FIELD
Embodiments of the present invention relate generally to a heat exchanging apparatus, heat exchanger, method of use and method of manufacturing, and more particularly to embodiments providing a plurality of bundled round heat exchange tubes comprising individually segmented sections generally having a twisted configuration capable of operably self-supporting the respective tubes within the heat exchanger.
CROSS-REFERENCE TO RELATED APPLICATIONS
The present application claims priority to and incorporates by reference in its entirety U.S. Provisional Patent Application No. 62/660,089 titled “Tube Bundle for Heat Exchanger and Method of Supporting Same within Heat Exchanger Shell” filed on Apr. 19, 2018.
BACKGROUND
Tubular heat exchangers, including shell-and-tube and hairpin (multitube) type heat exchangers, are used in a wide variety of applications to create heat exchange between streams of various fluids. Such heat exchangers generally include a combination, or bundle, of tubes housed within a cylindrically shaped shell. In operation, a first fluid, commonly referred to as the “tube-side fluid,” is directed through at least some of the tubes of the tube bundle. Concurrently, a second fluid, commonly referred to as the “shell-side fluid,” is directed within the shell and into any void around the tubes comprising the tube bundle, wherein the tube wall of each tube can permit heat exchange between the tube-side fluid stream flowing within the tubes and the shell-side fluid stream flowing around the tubes.
Generally, the tube bundle of a tubular heat exchanger includes a plurality of separate, self-contained individual tubes that extend in parallel to each other, wherein one or both of the ends of each respective tube is fixed to a header plate or a plurality of header plates, which are known as tube sheets. In applications that demand generally elongated heat exchangers of various lengths, known tubes and tube bundles, and the various designs thereof, of tubular heat exchangers, including shell-and-tube or hairpin (multitube) type heat exchangers, are subject to sagging and vibrations, both of which can negatively affect the heat exchanger and its components. To mitigate the negative effects of tube sagging and vibration, known tubes and tube bundles of tubular heat exchangers require intermediate support structures or members at various points over the length of the tubes or tube bundle. Such intermediate support structures or members can include spaced-apart baffles (e.g., segmented baffles), which generally consist of plates having holes or openings to receive and support the tubes and may further include spaces or voids for permitting the flow of shell-side fluid. In addition to supporting the tubes and maintaining the desired position of the same within the shell, such baffles may generally redirect the flow of the shell-side fluid, such that it flows across, rather than along, the tubes. In this way, such baffles generally inhibit the flow of the shell-side fluid along the length of the tubes. Other types of supports can consist of grids or rods.
Although baffles designs can vary and have any number of configurations and features to suit a particular application, baffle positioning and spacing can pose a difficult design challenge and create an impediment to efficient and optimal heat exchanger operation. In particular, when the spacing between a series of baffles is reduced to address the sagging and vibration of a specific tube or tube bundle, the limited space between the baffles can adversely affect the heat exchanger by reducing the flow area for the shell-side fluid, which results in excessive shell-side pressure drop.
Thus, there is a need in the art for an improved design for a tube, a tube bundle, and a heat exchanger that can effectively support the tube or the tube bundle within the shell for use in connection with low shell-side pressure drop designs or applications, while also avoiding sagging and vibration of the tubes.
FIGURES
FIG. 1 is a perspective view of an exemplary heat exchanger in accordance with embodiments presented herein;
FIG. 2 is a partial side elevation schematic representation of an exemplary heat exchanger in accordance with embodiments presented herein;
FIG. 3 is a partial detail side representation of tube sections of a heat exchanger in accordance with embodiments presented herein;
FIG. 4 is a cross-sectional representation taken generally along line 4-4 of FIG. 3 in the direction of the arrows and showing a tube bundle in accordance with the embodiment shown in FIG. 3;
FIG. 5 is a cross-sectional representation taken generally along line 5-5 of FIG. 3 in the direction of the arrows and showing a tube bundle in accordance with the embodiment shown in FIG. 3;
FIG. 6 is a cross-sectional representation taken generally along line 6-6 of FIG. 3 in the direction of the arrows and showing a tube bundle in accordance with the embodiment shown in FIG. 3;
FIG. 7 is a cross-sectional representation taken generally along line 7-7 of FIG. 3 in the direction of the arrows and showing a tube bundle in accordance with the embodiment shown in FIG. 3;
FIG. 8 is a cross-sectional representation taken generally along line 8-8 of FIG. 3 in the direction of the arrows and showing a tube bundle in accordance with the embodiment shown in FIG. 3;
FIG. 9 is a cross-sectional representation taken generally along line 9-9 of FIG. 3 in the direction of the arrows and showing a tube bundle in accordance with the embodiment shown in FIG. 3; and
FIG. 10 is a cross-sectional representation taken generally along line 10-10 of FIG. 3 in the direction of the arrows and showing a tube bundle in accordance with the embodiment shown in FIG. 3.
DETAILED DESCRIPTION
Embodiments presented herein are generally directed to a heat-exchanging apparatus, a heat exchanger, a method of manufacture and method of carrying out heat exchange providing segmented twisted sections of bundled heat exchange tubes. Embodiments disclosed herein can be provided or practiced with any number of exemplary heat exchanger designs, including for example a shell-and-tube or hairpin (multitube) type heat exchanger or multi-pass arrangements, and/or designs implementing parallel (co-current) or counter-flow arrangements.
With reference to the drawings, FIG. 1 schematically depicts a perspective illustration of a heat exchanger 100 according to an exemplary embodiment of the present invention. As best illustrated in FIG. 1, a tubular heat exchanger 100 can be generally elongated and comprise an inlet 102, an outlet 104, and tubes 120 or a tube bundle 140. The tubular heat exchanger 100 of FIG. 1 is depicted without a shell or other common heat exchanger components (e.g., a shroud, and so on). However, it will be understood that heat exchanger 100 may comprise such components without limitation.
FIG. 2 representatively illustrates a partial side schematic representation view of a heat exchanger 100 according to an exemplary embodiment provided herein, and more particularly to an exemplary bundle 140 of individual tubes 120 having a generally U-shaped arrangement. As shown in FIG. 2, the U-shaped bundle 140 of tubes 120 can comprise a plurality of generally elongated tubes 120 having at least a first leg portion 142 and a second leg portion 144 extending substantially parallel to each other along their lengths. According to the embodiment illustrated in FIG. 2, it will be recognized that portions 142, 144 of tubes 120 within the tube bundle 140 are in fluid communication with each other so that tube-side fluid within an interior passageway of the tubes can be permitted to flow in a first direction along the first leg portion 142 of a U-shaped tube 120 from an inlet 102 and into the U-shaped portion 146, where the tube-side fluid can reverse direction and flow back in a second direction, opposite to the first direction, along the second leg portion 144 of a U-shaped tube 120 to an outlet 104.
Although FIG. 2 depicts the tube bundle 140 generally comprising a linear first leg portion 142 and a linear second leg portion 144 that are joined by a generally U-shaped portion 146, it will be understood that the tube bundle 140 can comprise any of a number of shapes, whether presently known or later developed, including, without limitation, generally triangular shapes, generally rectangular shapes, and any similar symmetrical and non-symmetrical shapes or series of shapes that are joined by any number of rounded portions that have varying arc lengths and radius sizes. Further, a preferred embodiment of the present invention can be used with alternate tube bundle arrangements including, for example, straight tube or shell arrangements, single or multi-pass arrangements, and/or designs implementing parallel (co-current) or counter-flow arrangements.
As shown schematically in FIG. 2, according to exemplary embodiments the fluid tubes 120 of the tube bundle 140 can generally comprise an alternating series of individually segmented sections 150, in fluid communication with each other, comprising generally tubular straight sections 152 and sections further generally comprising a twisted configuration 154, which are twisted or rotated along their lengths about the respective central longitudinal axes 160 defined thereby. For example, FIG. 2 illustrates the first leg portion 142 and the second leg portion 144 of each tube 120 as having four straight sections 152 and three twisted sections 154 along their lengths, including (in sequence, from left to right): a first straight section 152, a first twisted section 154, a second straight section 152, a second twisted section 154, a third straight section 152, a third twisted section 154, and a fourth straight section 152 leading into the U-shaped portion 146. Thus, each tube 120 of the tube bundle 140 is shown as providing a series 150 of intermittent twisted sections 154 spaced apart by straight or untwisted tube sections 152. However, it will be understood that a preferred embodiment of the present invention can comprise a first straight section 152, generally corresponding with the entire length of the first leg portion 142, and a first twisted section 154, generally corresponding with the entire length of the second leg portion 144, or any variation thereof. Further, although FIG. 2 depicts the alternating series of individually segmented sections 150 as being generally equal or consistent in length, it will be understood that the length of any straight section 152 or any twisted section 154 can vary relative to any other straight section 152 or twisted section 154. According to exemplary embodiments as shown schematically in FIG. 2, the twisted tube sections 154 of the plurality of tubes can be generally positioned in alignment with one another and the straight tube sections 152 can be generally positioned in alignment with one another.
As shown schematically in FIG. 2, in a preferred embodiment, the intermittent twisted sections 154 of the first leg portion 142 and the intermittent twisted sections 154 of the second leg portion 144 of each tube 120 within the tube bundle 140 can be aligned so that the twisted sections 154 of each leg portion are generally laterally adjacent to the twisted sections 154 of the other leg portion. Although FIG. 2 illustrates a specific number and location of alternating twisted sections 154 and straight sections 152, it will be understood that embodiments are not limited to such and that such alternating sections 150 can be provided in alternative numbers or locations, without limitation.
The twisted sections 154, interspersed between straight sections 152, are advantageous because they can generally result in a more efficient conversion of pressure drop across the shell-side of the tubes 120 and the tube bundle 140. Specifically, the twisted sections 154, and the arrangement thereof, can mitigate the negative effects of tube sagging and vibration of the tubes 120, because the twisted sections 154, and the arrangement thereof, increases the mechanical resonant frequency of the tube 120, which can make the tubes 120 and any bundle 140 of such tubes 120 more resistant to lateral deflection from forces generated by shell-side fluid flow through the heat exchanger 100. In this way, the twisted sections 154, and the arrangement thereof with straight sections 152, eliminate the need for closely-spaced intermediate support structures or members at various points along the length thereof and, in some instances, the need for intermediate support structures or members at all. The improvement being advantageous over tubes, arrangements of tubes, and tube bundles that comprise either entirely straight tubes or tubes that are twisted over their entire lengths, without the alternating series of individually segmented straight sections and twisted sections 150. Further, the twisted sections 154 can promote the efficiency of heat transfer between tube-side fluid and shell-side fluid when compared to known tube arrangements. First, by eliminating the need for closely-spaced intermediate support structures or members at various points on the length of the tube 120 or tube bundle 140, such configuration requires less baffles, or even no baffles, to support and maintain the tubes 120 or the tube bundle 140, which reduces the inhibiting effect of such baffles on the flow of the shell-side fluid along the length of the tubes. Second, by eliminating the need for closely-spaced intermediate support structures or members at various points on the length of the tube 120 or tube bundle 140, such configuration does not create the excessive shell-side pressure drop common to known configurations and spacings of baffles used in heat exchangers.
FIG. 3 representatively illustrates a partial detail representation of the side of a twisted section 154 of three (3) tubes 120 of a tube bundle 140 according to exemplary embodiment. FIGS. 4-10 further depict representations of the various cross-sections at specific rotational intervals along the length of a segment S of the respective tubes 120 in FIG. 3. As best shown in FIGS. 3-10, between segment S, each tube 120 is twisted or rotated about a central longitudinal axis 160 at least 360°, or one complete revolution, with each cross-section view along segment S showing rotation on the order of approximately 60° from any immediately adjacent cross-section. In a preferred embodiment, the segment S can be approximately between three (3) inches and sixteen (16) inches, or approximately between five (5) inches and ten (10) inches, depending on the diameter of the respective tube 120, which can vary between approximately 0.625 inches in diameter and one (1) inch in diameter. In a preferred embodiment, each tube 120 can complete two 360° turns between any two consecutive straight sections 152. As shown schematically in FIG. 3, the exterior surfaces of tubes 120 avoid contact along the straight sections 152.
FIGS. 4-10 schematically illustrate rotation of tubes 120 within a tube bundle 140 through a 360° portion of rotation along the twisted section 154. Although the tubes 120 according to exemplary embodiments presented herein are generally provided as having a round cross-section profile when oriented along the straight sections, FIGS. 4-10 show that such round cross-sectional profile is compressed through the twisting of the tube bodies. According to exemplary embodiments, such compression can flatten the round-cross sectional profile such that the tubes take on a generally elliptical shape as shown in FIGS. 4-10. Such compression can reduce the cross-sectional area of the tubes and causes opposing points on the sides of the tubes to protrude outward. As shown schematically in FIGS. 4-10, such protrusion can bring about contact 170 between exterior surfaces of tube bodies of adjacent tubes.
As shown schematically in FIGS. 4-10, exterior surfaces of adjacent tubes 120 of the tube bundle 140 can have a plurality of points of contact 170 along the twisted section at certain rotation intervals. According to exemplary embodiments shown in FIGS. 4-10, rotation of the tube body of each of the plurality of tubes 120 in the twisted section can be synchronized such that the tubes 120 rotate together. For example, at commencement of a twisted section as shown representatively in FIG. 4, the plurality of tubes 12 can be in an initial rotation orientation. From this orientation, as the tubes twist along the twisted segment, the tube body of each tube rotate together (tubes shown as being horizontally adjacent to one another in FIG. 4 with their end points in contact are shown as rotating counterclockwise towards the rotation interval shown in FIG. 5). In undergoing such rotation, the tubes shown as being in contact with one another in FIG. 4 taper away from one another and form new contacts (with another tube) at the rotation interval of FIG. 5. Such contact and separation continues as the tubes rotate through the twisted section. It will be recognized that FIG. 7 represents a rotation interval taken on the order of 180° from the initial rotation orientation of FIG. 4. Accordingly, the right side of a tube in FIG. 4 would be shown as being the left side in FIG. 7.
Each of FIGS. 4-10 show tubes 120 of an exemplary tube bundle 140 at a particular rotation interval taken on the order of 60° through a full 360° of rotation of a twisted segment. For example, with respect to an interior tube of the tube bundle 140 in FIG. 4 which is surrounded by adjacent perimeter tubes, such interior tube 120 can have a first point of contact 170 with an adjacent tube 120 directly to its right and a second point of contact 170 with the adjacent tube 120 directly to its left. In FIG. 5, the centermost tube has the first point of contact 170 with the adjacent tube 120 to its upper-right and the second point of contact 170 with the adjacent tube 120 to its lower-left. In FIG. 6, the centermost tube 120 has the first point of contact 170 with the adjacent tube 120 to its upper-left and the second point of contact 170 with the adjacent tube 120 to its lower-right. Then, in FIG. 7, the centermost tube 120 has the first point of contact 170 with the adjacent tube 120 directly to its left and the second point of contact 170 with the adjacent tube 120 directly to its right. In this way, the centermost tube 120 can encounter eight (8) different points of contact 170 through 180° of revolution along a portion of segment S, as represented by FIGS. 4-7. In contrast, as shown in FIGS. 4-7, with respect to any tube 120 other than the centermost tube 120 in tube bundle 140, such tube can encounter four (4) different points of contact 170 through 180° of revolution along a portion of segment S. Although FIGS. 4-10 depict twisted section 154 of a tube bundle 140 comprising seven individual tubes 120, with various points of contact 170, it will be understood that the tube bundle 140 can comprise any number of tubes 120 with any number of points of contacts 170 without limitation.
According to embodiments presented herein, and shown representatively in FIGS. 2-10, the intermittent twisted sections 154 of the tubes 120 can act as a support mechanism within the heat exchanger shell and further eliminate the need for baffles altogether. Further, the twisted nature of the twisted sections 154 permits for larger voids 180 between each tube 120 in a tube bundle 140, as best illustrated in the cross-sections in FIGS. 4-10. The efficiency of heat exchange between the tube-side fluid and the shell-side fluid, via the tube wall, can be further improved over known heat exchangers by a swirl flow created by the twisted segments of tubes 120 and the voids 180. Specifically, the swirl flow can be created by a swirling region defined by the individual tubes 120 of the tube bundle 140, and generally comprising the voids 180 along the twisted sections. The shell-side fluid can travel between the voids 180, and the varying space defined thereby, and generally along the length of the tubes 120 and tube bundle 140. In this way, the shell-side fluid can be acted upon by the tubes 120 depending on the orientations thereof relative to segment S, as best depicted in FIGS. 4-10, to create a swirl effect in the shell-side fluid, which can produce a swirl flow.
Further, because a twisted section 154 is generally adjacent to an at least one straight section 152, wherein the tubes 120 of the tube bundle 140 are generally arranged in a tighter arrangement with fewer and smaller voids between the tubes, the overall mechanical resonance of the tube 120 is not adversely affected by the spacing and voids 180 of the twisted section 154. The intermittent twisted segments 154 can support the tubes 120 and tube bundles 140 within the shell in a manner that provides a highly flexible support system with enhanced heat transfer on the tube- and shell-side flows, such that each tube 120 or tube bundle 140 is generally self-supporting, even without the use of baffles. Such support can be achieved, at least in part, by the twisted segments 154 which can produce tube-to-tube spaced-apart contact points 170 between adjacent tubes 120, while also defining the voids 180 discussed herein, with each individual tube 120 being secured in place by adjacent tubes 120, and facilitating securement of adjacent tubes 120. Such arrangement can reduce vibration and promote easier cleaning on the shell-side through the heat exchanger 100.
It is important to note that the present inventions (e.g., inventive concepts, and so on) have been described in the specification and/or illustrated in the FIGURES of the present patent document according to exemplary embodiments; the embodiments of the present inventions are presented by way of example only and are not intended as a limitation on the scope of the present inventions. The construction and/or arrangement of the elements of the inventive concepts embodied in the present inventions as described in the specification and/or illustrated in the FIGURES is illustrative only. Although exemplary embodiments of the present inventions have been described in detail in the present patent document, a person of ordinary skill in the art will readily appreciate that equivalents, modifications, variations, and so on of the subject matter of the exemplary embodiments and alternative embodiments are possible and contemplated as being within the scope of the present inventions; all such subject matter (e.g., modifications, variations, embodiments, combinations, equivalents, and so on) is intended to be included within the scope of the present inventions. It should also be noted that various/other modifications, variations, substitutions, equivalents, changes, omissions, and so on may be made in the configuration and/or arrangement of the exemplary embodiments (e.g., in concept, design, structure, apparatus, form, assembly, construction, means, function, system, process/method, steps, sequence of process/method steps, operation, operating conditions, performance, materials, composition, combination, and so on) without departing from the scope of the present inventions; all such subject matter (e.g., modifications, variations, embodiments, combinations, equivalents, and so on) is intended to be included within the scope of the present inventions. The scope of the present inventions is not intended to be limited to the subject matter (e.g., details, structure, functions, materials, acts, steps, sequence, system, result, and so on) described in the specification and/or illustrated in the FIGURES of the present patent document. It is contemplated that the claims of the present patent document will be construed properly to cover the complete scope of the subject matter of the present inventions (e.g., including any and all such modifications, variations, embodiments, combinations, equivalents, and so on); it is to be understood that the terminology used in the present patent document is for the purpose of providing a description of the subject matter of the exemplary embodiments rather than as a limitation on the scope of the present inventions.
It is also important to note that according to exemplary embodiments the present inventions may comprise conventional technology (e.g., as implemented and/or integrated in exemplary embodiments, modifications, variations, combinations, equivalents, and so on) or may comprise any other applicable technology (present and/or future) with suitability and/or capability to perform the functions and processes/operations described in the specification and/or illustrated in the FIGURES. All such technology (e.g., as implemented in embodiments, modifications, variations, combinations, equivalents, and so on) is considered to be within the scope of the present inventions of the present patent document.
Patent Application
20210140715
