What is the difference between screw air compressor and scroll air compressor

1, the working principle is different

working principle of scroll air compressor

the main components in the scroll compressor are two involute scroll coils with the same shape but the angular phase position is relatively staggered by 180 °. One is a fixed coil, and the other is driven by an eccentric shaft, and its axis revolves around the axis of the fixed coil.

When the eccentric shaft rotates clockwise, the gas enters the suction cavity from the suction port and is successively ingested into the peripheral crescent-shaped air cavity communicating with the suction cavity. With the closure of these peripheral crescent-shaped air cavities and no longer communicating with the suction cavity, the sealed volume is gradually transferred to the center of the fixed volume and is continuously reduced, and the gas is continuously compressed and the pressure rises.

Working principle of screw air compressor

screw air compressor cylinder is equipped with a pair of intermeshing spiral male and female rotor, the two mutually reverse rotation. The gap between the rotors and between the casing and the rotor is only 5 to 10 wires. The main rotor is driven by the engine or electric motor, and the female rotor is driven by the oil film formed by the main rotor through oil injection, or by the main rotor end and the concave Rotor end synchronous gear drive.

The intake end is supported by a roller bearing, and the exhaust end is supported by an opposed cone roller. Usually, the exhaust end bearing positions the rotor, that is, the thrust bearing, which resists axial thrust and bears radial load. And provide the necessary minimum clearance for axial operation. The working cycle can be divided into three processes: suction, compression and exhaust. As the rotor rotates, each pair of intermeshing teeth successively completes the same duty cycle.

2. Different performance

the scroll air compressor has no reciprocating mechanism, so it has simple structure, small size, light weight, few parts (especially few wearing parts), and high reliability; small torque change, high balance, low vibration, stable operation, and operation Simple and easy to realize automation; it has high efficiency and low noise within its suitable cooling capacity range.

The screw compressor is the same as the piston compressor and belongs to the positive displacement compressor. On the use of the effect to see the screw air compressor has the following advantages. High reliability. Power balance is good. The screw compressor has no unbalanced inertial force, the machine can work smoothly at high speed, and can realize no-foundation operation. It is especially suitable for mobile compressors with small size, light weight and less floor space.

Adaptable. The screw compressor has the characteristics of forced gas transmission, the volume flow is almost not affected by the exhaust pressure, and can maintain high efficiency in a wide range. It is suitable for a variety of working conditions without any change in the structure of the compressor.

Disadvantages of scroll air compressor

1. The surface of the moving parts is mostly curved, and the processing and inspection of these curved surfaces are more complicated, and some require special equipment, so the manufacturing cost is higher.

2. Between the moving parts or between the moving parts and the fixed parts, a certain moving gap is often maintained to achieve sealing. The gas passing through the gap will inevitably cause leakage, which limits the difficulty of the rotary compressor to achieve a larger compression ratio. Therefore, it is mostly used under air-conditioning conditions.

Disadvantages of screw air compressor

1, the rotor tooth surface is a space surface, need to use a special tool, in the expensive equipment processing, the body parts processing accuracy also has higher requirements, must use high precision equipment.

2. Since the volume between the teeth is periodically connected with the suction and exhaust ports, the compressor noise is relatively high.

3. Due to the limitation of rotor stiffness and bearing life, the compressor can only rely on the gap seal, so the screw compressor can only be applied to the medium and low pressure range, and can not be used in high pressure occasions.

4. Due to the large amount of oil injection and the complexity of the oil treatment system, there are many ancillary equipment of the unit.