Difference between oil-injected, micro-oil and oil-free compressors

Oil-injected, micro-oil, and oil-free compressors are significantly different in many aspects. These differences are mainly reflected in the lubrication method, compressed air quality, application field and equipment characteristics. The following is a detailed comparative analysis:

1. lubrication method

• oil-injected compressor: Lubricate, cool and seal the screw by injecting special screw oil into the compressor. This lubrication method helps to reduce the friction between the screws, improve mechanical efficiency, and ensure the stable operation of the equipment. However, this also makes it inevitable that a certain amount of oil is contained in the compressed air.
• Micro-oil compressor: Although lubricating oil is also used, its oil content is very low, usually below 3ppm. The micro-oil compressor uses a high-performance oil-gas separator to reduce the oil content in the compressed air and ensure a higher quality of the compressed air.
• Oil-free compressor: No lubricating oil is used at all during the compression process. It is usually lubricated and cooled by pure water or other oil-free media, so there is no oil in the compression chamber. This type of screw has special requirements, such as special coating treatment or stainless steel to prevent corrosion.

2. compressed air quality

• oil-injected compressor: Although equipped with an efficient oil and gas separation device, the compressed air may still contain a certain amount of oil. In order to remove this part of the oil, it is usually necessary to install a precision filter on the gas line.
• Micro-oil compressor: The compressed air provided has extremely low oil content, which meets the air quality requirements of most industrial applications.
• Oil-free compressor: The compressed air provided is completely oil-free and is suitable for applications with extremely high air quality requirements, such as pharmaceuticals, food processing, precision manufacturing, etc.

3. Application Areas

• oil-injected compressor: Because of its stable performance, high efficiency and wide application range, it is usually used in mining, metallurgy, electric power, chemical and other industries where the air quality requirements are relatively low.
• Micro-oil compressor: It is widely used in general machinery, metallurgy, electric power, chemical and other industrial fields, and it is also suitable for some occasions that have certain requirements for air quality.
• Oil-free compressor: Mainly used in industries with extremely high air quality requirements, such as medicine, food, precision manufacturing, etc. In these industries, any trace of oil can contaminate the product or affect product quality.

4. device characteristics

• oil-injected compressor: Compact structure, stable performance, low vibration and noise. At the same time, due to the assistance of lubricating oil, the internal male and female rotor clearance can be accurately controlled, reducing the backflow and leakage of compressed air.
• Micro-oil compressor: It also has the characteristics of high efficiency, energy saving, compact and convenient, stable and reliable. A small amount of lubricating oil not only reduces the friction and wear between the screws, but also extends the service life of the equipment and reduces maintenance costs.
• Oil-free compressor: The body is compact in design and easy to maintain. Since lubricating oil is not used, equipment failure and product contamination caused by lubricating oil contamination are avoided. At the same time, the cylinder liner of the oil-free compressor adopts advanced surface hardening technology and noise reduction design, which further improves the durability and quietness of the equipment.

In summary, oil-injected, micro-oil, and oil-free compressors have significant differences in lubrication methods, compressed air quality, application areas, and equipment characteristics. When choosing a suitable compressor, it is necessary to consider comprehensively according to the actual application requirements.