Oil Recovery Rate of Screw Compressor Injection Lubrication: Key Factors Affecting Air Compressor Efficiency

What is oil injection lubrication and oil recovery rate?

In the injection screw compressor, lubricating oil not only bears the functions of lubrication, cooling and sealing, but also participates in the compression process. Oil recovery rate refers to the proportion of lubricating oil effectively captured and returned to lubrication system after compressed air is separated by oil and gas, which is usually expressed as a percentage.

Main Factors affecting oil recovery rate

• air-oil separator performance: the material, structural design and service life of the filter element directly affect the separation efficiency;
• operating conditions: exhaust temperature, pressure fluctuation and load change will change the oil mist particle size and concentration;
• oil return system design: the oil return pipe diameter, slope, orifice size and oil level control accuracy are very important;
• lubricating Oil characteristics: viscosity, volatility and anti-foam affect the aggregation and sedimentation behavior of oil droplets.

Significance of high oil recovery rate to air compressor efficiency

every 1% increase in oil recovery rate can reduce lubricating oil consumption by about 3- 5%, reduce the frequency of oil change and the cost of waste oil treatment; At the same time, avoid the blockage of post-treatment equipment (such as dryers and filters) caused by oil residue, and ensure the long-term stable operation and energy efficiency performance of the system. The oil recovery rate of typical high-efficiency models can reach more.

Schematic diagram of oil-gas separation process

Intake oil mist
Purified air output

Efficient air-oil separator