Folded, bent and re-expanded heat exchanger tube and assemblies

Abstract

A heat exchanger assembly of the side-entry type includes at least one fin set and an elongated heat exchanger tube having a collapsed sidewall extending substantially the length of the tube which permits the bending of the elongated heat exchanger tube at the return bend portions and permits expansion of the elongated tube to engage the fin set. Method and apparatus for making the elongated heat exchanger tube having the collapsed sidewall substantially extending the length of the tube as well as methods of making heat exchanger assemblies are

1 . For use in a heat exchanger assembly of the side-entry type having at least one fin set, an elongated heat exchanger tube having a collapsed sidewall extending substantially the length of said tube which permits the bending of the elongated heat exchanger tube at the return bend portion and permits expansion of said elongated tube to engage the at least one fin set.  
     
     
         2 . The heat exchanger tube in accordance with  claim 1  wherein said elongated heat exchanger tube has a wall thickness of between about 0.010 to 0.030 inches.  
     
     
         3 . The heat exchanger tube in accordance with  claim 2  wherein the return bend portion of said elongated heat exchanger tube is bent about a mandrel.  
     
     
         4 . The heat exchanger tube in accordance with  claim 3  wherein said mandrel has a radius of less than about 0.5 inches.  
     
     
         5 . The heat exchanger tube in accordance with  claim 1  wherein the cross-section of the collapsed sidewall is an elongated recess extending substantially the length of said heat exchanger tube.  
     
     
         6 . The heat exchanger tube in accordance with  claim 5  wherein said collapsed sidewall substantially engages the interior surface of the elongated tube.  
     
     
         7 . The heat exchanger tube in accordance with  claim 1  wherein said elongated heat exchanger tube having a collapsed sidewall is inserted within an outer substantially circular heat exchanger tube to permit expansion of said tube having a collapsed sidewall to form a bond between the heat exchanger tubes.  
     
     
         8 . The heat exchanger tube in accordance with  claim 7  wherein said expansion of said tube having a collapsed sidewall within said outer tube provides an elongated port extending the length between the walls of the bonded tubes.  
     
     
         9 . The heat exchanger tube in accordance with  claim 8  wherein said elongated heat exchanger tube having a collapsed sidewall includes a heating wire positioned along its length therein such that expansion of the collapsed side wall tube positions said heating wire within said elongated port between the heat exchanger tubes.  
     
     
         10 . For use in a heat exchanger assembly of the side-entry type having at least one fin set, an elongated heat exchanger tube having substantially circular end portions and a collapsed sidewall portion extending substantially the length of said tube between said end portion which permits the bending of the elongated heat exchanger tube at the return bend portion and permits expansion of said elongated tube to engage the at least one fin set.  
     
     
         11 . The heat exchanger tube in accordance with  claim 10  wherein said elongated heat exchanger tube has a wall thickness of between about 0.010 to 0.030 inches.  
     
     
         12 . The heat exchanger tube in accordance with claim  11  wherein the return bend portion of said elongated heat exchanger tube is bent about a mandrel.  
     
     
         13 . The heat exchanger tube in accordance with  claim 3  wherein said mandrel has a radius of less than about 0.5 inches.  
     
     
         14 . The heat exchanger tube in accordance with  claim 10  wherein the cross-section of the collapsed sidewall portion is an elongated recess extending substantially the length of said heat exchanger tube.  
     
     
         15 . The heat exchanger tube in accordance with  claim 14  wherein said collapsed sidewall portion substantially engages the interior surface of the elongated tube.  
     
     
         16 . The heat exchanger tube in accordance with  claim 10  wherein said elongated heat exchanger tube having a collapsed sidewall portion is inserted within an outer substantially circular heat exchanger tube to permit expansion of said tube having a collapsed sidewall portion to form a bond between the heat exchanger tubes.  
     
     
         17 . The heat exchanger tube in accordance with  claim 16  wherein said expansion of said collapsed sidewall portion within said outer tube provides an elongated port extending the length between the walls of the bonded tubes.  
     
     
         18 . The heat exchanger tube in accordance with  claim 17  wherein said collapsed sidewall portion includes a heating wire positioned along its length therein such that expansion of the collapsed sidewall portion positions said heating wire in said elongated port between the heat exchanger tubes.  
     
     
         19 . A method of making an elongated tube for use in a heat exchanger assembly of the side-entry type, including the steps of: 
 extruding an elongated tube having a substantially circular cross-section;    cutting the extruded elongated tube to the desired length of the finished heat exchanger assembly; and    passing the cut extruded tube through a folding mechanism to provide an elongated tube having a collapsed sidewall extending substantially the length of the elongated tube.    
     
     
         20 . The method in accordance with  claim 19  wherein said extruded elongated tube has a wall thickness of between about 0.010 to 0.030 inches.  
     
     
         21 . The method in accordance with  claim 19  wherein said extruded elongated tube is comprised of aluminum.  
     
     
         22 . The method in accordance with  claim 19  wherein said folding mechanism engages the cut elongated tube to provide said collapsed sidewall substantially engaging the inner wall of the tube.  
     
     
         23 . The method in accordance with  claim 22  wherein said folding mechanism includes a die having a forming cavity and a compression member which engages said cut extruded tube.  
     
     
         24 . A method of making a heat exchanger assembly including a thin-walled heat exchanger tube and at least one fin set having fin holes, including in combination: 
 passing the thin-walled heat exchanger tube through a folding mechanism to provide an elongated tube having a collapsed sidewall portion extending substantially the length of the tube;    rotating the elongated collapsed heat exchanger tube about a forming mandrel having a mandrel outer surface while maintaining and positioning said collapsed portion opposite said mandrel outer surface to provide a spirally wrapped serpentine heat exchanger tube;    aligning said spirally wrapped serpentine with the fine holes of said at least one fin set; and    expanding said collapsed sidewall portion of the heat exchanger tube to secure the fin set to the expanded thin-walled heat exchanger tube to provide the heat exchanger assembly.    
     
     
         25 . The method in accordance with  claim 24  wherein said thin-walled elongated heat exchanger tube has a wall thickness of between about 0.010 to 0.030 inches.  
     
     
         26 . The method in accordance with  claim 24  wherein said mandrel outer surface has a multiple diameter to provide return bend portions of said spirally wrapped serpentine heat exchanger tube having different radii.  
     
     
         27 . The method in accordance with  claim 24  wherein said mandrel outer surface has a uniform diameter to provide the return bend portions of said spirally wrapped serpentine heat exchanger tube having substantially the same radii.  
     
     
         28 . The method in accordance with  claim 24  wherein said method further includes the step of inserting said elongated heat exchanger tube having a collapsed sidewall within an outer substantially circular heat exchanger tube to permit expanding of said tube having a collapsed sidewall to form a bond between the heat exchanger tubes.  
     
     
         29 . The method in accordance with  claim 28  wherein said step of expanding of said tube having a collapsed sidewall is within said outer tube to provide an elongated port extending the length between the walls of the bonded tubes.  
     
     
         30 . The method in accordance with  claim 29 , wherein said elongated heat exchanger tube having a collapsed sidewall includes a heating wire positioned along its length therein such that the expanding of the collapsed sidewall tube within said outer tube positions said heating wire within said elongated port between the heat exchanger tubes.  
     
     
         31 . A method of making a heat exchanger assembly including a thin-walled heat exchanger tube and at least one fin set having fin holes therein, including in combination: 
 passing the thin-walled heat exchanger tube through a folding mechanism to provide an elongate tube having a collapsed sidewall portion extending substantially the length of the tube;    inserting said thin-walled heat exchanger tube having a collapsed sidewall portion through said holes of said at least one fin set, to position said at least one fin set on said tube;    rotating the elongated collapsed heat exchanger tube and said associated at least one fin set about a forming mandrel outer surface to provide a spirally wrapped serpentine heat exchanger tube and associated fin set; and    expanding said collapsed sidewall portion of the heat exchanger tube to secure the at least one fin set to the expanded thin-walled heat exchanger tube to provide the heat exchanger assembly.    
     
     
         32 . The method in accordance with  claim 31  wherein said thin-walled heat exchanger tube has wall-thickness of between about 0.010 to 0.030 inches.  
     
     
         33 . The method in accordance with  claim 31  wherein said folding mechanism includes a die having a forming cavity and a compression member which engages said cut extruded tube.  
     
     
         34 . A method of making a heat exchanger assembly including a thin-walled heat exchanger tube and at least one fin set having fin holes therein, including in combination: 
 passing the thin-walled heat exchanger tube through a folding mechanism to provide an elongated tube having a collapsed sidewall portion extending substantially the length of the tube;    inserting said tube having a collapsed sidewall portion within an outer substantially circular heat exchanger tube;    positioning said thin-walled heat exchanger tube having a collapsed sidewall portion and said outer tube through said holes of said at least one fin set, to position said at least one fin set on said outer tube;    rotating the elongated collapsed heat exchanger tube, the outer tube and said associated at least one fin set about a forming mandrel outer surface to provide a spirally wrapped serpentine heat exchanger tube and associated fin set; and    expanding said collapsed sidewall portion of the heat exchanger tube within said outer tube to form a bond between the tubes and to secure the at least one fin set to the tubes to provide the heat exchanger assembly.    
     
     
         35 . The method in accordance with  claim 31  wherein said thin-walled heat exchanger tube has wall-thickness of between about 0.010 to 0.030 inches.  
     
     
         36 . The method in accordance with  claim 31  wherein said folding mechanism includes die having a forming cavity and a compression member which engages said cut extruded tube.  
     
     
         37 . The method in accordance with  claim 34  wherein said step of expanding of said tube having a collapsed sidewall within said outer tube provides an elongated port extending the length between the walls of the bonded tubes.  
     
     
         38 . The method in accordance with  claim 37  wherein said method further includes the step of positioning a heating wire along the collapsed sidewall portion prior to inserting said collapsed tube with said outer tube such that during the expanding step the collapsed sidewall tube positions said heating wire within said elongated port between the heat exchanger tubes.  
     
     
         39 . A method of making a heat exchanger assembly including a thin-walled heat exchanger tube and at least one fin set wherein the at least one fin set is an accordion-like sheet of heat radiating material folded back and forth upon itself and having fin slots at the junction of each fold, including in combination: 
 passing the thin-walled heat exchanger tube through a folding mechanism to provide an elongated tube having a collapsed sidewall portion extending substantially the length of the tube;    spiral wrapping the elongated collapsed heat exchanger tube about a forming mandrel and said at least one fin set to engage said spirally wrapped serpentine heat exchanger tube with said slots of said at least one fin set; and    expanding said collapsed sidewall portion of the heat exchanger tube to secure the fin set to the expanded spiral wrapped thin-walled heat exchanger tube to complete the heat exchanger assembly.    
     
     
         40 . The method in accordance with  claim 39  wherein said thin-walled heat exchanger tube has a wall-thickness between about 0.010 to 0.030 inches.  
     
     
         41 . The method in accordance with  claim 39  wherein said mandrel outer surface has a multiple diameter to provide return bend portions of said spirally wrapped serpentine heat exchanger tube having different radii.  
     
     
         42 . The method in accordance with  claim 39  wherein said mandrel outer surface has a uniform diameter to provide the return bend portions of said spirally wrapped serpentine heat exchanger tube having substantially the same radii.  
     
     
         43 . The method in accordance with  claim 39  wherein said folding mechanism includes a die having a forming cavity and a compression member which engages said cut extruded tube.  
     
     
         44 . A method of making a heat exchanger assembly including a thin-walled heat exchanger tube and at least one fin set wherein the at least one fin set is an accordion-like sheet of heat radiating material folded back and forth upon itself and having fin slots at the junction of each fold, including in combination: 
 passing the thin-walled heat exchanger tube through a folding mechanism to provide an elongated tube having a collapsed sidewall portion extending substantially the length of the tube;    inserting said tube having a collapsed sidewall portion within an outer substantially circular heat exchanger tube;    wrapping the elongated collapsed heat exchanger tube and said outer tube about a forming mandrel and said at least one fin set to engage said spirally wrapped serpentine heat exchanger tubes with said slots of said at least one fin set; and    expanding said collapsed sidewall portion of the heat exchanger tube within said outer tube to secure the at least one fin set to the serpentine heat exchanger tubes to complete the heat exchanger assembly.    
     
     
         45 . The method in accordance with  claim 44  wherein said thin-walled heat exchanger tube has a wall-thickness between about 0.010 to 0.030 inches.  
     
     
         46 . The method in accordance with  claim 44  wherein said mandrel outer surface has a multiple diameter to provide return bend portions of said spirally wrapped serpentine heat exchanger tubes having different radii.  
     
     
         47 . The method in accordance with  claim 44  wherein said mandrel outer surface has a uniform diameter to provide the return bend portions of said spirally wrapped serpentine heat exchanger tubes having substantially the same radii.  
     
     
         48 . The method in accordance with  claim 44  wherein said folding mechanism includes a die having a forming cavity and a compression member which engages said cut extruded tube.