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Thread: Help! Getting the oil out of my compressor lines

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    Default Help! Getting the oil out of my compressor lines

    Well, I never really "designed" the air system in the shop, just have hoses running about and today it bit me in the butt. I have a fixture that uses pneumatic solenoids to fixture a part. I guess oil got into one and killed the solenoid. I tried to take it apart and clean it out to no avail - some tiny tiny parts inside were galled and bent. A new solenoid is $176! Luckily I found some used but working ones on ebay - four for $15! (woohoo!).

    Anyway, it illustrated the fact that I *really* need to get the oil out of my air lines. Its a Jun Air compressor with 6 rotary screw heads and it chows through oil like a mofo.

    I bought this on eBay just now

    http://cgi.ebay.com/ws/eBayISAPI.dll...tem=7616722676

    But I am not sure that's gonna do it, although I am sure it will help. I have one machine in particular that needs really clean air, so I was thinking of putting a piece of copper pipe on the wall vertically, about 6 feet long, then having a U on the bottom and the air comes in one side of the U, goes all the way up the pipe, then back down a few feet and into the machine that needs the dry/clean air. The idea being that the copper pipe will take heat out of the air and also help the oil/water fall out of suspension and gather at the bottom of the U. Then in the bottom of the U, I'd put a purge valve to drain it out once every so often. Then going out of my piping it would go into the filter above I just bought then into the machine.

    What do you guys think? Will that get me nice clean air free of oil? If you think that would work, maybe I could build the oil seperator copper-pipe thing over at the compressor and allow myself nice clean air to all machines, instead of just the one?

    While I'm asking ?'s, does anyone have a good way to flush out air hoses that have oil in them due to oil from the compressor condensing in the air hose? I was thinking I could hook up an oil luber to the start of the air hose but fill it with degreaser and blast air/degreaser down the hose, but maybe thats bad? I'd hate to eat away the lining of the hose or have some degreaser residue left in there when I hooked it back up to my machine.

    Any ideas?

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    An ounce of prevention is worth a pound of cure but it is too late for that.....

    I bought a moisture trap one time and in it they had a schematic for an air system. The lines were slanted and T'd so that any oil that dropped out of suspension would drain BACK to a low point near the compressor so it could be drained off.

    Also, any line "drop" was T'd in out of the TOP of the main line (instead of the bottom) - fluid's don't tend to gravitate UP....

    However this usually means you have to redo the whole system - why didn't I find the schematic BEFORE I plumbed it rather than after???.... Typical.

    Since replumbing is probably out of the question, you're probably going to have to mount any number of traps in the system.

    Better yet, DON'T put the oil into suspension in the first place - perhaps fixing the mofo compressor might be a good place to start....

    Tramp oil in the system not only traps itself but it also traps moisture. Moisture and oil plus hot air (compressed air is quite warm) is a PERFECT environment for rust and corrosion and crud to form.

    Oil that gets into rubber hose starts a deteriouration process that is not reverseable. It is probably better to toss the hose that to try to 'clean' it... With the cost of hose from Harbor Freight and other distributors anymore, it is a commondity like kleenex to be used and tossed....

    If the degreaser idea worked right off, great. But where do you dump the goo that it will dislodge??? Toxic crud blown into the shop is hardly a good place to let it fly. Then, if you merely loosen a remote chunk and DON'T remove it, it will inevitably come loose and create havoc later on.

    In a small shop, it might simply be cheaper and easier to replumb. Consider plastic for "hobby" work as it will withstand the burst (under 125 psi working if you buy the right stuff). IT is easy to fab and cheap compared to steel. I"ve had it in my garage for nearly 12 years and asside from the OOPS of overtightening a threaded fitting, it has been trouble free.

    But in light of what you've bee through, you learned all of this already,

    Regarding the oil separator idea, trap it as soon as possible as opposed to contaminating the system.

    You've already outlined the appropriate fixes hence you already know what to do. What more convincing do you need asside from the problems you've already had???

    Why should you beat your head against the wall??? Simple. Because it will feel so good when you quit....



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    Quote Originally Posted by SRT Mike
    ...Anyway, it illustrated the fact that I *really* need to get the oil out of my air lines. Its a Jun Air compressor with 6 rotary screw heads and it chows through oil like a mofo....
    Not only do you need to get the oil out you need to prevent it getting in the lines in the first place.

    Rotary screw compressors run in an oil bath which forms the seal in the screw and they have the separator to strip the oil out and recycle it. I have a big rotary screw that consumes about 1 quart a week and have been told this does occur with older rotary screws because the oil separator on the machine loses efficiency. The fix is to get the oil separator replaced.

    Maybe you should get someone to look at your compressor as a first step.

    Your copper pipe idea will work but the best thing is to do it correctly with a refrigerated air dryer right at the compressor.

    And if you have an urge to play Russian Roulette use plastic pipe. Seriously; plastic pipe will not meet any OSHA inspection and if anything happened with your air system you would be in deep trouble. The big problem with plastic is that when it fractures it tends to go whole hog, the fracture spreads along the pipe and spreads fragments of plastic all over the place. In the extremely remote chance you get a burst steel or copper air line the fracture does not spread.



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    I don't mean to sound like the compressor is leaking like a sieve, it goes through about a quart every 2-3 months, but it seems like most of that quart goes into the air lines. The compressor is almost new - just out of warranty and has gone through this much oil since it was new. Jun Air tells me I'm well within normal limits. I think the problem is that I have air hoses strewn about the floor going to the mill, the lathe, the other machines, etc. I have an pneumatic fluid dispenser on one desk with a vent tube out the bottom. I noticed that over a period of 2-3 months I have a little puddle of goopy compressor oil coming out of it. We're talking maybe a tablespoon of oil over a few months, but the air solenoids on my fixture are quite small so this amount of oil is above what's acceptable.

    I am not aware that my compressor is equipped with an oil seperator? It has an automatic purge valve on the bottom of the tank that occasionally purges water and oil that's gathered in the tank. But beyond that the compressor units are on top of the tank and feed down into it, then there's the regulator assembly then out to the lines. Rather than spend a lot on a seperator/chiller, I was thinking I could use that "oil seperator" I bought on eBay along with my copper pipe idea and it would be sufficient.

    I agree about not using plastic around a shop. I've always heard copper is the way to go. We do move some heavy stuff around here and I've heard that when plastic pipe gets hit, it explodes sending shards everywhere. I already pay enough for general liability insurance and workmans comp, so the last thing I need is to create a foreseeable potential risk that could hurt someone.



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    Use a coalescing filter to remove oil from compressed air. They filter down to .01 microns and follow that with a condensate/general purpose filter. If your compressor puts out large amounts of oil then two or more coalescing filters may be needed. Using auto-drains on your filters is recommended unless you feel like manually draining filters daily. If the oil problem is so bad you may need a new compressor.

    There is no line cleaner that I know of that is safe to use. I would not recommend using a solvent based cleaner and compressing it, even though solvents do a good job of cleaning things.

    That item that you got off of Ebay (larger tank) lookes to be a dessicant drier. If so, it is filled with dessicant beads and once they get coated with oil they become useless. Dessicant beads work by absorbing water out of compressed air.

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    When we moved into our shop, it was already fitted with plastic pipe for air. It is all up and out of the way and you'd have to work real hard to hit it with any equipment. My garage at home has it and it is going on 12 years... I used high temp 300 psi rated plastic and run it at 125psi.

    A quart of atomized oil would leave a mess just about anyplace if spread out over 100 to even 2000 sq ft - do that every month and you have a real mess. Think about it if confined to 3/4" pipe stretched over say 100 foot running length. A mess no matter how you distribute it or try to contain it.....

    No matter what, it is easier to keep it from getting distributed than to try to contain it after the fact.

    The problem with copper is that it will eventually work harden from cycling from atm to 120 or so psi. The only stuff rated for infinite life is steel pipe.

    Whether it is water or oil, compressed air will ultimately precipitate out oil or water. Simple function of the compression process. The trick is to force it to separate out where YOU want it to as opposed to where it wants to.

    It is a thermodynamic fact that as it (air) cools, the liquid will precipitate out (this is a function of the dew point and the amount of fluid suspended and how much can be suspended at that mass at that temp before its gonna drop out. Simple thermo principles that can't be avoided or gotten around.

    Add the traps, driers, etc and the problem can be contained. Or find a compressor that doesn't add the 1 to 2 qts per month as "normal" wheppage.

    Choice of the options remains yours but you have the choice of NOT putting the oil there in the first place or else finding a way to strip it out once its there seems to be your 2 most viable options.

    Your choice???



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    Did I miss seeing this suggested somewhere in your post? "using a solvent based cleaner and compressing it". EeeeK!!!!! Don't do that. I saw a photograph of a 100 gallon air tank that exploded and the conclusion the Work Safety people and the Fire Department came to was that it had taken in solvent fumes and compressed them with the air. It knocked a 20 feet by 10 feet hole in a concrete block wall and one piece of tank landed 1/4 mile away.

    2muchstuff's suggestions are the way to go. I am surprised that you have a new rotary that uses oil. I have two; a 60cfm unit that has done 45,000 hours and as I said uses a quart a week on 24 hour operation and a 30cfm unit with 6,000 hours that does not use any oil between oil changes.

    I suggest don't even bother trying to clean your existing lines. Plumb everything with copper and run new drops to your machines. It is worth it, I saw the light a year ago and have not had any air problems since doing it.



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    If I knew how to post a quote I would but I said that "I would NOT recommend using a solvent based cleaner".

    I work with air compressors as part of my daily job and Jun Air compressors are not on the top of my list. Few units last a long time with no problems but most of them never last as long as they should with a past history of major problems. All of the problems include passing major amounts of oil.

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    Quote Originally Posted by 2muchstuff
    If I knew how to post a quote I would but I said that "I would NOT recommend using a solvent based cleaner".

    I work with air compressors as part of my daily job and Jun Air compressors are not on the top of my list. Few units last a long time with no problems but most of them never last as long as they should with a past history of major problems. All of the problems include passing major amounts of oil.
    Click on the QUOTE button in the bottom right of the post.

    I have to apologise; I phrased my post poorly. No you did not suggest using a solvent but I thought you must have read somewhere in one of the other posts that this had been suggested.



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    You can install a coalesing "not sure of the spelling" filter at the point of use. Depending on the volume you need it will cost a little or a lot. Check Grainger's web site and see the mulitiude of filters there. The coalesing filter removes oil and water.



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    maybe i totally missed the point over here but,

    i got some degreasing stuff they call "cold degreaser' over here. its used in car shops alot, to spray on greasy parts under the hood and it goes right into the tank of a spraygun. i guess you should keep it away from your compressors air inlet

    please feel free to correct/inform me if i'm wrong or creating anykind of a dangerous situation as i care alot about my safety.



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    Cool piping

    Go to tptools.com. It has a load of info on air systems. They reccomend black pipe for air lines. Reason given is warm air hitting cold pipes condenses moisture out of pipe. Always slope pipes downward toward compressor so moisture drains into tank. Use water and oil seperator then a coalesing filter in line. This is what they reccomend for their sandblast cabinets. There is a diagram on their website that shows everything. Maybe this will help. copper is not reccomended.



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