Optimized plate fin heat exchanger for improved compliance to improve thermal life

Abstract

A heat exchanger includes a hot passage; a cold passage adjacent the hot passage; a pair of tube sheets, with one tube sheet on each opposing side of one of the hot passage and the cold passage; a fin in one of the hot passage and the cold passage; wherein the fin includes a first distal portion, a second distal portion, and an intermediate portion between the first and second distal portions; wherein the fin is configured to provide, at only the first distal portion and the second distal portion, improved flexibility in three degrees of freedom of movement within one of the hot passage and the cold passage.

We claim: 
     
         1 . A heat exchanger, comprising
 a hot passage;   a cold passage adjacent the hot passage;   a pair of tube sheets, with one tube sheet on each opposing side of one of the hot passage and the cold passage;   a fin in one of the hot passage and the cold passage;   wherein the fin includes a first distal portion, a second distal portion, and an intermediate portion between the first and second distal portions;   wherein the fin is configured to provide, at only the first distal portion and the second distal portion, three degrees of freedom of movement within one of the hot passage and the cold passage.   
     
     
         2 . The heat exchanger of  claim 1 , further comprising a plurality of tube sheets, whereby any one tube sheet has two immediately adjacent tube sheets, whereby one tube sheet of the two immediately adjacent tube sheets is on each side of the any one tube sheet. 
     
     
         3 . The heat exchanger of  claim 1 , wherein the pair of tube sheets are on opposing sides of the cold passage, and the pair of tube sheets are not affixed to one another at certain locations. 
     
     
         4 . The heat exchanger of  claim 1 , wherein the fin has a sinusoidal configuration. 
     
     
         5 . The heat exchanger of  claim 1 , wherein one of the first distal portion and the second distal portion has a divided sinusoidal configuration. 
     
     
         6 . The heat exchanger of  claim 1 , wherein one of the first distal portion and the second distal portion is separated laterally through its cross section. 
     
     
         7 . The heat exchanger of  claim 1 , wherein the fin is laterally separated at its cross-sectional mid-point. 
     
     
         8 . A plate fin heat exchanger, comprising a hot passage;
 a cold passage adjacent the hot passage;   a pair of tube sheets on opposing sides of the cold passage;   a fin in the cold passage;   wherein the fin includes a first distal portion, a second distal portion, and an intermediate portion between the first and second distal portions;   wherein the fin, at only the first distal portion and the second distal portion, is separated laterally into a first lateral portion and a second lateral portion.   
     
     
         9 . The heat exchanger of  claim 8 , further comprising:
 a plurality of cold passages,   wherein the plurality of cold passages include outer cold passages, and   wherein the cold passage with the fin therein is one of the outer cold passages.   
     
     
         10 . The heat exchanger of  claim 9 , wherein the plurality of outer cold passages includes a distal area defined by an area having a length and height. 
     
     
         11 . The heat exchanger of  claim 10 , wherein a ratio of the length to the height is from about 0.5 to about 1.0. 
     
     
         12 . The heat exchanger of  claim 10 , further comprising a cold inlet face, and
 wherein a ratio of the height of the distal area to an overall height of the cold inlet face is from about 3% to about 11%.   
     
     
         13 . The heat exchanger of  claim 9 , wherein the plurality of outer cold passages includes from about 4 to about 8 cold passages. 
     
     
         14 . The heat exchanger of  claim 8 , wherein:
 the cold passage includes a cold passage distal portion located at a corner where the cold passage meets the hot passage, and   one of the first and second distal portions of the fin is located at the cold passage distal portion.   
     
     
         15 . A plate fin heat exchanger, comprising
 a plurality of cold passages;   a plurality of fins in the cold passages;   a plurality of hot passages;   a plurality of tube sheets;   wherein the cold passages, hot passages and tube sheets are positioned in an recurring pattern of cold passage, tube sheet, hot passage, and tube sheet;   wherein one of the plurality of fins has a distal portion with a divided configuration to provide three degrees of freedom of movement of the fin at the distal portion.   
     
     
         16 . The heat exchanger of  claim 15 , wherein the divided configuration is a lateral separation through a cross section of the distal portion. 
     
     
         17 . The heat exchanger of  claim 16 , wherein the lateral separation is at a mid-point of the cross section. 
     
     
         18 . The heat exchanger of  claim 16 , wherein the lateral separation is less than an entire distance between a cold inlet face and a cold outlet face.