Issue with GX Pump Air Filter

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FLgunner

FLgunner

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Mar 4, 2017
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Navarre, FL, United States
Today I went to fill an airgun and while the pressure was building according to the gauge on the compressor, the gauge on the gun was not moving at all! At 100BAR, I stopped the compressor and released pressure using the bottom bleed valve on the compressor.

I thin removed the GX Filter and just used a regular in-line filter and it filled the gun just fine., so it's not the gun, it's the filter!

I took the filter apart and everything looked fine, I tore down the top end, and it has a stack of belleville washers in the top of it that looks as if it must somehow regulate the output, but why would it be preventing air from exiting the filter?

Anyone else have this issue? Is this normal, and I just need to let it keep building pressure, or is something wrong?

Thanks...
 
Here are some pictures of what I found when I took the top of the filter apart...

IMG_5972.jpeg

This is what you see when you remove the largest nut.

IMG_5975.jpeg


This is the inside of where the smallest nut fits into the largest. The middle sized seems to be acting as a lock nut for the smaller one.

IMG_5973.jpeg


This is the belleville stack that's inside the smaller bolt.
 
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I just attached a block with a gauge on it to the end of the fill whip on the output of the filter. The gauge at the end of the whip did not move until the compressor gauge was close to 180BAR (2600 psi), then it let the air flow and I could see it quickly increase on the whip end gauge until the compressor shut off at 250BAR with the whip gauge showing 3600 psi. So, I guess it's working as it should, but that still seems a really high pressure before it let the air pass and leave the filter!
 
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FLgunner said:
It would make sense that the belleville stack is regulating the output of the filter, but I really don't understand why the output needs to be regulated.
Click to expand...
@FLgunner
The output holds pressure and does not release until approximately 1800-2000psi.
The reason for this is because the molecular sieve (water absorber) in the filter performs properly when under pressure.

just my 2%
Edward
 
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Avator said:
Ya know... this would also solve the problem with some guns not wanting to start filling unless they get a blast of air to seal them.
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Good point! I was filling my Huben K1 after replacing a few 0-rings, so it was empty. Of course, it doesn't have a conventional valve, so I'm not sure it would have made a difference with it, but I can see where it could help with more conventional airguns!
 
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FLgunner said:
Good point! I was filling my Huben K1 after replacing a few 0-rings, so it was empty. Of course, it doesn't have a conventional valve, so I'm not sure it would have made a difference with it, but I can see where it could help with more conventional airguns!
Click to expand...
Unfortunately, it will only help if it lets out a bit of a "dump" of air, as in much more than the compressor puts out at a normal rate. If the regulator is really precise in terms of what it passes, the flow rate at output won't be any higher than the flow rate of the compressor - and if to an empty gun, after the air leaves the filter at high pressure, it will immediately flash to the low pressure of the line to the gun which will also be at zero.

I expect it won't really help in this situation - a tank, even a small one, would do much better to help with this particular problem.
 
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FLgunner said:
Good point! I was filling my Huben K1 after replacing a few 0-rings, so it was empty. Of course, it doesn't have a conventional valve, so I'm not sure it would have made a difference with it, but I can see where it could help with more conventional airguns!
Click to expand...
I've noticed that mine opens slowly/mildly from what I can tell. It doesn't seem to burst into the gun??
 
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bchannell said:
I've noticed that mine opens slowly/mildly from what I can tell. It doesn't seem to burst into the gun??
Click to expand...

The output hose would add about 5cc's that needs to get filled first. The hysteresis seems to be 200 psi, so id guess the hose would hit 200 psi or below during the initial shock, the filter would close, then slowly raise from there in pulses.
 
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Jay308 said:
Nothing wrong with being cautious, we all forget how dangerous hpa can be. Glad it’s operating correctly, I’m going to buy a GX filter soon.
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How dangerous ?
this seems to be a recurring theme on here. are people getting hurt ? It would seem there would be many posts
relating to injuries or equipment damage. In my 9 months in this hobby heard a lot of DANGER DANGER.
I say prove it. Where are all the horror stories?
 
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blackdog899 said:
How dangerous ?
this seems to be a recurring theme on here. are people getting hurt ? It would seem there would be many posts
relating to injuries or equipment damage. In my 9 months in this hobby heard a lot of DANGER DANGER.
I say prove it. Where are all the horror stories?
Click to expand...
This is kind of a ignorant post, of course 4k psi is dangerous. Quality parts are engineered to be safe way beyond that but if parts are fatigued, broken or malfunctioning, caution should be used as hpa is dangerous.
 
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