Under slab air drier...

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Working on compressed air plumbing for my home shop and have a question about the best way to hook up what will hopefully be a low cost air drier. I ran about 40ft of 1in galvanized pipe through the sand under my slab (before we poured!). My plan was to run the air through to cool it down and hopefully lower the moisture level. So, any chance this is going to work? If so, should I plumb it before or after the receiver tank? Thanks!
Reply:When you cool the air discharged from the compressor, the water vapor condenses and precipitates out.  The result is liquid water collecting in whatever vessel the air cooled inside of.In order for your scheme to be an effective air dryer, you gotta have some way of expelling the collected condensation from your plumbing or else it will simply build up and move right along through the rest of your system and into your tools and such.Cooling the air does not make the water disappear.  So, what is your plan for getting rid of the water collected in your pipes?
Reply:X2 on what walkerweld said.With no way of removing or anywhere for the water to go that will collect in your buried pipe, I personally believe you wasted 40' of good 1" pipe.MM200 w/Spoolmatic 1Syncrowave 180SDBobcat 225G Plus - LP/NGMUTT Suitcase WirefeederWC-1S/Spoolmatic 1HF-251D-1PakMaster 100XL '68 Red Face Code #6633 projectStar Jet 21-110Save Second Base!
Reply:Originally Posted by duaneb55X2 on what walkerweld said.With no way of removing or anywhere for the water to go that will collect in your buried pipe, I personally believe you wasted 40' of good 1" pipe.
Reply:Not sure if I understand but if it will cool as planned, you need a condensate tank verses a valve.
Reply:Here is a sketch of how I would use the piping set up you described to the best advantage (in my humble opinion).And also I will point out some things you might not have considered to safeguard your plumbing.The air from the compressor tank needs to enter your dryer loop at the highest elevated port.The air entering the condensate collector tank needs to come from the lowest elevated port of the dryer loop.Though I have sketched the condensate collector tank to appear somewhat short (to fit on screen) the ideal collector would be somewhat tall.The air entering the collector needs to come in at a point about half way between the bottom end and top end of collector.This will minimize the chances of turbulence being able to stir up and atomize any condensate that may be standing in the collector tank.The air leaving the collector tank and heading off to your shop tools piping should be run through a "last chance" filter to exclude any solid particles of rust/dirt from getting transported into your tools.If your "compressor room" is subject to freezing temperatures, you will need to also include some type of drain valve at ANY low point in the piping from the compressor tank to the dryer loop and from the dryer loop to the condensate collector.It would be best to configure your piping so that there are no low spots or "traps" anywhere that could fill with condensate which would freeze and burst the piping, but if it can't be avoided, be sure to include a drain valve where necessary.Don't forget that your main compressor tank will still be the primary "air dryer" and you will still need to keep condensate purged from it.I would also include (if it were my project) a "blow down" valve in the piping from the dryer loop before entering the condensate collector tank. Periodically I would open that blow down valve to flush out the dryer loop piping of rust dust and flakes. Because you have used galvanized pipe, there will be some rust formation, but it should not be a major concern (of clogged dryer loop) in your lifetime. Attached Images
Reply:Why not just build an after cooler on your shop wall, with ball valves at the bottom? Attached ImagesDon’t pay any attention to meI’m just a hobbyist!CarlDynasty 300V350-Pro w/pulseSG Spool gun1937 IdealArc-300PowerArc 200ST3 SA-200sVantage 400
Reply:Not sure how cool that set up will be in the hot humid summer time (hot air rises). But that is something I have been thinking about building.OP's under slab idea is a good one especially if on a slope and have room on lower end to drain off condensate.Tim Beeker.
Reply:Originally Posted by tnjindNot sure how cool that set up will be in the hot humid summer time (hot air rises). But that is something I have been thinking about building.
Reply:Thanks for the pic, walkerweld.  That seems like a great setup.  I hadn't thought of the blowdown valve and it seems like a good idea.  I used galvanized (rather than black pipe) because it was going to be underground - not sure if that was the right call.  Having a tank seems like it will greatly reduce the chance of anything making it into the shop piping.  I will be putting some kind of filter on as well, and plan on point of use driers as necessary on any sensitive equipment.  Do you think it would work to use about 4ft of 3-4in dia pipe as my "condensate tank" running horizontally in the compressor room?  Air would enter through the side at one end and leave out the top at the other end.  The low end of the underground pipe run is only about 6in off the ground so if I wanted to use a tank as you've shown it I would have to come back up to enter the tank which doesn't seem ideal.  Maybe not too big of a problem through.  The blowdown valve could still be at the low spot.  Also, is there a reason to put the whole system after the main compressor tank rather than between the pump and tank like CEP suggested?
Reply:I could set it up pretty much exactly the way CEP did, but probably with a blowdown valve after the under slab loop and before it comes back up to the the compressor tank.  Sounds like this system is working well for you.  Thanks for posting.  Can you post a close-up of the filters/driers you have mounted on the wall after the air enters your shop (from the 42deg picture)?  Or just a list of what you used?  Thanks!
Reply:I've since removed them from the wall, and placed them in a frame so I can use them with my nail gun.From left to right in this picture. Motor Guard Model AF-1510, Model CO-4515, Model M-60. Attached ImagesDon’t pay any attention to meI’m just a hobbyist!CarlDynasty 300V350-Pro w/pulseSG Spool gun1937 IdealArc-300PowerArc 200ST3 SA-200sVantage 400
Reply:Originally Posted by duaneb55X2 on what walkerweld said.With no way of removing or anywhere for the water to go that will collect in your buried pipe, I personally believe you wasted 40' of good 1" pipe.
Reply:Almost ran radiant in the slab, but couldn't quite swing it. Climate here isn't too bad and so far I would say that I don't regret it. We did run it in the daylight basement of the house and it's working great there. I'll let you know if running the warm air through the pipes gives me a nice toasty warm stripe down the middle of my shop floor.
Reply:Originally Posted by ccoggThanks for the pic, walkerweld.  That seems like a great setup.  I hadn't thought of the blowdown valve and it seems like a good idea.  I used galvanized (rather than black pipe) because it was going to be underground - not sure if that was the right call.  Having a tank seems like it will greatly reduce the chance of anything making it into the shop piping.  I will be putting some kind of filter on as well, and plan on point of use driers as necessary on any sensitive equipment.  Do you think it would work to use about 4ft of 3-4in dia pipe as my "condensate tank" running horizontally in the compressor room?  Air would enter through the side at one end and leave out the top at the other end.  The low end of the underground pipe run is only about 6in off the ground so if I wanted to use a tank as you've shown it I would have to come back up to enter the tank which doesn't seem ideal.  Maybe not too big of a problem through.  The blowdown valve could still be at the low spot.  Also, is there a reason to put the whole system after the main compressor tank rather than between the pump and tank like CEP suggested?
Reply:I sure hate that you invested in an in slab system before asking first.There are lots of things wrong with the idea of attempting to use an in slab condenser system to remove water from your air compressor supply.-even galvanized pipe will be attacked by the chemicals in the concrete and rust out.-it's almost impossible to design in proper slope and drainage where collected condensate will be separated and blown off in your typical 4-6" thick shop slab.-concrete actually is a decent insulator and transmits heat much slower than air...it is fast to absorb heat at first, but then holds it long after the Delta T is diminished.Best bet is to construct a wall mounted copper piped radiant system like the one in the picture earlier in this thread, BUT one where the pipes are arranged horizontally, NOT vertical....where you compressor discharge goes straight into the radiator at the top, then into your compressor tank from the bottom of the coil......But at the bottom of the radiant coil provide a sizable drip leg and blow off using a auto blow off or one that you operate manually often.
Reply:Actually, the pipes are in the sand under the slab. I think the slope is ok (3in over 20ft on each leg) and the pipes aren't in contact with the concrete. Not sure what the conductivity of the sand is, but I think it is unlikely that I will run the compressor enough to really warm up that much of it. Of course, we'll see.It's actually an older compressor so no warranty issues. Right now I'm tempted to plumb the pipes between the pump and main tank as long as there isn't a check valve (or at least after it). Seems like if I use either hydraulic line or soft copper it should minimize any vibration issues. Also, I'll put in a blowoff valve at the bottom of the lower leg and maybe a small reservoir to catch some water and any junk that gets pushed down the line. Then use the original compressor tank as the last stop before the air heads into the shop. I'll still plan on a point of use filter and drier when I get a plasma and for spraying finish.Gotta finish up a couple other projects first, but I'll let you know how it turns out.
Reply:Originally Posted by ccoggActually, the pipes are in the sand under the slab. I think the slope is ok (3in over 20ft on each leg) and the pipes aren't in contact with the concrete. Not sure what the conductivity of the sand is, but I think it is unlikely that I will run the compressor enough to really warm up that much of it. Of course, we'll see.It's actually an older compressor so no warranty issues. Right now I'm tempted to plumb the pipes between the pump and main tank as long as there isn't a check valve (or at least after it). Seems like if I use either hydraulic line or soft copper it should minimize any vibration issues. Also, I'll put in a blowoff valve at the bottom of the lower leg and maybe a small reservoir to catch some water and any junk that gets pushed down the line. Then use the original compressor tank as the last stop before the air heads into the shop. I'll still plan on a point of use filter and drier when I get a plasma and for spraying finish.Gotta finish up a couple other projects first, but I'll let you know how it turns out.