Water removal recommendations for Shoebox compressor?

[Taso1000]

Hey John!

Sorry I didn't respond quicker.  Did a 3 day weekend for spring fishing. 

It's ok and I'm jealous!   

I too had wanted to leave the Shoebox pressurized when not in use but I guess it wasn't designed that way from the responses I received.

As for molecular sieve:  all I have read is that it works best at a minimum pressure at 1590 psi. 

I honestly can not say there is anything wrong with your idea.  I'm still trying to understand all this hpa stuff.   

The downsides that I can think of are possibly pushing any condensed water and contaminated air back through the molecular sieve and system.  It could be possible that the reverse flow can damage or unseat orings?  And lastly you'd be wasting precious filtered air!    

I've tried looking at scuba compressor system layouts and trying to figure out, by searching online, what and why they are doing stuff.  All of the schematics I've seen have the pmv pretty much last.  I have read they set pmv's in the 2000 - 2300 psi range.  I have seen they use a lot of one way valves. 

I think I know the reason why their pmv valves are set lower.  There are scuba tanks that are only filled to 2400 to 2640 psi.  So the pmv has to be set lower to fill these lower pressure cylinders.

Thanks!

Taso

[RobertMcC]

My little mini gold filter that goes on my end of the whip seems to be working well. And now since I can get dryer air. There is less moisture in my low pressure system.  Just using 10 to 5 micron water separator higher than the compressor, and than going into a desiccant filter.

[Taso1000]

Update!

Hi All,

I added another pmv in my loop to see if I can condense more water out before it reaches the Alpha filter.  I still need to set the pressure point once the thread sealer cures.

By next weekend I should have the pressure point set and hopefully catch some water as I have a cylinder almost at 3000 psi that needs topping up.   

Once my testing is done I think I will remote mount the pmv and Alpha filter because I don't like how everything is hanging of the original Shoebox outlet.  The new pmv has mounting holes that will be a big help.

Thanks,

Taso

[chwillbill68]

Update!

Hi All,

I added another pmv in my loop to see if I can condense more water out before it reaches the Alpha filter.  I still need to set the pressure point once the thread sealer cures.

By next weekend I should have the pressure point set and hopefully catch some water as I have a cylinder almost at 3000 psi that needs topping up.   

Once my testing is done I think I will remote mount the pmv and Alpha filter because I don't like how everything is hanging of the original Shoebox outlet.  The new pmv has mounting holes that will be a big help.

Thanks,

Taso

Taso what kind of thread seller do you use?  I have a couple small leaks and need something other than T-Tape.
Thanks Bill C!

[Taso1000]

Bill,

I use Vibra-Tite 444 threadsealer and their 612 primer:





Thanks,

Taso

[chwillbill68]

Bill,

I use Vibra-Tite 444 threadsealer and their 612 primer:





Thanks,

Taso

Thanks Taso!

[RobertMcC]

Taso are you losing CFM/PSI with all those filters that the air gotta go thru?

I'm trying to find out if 14mins is avg time. To top up a 330cc ( 20ci ) tank from 100 to 200 bar?

I normally only have 3 filters setup, but I brought down my larger 8 gal compressor. That normally in the garage and has a 4th filter on it.

[Taso1000]

Robert,

I'm positive all my filters have some restriction but I am regulating the output pressure to the Shoebox at about 90 psi anyway.  The membrane drier has a flow rate of 0.353 cfm.  So that is the limiting component in my air supply.  It's the best for my needs.

Off the top of my head, I think my compressor kicks on at 95 psi and shuts off at 125 psi.  It has a flow rate of 1.10 cfm @ 90 psi. 

I removed the output regulator and connected the yellow hose with a quick disconnect on the end.  The first regulator is set at 140 psi to protect the first 3 filters.  The regulator before the membrane drier is set to 120 psi to protect it.  Then the last regulator is set to 90 psi to feed the Shoebox. 

There is a purge on the membrane drier that is a constant leak to discharge the removed moisture of .088 cfm.  The Shoebox uses < .2 cfm.  So I only need < .288 cfm from the compressor to run my setup.  The compressor supplies almost 4 times what I need.

I hope that answered your questions.  If not, let me know and I will clarify.

Thanks,

Taso

[AlanMcD]

Adding plumbing and filters after the Shoebox won't lead to any loss in flow rate through the compressor.  As Tsao was indicating, that is fully defined by the pressure and temperature (together yielding the density) of the air charge, as the pump will run at at constant speed regardless of the pressure on the output side (I have verified this).

What the plumbing and filters will do is increase the amount of air that needs to be compressed  in order to get air into your tank - and all of it will be vented to the atmosphere when done (or will likely leak out over time) and thus could be viewed as "wasted run time" in filling our tanks.

That is why I do all my drying before the air enters the Shoebox - all I "waste" is the air in the fill whip, and I use that to purge the base of the Shoebox after pumping by always venting from the Shoebox itself rather than the fill whip (something that I think is good for the Shoebox too).

[RobertMcC]

Robert,

I'm positive all my filters have some restriction but I am regulating the output pressure to the Shoebox at about 90 psi anyway.  The membrane drier has a flow rate of 0.353 cfm.  So that is the limiting component in my air supply.  It's the best for my needs.

Off the top of my head, I think my compressor kicks on at 95 psi and shuts off at 125 psi.  It has a flow rate of 1.10 cfm @ 90 psi. 

I removed the output regulator and connected the yellow hose with a quick disconnect on the end.  The first regulator is set at 140 psi to protect the first 3 filters.  The regulator before the membrane drier is set to 120 psi to protect it.  Then the last regulator is set to 90 psi to feed the Shoebox. 

There is a purge on the membrane drier that is a constant leak to discharge the removed moisture of .088 cfm.  The Shoebox uses < .2 cfm.  So I only need < .288 cfm from the compressor to run my setup.  The compressor supplies almost 4 times what I need.

I hope that answered your questions.  If not, let me know and I will clarify.

Thanks,

Taso

Thanks I did a test. Tried my little 1.5 HP 2 gal compressor. That I got tuned that kicks on at 90 PSI, takes like 20 seconds to fill to 120 and runs for 3 mins 40 seconds before it kicks back on again. That did 14mins 44 seconds to fill the same tube from 100 BAR to 200 BAR. Compressor only kicked on 4 times.

So the 2HP and 8 GAL compressor isn't really that much better. So back to the garage it will go. Only nice thing about that, it didn't kick on as much.

[Taso1000]

Robert,

You could always add a portable 5 gallon tank to your system.  I tried this but don't know if it was beneficial.  You will have more time before the compressor kicks back on but it will run longer to fill the additional 5 gallons.

My concern with my CAT compressor is that if the compressor runs longer than designed it could overheat the pump heads.  Also the hotter pump head will create hotter air.

I could measure the compressed air temp over a half hour both ways.  I didn't feel like doing that so I removed the 5 gallon tank from the loop and abandoned the idea.   

Taso

 

[RobertMcC]

Robert,

You could always add a portable 5 gallon tank to your system.  I tried this but don't know if it was beneficial.  You will have more time before the compressor kicks back on but it will run longer to fill the additional 5 gallons.

My concern with my CAT compressor is that if the compressor runs longer than designed it could overheat the pump heads.  Also the hotter pump head will create hotter air.

I could measure the compressed air temp over a half hour both ways.  I didn't feel like doing that so I removed the 5 gallon tank from the loop and abandoned the idea.   

Taso

That was my concern. The smaller quieter compressor would heat up more, and create condensation. Because the short times I ran these compressors, not water in the separators. But I know when I ran this little compressor for 9 hours, It spit out water at the shoebox ( before I had all these water separators )

Than again I'm not concerned about breaking a 25$ compressor, running it too long.

[Taso1000]

Hi All,

Today I was researching activated alumina desiccant for another member who it trying to dry a Yong Heng compressor output.  I was also interested on how it would handle oil contamination.

So after more reading it looks like if activated alumina gets contaminated with oil it stops absorbing moisture. 

Molecular sieve will also absorb oil and become ineffective at absorbing water.  This was a bummer.

Here is an excerpt from response #6 on this web page:

https://www.scubaboard.com/community/threads/13x-molecular-sieve-storage-life.320918/

However here&#8217;s the kicker. I would only recommend this regeneration of molecular sieve process when using oil-free or oil-less compressors.
The reason is quite straightforward. Oil free and oil-less compressors only produce pure distilled water nothing else during the compression process. So the chemical is not contaminated.

Oil lubricated compressor including the Bauer Mariner 3 stage produce imulsified oil and water and your unit uses splash lubrication on the lower stages but oil vapour on the upper. It is this oil vapour &#8220;carry over&#8221; that degrades the molecular sieve rendering is pretty useless for regeneration.

The oil vapour in essence &#8220;coats&#8221; the external surface of each of the molecular sieve spheres with a thin oil film, this effectively blocks that bit of the filter matrix so the dirty wet gas has to find a clean "ball" of chemical to first strip the oil film out of the gas stream before the next clean chemical in the flow chain can get to work on stripping the water vapour.

By regenerating the chemical you fail to remove the oil film and in effect &#8220;cook&#8221; it to the chemical matrix. When you replace the chemical back in the filter tower on the next fill this &#8220;bond&#8221; is broken due to pressure and vapour pressure and all this oil &^^& re enters back into the gas stream. In effect a double dose of trouble for the secondary filter tower to deal with. Iain Middlebrook

I always thought that oils would build up in molecular sieve and could not be removed by heat regeneration.  I hoped I was wrong. 

But today's confirmation that the oil builds up and cannot be removed was disappointing.


So, if you have any oil in your system, pretty much all the desiccants discussed are one use only and not renewable. 

The Shoebox is either using lithium grease, silicone oil or I had considered krytox/ultimox.  I don't know if that will make a difference but I highly doubt it.

Oh well.

Taso

[FuzzyGrub]

FWIW: I'm not seeing oil reach my "little gold" filter, which has cotton before some zeolite.  It is only 3" away from output of the SB.  I do have an aftermarket bleed between the output and this filter. 

[hyperfluous]

The replaceable filters for bauer and what not have the ac after the ms.  Oily vapor doesnt seem to be catastrophic but more so a reason to replace instead of  regenerate the media.

[Nvreloader]

Guys,
Some more info, that may help,

I thought, I would give an update of my F-10 SB/supply air compressor set up, the way I have this set up is,
main air compressor set at 150 psi output, thru 100' of air line, to 3- Wilkerson F-16-04 air filters, (got 6 total for $40).
 
I modified 2 of these filters via getting a fitting that fits the output hole, in this brass fitting I Drilled and tapped a 1/8" push on hose fitting,
then a section of the correct size of clear hosing was pushed on and a compressed fuel line filter was fitted into the end of the hose,
this hose length is long enough to reach/fit to the bottom of each of the bowls.

This makes the compressed air (from supply compressor) travel towards the bottom going thru more filter material,
before going to the next filter for the same process in the last filters.

In the first 2 filters, I am running the Blue 1-2 mm dissecant and the last ones is using a 50/50 mix of 13x -1/2 mm beads and Blue beads,
with the Wilkerson .5 filter out to the SB F-10 compressor.

I just checked these filters, the 1st filter has about a 1/4" layer of top Blue beads that have changed to a lighter color,
(I am color blind, so I can't see what color it is, will have to confirm with the better half),
there is no change in the second filter or the last one that is a 50/50 mix.

I have just filled 2- 4500 CF 45 min tanks to 3000 psi, each was approx 8 hrs of fill time, with a 1/2 hr cool down time each 4 hr run time etc.

I have stood up each tank on the valve end after compressing air, let these tanks set over night and check for any water moisture etc,
I have remove the tank valves and cut off the water trap pipe, milled off a few thousands above the valve end and beveled the ends.

So far there has NOT been any moisture seen or felt, so IMHO, I have a good set up for removing moisture when compressing.
I do disconnect the QD fitting and connect them together to seal the filters etc, when not using the SB.

The only area of concern for me is, that when I drain the  compressor thru the SB during a couple minute fan running cool down,
is I am getting a greyish colored oil residue from the SB output, which I believe to be the Silicone oil from the automatic oilers of the F-10.

I sure hope, I am not getting this silicone oil into my main supply 4500 air tanks, as I don't need any more Kabooms.

Any thoughts, suggestions, good or bad?

Tia,
Don
 

[AlanMcD]

Don,

I think it is all good.  Here are a few specifics though:
1) No worries about "kabooms", even if oil is getting through.  Silicone oil won't combust in that environment, let alone explode . . .
2) I too get a little oil on venting.  Can't be helped as it is a product of lubrication - some gets through.  If you think too much is coming out in each venting event, simply vent more often to reduce the accumulation (since venting blows it out before it can get anywhere).  And keep venting from the Shoebox.
2) I think your air is plenty dry, but to be a bit technical about it, testing to 3000 psi is not going to tell you for sure that you have no water vapor condensing in the tank - air at 4500 psi holds less water vapor than air at 3000 psi, so it could condense out at the higher pressure (if it was there to that, and I doubt it is there with the filter set up you describe).  That said, one fill won't tell you much - if your filters are doing the minimum that they are rated for the most water you would get from one fill would be a few drops, which you probably would not even find as it would likely be spread out over the full surface of the inside of the tank. I checked by removing the valve and visually inspecting and swabbing the inside of the tank after filling a total of about 350 cubic air through the tank and found nothing  (and I am just using silica gel - 1.5 pounds of it in the big filter - and no molecular sieve).

So I think you  are doing great.  And I love the deal on the filters! Just dry out the first one often and all will be great!

[Taso1000]

Hi Don,

I finally found the thread on the black silicone oil coming out of a Shoebox I was looking for.

https://www.gatewaytoairguns.org/GTA/index.php?topic=130000.0

Tom Kay recommended going back to lithium grease to have less lubricant blow by.  I think the black color was oring and guide wear or some interaction with the aluminum parts?  I don't know but I've seen a similar black interaction with mothers aluminum polish on aluminum.  Maybe the silicone the op was using had some additive that reacted with the aluminum or surface aluminum oxide? 

On my next rebuild I think I'm going to remove the silicone oilers and go with ultimox. 

For now I have been adding krytox oil to my wicks every time I run the Shoebox.

I'm gonna top off a 30 minute cylinder to 4500 psi tonight.  I'll keep an eye on my moisture indicator disk "...because it's the only way to be sure."   

Taso

[Taso1000]

I topped off the 30 minute cylinder last night.  The moisture indicator disk after the 3600 psi pmv and before the Alpha filter registered 20% relative humidity. 

Pink indicates the moisture level and blue is the unaffected level. 

https://www.augustindustries.com/moisture-indicator-disk-kit-mois.asp?bc=no

I don't know what that figures out in absolute humidity or parts per million but I think that's pretty good.

I am not positive but I think I the humidity is low enough to not really need the Alpha filter.  I admit I have a hard time understanding the humidity amounts.  The indicator disk is the ultimate decider.  So if the experts can confirm my conclusions that would be great.

I've wanted to to better than just removing liquid water as that leaves the air saturated at about 100% humidity.  Things in our everyday life rust without having direct contact with water.  If I recall correctly corrosion stops at about 45% relative humidity.  Obviously lower than that is better but that 45% is the minimum.

Thanks,

Taso

[Taso1000]

Hello All,

Just a small update.  I replaced the indicator disks with the lower resolution range "10, 20 and 30%" ones from August Industries about 3 months ago.

https://www.augustindustries.com/product/moisture-indicator-disk-2/

I have charged up 3 x 30 minute scba tanks and the new disks, one before the Alpha filter and one directly after it, are registering 10% relative humidity.  I have attached pictures of both indicators. Lavender indicates humidity.

So, I guess my journey is done.  I don't know any other ways to remove more moisture and then how to show measurable results cheaply.  I think I ended up with a very good, low maintenance, moisture removal system.

I learned a lot with my trials and errors.  I think I documented my journey pretty well and I hope the information will be useful to All.  If you have any questions, please feel free to contact me.

Thank you for your patience because this took a lot longer to complete due to my car accident on 03/2017.

Taso