Multistage air supplementing screw compressor with economizer loop

Abstract

The invention discloses a multistage air supplementing screw compressor with an economizer loop. More than two compression stages are executed on a pair of male and female rotors, wherein each mutually separated compression stage is provided with at least two air supplementing ports at different positions; the air supplementing ports at different positions are located at the same air supplementingpressure or different air supplementing pressure positions, and at least two air supplementing ports at different compression stages are located at different air supplementing pressure positions respectively. When the compression ratio is greater than a first preset numerical value, the air supplementing loops of the first compression stage and the second compression stage are opened; when the compression ratio is greater than the second preset value and less than the first preset value, the air supplementing loop of the first compression stage is opened; when the compression ratio is less than a second preset numerical value, the air supplementing loop of the first compression stage is opened or closed. The screw compressor can adapt to further improvement of capacity and energy efficiency under the large-pressure-ratio working condition, the exhaust temperature of the screw compressor can be reduced, the operation range of the compressor is expanded, and the reliability of the compressor is improved.

Description

technical field [0001] The invention relates to a multi-stage gas-supply screw compressor with an economizer circuit, which belongs to the technical field of industrial refrigeration. Background technique [0002] As is well known, in the fields of low-temperature heat pump unit or food refrigeration and other related industrial refrigeration, the refrigeration cycle unit used includes a screw refrigeration compressor with an economizer, throttling device, heat exchanger and other components Constitute a complete refrigeration unit, wherein, a screw compressor with an economizer, a throttling device and at least two heat exchangers together form a refrigerant cycle system with an economizer, through the compression process of the compressor The economizer air supply port is opened to add an economizer air supply circuit in the refrigeration cycle to improve the unit's capacity and energy efficiency. [0003] During the operation of the core component compressor in the exist...

AI Technical Summary

Problems solved by technology

Therefore, in the existing screw compressors, the improvement of the performance of the screw compressor using the economizer cycle through the economizer air supply is very limited, no matter from the perspective of improving the volumetric efficiency of the compressor or the isentropic compression efficiency. It is necessary to further increase the capacity of the economizer to achieve greater system subcooling to consider the improvement of capacity and energy efficiency, resulting in a large increase in cost

Moreover, under the operating condition of a larger pressure ratio, this kind of refrigerant circulation system with an economizer circulation circuit still faces the risk of high exhaust temperature and high motor temperature due to the large pressure ratio, and it is easy to exceed the operating range limit of the compressor. , and the capacity and energy efficiency of the compressor under the condition of high pressure ratio will be further attenuated with the increase of the compression ratio, making it difficult for the heating or cooling capacity of the unit to meet the design requirements, thus bringing great design challenges to the system design Difficulty and great reliability risk

[0005] In addition, the single-unit two-stage screw compressors that have been launched in the market have been popularized in single-water hot water units. Although the heating performance level is high, there are obvious shortcomings of low capacity and low energy efficiency for occasions with cooling requirements. , so its promotion is greatly restricted

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