site. Store isn't far away from me (92 km)

[)DEMON(]

Links will work fine.

I am aware you didn't make this valve but I must have posted in a way which made you think differently.

What size o-rings do you suppose I should get? If I get tight ones, smaller than the outside diameter of 32mm I might run the risk of them forcing themselves into the slits. If I get large ones or the same size the valve might not seal. Should they be thick or thin?

They will slide with no problem because I will use grease.

[schmanman]

go for slightly under size. at least It should seal that way.