Refrigeration system

Abstract

A refrigerating system comprises a compressor, a condenser, an expansion valve, an evaporator, sensors for detecting respectively a temperature and a pressure of a refrigerant sucked into the compressor, and a pressure of a refrigerant discharged from the compressor, a liquid injection system including an injection passage and a flow control valve connected in the injection passage, and a control means for estimating a temperature of gas refrigerant discharged from the compressor, from detected values delivered from the sensors, and for delivering an instruction for controlling the injection quantity of the liquid refrigerant, depending upon the estimated temperature, to the flow regulating valve, thereby it is possible to control a temperature of the discharged gas from the compressor to a set value, irrespective of an operating condition.

1 . A refrigerating system comprising: 
 a compressor sucking thereinto a refrigerant, for compressing the refrigerant,    a condenser for condensing the refrigerant discharged from the compressor,    a liquid injection means for injecting a liquid refrigerant into the compressor,    sensors for respectively detecting a temperature and a pressure of the refrigerant sucked into the compressor, and a pressure of the refrigerant discharged from the compressor,    a control means for controlling an injection quantity of the liquid refrigerant injected into the compressor, depending upon detected values delivered from the sensors, wherein the control means estimates a temperature of a gas refrigerant discharged from the compressor from the detected values delivered from the sensors, and delivers an instruction for controlling the injection quantity of the liquid refrigerant, depending upon the estimated temperature, to the liquid injection means.    
   
   
       2 . A refrigerating system comprising: 
 a compressor sucking thereinto a refrigerant, for compressing the refrigerant,    a condenser for condensing the refrigerant discharged from the compressor,    a depressurizing means for depressurizing the condensed refrigerant,    an evaporator for evaporating the depressurized refrigerant,    a liquid injection means for injecting a liquid refrigerant into the compressor,    sensors for respectively detecting a temperature and a pressure of the refrigerant sucked into the compressor, and a pressure of the refrigerant discharged from the compressor,    a control means for controlling an injection quantity of the liquid refrigerant injected into the compressor, wherein the control means estimates a temperature of the refrigerant discharged from the compressor, from detected values delivered from the sensors, and delivers an instruction for controlling the injection quantity of the liquid refrigerant, depending upon the estimated temperature, to the liquid injection means.    
   
   
       3 . A refrigerating system as set forth in  claim 1 , wherein the control means comprises a means for comparing the estimated temperature and a set temperature with each other, and a computing means for computing an injection quantity of the liquid refrigerant from the estimated temperature if the estimated temperature is higher than the set temperature.  
   
   
       4 . A refrigerating system as set forth in  claim 2 , wherein the liquid injection means comprises an injection passage through which the liquid refrigerant flows, and a flow adjusting means connected in the injection passage, for changing the injection quantity of the liquid refrigerant, depending upon the instruction delivered from the control part.  
   
   
       5 . A refrigerant system as set forth in  claim 1 , wherein an additional temperature sensor for detecting a temperature of a gas refrigerant discharged from the compressor is provided, and the control means controls the injection quantity of the liquid refrigerant, depending upon the detected value by the temperature sensor if a deviation between a detected value by the second temperature sensor and the estimated temperature is lower than a set value, but the control means controls the injection quantity of the liquid refrigerant, depending upon the estimated temperature, if the deviation is not less than the set value.