Water removal recommendations for Shoebox compressor?

[RobertMcC]

Thank you Bill and Alfonso!  It's taken a long time but I am so close to testing the effectiveness of my madness hypothesis lol.   

Alphonso, The way I've integrated the drip leg/trap at the Shoebox outlet, it "should" capture any oil or condensed water that is created due to the pressure maintaining valve.  I hope.  The really low flow should make things easier as it shouldn't be blowing up into the Alpha filter.

Member Humdinger posted a reply, #5, in this thread:  https://www.gatewaytoairguns.org/GTA/index.php?topic=141339.msg1428123#new of a water and oil separator.  If it is nothing more than a chamber to trap oil or water by condensation or gravity then it has nothing additional to offer my setup. 

I am not changing anything in my setup until I compress some are air and have results.  I have the humidity indicator disk right before the alpha and the silica gel right after the membrane dryer. 

Thanks,

Taso

I can tell you up here, 1 water separator and a desiccant filter isn't enough. Because of the well and sump that it is 70 + humidity down in the basement. I got a 5 micron water separator coming. Plus I made a 12x2" larger desiccant filter.

Running the compressor for hours, yielded alot of water and separator didn't trap most of it. I started to run a dehumidifier down there.

I thought about extended the air intake for the compressor. To the duct leading to the register in the dryer above room.

And waiting on a high pressure filter for the shoebox.

[Taso1000]

Robert,

The membrane drier I have should remove the bulk of the moisture down to a dew point of -20° Celsius.  The main reason I installed the desiccant filter is because I wanted to use it as an moisture indicator. 

I also have a moisture indicator between the Shoebox and the Alpha filter.  I haven't installed the indicating disk yet.

Thanks,

Taso

[Trigger_Finger]

A dehumidifier in a closed room running non stop several hrs before pumping hpa sounds like a good idea.

[RobertMcC]

A dehumidifier in a closed room running non stop several hrs before pumping hpa sounds like a good idea.

It can only do so much being that the well is there.

[AlanMcD]

If you are trying to reduce the amount of water vapor in the air that enters your Shoebox compressor, the best thing you can do (other than using an appropriate sized desiccant dryer on the inlet) is to get the air going into your Shoebox as cool as possible.  The easiest way to do that is with a long hose from the shop compressor to the Shoebox to give the compressed air time to cool down to room temperature.  Another good way would be to get a small refrigerator or freezer and run that air hose through it.

The bottom line is that the air coming out of a shop compressor and going into a Shoebox is almost guaranteed to be at 100% humidty level for the pressure and temperature of that air (unless you pass it through a dryer first). All that a dehumidifier will do is reduce the amount of water that condenses out in the shop compressor - it will have no actual impact on the water vapor level going into the Shoebox.

I made this post to help people understand how this all works, and included a PDF with some sample data: https://www.gatewaytoairguns.org/GTA/index.php?topic=139845.0

[Taso1000]

I successfully filled one of my 30 minute scba tanks yesterday!  Finally!  I swapped out the leaking particle filter with a temporary filter as I didn't want the air hose stressing the plastic desiccant filter fittings.

Picture 1 shows the temporary setup.  So it took quite some time to fill the cylinder.  What I did first was let the Shoebox fill all the connections up to the scba cylinder to 4500 psi with the cylinder valve closed.  First to see if the compressor would do make 4500 psi as it's the first time I've run the compressor since I bought it used.  Secondly I wanted to look for leaks.  I didn't hear anything but next time I'm gonna hit all the connections with soapy water to verify. 

The pmv let pressure through the system between 1700 and 1800 psi.  I then monitored the fill time for one hour.  I started timing at about 2840 psi and after an hour was at about 3325 as noted in pictures 2 and 3.  I don't know how that compares to other Shoebox setups.  Picture 4 is of the moisture detector between the output of the Shoebox and the Alpha filter.  The sections should turn lavender when activated.  Since neither section activated I guess I'm below 20%?  I'm not sure.

The next pictures are when the Shoebox automatically stopped at the preset pressure of approximately 4500 psi.  Picture 5 is the gauge on the fill adapter.  Picture 6 is the gauge right off the Shoebox output.  Picture 7 is the cylinder gauge.  Picture 8 is the final reading of the moisture indicating disk.  The 20% section is lavender and the 40% section is slightly lavender on the leading edge.  If someone can tell me more about the indicator disk I would appreciate it. 

Picture 10 is the cylinder pressure this morning after about 12 hours.  The pressure reading decreased slightly so I guess the Shoebox is warming the air a bit.  I don't know if this is better or worse than other compressors.  I kept the input pressure to the Shoebox around 85 - 90 psi as to not generate too much heat in the Shoebox second and third stage. 

I did notice the CAT compressor heads were hand touchable hot.  I think I've seen models with fans on the heads of the cylinders.  I can see if I can retrofit come if it will be of benefit.

So last but not least, I didn't see any moisture come out of the membrane drier purge or from the bleed at my Shoebox water trap.  I also didn't see any water out of the California Air Tools compressor but I did notice colder air come out so I think it had moisture but no liquid water.  The silica gel in the canister seemed to be the same color as when I started.  The input side showed a little pink but it's been like that since I received it.  I guess I should regenerate it to start from vivid blue to be sure. 

I'm sure I forgot something so I will add it as I remember.  Please leave comments with suggestions or questions. 

Thanks you everyone for your patience and help!

Taso

[Taso1000]

I knew I forgot something!     The setup ran in my finished basement and the humidity in the house is between 30 and 36% according to the humidifiers digital humidistat, shows 30%, and separate sensor upstairs that show 36%.  They've never agreed so I don't know which one is correct.

Thanks,

Taso

[RobertMcC]

I knew I forgot something!     The setup ran in my finished basement and the humidity in the house is between 30 and 36% according to the humidifiers digital humidistat, shows 30%, and separate sensor upstairs that show 36%.  They've never agreed so I don't know which one is correct.

Thanks,

Taso

is 6% that much of a difference? I don't think it would be anything to worry about.

[Taso1000]

Robert,

I didn't think so either.  I only wanted to give both readings for reference and let the reader decide.   

Thank you,

Taso

[AlanMcD]

Looking good!  At that low a humidity level, you won't get a lot of condensation in the shop compressor, but the humidity going into the filter system prior to the Shoebox will still be close to 100%.  The driers seem to be doing their job, and it looks like you have no leaks.

It is hard to say for sure, as I have no idea the total volume of the elaborate plumbing system after the Shoebox, but your fill rate is at least 4.7 cubic feet per hour, and probably a good bit higher than that due to all the pipes and the Alpha filter.  Here is how I got the 4.7: the tank increased 485 psi in one hour, and 485 psi is 10.8% of the 4500 psi level at which the tank holds 44 cubic feet of air.  10.7% of the 44 is 4.7 cubic feet in the one hour.

The original Shoebox was rated at 4 cf per hour, and most of the units before the Freedom series seem to run around 5 - 5.5 CF per hour due to the upgrades.  So it looks like all is well in the performance of the your unit - after all, you had to increase the air pressure in all that extra space in the pipes and filter by 485 psi too, so your's is probably in the right range.

Congrats!

[Taso1000]

Thank you Alan!  I think I was leaking at the big dial gauge right at the output of the Shoebox.  I remember screwing it in when I forst got the Shoebox but never with a wrench.  So I removed it last night and removed all the teflon tape.  Once all clean I applied some Vibra-Tite 444 with primer and reinstalled the gauge.

I connected my other 30 minute cylinder and followed the same fill procedure.  This time the Shoebox "seemed" to fill the tubing, Alpha filter and microbore hose much faster.  I won't know for sure because I didn't time it.  I guess what I can do is start the 1 hour test that I did yesterday starting at the same pressure again.   Next time.   

Now I have two full 30 minute cylinders and am very happy!

I was wondering if adding a 5 gallon portable air tank to increase the capacity of the CAT compressor would help?  The CAT starts at about 96 psi and stops at 120.  With the 5 gallon tank in the loop and the Shoebox working the CAT compressor ran for 2 minutes and 31 seconds then didn't cycle on again for 9 minutes and 15 seconds.   My goal would be to keep the CAT compressor output air the coolest.  Without the 5 gallon portable tank the compressor turns on more often but for a shorter time.  I guess I could measure the cylinder head temps with ir thermometer for like 5 cycles and see.   Maybe tonight 

Thanks!

Taso

[AlanMcD]

One easy way to insure the air getting into you manifold set up is at ambient temperature would be to just add more hose in the flow path.  The air flow into the Shoebox is so low and slow that having the extra cool down time in the longer hose might make a difference.  But from the pictures of the filter set up you have I would say that the air will be plenty cool going into your Shoebox anyways . . . .

[Taso1000]

Thank you Alan. 

I think that I'm over thinking...again lol.  I did get the compressor with the aluminum tank to dissipate more heat.  But you're right, the flow is so low it shouldn't matter much.

Taso

[FuzzyGrub]

Taso,

Glad to see you have the lab up and running.   

I don't think your CAT is adding heat with the long times between running and all the surface area of your filters and plumbing, before the shoebox.  You will always get some heat.  When you fill your gun from the tank (no active pistons) the gun will feel warm, and the tank will have a slight cooling.  You can set your shut-off slightly higher, such that when it cools will have a full tank. 

[Back_Roads]

 When I upgraded to a CAT compressor I went with the 5 gal. version, previous compressor was about 3 gal. with the 5 gal. on my f-10, the cycle time is close to 15 minutes, that was a suggested cycle rate I read on the Shoe Box site I do believe.

[Taso1000]

Taso,

Glad to see you have the lab up and running.   

I don't think your CAT is adding heat with the long times between running and all the surface area of your filters and plumbing, before the shoebox.  You will always get some heat.  When you fill your gun from the tank (no active pistons) the gun will feel warm, and the tank will have a slight cooling.  You can set your shut-off slightly higher, such that when it cools will have a full tank.

Thank you John!  I am very glad.  I only wish I had found one drip of water lol.  Maybe in the coming months when the humidity goes up outside.  Maybe I should be careful for what I wish for.   

I thought about bumping the shutoff pressure a bit to compensate for the heating of the air.  I'm going to wait and see how things run for a while.

Thank you,

Taso

[Taso1000]

When I upgraded to a CAT compressor I went with the 5 gal. version, previous compressor was about 3 gal. with the 5 gal. on my f-10, the cycle time is close to 15 minutes, that was a suggested cycle rate I read on the Shoe Box site I do believe.

Thank you James!  I'll search for that.

Taso

[rnabholz]

I successfully filled one of my 30 minute scba tanks yesterday!  Finally!  I swapped out the leaking particle filter with a temporary filter as I didn't want the air hose stressing the plastic desiccant filter fittings.

Picture 1 shows the temporary setup.  So it took quite some time to fill the cylinder.  What I did first was let the Shoebox fill all the connections up to the scba cylinder to 4500 psi with the cylinder valve closed.  First to see if the compressor would do make 4500 psi as it's the first time I've run the compressor since I bought it used.  Secondly I wanted to look for leaks.  I didn't hear anything but next time I'm gonna hit all the connections with soapy water to verify. 

The pmv let pressure through the system between 1700 and 1800 psi.  I then monitored the fill time for one hour.  I started timing at about 2840 psi and after an hour was at about 3325 as noted in pictures 2 and 3.  I don't know how that compares to other Shoebox setups.  Picture 4 is of the moisture detector between the output of the Shoebox and the Alpha filter.  The sections should turn lavender when activated.  Since neither section activated I guess I'm below 20%?  I'm not sure.

The next pictures are when the Shoebox automatically stopped at the preset pressure of approximately 4500 psi.  Picture 5 is the gauge on the fill adapter.  Picture 6 is the gauge right off the Shoebox output.  Picture 7 is the cylinder gauge.  Picture 8 is the final reading of the moisture indicating disk.  The 20% section is lavender and the 40% section is slightly lavender on the leading edge.  If someone can tell me more about the indicator disk I would appreciate it. 

Picture 10 is the cylinder pressure this morning after about 12 hours.  The pressure reading decreased slightly so I guess the Shoebox is warming the air a bit.  I don't know if this is better or worse than other compressors.  I kept the input pressure to the Shoebox around 85 - 90 psi as to not generate too much heat in the Shoebox second and third stage. 

I did notice the CAT compressor heads were hand touchable hot.  I think I've seen models with fans on the heads of the cylinders.  I can see if I can retrofit come if it will be of benefit.

So last but not least, I didn't see any moisture come out of the membrane drier purge or from the bleed at my Shoebox water trap.  I also didn't see any water out of the California Air Tools compressor but I did notice colder air come out so I think it had moisture but no liquid water.  The silica gel in the canister seemed to be the same color as when I started.  The input side showed a little pink but it's been like that since I received it.  I guess I should regenerate it to start from vivid blue to be sure. 

I'm sure I forgot something so I will add it as I remember.  Please leave comments with suggestions or questions. 

Thanks you everyone for your patience and help!

Taso

Hey Taso,

Congratulations on the first run, I know you have been working on your system for a long time.  Nice to see it come together and work for you.

I think you know that my system shares a couple of components of yours, Shoebox Max and a California Air Tools 5 gallon compressor.  I use a MotorGuard M30 filter on the low side and a Gold Filter with molecular sieve on the high side.  I believe it is very effective based on the results I have seen.

The numbers you discuss on your systems performance sound pretty normal to me.  I recently filled a 44cf tank from 0 to 4500 and the run time was almost exactly 8 hours. So it was making around 560PSI into the bottle per hour.  My CAT Compressor cycles on about every 17 minutes or so, and runs for about a minute, so a very light duty cycle.

All of the details on my system's performance are visible here, in my compressor log - https://docs.google.com/spreadsheets/d/1oygaCsqJRjNGGTpXGPIYnAU1ZkyqWbBh5Tz7ODzHb24/edit?usp=sharing

Keeping a log is very helpful in identifying any change in performance and tracking maintenance, well worth the time.

Regarding heat from the CAT - I am sure there is some, but as has been mentioned, the 5 Gallon tank size helps, as does the relatively light volume of the air the Shoebox demands.  As was also mentioned, lengthening the length of the hose between the CAT and the Shoebox is cheap and effective.  I have 75ft of coiled plastic hose between the CAT and the Shoebox, the coils make it manageable and it was about $15 at Harbor Freight.

I smiled when I read your concern over the "loss" of 100 PSI after cooling and making adjustments for it.  That is "Compressor-less" thinking ;^).  It is worth worrying about when you have to go to the shop for refills and pay for every PSI, but remember you are now Master of your Air Pressure Domain -  you can top off anytime, so don't sweat the small stuff.

Regarding leaving the system charged when shut down, I agree with the counsel of not doing so, for the simple reason that "rebuilding" that pressure on the high side does not take that long and does expose everything in the system to unnecessary load or stress.  I found it took my system about 16 minutes to charge the Gold filter and hose to the tank.  I am not in that big of a hurry, and will happily trade that time for extended service between rebuilds and long term health for the Shoebox.

I know that everybody's needs are different and there are lots of options out there for new compressors these days, but I am completely satisfied with my Max set up - slow and steady wins the race.

Congrats on your set up, I know that you have researched and worked hard on it.

Rod

[Taso1000]

Rod,

Thank you!  I'm very glad it's up and running finally.  I think I have the second to smallest CAT compressor.  I picked it for exclusive Shoebox duty.  I almost picked the tiny airbrush version they have but it looked like a toy.     The one I have is the 1/2 horsepower, 2 gallon version.  I would like to think it was designed to last as it configured.  I was wondering if adding tank capacity would hurt it mainly by overheating the heads and to a less effect of warming the compressed air produced more.  I'm pretty sure my air warming concerns are unwarranted as I've been assured my surface are will provide enough cooling.  In my initial planning I had even bought an oil cooler/heat exchanger to cool the compressed air.  I realized it was unnecessary and elected to not use it.   

I was tempted to grab an F10 when their price dropped.  But I was reminded by John, FuzzyGrub, that the F8 and F10 run hotter and are only faster due to the higher low pressure input requirement.  I can't support the 125 psi requirement and I think the added heat created would make the cooled hpa cylinder pressure drop greater.  Plus I am not in a hurry so any speed advantage would have been lost on me.

This was all a proof of concept to see what works, what doesn't and more importantly what is necessary.  It was my small contribution to the wealth of knowledge the forum contains.  There is more detail and thought process than necessary for the readers that will use this thread as reference, I hope.  Brainstorming works best for me so that's why I documented my thoughts too. 

So, to not leave any loose ends, I did hit all the fittings with soapy water from a spray bottle and didn't get any bubbles.  I will take everyone's suggestion to vent the system and not try to save time by leaving it pressurized.  I have some caps to keep moisture and spiders out of the male foster output fitting.

I think I'm going to leave the moisture indicator where it's at for now.  At least till the high humidity months to document what the membrane drier is accomplishing.  I think I'm gonna go ahead and regenerate the silica gel so that I'm not guessing if it's changing color or not. 

Next steps: I'd like to figure out a rebuildable cartridge for the Alpha filter.  I have some sealed indicating 4a molecular sieve waiting to be put into use.  I saw a stainless steel rebuildable cartridge on ebay but I'd like to be able to see if the sieve is indicating moisture.  The current cartridge looks like the endcaps are glued to the clear body.  I may be able to reuse the endcaps but the clear body tube will get trashed on disassembly.  I think.   

Thank you everyone and please keep the discussion and new ideas coming!   

Taso

[Taso1000]

I almost forgot!  I need to put prices on what everything cost.  This is the scary part no one likes to mention.  The hidden costs.   

The upgraded Shoebox Max, the desiccant canister, 4 big sealed desiccant bags of silica gel and drierite, accessories, rebuild parts, one coiled hose and some small capacity Campbell Hausfeld filter group, that I didn't use, for $600 including shipping.

I got the membrane drier for $80.  The CAT compressor was $169.  All the filters, regulators and brackets were $452.  The brass fittings and yellow hoses were $83.  I didn't use all the brass fittings and I skipped the oil cooler so I didn't use it's associated fittings. 

The Alpha filter was $200.  The hpa fittings and moisture indicator were around $120. 

So the grand total is $1704 if my math is right. 

I could eliminate the first regulator, two filters following and the next regulator and save about $200 but may have to change the remaining micro filter cartridge more often.  I could have used my loud, old Craftsman 4.5 horsepower compressor and saved another $169.  If I find the canister filter isn't doing anything I can sell that off for about $50 and not need the last $100 particle filter.  I could probably sell the Campbell Hausfeld filters and hose for $30 - $40.

So the bare bones setup would have cost me around $549 less for a rough total of $1155.

That's around the cost of what a new F10 was selling for a couple months ago without shipping and it still needed water removal. 

A Carette compressor with the Alpha filter is $1699 plus shipping plus a surcharge if you use a credit card, so I have heard, from the exclusive U.S. seller. 

The Altaros is about $739 now.  It needs a huge compressor and water removal.

The $300 Yong Heng compressors are definitely cheaper but they need water removal as they have no water removal.  But they're not even in the running as they cannot top off a scba cylinder to 4500 psi without destroying themselves. 

I don't know anything about the Omega compressors. 

So I am hoping we can compare and contrast the current solutions in price and performance.  My setup is not fast but that was never a priority with me.  I solved that by getting two 30 minute scba tanks that cost me less than $200.  I can shoot off one while the other tops off. 

I was trying for a budget setup with efficient and cheap water removal.  The membrane drier will last for 10 years of continuous use as long as you keep it from getting contaminated with dust and oil.  It doesn't need to be regenerated and it doesn't need electricity.  And it only cost me $80.     But to be honest I did wait for a good deal on it on ebay the same way I got one filter and one regulator used to save money.

Compressing air is not cheap.  lol

Thanks,

Taso