Oil Lubricated Air Compressor Technology

Main Parts and Functions of a Rotary Screw Compressor

Rotors

These perform the core duty of rotary screw air compressors and the pair will be housed inside compression cylinders. The turning rotors trap a volume of air and compress it to a higher pressure as it moves through the rotor.

Electric motor

A compressor needs power, this comes from the motor. The motor is used to power the rotation of the male rotor, which subsequently drives the female rotor.

Bearings

These are used to make sure rotors stay securely in the correct position. They are positioned on the ends of both rotors and ensure that the rotors are rotating evenly and remain balanced.

Suction and Discharge Valve

These valves control the initial gas retrieval and removal from the compressor. The suction valve opens to let air into the system and the discharge valve receives the pressurised air at the end of the process.

Oil vs Oil Free

In an oil injected rotary screw compressor, oil is used for four main purposes. It is injected into the compression chamber to cool the machine, provide adequate lubrication of the moving parts, provide sealing and to aid with noise dissipation. The thermostatic valve also plays an integral role in maintaining the optimum temperature over a range of ambient temperatures by controlling the quantity of oil that is circulated to the oil cooler or the bypass.

To remove oil from the final product, the compressed air leaves the airend and is passed through to an oil separator. This will remove the majority of the oil through velocity changes. Coalescent filters can then be used to further reduce the oil quantity, resulting in a low oil carry over of around 2-5 ppm.

An oil free air compressor, on the other hand, does not use any oil in the compression cavities. The male and female rotors do not touch and their positions are maintained through lubricated timing gears that are outside of the compression chamber. This ensures that the air compressor output is completely oil free air. In water-injected oil free compressors, water is used instead of oil to perform the same duties such as cooling and lubrication.

Many businesses will opt for an oil free air compressor compared to oil lubricated compressors as oil-free designs provide guaranteed clean air.
 

Lubricated Compressor Maintenance Tips

Use the correct oil

In injected screw compressors, oil plays an integral role. You should always ensure that you choose an oil that is the correct type for your installation. Genuine OEM oil is always the best choice as it helps to maintain the integrity of your system and keeps your compressor running smoothly and efficiently.

Check for oil and air leaks

Leaks in your system can drastically decrease efficiency and ultimately cost you money. Leak detection surveys can be carried out by expert aftermarket engineers who use ultrasonic leak detection technology to quickly and easily identify leaks in the system.

Regularly inspect the airend

Your airend should generally last around 44,000 hours if maintained correctly. Factors such as overheating, poor lubrication, condensation and corrosion can cause damage to the airend which may result in malfunction or breakdown. Regularly checking for any issues with the airend can help you to diagnose and fix a problem early on.

Check hoses regularly

Check your compressors hoses periodically to ensure they are not cracked or corroded, this could result in a leak which may reduce energy efficiency and ultimately cost you money.

Drain condensation from air receiver tanks

Regularly draining your receiver tanks will keep it clean and running smoothly. A build-up of moisture could be detrimental to your compressed air output.

Check and change air filters

If your air filter is not performing effectively, it may be allowing dirt and dust particles from the outside in. This will force your compressor to work harder to intake air. If you notice a build-up of dust, you may want to consider replacing your air filter.