Refrigeration system and its pressure balance control device

Abstract

A refrigeration system with pressure balancing function includes a condensing unit, a first refrigerant delivery pipeline, and a pressure balance control device including a temperature control unit, a first refrigerant control valve and a refrigerant supply switching controller. The temperature control unit determines if the temperature of the evaporator is abnormal, generates a temperature adjustment trigger signal that shifts between adjustment level and non-adjustment level. The refrigerant supply switching controller will determine, based on the level of the temperature adjustment trigger signal, whether to output the valve-open signal to the first refrigerant control valve. When the temperature adjustment trigger signal received by the refrigerant supply switching controller is at the adjustment level, the refrigerant supply switching controller will not output the valve-open signal to the first refrigerant control valve, so that the first refrigerant control valve is closed to stop delivering the refrigerant to the first refrigerant delivery pipeline.

We claim: 
     
         1 . A refrigeration system with pressure balancing function, comprising:
 a condensing unit, to supply a liquid refrigerant;   a first refrigerant delivery pipeline, to receive refrigerant from the condensing unit and deliver the refrigerant to an evaporator, for conversion from liquid state to gaseous state inside the evaporator;   a pressure balance control device, comprising:
 a temperature control unit, to judge if the temperature of the evaporator is abnormal or not, and to generate a temperature adjustment trigger signal; said temperature adjustment trigger signal shifts between an adjustment level and a non-adjustment level, 
   a first refrigerant control valve, configured on the first refrigerant delivery pipeline; depending on reception of a valve-open signal or not, it determines whether or not to deliver the refrigerant from the condensing unit to the first refrigerant delivery pipeline; and
 a refrigerant supply switching controller, electrically connected to the temperature control unit and the first refrigerant control valve, to receive temperature adjustment trigger signal from the temperature control unit; based on the level of the temperature adjustment trigger signal, it determines whether or not to output the valve-open signal to the first refrigerant control valve; 
   when the temperature control unit judges that the evaporator has an abnormal temperature and the temperature adjustment trigger signal received by the refrigerant supply switching controller is at the adjustment level, the refrigerant supply switching controller will not output the valve-open signal to the first refrigerant control valve, so that the first refrigerant control valve is closed to stop the refrigerant from the condensing unit from entering the first refrigerant delivery pipeline.   
     
     
         2 . The system defined in  claim 1 , wherein said temperature control unit of the pressure balance control device comprises:
 a temperature detector, to detect the temperature of the evaporator;   a temperature controller, to generate the valve-open signal and a heat control signal depending on the temperature of the evaporator and a preset temperature;   an electric heater, to supply or stop supplying electrical heat energy to the evaporator depending on the level of the temperature adjustment trigger signal; when the temperature adjustment trigger signal is at the adjustment level, the electric heater supplies electrical heat energy, and when the temperature adjustment triggering level is at the non-adjustment level, the electric heater stops supplying electrical heat energy; and   a thermal switch, electrically connected to the temperature controller, the electric heater and the refrigerant supply switching controller; based on control by the heat control signal of the temperature controller, it generates the temperature adjustment trigger signal either at the adjustment level or at the non-adjustment level.   
     
     
         3 . The system defined in  claim 1 , wherein said refrigerant supply switching controller of the pressure balance control device comprises:
 a first selector switch, having:
 a first contact, electrically connected to the first refrigerant control valve, to output the valve-open signal; 
 a second contact, to receive the valve-open signal; 
 a third contact; 
 a control contact, electrically connected to the temperature control unit to receive the temperature adjustment trigger signal, and depending on the level of the temperature adjustment trigger signal, to selectively establish electrical connection between the second contact and either the first contact or the third contact, so that the valve-open signal can be transferred through the second contact to either the first contact or the third contact. 
   
     
     
         4 . The system defined in  claim 1 , wherein said first refrigerant delivery pipeline is to deliver the refrigerant of a first flow from the condensing unit, and the refrigeration system also comprises:
 a second refrigerant delivery pipeline, to deliver the refrigerant of a second flow from the condensing unit to the evaporator, and the second flow is smaller than the first flow;   the pressure balance control device includes:
 a second refrigerant control valve, configured inside the second refrigerant delivery pipeline, which, based on reception of the valve-open signal or not, determines whether or not to deliver the refrigerant from the condensing unit to the second refrigerant delivery pipeline; and 
 a pressure control unit, electrically connected to the second selector switch of the refrigerant supply switching controller, to judge if the pressure of the condensing unit is abnormal and accordingly generate a pressure triggering signal and send it to the second selector switch of the refrigerant supply switching controller; the pressure triggering signal shifts between an overpressure level and a non-overpressure level; 
   when the pressure control unit judges that the pressure of the condensing unit is abnormal, and the pressure triggering signal received by the second selector switch of the refrigerant supply switching controller is at the overpressure level, the second selector switch of the refrigerant supply switching controller will not output the valve-open signal to the first refrigerant control valve, but output the valve-open signal to the second refrigerant control valve, so that the second refrigerant control valve will open to deliver the refrigerant of the second flow to the second refrigerant delivery pipeline.   
     
     
         5 . The system defined in  claim 4 , wherein the pressure control unit of the pressure balance control device comprises:
 a pressure detector, to detect the pressure of the refrigerant inside the condensing unit, and generate a detected pressure value, and   a pressure-controlled switch, electrically connected to the pressure detector and the refrigerant supply switching controller, to determine the level of the pressure triggering signal based on the detected pressure value of the pressure detector;   when the detected pressure value received by the pressure-controlled switch reaches an upper limit, the pressure-controlled switch will output the pressure triggering signal at the overpressure level;   when the detected pressure value received by the pressure-controlled switch reaches a lower limit value, the pressure-controlled switch will output the pressure triggering signal at the non-overpressure level.   
     
     
         6 . The system defined in  claim 4 , wherein the refrigerant supply switching controller of the pressure balance control device comprises:
 a first selector switch, having:
 a first contact, electrically connected to the first and the second refrigerant control valves; 
 a second contact to receive the valve-open signal; 
 a fourth contact to output the valve-open signal; and 
   a second selector switch, having:
 a fifth contact, electrically connected to the fourth contact of the first selector switch to receive the valve-open signal; 
 a sixth contact, electrically connected to the first refrigerant control valve, to output the valve-open signal to the first refrigerant control valve when electrically connected to the fifth contact; 
 a seventh contact, electrically connected to the second refrigerant control valve, to output the valve-open signal to the second refrigerant control valve when electrically connected to the fifth contact; 
 a control contact, electrically connected to the pressure control unit, to selectively establish electrical connection between the fifth contact and either the sixth contact or the seventh contact based on the level of the pressure triggering signal, so that the valve-open signal is delivered through the fifth contact to either the sixth contact or the seventh contact. 
   
     
     
         7 . A pressure balance control device, suitable for mounting in a refrigeration system; the refrigeration system comprises a condensing unit to supply liquid refrigerant, a first refrigerant delivery pipeline to receive the refrigerant from the condensing unit and deliver the refrigerant to the evaporator that converts the liquid state to the gaseous state; the pressure balance control device comprises:
 a temperature control unit, to judge if the temperature of the evaporator is abnormal or not, and to determine whether or not to generate a temperature adjustment trigger signal; the temperature adjustment trigger signal shifts between an adjustment level and a non-adjustment level;   a first refrigerant control valve, configured inside the first refrigerant delivery pipeline, to determine, based on reception of a valve-open signal, whether or not to deliver the refrigerant from the condensing unit to the first refrigerant delivery pipeline; and   a refrigerant supply switching controller, electrically connected to the temperature control unit and the first refrigerant control valve, to receive the temperature adjustment trigger signal from the temperature control unit, and to determine, based on the level of the temperature adjustment trigger signal, whether or not to output the valve-open signal to the first refrigerant control valve;   when the temperature control unit judges that the temperature of the evaporator is abnormal and the temperature adjustment trigger signal received by the refrigerant supply switching controller is at the adjustment level, the refrigerant supply switching controller will not output the valve-open signal to the first refrigerant control valve, so that the first refrigerant control valve is closed to stop delivering the refrigerant from the condensing unit to the first refrigerant delivery pipeline.   
     
     
         8 . The device defined in  claim 7 , wherein the temperature control unit includes:
 a temperature detector, to detect the temperature of the evaporator;   a temperature controller, to generate the valve-open signal and a heat control signal based on the temperature of the evaporator and a preset temperature;   an electric heater, to supply or stop supplying electrical heat energy to the evaporator depending on the level of the temperature adjustment trigger signal; when the temperature adjustment trigger signal is at the adjustment level, the electric heater supplies electrical heat energy, and when the temperature adjustment triggering level is at the non-adjustment level, the electric heater stops supplying electrical heat energy, and   a thermal switch, electrically connected to the temperature controller, the electric heater and the refrigerant supply switching controller; based on control by the heat control signal of the temperature controller, it generates the temperature adjustment trigger signal either at the adjustment level or at the non-adjustment level.   
     
     
         9 . The device defined in  claim 7 , wherein said refrigerant supply switching controller includes:
 a first selector switch, having:
 a first contact, electrically connected to the first refrigerant control valve, to output the valve-open signal; 
 a second contact to receive the valve-open signal; 
 a third contact; 
 a control contact, electrically connected to the temperature control unit, to receive the temperature adjustment trigger signal, to selectively establish electrical connection between the second contact and either the first contact or the third contact based on the level of the temperature adjustment trigger signal, so that the valve-open signal is delivered through the second contact to either the first contact or the third contact. 
   
     
     
         10 . The device defined in  claim 7 , wherein said refrigeration system also includes a second refrigerant delivery pipeline to deliver the refrigerant from the condensing unit to the evaporator; the first refrigerant delivery pipeline of the refrigeration system is to deliver the refrigerant of a first flow, while the second refrigerant delivery pipeline is to deliver the refrigerant of a second flow; the second flow is smaller than the first flow; the pressure balance control device also comprises:
 a second refrigerant control valve, configured inside the second refrigerant delivery pipeline, to determine, depending on reception of the valve-open signal or not, whether or not to deliver the refrigerant from the condensing unit to the second refrigerant delivery pipeline; and   a pressure control unit, electrically connected to the refrigerant supply switching controller, to judge if the pressure of the condensing unit is abnormal or not and to accordingly generate a pressure triggering signal and send it to the refrigerant supply switching controller; the pressure triggering signal shifts between an overpressure level and a non-overpressure level;   when the pressure control unit judges that the pressure of the condensing unit is abnormal and the pressure triggering signal received by the refrigerant supply switching controller is at the overpressure level, the refrigerant supply switching controller will not output the valve-open signal to the first refrigerant control valve, but output the valve-open signal to the second refrigerant control valve, so that the second refrigerant control valve will open to deliver the refrigerant of the second flow to the second refrigerant delivery pipeline.   
     
     
         11 . The device defined in  claim 10 , wherein said pressure control unit includes:
 a pressure detector, to detect the pressure of the refrigerant inside the condensing unit, and to generate a detected pressure value; and   a pressure-controlled switch, electrically connected to the pressure detector and the refrigerant supply switching controller, to determine the level of the pressure triggering signal based on the detected pressure value of the pressure detector;   when the detected pressure value received by the pressure-controlled switch reaches an upper limit, the pressure-controlled switch outputs the pressure triggering signal at the overpressure level;   when the detected pressure value received by the pressure-controlled switch reaches a lower limit value, the pressure-controlled switch outputs the pressure triggering signal at the non-overpressure level.   
     
     
         12 . The device defined in  claim 10 , wherein said refrigerant supply switching controller includes:
 a first selector switch, having:
 a first contact, electrically connected to the first and the second refrigerant control valve; 
 a second contact to receive the valve-open signal; 
 a fourth contact to output the valve-open signal; and 
   a second selector switch, having:
 a fifth contact, electrically connected to the fourth contact of the first selector switch to receive the valve-open signal; 
 a sixth contact, electrically connected to the first refrigerant control valve, to output the valve-open signal to the first refrigerant control valve when electrically connected to the fifth contact; 
 a seventh contact, electrically connected to the second refrigerant control valve, to output the valve-open signal to the second refrigerant control valve when electrically connected to the fifth contact; 
 a control contact, electrically connected to the pressure control unit, to selectively establish electrical connection between the fifth contact and either the sixth contact or the seventh contact based on the level of the pressure triggering signal, so that the valve-open signal is delivered through the fifth contact to either the sixth contact or the seventh contact.