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Thread: Air compressor - Cooling the air

  1. #26
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    Re: Air compressor - Cooling the air

    DaveC & Tweake: Our freezers go to -10 which is where we have them set. Once I add ambient temp water or even chilled water to get a working liquid I'm up above 0. A few minutes of actual use and my guess is I'd be lucky to see any ice at all, just cold water getting warmer by the second.

    I don't see how attempting to go below freezing could possibly work. The condensed water would form an ice dam inside the plumbing rendering the system useless.

    The last painting I did was at 95 degrees ambient, parts in full sun probably at 140-150, compressor running non stop and I noticed the primer I was applying looked wrinkled or lumpy. I felt the compressor tank and it was really hot. I think the air temp going through the gun was affecting the primer. The sun preheating the steel had never before had a similar effect so I think it was the combination of sun preheat and hot gun air. I just got a huge heavy duty tarp via Amazon to rig an umbrella for painting.
    To my knowledge, I own:
    50% of all the plasma cutters,
    33% of all the TIG welders and
    20% of all the MIG welders on the island.

    I own 1 of each.

  2. #27
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    Re: Air compressor - Cooling the air

    Can you run some loops under ground as a "cooler" ? Kinda like a solar water heater turned under sand air cooler thing ? That cooler thing you could just do in a sch 40 snaked pvc. 1 1/4 and a mountain of sweeps, or heat and bend ?
    No worries about the explosion paranoia under the sand. I've worked in hillbilly shops plumed in PVC my whole life, although I used iron pipe in mine.

  3. #28
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    Re: Air compressor - Cooling the air

    Bonzoo: The "dirt" on the island is, what I call, "pre rock". You can swing a pickax and possibly dent the ground. The holes I recently dug to anchor the gate posts for the fence were hand dug because I don't have an auger and can't rent one; there aren't any. I bought a post hole digger and quickly realized it was absolutely useless.
    I then bought the largest lag bolt I could find, cut the hex head off and welded the bolt to a 3' section of iron pipe so that it wasn't perfectly aligned down the pipe center line. At the other end, I welded in a short piece of 1/2" smooth rebar so that I could turn the "tool" in a large drill. This is my auger. Because the lag bolt is purposely slightly eccentric, it twists and turns its way past all the rocks and manages to disturb the ground enough for me to use a very narrow spade to remove some dirt. Lather, rinse, repeat. 4 holes took 2 days to complete to 27" depth.
    Digging is not something I want to do any more of than absolutely necessary.
    To my knowledge, I own:
    50% of all the plasma cutters,
    33% of all the TIG welders and
    20% of all the MIG welders on the island.

    I own 1 of each.

  4. #29
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    Re: Air compressor - Cooling the air

    Let me TRY to make this understandable.

    The Reference points used as measurements of "dry air" such as -10 and -40 are little different than the and on a measuring cup.

    -10 and -40 are merely indicators of the Dew Point of the airstream leaving the "dryer".
    Those measurements are also only true and relevant when the drying mechanism is working optimally.

    If the airstream leaving the system is in excess of machine capability the compressed air will be way wetter than the numbers indicate.

    Drying compressed air isn't necessarily difficult, but a hell of a lot of money is made by ???? sales of unnecessary equipment.

  5. #30
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    Re: Air compressor - Cooling the air

    Quote Originally Posted by RoatanBill View Post
    DaveC & Tweake: Our freezers go to -10 which is where we have them set. Once I add ambient temp water or even chilled water to get a working liquid I'm up above 0. A few minutes of actual use and my guess is I'd be lucky to see any ice at all, just cold water getting warmer by the second.

    I don't see how attempting to go below freezing could possibly work. The condensed water would form an ice dam inside the plumbing rendering the system useless.

    The last painting I did was at 95 degrees ambient, parts in full sun probably at 140-150, compressor running non stop and I noticed the primer I was applying looked wrinkled or lumpy. I felt the compressor tank and it was really hot. I think the air temp going through the gun was affecting the primer. The sun preheating the steel had never before had a similar effect so I think it was the combination of sun preheat and hot gun air. I just got a huge heavy duty tarp via Amazon to rig an umbrella for painting.
    with a cooling type dryer you can't go lower than about 35F otherwise you risk ice forming inside and blocking the air pipes which is why refrigerated dryers don't go any lower. to go lower than that you need to change methods and use desiccant or membrane systems.
    this is assuming you even need to go lower than that.

    the trouble with a compressor running when your using the air is the air doesn't get cooled in the tank (with most normal tanks) as it goes in and straight out. tanks are poor at cooling and air needs to sit in there for a while for it to cool.
    so i guess the issue with the paint was moisture coming through (i'm not a painter).

  6. #31
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    Re: Air compressor - Cooling the air

    Quote Originally Posted by Virgil5 View Post

    Drying compressed air isn't necessarily difficult, but a hell of a lot of money is made by ???? sales of unnecessary equipment.
    absolutely correct.
    this is why you need to work out what amount of drying you actually need. no point having -40 dew point if 35 is all you need.
    also gear needs to be sized correctly and setup correctly. taking shortcuts may mean you save 20% but you don't actually get the results your paying for.

  7. #32
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    Re: Air compressor - Cooling the air

    Virgil5: If I cool the air to somewhere in the +40 degree range, isolate the condensate and then let the air warm up traveling through a 21g tank sitting at 95 ambient, I'm guessing that the air will be very OK for my plasma cutter and painting gear. I could even run it through a copper coil before it hits that small tank, if testing indicated that to be a good idea.

    Tweake: I hadn't considered water as the source of the mushy primer look, but you make sense.
    To my knowledge, I own:
    50% of all the plasma cutters,
    33% of all the TIG welders and
    20% of all the MIG welders on the island.

    I own 1 of each.

  8. #33
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    Re: Air compressor - Cooling the air

    Quote Originally Posted by RoatanBill View Post
    Bonzoo: The "dirt" on the island is, what I call, "pre rock". You can swing a pickax and possibly dent the ground. The holes I recently dug to anchor the gate posts for the fence were hand dug because I don't have an auger and can't rent one; there aren't any. I bought a post hole digger and quickly realized it was absolutely useless.
    I then bought the largest lag bolt I could find, cut the hex head off and welded the bolt to a 3' section of iron pipe so that it wasn't perfectly aligned down the pipe center line. At the other end, I welded in a short piece of 1/2" smooth rebar so that I could turn the "tool" in a large drill. This is my auger. Because the lag bolt is purposely slightly eccentric, it twists and turns its way past all the rocks and manages to disturb the ground enough for me to use a very narrow spade to remove some dirt. Lather, rinse, repeat. 4 holes took 2 days to complete to 27" depth.
    Digging is not something I want to do any more of than absolutely necessary.
    Haha. Like the FL Keys. Pure oolitic lime stone. It takes a dent backhoe 6 hours to do a septic and drainfield in SFlorida. Terrible digging

  9. #34
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    Re: Air compressor - Cooling the air

    Quote Originally Posted by RoatanBill View Post
    Virgil5: If I cool the air to somewhere in the +40 degree range, isolate the condensate and then let the air warm up traveling through a 21g tank sitting at 95 ambient, I'm guessing that the air will be very OK for my plasma cutter and painting gear. I could even run it through a copper coil before it hits that small tank, if testing indicated that to be a good idea.
    Where you're sitting ought to qualify you to be some kind of Official Tester, but you'll go broke before you can test half of the ideas on the InTurdnet.

    Contrary to popular belief, copper offers damn little unless you're building a coaxial cooling line. How much water you got to flow for air cooling and what temperature is it?

    Copper doesn't give off much heat by radiation, which explains all the aluminum fins pressed onto copper tubes in heat exchangers.

    That established, and minimally 17 PHD candidates will be along to swear I'm wrong,

    Lets look at what's going on with the compressed air stream when it leaves the compressor.
    1, it's hot as hell, often 200 in your location.
    2, it's carrying a small boat load of water entrained in the airstream.
    3, it's traveling at Warp 4.
    In less than 1/10 second that slug of compressed air that was shipped by the piston stroke will get from the compressor to the receiver.

    Believe me, there are maximum temperature exchanges you can get in 1/10 of a second, and it won't matter if you run the slug of air through a foot of pipe or 200 feet of pipe, time is your enemy.

    Oddly, there is a device you can make that functions very well between compressor and receiver and there are infrared images proving it knocks 100 out of the airstream, and causes a lot of liquid water to fall out, and there are at least 1000 posts on the InTurdnet by everybody from an Engineer with a diploma to a sh!t shoveler clearly stating the device can't work. Thing is I know Bumblebees can fly and I know this device works and removes one hell of a lot of water, but I'm too old to argue with brilliant young men.

    So, lets say you stick a coil from an air conditioner between compressor and receiver and drop maybe 10 or even 15 passing thru.
    10% drop in temperature isn't going to drop much water out of the airstream and 120 air is hot enough to resorb most of that water as it leaves the coil because the water didn't have time to drop into a sump which the coil don't have.

    Sop now you're shoveling 120 supersaturated air into the receiver, where it needs TIME to lounge and drop what little water has condensed to liquid. Guess what ain't gonna happen?

    That 2 second old slug of supersaturated air is heading out of the receiver at Warp 1 faster than I typed 5 words due to a lot of reasons including ushers and occupado signs in the vessel.
    Let's be generous though and allow maybe the slug dropped 1% of the water it was carrying as it surfed across the receiver that was plumbed by a clueless person with a tood.

    So, now Slug and all his followers are marching along a pipe looking for the exit ramp to their job.
    Among the things I'll bet a buck on are;
    The pipe ain't installed correctly, but it cost 3 times what it is worth because it came from some InTurdNet seller like Scamazon or Eastwierdos and they sell good sh1t. It's 10 times gooder if it has a blue plastic coating and requires special fittings that will self destruct in 7 years. And it gets Man Cave Points.

    We also know the line ain't coaxial because the concept wasn't taught in Engineering School. Heat exchangers gotta be as restrictive as possible according to some Purrfugger's book.

    It'll also help a lot if the pipe is painted any color but flat black because nobody was awake in class when the thermal radiating & collecting properties of flat black were discussed in class.

    I'll also bet another buck taps leaving the line do so either horizontal or down from the trunk. God himself with Pete and a band of Angels running Rigid pipe lathes can't get a tap to leave an air line in an up direction even though Sprinkler fitters can understand the concept and so can gasfitters. That's a whole different church though.

    Then of course there must be a squishlesing concentrating toiletmatic thing that cost 172 from Snap On favored by lesbians, a toilet paper filter that can't use toilet paper and is really a knockoff of a 1950s bypass oil filter, a regulator and some cheap hose.

    When you plug a blow gun into the hose and puff 2 fartpressure air coming through all those filters, it's cold air.
    DOH, you just discovered refrigeration by expansion. Blow for a while and you got a wet hand and a puddle.
    Charge extra for paint jobs with croutons in the paint, it worked for United Air Lines.

    Ya know what, you could have had a much better system for a hell of a lot less money and not need to steal toilet paper from work to fill your filter cause you're too broke to turn the compressor on.

  10. #35
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    Re: Air compressor - Cooling the air

    Virgil5: I happen to know something about beer brewing where hot wort is rapidly cooled via a counter flow heat exchanger; coaxial tube in tube. The tubes are even specifically dimpled in the best versions to create turbulence in flow of both the hot wort in one direction and the cooling fluid, usually chilled water, in the opposite direction. Obviously there's no attempt to remove anything but heat in this process to be able to add the yeast to start fermentation.
    Those heat exchange are expensive, usually made out of stainless steel because copper has an undesirable reaction with the hot wort. Although that level of tech is known to produce dramatic temperature differentials input to output, I wasn't considering using it because it's overkill for painting and air for a plasma cutter.
    I will probably over engineer a solution because that's my training.
    To my knowledge, I own:
    50% of all the plasma cutters,
    33% of all the TIG welders and
    20% of all the MIG welders on the island.

    I own 1 of each.

  11. #36
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    Re: Air compressor - Cooling the air

    Gee, let me remember back to 1966. Hot wort comes from the giant beer kettle that is made from COPPER with a copper dome over the kettle leading to a heavy walled steel exhaust pipe. Then the wort passes thru a filter where most of the spent grain residue is filtered out on the way to the wort tank where it is cooled by copper coils surrounding the tinned copper liner in the wood tank.

    Then when the fat Brewmaster agrees the wort is cool enough to not kill the yeast the kettle man hoists 2 stainless buckets of yeast up to the deck and pours the yeast gently into the wort tank where it gets to fermenting and growing. At that point the stainless pump pushes the batch to a glass lined tank via a stainless pipe.

    So, please tell me how wort that just left a copper kettle is going to be harmed by contact with copper before marrying up with the yeast.

  12. #37
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    Re: Air compressor - Cooling the air

    Virgil5: That was then. Folks have discovered things in the interim.

    Many home brewers still use copper heat exchangers because they're much less expensive than their stainless versions. Some types of beer are less affected by the copper than others. If you check on the kettle sellers, I doubt you'll find many copper components. Of the ones that interested me, there were no copper parts from any of the manufacturers.

    You might find homebrewtalk.com an interesting web site.
    To my knowledge, I own:
    50% of all the plasma cutters,
    33% of all the TIG welders and
    20% of all the MIG welders on the island.

    I own 1 of each.

  13. #38
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    Re: Air compressor - Cooling the air

    Quote Originally Posted by RoatanBill View Post

    You might find homebrewtalk.com an interesting web site.
    i havn't been on there in ages. home brew came to a stop when i shifted house. still got a couple of carboys to bottle one day.

  14. #39
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    Re: Air compressor - Cooling the air

    Quote Originally Posted by RoatanBill View Post
    Virgil5: That was then. Folks have discovered things in the interim.

    Many home brewers still use copper heat exchangers because they're much less expensive than their stainless versions. Some types of beer are less affected by the copper than others. If you check on the kettle sellers, I doubt you'll find many copper components. Of the ones that interested me, there were no copper parts from any of the manufacturers.

    You might find homebrewtalk.com an interesting web site.
    Home brewing don't count. 1000 gallons is about a correct batch.
    I haven't been back to the brewhouse since the 70s, but the beer foundry was still advertising their copper cookers into this century.

    Hell I only drink beer with Limburger sammiches. I didn't even drink it when it was free and all you want in the beer foundry.
    Best use I found for beer was dumping it by the half barrel on a few guys who were covered with liquid caustic when a line let go. Beer is far superior to water in neutralizing caustic eating flesh off a man's body.
    The spike on a Halligan bar will take the bung out of a barrel in under 2 seconds.

    Maybe you have too much beer in your compressed air stream.

  15. #40
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    Re: Air compressor - Cooling the air

    Someone just posted somewhere where they use a Cooper coil in a plastic 55 gallon drum full of water. That would be a great way that can't fail unless your pushing a 20 HP AC non stop.

    I think it was listed under a air filtration thread.

    Sent from my 2PS64 using Tapatalk

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