High pressure header and heat exchanger and method of making the same

Abstract

A method of providing volume production of highly pressure resistant headers ( 10 ), ( 12 ) is provided and allows the headers ( 10 ), ( 12 ) to be formed of a header structure ( 10 ), ( 12 ) with a relatively thin wall portion ( 32 ) and a relatively thick wall portion ( 30 ). A strip ( 40 ) is utilized to provide the desired thickness at the thin wall portion ( 32 ) while allowing both the thin wall portion ( 32 ) and the strip ( 40 ) to have tube slots ( 34 ), ( 42 ) formed therein by a one step punching operation.

1 . A method of making a high pressure resistant header for a heat exchanger, comprising the steps of: 
 (a) providing an elongated header structure including a pair of side-by-side longitudinally extending passages, the passages surrounded by a wall of sufficient thickness to resist deformation when a fluid is placed within said passages at an operating pressure at which deformation is to be resisted;    (b) thinning the wall along its length by providing a first mating exterior surface on a part thereof so that the wall, at said first mating exterior surface, is sufficiently thin that tube slots may be punched in said wall at said first mating surface extending through said wall into said passages;    (c) punching tube slots at predetermined spaced intervals in said wall at said first mating surface, with some of the slots extending into one of the passages and other of the slots extending into the other of the passages;    (d) providing an elongated strip having a second-mating surface complementary to said first mating surface and of a thickness such that the combined thickness of the strip and said wall at its first mating surface is about equal to or greater than said sufficient thickness of said wall;    (e) punching tube slots in said strip at said predetermined spaced intervals;    (f) abutting the second mating surface of said strip to the first mating surface of said header structure with the tube slots in each being aligned with one another; and    (g) bonding the strip to the header structure along their respective lengths to provide a unitary header with tube slots therein.    
   
   
       2 . The method of  claim 1  wherein both said mating surfaces are flat surfaces.  
   
   
       3 . The method of  claim 2  wherein steps (a) and (b) are performed simultaneously by extrusion of said header structure.  
   
   
       4 . The method of  claim 1  wherein steps (a) and (b) are performed simultaneously by extrusion of said header structure.  
   
   
       5 . The method of  claim 1  wherein step (b) is performed by providing a strip receiving groove in said part of said header structure exterior surface.  
   
   
       6 . The method of  claim 5  wherein said groove has a flat bottom surface defining said first mating surface and said second mating surface is flat.  
   
   
       7 . The method of  claim 1  wherein step (e) is performed by punching the tube slots in said strips to be of substantially the same size and shape as the tube slots in the first mating surface.  
   
   
       8 . The method of  claim 1  wherein step (b) is performed by forming a strip receiving groove in said wall.  
   
   
       9 . The method of  claim 8  wherein step (f) is preceded by the step of providing tabs on opposite sides of the strip receiving groove and succeeded by the step of deforming the tabs over the strip.  
   
   
       10 . The method of  claim 1  wherein step (f) is preceded by the steps of providing tabs on opposite sides of said first mating exterior surface and step (f) succeeded by and step (g) preceded by the step of deforming the tabs over opposite edges of the strip.  
   
   
       11 . The method of  claim 1  wherein said passages of step (a) are provided with a cylindrical shape.  
   
   
       12 . The method of  claim 1  wherein said passages of step (a) are provided with a non-cylindrical shape.  
   
   
       13 . A header for a high pressure heat exchanger, comprising: 
 an elongated tubular like element having a pair of side-by-side longitudinally extending passages and a tube receiving side, said element being a unitary structure having a relatively thick wall partially surrounding said passages and a relatively thin wall at said tube receiving side;    a first mating exterior surface defined by a relief at said relatively thin wall of said element;    a plurality of punched first tube receiving slots at said first mating surface in fluid communication with said passages and located at predetermined spaced intervals;    an elongated strip having a second mating surface complementary to and abutted against said first mating surface such that the thickness of said strip and said thin wall is substantially equal to or greater than the thickness of said thick wall;    a plurality of second, punched tube receiving slots in said strip and located therein at said predetermined intervals, said second tube receiving slots being aligned with said first tube receiving slots; and    a joint bonding said element and said strip together.    
   
   
       14 . The header of  claim 13  wherein both said first and second mating surfaces are flat.  
   
   
       15 . The header of  claim 13  wherein said joint is a brazed joint.  
   
   
       16 . The header of  claim 13  wherein both said first and second mating surfaces are flat, and said joint is a brazed joint.  
   
   
       17 . The header of  claim 16  wherein said first mating surface is defined by the bottom of a groove formed in said exterior and said strip is located in said groove.  
   
   
       18 . The header of  claim 13  wherein said passages are cylindrical passages.  
   
   
       19 . The header of  claim 13  wherein said passages are non-cylindrical passages.  
   
   
       20 . The header of  claim 13  wherein said tube slots are elongated in the direction of elongation of said element.  
   
   
       21 . The header of  claim 13  including tabs on opposite sides of said relief and deformed over opposite sides of said elongated strip.  
   
   
       22 . A high pressure heat exchanger comprising: 
 at least one header defined by an elongated tubular like element having a pair of side-by-side longitudinally extending passages and a tube receiving side, said element being a unitary structure having a relatively thick wall partially surrounding said passages and a relatively thin wall at said tube receiving side;    a first mating exterior surface defined by a relief at said relatively thin wall of said element;    a plurality of punched first tube receiving slots at said first mating surface in fluid communication with said passages and located at predetermined spaced intervals;    an elongated strip having a second mating surface complementary to and abutted against said first mating surface such that the thickness of said strip and said thin wall is substantially equal to or greater than the thickness of said thick wall;    a plurality of second, punched tube receiving slots in said strip and located therein at said predetermined intervals, said second tube receiving slots being aligned with said first tube receiving slots;    a joint bonding said element and said strip together;    a plurality of tubes, each of flattened cross section, having their ends disposed within said tube slots; and    fins extending between and bonded to adjacent ones of said tubes.    
   
   
       23 . The heat exchanger of  claim 22  wherein said fins are serpentine fins.  
   
   
       24 . The heat exchanger of  claim 22  wherein both said first and second mating surfaces are flat.  
   
   
       25 . The heat exchanger of  claim 22  wherein said first mating surface is on the exterior of said element.  
   
   
       26 . The heat exchanger of  claim 22  wherein said joint is a brazed joint.  
   
   
       27 . The heat exchanger of  claim 22  wherein both said first and second mating surfaces are flat, said joint is a brazed joint.  
   
   
       28 . The heat exchanger of  claim 27  wherein said first mating surface is defined by the bottom of a groove formed in said exterior and said strip is located in said groove.  
   
   
       29 . The heat exchanger of  claim 22  wherein said passages are cylindrical passages.  
   
   
       30 . The heat exchanger of  claim 22  wherein said passages are non-cylindrical passages.  
   
   
       31 . The heat exchanger of  claim 22  including tabs on opposite sides of said relief and deformed over opposite sides of said elongated strip.  
   
   
       32 . The heat exchanger of  claim 22  wherein said plurality of the tubes comprises a first group of tubes having their ends disposed within said tube slots in fluid communication with one of said passages, and a second group of tubes having their ends disposed within said tube slots in fluid communication with the other of said passages.  
   
   
       33 . The heat exchanger of  claim 22  wherein each of said ends of each of said plurality of tubes is notched with a first part on one side of said notch disposed within said tube slots in fluid communication with one of said passages, and a second part on the other side of said notch disposed within said tube slots in fluid communication with the other of said passages.  
   
   
       34 . The heat exchanger of  claim 22  wherein each of said tubes of said plurality of tubes include a pair of parallel legs and a bend joining said legs at a location remote from said at least one header, one of said legs having an end disposed within said tube slots in fluid communication with one of said passages, and the other of said legs having another end disposed within said tube slots in fluid communication with the other of said passages.