Patent ID: 6070421
Filing Date: 2000-06-06
Classification: F04D,F25B

Abstract:
A refrigerating system comprising:condenser;an evaporator; anda two stage centrifugal compressor assembly with a built-in electrical motor between the compressor stages;the electrical motor provided with a cooling system with gas coolant feed and discharge ducts connected to the interior cavity of the motor housing;the condenser inlet connected to the compressor assembly outlet, and the condenser outlet connected by one line to the evaporator inlet via the first choke element;wherein, by the second line to the motor's cooling system via the second choke element the evaporator outlet communicates with the compressor inlet, and the gas coolant discharge duct is connected to the inlet of the compressor assembly's second stage;a third choke element,a separator vessel,a recuperative heat exchanger, andwherein the motor's cooling system is provided with a cooling skirt that is insulated from internal cavity of the motor housing, the cavity of which is located between the stator and the housing and is connected to the second coolant feed and discharge ducts;wherein the third choke element, which is a heat-regulating valve controlled by the coolant temperature and pressure at its inlet, andthe separator vessel mounted in series in the line connecting the condenser outlet to the evaporator, before the first choke element;wherein the separator vessel is connected to the coolant feed duct by the gas phase;wherein the recuperative heat exchanger is connected by the coolant to the line connecting the evaporator outlet to the compressor inlet and to the line connecting the condenser outlet to the evaporator inlet, after the separator vessel; andwherein the second line from the condenser is connected to the second separator vessel and the third choke element is located in the second line and is a heat-regulating valve controlled by the pressure and temperature of the coolant in the second coolant discharge duct.