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pop-off piloted sprinkler valve?
Posted: Thu Jan 17, 2008 12:30 pm
by jackssmirkingrevenge
would it work?
Posted: Thu Jan 17, 2008 12:32 pm
by SpudUke5
If the flow is enough, yea
Posted: Thu Jan 17, 2008 12:38 pm
by Hubb
Agreed with above. I don't see why it wouldn't work to make an automatic launcher, however, I would think it would need a fast filling air supply, such as a regulated CO2 / HPA setup.
I was looking through some old files the other day and Dr's hybrid had something like that on it. I don't know if it is exactly what you're talking about but it's close.
Posted: Thu Jan 17, 2008 1:15 pm
by bluerussetboy
i have an air compressor that runs nonstop. it has several "pop offs".
the first actuates at outlet pressure and bleeds off excess air until pressure drops below outlet pressure(ie. someone use a nailgun).
the second and third basically do the same thing just at different psi.
the second valve opens at 150 psi and closes at 135 psi.
the third(two actually, one on each tank) opens at 210 psi and have to be manually reset. it has happened twice since i've own this.
obviously the first one wouldn't work. you would get to a point and it would just bleed off the excess air while maintaining the pilot volume.
the second one would work better but once the pilot volume dropped to 135 psi the valve would close. is a 15 psi pressure differential enough let the sprinkler valve release enough air?
the third would work great. you would just have to reset it each time.
Posted: Thu Jan 17, 2008 2:03 pm
by ALIHISGREAT
can't see why not, is this for giving a 'pulse' air supply?
Posted: Thu Jan 17, 2008 2:09 pm
by Hubb
ALIHISGREAT wrote:can't see why not, is this for giving a 'pulse' air supply?
It's for giving something magical that he is probably working on to blow everything we know out of the water, which only he can do

Posted: Thu Jan 17, 2008 2:17 pm
by ALIHISGREAT
hubb017 wrote:ALIHISGREAT wrote:can't see why not, is this for giving a 'pulse' air supply?
It's for giving something magical that he is probably working on to blow everything we know out of the water, which only he can do

i just though that because he had been trying to make one for ages for an automatic he was making he may be looking at it from different angles

Posted: Thu Jan 17, 2008 2:58 pm
by Hotwired
I'd say it would.
A sprinkler valve is literally a barrel sealing valve but with the barrel twisted 90 degrees in the moulding so it's inline.
The difference between a pop-off QEV and a sprinkler would be that the QEV can reset quickly because the inlet air is right behind the piston but the sprinkler is reset by chamber/inlet air leaking behind the diaphragm.
Posted: Thu Jan 17, 2008 3:11 pm
by jimmy101
The problem with a pop-off valve is that as soon as the pressure drops below it's trigger pressure the pop-off starts to close.
Depending on the details of the pop-off, it may honk and be pretty ineffective at dumping the pilot volume quickly.
You might be able to hack the valve so that it stays opened once it is opened.
The pressure release valve from a water heater might work. They typically have a pretty big ID (1/2" or 3/4"?), open at something like 100 PSI, are fairly cheap, can be manually activated, and might be available at the local hardware store.

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For a ghetto pop-off you can just drill a small hole in the wall of a standard tire pressure gauge's.

Posted: Thu Jan 17, 2008 3:46 pm
by Hubb
Jimmy: That sounds like a better idea than using a standard pop-off. The hardware store I shop at sells them up to 1" and they come at different pressure ratings.
Posted: Thu Jan 17, 2008 4:12 pm
by jackssmirkingrevenge
I was thinking of making my own pop-off (JSR? standard parts?! lol) a la Btb, that should work a treat.
Posted: Fri Jan 18, 2008 12:18 pm
by jimmy101
Jack, any thoughts on how to keep the pop-off valve open and keep it from honking?
Posted: Fri Jan 18, 2008 12:49 pm
by Brian the brain
Guys...give it up...
A pop-off won;t cut it.
It resets at too high of a pressure to make the shots have any power.
The valve will close too quickly for this to be a succes.
There is a reason I made the Snapvalve!
Posted: Fri Jan 18, 2008 12:57 pm
by jackssmirkingrevenge
jimmy101 wrote:Jack, any thoughts on how to keep the pop-off valve open and keep it from honking?
basically by making something similar to what Brian did