Multipass tubular heat exchanger and associated pass partition plate, channel cover, and methods

Abstract

A multipass tubular heat exchanger utilizing a pass partition plate and a tubesheet is described which is suitable for use with high differential pressure tubeside fluid without deformation or dislocation of the pass partition plate, thereby avoiding the problem of tubeside fluid bypassing. The pass partition plate has an edge fitting into a corresponding groove in the tubesheet. The edge and the corresponding groove each have a radius of curvature about an axis extending generally perpendicular to the tubesheet.

1 . A multipass tubular heat exchanger comprising:
 a plurality of tubes configured to contain a tubeside fluid, the plurality of tubes having at least one set of terminal ends;   a planar tubesheet comprising a plurality of apertures for receiving the ends of the tubes;   a channel having a tubeside fluid inlet and a tubeside fluid outlet, the channel positioned adjacent the tubesheet such that the channel and tubesheet together define an internal space in fluid communication with the tubes; and   
       a nonplanar pass partition plate positioned in the internal space configured to divide the internal space into an inlet space in fluid communication with the tubeside fluid inlet and an outlet space in fluid communication with the tubeside fluid outlet, thereby to prevent direct fluid communication between the tubeside fluid inlet and the tubeside fluid outlet and to direct fluid flow through the tubes; 
       wherein the pass partition plate has an edge which is fixed to the tubesheet, the edge having a radius of curvature about an axis extending generally perpendicular to the tubesheet. 
     
     
         2 . The multipass tubular heat exchanger of  claim 1  wherein the planar tubesheet further comprises
 a groove for receiving the pass partition plate, the groove having a length, a thickness, two endpoints and a midpoint;
 and wherein the pass partition plate further comprises a mating edge which fits into the groove of the tubesheet; 
 wherein the groove of the tubesheet and the mating edge of the pass partition plate each have a radius of curvature about an axis extending generally perpendicular to the tubesheet such that the midpoint of the groove is a greater distance from a straight line passing through the endpoints of the groove than the thickness of the groove. 
 
 
     
     
         3 . The multipass tubular heat exchanger of  claim 1  further comprising:
 a shell enclosing the plurality of tubes for containing a shell fluid, the shell having a first end and a second end and having a shell fluid inlet and a shell fluid outlet; 
 wherein the tubesheet is secured to the first end of the shell. 
 
     
     
         4 . The multipass tubular heat exchanger of  claim 1  further comprising a gasket between the channel and the tubesheet. 
     
     
         5 . The multipass tubular heat exchanger of  claim 4  wherein the gasket includes a rib portion adjacent and between the pass partition plate and the groove of the tubesheet. 
     
     
         6 . The multipass tubular heat exchanger of  claim 1  wherein the midpoint of the groove is a greater distance from a straight line passing through the endpoints of the groove than the distance between the endpoints of the groove divided by 100. 
     
     
         7 . The multipass tubular heat exchanger of  claim 1  wherein the heat exchanger is an air cooled heat exchanger in which heat is exchanged between the tubeside fluid within the plurality of tubes and air moving over the plurality of tubes. 
     
     
         8 . The multipass tubular heat exchanger of  claim 1  wherein the plurality of tubes comprise straight tubes having openings on each end received by apertures in a tubesheet on each end in fluid communication with a channel on each end adjacent the tubesheet. 
     
     
         9 . The multipass tubular exchanger of  claim 1  wherein the plurality of tubes comprise U-shaped tubes. 
     
     
         10 . The multipass tubular heat exchanger of  claim 1  comprising multiple pass partition plates. 
     
     
         11 . The multipass tubular heat exchanger of  claim 1  comprising multiple grooves. 
     
     
         12 . The multipass tubular heat exchanger of  claim 1  wherein the radius of curvature is in the direction of the tubeside fluid inlet. 
     
     
         13 . The multipass tubular heat exchanger of  claim 1  wherein the radius of curvature is in the direction of the tubeside fluid outlet. 
     
     
         14 . A matching pass partition plate and tubesheet for use in a multipass tubular heat exchanger comprising:
 a planar tubesheet comprising apertures for receiving ends of heat exchanger tubes and a groove for receiving a pass partition plate, the groove having a length, a thickness, two endpoints and a midpoint;   a nonplanar pass partition plate having a mating edge which fits into the groove of the tubesheet;   wherein the groove of the tubesheet and the mating edge of the pass partition plate each have a radius of curvature about an axis extending generally perpendicular to the tubesheet such that the midpoint of the groove is a greater distance from a straight line passing through the endpoints of the groove than the thickness of the groove.   
     
     
         15 . A channel cover for use in a multipass tubular heat exchanger comprising:
 a semi-enclosed channel having a planar open end and configured to define an internal space when the open end is positioned adjacent a planar tubesheet; and   a nonplanar pass partition plate having peripheral edges fixed within the channel and a free edge in the plane of the open end wherein the free edge has a radius of curvature about an axis extending generally perpendicular to the plane of the open end.   
     
     
         16 . A method of retrofitting a multipass tubular heat exchanger having an existing tubesheet and an existing pass partition plate, comprising:
 removing the existing tubesheet and the existing pass partition plate;   installing a planar tubesheet comprising a plurality of apertures for receiving ends of heat exchanger tubes and a groove for receiving a pass partition plate; and   a nonplanar pass partition plate having a mating edge which fits into the groove of the tubesheet;   wherein the groove of the tubesheet and the mating edge of the pass partition plate each have a radius of curvature about an axis extending generally perpendicular to the tubesheet.   
     
     
         17 . A method of exchanging heat between a tubeside fluid flowing through a plurality of tubes in a multipass tubular heat exchanger and a fluid surrounding the plurality of tubes, comprising:
 introducing a tubeside fluid into an internal space defined by a channel and a planar tubesheet having a plurality of apertures, the internal space being in fluid communication with a plurality of tubes having a plurality of a tubeside fluid inlet ends aligned with a first portion of the plurality of apertures of the tubesheet and a plurality of tubeside fluid outlet ends aligned with a second portion of the plurality of apertures of the tubesheet; and   flowing the tubeside fluid into the plurality of tubes through the first portion of the plurality of apertures and through the plurality of tubes between the tubeside fluid inlet ends and the tubeside fluid outlet ends such that the tubeside fluid exits through the second portion of the plurality of apertures into the internal space;   wherein the tubeside fluid exiting the tubes is separated from the tubeside fluid entering the tubes by a nonplanar pass partition plate dividing the internal space having an edge in contact with the tubesheet which has a radius of curvature about an axis perpendicular to the tubesheet;   wherein no bypassing of tubeside fluid occurs around the pass partition plate.