I guess from this question you've not used a HiPAC? There's no way for the pressure to get back to the pump, unless the fill poppet seal is leaking,
With that big spring pushing on the check valve, I would doubt you could bleed it that way.... not sure, but that would be my guess....Bob
No. The big spring is capable of pushing a couple more pounds per square inch than atmospheric pressure, just enough to keep the seal closed initially when filling from scratch. And no, that's not how this valve works. No bleed is possible without physically slamming something into the poppet rod. Probably not a very nice way to do it...
The microbore hose from the pump has to be at slightly higher pressure than the fill level in the HiPAC.
No, that's the fill port. The big spring forces a couple of washers forward toward the Foster nipple, keeping the poppet in place when there is no pressure.
Quote from: Gerard on September 16, 2015, 03:40:13 PMNo, that's the fill port. The big spring forces a couple of washers forward toward the Foster nipple, keeping the poppet in place when there is no pressure.So what does the other end look like? Is it like the inlet one-half and it screws into the 2240's exhaust half of the valve, or is it some kind of blind hole that mates with the stock 2240 valve? It's not designed to pressurize the tube, I assume.
Can you humor me? (Or anybody else who has a HiPac) Put a little (more) air in your Hipac and then ever so slightly open the bleeder and see if it doesn't drain. As soon as air starts coming out of the bleeder do not open it any further, just leave it where the air is slowly coming out.
I am greatly disturbed by Gerard's report that a HiPac, properly installed, was able to retain pressure in the tube with a normal 22XX valve and no added seal (except some grease) between the HiPac and the tube.... It makes no sense to me, as that is part of the safety supposedly designed into the HiPac system, that any leak in the seal would never be a problem, as the pressure would leak out past the valve and through the (unsealed) front threads before the pressure could even build up.... I had (and reading this, still have) concerns that the pressure would not necessarily bleed off quickly enough to prevent the single 6-40 valve screw used in a 22XX from shearing, but everyone reassures me this is not the case.... Yet here we have somebody stating otherwise.... It does make me wonder if I was correct in my initial feelings.... and very glad that Alex eventually recommended replacing that screw with an 8-32.... In Gerard's case, it would appear he was lucky he had three of them, or could have had a similar failure to that in this thread.... with the valve coming out the back of the gun.... The difference is, that in his case (and according to his retelling of it), he used the HiPac the way it was intended....Bob
I find it VERY difficult to believe that unsealed straight threads held pressure without leaking...make that "impossible to believe".
Okay. Just did that with my 2240 carbine. Filled to 2,200psi (it was sitting at 1,500psi) then opened the bleeder on my FX pump. A small initial blast of air came out, just the air in the hose, then the handle slowly dropped with a trickle of air hissing out the bleed hole from the air left in the pump handle. The gun is still at 2,200psi, as expected. Somehow your brain has got something turned around backwards maybe. Been there, done that, more than enough times so that I know better than to poke fun, as hey, it happens to everyone. But imagine what would happen if when you opened a 'bleed hole' on a bicycle pump all the air escaped, that is, with a presta type valve? (Not the Schrader type as those rely on a small pin pushing the valve poppet open during the fill, so of course they'd dump all the air.) The presta valve is basically the same as the valve at the Foster fill nipple on a HiPAC. The poppet closes after every pump stroke. There is nothing left open until you exceed the contained pressure with the next stroke. It's not like my Pardini cylinders - they're more like a Schrader valve, in that a pin pokes the valve in the cylinder open on the final turn of the cylinder when mounting it to the pump. So if I open the bleed screw the Pardini cylinder will just dump all its pressure. And I must unscrew VERY quickly at a certain point in the dismounting or I'll do exactly the same, thanks to that little pin poking the poppet open.
How does the poppet "close" after each stroke? When pumping and your pump reaches the HiPac pressure do you hear the valve opening? You should. Do you then hear it open on each successive stroke? You shouldn't. The pressure (as long as it's above the pressure of the spring) is equal on both sides. When you quickly open the bleeder valve the lower pressure in the hose causes the valve to close.
I'd love to see what sort of test rig you plan, though trust that you'll be safe about it.
nevermind, there's the problem.......shouldn't open it enough to make a "Blast", that defeats the purpose. Just might have to buy one to prove I can do itHow does the poppet "close" after each stroke? When pumping and your pump reaches the HiPac pressure do you hear the valve opening? You should. Do you then hear it open on each successive stroke? You shouldn't. The pressure (as long as it's above the pressure of the spring) is equal on both sides. When you quickly open the bleeder valve the lower pressure in the hose causes the valve to close.Nothing backwards here in my head, sorry to say.
How did you seal the forward grip frame threads in the tube? Guys normally use a disco front half on the valve or something similar, but that's obviously not readily usable with a hipac....Maybe you had TWO sets of unsealed straight threads sealing pressure....this is even more unlikely to be honest.What was in that build for a striker spring and valve stem at the time and is it possible you shot it right to empty before filling it that last time?
Cannot bleed off a system that has a spring loaded check without manually opening the check.Al
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