The purity of compressed air depends on 3 basic air compressor filters. This article will introduce the functions, working principles and maintenance of these air compressor filters.
Air compressor air filter
Uses of air compressor air filter
The air compressor air filter is an important protective barrier for the air compressor. Air compressor air filter can also be called air intake filter, which usually use high-precision filter papers and fine fiber layers as materials.
(Air compressor air filter)
The ambient air contains a lot of moisture, dust particles, oil mist and other impurities. When these impurities enter the compressed air system, they will cause pipeline corrosion and blockage, leading to failures of instruments and pneumatic equipment. The cleaner the inhaled air, the more guaranteed the service life of the oil filter, oil-gas separation core and oil.
After using the air compressor air filter, impurities in the air can be effectively removed, so that the air inhaled is clean, outside impurities are prevented from entering the air end, and the equipment can operate safely.
Because the compressor air end are very precise, for example the clearance between rotors of rotary screw air compressor is 50-200µm, thus outside impurities entering will inevitably cause damage to the air end, causing the air compressor air end to get stuck or even scrapped.
Air filter replacement standards
The replacement cycle of the air compressor air filter is determined by its design service life and the air quality of the air compressor environment. Therefore, there are two types of replacement cycles for the air compressor air filter:
Replace after the actual use time reaches the design life time. The design service life of the air compressor air filter is usually 2000 hours, and it should be replaced after expiration.
If the actual air quality is good, it can also be extended according to the actual condition of the filter element, but the maximum extension time is no more than 1000 hours.
The use time of the air compressor air filter with poor environmental conditions should be shortened. Replace it immediately after the blockage alarm within the design service life.
The pressure difference alarm setting value caused by the blockage of the air compressor air filter is usually 0.05bar.
The hazards of overdue use of air compressor air filter
The volume of air compressor unit will be insufficient, affecting production;
The filter element pressure resistance is too large, the air compressor unit load increases, and the life of the air end is reduced;
The actual compression ratio of the air compressor unit increases, the load of the air end increases, and the life of the air end is reduced;
The damage of the air compressor air filter causes outside impurities to enter the air end, causing the air end to get stuck or even scrapped;
Air compressor Oil filter
Importance of air compressor oil filter
Most positive displacement air compressors rely on lubricating oil to perform high-efficiency operations. The function of air compressor oil filter is to filter out metal particles, impurities, and colloids and other impurities generated during the operation of the air compressor.
If the oil containing impurities is directly sent to the surface of the moving parts, it will not only accelerate the wear of the parts, but also cause the blockage of the oil circuit.
Therefore, oil filter is necessary for oil lubricated air compressors to purify the circulating oil, and ensure good lubrication of the friction surface and extend the service life of the air compressor.
Material of oil filter: high-precision filter paper. Usually the oil filter is an external screw-in type, and some air compressor models also use built-in oil filters.
Replacement standard of oil filter
Replace after the actual use time reaches the design life time. The design service life of the oil filter is usually 2000 hours, and it must be replaced after expiration.
The use time of air compressor oil filter with poor environmental conditions should be shortened. Replace immediately after the blockage alarm within the design service life, and the oil filter blockage alarm setting value is usually 1.0 – 1.4bar.
The hazards of overdue use of oil filter
Insufficient oil return after blockage leads to excessive exhaust temperature, shortening the service life of lubricating oil and the air oil separator element.
Insufficient oil return after blockage leads to insufficient lubrication of the air end, which seriously shortens the service life of the air end.
After the filter element is damaged, unfiltered oil containing a large amount of metal particles enters the air end, causing damage to the air end.
Air compressor air oil separator element
Importance of air compressor air oil filter
The air compressor air oil separator element, also known as air oil filter, oil gas separator element, which is mainly used to separate compressed air and oil. It is a key component that determines the quality of compressed air in air compressors.
High-quality air oil filters can not only ensure the high efficiency of the compressor, but also extend the service life of the filter element to thousands of hours.
(Air oil separator element)
Material of air oil separator element
The element of air oil separator is composed of multiple tightly fitted ultra-fine fiber layers, a metal support layer, and a gravity sedimentation layer.
Working principle of air compressor air oil separator element
The ultra-fine fiber layers are made of multi-layers of fine glass fibers, which intercept and aggregate the fine oil particles and oil mist in the compressed air, so that they are concentrated at the bottom of the air oil filter and returned to the compressor lubrication system through the oil return pipe.
(Working principle of air oil filter)
Replacement standard of air oil filter
(1) Replace after the actual use time reaches the design life time. The service life of the air oil filter is usually 4000-8000 hours, and it must be replaced after expiration.
(2) Replace the air oil filter immediately after the blockage alarm sounds within the designed service life. The blockage alarm setting value of the air oil separator element is usually 0.8-1.0 bar.
Hazards of overuse of the air oil filter
-
- Poor air oil filterseparation efficiency leads to high oil content in compressed air, affecting the operation of the downstream precision air filters,air dryers, gas-using equipment, especially when there is no air compressor tank installed;
- The pressure resistance increases after blockage of air compressor air-oil separator, resulting in decrease of exhaust pressure and an increase in the energy consumption of the air compressor unit;
- After failure, the glass fiber filter separation material falls off and enters the oil, resulting in damage and abnormal wear of the air end.
Maintenance of air compressor filters
Daily maintenance has a great impact on the service life and maintenance cost of the air compressor. The following matters should be paid attention to when maintaining air compressor filters.
Maintenance of air compressor air filter
Air compressor air filter is the first barrier for preventing impurities enter air compressor. If the air filter is clogged or damaged, particles larger than 200µm will enter the compressor compression chamber and bearing chamber, which will not only greatly shorten the service life of the oil filter and air oil separator element, but also reducing the compression efficiency, and accelerating the wear of the bearing.
- Clean air filter regularly: Remove the filter regularly for cleaning according to usage. Use a soft brush to gently brush away dust and dirt on the surface, and be careful not to damage the filter material.
- Replace air filter element: The filter element is the core component of the air filter and needs to be replaced regularly. Generally speaking, when the air filter is obviously blocked or damaged, it should be replaced with a new one in time.
- Pay attention to the use environment: Try to avoid using the air compressor in harsh environments, such as places with a lot of dust and high humidity. Because thatcan increase the workload of air compressor air filter and shorten its service life.
Maintenance of air compressor oil filter
The oil filter should be replaced after the first 500 hours of operation of a new air compressor. Disconnect the power supply of the air compressor to ensure that it will not start midway. Remove the oil filter with a special wrench, screw the new oil filter back to the oil filter seat with wrench or hands, and tighten it hard to ensure sealing.
It is recommended to replace air compressor oil filter every 1500-2000 hours of use. The replacement cycle should be shortened when used in harsh environments.
It is strictly forbidden to use the oil filter element beyond the expiration date. Otherwise, due to serious clogging of the filter element, the pressure difference exceeds the tolerance limit of the bypass valve, the bypass valve automatically opens, and a large amount of dirt and particles will directly enter the compressor air end, causing serious consequences.
The replacement of diesel portable air compressor oil filter and diesel motor filter should follow the maintenance requirements of the diesel engine, and the replacement method is similar to that of the screw air compressor oil filter.
(KDP series diesel portable air compressor in oil&gas industry)
Maintenance of air compressor air oil separator element
Under normal operation, the service life of air oil separator element is about 3000 hours, but the quality of lubricating oil and the filtration accuracy of air have a huge impact on its life.
In harsh use environments, the maintenance and replacement cycle of air oil filter must be shortened, a pre air filter should be considered when the air compressor working environment is very awful.
The air oil filter must be replaced after it expires or the pressure difference between the front and rear exceeds 0.12Mpa. Otherwise, the motor will be overloaded, the oil content in the compressed air will increase, and the exhaust pressure will drop.
Replacement steps:
Remove the control pipe joints installed on the air oil separator cover.
Remove the fastening bolts of the air oil separator cover and remove the air oil separator cover.
Take out the old air compressor air-oil filter.
Remove the asbestos pad and dirt stuck to the edge of the upper cover for sealing.
Install the new air oil separator element.
Reinstall the upper cover, return oil pipe, and control pipes as they were.
Start the air compressor and check for air leaks.
Air compressor filters FAQ
Air compressor not giving enough air pressure
Failure description
When the motor is running and the air compressor is charging the air tank, the air pressure indicated by the pressure gauge does not reach expected pressure value.
Causes of failure
- The pressure gauge fails.
- The transmission belt between the air compressor and the engine is too loose and slips, or the pipeline between the air compressor and the air tank is broken or the joint is leaking.
- The air oil separator, pipeline or air filter is blocked due to excessive sediment.
- The exhaust valve of the air compressor is not sealed tightly, the spring is too soft or broken, the bolts of the cylinder head of the air compressor are loose, the sand holes and the cylinder head gasket are damaged and leak.
- The shaft seal, piston and piston ring of the air compressor are worn too much and leak.
Troubleshooting
- Observe the pressure gauge. If the indicated pressure is insufficient, let the motor run at for several minutes. If the pressure still does not rise or rises slowly, and when pushed down the emergency stop button, the deflation sound is very strong, indicating that the pressure gauge is damaged. Repair or replace the pressure gauge.
- If there is no deflation sound or the deflation sound is very small in the above test, check whether the belt of the air compressor is too loose, and whether there are loose, broken or leaking parts from the air compressor to the air tank, to the air inlet pipe of the control valve, and the joint.
- Check whether the air oil separator and the air filter and the pipeline are blocked by too much dirt. If it is blocked, the dirt should be removed.
- Check whether the cylinder liner and piston ring of the air compressor are excessively worn.
- After the above inspection, if the cause of the fault cannot be found, further check whether the exhaust valve of the air compressor is leaking, whether the spring is too soft or broken, and whether the liner is damaged. Replace or repair the damaged parts according to the fault found.
How to maintain the air compressor daily
Air compressors require regular maintenance in daily use:
- Check the oil level, exhaust temperature and exhaust pressure every day, and check for any abnormal sounds.
- Regularly replace the oil filter element, oil separator filter element, air intake filter element and lubricating oil.
- Regularly check the air intake control valve, minimum pressure valve, electric control box connecting wire terminals, safety valve, and cooling fan.
What type of oil to use for air compressor？
Special lubricating oil for air compressor (semi-synthetic oil, fully synthetic oil).
Advantages:
(1) Excellent anti-oxidation and thermal stability.
(2) Excellent high-temperature lubricity, reducing the wear of the air compressor.
(3) Excellent heat dissipation effect, effectively reducing the high temperature generated during the operation of the air compressor.
(4) Excellent anti-rust and sealing properties.
(5) Excellent anti-emulsification properties.
Explore Kotech’s air compressors
From air compressor selection to installation to maintenance, we can provide a complete guide including optimal advice and solutions for your project.
Now our website has opened a new function named “bookcase“. In the future, the updates of the Kotech’s products will be shown to this bookcase in a timely manner.
Click below to know more about the air compressors we manufactured.
