Heat exchanger and air conditioner provided with heat exchanger

Abstract

A heat exchanger provided with a plurality of plate-like fins 2 arranged in parallel with a predetermined interval and a plurality of flat-shaped heat transfer pipes 3 inserted in a direction orthogonal to said plate-like fins 2 and through which a refrigerant flows, in which said heat transfer pipe 3 has an outside shape with a flat outer face arranged along an air flow direction and a section substantially in an oval shape and first and second refrigerant flow passages 31 a, 31 b made of two symmetric and substantially D-shaped through holes having a bulkhead 32 between the two passages inside, which is bonded to said plate-like fin 2 by expanding diameters of said first and second refrigerant flow passages 31 a, 31 b by a pipe-expanding burette ball.

1 . A heat exchanger provided with a plurality of plate-like fins arranged in parallel with a predetermined interval and a plurality of flat-shaped heat transfer pipes inserted in a direction orthogonal to said plate-like fins and through which a refrigerant flows, wherein
 said heat transfer pipes have an outside shape with a flat outer face arranged along an air flow direction and a section substantially in an oval shape and first and second refrigerant flow passages made of two symmetric and substantially D-shaped through holes having a bulkhead between the two passages inside, which are bonded to said plate-like fin by expanding diameters of said first and second refrigerant flow passages by a pipe-expanding burette ball.   
     
     
         2 . The heat exchanger according to  claim 1 , wherein a flow passage of one of or both of said first and second refrigerant flow passages has a plurality of protruding strips extending in an axial direction on an inner wall face. 
     
     
         3 . The heat exchanger according to  claim 2 , wherein
 said plurality of protruding strips are formed at a required height so that their distal ends are brought into contact with a circular outer circumferential face of the pipe-expanding burette ball.   
     
     
         4 . The heat exchanger according to  claim 2 , wherein a height of the protruding strip after pipe expansion is approximately 0.1 to 0.3 mm. 
     
     
         5 . A heat exchanger provided with a plurality of plate-like fins arranged in parallel with a predetermined interval and a plurality of flat-shaped heat transfer pipes inserted in a direction orthogonal to said plate-like fins and through which a refrigerant flows, wherein
 said heat transfer pipes have an outside shape with a flat outer face arranged along an air flow direction and a section substantially in an oval shape and first and second refrigerant flow passages made of two symmetric and substantially D-shaped through holes having a bulkhead between the two passages inside, and one of or both of said first and second refrigerant flow passages have a plurality of protruding strips extending in an axial direction on an inner wall face of the flow passage.   
     
     
         6 . The heat exchanger according to  claim 5 , wherein
 said refrigerant flow passage on which said plurality of protruding strips are provided is constituted so that a distance between a predetermined point at the center part of said refrigerant flow passage and each of distal end portions of said plurality of protruding strips in the section becomes substantially equal.   
     
     
         7 . The heat exchanger according to  claim 5 , wherein
 a plurality of refrigerant circuits are constituted in a column direction using said heat transfer pipe whose intermediate portion is given bending work, and refrigerant outlet portions of said first and second refrigerant flow passages of one of adjacent heat transfer pipes and refrigerant inlet portions of said first and second refrigerant flow passages of the other heat transfer pipe are connected to each other by two return bend pipes in a cross state.   
     
     
         8 . The heat exchanger according to  claim 5 , wherein a plurality of refrigerant circuits are constituted in a column direction using said heat transfer pipe whose intermediate portion is given bending work, and refrigerant outlet portions of said first and second refrigerant flow passages of one of adjacent heat transfer pipes and refrigerant inlet portions of said first and second refrigerant flow passages of the other heat transfer pipe are connected to each other by a single return bend pipe so that the refrigerants are mixed. 
     
     
         9 . An air conditioner provided with a refrigerating cycle in which a compressor, a condenser, a throttle device, and an evaporator are sequentially connected by piping, wherein
 a refrigerant is used as an operating fluid and the heat exchanger according to  claim 1  is used as said evaporator or condenser.   
     
     
         10 . The air conditioner according to  claim 9 , wherein any of a HC single refrigerant or a mixed refrigerant containing HC, R32, R410A, R407C, carbon dioxide is used as a refrigerant. 
     
     
         11 . The heat exchanger according to  claim 3 , wherein a height of the protruding strip after pipe expansion is approximately 0.1 to 0.3 mm. 
     
     
         12 . The heat exchanger according to  claim 6 , wherein
 a plurality of refrigerant circuits are constituted in a column direction using said heat transfer pipe whose intermediate portion is given bending work, and refrigerant outlet portions of said first and second refrigerant flow passages of one of adjacent heat transfer pipes and refrigerant inlet portions of said first and second refrigerant flow passages of the other heat transfer pipe are connected to each other by two return bend pipes in a cross state.   
     
     
         13 . The heat exchanger according to  claim 6 , wherein
 a plurality of refrigerant circuits are constituted in a column direction using said heat transfer pipe whose intermediate portion is given bending work, and refrigerant outlet portions of said first and second refrigerant flow passages of one of adjacent heat transfer pipes and refrigerant inlet portions of said first and second refrigerant flow passages of the other heat transfer pipe are connected to each other by a single return bend pipe so that the refrigerants are mixed.   
     
     
         14 . An air conditioner provided with a refrigerating cycle in which a compressor, a condenser, a throttle device, and an evaporator are sequentially connected by piping, wherein
 a refrigerant is used as an operating fluid and the heat exchanger according to  claim 5  is used as said evaporator or condenser.   
     
     
         15 . The air conditioner according to  claim 14 , wherein
 any of a HC single refrigerant or a mixed refrigerant containing HC, R32, R410A, R407C, carbon dioxide is used as a refrigerant.