Refrigerated air drier ??

[Russ Buddle]

We have been using more and more air in my shop building rustic country furniture. We are now up to a 3 man operation, and some days use a lot of air. I am usually spraying most of the day, and one man is using an air RO sander off and on, and both of the guys are nailing and stapling. My compressor has no problem keeping up, but on humid days the water seperators do not do their jobs fully. Getting a little bit of water vapor coming through the air lines.

I really do not want to spend $1500 for a commercial drier.

I have an apartment sized refigerator i can use to make a drier. I was thinking about drilling a hole in the side of the fridge near the top, and making a square coil of 1" copper pipe (90 deg ells, and straight pipe)decending to the bottom of the fridge, then out through the side into a water seperator, leaving a vertical drain space with a petcock before the seperator.

Does anyone have any input ??

[Matt Meiser]

I've seen an air-air aftercooler built from copper tubing wound around a plastic bucket as a temporary form that the builder said was very effective. It cools the air leaving the compressor head before it enters the tank so the water can drop out in the tank.

And I've seen a water-air cooler built inside a trash can that the builder filled with ice water. That would be similar in concept to what you want to do.

Finally, how about a used commercial dryer. They show up on Craigslist from time to time around here. I think there's one for $500 right now.

[Mike Golka]

You would likely be better off using coils of copper tubing. You will need a lot of suface area (long length of tubing) to cool the air suficiently and keep up with the demand. A desicant system may work better.

[Gary Pennington]

An air-air aftercooler with an electric motor driven fan blowing over the cooler coils between the compressor & tank will do wonders. I used one in my hydrostatic transmission reman shop and it did everything we needed. Near zero maintenance also. Water to air coolers are even more effective.

[Chris Parks]

First things first is the size of the pipe in the workshop. If the pipe is large enough the air speed is slowed down and the water is less inclined to travel with the air, small pipes = high air speed and good water suspension. I was told to use at least one inch pipes to overcome this.

The fridge idea is one I have proposed before and my idea was to put a portable air bottle in it, your needs sound like that might not be enough but it would help. What may work better is a large standalone vertical receiver where the air stalls, cools down and is collected and just park it in the corner somewhere. I would think using the fridge idea that a copper coil of at least one inch would work but collecting the water out of the coil might be problematical though I guess if the drain were at the bottom the water would drop down through the coil. It would be cheap to do and take about an hour so I guess there is no real downside to it. I would be interested in what you do and the result.

[Russ Buddle]

I think I will have time this weekend to put it together. I will try it out for a few days next week, and post results.

Thanks to all who posted on this thread.

[Tullie Templet]

A buddy of mine paints cars for a living and he uses an old hot water heater as a condensate drop out. One line is short and the other line goes to the bottom and the drain is already built in. And I work with an ex-plumer that said the tanks are rated for like #300 so that isn't an issue. Then put the driers after the tank. That is what I am going to do when I set mine up.

[David Cefai]

You need to consider that air heats up when compressed so that its Relative humidity is reduced (can pick up more moisture). When it cools down the RH rises again, possibly to condensing levels.

Consequently it may help to look at what you want to do as a 2 step process.

1. Cool the hot air.
2. Remove the moisture.

Best would be to cool the air to below ambient to promote condensing out the air.

The fridge will do this but you may find that a long line between the compressor and the fridge, possibly cooled with a water spray and a fan, will improve the efficiency of the drying process. The air will enter the fridge cooler and therefore will be able to be cooled even more.

When the air warms up again after the fridge you will have an even lower RH.

[Faust M. Ruggiero]

You are a business with employees. You pay them by the hour. You buy tools for three men. One drop of water on a finish can ruin it. Moisture in your pneumatic tools will shorten their life. Even a high quality sander will spit water on a finished surface. Buy the refrigerant cooler. I have them in all our buildings with compressors. They are not cheap to buy and draw electricity to run but your air will be clean. I wouldn't even consider a used one. Shop Grainger and buy one suited for greater capacity than your present compressor. You will increase cfm consumption as you grow. Be ready for it.
fmr

[John A langley]

Faust - He hit the nail on the head so to speak. Buy the commercial drier. This is not a good place to save pennies. All your air tools will work better and last longer.

[Chris Parks]

Better yet, get someone who knows what they are doing to design a system that works, it will cost you less in the long run. People think you just put up some pipe and that will do it but there is a whole lot more than that to it. You need big pipe, no low spots to pool water and it goes on from there. Safety issues are always present also and compressed air is deadly. I saw a person injured because a boss used the wrong style of quick coupler, as it was dragged across the floor it snagged and uncoupled and the high pressure side of the hose went nuts and hit the operator. The insurance company were not amused.