US3626481A

US3626481A - Heat exchangers

Info

Publication number: US3626481A
Application number: US3961A
Authority: US
Inventors: Derek Taylor; Reginald Philip Hardingham
Original assignee: UK Atomic Energy Authority
Current assignee: UK Atomic Energy Authority
Priority date: 1969-01-28
Filing date: 1970-01-19
Publication date: 1971-12-07
Anticipated expiration: 1988-12-07
Also published as: SE359372B; DE2003197A1; GB1280662A; FR2029574A1; DE7002412U; FR2029574B1; ES375961A1

Abstract

A grid for locating the tubes of a heat exchanger in which the tubes are arranged parallel to one another in rows. The tubes are located by support members of zigzag strip material carried on structural components extending between the rows of tubes. In a particular arrangement the tubes are in concentric rows and the structural components carrying the zigzag support members are in the form of annular strips extending between alternate rows of the tubes the rows of tubes on either side of the annular strips being supported by zigzag support members attached to each side of the annular strips.

Description

United States Patent Inventors Appl. No. Filed Patented Assignee Priority HEAT EXCHANGERS 7 Claims, 7 Drawing Figs. 7

U.S. Cl 165/162 Int. Cl F2311 7/00 Field of Search. 165/69, 162

References Cited UNITED STATES PATENTS 6/1964 Sprague et al. 165/ l6 2 3T39 7 t""8/1967 Bernsteinetal. 165/162 FOREIGN PATENTS 1,017,455 1/1966 GreatBritain 165/162 Primary Examiner-Carroll Bv Dority, .lr. An0meyLarson, Taylor and Hinds ABSTRACT: A grid for locating the tubes of a heat exchanger in which the tubes are arranged parallel to one another in rows. The tubes are located by support members of zigzag strip material carried on structural components extending between the rows of tubes. In a particular arrangement the tubes are in concentric rows and the structural components carrying the zigzag support members are in the form of annular strips extending between alternate rows of the tubes the rows of tubes on either side of the annular strips being supported by zigzag support members attached to each side of the annular strips.

PATENTEDBEC new 3626L481 SHEET 1 [IF 3 PATENTED um 71971 sum 3 UF 3 BACKGROUND OF THE INVENTION This invention relates to heat exchangers, and in particular to that kind of heat exchanger in which an array of tubes is arranged in a container (often termed a tube-in-shell' type of heat exchanger), one heat exchange fluid flowing in contract with the exterior of the tubes and another heat exchanger fluid flowing within the tubes. In this kind of heat exchanger, it is generally necessary to provide some lateral support for the tubes to prevent tube vibration and also to ensure that the spacing therebetween is maintained, otherwise flow of the external fluid may be impeded and hot spots may develop if the tubes become deformed laterally sufficiently to approach or touch one another.

SUMMARY OF THE INVENTION According to the invention a heat exchanger in which a parallel array of heat exchanger tubes is arranged in a container includes a support structure for maintaining correct lateral spacing of the tubes, said support structure comprising a structural framework having components extending laterally through the spaces between the tubes and support members for the tubes mounted on the components of the structural framework, said support members being adapted to provide lateral support for rows of the heat exchange tubes, the support members comprising strip material bent in the form of a zigzag so that adjacent flanks of the zigzag strip material are adapted to contact and provide lateral location for the heat exchange tubes, the apexes of the zigzag strip material, at least on one side, comprising looped portions capable of being opened or closed so as to allow variation in the angle between the flanks of the zigzag strip material on either side of the looped portions to provide for adaptation of the zigzag strip material to conform with variations of pitch in the rows of heat exchanger tubes. Where the heat exchange tubes of the heat exchanger are longitudinally arranged parallel to one another in the container and are concentrically pitched said support structure for maintaining correct lateral spacing of the heat exchange tubes may comprise main radially extending components and radially spaced part annular strips connected at their ends to the radially extending components, the part annular strips being disposed so as to extend circumferentially through alternate spaces between the concentric rows of heat exchange tubes, a support member of zigzag strip material having truncated apexes along one side being secured at the truncated apexes to each side of each part annular strip, the non secured apexes of the support members of zigzag strip material comprising looped portions, the part annular strips of the structural framework and the support members of zigzag strip material being edge-on to axial flow of heat exchange fluid over the heat exchange tubes, adjacent flanks of the support members of zigzag strip material contacting and providing lateral location for the corresponding heat exchange tubes, the angle between the tube supporting adjacent flanks of the support member on the convex outer side of each part annular strip of the support structure being greater than the angle between the tube supporting adjacent flanks of the corresponding support member on the convex inner side of said part annular strip to allow for the pitch of the concentric row of heat exchange tubes on the outside of the part annular strip being greater than the pitch of the concentric row of heat exchange tubes on the inside of the part annular strip.

DESCRIPTION OF THE DRAWING An embodiment of the invention will now be described by way of example with reference to the accompanying drawings in which:

FIG. I is a fragmentary plan view of a quarter of a structure for maintaining correct lateral spacing of tubes in a heat exchanger, the other three quarters being similar,

FIG. 2 is an enlarged detached plan view and illustrates a detail of FIG. 1,

FIG. 3 illustrates the first stage in the fabrication of generally corrugated strip for the said structure,

FIG. 4 illustrates the second stage in said fabrication,

FIG. 5 illustrates generally the third stage in said fabricatron,

FIG. 6 illustrates one alternative for said third stage, and

FIG. 7 illustrates another alternative for said third stage.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring firstly to FIGS. 1 and 2 of the accompanying drawings, a heat exchanger of the tube-in-shell type has a cylindrical container 10 whose wall is shown in section in FIG. 1 and designated 11. There is also a concentric inner wall 12 providing a central passage 13 for heat exchange fluid to flow in one axial direction in the container 10 before reversing to flow over heat exchange tubes 14 in the annulus A between

walls

11 and 12. The tubes 14 are arranged in concentric annular rows, with the spacing between adjacent tubes in all rows kept constant. Taking the registering tubes of all the annular rows which are nearest to one radial end of the quarter of the heat exchanger shown in FIG. I (the tubes 14 designated R in FIG. l-these are parallel to truly radial), the remaining tubes 14 in that quarter do not form into radial rows; rather the remaining rows are generally parallel to the row of tubes R up to a region where the curvature of the annular rows distorts the pattern. At the commencement of the next quarter, the first row (tubes R) again is parallel to truly radial, as can be seen from FIG. 1, and so on.

Lateral location for the tubes 14 at each of the plurality of levels in the container 10 is provided by a structure 15 comprising an inner annular structural member (one quarter being shown in FIG. I designated 16), an outer annular structure member (one quarter being shown in FIG. I designated 17), radial structural members 18 (two being shown in FIG. 1) secured at their ends to the

members

16 and 17 respectively, and part-annular strips 19 disposed between alternate concentric rows of tubes 14 and secured at one of their ends to a radial structural member 18. The secured end of each strip 19 is welded to a triangular fillet 20 on the radial member 18; the other end is slotted into a fitting 21 on the succeeding radial member 18 which fitting 21 allows a measure of expansion and contraction.

Each part-annular strip 19 has the plane of its width parallel to the longitudinal axis of the container 10, that is, it is edgeon to axial flow of heat exchange fluid external to the tubes 14. On each side of each strip 19 there is provided a support member of strip material bent in the form of a zigzag which is curved to fit the curvature of its strip 19. That support member on the concave side of each strip 19 is designated generally 22, and that on the convex side of each strip 19 is designated generally 23.

The

support members

22, 23 are each bent in the following manner. Ordinary angle bends are transformed to five truncated apexes 24 at one side and apexes with looped portions 25 on the other side. This can be seen in FIG. 1 and more clearly in the enlarged view of FIG. 2. The straight truncated portions 24 are each welded to the part-annular strip 19, and the flanks of the angular portions 26 serve to engage the heat exchange tubes at what approximates to line contact at two spaced positions round each tube I4. The looped portions 25 lie between adjacent tubes 14, and are capable of being opened or closed as necessary, to allow a measure of flexibility in adapting each

support member

22, 23 to the pitch of the tubes 14, it being realized that due to the curvature of the strips 19, the annular length of the support member 23 on the convex side of the strip 19 will be shorter than that of the support member 22 on the concave side with the correct constant concentric spacing of the tubes 14 retained.

FIG. 1 also shows how structures at succeeding levels of the heat exchanger are staggered, the strips 19 at one level being between different concentric rows of tubes 14 at the adjacent levels. The fact that the axes of the tubes M 'at the two levels illustrated in FIG. 1 do not exactly register is due to the fact that the way in which the tubes are restrained against vibration is to exert opposed constraint against them (by the support members 22, 23) at succeeding levels; exaggerated, each tube would have a wave like bend along its length.

The

support members

22, 23 are conveniently fabricated by a method illustrated in FIG. 3-7. FIG. 3 shows plain strip 27 being fed stepwise to a press 28 having engaging

dies

29, 30 to impart ordinary angle bends of approximately 45 to the plane of the strip. FIG. 4 shows the angled strip being fed stepwise to a press 31 which has two identical lower dies 32, each with a recess 33 at its bottom, a first upper die 34 which has a ridge 35 on an angled body 36, and a second, spring-loaded upper die 37 having an angled body 38 projecting from a flat portion 39. The first upper and

lower dies

34, 32 respectively, cooperate to provide the looped portion 25 on succeeding bottom apexes of the angled strip, whilst the second upper and lower dies 37, 32 respectively, cooperate to produce the truncated apexes 24 and to alter the angle of the angled portions of the strips from 45 to the plane of the unbent strip to approximately 37% thereto. FIG. shows how the strip produced by the press shown in FIG. 4 is adapted for length and also given its approximate curvature. A press 40 has a tool 41 which distorts the looped portion 25, either as shown in FIG. 6 where the tool 41 opens the looper portion 25 and not only lengthens the strip but also imparts curvature suitable to fit the concave side of the strip 19, or as shown in figure 7 where a tool 41' cooperating with a groove 42 in the base plate 43 of the press 40 serves to squeeze the looped portions 25 and not only shortens the strip but also imparts curvature suitable to fit the convex side of a strip 19.

After forming the two varieties of

support member

22, 23, the complete structure is made up employing jigs to obtain the correct spacing for the tubes 14, the truncated apexes 24 being finally welded to the strips 19 when the correct positions for contacting the tubes 14 are accomplished. The looped portions 25 allow any necessary last-minute adjustments, as determined by the jigs, to be made.

In the heat exchanger shown in FIG. 1 of the drawings there are an odd number of concentric annular rows of the tubes 14. In one of the structures the inner annular structural member 16 carries a support member 23 supporting the inner row of tubes 14 whereas in the adjacent structure 15 the outer annular structural member 17 carries a support member 22 supporting the outer row of tubes 14. The arrangement may be applied to a heat exchanger having an even number of concentric rows of heat exchange tubes 14 in which case the one structure 15 would have support

members

22 and 23 respectively on the outer and inner annular

structural members

17 and 16 supporting the outer and inner rows of tubes M whereas in the adjacent support structure 15 the inner and outer rows of tubes 14 would be supported by support members carried by the part annular strips 19 occupying the spacers between the inner and next row of heat exchange tubes 14 and the outer and inner adjacent rows of tubes 14.

1. A heat exchanger in which a parallel array of heat exchange tubes is arranged in a container, including a support structure for maintaining correct lateral spacing of the tubes, said support structure comprising a structural framework having components extending laterally through the spaces between the tubes and support members for the tubes mounted on the components of the structural framework, said support members being adapted to provide lateral support for rows of the heat exchange tubes, the support members comprising strip material bent in the form of a zigzag so that adjacent flanks of the zigzag strip material are adapted to contact and provide lateral location for the heat exchange tubes, the apexes of the zigzag strip material, at least on one side, comprising a length of strip material greater than the length required for the flanks to meet at a point, said length forming looped portions capable of being opened or closed so as to allow variation in the angle between the flanks of the zigzag strip material on either side of the looped portions to provide for adaption of the zigzag strip material to conform with variations ofpitch in the rows of heat exchanger tubes.

2. A heat exchanger as claimed in claim 1, the heat exchange tubes of the heat exchanger being longitudinally arranged parallel to one another in the container and being concentrically pitched, said support structure for maintaining correct lateral spacing of the heat exchange tubes comprising main radially extending components and radially spaced part annular strips connected at their ends to the radially extending components, the part annular strips being disposed so as to extend circumferentially through alternate spaces between the concentric rows of heat exchange tubes, a support member of zigzag strip material having truncated apexes along one side being secured at the truncated apexes to each side of each part annular strip, the non secured apexes of the support members of zigzag strip material comprising looped portions, as defined in claim l, the part annular strips of the structural framework and the support members of zigzag strip material being edgeon to axial flow of heat exchange fluid over the heat exchange tubes, adjacent flanks of the support members of zigzag strip material contacting and providing lateral location for the corresponding heat exchange tubes, the angle between the tube supporting adjacent flanks of the support member on the convex outer side of each part annular strip of the support structure being greater than the angle between the tube supporting adjacent flanks of the corresponding support member on the convex inner side of said part annular strip to allow for the pitch of the concentric row of heat exchange tubes on the outside of the part annular strip being greater than the pitch of the concentric row of heat exchange tubes on the inside of the part annular strip.

3. A heat exchanger as claimed in claim 2, having a plurality of support structures disposed at spaced positions along the length of the heat exchange tubes, the part annular strips of the structural framework in each support structure being disposed so as to extend through the spaces between concentric rows of the heat exchange tubes which are unoccupied by the part annular strips of the structural frameworks of adjacent support structures, the arrangement being such that with respect to each heat exchange tube the support members of adjacent support structures act on the heat exchange tube in opposite directions.

4. A heat exchanger as claimed in claim 3 wherein the support members of the support structure are arranged to hold each heat exchange tube in a waved configuration.

5. A heat exchanger as claimed in claim 3 having an odd number of concentric rows of heat exchange tubes, each of the support structures having an inner peripheral component extending circumferentially inside the inner row of heat exchange tubes and an outer peripheral component extending circumferentially around the outer row of heat exchange tubes, the inner row of heat exchange tubes being supported from each of the inner peripheral components in alternate support structures by a support member of zigzag strip material similar to the support members of zigzag strip material which support the heat exchange tubes in the body of the support structures, the part annular strips carrying the support members in the body of said alternate support structures occupying alternate spaces between the concentric rows of heat exchange tubes starting with the space between the second and third concentric rows of heat exchange tubes from the inside and ending with the space between the outer and inner adjacent row of heat exchange tubes, the outer row of heat exchange tubes being supported from each of the outer peripheral components of the other alternate support structures by a support member of zigzag strip material also similar to the support members of zigzag strip materiai which support the heat exchange tubes in the body of the support structures, the part annular strips carrying the support members in the body of said other alternate support structures occupying alternate spaces between the concentric rows of heat exchange tubes starting with the space between the inner and second row of heat exchange -tubes from the-inside and ending with the space between the second and third row of heat exchange tubes from the outside.

6. A heat exchanger as claimed in claim 3 having an even number of concentric rows of heat exchange tubes, alternate support structures along the length of the heat exchange tubes having an inner peripheral component extending circumferentially inside the inner row of heat exchange tubes and an outer peripheral component extending circumferentially around the outer row of heat exchange tubes,'the inner and outer peripheral components in said alternate support structures carrying support members of zigzag strip material which support the inner and outer rows of heat exchange tubes, said support members of zigzag strip material being similar to the support members of zigzag strip material which support the heat exchange tubes in the body of the support structures, the part annular strips carrying the support members in the body of the said alternate support structures occupying alternate spaces between the concentric rows of heat exchange tubes starting with the space between the second and third rows of heat exchange tubes from the inside and ending with the space between the second and third rows of heat exchange tubes from the outside, the part annular strips carrying the support members in the body of the other alternate support structures occupying alternate spaces between the concentric rows of heat exchange tubes starting with the space between the inner and second row of heat exchange tubes from the inside and ending with the space between the outer and inner adjacent row of heat exchange tubes.

7. A heat exchanger in which a parallel array of heat exchange tubes is arranged in a container, including a support structure for maintaining correct lateral spacing of the tubes, said support structure comprising a structural framework having components extending laterally through the spaces between alternate rows of tubes, the tubes and support members for the tubes mounted on either side of the components of the structural framework, said support members being adapted to provide lateral support for the two rows of heat exchange tubes on the two sides of each component carrying the support members, the support members comprising strip material bent in the form of a zigzag so that adjacent flanks of the zigzag strip material are adapted to contact and provide lateral location for the heat exchange tubes, the apexes of the zigzag strip material, at least on one side, comprising a length of strip material greater than the length required for the flanks to meet at a point, said length forming looped portions capable of being opened or closed so as to allow variation in the angle between the flanks of the zigzag strip material on either side of the looped portions to provide for adaption of the zigzag strip material to conform with variations of pitch in the rows of heat exchanger tubes.

Claims

1. A heat exchanger in which a parallel array of heat exchange tubes is arranged in a container, including a support structure for maintaining correct lateral spacing of the tubes, said support structure comprising a structural framework having components extending laterally through the spaces between the tubes and support members for the tubes mounted on the components of the structural framework, said support members being adapted to provide lateral support for rows of the heat exchange tubes, the support members comprising strip material bent in the form of a zigzag so that adjacent flanks of the zigzag strip material are adapted to contact and provide lateral location for the heat exchange tubes, the apexes of the zigzag strip material, at least on one side, comprising a length of strip material greater than the length required for the flanks to meet at a point, said length forming looped portions capable of being opened or closed so as to allow variation in the angle between the flanks of the zigzag strip material on either side of the looped portions to provide for adaption of the zigzag strip material to conform with variations of pitch in the rows of heat exchanger tubes.

2. A heat exchanger as claimed in claim 1, the heat exchange tubes of the heat exchanger being longitudinally arranged parallel to one another in the container and being concentrically pitched, said support structure for maintaining correct lateral spacing of the heat exchange tubes comprising main radially extending components and radially spaced part annular strips connected at their ends to the radially extending components, the part annular strips being disposed so as to extend circumferentially through alternate spaces between the concentric rows of heat exchange tubes, a support member of zigzag strip material having truncated apexes along one side being secured at the truncated apexes to each side of each part annular strip, the non secured apexes of the support members of zigzag strip material comprising looped portions, as defined in claim 1, the part annular strips of the structural framework and the support members of zigzag strip material being edge-on to axial flow of heat exchange fluid over the heat exchange tubes, adjacent flanks of the support members of zigzag strip material contacting and providing lateral location for the corresponding heat exchange tubes, the angle between the tube supporting adjacent flanks of the support member on the convex outer side of each part annular strip of the support structure being greater than the angle between the tube supporting adjacent flanks of the corresponding support member on the convex inner side of said part annular strip to allow for the pitch of the concentric row of heat exchange tubes on the outside of the part annular strip being greater than the pitch of the concentric row of heat exchange tubes on the inside of the part annular strip.

5. A heat exchanger as claimed in claim 3 having an odd number of concentric rows of heat exchange tubes, each of the support structures having an inner peripheral component extending circumferentially inside the inner row of heat exchange tubes and an outer peripheral component extending circumferentially around the outer row of heat exchange tubes, the inner row of heat exchange tubes being supported from each of the inner peripheral components in alternate support structures by a support member of zigzag strip material similar to the support members of zigzag strip material which support the heat exchange tubes in the body of the support structures, the part annular strips carrying the support members in the body of said alternate support structures occupying alternate spaces between the concentric rows of heat exchange tubes starting with the space between the second and third concentric rows of heat exchange tubes from the inside and ending with the space between the outer and inner adjacent row of heat exchange tubes, the outer row of heat exchange tubes being supported from each of the outer peripheral components of the other alternate support structures by a support member of zigzag strip material also similar to the support members of zigzag strip material which support the heat exchange tubes in the body of the support structures, the part annular strips carrying the support members in the body of said other alternate support structures occupying alternate spaces between the concentric rows of heat exchange tubes starting with the space between the inner and second row of heat exchange tubes from the inside and ending with the space between the second and third row of heat exchange tubes from the outside.

6. A heat exchanger as claimed in claim 3 having an even number of concentric rows of heat exchange tubes, alternate support structures along the length of the heat exchange tubes having an inner peripheral component extending circumferentially inside the inner row of heat exchange tubes and an outer peripheral component extending circumferentially around the outer row of heat exchange tubes, the inner and outer peripheral components in said alternate support structures carrying support members of zigzag strip material which support the inner and outer rows of heat exchange tubes, said support members of zigzag strip material being similar to the support members of zigzag strip material which support the heat exchange tubes in the body of the support structures, the part annular strips carrying the support members in the body of the said alternate support structures occupying alternate spaces between the concentric rows of heat exchange tubes starting with the space between the second and third rows of heat exchange tubes from the inside and ending with the space between the second and third rows of heat exchange tubes from the outside, the part annular strips carrying the support members in the body of the other alternate support structures occupying alternate spaces between the concentric rows of heat exchange tubes starting with the space between the inner and second row of heat exchange tubes from the inside and ending with the space between the outer and inner adjacent row of heat exchange tubes.