Tube for heat exchanger

Abstract

A cylindrical member of a tube for a heat exchanger is made of a pair of flat plate portions, and a pair of curved portions for connecting the pair of flat plate portions to each other. One of the pair of curved portions constructs a bonded portion in which an outer wall portion and an inner wall portion are bonded to each by brazing in a state where the outer wall portion and the inner wall portion overlap each other. The inner wall portion has a portion opposite to the outer wall portion put into close contact with the outer wall portion and is bonded to the one flat plate portion in a state where a tip end portion of the inner wall portion opposite to the one flat plate portion is separated from the one flat plate portion.

1 . A tube for a heat exchanger, comprising
 a cylindrical member in which a heat exchange medium flows and which is made of a plate-shaped part having a flow passage section formed in a flat shape, the flow passage section being orthogonal to a direction in which the heat exchange medium flows, wherein   the cylindrical member includes a pair of flat plate portions opposite to each other in parallel in a minor radius direction of the flow passage section, and a pair of curved portions opposite to each other in a major radius direction of the flow passage section and for connecting the pair of flat plate portions to each other,   one curved portion of the pair of curved portions constructs a bonded portion in which an outer wall portion, which extends from an end portion of one flat plate portion in the pair of flat plate portions and constructs an outer wall of the cylindrical member, and an inner wall portion, which extends from an end portion of other flat plate portion in the pair of flat plate portions and constructs an inner wall of the cylindrical member, are bonded by brazing to each other in a state where the outer wall portion and the inner wall portion overlap with each other,   the inner wall portion has an opposite portion opposite to the outer wall portion put into close contact with the outer wall portion, and is bonded to the one flat plate portion in a state where a tip end portion of the inner wall portion opposite to the one flat plate portion is separated from the one flat plate portion, and   the inner wall portion has an extended portion extended from a boundary between the first flat plate portion and the outer wall portion, to a side of the other curved portion, and the tip end portion separated from the one flat plate portion is positioned inside of the boundary in the major radius direction and is opposite to the one flat portion.   
     
     
         2 . The tube for a heat exchanger according to  claim 1 , wherein each of the pair of curved portions is curved in a shape of an arc. 
     
     
         3 . The tube for a heat exchanger according to  claim 1 , wherein
 the inner wall portion has a continuously curved face opposite to the outer wall portion, and   the outer wall portion is extended along and bonded to the continuously curved face of the inner wall portion.   
     
     
         4 . The tube for a heat exchanger according to  claim 1 , wherein
 the extended portion has a wavy-shaped portion that is opposite to the pair of flat plate portions and is formed in a wavy shape in such a way that the wavy-shaped portion functions as an inner fin, and further has a portion opposite to an inner wall face of the other curved portion extended along and put into close contact with the inner wall face of the other curved portion, and   the extended portion is bonded to the flat plate portion in a state where the tip end portion opposite to the flat plate portion on a side of the other curved portion is separated from the flat plate portion.   
     
     
         5 . The tube for a heat exchanger according to  claim 1 , wherein
 a face opposite to the flat plate portion in the extended portion is constructed of a bonded face portion bonded to a flat face of the flat plate portion and a separated face portion separated from the flat plate portion at the tip end portion.   
     
     
         6 . The tube for a heat exchanger according to  claim 1 , wherein
 the inner wall portion has a contact face contacting the outer wall portion, and   the contact face of the inner wall portion has a shape along the outer wall portion.   
     
     
         7 . The tube for a heat exchanger according to  claim 1 , wherein
 the extended portion of the inner wall portion has a contact face contacting a flat shape of the one flat plate portion.