Falling film evaporator

Abstract

A falling film evaporator includes a heat transfer tube group with heat transfer tubes extending longitudinally, a tank having a refrigerant flow inlet, a liquid refrigerant distribution part, a vapor outlet pipe extending out from a lateral or upper position of the tank other than a top of the tank as viewed along a longitudinal direction of the tank, and an isolation member covering a place below a lowest portion of a connection portion of the tank and the vapor outlet pipe as viewed along an axial direction of the heat transfer tubes. Liquid refrigerant supplied through the refrigerant flow inlet falls downwardly onto the heat transfer tube group. The isolation member extends between the vapor outlet pipe and the liquid refrigerant distribution part to allow refrigerant to pass through an upper portion. A longitudinal direction of the isolation member is the same as the heat transfer tubes.

1 . A falling film evaporator used for a refrigeration apparatus, the falling film evaporator comprising:
 a heat transfer tube group having a plurality of heat transfer tubes, the heat transfer tubes having heat medium flowing therein and extending longitudinally;   a tank having the heat transfer tube group disposed therein and being provided with a refrigerant flow inlet;   a liquid refrigerant distribution part arranged to allow liquid refrigerant of refrigerant in a gas-liquid two-phase state supplied into the tank through the refrigerant flow inlet to downwardly fall onto the heat transfer tube group;   a vapor outlet pipe extending out from a lateral or upper position of the tank other than a top of the tank as viewed along a longitudinal direction of the tank; and   an isolation member covering a place below a lowest portion of a connection portion of the tank and the vapor outlet pipe as viewed along an axial direction of the heat transfer tubes, the isolation member extending between the vapor outlet pipe and the liquid refrigerant distribution part and being arranged to allow refrigerant to pass through an upper portion,   the isolation member being provided such that a longitudinal direction of the isolation member is the same as a longitudinal direction of the heat transfer tubes.   
     
     
         2 . The falling film evaporator according to  claim 1 , wherein
 the isolation member extends to an inner surface of the tank above the vapor outlet pipe as viewed along the axial direction of the heat transfer tubes and has an upper opening through an upper portion of the isolation member in a thickness direction thereof; or   the isolation member extends beyond an upper side of the vapor outlet pipe as viewed along a direction in which the vapor outlet pipe extends out from the tank, and extends short of a portion of an inner surface of the tank above the vapor outlet pipe to form an upper gap.   
     
     
         3 . The falling film evaporator according to  claim 2 , wherein
 the plurality of upper openings or the plurality of upper gaps are separately provided such that the upper openings or the upper gaps closer to the vapor outlet pipe have larger passage resistances to refrigerant passing through the upper openings or the upper gaps.   
     
     
         4 . The falling film evaporator according to  claim 2 , wherein
 the upper opening or the upper gap is provided at a position higher than the connection portion of the vapor outlet pipe and the tank.   
     
     
         5 . The falling film evaporator according to  claim 2 , wherein
 an oil return opening is formed in a lower end of the isolation member, or an oil return gap is formed between a lower end of the isolation member and the inner surface of the tank; and   the oil return opening and the oil return gap are smaller than the upper opening or the upper gap.   
     
     
         6 . The falling film evaporator according to  claim 1 , wherein
 a longitudinal end portion of the isolation member is connected to an inner wall of the tank.   
     
     
         7 . The falling film evaporator according to  claim 3 , wherein
 the upper opening or the upper gap is provided at a position higher than the connection portion of the vapor outlet pipe and the tank.   
     
     
         8 . The falling film evaporator according to  claim 3 , wherein
 an oil return opening is formed in a lower end of the isolation member, or an oil return gap is formed between a lower end of the isolation member and the inner surface of the tank; and   the oil return opening and the oil return gap are smaller than the upper opening or the upper gap.   
     
     
         9 . The falling film evaporator according to  claim 8 , wherein
 a longitudinal end portion of the isolation member is connected to an inner wall of the tank.   
     
     
         10 . The falling film evaporator according to  claim 3 , wherein
 a longitudinal end portion of the isolation member is connected to an inner wall of the tank.   
     
     
         11 . The falling film evaporator according to  claim 4 , wherein
 an oil return opening is formed in a lower end of the isolation member, or an oil return gap is formed between a lower end of the isolation member and the inner surface of the tank; and   the oil return opening and the oil return gap are smaller than the upper opening or the upper gap.   
     
     
         12 . The falling film evaporator according to  claim 11 , wherein
 a longitudinal end portion of the isolation member is connected to an inner wall of the tank.   
     
     
         13 . The falling film evaporator according to  claim 4 , wherein
 a longitudinal end portion of the isolation member is connected to an inner wall of the tank.   
     
     
         14 . The falling film evaporator according to  claim 5 , wherein
 a longitudinal end portion of the isolation member is connected to an inner wall of the tank.   
     
     
         15 . The falling film evaporator according to  claim 2 , wherein
 a longitudinal end portion of the isolation member is connected to an inner wall of the tank.