Heat exchanger with dimpled tube surfaces

Abstract

A heat exchanger including a shell having an inner chamber defined by an inside wall surface, and a tube stack disposed within the inner chamber. The shell is formed of a single piece of material. The tube stack includes a plurality of flat elongated tubes arranged in a stack. Each of the tubes is formed of a single piece of material that is joined along a seam. A first fluid flow path is defined within the tubes. The tubes each include a plurality of projections projecting outwardly therefrom. The projections on adjacent tubes contact one another, thereby forming a second fluid flow path.

1 . A heat exchanger comprising: 
 a shell having an inner chamber defined by an inside wall surface; and    a tube stack disposed within the inner chamber and comprising a plurality of tubes arranged in a stack, wherein the tubes are formed from a single piece of material, wherein a first gas or fluid flow path is defined within the tubes, wherein the tubes each include a plurality of projections extending outwardly from an outer surface, and wherein projections on each tube contact an adjacent tube so as to form a second gas or fluid flow path between and across the outer surfaces of adjacent tubes.    
   
   
       2 . The heat exchanger as recited in  claim 1  wherein the projections on a first tube contact projections on an adjacent to so as the create a space between the tubes, the height of said space being approximately the combined height of the contacting projections.  
   
   
       3 . The heat exchanger as recited in  claim 2  wherein the projections of adjacent tubes are bonded together.  
   
   
       4 . The heat exchanger as recited in  claim 1  wherein the shell has a one-piece construction made from a single piece of material.  
   
   
       5 . The heat exchanger as recited in  claim 1  wherein the projections are arranged along each tube outer surface such that the second fluid flow path is non linear.  
   
   
       6 . The heat exchanger as recited in  claim 1  further comprising a flow element disposed within at least one of the tubes that creates more than one first gas or fluid flow path within the tube.  
   
   
       7 . The heat exchanger as recited in  claim 1  wherein the projections extend a distance from the tube outer surface in the range of from about 0.5 mm to 2 mm.  
   
   
       8 . The heat exchanger as recited in  claim 1  further comprising a header plate attached to the tubes and positioned adjacent an end of the tube stack, the header plate being interposed between the tube stack and the an inside wall surface of the shell.  
   
   
       9 . The heat exchanger as recited in  claim 1  wherein the tubes are shaped having a rectangular cross section, and wherein the tubes include a single seam that extends lengthwise between opposed open tube ends.  
   
   
       10 . A method of making a heat exchanger comprising the steps of 
 assembling a plurality of tubes into a stacked arrangement to form a tube stack, wherein each tube is one-piece construction formed from a single piece of material, and wherein each tube includes an outer surface that comprises a plurality of projections that extend outwardly therefrom, wherein the projections on each tube in the stack contact an adjacent tube so as to form a fluid flow passage between and along outside surfaces of adjacent tubes, and wherein the tubes are secured within the tube stack by a header plate at opposed tube ends;    inserting the tube stack into a shell, wherein the header plate is interposed between the shell and assembly of tubes; and    sealing one or more ends of the shell to encase the tube stack therein, and to form a leak tight seal between gas or fluid flowing through the tube stack, and gas or fluid flowing between the tube stack and the shell.    
   
   
       11 . The method as recited in to the  claim 10  further comprising before the step of inserting, bonding the projections of adjacent tubes.  
   
   
       12 . The method as recited in  claim 11  further comprising, forming the shell from a single piece of material to form a one-piece construction.  
   
   
       13 . The method as recited in  claim 10  further comprising before the step of inserting, forming the projections in a pattern such that the gas or fluid flow passage is non linear.  
   
   
       14 . The method as recited in  claim 10  further comprising before the step of inserting, forming the projections, wherein the projections extend a distance from the tube outer surface in the range of from about 0.5 mm to 2 mm.  
   
   
       15 . The method as recited in  claim 10  further comprising, before the step of assembling, forming the tubes from a single piece of material that is joined together along a single lengthwise edge.  
   
   
       16 . The heat exchanger as recited in  claim 10  wherein the projections on a first tube contact projections on an adjacent so that the height of the space created between the adjacent tubes is approximately the combined height of the contacting projections.