Purification tower loses pressure over time

[flymolo]

Hi,

I have an older model alkin w31 compressor. When I fill a tank with it I typically leave the pressure in the purification tower (and the whip), and just bleed off the water separator.

I noticed that over the course of several days the air will leak out of the purification tower and fill whip. I can't seem to figure out where it's leaking however, so I changed the check valve that sits between the water separator and the purification tower, and I changed the PMV. At first it seemed like it would hold pressure indefinitely but now it no longer does.

Is it an issue if the purification tower sits unpressurized for periods of time in between uses?

 

[clownfishsydney]

My Bauer Junior II and many others that I have read of in this forum do the same thing. Not a problem over 26 years.

 

[wdeutsch]

My Bauer Junior II and many others that I have read of in this forum do the same thing. Not a problem over 26 years.

I don't doubt your experience at all, as you have had your compressor for a LONG time and have clearly figured out what does/not work. So, the following question comes from me trying to adjust my understanding of how things work, not questioning yours.

If the purification tower loses pressure (down to atmospheric, eventually), doesn't that mean it's open to exchange with ambient air - even if only a tiny bit? If so, won't that then allow humidity into the chamber and then saturate the molecular sieve, meaning it can't keep air dry when filling?

I've been stressing about a similar thing on my Hypress compressor, and would love to know if I can chill TF out about it.

 

[admikar]

While in theory it is possible for outside air to enter the tower, I don't think that leak is large enough to cause any real concern.

 

[clownfishsydney]

I don't doubt your experience at all, as you have had your compressor for a LONG time and have clearly figured out what does/not work. So, the following question comes from me trying to adjust my understanding of how things work, not questioning yours.

If the purification tower loses pressure (down to atmospheric, eventually), doesn't that mean it's open to exchange with ambient air - even if only a tiny bit? If so, won't that then allow humidity into the chamber and then saturate the molecular sieve, meaning it can't keep air dry when filling?

I've been stressing about a similar thing on my Hypress compressor, and would love to know if I can chill TF out about it.

It's higher pressure air escaping. Once it is equalised with outside, then very, very little exchange will occur. I can tell you that the molecular sieve is still 50% good when I replace it.

 

[rob.mwpropane]

I leave my tower under pressure so that when the air enters in it already has the humidity removed. I won't leave it at 4k, I'll drop it to around 2k. On my setup there aren't that many fittings. Is it so hard to find the leak?

My pmv leaks through to the fill whip, so I just leave them turned off.

In the grand scheme of things I don't think it's the end of the world for a personal setup. I have a friend that has the same compressor as me and he has to bleed his tower down after every fill. He just changes filters more often.