At present, screw air compressors and piston air compressors are the most widely used in terms of market applications. The mainstream is still screw air compressors, but piston air compressors have not been completely eliminated. The reason The application effect of piston air compressor is better in many environments. Today we will talk about the advantages and disadvantages of piston air compressor.
【advantage】
(1) Regardless of the flow rate, the required pressure can be obtained. The exhaust pressure range is wide, and the maximum pressure can reach 320MPa (industrial applications) or even 700MPa (in the laboratory).
(2) The single machine capacity is any flow below 500m3/min.
(3) In the general pressure range, the requirements for materials are low, and ordinary steel materials are mostly used.
(4) The thermal efficiency is relatively high. Generally, the adiabatic efficiency of large and medium-sized units can reach about 0.7~0.85.
(5) When the air volume is adjusted, the exhaust volume is almost not affected by the fluctuation of the exhaust pressure.
(6) The weight and characteristics of the gas have little effect on the performance of the compressor, and the same compressor can be used for different gases.
(7) The driving machine is relatively simple, most of which use electric motors, and generally do not adjust the speed.
Because of the above advantages, piston compressors are widely used in industry, but this model also has some disadvantages:
[Disadvantages]
(1) The structure is complex and heavy, with many wearing parts, large area, high investment, large maintenance workload and short service life, but it can reach more than 8,000 hours after hard work.
(2) The speed is not high, the machine is large and heavy, and the air displacement of a single machine is generally less than 500m3/min
(3) Vibration occurs during machine operation.
(4) The exhaust is discontinuous and the airflow is pulsating, which is easy to cause pipeline vibration. In severe cases, the pipe network or mechanical parts are often damaged due to airflow pulsation and resonance.
(5) The flow adjustment adopts auxiliary volume or bypass valve. Although simple, convenient and reliable, the power loss is large, and the efficiency is reduced during partial load operation.
(6) For compressors lubricated with oil, the oil in the gas needs to be removed.
(7) When multiple compressor units are used in large factories, there are more operators or greater work intensity.
【Scope of application】
According to the characteristics of the piston compressor, it can be seen that its scope of application is mainly high pressure, medium and small flow. According to the use occasion of the compressor, consider factors such as convenient operation and maintenance, power balance, compact structure, and convenient installation.
The dynamic balance compressor is an opposed compressor in which the piston moves symmetrically. It has the advantages of a general horizontal compressor, but avoids the disadvantages of the general horizontal compressor. It is the development of the horizontal compressor. The cylinders are arranged horizontally and distributed on both sides of the crankcase. The centerline of the cylinder is perpendicular to the centerline of the crankshaft. Each two adjacent rows has a pair of crankshafts with an offset of 180o, and the pistons move relative to each other. The power balance performance of this type of compressor is particularly good. The first and second order inertial forces can be completely balanced, the moment of inertia is also very small, and the speed can be increased by 1 to 1.5 times compared with the horizontal type. The general unit can reach 300 to 400 rpm. Therefore, the compressor and the motor can be reduced by about 50-60% in terms of mass and dimensions. Because the pistons are opposed to each other, the forces of the pistons in the two rows are opposite, which can cancel each other, reducing the load of the main bearing and improving the wear of the bearing. The maximum load on the piston working surface and the stress and moment acting on the components are reduced. The size and weight of the compressor are greatly reduced. The serialization and deformation of this type of air compressor are relatively convenient, so in the large, medium and small compression range, both at home and abroad have achieved great development, and replaced the general horizontal and large vertical compressors with overwhelming advantages.