Concentric tube heat exchanger and end seal therefor

Abstract

A concentric tube heat exchanger comprises an outer tube and a concentric inner tube, with an annular passageway between the tubes. The ends of the annular passageway are sealed by sealing members having axially extending inner and outer walls which are connected to one another and which are sealed to the respective outer and inner tubes. The sealing member walls are preferably connected by an integrally formed connecting wall. The walls of the sealing member are preferably resilient and diverge so as to form a friction fit with the tubes during assembly of the heat exchanger. The heat exchanger further comprises a turbulizer which comprises a plurality of rows of corrugations defining axially extending flow passages. Preferably, the corrugations have a top land width greater than a bottom land width so that the side walls of the corrugation are radially arranged in the annular passageway. Adjacent corrugations in each row are preferably offset relative to one another by an amount of from about 30 percent to about 40 percent.

1 . A concentric tube heat exchanger having a first end and a second end, the heat exchanger comprising: 
 (a) an outer tube;    (b) an inner tube received inside the outer tube and concentric therewith, wherein an annular passageway is formed between the inner and outer tubes;    (c) first and second annular sealing members received inside the annular passageway between the inner and outer tubes, the first sealing member being positioned proximate the first end of the heat exchanger and the second sealing member being positioned proximate the second end of the heat exchanger, each of the sealing members comprising an outer wall and an inner wall which are connected to one another, each of the walls having first and second axially-spaced ends, the outer wall being sealed to the outer tube and the inner wall being sealed to the inner tube, thereby sealing the ends of the tubes.    
   
   
       2 . The concentric tube heat exchanger of  claim 1 , wherein each of the sealing member walls has an axially-extending portion between its first and second end.  
   
   
       3 . The concentric tube heat exchanger of  claim 1 , wherein the inner and outer walls of the sealing members are connected through a connecting portion which seals a radial space between the sealing member walls.  
   
   
       4 . The concentric tube heat exchanger of  claim 3;  wherein the sealing members are generally U-shaped, with the first ends of the sealing member walls being connected to the connecting portion and the second ends of the sealing member walls being distal to the connecting portion.  
   
   
       5 . The concentric tube heat exchanger of  claim 1 , wherein the sealing members are spaced inward from the ends of the heat exchanger, such that the second ends of the sealing member walls are proximate to, and spaced inwardly from, the ends of the heat exchanger.  
   
   
       6 . The concentric tube heat exchanger of  claim 5 , wherein the sealing members are brazed to the tubes such that fillets of filler metal are formed between the tubes and the ends of the sealing member walls, and wherein the sealing members are spaced inwardly from the ends of the heat exchanger by a distance sufficient that the fillets between the second ends of the sealing member walls and the tubes are located inwardly of the ends of the heat exchanger.  
   
   
       7 . The concentric tube heat exchanger of  claim 3 , wherein the connecting portion is rounded.  
   
   
       8 . The concentric tube heat exchanger of  claim 3 , wherein the connecting portion is flat.  
   
   
       9 . The concentric tube heat exchanger of  claim 1 , wherein the tubes and the sealing members are comprised of aluminum.  
   
   
       10 . The concentric tube heat exchanger of  claim 9 , wherein the tubes are provided with a cladding comprised of a brazing alloy, at least on surfaces which are joined to the sealing members.  
   
   
       11 . The concentric tube heat exchanger of  claim 10 , wherein the sealing members are provided with a cladding comprised of a brazing alloy, at least one surfaces which are joined to the tubes.  
   
   
       12 . The concentric tube heat exchanger of  claim 1 , further comprising a turbulizer received in the annular passageway, the turbulizer comprising a plurality of corrugations defining a plurality of axially extending flow passages extending parallel to the tubes, each of the corrugations comprising a top land, a bottom land and a pair of side surfaces connecting the top and bottom lands, the top land being in heat exchange contact with the outer tube and the bottom land being in heat exchange contact with the inner tube; 
 wherein the convolutions are arranged in axially extending rows with the convolutions in each row being connected to one another and with an offset being provided between adjacent convolutions in each row, the offset having a width which is from about 30 percent to about 40 percent of a width of the top land or the bottom land.    
   
   
       13 . The concentric tube heat exchanger of  claim 12 , wherein the width of the offset is from about 31 percent to about 36 percent of the top land width or the bottom land width.  
   
   
       14 . The concentric tube heat exchanger of  claim 13 , wherein the width of the offset is about 31 percent of the top land width.  
   
   
       15 . The concentric tube heat exchanger of  claim 13 , wherein the width of the offset is about 36 percent of the bottom land width.  
   
   
       16 . The concentric tube heat exchanger of  claim 13 , wherein the top land width is greater than the bottom land width and wherein the side surfaces extend radially between the inner and outer tubes.  
   
   
       17 . The concentric tube heat exchanger of  claim 13 , wherein the tubes and the turbulizer are comprised of aluminum with the top land being brazed to the outer tube and the bottom land being brazed to the inner tube.  
   
   
       18 . A sealing member for sealing opposite ends of an annular passageway extending along an axis between inner and outer tubes of a concentric tube heat exchanger, the sealing member comprising: 
 an outer wall having first and second axially-spaced ends and having a generally axially-extending portion between its ends for sealing to the outer tube; and    an inner wall having first and second axially-spaced ends, the inner wall being connected to the outer wall and being spaced radially inwardly of the outer wall, the inner wall having a generally axially-extending portion between its ends for sealing to the inner tube;    wherein the generally axially-extending portions of the walls diverge from one another along said axis.    
   
   
       19 . The sealing member of  claim 18 , wherein the inner and outer walls are connected through a connecting portion, the second ends of the sealing member walls are axially spaced from the connecting portion, the generally axially-extending portions of the sealing member walls extend between the connecting portion and the second end, and wherein the generally axially-extending portions diverge from said connecting portion to the second ends of the sealing member walls.  
   
   
       20 . The sealing member of  claim 18 , wherein the generally axially-extending portions of the walls are resilient, and wherein the generally axially-extending portions diverge from one another at an angle such that, during assembly, the sealing members are slidably received in the annular passageway with the outer wall frictionally engaging the outer tube and the inner wall frictionally engaging the inner tube, and such that the generally axially-extending portions of the sealing member walls are in substantial engagement with the inner and outer tubes.  
   
   
       21 . The sealing member of  claim 18 , wherein the generally axially-extending portion of at least one of the sealing member walls diverges from the axis by an angle of from about 1 to about 2 degrees.