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Triggered burst disk

Post questions and info about pneumatic (compressed gas) powered cannons here. This includes discussion about valves, pipe types, compressors, alternate gas setups, and anything else relevant.
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Unread postAuthor: Hotwired » Thu Aug 20, 2009 10:42 am

mikemurph wrote:Whats a presta bike valve?
[/quote]

http://en.wikipedia.org/wiki/Presta_valve

I use them because the track pump I use gets a better grip on them than schrader valves.
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Unread postAuthor: THUNDERLORD » Fri Aug 21, 2009 9:56 pm

The presta valves leak much less than the shraders according to the bikey pro shops.
(the one's where you pay a lot of $$$ to look like a Homo in tights). :P
If the triggered BD is pre-filled like the link in OP (original post)...and the trigger valve leaks, bad.

Second thought though, prestas and shraders have low flow so for something big a ball valve should trigger it faster.
(faster triggering, not valve speed though).
*edit: :oops: Ooops! if a ball valve is used for trigger, there'd be a gaping hole between chamber and barrel. :oops: Nobody must read my replies!!! :( *

...So in your opinions triggering it the way i originally stated is the easiest way to do it, but i still want to know about the ballvalve before the burst disk
=====[O]=======( l )=====
burst disk ball valve chamber=>
<=barrel ...


It could work OK (better than BV alone).
But if the burst-disc ruptures before the ball-valve is fully open, it will still have flow restriction, (since the burst-disc ruptures from pressure and not volume)...
unless the ball-valve is spring-loaded or your burst-disc has just the right burst characteristics. (tricky to obtain).

I was toying with a burst-disc on a PVC barrel in front of a sprinkler valve.
It definately improved performance.
I just put blue painter's tape on the barrel, cut excess tape with a razor around barrel, and really jammed it into a coupling on the front of sprinkler valve...fun fun, one shot the entire barrel shot out, made a BLAM, but the tape was unbroke (so I grabbed the barrel and man-handled it on next shot...BANG!!) :P

The advantage of spring loaded BV over sprinkler valve is the rating and rating of pipe although IDK how much shock PVC comparable to it's rating. (1" sch 40 nsf is rated to 450 psi IIRC).

I was daydreaming up a multi-barreled, triggered burst disk design with one electronic trigger and solenoids to press each presta valve (or all simultainiously)...It involved a rectangular detergent jug with a nice shaped handle to encase it in. :roll:
Cool concept! 8)
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