Centrifugal refrigerator

Abstract

The invention aims to provide a centrifugal refrigerator having high pressure head specification. The centrifugal refrigerator can avoid surge, and the capacity of the refrigerator can be reduced to the load capacity on the equipment side during low pressure head. The centrifugal refrigerator comprises a measuring unit, an economizer steam valve (7) and a control device (20), wherein the measuring unit is used for measuring the pressure difference between a condenser (4) and an evaporator (5); the economizer steam valve (7) is arranged on a flow path (11) and used for opening and closing the flow path (11), and the flow path (11) is used for communicating an economizer (6) with the middle part of multiple compression stages of a multi-stage centrifugal compressor (TC); the control device (20) controls the opening of a guide vane which is used for adjusting the flow of suction facing the multi-stage centrifugal compressor (TC), and controls the lower limit of opening of the guide vane variably on the basis of the relationship between the preset pressure difference of the condenser (4) and the evaporator (5) and the lower limit of opening of the guide vane according to the pressure difference measured by the measuring unit.

Description

Technical field [0001] The present invention relates to a centrifugal refrigerator, and more particularly, to a centrifugal refrigerator with a high-pressure head specification that can avoid surging and ensure an operating area at a low head (head) and at a partial load. Background technique [0002] Conventionally, centrifugal refrigerators used in refrigeration and air-conditioning apparatuses are composed of a closed system in which refrigerant is enclosed, and are composed of an evaporator that takes heat from a fluid to be cooled to evaporate the refrigerant and exerts a cooling effect. A compressor that compresses the refrigerant gas evaporated by the evaporator to make it a high-pressure refrigerant gas, a condenser that cools and condenses the high-pressure refrigerant gas with a cooling fluid, and performs the condensation of the above-mentioned condensed refrigerant. An expansion valve (expansion mechanism) that decompresses and expands is connected by a refrigerant pi...

AI Technical Summary

Problems solved by technology

[0011] In addition, when restarting the refrigerator, since the pressure head is generally small at startup, the IGV is gradually opened to control so that no sudden load is applied to the sliding parts such as the bearings and gears of the compressor. When the state of the head is restarted, there is a problem that surge occurs when the IGV keeps the low opening degree.

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