What is the difference between oil-free, micro-oil and oil-injected screw air compressors

The difference between oil-free, micro-oil, and oil-injected screw air compressors is mainly in the lubrication method, compressed air quality and application field.

Lubrication method:

oil-free screw air compressor: no lubricating oil is used in the compression process. It is lubricated and cooled by pure water, so there is no oil in the compression chamber. This type of machine requires the use of a special water-lubricated screw rotor, which has special requirements for the screw, and generally requires special coating treatment or stainless steel to prevent corrosion.

Micro-oil screw air compressor: the oil content is below 3ppm, usually called micro-oil screw air compressor. It uses a high-performance oil and gas separator to reduce the oil content in the compressed air, so that the quality of the discharged compressed air is higher.

Oil injection screw air compressor: also known as "oil injection" screw air compressor, need to add special screw oil to lubricate, cool and seal the screw. This model will produce oil-containing compressed air during the compression process, so it is necessary to be equipped with an efficient oil and gas separation device to reduce the oil content in the compressed air.

Compressed air quality:

oil-free screw air compressor: The compressed air provided is completely oil-free, suitable for applications with extremely high air quality requirements, such as pharmaceuticals, food processing, precision manufacturing, etc.

Micro-oil screw air compressor: The compressed air provided has extremely low oil content and meets the needs of most industrial applications.

Oil-injected screw air compressor: Although the oil content can be reduced by the oil and gas separation device, the oil content in the compressed air is higher than that of the oil-free and micro-oil models.

Application areas:

oil-free screw air compressor: mainly used in industries with high air quality requirements, such as medicine, food, precision manufacturing, etc.

Micro-oil screw air compressor: widely used in general machinery, metallurgy, electric power, chemical and other industrial fields.

Oil injection screw air compressor: usually used in mining, metallurgy, electric power, chemical and other industries in the air quality requirements are relatively low.

In summary, the difference between oil-free, micro-oil, and oil-injected screw air compressors is mainly in the lubrication method, compressed air quality and application field. When choosing a suitable screw air compressor, it needs to be considered according to the actual application requirements.