Working Principle and Operation Process of Screw Air Compressors

Screw air compressors, as highly efficient and reliable compressed air equipment, play a vital role in modern industrial production. This article explains in detail the working principle and operation process of screw air compressors, helping users better understand and apply this essential technology in various industrial environments.

1. Working Principle of a Screw Air Compressor

A screw air compressor operates based on the interaction of two intermeshing rotors—a male rotor and a female rotor—within a precisely machined housing. The compression process is performed by reducing the volume of trapped air between the rotor lobes and the casing. The working cycle includes the following key stages:

• Intake Phase: As the rotors begin to turn, the cavities between the rotor lobes open to the air inlet. Ambient air is drawn into the compression chamber.

• Sealing Phase: When the rotor lobes move past the inlet port, the air is trapped and sealed within the chamber.

• Compression Phase: Continued rotation reduces the chamber volume, compressing the air. During this stage, lubricating oil is injected to cool, lubricate, and seal the compression chamber.

• Discharge Phase: Once the compressed air reaches the outlet port, it is discharged into the downstream system for use.

This continuous cycle ensures smooth and efficient compression with minimal pulsation.

2. Operation Process: Air Path and Oil Path

Screw air compressors have two main operational circuits: the air circuit and the oil circuit, which work simultaneously to ensure optimal performance.

(1) Air Circuit Process

This process describes the flow of air from intake to delivery:

• Air Filtration: Incoming air passes through a high-efficiency air filter that removes dust and debris, protecting the compressor internals.

• Inlet Valve Control: The filtered air enters through an inlet valve, which adjusts airflow based on demand.

• Compression Unit: Air is compressed by the rotating screws inside the compressor block.

• Oil-Air Separation: The compressed oil-air mixture enters a separator tank, where most of the oil is removed via mechanical separation methods.

• Aftercooler: The clean, compressed air is then cooled by an aftercooler to reduce its temperature before distribution.

(2) Oil Circuit Process

Lubrication oil is crucial for screw compressor efficiency and longevity. The oil circuit follows this flow:

• Oil Tank: Stores lubricating oil and supplies it to the compressor via an oil pump.

• Oil Injection: Oil is sprayed into the compression chamber to cool and seal the air during compression.

• Oil-Air Separation: The oil is separated from the compressed air in the separator tank and collects at the bottom.

• Oil Cooler: The recovered oil is cooled by air or water in an oil cooler to prevent overheating.

• Oil Filter: The cooled oil passes through a filter to remove impurities and maintain oil quality.

• Return Cycle: Clean oil is recirculated back into the compression chamber, repeating the cycle.

3. Key Advantages of Screw Air Compressors

Screw air compressors offer a range of performance and maintenance benefits:

• ✅ High Energy Efficiency: Continuous compression without pressure fluctuations results in lower energy consumption.

• ✅ Exceptional Reliability: Fewer moving parts mean less wear, lower failure rates, and reduced maintenance costs.

• ✅ Smooth & Quiet Operation: Minimal vibration and low noise levels ensure better working conditions.

• ✅ Broad Application Range: Adaptable to various industries and capable of operating under a wide range of pressures and airflows.

Conclusion

The screw air compressor achieves continuous gas compression through a pair of meshing rotors within a sealed housing. Its dual-circuit operation—air compression and oil circulation—ensures efficient performance and long-term reliability. With advantages such as energy savings, durability, low noise, and broad industrial applicability, screw compressors are widely used in manufacturing, automotive, food processing, electronics, and more.

For companies seeking dependable and efficient compressed air solutions, understanding the working principles and operational flow of screw air compressors is key to optimizing performance and reducing operational costs.

Why Choose the Sollant Four-in-One Air Compressor?