Heat exchangers with corrugated heat exchange elements of improved strength

Abstract

A corrugated fin or turbulizer for a heat exchanger comprises a series of corrugations with parallel side walls. The side walls are provided with a series of parallel slits between which one-sided or two-sided louvers are defined. Each of the louvers has first and second edges extending along an adjacent pair of slits, and at least one bend located between the edges, thereby causing at least one of the edges of the louver to project outwardly of the plane of the side wall, and providing the side wall with improved crush resistance. The corrugations may preferably be rectangular or trapezoidal in form, having generally flat top and bottom surfaces defined by two closely-spaced bends. The top and bottom surfaces may preferably be provided with protrusions, at least some of which extend close to the bends. This assists in creating localized areas of weakness along which the bends can be formed cleanly.

1 . A corrugated heat exchange element for a heat exchanger, the heat exchange element comprising: 
 a plurality of side walls interconnected by a plurality of top and bottom walls, wherein each of the side walls defines a plane and extends parallel to a longitudinal axis, wherein each of the side walls extends between an adjacent one of the top walls and an adjacent one of the bottom walls, and wherein longitudinal bends are formed between each side wall and the adjacent top and bottom walls such that spaces for flow of a heat exchange fluid are defined between adjacent ones of said side walls; and    at least one group of adjacent louvers provided in at least some of the side walls, wherein each group of adjacent louvers is defined by a plurality of parallel slits extending between the top wall and the bottom wall of the side wall substantially perpendicular to the axis;    wherein each of the adjacent louvers comprises an area of the side wall between an adjacent pair of said slits and includes:    (i) a first edge extending along a first slit of the adjacent pair of slits;    (ii) a second edge extending along a second slit of the adjacent pair of slits; and    (iii) at least one bend located between the first and second edges of the louver which causes at least one of the edges of the louver to project outwardly of the plane of the side wall.    
   
   
       2 . The corrugated heat exchange element of  claim 1 , wherein each of the slits is bounded by the first edge of one of said louvers and the second edge of an adjacent one of said louvers.  
   
   
       3 . The corrugated heat exchange element of  claim 1 , wherein the first edge of each of the adjacent louvers projects outwardly of the plane of the side wall and the second edge of each of the louvers is located in the plane of the side wall.  
   
   
       4 . The corrugated heat exchange element of  claim 1 , wherein the first edges of all the adjacent louvers in each said group project outwardly from the same side of the side wall.  
   
   
       5 . The corrugated heat exchange element of  claim 1 , wherein both edges of each of the adjacent louvers project outwardly of the plane of the side wall, and wherein the first edge and the second edge of each louver project outwardly from opposite sides of the side wall.  
   
   
       6 . The corrugated heat exchange element of  claim 1 , wherein a single one of said bends is provided between the first and second edges of each of the adjacent louvers, wherein the single bend is angular and extends along a bend line parallel to the first and second edges of the louver to define an apex of the louver, and wherein the apex is located in the plane of the side wall.  
   
   
       7 . The corrugated heat exchange element of  claim 1 , wherein a first louver wall is defined between the apex and the first edge of the louver and a second louver wall is defined between the apex and the second edge of the louver.  
   
   
       8 . The corrugated heat exchange element of  claim 1 , wherein the first and second louver walls are substantially flat.  
   
   
       9 . The corrugated heat exchange element of  claim 7 , wherein the single bend defines an obtuse angle between the first and second louver walls.  
   
   
       10 . The corrugated heat exchange element of  claim 1 , wherein a plurality of said bends is provided between the first and second edges of each of the adjacent louvers, wherein each of the bends is angular and extends along a bend line parallel to the first and second edges of the louver, wherein each of the bends defines an obtuse angle.  
   
   
       11 . The corrugated heat exchange element of  claim 1 , wherein an overall obtuse angle is defined between a first edge portion of the louver proximate the first edge and a second edge portion of the louver proximate the second edge.  
   
   
       12 . The corrugated heat exchange element of  claim 10 , wherein two of said bends are provided between the first and second edges of each said louver so as to define a first edge portion between the first edge of the louver and a first one of the bends, a second edge portion between the second edge of the louver and a second one of the bends, and a central portion between the bends, and wherein the first edge and the second edge of each louver project outwardly from opposite sides of the side wall.  
   
   
       13 . The corrugated heat exchange element of  claim 12 , wherein the central portions of the louvers are substantially coplanar with the plane of the side wall.  
   
   
       14 . The corrugated heat exchange element of  claim 1 , wherein said at least one bend comprises an arcuate bend between the first and second edges of the louver, wherein an obtuse angle is formed between two lines which meet along a line bisecting the arcuate bend into two segments and which are tangential to the segments at their mid-points.  
   
   
       15 . The corrugated heat exchange element of  claim 1 , wherein an angle between the plane of the side wall and at least one of the edges of each louver is from about 20 to 30 degrees.  
   
   
       16 . The corrugated heat exchange element of  claim 15 , wherein the angle between the plane of the side wall and at least one of the edges of each louver varies among the louvers of each said group.  
   
   
       17 . The corrugated heat exchange element of  claim 16 , wherein the angle between the plane of the side wall and at least one of the edges of the louvers in each said group is progressively increased so that the louver edges extend outward to a progressively greater extent from one end of the group to the other.  
   
   
       18 . The corrugated heat exchange element of  claim 1 , wherein a spacing between adjacent slits is equidistant.  
   
   
       19 . The corrugated heat exchange element of  claim 1 , wherein a spacing between adjacent slits is variable.  
   
   
       20 . The corrugated heat exchange element of  claim 1 , wherein each of the side walls is provided with at least two groups of adjacent louvers, and wherein adjacent groups of louvers are spaced by a distance which is greater than a spacing between adjacent slits within said groups.  
   
   
       21 . The corrugated heat exchange element of  claim 1 , wherein at least some of the slits and the louvers have upper and lower ends which are in close proximity to the longitudinal bends between each side wall and the adjacent top and bottom walls, respectively.  
   
   
       22 . The corrugated heat exchange element of  claim 1 , wherein each of the top walls of the heat exchange element extends between a pair of longitudinal bends through which it is joined to adjacent ones of said side walls, and wherein each of the bottom walls of the heat exchange element extends between a pair of longitudinal bends through which it is joined to adjacent ones of said side walls.  
   
   
       23 . The corrugated heat exchange element of  claim 22 , wherein the side walls are substantially parallel to one another and substantially perpendicular to the top and bottom walls, such that the spaces between adjacent side walls are substantially rectangular in shape.  
   
   
       24 . The corrugated heat exchange element of  claim 22 , wherein the side walls are angled relative to one another and wherein the top and bottom walls are substantially parallel to one another, such that the spaces between adjacent side walls are substantially trapezoidal in shape.  
   
   
       25 . The corrugated heat exchange element of  claim 1 , wherein the top walls of the heat exchange element are substantially coplanar and the bottom walls of the heat exchange element are substantially coplanar.  
   
   
       26 . The corrugated heat exchange element of  claim 1 , wherein the top and bottom walls of the heat exchange element are generally flat and define top and bottom planes of the heat exchange element, wherein each of the top and bottom walls has a width defined by a transverse distance between an adjacent pair of said longitudinal bends, and wherein each of the longitudinal bends is located in either the top plane or the bottom plane.  
   
   
       27 . The corrugated heat exchange element of  claim 26 , wherein protrusions are provided in at least some of the top walls and at least some of the bottom walls of the heat exchange element.  
   
   
       28 . The corrugated heat exchange element of  claim 27 , wherein the protrusions in each of the top walls causes a portion of said top wall to deviate away from the top plane of the heat exchange element in a direction toward the bottom plane of the heat exchange element, and wherein the protrusions in each of the bottom walls causes a portion of said bottom wall to deviate away from the bottom plane of the heat exchange element in a direction toward the top plane of the heat exchange element.  
   
   
       29 . The corrugated heat exchange element of  claim 27 , wherein the protrusions extend continuously along the longitudinal axis.  
   
   
       30 . The corrugated heat exchange element of  claim 27 , wherein the protrusions are discontinuous along the longitudinal axis.  
   
   
       31 . The corrugated heat exchange element of  claim 30 , wherein the protrusions comprise ribs extending transversely across the width of the top and bottom walls.  
   
   
       32 . The corrugated heat exchange element of  claim 30 , wherein at least some of the ribs have opposite ends which are located in close proximity to the longitudinal bends.  
   
   
       33 . The corrugated heat exchange element of  claim 1 , wherein the heat exchange element is formed from a material which is relatively weakened along said longitudinal bends.  
   
   
       34 . The corrugated heat exchange element of  claim 1 , wherein the material is weakened by coining or by formation of a series of perforations located along the longitudinal bends.  
   
   
       35 . A plate-type heat exchanger, comprising: 
 a pair of plates secured together at their margins and spaced from one another between the margins to form a fluid flow passage, the fluid flow passage having a height and having an inlet opening and an outlet opening spaced apart along a plate axis;    a corrugated heat exchange element received inside said fluid flow passage and located between the inlet and outlet openings, the corrugated heat exchange element comprising:    (a) a plurality of side walls interconnected by a plurality of top and bottom walls which are in contact with the plates, wherein each of the side walls defines a plane and extends parallel to a longitudinal axis, wherein each of the side walls extends between an adjacent one of the top walls and an adjacent one of the bottom walls, and wherein longitudinal bends are formed between each side wall and the adjacent top and bottom walls such that spaces for flow of a heat exchange fluid are defined between adjacent ones of said side walls; and    (b) at least one group of adjacent louvers provided in at least some of the side walls, wherein each group of adjacent louvers is defined by a plurality of parallel slits extending between the top wall and the bottom wall of the side wall substantially perpendicular to the axis;    wherein each of the adjacent louvers comprises an area of the side wall between an adjacent pair of said slits and includes:    (i) a first edge extending along a first slit of the adjacent pair of slits;    (ii) a second edge extending along a second slit of the adjacent pair of slits; and    (iii) at least one bend located between the first and second edges of the louver which causes at least one of the edges of the louver to project outwardly of the plane of the side wall.    
   
   
       36 . The heat exchanger of  claim 35 , wherein the heat exchange element is oriented in the fluid flow passage with the axis parallel to the plate axis.  
   
   
       37 . The heat exchanger of  claim 35 , wherein the heat exchange element is oriented in the fluid flow passage with the axis transverse to the plate axis.  
   
   
       38 . The heat exchanger of  claim 35 , wherein the top and bottom walls of the heat exchange element are brazed to the plates.  
   
   
       39 . The heat exchanger according to  claim 35 , wherein the side walls are under vertical compression between the plates, and wherein the height of the side walls in their uncompressed state is slightly greater than the height of the fluid flow passage.  
   
   
       40 . A corrugated heat exchange element for a heat exchanger, the heat exchange element comprising: 
 a plurality of side walls interconnected by a plurality of top and bottom walls, wherein each of the side walls defines a plane and extends parallel to a longitudinal axis, wherein each of the side walls extends between an adjacent one of the top walls and an adjacent one of the bottom walls, and wherein longitudinal bends are formed between each side wall and the adjacent top and bottom walls such that spaces for flow of a heat exchange fluid are defined between adjacent ones of said side walls;    wherein each of the top walls of the heat exchange element extends between a pair of longitudinal bends through which it is joined to adjacent ones of said side walls, and wherein each of the bottom walls of the heat exchange element extends between a pair of longitudinal bends through which it is joined to adjacent ones of said side walls;    wherein protrusions are provided in at least some of the top walls and at least some of the bottom walls of the heat exchange element; and    wherein each of the protrusions in the top walls cause portions of said top walls to deviate away from the top plane of the heat exchange element in a direction toward the bottom plane of the heat exchange element, and wherein the protrusions in the bottom walls cause portions of said bottom walls to deviate away from the bottom plane of the heat exchange element in a direction toward the top plane of the heat exchange element.