Lubrication plays an important role in boosting the efficiency and longevity of any piece of machinery (especially rotating equipment). A screw air compressor is no different, and it requires lubrication to be in top working condition. In this article, Parth Trivedi of Atlas Copco talks about why your screw compressor needs Oil and why they don’t!
If you are an owner of a screw air compressor, here is everything you need to know about the screw air compressor oil (for the record, an exclusive oil is used for screw air compressors differ from motor oil and other common oil). An oil-injected screw compressor requires oil for several key functions:
- Cooling
Oil helps dissipate heat generated during compression, preventing overheating. If the temperature of the compressor is too high, the element or all rotating parts would be excessively stressed, and the service life would be shortened. - Lubrication
Oil prevents friction and wear on moving parts, especially the rotors. Metal-to-metal contact could lead to operational issues and early breakdown. - Sealing
Oil creates an effective seal between rotors and housing for efficient compression. - Cleaning and filtration
Oil traps contaminants and impurities from incoming air to protect internal components. - Noise reduction
Oil can reduce compressor noise by acting as a sound barrier.
For all its benefits, it must be noted that the use of generic lubricants and irregular maintenance will negatively affect the machine’s lifetime, overall performance and energy efficiency.
So, when do I need to change my screw compressor oil?
To determine when your screw compressor oil needs replacing, several factors need to be taken into account:
- Operating hours
The number of hours the compressor has been running - Oil type
Different oils have varying lifespans - Compressor load
Higher loads may require more frequent oil changes. - Oil filtration
Is the oil filtration system working effectively to maintain oil quality? - Environmental conditions
Harsh operating environments like high temperature, dust and humidity may require more frequent oil changes.
You should always check your maintenance history and service manual for the manufacturer’s recommendations before working on a compressor.
The role of a 100% oil-free compressor
Apart from the above, nowadays, industries are moving towards 100% oil-free compressors (Class 0), which do not allow oil to mix with air during the compression process and make use of only a small amount of oil for the lubrication of gears.
As a result of no entry of oil in screw element, its temperature rises to above 150°C when compressing air up to 2.0 or 2.2 bar g, as a result it’s needs to be cooled with the help of an intercooler before it enters the second stage for reaching the final desired pressure. Due to the limited use of oil in 100% oil-free compressors, their life can reach up to 16000 running hours, while in the case of oil-lubricated compressors, the life generally extends to around 4000 running hours. You should always consult the manufacturer for any query.
