Removing Air Line Moisture

[Rudy]

I've had my air operated diaphragm pumps "ice" up from time to time on really busy days. After a lot of research, I thought I'd share an Intercooler that I've added to my compressor. Unlike a tank drain, the moisture is removed BEFORE it enters the tank. You see, hot air can hold much more moisture than cool air, therefore the trick is to cool the humid, hot, and moist air thereby causing the water to condense out.

I purchased a racing transmission cooler online for about $100. The hot compressed air enters the cooler at the top and the cooler air exits the bottom. FWIW, I've checked the air going in at 240 degrees F, and it exits at about 4 degrees above ambient.....approximately 75 degrees. A Rotron fan (Used on ebay about $35) pushes air across the heat exchanger. An moisture separating air filter is placed in the exit line between the heat exchanger and the tank. Mine has an automatic "dump" so the whole operation operates "unattended".

It's amazing how much water this setup removes. I've had no problems with "icing" since.

You can view the setup via the following links:
http://img822.imageshack.us/img822/5908/imag0066o.jpg
http://img703.imageshack.us/img703/4759/imag0063o.jpg
http://img831.imageshack.us/img831/7306/imag0062ze.jpg

 

[under pressure]

All I can say is wow, thats a pretty impressive set-up,I like your ingenuity,

 

[Washmee]

The last compressor I bought came with an aftercooler already installed. The pulley on the pump is designed as a cooling fan and pulls air through the aftercooler. Works great.

http://www.grainger.com/Grainger/SPEEDAIRE-Air-Compressor-1WD63?Pid=search

 

[MEP001]

The last compressor I bought came with an aftercooler already installed. The pulley on the pump is designed as a cooling fan and pulls air through the aftercooler. Works great.

That's quite a bit different. His setup cools the air after it's been compressed and then runs it through a water filter so air won't enter the tank. Yours just has cooling fins on the connecting tubes between the two stages so the air entering the second piston is condensed slightly - the air entering the tank isn't cooled or filtered.

 

[Washmee]

That's quite a bit different. His setup cools the air after it's been compressed and then runs it through a water filter so air won't enter the tank. Yours just has cooling fins on the connecting tubes between the two stages so the air entering the second piston is condensed slightly - the air entering the tank isn't cooled or filtered.

No, my compressor has a radiator type aftercooler that is mounted behind the cage over the pulleys. It is plumbed directly before the tank and cools the air enough to allow the water to condense in the bottom of the tank. Pretty much the same way he has plumbed his, except mine uses the the head pulley as a cooling fan. There is an automatic drain valve that opens after each cycle to drain that moisture from the tank. I agree that it does not have a water filter, but it is quite effective in eliminating moisture in my air lines. The picture on the page I linked to is a generic one that does not depict the actual compressor I own.

 

[mjwalsh]

No, my compressor has a radiator type aftercooler that is mounted behind the cage over the pulleys. It is plumbed directly before the tank and cools the air enough to allow the water to condense in the bottom of the tank. Pretty much the same way he has plumbed his, except mine uses the the head pulley as a cooling fan. There is an automatic drain valve that opens after each cycle to drain that moisture from the tank. I agree that it does not have a water filter, but it is quite effective in eliminating moisture in my air lines. The picture on the page I linked to is a generic one that does not depict the actual compressor I own.

Washmee, Rudy, & our friend Mep001 & others,

http://www.grainger.com/Grainger/Air-Cooled-Aftercooler-4UJG3

Using this aftercooler I wonder how tough it would be to do an aftercooler on an Ingersol Rand 2 stage. I notice that the Intercoolers (Rudy's) that I checked out the maximum rated pressures are less than the 150 PSI that I compress to with the 5 HP 2 stage Ingersol Rand. I like the idea of using the big pulley as the fan as there is a lot of air generated from that when it runs. I also like the idea that when the compressor stops running each time it causes the bottom of tank to do a synchronized quick drain of the water just created.

On the other hand, ideally the water is taken out like Rudy's before it even goes into the tank. I wonder how a control could optimally manage the autodrain --- it seems like if open drain action was sychronized for a few seconds after a compressor run event it would be the best.

We blow out our lines often enough during our North Dakota winters so I know the drier the air the better --- even from that perspective!

MJ

 

[Washmee]

Mike, That is the exact aftercooler that is used on my compressor.

 

[MEP001]

The picture on the page I linked to is a generic one that does not depict the actual compressor I own.

Sorry, I only looked at the picture and didn't read the specs in your link.

This unit might be worth looking at:

http://cgi.ebay.com/ebaymotors/REMO...ptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories

 

[Reds]

I bought an I.R. Cycling Refrigerated Air Dryer (D41NC) and it solved my moisture problem. I still have moisture build up in my compressor tank because it is plumbed in after the tank, but out in the bays I get zero water in my filter bowls. Not the cheapest way to go, but certainly efficient

 

[Rudy]

The "cooler" I used is a B&M #70274. It had 1/2" female fittings, which made hookup easy. I bought it online for less than $90. If I remember correctly, it is pressure tested to 200psi and is rated at over 29,000 BTU's.

My initial setup also tried using the pulley fan as the "air" source. Although it worked, it slowed the flow across the compressor which defeats the purpose. I now get even better cooling of the compressor with the addition of the electric fan. My compressor is 3phase, so I robbed 110v from one leg and the neutral to run the fan. When the motor contactor closes, the fan starts. My fan, a Rotron CL2T2 is just the right size and gives good airflow.

Most good compressors have a "pressure relief" which bleeds down the head pressure after the unit turns off. If your air filter doesn't have an auto drain, you could conceivably plumb a line from the bottom of the filter to the pressure relief bleed line (it's the small gauge line that comes out of the pressure switch that turns the compressor on and off). That way, when the compressor turns off, you'd be bleeding the pressure via the bottom of the bowl which would also have the effect of venting collected moisture. The moisture, however, would be exiting very close to electrical connections....so be careful.


I looked at refrigerated air dryers, but they were expensive. They cost money to operate and take up valuable shop space.

The trick in ALL of this is to remove the bulk of the moisture BEFORE the tank. Before I added the aftercooler, the TANK was the cooling medium.....hence that's where the water condensed. The more the compressor ran, the hotter the compressor got, and the hotter the compressed air became. This hot air holds A LOT of moisture. That's why I wouldn't have a problem on a slow day, but why I had problems on very busy days.....

I still have my compressor auto-tank drain which fires every 45 minutes for a couple of seconds.....but virtually nothing comes out any more since adding the aftercooler.

 

[Randy]

My Air compressor runs pretty slow so I very seldom have to drain my compressor tank, maybe once a month or so. I’ve got a friend who has to drain his tank daily, his Air compressor runs pretty fast. So I think the moisture/water build up in the tank has to do with the speed that the air compressor pump is turning and the heat build up. That is a good idea to put a heat exchanger between the pump and the tank with a moisture separator in line.

 

[Rudy]

I could be wrong, but I think the heat is generated by the compression of the air....not the speed of the compressor. (In the same way that the icing is caused by the expansion of the air)

But on the other hand, if the air is compressed SLOWER would that make a difference. Hmmmmm. I'd have to think a spell....

 

[Randy]

It'll still get hot, just not as hot.

 

[MEP001]

I could be wrong, but I think the heat is generated by the compression of the air....not the speed of the compressor.

It's probably a combination of the compression and the friction of the pump running. A slower speed may just give the pump and tubing more time to cool while it's pumping and won't get as hot. It seems like your aftercooler will work better with the pump running at its correct speed.

 

[mjwalsh]

The "cooler" I used is a B&M #70274. It had 1/2" female fittings, which made hookup easy. I bought it online for less than $90. If I remember correctly, it is pressure tested to 200psi and is rated at over 29,000 BTU's.

My fan, a Rotron CL2T2 is just the right size and gives good airflow.

QUOTE]

Rudy,

Thanks. Your post gave us some specifics that seems like really useful info. I did a google search on the "Rotron CL2T2" & it seems to be a terribly hard fan to get --- I wonder if you know of a replacement for that specific fan that would work similar or a better source than what is coming up in google???

MJ

 

[Rudy]

Root around on eBay for either "Rotron Fan" or "EBM Papst" fans. There are a lot of models, sizes and various voltages. My fan is 10" in diameter, which fits nicely with the heat exchanger I described.

 

[Rudy]

I had a crack develop in the aluminum heat exchanger. It turns out that the copper pipe coming from the compressor was transmitting a vibration to the unit which caused it to crack.

I replaced the copper inlet pipe with a braided stainless hose....and all is well. The stainless hose is pricey (compared to the copper), but it's sure cheaper than replacing the heat exchanger.

Here's the unit I used:

http://www.easternmarine.com/36-air-compressor-discharge-hose-142536-0