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.
- After stopping, remove any condensate from the receiver tank.
- Check oil level.
- Inspect cooling fins on air pump. Clean if necessary
- Inspect oil cooler. Clean if necessary
- 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.
- 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.
Compressor internals image courtesy of h080, Creative Commons License.
Image Courtesy of Ron Mullan, Tinker AFB