At present, screw air compressors and piston air compressors are the most widely used in terms of applications in the market. The mainstream is still screw air compressors, but piston air compressors have not been completely eliminated. The reason In many environments, the application effect of piston air compressors is better. Today we will talk about the advantages and disadvantages of piston air compressors.
【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 application) 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 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 discharge volume is hardly affected by the fluctuation of the discharge pressure.
(6) The weight and characteristics of the gas have little effect on the working performance of the compressor, and the same compressor can be used for different gases.
(7) The driving machine is relatively simple, and most of them use electric motors, generally without speed regulation.
Due to the above advantages, piston compressors are widely used in industry, but this model also has some disadvantages:
【shortcoming】
(1) The structure is complex and heavy, with many wearing parts, large floor space, high investment, large maintenance workload, and short service life, but it can reach more than 8,000 hours after hard work.
(2) The rotation speed is not high, the machine is large and heavy, and the exhaust volume of a single machine is generally less than 500m3/min
(3) There is vibration in the operation of the machine.
(4) The exhaust is discontinuous and the airflow is pulsating, which is easy to cause the pipeline to vibrate. In severe cases, the pipeline network or parts are damaged due to the airflow pulsation and resonance.
(5) The flow regulation adopts auxiliary volume or bypass valve. Although it is 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 many operators or more 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, small and medium flow. According to the application of the compressor, factors such as convenient operation and maintenance, dynamic balance, compact structure, and convenient installation are considered.
The dynamic balance type compressor is an opposed type compressor with symmetrical movement of the piston. It has the advantages of the general horizontal compressor, but avoids the shortcomings 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 center line of the cylinder is perpendicular to the center line of the crankshaft. Every two adjacent rows has a pair of cranks with a staggered angle of 180°, and the pistons move relative to each other. The dynamic balance performance of this type of compressor is particularly good, its first and second order inertial forces can be completely balanced, the inertia moment is also small, the speed can be increased by 1~1.5 times compared with the horizontal type, and the general unit can reach 300~400rpm. Therefore, compressors and motors can be reduced by approximately 50-60% in terms of mass and external dimensions. Due to the opposite movement of the pistons, the opposing forces of the two rows of pistons can cancel each other out, which reduces the load of the main bearing and improves the wear of the bearing. The size and weight of the compressor are greatly reduced. The serialization and deformation of this type of air compressor are more convenient, so in the large, medium and small compression range, both at home and abroad have achieved great development, replacing the general horizontal and large vertical compressor units with overwhelming advantages.