Intercooled Air Compressor

[jakeru]

Yeah I am glad I picked up the 120V fan when I saw it. The copper pipe connecting my compressor outlet (behind the black plastic shroud up high) to the unloader valve (on top of tank, and brass) measures 3/8" OD with compression fittings at each end, so one idea to further "intercool" this pipe is to simply replace the short copper tubing with a longer length (could use 3/8" OD soft copper refrigeration tubing), and bend/snake that around inside the shroud perhaps (if there's room) where the cooling air would flow past it.
Attachment 2001
I know that this piece of copper tubing can get plenty hot, because I had some polyethylene tubing laid next to the copper and at one point it got hot enough to melt the PE (which would be ~230F I figure.)

Here is a link to 10 feet of the 3/8" OD soft copper refrigeration tubing for $12.50 from Home Depot:
http://www.homedepot.com/h_d1/N-5yc1...atalogId=10053
(wonder if I should I try upsizing it to 1/2"?)

This pic shows how I routed the wiring for the fan... pretty simple done this way.
Attachment 2000

I blew a head gasket out on this thing by the way, not too long after it was new. I found the original gasket material was not oil resistant, so it got weakened where oil had softened it. I cut a new gasket for it out of oil resistant sheet gasket material and have run a ton of hours on it since then.
Attachment 2002

[Timberwolf]

That looks good. About the exact fan I need haha. I held that small fan I have on the top and it made a huge difference. No moisture in the tank at all. I may just mount this one temporarily and look for a muffin fan like yours.

[Timberwolf]

Well got the fan mounted tonight and wired into the motor so it kicks on with the compressor. Just used some old scrap angle iron I had on hand to fab up the mount. Not clean looking like what I wanted but it works great. No complaints on the functionality

[ogorir]

here's a couple pics of my current setup:

Attachment 2226Attachment 2227Attachment 2225

we've got 2 HF compressors, one's a newer version of jakeru's, the other is an 8 gal 2hp horizontal, both run into 1" black pipe thought the shop. I just re-did the lead-in lines to the 1' pipe with 1/2" hose today, which made a big difference. I took the regulators off both the compressors when I saw this thread the other day, can't believe I didn't think of that earlier, especially because the gauge on the vertical tank was broken anyway.

once one of these things dies for good, we're getting a real compressor, but in the mean time I'd like to come up with a decent cooler/dryer that I can also use with a 80ga vertical 5 or 7hp 2 stage compressor. my inital thought was to take a 50' coil of 1/2" soft copper line, coil it around in a cone shape, and mount a fan blowing up through the cone. that may or may not work better ducted.

the intercooler also looks like a good choice, but I suspect it might choke down a big compressor? (20+cfm)

[yotarover]

will this setup keep most of the water out of the tools. last in line dryer i used it wasn't helping at all and i keep my compressor inside on the back porch where it's mostly dry. i've gotta drain that thing after each use no matter where i plug it in at. i tried the hf water separater/oiler for a while it's like it loves to fill up with water but my air tools work perfectly fine. am i doing something wrong the air filter is clean and stays dry

it's a discontinued 05 Farmhand 240/120v 125psi 30gal 5hp 6.5scfm from tractor supply upright not very noisy. if anybody can help me figure out why it fills up with so much water so fast i'd appreciate it

[Timberwolf]

The water is just part of compressing the air. THe hotter air can hold more moisture. By cooling it we cause that moisture to condense and then since it is heavier it settles to the bottom of your drain. This will not remove 100% of the water but will come pretty close and more than good enough for a home shop setup. Way cheaper than a refrigerated drier.

As for working with machines that produce a lot of CFM's, this will also work but you need to plan accordingly. The IC tubes would need to match the size of your original tubing running from the compressor to the tank.

[parkour]

For the heat exchanger, one could see about getting an old window air conditioner. One unit will have two large heat exchangers with long copper pipes, and is well suitable for the pressure from an air compressor. It would definitely work between the compressor discharge line and the tank, since at that point the mass flow is minimal, but would probably be an unacceptable restriction between the tank and the tool. It is best to put it between the compressor and the tank anyway, since there it will help keep the tank dry also. If you're all kinds of gung-ho, you could probably hack a dehumidifier to function as a heat pump to chill the intercooler.

[everlastsupport]

For the heat exchanger, one could see about getting an old window air conditioner. One unit will have two large heat exchangers with long copper pipes, and is well suitable for the pressure from an air compressor. It would definitely work between the compressor discharge line and the tank, since at that point the mass flow is minimal, but would probably be an unacceptable restriction between the tank and the tool. It is best to put it between the compressor and the tank anyway, since there it will help keep the tank dry also. If you're all kinds of gung-ho, you could probably hack a dehumidifier to function as a heat pump to chill the intercooler.

I know nothing about AC, but any oils in the heat exchangers to worry about? If so, what is a good cleaner?

[parkour]

The times I have seen the inside of sealed air conditioner units, I did not see any oil residue. What I have seen was bright and clean. Automotive AC units, on the other hand, are an oily mess. I would think that the sealed units must not circulate the oil as deliberately as auto ac units do. In any event, I would expect that acetone would do a fine job of removing any oil that may be present.

[Timberwolf]

Acetone would work, but I started with a brand new core for a few reasons. The biggest is the fact that all of the AC units I found had a lot smaller tubes and would cause too much restriction.

I contemplated putting the exchanger in an ice bath but in the end not worth it and was a lot easier to slap a fan on it and call it done. Hundred degree temps and 100% humidity and it's keeping my air dry. I can't complain

[ogorir]

I wonder if using an actual refrigerant loop and a heat exchanger might not be a bad idea. interpolating from these charts, it looks like 3/4" pipe is your minimum for virtually eliminating pressure loss at 20cfm : http://www.engineeringtoolbox.com/co...ss-d_1014.html
you might be able to get away with 1/2", but without having a graph to look at, it's hard to say where the cutoff is. if anyone has the equations for this, I'd like to take a look. I'll see if I can find them later today.

[yotarover]

The water is just part of compressing the air. THe hotter air can hold more moisture. By cooling it we cause that moisture to condense and then since it is heavier it settles to the bottom of your drain. This will not remove 100% of the water but will come pretty close and more than good enough for a home shop setup. Way cheaper than a refrigerated drier.

will it still be safe to use with plasma or will i need to add more driers and filters ? or should i find another compressor and make it dedicated for just that purpose. when i go to change tools you can feel the water or moisture and it's really bad when i use my dart cut off tool it's got front exhaust ports. and i have to wear gloves because that thing gets so cold it's like holding a solid chunk of ice. i've got 100ft hose. this is really starting to bother me but at least this thread helps narrow it down.

[Timberwolf]

The coldness is just from air expanding....not a lot you can do to get by that. Removing moisture is good for all air tools and especially great for the plasma. The drier air helps the consumables last longer. This is a good idea for any compressor. Keeps moisture out of the tank and out of your tools. I've also added another seperator on the output side before the hose to get out any remaining moisture and then a disposable on the plasma cutter itself.

[jakeru]

will it still be safe to use with plasma or will i need to add more driers and filters ?

I would add an air desiccant dryer immediately before your plasma's air inlet. Having it located downstream of any air pressure regulator/filter/water trap seems like the best idea.

Although i don't do a whole lot of plasma cutting, I noticed a dramatic difference in lifespan of my plasma consumables after adding the inline desiccant dryer. They are available for ~$8 from HTP ("Motor Guard" brand, as pictured), and also possibly cheaper on "closeout/clearance" right now from Harbor Freight.

[parkour]

I found a discussion about regenerating desiccant.
http://www.thehighroad.org/archive/i.../t-475508.html

I expect that the plastic would be able to handle 190F or so w/o getting so soft as to deform under its own weight. As I understand it, the indicator dye is a bit of a health hazard, so I would avoid using the food oven.. I like idea of putting it in a perforated metal can in the sun.

[ogorir]

when I asked the paint rep at my dads about reusing the desiccant in the paint booth air, he said a few guys in the big shops had tried baking it, but it only lasts about 10% as long as a new batch of desiccant before it gets saturated again. we decided to forgo the experiment.

[parkour]

Does the rep you spoke with sell desiccant? If the story is true, perhaps they damaged the desiccant by over heating it. Mentioned in the thread I linked to was a comment about baking at too high of a temperature and damaging it rather than just drying it. Too few details are provided to fly in the face of product labeling saying to bake the desiccant to dry it.

[Timberwolf]

People dry this sutff out all the time. Wouldn't do it in the wife's but I don't see why you couldnt get a cheap small toaster oven and dry it out.

[parkour]

My impression was right. I searched and found that the blue/pink indicator dye is cobalt chloride. It is toxic to humans. http://www.google.com/search?q=cobalt+chloride+toxicity

[ogorir]

the rep is a pretty good friend, I trust him pretty thoroughly, but he didn't try it personally, he was just reporting what he'd heard from some of the guys in the big body shops. it wasn't a big enough expense for us to pursue any farther. my dad has gone through 3 desiccant changes in the spray booth air filter over 7 years. at $80/change, that's pretty irrelevant. having a 2-stage pre-filter helps extend the desiccant life a lot, though. he's got this system: http://www.autorefinishdevilbiss.com...on/DAD500.aspx

I'll be buying one when we get our spray booth, I have zero complaints with it. I wouldn't run a whole shop with it, but you could use it for paint or plasma use pretty much indefinitely.

if someone tries drying out the desiccant, I'm interested to know how long it takes to get saturated again.