Water removal recommendations for Shoebox compressor?

[Taso1000]

Hello All,

I finally got around to creating a remote mounting solution for the plumbing after the Shoebox.  I wanted to take the weight and vibrations off the 1/8 npt threads of the vertical cylinder block, I'm not sure of the proper name of the part.  There is now a high pressure swivel and a microbore hose that feed the new high pressure drying setup.

I have attached pictures of the new high pressure air drying configuration.  The electronic pressure cut off switch was removed from the cylinder block plumbing and is in the new group now.  I do need to extend it's wires but I will do that when I move everything to the garage and mount the remote group.

I did implement Mr. Sterne's suggestion to up the pressure maintaining valve setpoint to higher that the final fill pressure.  The Shoebox compressor is rated to 5000 psi so that is where I set the pmv to.  Everything before the pmv will be pressurized to 5000 psi.  There is a bleed off drain at a drip leg to remove accumulated moisture.

On the 2 outputs of the pmv I have installed the pressure cutoff switch and the feed to the cylinder I am filling.  The pressure cutoff switch is set to 4500 psi.  Before the output quick disconnect foster fitting I installed a new, one way, check valve as a safety measure.  This is so that when the cutoff stops the compressor, the pressure in the bottle doesn't bleed back through the compressor.  Plus I don't want to lose the compressed air in the cylinder that took hours to compress in case of a failure upstream.  There is another drip leg and bleed/drain off this branch as well.

When I first changed to the new 5000 psi pmv setpoint I did have some pressure, ~300 psi, bleed over to the 4500 psi side.  At first I was concerned.  But then after I thought about it I realize that this is such a small volume of higher pressure air.  The test setup was basically the air volume in the Shoebox, 2 microbore hoses and the pmv, check valve and plumbing.  If a carbon fiber cylinder was connected this small amount of 5000 psi bled air would be unnoticeable, so I think it is safe to disregard.

Since I was not able to detect moisture in the previous setup with the moisture indicators before and after the Alpha filter, I did not include the moisture indicators or the Alpha filter in this configuration.  The new 5000 psi setpoint of the pmv should wring out more moisture than the previous 4000 psi setpoint.

I am filling a cylinder as I type and everything is going good.  No leaks with the soapy water check.

I think this is how the setup will stay.  Unless I read about a new idea to try out.   

Thank you to everyone that followed along and for all your help and suggestions!

Taso

[Hangtown-Shooter]

 Interesting setup Taso, looking forward to hearing your impressions once you’ve had time to run this new configuration for awhile!
 
 I went bit overboard on my (pre-ShoeBox) filtration myself, but I have not invested in any for high-pressure side... yet 

[Taso1000]

Thanks Dave!

So far I've filled one 30 minute scba tank from 1700 to 4500 psi and a 2nd 30 minute scba tank from 3900 to 4500 psi.  So far so good.  I started to try to fill a Great White tank I recently bought from empty.  The motor was hot (normal hot) and I was tired so I figured I'll leave it for tomorrow.

I think I'm going to add a bigger fan on the back of the case to cool the compression cylinders and make a cowl or something to direct the air out through the motor.  The motor is vented front and back so I just need to seal the back of the Shoebox to the front of the motor.  I'm hoping this will help in cooling the motor as well.

The new high side system fills up a lot quicker now from empty.  It's mostly because the Alpha filter is gone and I think I had a small leak or two before.  I had so many plumbing connections and I think I was also leaking out the front cylinder block 1/8 npt connection.  The weight of the previous high side setup would loosen and rotate that connection over time.  I couldn't tighten it without taking it all apart because the pressure switch was also mounted there.  It all needed to be re-done.

As for better moisture removal?  I didn't have the resolution in the indicator disks to tell how much below 10% humidity the previous setup performed.  Since the pmv is set 1000 psi higher, theoretically the compressed air should be drier than the previous setup.

My Shoebox is a factory upgraded Max.  I run it at around 85 psi to keep stress and temperatures down, or at least I hope the lower pressure helps.  Heat is bad mkay?   

Since I have multiple scba cylinders I'm not in any hurry to fill.

Let me know if you have any more questions and I will be happy to answer.

Thanks,

Taso