Tube configuration for a heat exchanger, heat exchanger including the tube configuration, fluid heating system including the same, and methods of manufacture thereof

Abstract

A heat exchanger tube assembly comprising a first tube sheet, a second tube sheet opposite the first sheet, a plurality of heat exchanger tubes, each independently connects the first tube sheet and the second tube sheet, wherein the tubes are in a staggered ring configuration that comprises a concentric sequence of rings of decreasing diameter wherein adjacent tubes on the same ring are separated by a fixed radial separation angle and adjacent tubes on adjacent rings are staggered by rotating all the tubes within an inner ring by a fixed radial index angle, IA, relative to the next outermost tube ring.

What is claimed is: 
     
         1 . A heat exchanger tube assembly comprising:
 a first tube sheet;   a second tube sheet opposite the first sheet;   a plurality of heat exchanger tubes, wherein each heat exchanger tube of the plurality of heat exchanger tubes independently connects the first tube sheet and the second tube sheet, and wherein the heat exchanger tubes are in a staggered ring configuration that comprises a plurality of concentric rings of tubes,   wherein adjacent tubes on a ring are separated by a radial separation angle RA.   
     
     
         2 . The heat exchanger tube assembly of  claim 1 , wherein the radial separation angle is 1 to 90 degrees. 
     
     
         3 . The heat exchanger tube assembly of  claim 1 , wherein neighboring tubes on adjacent rings are separated by rotating all the tubes within an inner ring by a radial index angle, IA, relative to the next outermost tube ring. 
     
     
         4 . The heat exchanger tube assembly of  claim 1 , further comprising a baffle located between the first tube sheet and the second tube sheets, wherein the plurality of heat exchanger tubes traverses through the baffle. 
     
     
         5 . The heat exchanger tube assembly of  claim 4 , wherein the baffle comprises at least one plate baffle; wherein fluid communication between a first side and a second side of the plate baffle is across a perimeter of the plate baffle. 
     
     
         6 . The heat exchanger tube assembly of  claim 4 , wherein the baffle comprises at least one annular baffle; wherein fluid communication between a first side and a second side of the annular baffle is through the annulus of the baffle. 
     
     
         7 . The heat exchanger tube assembly of  claim 4 , wherein the baffle comprises at least two plate baffles and at least two annular baffles; wherein a fluid flow traverses an alternating path of plate baffles and annular baffles. 
     
     
         8 . The heat exchanger tube assembly of  claim 4 , wherein neighboring tubes on adjacent rings are separated by rotating all the tubes within an inner ring by a radial index angle, IA, relative to the next outermost tube ring. 
     
     
         9 . A heat exchanger comprising:
 a pressure vessel; and   the heat exchanger tube assembly of  claim 1 ; wherein the heat exchanger tube assembly is disposed in the pressure vessel.   
     
     
         10 . The heat exchanger of  claim 9 , wherein neighboring tubes on adjacent rings are separated by rotating all the tubes within an inner ring by a radial index angle, IA, relative to the next outermost tube ring. 
     
     
         11 . A fluid heating system comprising:
 the heat exchanger of  claim 9 ;   wherein the pressure vessel comprises a pressure vessel shell comprising a first inlet and first outlet, a shell, a first top head and a first bottom head, wherein the shell is disposed between the first top head and the first bottom head, and wherein the first inlet and the first outlet are each independently on the shell, the first top head, or the first bottom head;   a conduit, which penetrates the pressure vessel shell, wherein a first end of the conduit is connected to the first tube sheet wherein the conduit is in fluid communication with the heat exchanger tubes and wherein a second end of the conduit is on the outside of the pressure vessel shell;   a burner disposed in the conduit; and   a blower, which is in fluid communication with the second end of the conduit.   
     
     
         12 . The heat exchanger tube assembly of  claim 11 , wherein neighboring tubes on adjacent rings are separated by rotating all the tubes within an inner ring by a radial index angle, IA, relative to the next outermost tube ring. 
     
     
         13 . A method of calculating the radial separation angle RA, and the radial stagger index angle IA, for a staggered ring heat exchanger tube configuration, using the design diameter DD of the tube configuration, a gap GAP between the design diameter and the first tube ring, the tube element clearance diameter CD k  for each row k of tubes, and the rounding threshold RT to be applied to the tube count, the method comprising:
 computing a diameter of an outer row RD 1  using the Formula 1
   RD 1 =DD−(2×GAP)−CD 1 ;  (1)
 
   computing the diameter RD k  of the interior rows 2≦k using the Formula 2
   RD k =RD k-1 −CD k-1 −CD k   (2)
 
   for each row diameter where RD k ≧0;   computing the tube count for each row k using Formula 3
   CT k =360/2 sin −1 (CD k /RD k );  (3)
 
   computing the integer tube count by rounding using the rounding threshold RT, where RT is between 0.001 and 0.99, wherein:   if the fractional part of the computed tube count CT k  is greater than the rounding threshold RT, round the tube count using Formula 4
     C   k =ceil(CT k ),  (4), and
 
   compute the final ring diameter using Formula 5
     D   k =CD k /sin(360/2 C   k );  (5)
 
   otherwise round the tube count using Formula 6
     C   k =floor(CT k ), and  (6)
 
   compute the final ring diameter using Formula 7
     D   1 =OD−(2×GAP)−CD 1   (8)
 
   if the computation is for the first row or Formula 9
     D   k   =D   k-1 −CD k-1 −CD k   (9)
 
   if for an inner row with k>1;   computing the fixed row separation angle RA k  for tubes in each row from k=1 to the innermost row using Formula 10
   RA k =360 /C   k ;  (10)
 
   computing the fixed tube stagger index angle IA k  for adjacent tubes in adjacent rows, k and k−1, using Formula 11
   IA k =(RA k +RA k-1 )/2  (11)
 
   for each inner row and setting IA 1 =0 for the first row, k=1.   
     
     
         14 . A heat exchanger tube assembly comprising:
 a first tube sheet;   a second tube sheet opposite the first sheet;   a plurality of heat exchanger tubes, wherein each heat exchanger tube of the plurality of heat exchanger tubes independently connects the first tube sheet and the second tube sheet, and wherein
 the heat exchanger tubes are in a staggered ring configuration that comprises a plurality of concentric rings of tubes, 
 the heat exchange tubes in each ring have approximately the same tube diameter and ligament; 
 the radial distance separating two adjacent rings is between one half and three times the sum of the minimum ligament and minimum tube diameter for any tube on the two adjacent rings; 
   wherein adjacent tubes on a ring are separated by a radial separation angle between 0.5 degrees and 180 degrees; and   each concentric ring contains a designated first tube.