The Research On Methods For Improving Compression Performance Of Inverter Compressor

Scroll compressor have advantages of simple structure, small volume, light weight, small vibration, low noise, smoothly suction and exhausting, and flow adjusting convenience etc, it has been widely used in refrigeration, air conditioning, gas units and other fields, and developed from the constant speed scroll compressor into inverter scroll compressor. But the practice showed that the compression performance of inverter scroll compressor at low revolution is poor. The research is based on this question.Firstly, theoretically analyses on the influence of revolution to discharge capacity under one angle, eventual compression, polytropic energy head gained by the effective gas and polytropic efficiency is made. Relation curves of discharge capacity-revolution, eventual compression-revolution, polytropic energy head-revolution and polytropic efficiency-revolution are gained by experimental tests. The study showed that increase of leakage with reducing of revolution was the main factor that made the compression performance poor. So it is very necessary to reduce leakage to improve compression performance. Then, three aspects of the research work based on the leakage problem of inverter scroll compressor were made.Tangential sealing mechanism of the scroll compressor between fixed scroll teeth and orbiting scroll teeth was analyzed in this paper, the root of the tangential leakage of inverter scroll compressor is explored, and a new kind of tangential sealing mechanism is put forward, it is called elastic bushing, this mechanism guarantee that inverter scroll compressor has good sealing performance at low revolution, and also could make the orbiting scroll plate move toward the centre of fixed scroll, so orbiting scroll plate could not be hold up, meanwhile, it could reduce processing and assembling accuracy of orbiting scroll plate and parts combined with the orbiting scroll plate.To enhance the tangential seal performance of scroll compressor, the labyrinth tangential seal structure are put forward and designed. The comprehensive effect of the labyrinth structure is analyzed, according to the flow characteristics of the tangential leakage, calculation formula for tangential leakage of the labyrinth tangential seal structure and that of the structure without labyrinth were given, and the leakages of these two tangential seal structures are calculated. The test bench to determine the leakage of tangential seal structure is designed and built, and tangential leakages of the labyrinth tangential seal structure and that of the structure without labyrinth were determined. By comparing the leakages of these two kinds of tangential seal structure, which were got by theoretical calculation and experimental determination, showed that the algorithms for tangential leakage of the tangential labyrinth seal and that of the structure without labyrinth were accurate, leakages of the two tangential seal structure were increasing with the increasing of the adjoining compression chambers’ pressure difference, the ratios of the leakages of labyrinth tangential seal accounted for those of the structure without labyrinth are fundamentally constant, only58.9%. This showed that the sealing ability of the tangential labyrinth seal is greater than that of the sealing structure without labyrinth.To improve the radial seal performance of scroll compressor, the labyrinth radial seal structure is put forward and designed. The comprehensive effect of the labyrinth structure is analyzed, according to the flow characteristics of the radial leakage, calculation formula for radial leakage of the labyrinth radial seal structure and that of the structure without labyrinth were given, and the leakages of these two radial sealing structure are calculated. The test bench to determine the leakage of radial seal structure are designed and built, and radial leakages of the labyrinth radial seal structure and that of the structure without labyrinth were determined. By comparing the leakages of these two kinds of radial seal structure, which were got by theoretical calculation and experimental determination, showed that the algorithms for radial leakage of the radial labyrinth seal and that of the structure without labyrinth were accurate, leakages of the two radial seal structures were increasing with the increasing of the adjoining compression chambers’pressure difference, the ratios of the leakages of labyrinth radial seal accounted for those of the structure without labyrinth are fundamentally constant, only79%. This showed that the sealing ability of the radial labyrinth seal is greater than that of the sealing structure without labyrinth.The main findings and innovations of this study are as follows, the main root that made the compression performance poor is the increasing of leakage at low revolution. Three methods to improve the compression performance of inverter scroll compressor were put forward. They are elastic bushing institutions, labyrinth tangential seal structure and labyrinth radial seal structure. These innovations have superiority for improving the compression performance, and opened up a vast range of prospects.