6 Basic Steps for Good Air Compressor Maintenance (And When to Do Them)

A production equipment mechanic with the 76th Maintenance Group, takes meter readings of the oil pressure and temperature, cooling water temperature and the output temperature on one of two 1,750 horsepower compressors. (Air Force photo by Ron Mullan)

In one of my previous jobs, I was responsible for the operation of the facility.  One of my biggest responsibilities was the air compressor because it supplied pressurized air though out the facility to feed the pneumatic systems.  Like with many industries, the compressor system is the life blood of the company.  If the compressor fails, the whole facility will stop.  In this blog, I will share some preventative maintenance items and schedules for your air compressors.

Because the cost to make compressed air is so expensive, compressed air systems are considered to be a fourth utility.  And with any important investment, you would like to keep it operating as long and efficiently as possible.  To do this, it is recommended to get your air compressor a “checkup” every so often.  I will cover some important items to check as well as a recommended schedule for checking.  Depending on the size of your air compressors, some items may or may not apply.

1. Intake filter:  The intake filter is used to clean the air that is being drawn into the air compressor.  Particles can damage the air pump mechanisms, so it is important to have the proper filtration level.  But, as the intake filter builds up with debris, the pressure drop will increase.  If they are not properly monitored and cleaned, the air flow will be restricted.  This can cause the motors to operate harder and hotter as well as reduce the efficiency of the air compressor.

2. Compressor Oil:  This would be for flooded screws and reciprocating compressors that use oil to operate the air pump.  Most systems will have an oil sight gauge to verify proper levels.  In larger systems, the oil can be checked for acidity which will tell you the level at which the oil is breaking down.  The oil, like in your car, has to be changed after so many hours of operation.  This is critical to keep the air pump running smoothly without service interruptions.

3. Belts and Couplings:  These items transmit the power from the motor to the air pump.  Check their alignment, condition, and tension (belts only) as specified by the manufacturer.  You should have spares on hand in case of any failures.

4. Air/Oil Separators:  This filter removes as much oil from the compressed air before it travels downstream.  It returns the oil back to the sump of the air compressor.  If the Air/Oil Separator builds too much pressure drop or gets damaged, excess oil will travel downstream.  Not only will the air pump lose the required oil level, but it will also affect the performance of downstream parts like your air dryer and after cooler.

5. Internal filters:  Some air compressors will come with an attached refrigerated air dryer.   With these types of air compressors, they will place coalescing filters to remove any residual oil.  These filters should be checked for pressure drop.  If the pressure drop gets too high, then it will rob your compressed air system of air pressure.  Some filters come with a pressure drop indicator which can help you to determine the life of the internal filter element.

6. Unloader valve:  When an air compressor unloads, this valve will help to remove any compressed air that is trapped in the cavity of the air pump.  So, when the air compressor restarts, it does not have to “work” against this “trapped” air pressure.  If they do not fully unload, the air compressor will have to work much harder to restart, wasting energy.

Preventative maintenance is very important, and checks need to be performed periodically.  As for a schedule, I created a rough sequence to verify, change, or clean certain items that are important to your air compressor.  You can also check with your local compressor representative for a more detailed maintenance schedule.

Daily:

  • After stopping, remove any condensate from the receiver tank.
  • Check oil level.

Monthly:

  • Inspect cooling fins on air pump. Clean if necessary
  • Inspect oil cooler. Clean if necessary

Quarterly:

  • Inspect the inlet air filter. Clean or replace if necessary.
  • Check the belt for tension and cracks. Tighten or replace.
  • Check differential pressure indicators on outlet compressed air filters.

Yearly:

  • Replace Air Inlet Filter
  • Replace the air-oil separator
  • Test safety valves and unloader valve
  • Replace compressed air filters
  • Change oil
  • Grease bearings if required

Keeping your air compressor running optimally is very important for pneumatic operations and energy savings.  I shared some important information above to assist.  Another area to check would be your pneumatic system downstream of the air compressor.  EXAIR manufactures engineered products that can reduce air consumption rates.  You can contact an Application Engineer to discuss further on how we can save you energy, money, and your air compressor.

John Ball
Application Engineer
Email: johnball@exair.com
Twitter: @EXAIR_jb

 

Oil And Water Don’t Mix, But Oil And Air Sure Do

Do you have oil in your compressed air system? It may be there on purpose…air operated tools require it, and there are a number of devices on the market that provide a precise amount of oil to keep the moving parts in these tools well lubricated and properly operating.

If it’s not there on purpose, it’s not necessarily a problem, though, and it’s hardly uncommon. Many air compressors are oil lubricated, which means there’s oil being pumped at a constant rate, directly towards the piston rings, and a little bit is always going to end up in the air. As the rings wear, even more makes it past…this is impossible to prevent, but, with proper maintenance, it’s kept to a very minimal amount. There are, of course, oil-less compressor designs, which can eliminate this entirely, but they’ve been known to carry a little heavier price tag. Some situations, though, make them worth every penny.

Trace amounts of oil like this don’t affect a lot of compressed air applications, including the performance of most of our products. There are times, however, when oil needs to be addressed…for instance:

*Blow off prior to painting or coating. Even trace amounts of oil on a surface to be painted can cause big problems.
*Electrical enclosure cooling. Oil won’t affect the heat removal performance of an EXAIR Cabinet Cooler System, but it can indeed cause serious issues with electrical/electronic components and devices if it’s present in the cold air that’s blowing on them.
*Air operated conveyors. Likewise, oil won’t hurt the performance of a Line Vac, but keep in mind that anything in the air supply will get on the material or product you’re conveying.
*Static Eliminators. Here’s a situation where oil in the air WILL have an effect on product performance…the emitter points of your EXAIR Static Eliminator need to be kept clean (including oil free) for proper operation. And, again, anything in your air is going to get onto your product.

This is where proper filtration comes in: properly installed downstream of a Filter Separator, EXAIR’s coalescing Oil Removal Filters take out even trace amounts of oil from the air flow, ensuring your process doesn’t see anything but clean, dry air.

EXAIR Model 9027 Oil Removal Filter, installed between Model 9004 Filter Separator and 9008 Pressure Regulator, using our Modular Coupling Kits
EXAIR Model 9027 Oil Removal Filter, installed between Model 9004 Automatic Drain Filter Separator and 9008 Pressure Regulator, using our Modular Coupling Kits.

Again, oil in your air isn’t always a problem. If you have questions about your application, though, give us a call…if it IS a problem, we’ve got a solution.

Russ Bowman
Application Engineer
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Do you know Where Your Compressor Lives?

To most folks, compressed air is like any other utility. They have no idea where it comes from just that they expect it to be there when they need it. A good exercise is to pay a visit to your compressor room. Breathe in that hot, humid, grimy air. Then think about breathing that day in and day out. That is exactly what your compressor does. And where does all that ingested air go? Throughout your entire compressed air system and into your air tools.

I got a call from a customer complaining that his Air Knife kept plugging up. From the photo to the right you can see that he had horribly bad quality compressed air. The solution was the simple installation of an in-line compressed air filter. EXAIR filters separators remove water, dirt, and rust from the compressed air and prevents contaminants from plugging or damaging compressed air components.

With screw compressors, a thin-film of oil between the rotary vanes provide a seal. Under intense pressure the oil vaporizes. Being in a vapor state, an oil coalescing filter is required in addition to the dirt and water separator. A noteworthy point about compressor oil. It is aggressive and attacks polycarbonate and other materials. Consult your MSDS sheets for compatibility to materials of construction of your air tools.

If you would like assistance from one of our engineers feel welcomed to call 1-800-903-9247

Joe Panfalone
Application Engineer
Phone (513) 671-3322
Fax (513) 671-3363
Web: www.exair.com
Twitter: www.twitter.com/exair_jp
Facebook: http://www.facebook.com/exair