What do you folks use to keep your compressed air dry?

[Don C Davis]

I have a large California Air Tools compressor, actually 2 of them and the second one in my new shop space generates way more water in the line than the other one for whatever reason--they both have and auto discharge function that purges water from the tank, but other than the small in line filter they came with I don't have anything specific drying the air pumping into the hose. What do you folks do to insure that your compressed air is dry?
Thanks for any input/recommendations!

 

[John Torchick]

Many use a dryer in the line. I release the air pressure every time I use it. Real men read the instructions.....I think.

 

[hockenbery]

I have a water filter on the 1/2” line coming out of the 60 gal compressor.
On water sensitive equipment I have a
A water filter on my air brush
A water filter on my pressure pot for sand blasting
I also drain the compressor tank at the end of the day.

These filters are 5-6” long 2-3” diameter.

 

[Don C Davis]

Well John, the instructions that came with these CAT compressors say that water in the lines should not be an issue with the auto-purge feature that they have and the one filter that is on the compressor--but not so!!I think I'm gonna get some filters like hockenberry spoke of!

Thanks Hock!

 

[Richard Coers]

I don't know any hobbiest that has a drier in the line. Commercial shops use driers, but that's basically an air conditioner unit that runs the warm moist compressed air over a chiller. I have a separator and a desiccant filter. You can bake the desiccant when it gets saturated. At one time I had what is lovingly called a toilet paper filter. It has a roll of brown paper in it that looks like a roll of toilet paper. It does a wonderful job of collecting anything that gets through the water separator. The rolls are throw away. Best advice is to locate those a long distance from the compressor. The cooler the compressed air is when it hits the separator, the better. It's harder to separate water from hot air. I've seen guys mount those right on the compressor, that makes them basically useless.

 

[Bill Boehme]

I have a large California Air Tools compressor, actually 2 of them and the second one in my new shop space generates way more water in the line than the other one for whatever reason--they both have and auto discharge function that purges water from the tank, but other than the small in line filter they came with I don't have anything specific drying the air pumping into the hose. What do you folks do to insure that your compressed air is dry?
Thanks for any input/recommendations!

For supercritical requirements you could go to the expense of adding an intercooler, but that is generally going to excess unless you need absolutely bone-dry compressed air. Another slightly lower cost option is vortex air coolers, but the downside is the need to use a lot more air (and noise) in the process. Two companies that make these devices are Exair and JT Dryers. I have an Exair electrical equipment cabinet cooler that works on the same vortex principle. The lower cost JT Dryer can be found HERE. The operational difference between inter coolers and vortex drying systems is that the intercooler dries the air before it reaches the tank and the vortex dryer removes moisture after it exits the tank.

The typical 40 micron air filters used with air compressors are mostly useless when it comes to removing much moisture and oil mist, but they are good enough for most shop air tools. For painting or piercing I think that the best solution would be to use a coalescing filter preceded by a 5 micron filter. The main purpose of the 5 micron filter is to prolong the life of the coalescing filter. The coalescing filter will remove both moisture and oil mist. Arrow makes a good reasonably priced coalescing filter. Don't use the coalescing filter for nonessential tasks like an air gun or typical shop tools.

Additionally, the tank should have an automatic drain valve to remove any liquid water at the bottom of the tank. There are two kinds of automatic drain valves for the tank ... mechanical valves that work on differential pressure and electrical valves that give you more control over bleeding liquid water from the tank.

 

[Mike Johnson]

Compressed air moisture is a problem for anyone that lives in an area that has average humidity in the air. A multi-step solution is the best approach, an auto condensate dump system at the air compressor tank is the 1st stage, water traps and desiccant filters at the point of use down stream is the 2nd and 3rd stage. These systems only work if they are automated, the manual water traps and desiccant filters never get the routine service required to work properly. For sensitive air actuated equipment we also use in-line air filters to catch any pipe scale before it makes it to sensitive air shuttle valves.

 

[Odie]

I believe condensation accumulating in the lines is resulting from hot compressed air within the line reacting to cooler air outside of the line. One thing that helps reduce the difference between heat within the line, and the outside temperature, is to have a larger capacity compressor tank. That way, the compressed air within the tank has more opportunity to cool down before it enters the line.

I used to have a 20 gallon compressor, and always fought the condensation within the lines. Never had a problem again, once I replaced the compressor with the 80 gallon unit.

I also have an air separator mounted to the back of my lathe. I've never seen any water in the catch bowl, since I switched to the 80 gallon compressor.....

-----odie-----

 

[Lamar Wright]

Don, I see you live in Ga. As you know the Summers here in the Southeast are hot and humid. In my basement shop I installed a dehumidifier and that seemed to take care of my water problem in my compressor.

 

[Jon Minerich]

All good comments. Here is a economical way to minimize (not eliminate) water problems in your tools. Please see my crude sketch.

1. If possible run the output airline from the compressor horizontally to a “T”.
2. Create a “water trap”by dropping 1-2 feet of pipe below the “T”.
3. Add a drain valve at the end of this drop. Like you would do with your compressor tank, drain this daily. This simple trap will collect a good amount of water!
4. Run your airline vertically from the “T” up to your ceiling, or at least 3-4 feet above your compressor. (There is no magic distance, I just run mine up to the ceiling.) The worst thing you can do is run your airline down next to the floor, or even below the output fitting on your compressor. The line will collect water and every time you use a tool, water will come out there.
5. Run your “main line” horiztonal across the wall. Don’t make it perfectly level, put a 1/4” drop from the high side near the compressor, running down hill to the end of your airline. This will allow condensate to run down hill to the end.
6. Drop down vertically where you want a quick disconnect or hook up to your tool. (Yup, the water running downhill from your main airline will travel down this vertical drop.) At the bottom of each drop add install a vortex water filter. Connect your tool at the output side of the filter. You can get these filters at any DIY store for $20-$30. Drain these filters daily. (Please note these filters collect water only if you are using a tool at that location. If you don’t use a tool at that location there probably won’t be any water to drain.)
7. For your airbrushes, etc., add an inline desicant filter. They are cheap insurance. Cheap disposable ones will cost $10, and should be replaced regularly. Professional, rechargeable ones will cost $100+.

Unless you are a professional shop with multiple users of air tools working all day long, you should not have to go through the expense of purchasing an air drier. I can tell your from my experience of purchasing several dryers over the years they are expensive to buy and expensive to operate.

Hope this helps,
Jon

 

[Joseph Maiorano]

I have a 60 gallon compressor. The main line that runs through my shop is pitched back towards the compressor so that any water accumulated in the line drains into the compressor. Each drop comes off the main line with a vertical tee and loops back down. Each regulator comes off the drop, horizontally from a tee. The vertical branch goes to a ball valve where water collects and can be drained off.



The air that comes out is dry enough to spray finishes. I got this from a FWW article some 14 or 15 years ago.

I hope this helps.

 

[Mike Johnson]

These are the auto drain valves we use on our compressed air systems to drain condensate automatically. The system operates on a float valve that cycles after the center cylinder fills with condensate. The condensate discharge can be piped to a drain or outside to keep the floor dry. You could also install a small actuator on your drip leg drain hand valve or install an inline solenoid powered drain valve that could be controlled by a set of contacts on a switch or relay that could be operated manually or automatically by a timer or power source that turns on each day.

A hand valve works great for a home owner or hobbyist, but a business relying on human intervention on a daily basis is another challenge that requires designing the system to be idiot proof which today there is an endless supply of.