Will Oil in Shop Air Lines Damage my Equipment?

Most shop air has oil in it to lubricate the air tools that use it for power.

So, no, but...................

Excessive air could cause problems. Find the lowest accessable drain fitting and remove as much excess oil as possible and you should be OK.

Or break the air line at its lowest point and install a true union drain valve.

is there any painting being done using the shop air?

No - no painting.

Is it true that some pump oil/lubes can damage valves and cylinders?

Couldn't tell you! Is this an automotive shop?

We do some automotive.

I haven't heard of that. I would think that if you're using pneumatic tools that have to be oiled anyway, any compressor oil would be blown out within a couple of uses.

How much oil are you talking about?

Do you have your air discharge line coming from the bottom of the compressor tank?

The one thing that you may have to worry about, is that having oil in your air lines might soften and compromise the rubber lining. You may want to purchase small inline filters to run ahead of your tools. You don't want little chunks of rubber going into your tools.

If that is the case, it won't take long to find out. Your hoses will start developing blisters.

This is a fairly small amount of oil, not causing any noticable change in equipment performance so far. I'm now hearing that the oil in question will not deteriorate Buna/Nitrile seals in our equipment. My goal to to ensure that the effort (including adding coalesing filters) being made is worth it and that it is sufficient to protect our equipment on the floor; However, since it's late in our day, I'll have to confirm the Buna compatability rumor and discuss rubber hose concerns with the maintainence folks tomorrow.

Thanks for the input everyone!

You should be able to go through the list of equipment (valves, cylinders, hoses, regulators and whatever else) and check for compatibility. Some need oil, some don't, but AFAIK most are not too fussy.

You'll probably get most of your answers from manufacturer's websites, but may need to do a bit of 'phoning around.

No problems. Buna-N is fine with oils.

Water is the nasty element. That you have to remove. Generally near the cluster of valves an oil mister/filter is usually placed. Anything with a sliding seal needs oil, but it doesn't need dust and water. Chillers can be used to eliminate the water at the generated source. Automatic drains are placed strategicly throughout the system. We had failures of 3-way valves until I added the oilers. One set of manufactuer's valves had to be cleaned before use because the dust found in them would make a god awful noise if not cleaned. Generally you need to provide a nice place for the discharge of the valve to go. This will have oil in it too.

There's little likelihood the following circumstances exist for you, but for the sake of caution I mention:

1) Breathable air must not contain oil. Don't let amateur divers charge their tanks from your air system.
2) If you have any intensifiers boosting the air pressure considerably, or if you have equipment that heats the oily air it consumes, beware of the Diesel effect. Oily air can combust explosively at high pressures and/or high temperatures. There's lots of info around about the "Diesel air gun" problem.

Mark Bingham
Relativity PL

I have an auto drain valve (periodically blows off, removing any oil and water accumulation in my supply tank) on my compressor tank and it does a pretty good job of removing contaminates. If I need really clean air, I install an additional separator filter at the point of connection for my air hose to the main supply line. I also have a portable separator filter/lube (mist) that I can connect a hose to for any pneumatic tools tools. I'd say moisture would be your biggest enemy. The moisture degrades the pneumatic tools (bearings) in short order. The question: What type of production equipment are you providing the air to?

The problem with making compressed air is the by-product, water.

Even water traps will not remove it completely unless you get dryers, and even then over long lengths of pipework you can still get condensate.

Air oilers are added as the pneumatic pistons, O rings and operating controls need a small amount of lubrication. Is is usually a very light oil, the type I'm sure you can find either by asking your equipment supplier or on line. It also coats pistons and cylinders preventing corrosion from the moisture that may be in your system.

Providing the oil you are finding is compatible with your equipment, then I don't think you have anything to worry about, but check with the compressor supplier to be sure.

From Hydraulics & Pneumatics...

Air lubricators have been an important part of pneumatic systems for decades. Lubrication helps reduce friction between sliding surfaces to not only improve efficiency and increase cycling speed of a component, but reduces wear, which ultimately means longer component life and less maintenance. Moreover, in a pneumatic system, lubrication can reduce both internal and external leakage around valve spools, cylinder rods and pistons, and air motor and rotary actuator vanes, rotors, and housings, as well as other components. This goes for conventional pneumatic components as well as those that can operate with non-lubricated air. Ultimately, the total savings from using lubricated air can exceed the cost of installing and maintaining the lubricators.

Non-lubricated systems

Most of today's pneumatic systems are lubricated. Non-lubricated systems demand more careful selection of components, consistently dry air, and fine filtration. The big advantage of a non-lubricated pneumatic system, of course, is not having to maintain lubricators or keep them supplied with oil. Although lubricated air may boost performance and life of components, it does have drawbacks. First, having to monitor lubrication rates and replenish oil supplies keeps operators from spending time on more productive endeavors. Second, because oil-removal mufflers create a pressure drop, compressors may have to generate slightly higher pressure to compensate for the drop. (This may not be a factor, though, if lubrication increases efficiency of components enough to offset the pressure drop.) Third, the cost of oil used by a lubricated system must be factored into the operating cost. This cost may be offset, though, by longer service life attributed to the lubrication.

Two types of non-lubricated components exist: those that can use non-lubricated air and those that must use it. These components are self-lubricated rather than nonlubricated. The component has a built-in lubrication system that relies on long-lasting solid lubricants - such as PTFE - or has an internal supply of oil or grease that resists being washed away by the compressed air, or a combination of these two methods.

As stated above, components that can use non-lubricated air often will work better and longer if lubrication is provided. On the other hand, lubricated air can have a detrimental effect on components designed to operate only with non-lubricated air.

for the full article follow this link: http://hydraulicspneumatics.com/200/TechZone/AirFiltersandFR/Article/False/21534/TechZone-AirFiltersandFR

Hi j,

I have sold pneumatics for over 40 years and I have been under the impression for most of that time that compressor oil is not good for the seals in pneumatic equipment, due to the cocktail of additives it contains, which can cause seals to swell.

The oil in your lubricators, (if you have any, because the majority of pneumatic valves and cylinders are lubricated for life when assembled), is a low viscosity (VG22).

I have read articles about people in your predicament where they have been advised to remove the pipework and flush it through.

So, if the source of your oil contamination has been fixed, the problem will reduce over time but if you have a problem in a particular area it might be worth doing whatever is necessary/possible in that particular area to solve it.

If the oil contamination has spread throughout your system there is not a lot you can do, time will show if you develop major/minor/or no problems with your pneumatic equipment.

So to sum up, it sounds as if you have compressor oil in some/most/all of your pneumatic equipment. To remove it would be a major task, depending on the size of your installation, because not only would the pipework have to be cleaned, all the pneumatic equipment would need to be stripped, cleaned and re-lubricated.

I do not think you have much choice other than, do what you can in any particularly critical areas and if you have the time and resources start at the compressor and work through the system bit by bit.

The very best of luck,

John

Damage probably isn't the issue. However, compressor oil has different characteristics than tool oil or the oil supplied in lubricators. The compressor oil will become tacky and may cause valves to stick over time. I would install a filter/lubricator upstream of these components.

Thanks to all for the great response and quality of information. I really appreciate this. Seems that each of you are advising some level of caution and that I should get more detail about exactly what the compressor oil is and exactly what the shop valves and cyclinder seals are to create a plan of action. I work on collecting the details next.

There is also a caution about the cost of overreaction, which I really appreciate. Yesterday, our maintenance group installed coalesing filters in crtical areas and reported that they found no/low amount of oil in the lines. We all agreed that we are seeing it in equipment valves - some used for drivers, some to hold parts in place to assist in assembly and testing, some for pick and place robotics.

Again - This has been really helpful - Thank-you all!

Hello J.

Good idea to place coalescers at critical areas. I've run into this before with assembly systems and robotic cells. If you have any venturi style vacuum devices you'll see some accumulation at the exhaust over time which could get messy, possibly affecting your assembly processes.

Most modern pneumatic motion devices used for assembly automation are designed for oil free air, as previously stated, and over time compressor oil can make these pneumatic devices stick. The motion will become jerky, which is not good for your equipment.

In my experience, some oil will always be present in compressed air. I believe it's best to keep oil out of the air distribution system by capturing it just after the compressor, then adding it in a controlled fashion where you need it.

If you are getting oil in your lines, that means oil is getting past the piston rings. This sounds like a bad compressor or maybe too much oil in the sump. Normally an oiler is installed inline to lube air tools. Is there a breather on the oil sump? If not, pressure in the sump will force oil past the rings; not good.

You didn't say what type of compressor. I do know from experience that some screw compressor oils will cause failures of polycarbonate bowls of the filters.

Nothing in any of yours or anyone else's writing was air dryer mentioned. If you have a refrigerated style unit in operation, it should be ok. If you have a desiccant style dryer in operation, you will need to replace the desiccant inside towers. As it has been now coated by the oil and it will no longer absorb moisture.

Good Luck.

P.S.

you might also find out if your compressor was using synthetic oil, this may present a problem with other mineral base oils.

Thanks for that thought..... based on the knowledge of the lead tech, I'm pretty sure that this was addressed, but I will verify.