Heat exchanger and method of making it

Abstract

A heat exchanger is constructed by tubes, corrugated fins and head pipes, which are assembled together. Herein, the tube is constructed by bending a flat plate whose surfaces are clad with brazing material to form a first wall and a second wall, which are arranged opposite to each other with a prescribed interval of distance therebetween to provide a refrigerant passage. Before bending, a number of swelling portions are formed to swell from an interior surface of the flat plate by press. By bending, the swelling portions are correspondingly paired in elevation between the first and second walls, so their top portions are brought into contact with each other to form columns each having a prescribed sectional shape corresponding to an elliptical shape or an elongated circular shape each defined by a short length and a long length. The columns are arranged to align long lengths thereof in a length direction of the tube corresponding to a refrigerant flow direction such that obliquely adjacent columns, which are arranged adjacent to each other obliquely with respect to the length direction of the tube, are arranged at different locations and are partly overlapped with each other with long lengths thereof in view of a width direction perpendicular to the length direction of the tube. The tubes, corrugated fins and head pipes are assembled together and are then placed into a heating furnace to heat for a prescribed time.

What is claimed is:  
     
         1 . A heat exchanger comprising: 
 a flat tube constructed by a first wall and a second wall which are arranged opposite and apart in parallel with each other and are assembled together to form a refrigerant passage; and    a plurality of columns formed inside of the flat tube, wherein each of the plurality of columns is formed by joining together top portions of swelling portions, which swell from interior surfaces of the first and second walls by applying external pressures to exterior surfaces of the first and second walls to cave in respectively and which are arranged opposite in connection with each other inside of the flat tube, and wherein each of the plurality of columns has a prescribed sectional shape which corresponds to an elliptical shape or an elongated circular shape each defined by a short length and a long length,    wherein the plurality of columns are arranged to align long lengths thereof along a length direction of the flat tube in such a manner that obliquely adjacent columns, which are arranged adjacent to each other obliquely with respect to the length direction of the tube, are arranged at different locations but are partly overlapped with each other with long lengths thereof in view of a width direction perpendicular to the length direction of the flat tube.    
     
     
         2 . A heat exchanger according to  claim 1  wherein the flat tube is constructed using side walls which are arranged at side ends of the first and second walls and on which a plurality of semi-columns each having a semi-shape of the column are formed in connection with the plurality of columns in such a manner that each of the plurality of semi-columns is arranged obliquely adjacent to a selected column to partly overlap with its front-end portion or its back-end portion.  
     
     
         3 . A heat exchanger comprising: 
 a flat tube constructed by a first wall and a second wall which are arranged opposite and apart in parallel with each other and are assembled together to form a refrigerant passage; and    a plurality of columns each having a prescribed sectional shape corresponding to an elliptical shape or an elongated circular shape each defined by a short length d 1  and a long length d 2 , wherein the plurality of columns are arranged between the first and second walls and are arranged to align long lengths thereof along a length direction of the flat tube such that obliquely adjacent columns, which are arranged adjacent to each other obliquely with respect to the length direction of the flat tube, are arranged at different locations but are partly overlapped with each other with long lengths thereof in view of a width direction perpendicular to the length direction of the flat tube,    wherein each of the plurality of columns has the prescribed sectional shape which is defined by a relationship of              2.0   ≤          2          1       ≤   3.0     ,                     and wherein using a first center distance p 1  being measured between the obliquely adjacent columns in the width direction of the flat tube and a second center distance p 2  being measured between the obliquely adjacent columns in the length direction of the flat tube, the plurality of columns are arranged to meet relationships of            1.5   ≤     p1   d1     ≤     3.0                 and                 0.5     ≤     p2   d2     ≤     1.5   .                       
     
     
         4 . A heat exchanger comprising: 
 a flat tube constructed by a first wall and a second wall which are arranged opposite and apart in parallel with each other and are assembled together to form a refrigerant passage;    a plurality of columns each having a prescribed sectional shape corresponding to an elliptical shape or an elongated circular shape each defined by a short length and a long length, wherein the plurality of columns are arranged between the first and second walls and are arranged to align long lengths thereof being slanted with respect to a length direction of the flat tube such that the long length of the column is slanted with a prescribed angle of inclination to the length direction of the flat tube.    
     
     
         5 . A heat exchanger according to  claim 4  wherein the prescribed angle of inclination is set within a range of ±7°.  
     
     
         6 . A heat exchanger comprising: 
 a flat tube constructed by a first wall and a second wall which are arranged opposite and apart in parallel with each other and are assembled together to form a refrigerant passage; and    a plurality of columns each having a prescribed sectional shape corresponding to an elliptical shape or an elongated circular shape each defined by a short length d 1  and a long length d 2 , wherein each of the plurality of columns is formed by joining together top portions of swelling portions which swell from interior surfaces of the first and second walls by applying external pressures to exterior surface of the first and second walls respectively and which are arranged opposite in connection with each other inside of the flat tube, and wherein the plurality of columns are arranged to align long lengths thereof along a length direction of the flat tube such that obliquely adjacent columns, which are arranged adjacent to each other obliquely with respect to the length direction of the flat tube, are arranged at different locations but are partly overlapped with each other with long lengths thereof in view of a width direction perpendicular to the length direction of the flat tube,    wherein each of the plurality of columns has the sectional shape which is defined by a relationship of              2.0   ≤          2          1       ≤   3.0     ,                     and wherein using a first center distance p 1  being measured between the obliquely adjacent columns in the width direction of the flat tube and a second center distance p 2  being measured between the obliquely adjacent columns in the length direction of the flat tube, the plurality of columns are arranged to meet relationships of            1.5   ≤     p1   d1     ≤     3.0                 and                 0.5     ≤     p2   d2     ≤     1.5   .                       
     
     
         7 . A heat exchanger comprising: 
 a flat tube constructed by a first wall and a second wall which are arranged opposite and apart in parallel with each other and are assembled together to form a refrigerant passage; and    a plurality of columns each having a prescribed sectional shape corresponding to an elliptical shape or an elongated circular shape each defined by a short length and a long length, wherein each of the plurality of columns is formed by joining together top portions of swelling portions which swell from interior surfaces of the first and second walls by applying external pressures to exterior surface of the first and second walls respectively and which are arranged opposite in connection with each other inside of the flat tube,    wherein the plurality of columns are arranged to align long lengths thereof being slanted with respect to a length direction of the flat tube such that the long length of the column is slanted with a prescribed angle of inclination to the length direction of the flat tube,    and wherein the plurality of columns are arranged to adjoin with each other such that obliquely adjacent columns, which are arranged adjacent to each other obliquely with respect to the length direction of the flat tube, are arranged at different locations but are partly overlapped with each other with long lengths thereof in view of a width direction perpendicular to the length direction of the flat tube.    
     
     
         8 . A heat exchanger according to  claim 7  wherein the prescribed angle of inclination is set within a range of ±7°.  
     
     
         9 . A heat exchanger comprising: 
 a flat tube constructed by a first wall and a second wall which are arranged opposite and apart in parallel with each other and are assembled together to form a refrigerant passage; and    a plurality of columns each having a prescribed sectional shape corresponding to an elliptical shape or an elongated circular shape each defined by a short length and a long length, wherein the plurality of columns are arranged between the first and second walls and are arranged to align long lengths thereof in a length direction of the flat tube and wherein the plurality of columns are arranged in a gradually concentrated manner along a refrigerant flow direction corresponding to the length direction of the flat tube.    
     
     
         10 . A heat exchanger according to  claim 9  wherein the plurality of columns are arranged to gradually increase in number, size or density in the refrigerant flow direction.  
     
     
         11 . A heat exchanger comprising: 
 a flat tube constructed by a first wall and a second wall which are arranged opposite and apart in parallel with each other and are assembled together to form a refrigerant passage; and    a plurality of columns each having a prescribed sectional shape corresponding to an elliptical shape or an elongated circular shape each defined by a short length and a long length, wherein the plurality of columns are arranged between the first and second walls and are arranged to align long lengths thereof in a length direction of the flat tube and wherein the plurality of columns are arranged in a gradually deconcentrated manner along a refrigerant flow direction corresponding to the length direction of the flat tube.    
     
     
         12 . A heat exchanger according to  claim 11  wherein the plurality of columns are arranged to gradually decrease in number, size or density in the refrigerant flow direction.  
     
     
         13 . A heat exchanger comprising: 
 a plurality of tubes each of which has a flat shape and contains a plurality of columns therein, wherein each of the plurality of columns has a prescribed sectional shape corresponding to an elliptical shape or an elongated circular shape each defined by a short length and a long length and wherein the plurality of columns are arranged to align long lengths thereof along a length direction of the tube such that obliquely adjacent columns, which are arranged adjacent to each other obliquely with respect to the length direction of the tube, are arranged at different locations but are partly overlapped with each other with long lengths thereof in view of a width direction perpendicular to the length direction of the tube;    a plurality of corrugated fins, each of which is arranged between the tubes such that crest portions are brought into contact with an exterior surface of the tube; and    two head pipes which are arranged apart from each other with a prescribed interval of distance therebetween and between which the plurality of tubes and the plurality of corrugated fins are arranged, so that both ends of a refrigerant passage formed inside of the tube communicate with insides of the two head pipes respectively.    
     
     
         14 . A heat exchanger according to  claim 13  wherein each of the plurality of tubes is constructed by bending a flat plate to form a first wall and a second wall, which are arranged opposite to each other with a prescribed interval of distance therebetween to provide the refrigerant passage, wherein swelling portions are formed to swell from interior surfaces of the first and second walls by applying external pressures to the first and second walls respectively and are arranged at selected positions by which top portions of the swelling portions are correspondingly brought into contact with each other to form the columns.  
     
     
         15 . A heat exchanger according to  claim 14  wherein the first and second walls are bonded together at selected portions by brazing to form the tube, while the top portions of the swelling portions are bonded together by brazing to form the columns.  
     
     
         16 . A manufacturing method of a heat exchanger comprising the steps of: 
 constructing a plurality of tubes each having a flat shape by bending flat plates whose surfaces are clad with brazing material, wherein a plurality of swelling portions are formed to swell from interior surfaces of the tube and their top portions are correspondingly paired and brought into contact with each other to form a plurality of columns inside of the tube;    providing a plurality of corrugated fins, which are respectively arranged between the plurality of tubes;    assembling the plurality of tubes and the plurality of corrugated fins together with two head pipes such that the plurality of tubes and the plurality of corrugated fins are alternatively arranged in elevation and are horizontally held between the two head pipes, wherein each of the plurality of tubes having refrigerant passages communicates with the two head pipes respectively; and    placing the plurality of tubes, the plurality of corrugated fins and the two head pipes which are assembled together into a heating furnace to heat for a prescribed time.    
     
     
         17 . A manufacturing method of the heat exchanger according to  claim 16  further comprising the steps of: 
 forming the plurality of swelling portions to swell from an interior surface of the flat plate at selected positions by press; and  
 bending the flat plate to form a first wall and a second wall, which are arranged opposite to each other with a prescribed interval of distance therebetween to form a tube, wherein the first and second walls are adjusted in position such that the plurality of swelling portions are correspondingly paired with each other in elevation and top portions thereof are correspondingly brought into contact with each other to form a plurality of columns inside of the tube.  
 
     
     
         18 . A manufacturing method of the heat exchanger according to  claim 16  wherein the plurality of columns each having a prescribed sectional shape corresponding to an elliptical shape or an elongated circular shape defined by a short length d 1  and a long length d 2  are arranged to align long lengths thereof in a length direction of the tube such that obliquely adjacent columns, which are arranged adjacent to each other obliquely with respect to the length direction of the tube, are arranged at different locations but are partly overlapped with each other with long lengths thereof in view of a width direction perpendicular to the length direction of the tube, 
 wherein each of the plurality of columns is defined in sectional shape by a relationship of  
         2.0   ≤          2          1       ≤     3.0   .                     
 and wherein using a first center distance p 1  being measured between the obliquely adjacent columns in the width direction of the tube and a second center distance p 2  being measured between the obliquely adjacent columns in the length direction of the tube, the plurality of columns are arranged to meet relationships of  
         1.5   ≤     p1   d1     ≤     3.0                 and                 0.5     ≤     p2   d2     ≤     1.5   .