Difference between screw compressor and scroll compressor

Screw compressors and scroll compressors are two common displacement compressors. They have significant differences in structure, working principles, performance characteristics and application scenarios. The following are the specific differences between the two:

1. Design principles and structure

• screw compressor：
  • structure: It consists of a pair of meshed helical male and female rotors (twin screws) or a main screw and two star wheels (single screw). The rotors rotate in reverse in the casing.
  • working principle: Through periodic changes in the rotor tooth space volume, gas suction, compression and discharge are realized. The gaps between the rotors and between the rotor and the casing form a compression chamber, and the gas is compressed in the compression chamber and discharged.
• scroll compressor：
  • structure: It consists of a moving scroll disk and a fixed scroll disk. The spiral lines of the moving disk and the fixed disk are 180° out of phase, forming multiple closed crescent spaces.
  • working principle: Moving around the center of the static plate revolves around, and the volume of the enclosed space gradually shrinks. After being compressed, the gas is discharged through the center hole of the static plate.

2. Performance characteristics comparison

3. application scenarios

• screw compressor：
  • air compression: Provides high-pressure airflow for pneumatic tools and equipment.
  • gas treatment: Compression of inert gases such as hydrogen and helium.
  • industrial production: Drive cylinders to perform industrial operating tasks.
  • medical care: Medical equipment such as ventilators and hemodialysis machines.
  • military space: Propellant pressure supply and stable internal air pressure of the spacecraft.
• scroll compressor：
  • precision air conditioning: Low noise and low vibration characteristics are suitable for high-end air conditioning equipment.
  • medical equipment: Such as portable oxygen concentrators, micro pumps, etc.
  • household appliances: Small refrigeration equipment, micro compressor applications.
  • new energy vehicles: Heat pump air conditioning system to improve energy efficiency.

4. Core advantages and limitations

• screw compressor：
  • advantages: Forced gas transmission characteristics (exhaust volume is less affected by pressure), multiphase mixing transmission capacity (can contain liquid gas, dust gas).
  • limited: Not suitable for high-pressure scenarios (usually ≤3MPa), miniaturization is difficult.
• scroll compressor：
  • advantages: Smooth operation, low noise, suitable for high-precision equipment.
  • limited: The compression ratio is limited (usually ≤10), the sealing requirements are high, and the scroll diameter needs to be increased when the flow rate is large, resulting in an increase in volume.

summary

Screw compressors are suitable for industrial scenarios with wide flow ranges and high pressure stability requirements, while scroll compressors have unique advantages in pursuing precision equipment with low noise and high efficiency. The selection requires comprehensive consideration based on specific needs (such as pressure range, flow requirements, noise limits) and cost budget.