Custom built air dryer for compressed air
Close
Login to Your Account
Page 1 of 5 123 ... LastLast
Results 1 to 20 of 87
  1. #1
    Join Date
    Mar 2009
    Country
    UNITED STATES
    State/Province
    California
    Posts
    4,886
    Post Thanks / Like
    Likes (Given)
    89
    Likes (Received)
    901

    Default Custom built air dryer for compressed air

    I saw a video today about a man who built a dryer out of a 4 inch square box iron 3 feet long.
    Standing the box piece on end a 1 inch pipe ran down the middle with a opening at the bottom.
    Stainless steel wool was loosely packed inside then the ends were welded. A fitting on the top
    of the square box is the input for hot air. The air travels down the box through the steel wool
    and then up through the center tube and out the fitting on the top of the box.The bottom of the
    square tube was drilled and tapped for a manual drain. He made two of these and connected them
    in series.

    I don't care for the iron idea due to rust and scale so it made me think about doing something
    similiar using 3 or 4 incn copper pipe. When I went to the industrial supply store a 20 footer
    of 3 inch copper costs $407. Wow. When I look at some of the crazy pipe arrangements that people
    do I decided to look into a design like this.

    Why I think this is a good idea is that the larger diameter pipe will slow down the air velocity
    and allow better condensation on the stainless steel wool. Any opinions.

  2. #2
    Join Date
    Jul 2006
    Location
    Hillsboro, New Hampshire
    Posts
    7,160
    Post Thanks / Like
    Likes (Given)
    1674
    Likes (Received)
    4919

    Default

    They're ripping you - even McMaster, which is darn high for materials has 3" x 10ft type M for "only" $180:

    5175K142 $180.08 Copper Tubing for Drinking Water, Low Pressure Type M, 3" Tube Size, 3-1/8" OD

    You should be able to find it for under $200 for 20ft, or just get a shorter length from McM. BTW, I made my own air dryer from copper tubing similar to what you described, and it works very well. In combination with a coil of copper tubing in a small fridge, I get very acceptable dry air even in the most humid months.

  3. #3
    Join Date
    Dec 2010
    Location
    WA, USA
    Posts
    1,505
    Post Thanks / Like
    Likes (Given)
    2047
    Likes (Received)
    1039

    Default

    Quote Originally Posted by rons View Post
    I saw a video today about a man who built a dryer out of a 4 inch square box iron 3 feet long.
    Standing the box piece on end a 1 inch pipe ran down the middle with a opening at the bottom.
    Stainless steel wool was loosely packed inside then the ends were welded. A fitting on the top
    of the square box is the input for hot air. The air travels down the box through the steel wool
    and then up through the center tube and out the fitting on the top of the box.The bottom of the
    square tube was drilled and tapped for a manual drain. He made two of these and connected them
    in series.

    I don't care for the iron idea due to rust and scale so it made me think about doing something
    similiar using 3 or 4 incn copper pipe. When I went to the industrial supply store a 20 footer
    of 3 inch copper costs $407. Wow. When I look at some of the crazy pipe arrangements that people
    do I decided to look into a design like this.

    Why I think this is a good idea is that the larger diameter pipe will slow down the air velocity
    and allow better condensation on the stainless steel wool. Any opinions.
    I'm wondering what the function of stainless wool is. Lots of surface area? So what? all that surface just holds precipitate so it takes longer to get to a drain.
    You wrote "4 inch square box iron", not sure what you mean. If cast "iron", lots of thermal mass there. If square steel tube, also not a good thermal conductor. Either way, not good radiators.

    The point is, reducing the temperature of the air is the most efficient way to reduce the moisture content. I guess an iron (or steel) box full of stainless wool could help as long as it is cooler than the input air. For a low volume user it might help somewhat (probably not better than having a secondary receiver [tank]). As air usage increases, the device will just get warmer (less effective at precipitating moisture).

    Using a copper container gets you a better thermal conductor, for sure, but not a very efficient radiator. Twenty 1/4" ID tubes flow more CFM than a 1" ID tube and have almost 7 times the exterior (3/8" OD vs 1 1/8" OD) surface area (= radiator). Better to build an array of small copper tubes than an iron (or copper) box.

  4. #4
    Join Date
    Apr 2013
    Location
    South Australia
    Posts
    418
    Post Thanks / Like
    Likes (Given)
    111
    Likes (Received)
    143

    Default

    Why not use an air con condenser or similar with a fan or mount it in the beer fridge. Out of the way of course

  5. #5
    Join Date
    Jul 2008
    Location
    Sydney, Australia
    Posts
    3,726
    Post Thanks / Like
    Likes (Given)
    2056
    Likes (Received)
    1287

    Default

    Quote Originally Posted by sudsy55 View Post
    Why not use an air con condenser or similar with a fan or mount it in the beer fridge. Out of the way of course
    I tried that, with a few car a/c condensers, and they were very difficult to solder on to. The theory was good but in practice the diameter was small and it just didn't work.

    In the end I got a length of copper tube from the scrappy and ran it between the compressor (where the air is hot and moist) to the receiver. The air cools in the tube and I have a drain at the bottom. It extracts most of the moisture in the air, and I've never felt a need for any further drying. As mentioned, the trick is to handle the water extraction while the air is hot.

  6. #6
    Join Date
    Nov 2005
    Location
    Hudson Valley, NY
    Posts
    966
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    588

    Default

    Go on craigslist.
    Find a junk window air conditioner for free.
    Use the condenser and/or evaporator. There is a built in electric fan that can also be used.

  7. Likes Scottl liked this post
  8. #7
    Join Date
    Dec 2004
    Location
    uk
    Posts
    14,057
    Post Thanks / Like
    Likes (Given)
    4552
    Likes (Received)
    6699

    Default

    You don't want a car ac, there small flow high cooling, you want a intercooler you just gotta find one that can hack the pressure!!!!!

  9. #8
    Join Date
    Mar 2009
    Country
    UNITED STATES
    State/Province
    California
    Posts
    4,886
    Post Thanks / Like
    Likes (Given)
    89
    Likes (Received)
    901

    Default

    A snapshot of the video:

    vlcsnap-2015-10-13-07h20m43s455.jpg

    I would design it so that the it could be disassembled.

    I would like to do something like this. I know I could run a long tube at a decline angle with a drain at the opposite end
    to cool the air. I want something a little more sophisticated.

  10. #9
    Join Date
    Mar 2009
    Country
    UNITED STATES
    State/Province
    California
    Posts
    4,886
    Post Thanks / Like
    Likes (Given)
    89
    Likes (Received)
    901

    Default

    Quote Originally Posted by extropic View Post
    I'm wondering what the function of stainless wool is. Lots of surface area? So what? all that surface just holds precipitate so it takes longer to get to a drain.
    You wrote "4 inch square box iron", not sure what you mean. If cast "iron", lots of thermal mass there. If square steel tube, also not a good thermal conductor. Either way, not good radiators.

    The point is, reducing the temperature of the air is the most efficient way to reduce the moisture content. I guess an iron (or steel) box full of stainless wool could help as long as it is cooler than the input air. For a low volume user it might help somewhat (probably not better than having a secondary receiver [tank]). As air usage increases, the device will just get warmer (less effective at precipitating moisture).

    Using a copper container gets you a better thermal conductor, for sure, but not a very efficient radiator. Twenty 1/4" ID tubes flow more CFM than a 1" ID tube and have almost 7 times the exterior (3/8" OD vs 1 1/8" OD) surface area (= radiator). Better to build an array of small copper tubes than an iron (or copper) box.
    Lots of surface area yes. A larger diameter pipe to slow down the air velocity. Longer contact time for cooling.

  11. #10
    Join Date
    Jul 2012
    Country
    UNITED STATES
    State/Province
    Washington
    Posts
    2,737
    Post Thanks / Like
    Likes (Given)
    1042
    Likes (Received)
    1076

    Default

    Here is a photo of mine, minus the fan I mount in front of it blowing on the compressor. This works fine when it is below 70 degrees out. I have since added 60' of 1/2" id copper tube coiled in a tub of water, $80 with shipping. When it is 110 outside the water is below 80 at the end of the day. Water cooling is way more effective than air. Compressor runs at a 65% duty cycle on one mill and I don't have any water in the air. Yeah it's hokey but it works, it's cheap, and it's low maintenance. One other thing, the birds and hornets love the constant source of water in the summer.


    compressor.jpg

  12. Likes Scottl, Bobw liked this post
  13. #11
    Join Date
    Nov 2009
    Country
    UNITED STATES
    State/Province
    Texas
    Posts
    1,110
    Post Thanks / Like
    Likes (Given)
    73
    Likes (Received)
    311

    Default

    Quote Originally Posted by rons View Post
    .
    Amazon.com: B&M 70298 Hi-Tek SuperCooler Oil Cooler with Fan: Automotive
    I have used these to knock the heat down before our receiver, but if you want dry air you need to go with something like this:

    You could build your own with a freezer full of ethylene glycol and an air to water heat exchanger.
    Ingersoll Rand High-Efficiency Cycling Dryers

    You can not get enough moisture out with just an after cooler.

  14. #12
    Join Date
    Jul 2012
    Country
    UNITED STATES
    State/Province
    Washington
    Posts
    2,737
    Post Thanks / Like
    Likes (Given)
    1042
    Likes (Received)
    1076

    Default

    All of the water traps in my shop are always bone dry. It does help a lot if you catch the water before it reaches your receiver tank, which I now do.

  15. #13
    Join Date
    Mar 2009
    Country
    UNITED STATES
    State/Province
    California
    Posts
    4,886
    Post Thanks / Like
    Likes (Given)
    89
    Likes (Received)
    901

    Default

    Quote Originally Posted by DavidScott View Post
    Here is a photo of mine, minus the fan I mount in front of it blowing on the compressor.


    compressor.jpg
    There is no way to drain residual moisture. This leads to mold. I looked into using a coil but in the vertical configuration.

    index.jpg

  16. Likes bridgedog, Bobw liked this post
  17. #14
    Join Date
    Jul 2008
    Location
    Sydney, Australia
    Posts
    3,726
    Post Thanks / Like
    Likes (Given)
    2056
    Likes (Received)
    1287

    Default

    Quote Originally Posted by rons View Post
    There is no way to drain residual moisture. This leads to mold. I looked into using a coil but in the vertical configuration.

    index.jpg
    That could well be a cut and paste of what I have (albeit a somewhat neater coil). I have the hot air at the top and coils angled such that the water flows with the air. There is a trap at the bottom that auto-drains when the pressure is released at the end of each cycle when the pump unloads. Under the trap outlet I have an ice-cream container to capture the oil and water ejected. The system looks bodgy, but is very effective and I've never seen any water past the receiver. If super dry air was required it would be a good basis to remove the bulk of the water before subsequent processing.

  18. #15
    Join Date
    Mar 2009
    Country
    UNITED STATES
    State/Province
    California
    Posts
    4,886
    Post Thanks / Like
    Likes (Given)
    89
    Likes (Received)
    901

    Default

    Quote Originally Posted by Milland View Post
    They're ripping you - even McMaster, which is darn high for materials has 3" x 10ft type M for "only" $180:

    5175K142 $180.08 Copper Tubing for Drinking Water, Low Pressure Type M, 3" Tube Size, 3-1/8" OD

    You should be able to find it for under $200 for 20ft, or just get a shorter length from McM. BTW, I made my own air dryer from copper tubing similar to what you described, and it works very well. In combination with a coil of copper tubing in a small fridge, I get very acceptable dry air even in the most humid months.
    Copper tubing is cheaper than copper pipe. I think the quote I got was for type K. Type M is tubing.

  19. #16
    Join Date
    Dec 2010
    Location
    WA, USA
    Posts
    1,505
    Post Thanks / Like
    Likes (Given)
    2047
    Likes (Received)
    1039

    Default

    rons seems to be set in his ways, but so that other readers are not mislead; https://sizes.com/materials/pipeCopper.htm

  20. #17
    Join Date
    Jul 2006
    Location
    Hillsboro, New Hampshire
    Posts
    7,160
    Post Thanks / Like
    Likes (Given)
    1674
    Likes (Received)
    4919

    Default

    Quote Originally Posted by rons View Post
    Copper tubing is cheaper than copper pipe. I think the quote I got was for type K. Type M is tubing.
    I went with M as it still has plenty of pressure capacity (~430psi), my outlet pressure is 95psi, didn't see a need to go with K. It's been years and the system still works very well. It is ugly though, hence my reluctance to post pics...

  21. #18
    Join Date
    Dec 2003
    Location
    poulsbo, wa, usa
    Posts
    699
    Post Thanks / Like
    Likes (Given)
    30
    Likes (Received)
    286

    Default

    I have been down the long copper pipe road and gave up and spent a little on a harbor freight cooler ,,, it ran me like $300 with free shipping and it works GREAT.
    1/2" NPT in and out and just plug it into a 110V outlet and be done .... Normally I`m the first one to say harbor freight sells only junk but they screwed up and built a good air dryer for once.

  22. Likes snocat_trf, Philabuster liked this post
  23. #19
    Join Date
    Mar 2009
    Country
    UNITED STATES
    State/Province
    California
    Posts
    4,886
    Post Thanks / Like
    Likes (Given)
    89
    Likes (Received)
    901

    Default

    Quote Originally Posted by extropic View Post
    rons seems to be set in his ways, but so that other readers are not mislead; https://sizes.com/materials/pipeCopper.htm
    Maybe I got the type wrong because I don't remember the actual quote. What I do know is the stuff I was looking at was pipe that could be
    buried in the ground, not the stuff that you connect to the back of a refrigerator for a ice maker.

  24. #20
    Join Date
    Jul 2012
    Country
    UNITED STATES
    State/Province
    Washington
    Posts
    2,737
    Post Thanks / Like
    Likes (Given)
    1042
    Likes (Received)
    1076

    Default

    rons, if I have mold in my tubing what must my receiver tank look like? It's been 2 winters without mishap. I don't think there is enough residual moisture to worry about.


Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •