Firetube heat exchanger

Abstract

A firetube having an elongated cylindrical shell is characterized by a plurality of circular rows of elongated U-shaped fins, each having a bottom surface, preferably curved along a radius or flat, secured to the inner surface of the cylindrical shell and two flat, planar, preferably parallel sides extending upwardly from the bottom surface, with the fins in each row aligned substantially parallel along the axis of the cylindrical shell.

1 . A firetube heat exchanger comprising:
 an elongated cylindrical shell having an inlet end and an outlet end; and   a fin assembly secured on the inner surface of said shell, said fin assembly comprising a plurality of circular rows of elongated U-shaped fins, each fin having a bottom surface secured to the inner surface of said cylindrical shell and two flat, planar sides extending upwardly from said bottom surface and defining an elongated interior channel,   wherein said fins in each row are aligned substantially parallel along the axis of said cylindrical shell.   
     
     
         2 . A firetube heat exchanger of  claim 1  wherein the bottom surface of each of said fins comprises a generally flat, planar surface. 
     
     
         3 . A firetube heat exchanger of  claim 1  wherein the bottom surface of said fins is curved on a radius. 
     
     
         4 . A firetube heat exchanger of  claim 1  wherein the fins in each row of fins, respectively, are substantially identical. 
     
     
         5 . A firetube heat exchanger of  claim 1  wherein the height of the fins in the first row of fins adjacent to the inlet are lower than the height of fins in other rows of fins. 
     
     
         6 . A firetube heat exchanger of  claim 5  comprising three or more rows of fins and wherein the height of fins in the second row of fins from the inlet end are higher than the fins of said first row of fins and lower than the height of fins of one or more successive rows of fins. 
     
     
         7 . A firetube heat exchanger of  claim 5  comprising between 2 and 20 rows of fins. 
     
     
         8 . A firetube heat exchanger of  claim 5  comprising between 4 and 12 rows of fins. 
     
     
         9 . A firetube heat exchanger of  claim 6  comprising between 4 and 12 rows of fins. 
     
     
         10 . A firetube heat exchanger of  claim 1  wherein fins of one or more rows of fins are offset angularly from the fins of an adjacent row of fins. 
     
     
         11 . A firetube heat exchanger of  claim 1  wherein the height of the sides of all fins in a row of fins are equal. 
     
     
         12 . A firetube heat exchanger of  claim 1  wherein the width of all fins in a row of fins are equal. 
     
     
         13 . A firetube heat exchanger of  claim 1  wherein the width of all fins are equal. 
     
     
         14 . A firetube heat exchanger of  claim 11  wherein the width of all fins are equal. 
     
     
         15 . A firetube heat exchanger of  claim 10  wherein the height of the sides of all fins in a row of fins are equal. 
     
     
         16 . A firetube heat exchanger of  claim 10  wherein the width of all fins in a row of fins are equal. 
     
     
         17 . A firetube heat exchanger of  claim 10  wherein the width of all fins are equal. 
     
     
         18 . A firetube heat exchanger of  claim 13  wherein the fins of adjacent rows of fins are offset angularly up to one-half of the fin width. 
     
     
         19 . A firetube heat exchanger of  claim 18  wherein the height of the sides of all fins in a row of fins are equal. 
     
     
         20 . A firetube heat exchanger of  claim 18  wherein the height of the fins in the first row of fins adjacent to the fluid inlet are lower than the height of fins in other rows of fins. 
     
     
         21 . A firetube heat exchanger of  claim 20  wherein the height of the sides of all fins in a row of fins are equal. 
     
     
         22 . A firetube heat exchanger of  claim 1  wherein the length of all fins in a row of fins are equal. 
     
     
         23 . A firetube heat exchanger of  claim 1  wherein the length of all fins in a row are equal and the lengths of fins in two or more different rows are different. 
     
     
         24 . A firetube heat exchanger of  claim 1  wherein the length of all fins are equal. 
     
     
         25 . A firetube heat exchanger of  claim 24  wherein the height of the sides of all fins in a row of fins are equal. 
     
     
         26 . A firetube heat exchanger of  claim 24  wherein the width of all fins in a row of fins are equal. 
     
     
         27 . A firetube heat exchanger of  claim 24  wherein the width of all fins are equal. 
     
     
         28 . A firetube heat exchanger of  claim 24  wherein the fins of adjacent rows of fins are offset angularly up to one-half of the fin width. 
     
     
         29 . A firetube heat exchanger of  claim 24  wherein the height of the sides of all fins in a row of fins are equal. 
     
     
         30 . A firetube heat exchanger of  claim 24  wherein the height of the fins in the first row of fins adjacent to the fluid inlet are lower than the height of fins in other rows of fins. 
     
     
         31 . A firetube heat exchanger of  claim 4  wherein the height of the fins in the first row of fins adjacent to the fluid inlet are lower than the height of fins in other rows of fins. 
     
     
         32 . A firetube heat exchanger of  claim 31  comprising between 4 and 20 rows of fins and wherein the height of fins of row 3 and subsequent rows of fins are equal. 
     
     
         33 . A firetube heat exchanger of  claim 32  wherein fins of one or more rows of fins are offset angularly from the fins of an adjacent row of fins. 
     
     
         34 . A firetube heat exchanger of  claim 32  wherein the fins of adjacent rows of fins are offset angularly up to one-half of the fin width. 
     
     
         35 . A firetube heat exchanger of  claim 1  wherein the two sides of each of said fins are substantially parallel. 
     
     
         36 . A firetube heat exchanger of  claim 2  wherein the two sides of each of said fins are substantially parallel and perpendicular to the bottom surface. 
     
     
         37 . A firetube heat exchanger of  claim 2  wherein the two sides of each of said fins extend upwardly from said bottom surface at acute angles or obtuse angles. 
     
     
         38 . A firetube heat exchanger of  claim 3  wherein the two sides of each of said fins are substantially parallel. 
     
     
         39 . A firetube heat exchanger of  claim 3  wherein the two sides of each of said fins extend upwardly from said bottom surface at acute angles or obtuse angles. 
     
     
         40 . A firetube heat exchanger of  claim 1  further comprising a heat resistant insert positioned concentrically along a portion of the length of said interior channel. 
     
     
         41 . A firetube heat exchanger of  claim 1  further comprising a plurality of brazed thermally conductive rings forming a conductive and ductile bond between the inner surface of said cylindrical shell and adjacent rows of said fins. 
     
     
         42 . A firetube heat exchanger of  claim 41  comprising a said brazed thermally conductive ring between all adjacent rows of said fins. 
     
     
         43 . A firetube heat exchanger of  claim 41  comprising one or more brazed thermally conductive rings along the inner surface of said cylindrical shell between the last row of fins and said fluid outlet end. 
     
     
         44 . A firetube heat exchanger comprising:
 an elongated shell having an inlet end and an outlet end; and   a fin assembly secured on the inner surface of said shell, said fin assembly comprising a first and second row of U-shaped elongated fins, each fin having at least one planar side extending upwardly from said inner surface and defining an elongated interior channel,   wherein said first row of fins is adjacent said inlet end and wherein said second row of fins is taller than said first row of fins.   
     
     
         45 . A firetube heat exchanger of  claim 44 , wherein each row of elongated fins are aligned substantially parallel along a central axis of said cylindrical shell.