Couple of pnuematic cannon questions

[frogy]

Yay, my turn to right something really long

A sprinkler valve is a Diaphragm based valve with 3 "areas" the inlet port, the area above the diaphragm, and the area sealed off by the diaphragm...

When you fill your chamber it causes air to go into the inter port, but the air doesn't flow down the barrel because of a diaphragm that is held down by a spring... The air in the inlet port goes through an "equalization hole" and flows into the area above the diaphragm so the PSI in the area above the diaphragm and in the inlet port are the same...

And to fire the valve you rapidly drain the air that is above the diapragm so the diaphragm moves up because the pressure in the inlet port cant "equalize" fast enough, so it pushes the diaphragm and flows to the area that was sealed off by the diaphragm and out the barrel...

It's really 200x more simple than it sounds

Here's a sequence diagram of an UNMODDED sprinkler valve...
http://www.spudtech.com/content.asp?id=21

When yo mod a valve, you normally just put a larger exhaust valve that drains the area that is above the diaphragm... The most common valve being a blowgun.

[crcowboyfan]

I like to plumb my fittings into my cannon to reduce the leaking and or flying fittings problem. Here is how I mounted my pressure gauge. I did the same with my Schrader (tire) valve.

<a href="" title="Photo Sharing"><img src="http://static.flickr.com/53/167592506_35ea7df606.jpg" width="500" height="354" alt="Gauge"></a>

What parts would I need to get to a 1/8" female threaded adapter from 2" sch-40 pvc?

[SpudStuff]

2" coupler, 2"x1/2" Spigot x trd bushing, 1/2" x 1/8" threaded bushing, 1/8" guage

[pneumaticman]

i have the sam question as crcowboyfan. i was also wondering if there was an even better valve than a sprinkler valve that is also cheaper than a sprinkler valve too.

[frogy]

i have the sam question as crcowboyfan. i was also wondering if there was an even better valve than a sprinkler valve that is also cheaper than a sprinkler valve too.

If their was, don't you think we would use them?

Make you own valve or buy a sprinkler valve....

[carlbelcher]

A sprinkler valve opens much faster than you could ever open a ball valve. There are a number of tutorials on how to pneumatically modify sprinkler valve including my new "No Drill" (shameless plug) mod. By modifying a sprinkler valve you do two things, one you convert the valve from electric to pneumatic actuation, this means that you don't have to carry around batteries, and two the modification allows the valve to open even faster.

[trae08]

yes it does its a lot faster to open unless u put a hydrolic ram to open ur ball valve like they did on spud chucker 1. go to the how to section it will tell you how to mod ur valve.