Issue with GX Pump Air Filter

[FLgunner]

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...

 

[JimNM]

AFAIK and from what I have witnessed- the GX filter does not pass air out until it reaches about 1800psi built up in the filter.

How far did you let the pressure build in the filter? My GX4 takes about 120 cycles before the filter starts to pass air.

 

[FLgunner]

I stopped it before it hit 150 BAR. Maybe I have never noticed this because I'm typically topping off airguns, so I just never noticed. Today I was filling an airgun that was empty, so starting out at zero on the gun gauge and started freaking out when the compressor is showing 100 -150 BAR and the gun is still showing zero!

 

[FLgunner]

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

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

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.

This is the belleville stack that's inside the smaller bolt.

 

[FLgunner]

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.

 

[FLgunner]

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!

 

[JimNM]

Thanks for the photos. I think the filter media absorbs more humidity from high pressure air. So forcing the air into pressure before allowing any quantity to pass makes sense. Otherwise you would be passing water until both the gun and the filter hit the working pressure.

 

[SilentSquirrel]

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.

@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

 

[1900colt]

Yep, takes 1800 to 2K PSI before that will let pressure go to the gun.

It's one of the stand out features of that filter.
You will also need to release pressure from the brass valve at the top to let air out of the line.

 

[Avator]

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.

 

[Mike_Lenardon]

I'll be 3rd in line,
Mine opens up between 1800 and 2000 psi

 

[FLgunner]

Thank you everyone for all the comments and reassurance my filter is working as it should! A simple explanation on their website as to how it actually works would have gone a long way toward relieving my stress and paranoia! LOL! I can get really jittery around HPA, so knowing all is working as it should helps me a lot!

 

[FLgunner]

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.

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!