Air line moisture options

[SirLesPatterson]

In my home shop I have a 60 gallon air compressor piped to 5 outlets. It has worked well but I think I should do something about moisture before I get a plasma cutter. It would be nice to have a unit that attaches at the air compressor and handles the whole system and also to minimize consumables. I see systems that use dessicant and are there others that don't? What do you all suggest? I'm in my shop almost every weekend but don't always use the compressed air. Things get humid around here too. Thanks.

[jlevie]

I have no idea what your setup looks like, but I find it best to have a regulator (set at 90psi) between the tank and the air lines. I also have a filter/separator between the regulator and the lines. The expansion from tank pressure (150psi) to line pressure condenses a good bit of water out. It also helps to regularly drain any water from the tank. To make that easy I replaced the petcock with a ball valve and tygon tubing that goes through the wall to the outside. I try to drain the tank weekly. The valve and drain line makes that easy.

There are three ways to reduce air line moisture. The simplest (and least effective) is a radiator like thing between the line regulator and the lines. For it to work there has to be pressure drop and expansion cooling. Next up are the desiccant dryers. They work but the single chamber types require frequent changes of the desiccant. There are more complex (and more expensive) types that have two or more desiccant chambers, each with a heater, and a control system that cycles between chambers and drys one out while another is in use. The most effective (and most expensive) is a refrigerant system that chills the air below the dew point.

In a home shop, where cost is a big consideration, I'd go with a setup like I have (regulator & filter/separator) and use a small desiccant dryer between the air line and the plasma cutter. The best of those allow the cartridge to be refilled. Which means you can bake the used desiccant and dry it out rather than just replacing the cartridge.

[davidh]

I have a Motor Guard canister water filter on my plazma, I change the paper trap every year of so.. about $10. the new unit is about $60. prior to that I used a disposal plastic paint gun filter. that worked fine also, only cost a few bucks and got replaced about every 4-5 months. but this depends on how much you use your plazma. if I were to try to filter the whole shop, I'd be spending a ton on filters. most of my usage is blowing things off or an occasional air tool. a bit of moisture does not effect them to badly. works for me.

[Lu47Dan]

I have a Motor Guard canister water filter on my plazma, I change the paper trap every year of so.. about $10. the new unit is about $60. prior to that I used a disposal plastic paint gun filter. that worked fine also, only cost a few bucks and got replaced about every 4-5 months. but this depends on how much you use your plazma. if I were to try to filter the whole shop, I'd be spending a ton on filters. most of my usage is blowing things off or an occasional air tool. a bit of moisture does not effect them to badly. works for me.

+1, I have one mounted on my Milller 2050. But I do not get large amounts of moisture in my system as I drain it at the tank my supply line from the compressor to the system in the shop is pitched back to the tank.
Dan.

[bfjou812]

Along what has already been stated, I have put a drain leg at each of the outlets with a ball valve to drain the water. The way I did it was using 2 tee fittings with one facing up -that was for the coupler, and the other facing down for the leg, attach a piece of pipe about 18" long with a ball valve attached. I also had a drain leg between the compressor and the filter.

[ironmonger]

I have no idea what your setup looks like, but I find it best to have a regulator (set at 90psi) between the tank and the air lines. I also have a filter/separator between the regulator and the lines. The expansion from tank pressure (150psi) to line pressure condenses a good bit of water out. It also helps to regularly drain any water from the tank. To make that easy I replaced the petcock with a ball valve and tygon tubing that goes through the wall to the outside. I try to drain the tank weekly. The valve and drain line makes that easy.

There are three ways to reduce air line moisture. The simplest (and least effective) is a radiator like thing between the line regulator and the lines. For it to work there has to be pressure drop and expansion cooling. Next up are the desiccant dryers. They work but the single chamber types require frequent changes of the desiccant. There are more complex (and more expensive) types that have two or more desiccant chambers, each with a heater, and a control system that cycles between chambers and drys one out while another is in use. The most effective (and most expensive) is a refrigerant system that chills the air below the dew point.

In a home shop, where cost is a big consideration, I'd go with a setup like I have (regulator & filter/separator) and use a small desiccant dryer between the air line and the plasma cutter. The best of those allow the cartridge to be refilled. Which means you can bake the used desiccant and dry it out rather than just replacing the cartridge.

pretty much +1

The only place I would disagree with is the bit about "most effective' relating to refrigerated dryers. Desiccant dryers can yield dew points below -90 degrees. That's effective.

In the medical gas community the desiccant dryer folks almost snuck through a provision that required medical air have a dew point no higher than 0 degrees... which is impossible to achieve with refrigerated systems.

Adding a timed automatic tank drain has helped me. I often neglect to drain the tank on my own some automation helps there.

paul

[Mike Amick]

I find it best to have a regulator (set at 90psi) between the tank and the air lines. I also have a filter/separator between the regulator and the lines. The expansion from tank pressure (150psi) to line pressure condenses a good bit of water out.

Just curious .. why run your compressor at 150 if your max needs are 90.

Mike A

[JoeFin]

Treating the air / removing moisture before it goes into the Air lines of your shop is your best option. Eleminates the possibility of creating rust/contaminates in your system. Could be as simple as 1/2" soft stainless steel line coiled into a bucket of water or as costly as the refrigeration/heater type dryers.


I agree Desiccant dryers with changeable canisters are your best option.

Followed up by a simple separator/filter at the outlet and you should be in good shape

[MichaelP]

I run a 5hp Quincy followed by a pressure regulator(down to 90psi)/filter and a 40'-long zig-zaged copper pipe radiator. This alone gives me a very dry air in the moisture laden WI woods. However, being anal retentive, I installed dropdowns with drain valves in every branch along with a proper pitching of all distribution lines, automatic tank drain and large desiccant dryer (a lowly Harbour Freight product). It's installed at the outlet feeding my sandblaster and plasma. Both of those also have their own regulators with filters.

But, again, I have never seen any accumulation of moisture after the radiator run (besides its own drain, of course). My gut feeling is that a 20'-long radiator would be sufficient (especially, if made out of larger diameter pipes).

[Royldean]

Just curious .. why run your compressor at 150 if your max needs are 90.

67% more air in reserves? Less compressor cycling?

[edit] oh, and the "expansion cooling" drying methods won't work if there is no regulator?

[Bob Fisher]

I don't believe it was mentioned, but if you can, take the air off the top of the pipe by means of an upside down "U". Let gravity be your friend. Bob.

[darryl]

Not an experts opinion- just thinking out loud here. I always have thought that when the compressed air coming off the pump goes into the tank, it takes the heat of compression with it. I think this should be removed before it goes into the tank. That would mean that the 'hot' line should be cooled and the moisture condensed out before the compressed air enters the tank. It might get to be a plumbing nightmare, but I like the idea of having a cold water line entering a tank which contains a heat-exchanger network of copper tubing through which the compressed air goes. A 'moisture catch' and drain valve would be integral with this, and the cold water entering the tank would go on to the buildings' systems- toilets, etc. Everytime water ran for a toilet flush, hand washing, etc, the coolness in this cooling tank would be refreshed. You might even have a temperature sensitive valve that would flush a few gallons through if the tank temperature rose above some certain temperature. This might be required if you're running the compressor a lot and not using water during that time.

On the other hand, you could have a cycling loop where you don't waste the water- instead you cycle it through the loop and the heat dissipates into the room air from the loop.

In any event, past this initial stage of air drying, you would still use the standard filters in various places, and use drop loops with their own drain valves.

[Plain ol Bill]

Here is a good suggestion. I made one similar to it and absolutely love it.

http://www.plasmaspider.com/viewtopic.php?f=12&t=10757&p=58687#p58687

[Mike Amick]

67% more air in reserves? Less compressor cycling?

[edit] oh, and the "expansion cooling" drying methods won't work if there is no regulator?

I actually have mine set similarly, just seeing yours in writing made me think.

This does pose another question or Mod ... Its annoying when I go to fill up my portable tank
and I can only get it up to 90 when I know there is like 140 at the compressor. I use if for my nail gun
and if I could get it up to 125 or so .. I could nail longer. Maybe there ought to be a tap before
the regulator just for this purpose.

Mike A

[vpt]

Here is a good suggestion. I made one similar to it and absolutely love it.
http://www.plasmaspider.com/viewtopi...p=58687#p58687

I am interested in something like this. There are times I could take a shower with my air hose.