Air Compressor Moisture Removal Ideas

[egon]

I was wondering what you all are finding works well for moisture removal in your shop air.

My set up is a 18.5 cfm, 60 gal unit and the most it would be used for is occasional sand blasting, DA sanding and painting. My shop isn't too large so I don't have any hard lines plumbed and I can get to where ever I need to with about a 30' hose direct off the tank.
I know that a dryer on the tank really wouldn't help much but I don't really want to plumb the shop just so that I can put a dryer at the end of the line because where the compressor is now works great for my air needs. I guess I could plumb something up then across the ceiling and back but that seems wasteful.

I've read that some guys use an A/C condenser at the compressor to cool the air and then install a dryer which seems like a decent idea. Not sure what else is being used so any ideas are appreciated.

Thanks.

 

[sberry]

Has it been a problem yet?

 

[The Cobbler]

a drier doesn't have to be at the end of the line. as long as the air has cooled, once the moisture is removed that's pretty much it.

 

[mday1]

I installed one of the auto drain HF kits years ago. Last year I began wondering if it was doing its job and remove the drain plug, and not a drop of water cane out.

 

[C lectric]

I made an aftercooler of sorts from copper tubing several years ago. It simply sits on the floor held upright by a wooden frame. If need be I can aim a fan at it to help if it ever shows signs of warming. TO date it has served me well.
My machine is smaller than yours at 3HP and 20g tank.

I used 3/4 copper tubing. Theory being that one way to drop entrained water is to slow the air movement down by a large bore and splitting the flow. Then a vertical rise on two sides to the top mounted outlet. Water will collect in the entry horizontal tube, get pushed to the verticals where it will drop to the lower horizontal so it can be drained.
Also the tubing length will cool the air inside promoting more water dropout.

You could do something similar with longer runs and maybe one size up tubing to 1". My copper tubing was used although in good condition. I did have to buy a few fittings.

A crude dwg. is attached. Sorry cannot upload dwg. crude as it is.

I will try describe it.
12" tall, 9" wide.
3 horizontal tubes, bottom is the drain, middle tube is the compressor inlet, top tube is the air outlet. All inlets/outlets mounted in the centre of each horizontal tube.
The middle tube, inlet is mounted 4" up from the bottom tube.

 

[egon]

Has it been a problem yet?

Now that's a question I've been thinking about the past few weeks and my answer is "I don't really know".

We moved to our new place last summer and where we lived before, the shop was only 20 x24 so I had the compressor outside in the garden shed and plumbed to the shop. Plumbing was about 25' long and at the end was my dryer and I took my air from there. I don't recall any real moisture issues with that set up but then I was only doing panel repaints and didn't have a sand blaster so the compressor only ran for short times.

I guess I could just run it the way it is and see but I would rather start with a proper set up instead of having to sort it all out later. For what it's worth I now drain about 1/4 cup of water from the tank for every hour of actual run time.

 

[sberry]

What's to "sort out later". At this point it's speculation, so much easier if a guy knows what the actual problem is vs shotgun approach?

 

[American Locomotive]

What I found is that the coalescing air dryers/moisture separators become ineffective if the incoming air starts to get hot. They remove adequate moisture as long as the air in the tank stays cool. So no issues with intermittent work.

Our problems started occurring when we got a blasting cabinet and kept the compressor running for sustained periods of time. Eventually the air outlet at the compressor tank would get warm, the moisture separator would get warm, and even the air lines would get warm. At that point the moisture separator wasn't doing anything and the air nozzle in the blasting cabinet was basically a garden hose.

We cobbled a big aftercooler onto the compressor outlet before it went into the tank, and it made a huge difference with sustained blasting. The tank would stay cool, and the moisture separator would collect tons of water.

 

[egon]

Thanks Guys, so I guess I'll start looking into an aftercooler of some sort because it's worked for C lectric and I'm speculating that my tank will get warm as did American Locomotive's did when I do lots of blasting and the compressor is running more.

sberry, do you have anything else to suggest other than wait and see? It's so much easier to plan ahead to prevent a poor paint job that was caused by moisture in the lines than to redo the job afterwards.

 

[vavet]

There was a thread on here several years ago talking about a device known as the Franzinator. Some people swore by it, others not so much. Google it and see what you think.

Here’s what I did for an application at work. I took 3 sticks of 10 foot 3/4” copper pipe. I cut them into 5 foot lengths and made a zig pattern out of them and plumbed air into it after it left the tank. The idea was I wanted a big heat sink to encourage moisture to fall out. I have a ball valve on a vertical leg at the bottom, but the truth is that I never get much water out here. Most of it still comes from the air compressor tank itself.

 

[redmondjp]

Fan-cooled aftercooler, which is an option on the higher-end compressors. Search on this site, this topic has been discussed in detail.

 

[engineer2]

Some depends on how humid your climate is, and how critical the quality of your painting needs to be.

 

[MoonRise]

Cooling the air is never a bad idea.

Just by cooling the air you will get some (sometime a LOT) of the moisture in the air to condense out.

But you will often still need some sort of actual air DRYER for 'critical' purposes.

A refrigerated air dry usually works well (size and install it properly).

Or you can use a desiccant air dryer (again, size and install it properly).

 

[sberry]

The question is,,,, what is critical?

 

[matt_i]

I haven't hooked up the sandblast cabinet yet...so take that unknown, but it is painting very well.

The big copper array is designed to assist with cooling, I used 1" NPT cyclonic then 1" coalescing filters. I also make the air go up ^ for a ways before going back down, thats designed to capture initial moisture after the tank + 2 filters.

Then right by the paint area...meaning I drag a hose outside to paint on sawhorses far enough away that the overspray doesn't strike the siding... I have a dessicant filter and another 0.5 micron coalescer. There are filter elements down to 0.1 micron but would be at extra expense and I wanted to see how well it does like this.

All components other than the copper are either NIB or good-used from ebay. The system was a long time (meaning probably 8 years) in development but is finally coming to fruition and I'm glad to have it. Previously I used a system of hoses and remote filtration.

One thing I really like about this is the extra volume stored in the pipe system. It definitely requires a lot more time before the compressor recycles when just inflating tires as a baseline.

 

[csp]

There are a few aftercooler threads in the General Garage forum.

 

[FTG-05]

There was a thread on here several years ago talking about a device known as the Franzinator. Some people swore by it, others not so much. Google it and see what you think.

Here’s what I did for an application at work. I took 3 sticks of 10 foot 3/4” copper pipe. I cut them into 5 foot lengths and made a zig pattern out of them and plumbed air into it after it left the tank. The idea was I wanted a big heat sink to encourage moisture to fall out. I have a ball valve on a vertical leg at the bottom, but the truth is that I never get much water out here. Most of it still comes from the air compressor tank itself.

Franz, the so-called inventor of the Franzinator, used to be a member here, as well as Shop Floor Talk, Pirate4x4, and a couple other forums et al. AFAIK, he was eventually banned from all of them.

Having said that, I made two "franzinators" for my compressed air systems.

The first, was a ~5' long 5x5" square tube with 1/4" plates welded to the ends. I made this way back in 1999 or so and I still use it today.

The 2nd was a 120 gallon compressor horizontal tank I converted to vertical to save space.

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