New WBl idea. Instead of using a sprinkler valve, you might want to consider use of a QEV:
http://www.airlines-pneumatics.co.uk/we ... de=S070139
A 3/4" QEV has more flow than a 1" Sprinkler valve, opens even faster, and based on UK costs, costs about the same as a 1" sprinkler valve.
It requires no electric parts and is completely mechanical in it's operation.
Water Balloon topic
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joannaardway
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"Over the hills and far away, she prays he will return one day. As sure as the rivers reach the seas, back in his arms again she'll be." - Over the Hills and far away, Gary Moore
"So many people have come and gone, their faces fade as the years go by. Yet I still recall as I wander on, as clear as the sun in the summer sky" - More than a feeling, Boston
"So many people have come and gone, their faces fade as the years go by. Yet I still recall as I wander on, as clear as the sun in the summer sky" - More than a feeling, Boston
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Silence
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joannaardway
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Quick Exhaust Valve.
A QEV should out do a modified sprinkler valve, both on flow co-efficent (about 25% higher) and opening time (50%-100% better). The typical rating on one of these is about 150 psi, against the 125 psi of a sprinkler valve.
As a very rough explanation, a QEV is basically a piston valve operated by venting the air space behind a "special" piston.
It's normally used to trigger pneumatic cylinders, for better actuation times.
I'm linking to some topics on another forum about QEV triggered launchers.
http://www.uksgc.co.uk/forums/index.php?showtopic=273
http://www.uksgc.co.uk/forums/index.php?showtopic=191
http://www.uksgc.co.uk/forums/index.php?showtopic=306
These are all low bore launchers (the first two are 20mm launchers, and the last started as a 13mm bore, but was changed to 20mm).
However, there should be no issues with using a valve like this on a 2" or 3" bore wbl.
You may remember me mentioning that my twin was building a new launcher that would chuck 20mm steel ball-bearings a 1/4 mile.
That's also going to be a low bore launcher, but using two of these valves for incredible performance levels (including firing frozen grapes at 2/3rds of the speed of sound).
However, with a single valve, a heavier projectile and a higher bore, muzzle velocities will not be that nasty.
A QEV should out do a modified sprinkler valve, both on flow co-efficent (about 25% higher) and opening time (50%-100% better). The typical rating on one of these is about 150 psi, against the 125 psi of a sprinkler valve.
As a very rough explanation, a QEV is basically a piston valve operated by venting the air space behind a "special" piston.
It's normally used to trigger pneumatic cylinders, for better actuation times.
I'm linking to some topics on another forum about QEV triggered launchers.
http://www.uksgc.co.uk/forums/index.php?showtopic=273
http://www.uksgc.co.uk/forums/index.php?showtopic=191
http://www.uksgc.co.uk/forums/index.php?showtopic=306
These are all low bore launchers (the first two are 20mm launchers, and the last started as a 13mm bore, but was changed to 20mm).
However, there should be no issues with using a valve like this on a 2" or 3" bore wbl.
You may remember me mentioning that my twin was building a new launcher that would chuck 20mm steel ball-bearings a 1/4 mile.
That's also going to be a low bore launcher, but using two of these valves for incredible performance levels (including firing frozen grapes at 2/3rds of the speed of sound).
However, with a single valve, a heavier projectile and a higher bore, muzzle velocities will not be that nasty.
"Over the hills and far away, she prays he will return one day. As sure as the rivers reach the seas, back in his arms again she'll be." - Over the Hills and far away, Gary Moore
"So many people have come and gone, their faces fade as the years go by. Yet I still recall as I wander on, as clear as the sun in the summer sky" - More than a feeling, Boston
"So many people have come and gone, their faces fade as the years go by. Yet I still recall as I wander on, as clear as the sun in the summer sky" - More than a feeling, Boston
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joannaardway
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Quoting some figures off spudtech for a 3/4" Pneumatically modded sprinkler valve Vs a 1/2" QEV:
With a 40 CI chamber, 5' CPVC barrel, 100 PSI, shotgun slugs for projectiles (425 grains) the average muzzle velocities were as follows:
3/4" Sprinkler valve: 388.3 fps
1/2" QEV: 517.3 fps
So the QEV results in 33% more performance (129 fps more).
With regards to a 1" Sprinkler vs. a 3/4" QEV, I have no figures, but the greater efficency of the QEV's should allow use of lesser pressures for the same effect (meaning less effort pumping up the launcher)
With a 40 CI chamber, 5' CPVC barrel, 100 PSI, shotgun slugs for projectiles (425 grains) the average muzzle velocities were as follows:
3/4" Sprinkler valve: 388.3 fps
1/2" QEV: 517.3 fps
So the QEV results in 33% more performance (129 fps more).
With regards to a 1" Sprinkler vs. a 3/4" QEV, I have no figures, but the greater efficency of the QEV's should allow use of lesser pressures for the same effect (meaning less effort pumping up the launcher)
Last edited by joannaardway on Tue Aug 22, 2006 7:03 pm, edited 1 time in total.
"Over the hills and far away, she prays he will return one day. As sure as the rivers reach the seas, back in his arms again she'll be." - Over the Hills and far away, Gary Moore
"So many people have come and gone, their faces fade as the years go by. Yet I still recall as I wander on, as clear as the sun in the summer sky" - More than a feeling, Boston
"So many people have come and gone, their faces fade as the years go by. Yet I still recall as I wander on, as clear as the sun in the summer sky" - More than a feeling, Boston