| 摘要 |
PROBLEM TO BE SOLVED: To provide a refrigerating device having a two-stage screw compressor (hereinafter called compressor) having a discharge gas temperature lower than an allowable upper limit temperature, and capable of improving performance. SOLUTION: This refrigerating device includes a refrigerant circuit configured by successively annularly connecting the compressor 1, an oil separator 2, a condenser 3, a supercooler 5 for cooling a refrigerant, an expansion valve 6 and an evaporator 7 by refrigerant pipes, an oil returning pipe conduit for returning a lubricant from the oil separator 2 to the compressor 1 through an oil cooler 9, a liquid refrigerant injection pipe conduit having an electronic expansion valve 13 for returning the liquid refrigerant from the condenser to an intermediate pressure chamber of the compressor 1 through the oil cooler 9 and controlling a flow rate of a liquid refrigerant for cooling the lubricant in the oil cooler 9, and a temperature sensor 14 detecting a temperature of a discharge-side refrigerant gas of the compressor 1. A microcomputer 12 controls opening/closing of the electronic expansion valve 13 so that an output of the temperature sensor 14 is kept at the predetermined allowable upper limit temperature and near the upper limit temperature over a range of operable condition. COPYRIGHT: (C)2011,JPO&INPIT |
