The difference between oil injection screw air compressor and oil-free screw

The main differences between oil injection screw air compressors and oil-free screw air compressors are reflected in the following aspects:

1. Lubrication method and structural components

1. Oil injection screw air compressors

   • Luction method: lubricate using lubricating oil. During the compression process, lubricating oil is injected into the compression chamber to lubricate, cool and seal.
   • Structural components: including oil and gas cylinder, oil sub-core, minimum pressure valve and other components related to lubricating oil. After the lubricating oil is recycled, it will be separated by an oil and gas separator, and then enters the compression chamber again for lubrication.

2. Oil-free screw air compressor

   • Luction method: lubricate without lubricating oil. It is usually lubricated with water or other oil-free lubricants, or it is relied on the special materials and precision processing of the screw rotor to ensure oil-free operation.
   • Structural components: Since there is no lubricating oil, there are no oil-gas cylinders, oil sub-cores, minimum pressure valves and other components related to lubricating oil. Instead, independent interstage coolers, soda separators, oil mist respirators and other devices are replaced.

2. Compressed air quality

1. Oil injection screw air compressor

   • Air quality: Although it has been treated by an oil and gas separator, a small amount of oil may still remain in the compressed air. This requires further reduction of oil content using an in-line filter.
   • Scope of application: It is suitable for occasions where the quality of compressed air is not particularly high.

2. Oil-free screw air compressor

   • Air quality: The compressed air output is completely oil-free, meeting occasions where compressed air quality requirements are extremely high.
   • Scope of application: Widely used in industries such as food, medicine, electronics, and chemicals that have strict requirements on air quality.

3. Operation and maintenance

1. Fuel injection screw air compressor

   • Operation stability: Due to the cooling and lubricating effect of lubricating oil, the operation of the oil injection screw air compressor is relatively stable, and the components are worn less.
   • Maintenance cost: It requires regular replacement of lubricant and filters, and the maintenance cost is relatively high.

2. Oil-free screw air compressor

   • Operation stability: Oil-free operation is ensured through special materials and precision processing, and the operation stability is equally excellent.
   • Maintenance cost: Since there is no lubricant use, there is no need to change the lubricant and filter regularly, and the maintenance cost is relatively low. However, it is necessary to pay attention to regular inspection and replacement of the air filter and screw rotor.

IV. Energy efficiency and environmental protection

1. Fuel injection screw air compressor

   • Energy efficiency: Due to the cooling effect of lubricating oil, the energy efficiency of the oil injection screw air compressor is relatively high.
   • Environmental protection: Although lubricating oil will be separated after recycling, the treatment of waste oil may still have a certain impact on the environment.

2. Oilless screw air compressor

   • Energy efficiency: With the continuous advancement of technology, the energy efficiency of oilless screw air compressors is also constantly improving, gradually narrowing the gap with oil injection screw air compressors.
   • Environmental protection: The completely oil-free design avoids the pollution of lubricating oil to the environment and is more environmentally friendly.

5. Price and Application

1. Fuel injection screw air compressor

   • Price: Due to the mature technology and the large production scale, the price of oil injection screw air compressor is relatively low.
   • Application: It is widely used in various industrial fields and is the most common type of screw air compressor on the market.

2. Oil-free screw air compressor

   • Price: Due to the complex technology and small production scale, the price of oil-free screw air compressor is relatively high.
   • Application: It is mainly used in occasions where compressed air quality is extremely high, such as food, medicine, electronics, chemicals and other industries.

Summary

The oil injection screw air compressor and oil-free screw air compressor have their own advantages and disadvantages. Which type is chosen depends on the specific application and requirements. In occasions where the quality of compressed air is not particularly high, an oil injection screw air compressor is an economical and practical choice; in occasions where the quality of compressed air is extremely high, such as food, medicine, electronics, chemicals and other industries, an oil-free screw air compressor is a better choice.