The difference between scroll compressor and screw compressor

There are significant differences between scroll compressors and screw compressors in many aspects. These differences are mainly reflected in the working principle, structural characteristics, performance performance, applicable scenarios, and maintenance requirements. The following is a detailed explanation of the difference between the two:

1. working principle

• scroll Compressor: Scroll compressor is a positive displacement compression compressor. Its working principle is to use the relative revolution of the movable scroll and the fixed scroll to form a continuous change of the closed volume, so as to achieve the purpose of compressing gas. With the rotation of the orbiting scroll, the enclosed volume is gradually reduced, and the gas is compressed and discharged.
• Screw compressor: Screw compressor is a volumetric compressor, which relies on the rotation of the screw in the cylinder to cause the volume change of the spiral tooth space to complete the gas compression process. The screw compressor is mainly composed of a pair of male and female rotors meshing with each other. With the rotation of the rotor, the volume of the tooth groove changes continuously, so as to realize the suction, compression and discharge of gas.
• The water-lubricated screw compressor of Shanghai Granklin Group adopts the structure of single screw and two star wheels, and water is used as lubricant in the compression chamber.

2. structure characteristics

• scroll Compressor: The structure of the scroll compressor is relatively simple, mainly composed of movable scroll, fixed scroll, body, anti-rotation ring and eccentric shaft. The movable scroll and the fixed scroll are staggered by 180 ° and meshed with each other to form a plurality of crescent-shaped working volumes.
• Screw compressor: The structure of the screw compressor is slightly complicated, mainly composed of rotor, casing, bearing, shaft seal, balance piston and air delivery adjustment device. The male and female rotors are placed in parallel and mesh with each other to form a plurality of closed cogging volumes.

3. performance

• volumetric efficiency and pressure ratio: The scroll compressor can still maintain a high volumetric efficiency under high pressure ratio conditions, because it uses flexible seals to prevent leakage and small leakage. The screw compressor has low volumetric efficiency and large leakage under high pressure ratio conditions.
• Lubrication system screw compressors are highly dependent on lubricating oil and require a complex oil system to ensure lubrication and sealing effects. The lubrication system of the scroll compressor is relatively simple, and the temperature requirement of the lubricating oil is also low.
• Noise and vibration: The noise and vibration level of the scroll compressor is low, because its suction, compression and exhaust process are carried out simultaneously and continuously, and the pressure rise speed is slow. Although the power balance performance of screw compressor is good, the noise and vibration level is relatively high.

4. applicable scenarios

• scroll Compressor: Due to its high efficiency, low noise, small size and other advantages, scroll compressors are widely used in air conditioning, refrigeration, general gas compression, automobile engine superchargers and vacuum pumps. However, its application range is limited by power, and is currently mainly used in air conditioners with a power of 1 to 15kW.
• Screw compressor: Screw compressors are widely used in industrial production because of their simple structure, reliable operation and convenient maintenance. Especially in the need for large flow, high pressure, screw compressor has obvious advantages.

5. Maintenance Requirements

• scroll Compressor: The scroll compressor is a fully enclosed structure and is relatively simple to maintain. Generally speaking, it is only necessary to check and replace the filter screen, oil and filter element regularly.
• Screw compressor after the screw compressor has been running for a period of time (such as about 10000 hours), the oil system needs to be overhauled and lubricating oil added. In addition, it is necessary to regularly check and replace the wearing parts to ensure the normal operation of the equipment.

In summary, there are significant differences between scroll compressors and screw compressors in terms of working principles, structural characteristics, performance, applicable scenarios, and maintenance requirements. When choosing a compressor type, it should be considered comprehensively according to the specific application scenarios and needs.