Shell-and-tube heat exchanger assembly and method forlimiting a corrosion response of tubes therein

Abstract

A shell-and-tube heat exchanger assembly including a first tube sheet, a second tube sheet, and a plenum, is disclosed. The first tube sheet is adapted to be secured to a shell of the shell-and-tube heat exchanger assembly. The first tube sheet includes a plurality of first holes adapted to support a plurality of tubes extending through the shell. The second tube sheet is adapted to be fastened to a front surface of the first tube sheet and fastened to a rear surface of the plenum. The second tube sheet includes a plurality of second holes adapted to support the plurality of tubes extending through the plurality of first holes. The second tube sheet is made of a metal adapted to limit a corrosion response of the plurality of tubes when exposed to a chiller fluid.

What is claimed is: 
     
         1 . A shell-and-tube heat exchanger assembly comprising:
 a first tube sheet adapted to be secured to a shell of the shell-and-tube heat exchanger assembly, the first tube sheet comprising:
 a plurality of first holes adapted to support a plurality of tubes extending through the shell; and 
   a second tube sheet adapted to be fastened to a front surface of the first tube sheet and fastened to a rear surface of a plenum, the second tube sheet comprising:
 a plurality of second holes adapted to support the plurality of tubes extending through the plurality of first holes, 
   wherein the second tube sheet is made of a metal adapted to limit a corrosion response of the plurality of tubes when exposed to a chiller fluid.   
     
     
         2 . The shell-and-tube heat exchanger assembly of  claim 1 , wherein an electrochemical potential of the metal of the second tube sheet is equivalent or lower than an electrochemical potential of the material of the plurality of tubes. 
     
     
         3 . The shell-and-tube heat exchanger assembly of  claim 1 , wherein the second tube sheet is made of at least one of an aluminum alloy and an inert material. 
     
     
         4 . The shell-and-tube heat exchanger assembly of  claim 1 , wherein each of the plurality of tubes is made of an aluminum alloy. 
     
     
         5 . The shell-and-tube heat exchanger assembly of  claim 1 , wherein the plurality of first holes of the first tube sheet is aligned with the plurality of second holes of the second tube sheet. 
     
     
         6 . The shell-and-tube heat exchanger assembly of  claim 1 , wherein a plurality of first openings is defined in the first tube sheet, a plurality of second openings is defined in the second tube sheet, and a plurality of third openings is defined in the plenum. 
     
     
         7 . The shell-and-tube heat exchanger assembly of  claim 1 , wherein each of the plurality of first openings defined in the first tube sheet are aligned with a corresponding second opening from the plurality of second openings defined in the second tube sheet and a corresponding third opening from the plurality of third openings defined in the plenum. 
     
     
         8 . The shell-and-tube heat exchanger assembly of  claim 1 , wherein a plurality of fasteners are adapted to be inserted into aligned plurality of first openings, a plurality of second openings, and a plurality of third openings to fasten the second tube sheet to a front surface of the first tube sheet and fasten the second tube sheet to the rear surface of the plenum. 
     
     
         9 . The shell-and-tube heat exchanger assembly of  claim 8 , wherein the plurality of fasteners comprise at least one of a guiding pin, a screw thread fastener, and a bolt fastener. 
     
     
         10 . The shell-and-tube heat exchanger assembly of  claim 1 , wherein a sealing element is disposed in each of the plurality of first holes between the plurality of tubes extending through the shell and the first tube sheet. 
     
     
         11 . The shell-and-tube heat exchanger assembly of  claim 1 , wherein the chiller fluid inside each of the plurality of tubes is water. 
     
     
         12 . A method for limiting a corrosion response of a plurality of tubes of a shell-and-tube heat exchanger assembly, the method comprising:
 securing a first tube sheet to a shell of the shell-and-tube heat exchanger assembly;   disposing a second tube sheet between the first tube sheet and a plenum of the shell-and-tube heat exchanger assembly,   wherein the second tube sheet is fastened to a front surface of the first tube sheet and a rear surface of the plenum,   wherein the second tube sheet is made of a metal adapted to limit a corrosion response of the plurality of tubes when exposed to a chiller fluid.   
     
     
         13 . The method of  claim 12 , wherein an electrochemical potential of the metal of the second tube sheet is equivalent or lower than an electrochemical potential of the material of the plurality of tubes. 
     
     
         14 . The method of  claim 12 , wherein the second tube sheet is made of at least one of an aluminum alloy and an inert material. 
     
     
         15 . The method of  claim 12 , wherein the second tube sheet is fastened to the front surface of the first tube sheet and the rear surface of the plenum using at least one of fasteners and industrial adhesives. 
     
     
         16 . The method of  claim 12 , wherein the step of fastening the second tube sheet to the front surface of the first tube sheet and the rear surface of the plenum further comprises:
 aligning each of a plurality of first openings defined in the first tube sheet with a corresponding second opening from a plurality of second openings defined in the second tube sheet;   aligning each of the plurality of second openings with a corresponding third opening from a plurality of third openings defined in the plenum; and   inserting a plurality of fasteners into the aligned plurality of first openings, the plurality of second openings, and the plurality of third openings to fasten the second tube sheet to the front surface of the first tube sheet and fasten the second tube sheet to the rear surface of the plenum.