Ballvalves and High Pressure Air, risk ? oh also Diagphrams

[al-xg]

EDIT: copied from 10th post

Oh and does anyone know what the approxiamte safety margin on a diapragm QEV is ? I'd imagine it varies a lot, but any feedback would be helpful.
(the valve in question is a 3/4" with a metal body, rated at 175psi, just wondering how far someone has pushed this type of valve?)

What could go wrong with a ballvalve like the one below if used at high pressure (850psi)?

Its a 1/8" mini ballvalve.

I can't think of any failures apart from: leaking, the threads breaking or the body exploding. But I'd imagine much higher pressure would be needed to do so.
People have used regular balvalves to those pressure before (there was even one on JSR's latest full auto prototype), I'd just like to know your thoughts about this one.

[Hotwired]

Not a lot, possibly leak.

[MountainousDew]

Not a lot, possibly leak.

Yeah, if I understand right it would push the metal "ball" up against the rubber gasket that is surrounding it.

[al-xg]

Right, thats what I thought.
Its just that i saw some ballvalves especially rated for 1000psi, and wanted to make sure.

Oh and Hotwired, I seem to remember you using a similar valve on Copperhead Prime, is there any flow restriction or is it the same diameter all the way through ?

[MountainousDew]

Right, thats what I thought.
Its just that i saw some ballvalves especially rated for 1000psi, and wanted to make sure.

Well if they are rated that high, they probably have a herder gasket around the ball.

[Hotwired]

Yes I did use the same ball valve on my pilot setup.

I can honestly say I have no solid idea anymore.

Mine was a 1/4" BSP one connected to 8mm (6mm ID) copper tube and I'm pretty sure the porting was no less than 6mm.

[jackssmirkingrevenge]

People have used regular balvalves to those pressure before (there was even one on JSR's latest full auto prototype), I'd just like to know your thoughts about this one.

Yep, that was a regular 1/2" ball valve, no pressure ratings, seemed perfectly fine, though in fairness it hasn't seen a lot of long term use.

[ralphd]

I use valves such as these in my industry which is Air Conditioning. Especially with new refrigerants such as R410a the pressures are 500+. The danger really is leaks which are costly due to their prices and fines for depleting the ozone. I have found valves that you would think are metal because they are silver but are chrome coated plastic or something like that.

[SubsonicSpud]

I have used valves like that up to about 600psi without any issues.

SubsonicSpud

[al-xg]

Mmm I'll just make sure they are made from metal then.

Oh and does anyone know what the approxiamte safety margin on a diapragm QEV is ? I'd imagine it varies a lot, but any feedback would be helpful.
(the valve in question is a 3/4" with a metal body, rated at 175psi, just wondering how far someone has pushed this type of valve?)

[twizi]

so ure gonna use a 1/8bv to actate a 3/4 youll get noticble diffrance in 1/4 or 1/2 but its up to you

i use my 1/4 diagram to 500psi somtimes, it might go higher,500psi is as hi as my reg goes

[al-xg]

Thanks for the information twizi.

The 1/8"BV aren't for piloting, and won't even be used on the same setup as the Diaphragm QEVs.


If any one else also uses diaphragm valves at higher than rated pressures please let me know ( I guess the closer to 3/4" the better)