The difference between oil injection screw air compressor and dry screw

The difference between the oil injection screw air compressor and the dry screw air compressor is mainly reflected in the following aspects:

lubrication method:

the oil-injected screw air compressor will inject lubricating oil through a special system during the compression process and mix with the compressed gas to achieve the purpose of lubricating the screw and reducing wear. This method can extend the service life of the machine, but it may cause oil in the compressed air.

The dry screw air compressor does not use lubricating oil, and its screw surface adopts special material and surface treatment method, so no additional lubrication system is required. This makes the compressed air more dry and pure, and is suitable for occasions with high air quality requirements.

Cooling method:

the oil-injected screw air compressor is usually equipped with a cooling system to reduce the temperature of the compressed gas by forced circulation of water to ensure that the gas temperature is within the allowable range.

Dry screw air compressors also use a cooling system, but the focus is on air cooling or other cooling methods that do not require lubricating oil to discharge the heat generated during the compression process.

Application occasions:

oil-injected screw air compressor is suitable for occasions where the gas contains oil or the gas is compatible with the lubricating oil, such as air compression, refrigeration and gas compression in the process. Its exhaust pressure is generally in the range of 0.8MPa ~ 4.5MPa.

Dry screw air compressor is more suitable for the need for dry, pure compressed air occasions, such as food, medical and other industries. Due to its high exhaust temperature, the single-stage pressure ratio is generally small (1.5~3.5), so it is often used for low-pressure, large-flow air compression requirements.

Maintenance and use costs:

oil-injected screw air compressors require regular replacement of lubricating oil and may incur additional maintenance costs due to mixing of oil and gas.

Dry screw air compressors reduce oil-related maintenance costs because they do not require lubricating oil, but may increase other maintenance costs due to high speeds and high requirements for bearings and shaft seals.

In summary, there are significant differences between the oil-injected screw air compressor and the dry screw air compressor in terms of lubrication, cooling, application, and maintenance and use costs. The choice of which type of air compressor depends on the specific use needs and environmental conditions.