Finned heat exchange tube and process for forming same

Abstract

A finned heat exchange tube includes a metal cylindrical central tube having an outer surface and a metal fin helically disposed on and in thermally conductive contact with the outer surface of the tube. The cross-section of the fin is trapezoidal in shape, with a longer and a shorter base, the longer base being in contact with the outer surface of the tube. Alternatively, the fin can have a cross-section substantially rectangular in shape, having rounded comers and sides of longer and shorter dimensions perpendicular to one another, a side of the shorter dimension being in contact with the outer surface of the tube. A process for forming a heat exchanger tube comprises helically winding and securing a metal fin on an outer surface of a metal cylindrical central tube. The fin, which is in thermally conductive contact with the central tube, has a cross-section that can be trapezoidal or substantially rectangular in shape.

What is claimed is:  
     
         1 . A finned heat exchange tube comprising: 
 a metal cylindrical central tube having an outer surface; and    a metal fin helically disposed on and in thermally conductive contact with said outer surface of said central tube, said fin having a cross-section selected from the group consisting of: a trapezoidal shape comprising a longer base and a shorter base, said longer base being in contact with said outer surface of said central tube; and a substantially rectangular shape having rounded comers and sides of longer and shorter dimensions perpendicular to one another, a side of said shorter dimension being in contact with said outer surface of said tube.    
     
     
         2 . The heat exchange tube of  claim 1  wherein said fin cross-section has said trapezoidal shape.  
     
     
         3 . The heat exchange tube of  claim 1  wherein said fin cross-section has said substantially rectangular shape.  
     
     
         4 . The heat exchange tube of  claim 1  wherein said central tube and said metal fins are formed from the same metal.  
     
     
         5 . The heat exchange tube of  claim 1  wherein said central tube and said metal fins are formed from different metals.  
     
     
         6 . The heat exchange tube of  claim 1  wherein said central tube is formed from a metal selected from the group consisting of copper, copper-nickel alloy, and stainless steel.  
     
     
         7 . The heat exchange tube of  claim 1  wherein said fin is formed from a metal selected from the group consisting of copper and aluminum.  
     
     
         8 . The heat exchanger tube of  claim 1  wherein said central tube has an outside diameter of up to and including about 1 inch.  
     
     
         9 . The heat exchanger tube of  claim 8  wherein said central tube has an outside diameter of about ¼ inch.  
     
     
         10 . The heat exchanger tube of  claim 1  wherein said fin has a height of up to and including about {fraction (3/16)} inch.  
     
     
         11 . The heat exchanger tube of  claim 10  wherein said fin has a height of about {fraction (1/16)} inch.  
     
     
         12 . The heat exchanger tube of  claim 1  wherein said fin is connected to said outer surface of said central tube by adhering means.  
     
     
         13 . The heat exchanger tube of  claim 12  wherein said adhering means is selected from the group consisting of solder and polymeric adhesive.  
     
     
         14 . A process for forming a heat exchanger tube, said process comprising: 
 helically winding and securing a metal fin on an outer surface of a metal cylindrical central tube, said fin being in thermally conductive contact with said outer surface of said central tube and having a cross-section selected from the group consisting of: a trapezoidal shape comprising a longer base and a shorter base, said longer base being in contact with said outer surface of said central tube; and a substantially rectangular shape having rounded comers and sides of longer and shorter dimensions perpendicular to one another, a side of said shorter dimension being in contact with said outer surface of said tube.    
     
     
         15 . The process of  claim 14  wherein said fin cross-section has said trapezoidal shape.  
     
     
         16 . The process of  claim 14  wherein said fin cross-section has said substantially rectangular shape.  
     
     
         17 . The process of  claim 14  wherein said central tube and said metal fins are formed from the same metal or from different metals.  
     
     
         18 . The process of  claim 14  wherein said central tube is formed from a metal selected from the group consisting of copper, copper-nickel alloy, and stainless steel, and said fin is formed from a metal selected from the group consisting of copper and aluminum.  
     
     
         19 . The process of  claim 14  wherein said central tube has an outside diameter of up to and including about one inch, and said fin has a height of up to and including about {fraction (3/16)} inch.  
     
     
         20 . The process of  claim 19  wherein said central tube has an outside diameter of about ¼ inch, and said fin has a height of about {fraction (1/16)} inch.  
     
     
         21 . The process of  claim 14  wherein said fin is connected to said outer surface of said central tube by adhering means selected from the group consisting of solder and polymeric adhesive.  
     
     
         22 . A finned heat exchange tube comprising: 
 a metal cylindrical central tube having an outer surface, said tube being formed from copper or stainless steel and having an outside diameter of about ¼ inch.; and    a metal fin helically disposed on and in thermally conductive contact with said outer surface of said central tube, said fin being formed from copper and having a height of about {fraction (1/16)} inch, said fin further having a cross-section selected from the group consisting of: a trapezoidal shape comprising a longer base and a shorter base, said longer base being in contact with said outer surface of said central tube; and a substantially rectangular shape having rounded comers and sides of longer and shorter dimensions perpendicular to one another, a side of said shorter dimension being in contact with said outer surface of said tube.