Dual filters for compressed air

[Silver Heels]

Hey Guys, I am installing the Rapidair 3/4" maxline kit to run new airlines and drops through the shop and have been pondering one thing- I have a regulator/filter combo that in the past has worked satisfactory at best in removing moisture from the air. I am not about run iron pipe or spend hundreds (if not thousands) to try to get my air bone-dry, but I would put a second filter/water separator in line if it would help measurably.

Suppose the filter I currently have removes an ounce of water. Would adding a second filter remove a total of two ounces? Or would the second filter be useless? They would be right next to eachother.

I realize having a second one further down he line would probably be more beneficial, but I am also trying to keep things somewhat simple. Thanks for your input.

 

[600SL]

I think it would help if you put one at each drop. Two close together in the beginning would not be effective.

Another thing you should consider is air oilers. I'm considering teeing in one at each drop with a QD both before and after the oiler. Sometimes you want lubricated air for air tools and sometimes you want dry air for sand blasting.

 

[RickP]

I don't think that type of filter is going to help you that much with getting rid of water. If you wanted to just install something easy, your best bet would be a desiccant cartridge. But a much more effective solution would be a loop of copper pipe between the pump and the tank. If you want to keep it simple, you don't have to put it up on the wall - just a loop in front of the compressor fan with a drain leg would help more than installing a second filter right at the compressor.

 

[Silver Heels]

I considered oilers, but was concerned about contamination in the lines if I paint. Plus adding a drop of lube to the tool every so often takes seconds. I see your point though, a guy could have an oiler at the drop with a dedicated paint hose and give his tools a steady supply of oil rather than sporadic douses.

Has anyone here tried to run two filters back to back? Did you get any amount of water out the second one? If not I may try it and post my results. Worst case scenario it doesn't do anything, I'm out 30 bucks and the time it takes to give it to someone who needs one.

 

[Denwood]

My setup has two outlets..one for painting, and one for everything else. Pretty easy setup really. The paint air setup was originally used to supply very clean/dry air to clean optics in our clean room. It's since been relegated to my shop. The full setup with two filters and desiccant etc is about $800 or so new.

 

[Silver Heels]

Thanks for the replies. I'll save my money for something else. I do have a perhaps hair-brained idea for cooling the air between the compressor and the filter though. The compressor sits next to the utility sink in the basement. For times when I am sanding, sandblasting, or painting, What about plugging a 50 ft air hose in between the compressor and filter, dropping it into the sink and covering with ice? Obviously not something I'd do if I am just pulling a rivet or two, but may help for when the compressor spends half the time running. Thoughts?

By the way Denwood- nice looking setup you have. I appreciate the time you took to show how you did it. One of my yearly rituals is taking the bike through Thunder Bay and around Superior. Ever take the family camping at Sleeping Giant? Beautiful area.

 

[redmondjp]

Thanks for the replies. I'll save my money for something else. I do have a perhaps hair-brained idea for cooling the air between the compressor and the filter though. The compressor sits next to the utility sink in the basement. For times when I am sanding, sandblasting, or painting, What about plugging a 50 ft air hose in between the compressor and filter, dropping it into the sink and covering with ice? Obviously not something I'd do if I am just pulling a rivet or two, but may help for when the compressor spends half the time running. Thoughts?

By the way Denwood- nice looking setup you have. I appreciate the time you took to show how you did it. One of my yearly rituals is taking the bike through Thunder Bay and around Superior. Ever take the family camping at Sleeping Giant? Beautiful area.

Your idea is not a bad one, but the air hose will not transfer heat well at all - if you're going to do this idea, do it with a coil of copper tubing (1/2" dia) and put a water separator on the outlet of it. Copper is one of the best heat-conducting materials.

 

[akdiesel]

A lot of this depends on your location. Humid areas like Florida will need some sort of addtional support like a desicant.

 

[kansei]

Something I read years ago (but have seen many setups to the contrary), is that compressed air at 90psi, and ambient shop air temp of 80*F with "average" humidity levels requires a minimum of twenty feet of air line travel before water will "efficiently" condense out of the air. I can't recall where I read it, or if it is accurate or not, but basically it contradicts most guys' setups here that have a drier just inches or a few feet at most from the compressor outlet. I have also heard of people using the coiled copper pipe idea where space is tight to help get a longer run from the compressor to the drier- again, supposedly to aid in extracting more moisture from the air.


Neal.

 

[Denwood]

Silver, we spend our summers, short as they are, traipsing around in our Westfalia. The kids have grown up exposed to pretty amazing geographic karma I proposed to my wife on the chest of the Sleeping Giant, on 700ft cliffs overlooking the lake Having travelled a fair bit of the globe, Thunder Bay in August (when the skitters have gone to bed!) is pretty hard to beat.

Your idea of a chiller is pretty much in line with industrial versions that do a similar job. You just need to make sure the hose can drain back into a separator, and empty it often. The filters on the Devillbiss empty automatically so something along those lines would work great at the base of your DIY chiller tubing.