BACKGROUND
This application relates to coil-wound heat exchangers (CWHEs) and, more particularly, to methods and systems for supporting individual tube layers of a CWHE tube bundle.
CWHEs are frequently used in the process industries for heating or cooling fluid streams at high heat transfer rates that require large heat transfer areas. CWHEs utilize tube bundles constructed of multiple long tubes that are helically wound about an axial central core called a mandrel. The tube bundle is encased within a shroud. The tube bundles and the mandrel are sealed within a shell which provides a pressure boundary. The mandrel, shell, and shroud provide structure for the CWHE and allow for the connectivity of other operational components. The multiple long tubes are wound to form one or more helical structures having different diameters. This creates a tube bundle that includes multiple tube layers which are formed in the radial direction, with each outwardly positioned tube layer increasing in diameter with respect to a preceding inner tube layer. Adjacent tube layers are often maintained at a desired separation distance from one another (also referred to as layer spacing) by axial spacers. Such spacers are often solid rods or wires. Spacers typically have a round cross-sectional shape, but may have a different cross-sectional geometry (e.g., oval, square, rectangular, etc.). Each tube may be supported by supports that may be circumferentially spaced between each tube layer and may be positioned parallel to the mandrel. In other implementations, the spacers may be positioned in a spiral arrangement and/or have non-uniform spacing. Each support may include pre-formed recesses or other structures that hold or cradle the tubes, thereby holding them in a desired position.
One drawback of preformed supports is that each preformed support can only be used with a tube bundle having a specific tube bundle geometry, including number and size (diameter) of tubes, desired tube layer spacing, and tube layer winding angle. This means that different preformed supports must be provided for each CWHE having a different tube bundle geometry, which can result in higher production time and cost.
Therefore, there is a need for an improved system and method for spacing and supporting the tube layers of the tube bundle of a CWHE, in which each support is not constrained to use with a specific tube bundle geometry.
SUMMARY
The disclosed embodiments satisfy the need in the art by providing deformable support structures that are formed into a final desired configuration during the tube winding steps of CWHE construction and assembly. The structure of the deformable supports is not limited to use in a specific CWHE configuration and can have a common starting structure despite ultimate configuration of the CWHE, since the final structure of the deformable support is formed during construction of the CWHE. A deformable support structure having a single design can be manufactured to support individual tube layers in a manner that achieves the radial and axial stiffness required and used throughout the CWHE tube bundles. This deformable support can be used to support the tube bundle system under non-operational or operational conditions. In some configurations, the deformable supports may optionally have non-deformable portions that can function as a spacer and thus replace the need for a separate spacer. The deformable supports are positioned between the individual tube layers during the tube winding operation. During initial construction of the CWHE, a first deformable support structure is positioned in contact with and affixed to the mandrel prior to winding the first tube layer. The first tube layer is then wound around the mandrel such that the first deformable support is positioned between the mandrel and the first tube layer. The first deformable support structure may include non-deformable portions that can function as a spacer, such that the winding operation of the first tube layer around the mandrel will deform a portion of the deformable support, leaving the non-deformable portion unchanged so that it may provide desired spacing between the first tube layer and the mandrel. Alternatively, in instances where the deformable support structure does not include non-deformable portions, one or more separate, non-deformable spacers can also be positioned between the mandrel and the first tube layer, in order to provide a desired spacing between the first tube layer and the mandrel. After completing winding of a first tube layer, a series of additional deformable supports are positioned over the completed first tube layer. As subsequent tube layers are wound, the winding operation will deform the deformable supports and form them to follow the winding angle defined for each tube layer. The deformable supports are configured to have desired radial crush strength characteristics and axial shear strength characteristics along a longitudinal length of the shell.
Several aspects of the systems and methods are outlined below.
Aspect 1: A method of forming a tube bundle for a coil wound heat exchanger, wherein the tube bundle comprises multiple tube layers, each layer comprises at least one tube, and the method comprises:
- (a) providing a mandrel that extends along a mandrel longitudinal axis;
- (b) forming a first tube layer by winding at least one of the at least one tubes around the mandrel, the at least one tube having a tube height H;
- (c) placing a plurality of first layer supports and a plurality of first layer spacers on an outer tube surface of the first tube layer, each of the first layer supports having a support longitudinal axis, an inner support surface that is in contact with the outer tube surface and an outer surface that is distal to the inner support surface, each of the plurality of first layer spacers having a spacer height S;
- (d) forming a second tube layer by winding at least one of the at least one tubes around the mandrel, the first tube layer, and the plurality of first layer supports; and
- (e) applying at least one deforming force to the second tube layer in a direction normal to the outer support surface of each of the plurality of first layer supports sufficient to cause the at least one tube forming the second tube layer to deform at least one of the outer support surface and the inner support surface of each of the plurality of first layer supports without deforming the at least one tube forming the second tube layer.
Aspect 2: The method of Aspect 1, wherein a radial layer spacing between the first tube layer and the second tube layer is greater than the spacer height S prior to performing step (e) and is equal to the spacer height S after performing step (e).
Aspect 3: The method of any of Aspects 1 through 2, further comprising:
- (f) placing a plurality of mandrel layer supports on the mandrel prior to performing step (b), so that the mandrel layer supports are positioned between the mandrel and the first tube layer.
Aspect 4: The method of any of Aspects 1 through 3, wherein the application of the deforming force moves at least one of the outer support surface or the inner support surface of at least one of the plurality of first layer supports from an initial contact position to a recessed position, and wherein the distance E between the initial contact position and the recessed position is at least 5% of the tube height H.
Aspect 5: The method of Aspect 4, wherein the distance E is less than 50% of the tube height H.
Aspect 6: The method of any of Aspects 1 through 5, wherein the deforming force of step (e) is a result of applying tension to the second tube layer during step (d).
Aspect 7: The method of any of Aspects 1 through 6, wherein at least a portion of the deforming force of step (e) is applied by an external device that is passed over the second tube layer during or after the performance of step (d).
Aspect 8: The method of any of Aspects 1 through 7, wherein step (b) further comprises winding the at least one first layer tube around the mandrel at a winding angle α relative to the mandrel longitudinal axis and step (d) further comprises winding the at least one second layer tube at a winding angle-a relative to the mandrel longitudinal axis.
Aspect 9: The method of any of Aspects 1 through 8, wherein each of the at least one tubes has a tube radial crush strength and each of the plurality of first layer supports has a support outer layer having a support outer layer radial crush strength that is less than the tube radial crush strength.
Aspect 10: The method of Aspect 8, wherein the outer support surface of each support of the plurality of first layer supports is adapted to deform via the deforming force to create a tube seat oriented at an angle corresponding to either of the winding angle α or the winding angle-a during the performance of step (b).
Aspect 11: The method of any of Aspects 1 through 10, wherein each of the plurality of first layer supports comprises a non-deformable spacer portion that does not substantially deform during the performance of step (e).
Aspect 12: The method of any of Aspects 1 through 11, wherein step (b) further comprises arranging the plurality of first layer supports and the plurality of first layer spacers in a circumferentially-alternating arrangement on the outer tube surface of the first tube layer.
Aspect 13: The method of any of Aspects 1 through 12, further comprising:
- (g) prior to performing step (d), applying a pre-winding force to each of the plurality of first layer supports that results in a deformation of each of the plurality of first layer supports on only the inner support surface.
Aspect 14: The method of any of Aspects 1 through 13, further comprising forming one or more additional tube layers in the tube bundle by repeating steps (c) through (e) for each additional tube layer in the tube bundle.
Aspect 15: The method of any of Aspects 1 through 14, wherein each of the plurality of first layer supports placed in step (c) is also one of the plurality of first layer spacers.
Aspect 16: The method of Aspect 15, wherein each of the plurality of first layer supports comprises an inner layer and at least one outer layer, the inner layer having a maximum inner layer radial crush strength that is greater than an outer layer maximum radial crush strength of each of the at least one outer layers.
Aspect 17: A method of forming a tube bundle for a coil-wound heat exchanger, wherein the tube bundle comprises multiple tube layers, each layer comprises at least one tube, and the method comprises:
- (a) providing a mandrel that extends along a mandrel longitudinal axis;
- (b) providing a plurality of first layer supports, each of the plurality of first layer supports comprising a hollow cell material, each of the plurality of first layer supports having a support longitudinal axis and an outer support surface;
- (c) forming a first tube layer by winding at least one of the at least one tubes around the mandrel in a first circumferential direction; and
- (d) placing the plurality of first layer supports on an outer tube surface of the first tube layer.
Aspect 18: The method of Aspect 17, further comprising placing a plurality of mandrel layer supports on the mandrel prior to performing step (c), so that the mandrel layer supports are positioned between the mandrel and the first tube layer.
Aspect 19: The method of any of Aspects 17 through 18, wherein the hollow cell material of each of the plurality of first layer supports comprises at least one open cell.
Aspect 20: The method of any of Aspects 17 through 19, wherein the hollow cell material of each of the plurality of first layer supports comprises at least one open cell and at least one closed cell.
Aspect 21: The method of any of Aspects 17 through 20, wherein each of the plurality of first layer supports comprises at least one outer layer having a first outer layer radial crush strength and at least one inner layer having an inner layer radial crush strength that is greater than the at least one outer layer radial crush strength.
Aspect 22: A coil-wound heat exchanger comprising:
- a shell defining an internal volume;
- at least one tube bundle located within the shell, the at least one tube bundle comprising a plurality of layers wound around a mandrel in, each of the plurality of layers comprising at least one tube, each of the at least one tubes having a radial crush strength, and each of the plurality of layers having a winding angle; and
- a plurality of supports located between each of the plurality of layers, each of the plurality of supports comprising a function-oriented material and extending substantially transverse to the winding angle or the mandrel.
Aspect 23: The coil-wound heat exchanger of Aspect 22, further comprising an initial support layer comprising one or more supports positioned between the mandrel and a first layer of the plurality of layers.
Aspect 24: The coil-wound heat exchanger of any of Aspects 22 through 23, wherein each of the plurality of supports comprises of a hollow cell material.
Aspect 25: The coil-wound heat exchanger of Aspect 24, wherein the hollow cell material of each of the plurality of supports comprises at least one open cell.
Aspect 26: The coil-wound heat exchanger of Aspect 24, wherein the hollow cell material of each of the plurality of supports comprises at least one open cell and at least one closed cell.
Aspect 27: The coil-wound heat exchanger of any of Aspects 22 through 26, wherein each of the plurality of supports further comprises a maximum radial crush strength that is less than the radial crush strength of the at least one tube.
Aspect 28: The coil-wound heat exchanger of Aspect 27, wherein each of the plurality of supports further comprises a pair of outer layers each having a maximum outer layer radial crush strength that is less than a maximum inner layer radial crush strength of the inner layer, wherein the inner layer is located between the pair of outer layers.
Aspect 29: The coil-wound heat exchanger of any of Aspects 22 through 28, wherein each of the plurality of supports comprises a first side outer surface and a second side outer surface, wherein the first side outer surface comprises a partially defined recess that extends inwardly toward the second side outer surface, whereby the partially defined recess is configured to receive at least a portion of the at least one tube.
Aspect 30: The coil-wound heat exchanger of any of Aspects 22 through 29, wherein the plurality of layers includes at least a first layer and a second layer, wherein a distance between the first layer and the second layer is between 0.5 mm to 100 mm.
Aspect 31: A method of forming a tube bundle for a coil wound heat exchanger, wherein the tube bundle comprises multiple tube layers, each layer comprises at least one tube, and the method comprises:
- (a) providing a mandrel that extends along a mandrel longitudinal axis;
- (b) forming a first tube layer by winding at least one of the at least one tubes around the mandrel, the at least one tube having a tube height H;
- (c) placing a plurality of first layer supports on an outer tube surface of the first tube layer, each of the first layer supports having a support longitudinal axis and an outer support surface;
- (d) forming a second tube layer by winding at least one of the at least one tubes around the mandrel, defining a first distance between the outer tube surface of the first tube layer and an outer tube surface of the second tube layer; and
- (e) applying a deforming force to the second tube layer in a direction normal to the outer surface of each of the plurality of first layer supports sufficient to cause the at least one tube forming the second tube layer to deform the outer support surface of each of the plurality of first layer supports, resulting in a second distance between the outer tube surface of the first tube layer and the outer tube surface of the second tube layer, wherein the second distance is less than the first distance.
Aspect 32: The method of Aspect 29, further comprising placing a plurality of mandrel layer supports on the mandrel prior to performing step (b), so that the mandrel layer supports are positioned between the mandrel and the first tube layer.
Aspect 33: The method of Aspect 29, wherein the second distance is between 0.5 mm and 100 mm.
Aspect 34: A method of forming a tube bundle for a coil wound heat exchanger, wherein the tube bundle comprises multiple tube layers, each layer comprising at least one tube, and the method comprises:
- (a) providing a mandrel that extends along a mandrel longitudinal axis;
- (b) forming a first tube layer by winding at least one of the at least one tubes around the mandrel, the at least one tube having a tube height H;
- (c) placing a plurality of first layer supports and a plurality of first layer spacers on an outer tube surface of the first tube layer in a circumferentially-alternating arrangement, each of the plurality of first layer supports having an undeformed support height H2 and each of the plurality of first layer spacers having a spacer height H1;
- (d) forming a second tube layer by winding at least one of the at least one tubes around the mandrel, the first tube layer, and the plurality of first layer supports; and
- (e) applying at least one deforming force to the second tube layer sufficient to deform each of the plurality of first layer supports without deforming the at least one tube forming the second tube layer;
- wherein the first and second tube layers have an initial layer spacing at each of the plurality of first layer supports prior to performing step 17(e) and a final layer spacing at each of the plurality of first layer supports after performing step 17(e), the final layer spacing being less than the initial layer spacing.
Aspect 35: The method of any of Aspects 1 through 34, wherein each support of the plurality of first layer supports comprises a plurality of separate support structures, such that each support of the plurality of first layer supports is discontinuous along the axial direction of the tube bundle.
Aspect 36: The method of any of Aspects 34 through 35 wherein the final layer spacing is substantially equal to the spacer height H1.
Aspect 37: The method of any of Aspects 34 through 36 wherein the initial layer spacing is substantially equal to the undeformed support height H2.
BRIEF DESCRIPTION OF THE DRAWING(S)
The present invention will hereinafter be described in conjunction with the appended drawing figures, wherein like numerals denote like elements.
FIG. 1 is a cut-away perspective view of an exemplary prior art CWHE.
FIG. 2 is a sectional view taken along line 2-2 of FIG. 1.
FIG. 3 is a side elevation cut-away view of an exemplary prior art CWHE showing an illustrative example of a prior art support system.
FIG. 4 is a schematic side view of a prior art spacer located between two layers of a tube bundle.
FIG. 5 is a schematic side view of a prior art preformed support.
FIG. 6 is a schematic side view of the preformed support of FIG. 5 located between two layers of a tube bundle.
FIG. 7 is a schematic side view of an exemplary deformable support of the present invention, with two layers of a tube bundle shown prior to deforming the deformable support.
FIG. 8 is a schematic side view of the two layers of the tube bundle and the deformable support of FIG. 7, shown after deforming the support.
FIG. 9 is an enlarged partial view of area 9-9 of FIG. 7.
FIG. 10 is an enlarged partial view of area 10-10 of FIG. 8.
FIG. 11 is a schematic side view of the two layers of the tube bundle and another exemplary deformable support, showing an alternate method of providing a normal force used to deform the support.
FIG. 12 is a schematic side view of the two layers of the tube bundle and another exemplary deformable support after the deformable support has been deformed.
FIG. 13 is a schematic side view of another exemplary deformable support having partially defined recesses configured to receive the two layers of the tube bundle prior to the deformable support being deformed.
FIG. 14 is a schematic side view of the two layers of the tube bundle and another exemplary deformable support after one portion of the deformable support has been deformed.
FIG. 15 is a schematic side view of the two layers of the tube bundle and another exemplary deformable support after one portion of the deformable support has been deformed, wherein the deformable support includes a static non-deformable portion configured to receive the two layers of the tube bundle prior to the deformable support being deformed.
FIG. 16 is a flowchart showing steps from a first exemplary method for forming a tube bundle for a CWHE utilizing an exemplary support system.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The ensuing detailed description provides preferred exemplary embodiments of the present invention only, and is not intended to limit the scope, applicability, or configuration of the invention. Rather, the ensuing detailed description of the preferred exemplary embodiments will provide those skilled in the art with an enabling description for implementing the preferred exemplary embodiments of the invention, it being understood that various changes may be made in the function and arrangement of elements without departing from the spirit and scope of the invention.
In order to aid in describing the invention, directional terms may be used in the specification and claims to describe portions of the present invention (e.g., upper, lower, left, right, etc.). These directional terms are merely intended to assist in describing and claiming the invention and are not intended to limit the invention in any way. In addition, reference numerals that are introduced in the specification in association with a figure may be repeated in one or more subsequent figures without additional description in the specification in order to provide context for other features.
Unless otherwise indicated, the articles “a” and “an” as used herein mean one or more when applied to any feature in embodiments of the present invention described in the specification and claims. The use of “a” or “an” does not limit the meaning to a single feature unless such a limit is specifically stated. The article “the” preceding singular or plural nouns or noun phrases denotes a specified feature or specified features and may have a singular or plural connotation depending upon the context in which it is used.
In the claims, letters are used to identify claimed steps (e.g. (a), (b), and (c)). These letters are used to aid in referring to the method steps and are not intended to indicate the order in which claimed steps are performed, unless and only to the extent that such order is specifically recited in the claims.
As used in the specification and the claims, the term “hollow cell material” means a material that comprises at least one hollow cell, or an array of hollow cells. A “hollow cell” is defined as a volumetric void within a material. A hollow cell material may include “open cells,” with at least one volumetric void that is visible through or open to an exterior side of the hollow cell material, and/or “closed cells,” with at least one volumetric void that is entirely enclosed by the exterior sides of the hollow cell material. The volumetric void of the “closed cell” may also be filled with a material. A hollow cell material may include any combination of open cells and closed cells.
As used in the specification and in the claims, the term “crush strength” means the amount of force required to deform an outer surface of a material a distance of one millimeter.
As used in the specification and claims, the term “function-oriented material” means a deformable material that is formed to meet desired radial crush characteristics. Examples of function-oriented materials include hollow cell, open cell, closed cell, honeycomb, fin tubes, and knitted wire mesh forms. The term “functionally graded structural material” is a function-oriented material that is formed in a way that provides a radial crush characteristics that increase in a continuous or step-wise manner from one side to another.
As used in the specification and in the claims, the term “radial crush strength” means the amount of force required to deform an outer surface of a material a distance of one millimeter, whereby the force is applied in a direction that is normal to an outer surface and orthogonal to a longitudinal axis of the material being tested. It should be noted that the deforming force (force vector) may include a component that is normal to the outer surface and another component that is not normal to the outer surface.
As used in the specification and in the claims, the term “preformed,” as applied to an article such as a support, means the article is manufactured to have a particular static structure and shape prior to the article being utilized in the assembly of a larger overall system, whereby the assembly process of the larger overall system does not alter the static structure and shape of the article, and the article maintains its initial structure and shape after assembly of the larger overall system.
As used in the specification and in the claims, the term “deformable,” as applied to an article such as a support, means at least a portion of the article includes material or structural characteristics that are adapted to allow a change in shape of at least a portion of an outer surface of the article during an assembly process whereby the article is installed as part of a larger overall system.
As used in the specification and in the claims, the term “non-deformable,” as applied to an article such as a support, means at least a portion of the article includes either material or structural characteristics that are adapted to maintain an initial shape of at least a portion of an outer surface of the article during an assembly process whereby the article is installed as part of a larger overall system. An article may include any combination of both “deformable” and “non-deformable” portions.
As used in the specification and in the claims, the term “crush zone,” as applied to an article such as a support, defines at least a portion of the article that is adapted to be “deformable” as defined above.
FIGS. 1 through 6 illustrate prior art CWHEs and support systems. Referring to FIG. 1, a CWHE 100 includes a pressure boundary or shell 102. At least one tube 106 is wound in a circumferential direction C around a central mandrel 108 to form tube layers in a multi-layered tube bundle 109, which may be encased within a shroud 104. Preformed supports 118 are utilized to support each of the individual tube layers in a vertical stacked structure, and preformed spacers (not visible) are utilized to maintain a desired spacing between the individual tube layers of the multi-layered tube bundle 109, which allows for fluid within the shell 102 to flow between the individual tube layers. FIG. 2 shows how the at least one tube 106 is wound around the mandrel to form individual tube layers of the multi-layered tube bundle 109 that extend radially outwardly from the mandrel 108. Each individual tube layer comprises at least one tube 106, and each tube layer may comprise the same or different tubes 106 from an adjacent layer. As a result, a single tube may be used to form at least part of multiple tube layers or the tube layers may instead be formed from one or more tubes that are different from the one or more tubes forming adjacent tube layers.
FIG. 3 is a side elevation cut-away view of a CWHE showing an illustrative example of a prior art support system. The mandrel 108 is shown extending along a longitudinal axis Z. At least one tube 106 is wound around the mandrel 108 in a circumferential direction C and at a desired winding angle α relative to the mandrel longitudinal axis Z to form a first tube layer 112. At least one tube 106 is further wound at a winding angle-a relative to the mandrel longitudinal axis Z in the circumferential direction C in order to form a second tube layer 114. The first tube layer 112 and second tube layer 114 comprise a tube bundle 109, which may include additional tube layers beyond the first tube layer 112 and the second tube layer 114. Each of the first tube layer 112 and the second tube layer 114 is supported in a desired vertical position via supports 118, which extend parallel to the mandrel 108 and substantially transverse to the winding angle. In this context “substantially transverse” means that the supports extend along an axis that forms an angle of between 70 and 110 degrees with the winding angle α. The supports 118 are adapted to provide a load-bearing structure for the tube bundle 109 during non-operational and/or operational loads. At least one spacer 119, which also extends parallel to the mandrel 108, provides and maintains a desired separation distance between individual tube layers 112, 114. In an illustrative example, the separation distance between the first tube layer 112 and the second tube layer 114 is between 0.5 mm and 100 mm. Although not shown in FIG. 3, a support layer may also be provided between the mandrel 108 and the first tube layer 112.
FIG. 4 shows an example of a prior art spacer system. Individual tubes 206a-f of a tube bundle 209 are separated at a desired center-to-center distance Dt, wherein Dt is equal to the distance between axial midpoints of any two adjacent individual tubes, such as between tube 206a and tube 206b, for example. Each of the first tube layer 212 and the second tube layer 214 is separated at a desired distance Ds by a spacer 219, wherein Ds is equal to the distance between the axial midpoints of any two of the individual tubes 206a-f across each of the first tube layer 212 and the second tube layer 214, such as between tube 206a and 206d, for example. A support mechanism, which is not visible in this figure, provides structural support for the individual tubes 206a-f, while the spacer 219 provides for the desired spacing between the first tube layer 212 and the second tube layer 214.
FIG. 5 shows an example of a prior art support system. In the illustrated example, the support 318 includes preformed tube seats 316a-f. Each of the tube seats 316a-f is configured to receive and support at least a portion of a tube. FIG. 6 shows the support 318 from FIG. 5 in use to support tubes 306a-306f of a tube bundle 309. The preformed tube seats 316a-f are manufactured to receive and support tubes 306a-f of a particular diameter and at a particular distance between adjacent tubes 306a-f of the first tube layer 312 and the second tube layer 314, such as between tube 306a and tube 306b, for example. As noted above, preformed supports, such as support 318 are only able to be used with a particular tube bundle 309 having a tube diameter and tube spacing that matches the tube seats 316a-f. This means that different supports having differently configured tube seats need to be manufactured and stocked for each tube bundle having a different tube diameter and/or tube spacing.
FIGS. 7 through 11 show a portion of a tube bundle 409 utilizing a deformable support 418 having an outer support surface 422 that is adapted to deform during the assembly of the tube bundle 409 so that each tube 406a-f is cradled within a recess 425 formed in outer support surface 422 of the support 418, whereby the recess 425 is created as a result of the deformation of the outer support surface 422. This enables the support 418 to provide a desired spacing between the first tube layer 412 and the second tube layer 414, and to provide a load-bearing structure for the tubes 406a-f when the CWHE is fully assembled. As described herein, it is desirable for the support 418 to have physical properties, including a radial crush strength, which allow the outer support surface 422 to be deformed as the first tube layer 412 and the second tube layer 414 are installed. This enables the tubes 406a-f to become recessed into the support 418 by a controllable and predictable distance without deforming the outer tube surface 423 of any of the tubes 406a-f. At least a portion of the support 418 is configured to undergo the deformation, such portion being defined as a “crush zone”.
In an illustrative example, the deformable supports 418 and spacers (not shown) may be provided in a circumferentially-alternating arrangement, meaning that along the direction of tube winding, each support 418 is positioned between two spacers. This enables the spacers, which are not deformable, to provide a “stop” for the deformation of the deformable supports 418. This arrangement enables the supports 418 to deform and perform their support function, while precisely controlling the amount of deformation of the deformable supports 418 to provide uniform and precise layer spacing. The deformable supports 418 may be staggered in both radial and axial directions. In one illustrative example, the deformable support 418 may include a single continuous structure that extends along the axial direction Y of the tube bundle. In another illustrative example, the deformable supports 418 may comprise multiple separate structures, such that the deformable supports 418 are discontinuous along the axial direction of the tube bundle. In other implementations, supports and spacers may be provided in other arrangements/patterns as may be effective to provide the desired end result.
Prior to any deformation of a deformable support 418 (see FIG. 7), the radial spacing R between the tube layers is greater than the height of the spacers (not shown). After the support is deformed (see FIG. 8), the radial spacing R is reduced and is substantially equal to the height of the spacers. In this context, “substantially equal” may for example be within 10% of the spacer height, may be within 5% of the spacer height, or may be within 1% of the spacer height.
FIG. 7 shows the support 418 and tubes 406a-f prior to the outer support surface 422 of the support 418 being deformed. FIG. 8 shows the same support 418 after the outer support surface 418 has been deformed. The deformation of the outer support surface 422 creates recesses 425 in the outer support surface 422. The recesses 425 function as tube seats that receive and support the individual tubes 406a-f of each the first tube layer 412 and the second tube layer 414 that comprise the tube bundle 409. In the illustrative example in FIG. 7, the support 418 may be formed from a hollow cell material, which may include a plurality of open cells 420a, 420b that form at least a portion of the support 418. In the illustrative example, the open cells 420a, 420b provide a hollow cell structure that also allows fluid to cross the support 418 in a circumferential direction (see e.g., circumferential direction C of FIG. 6) with respect to the winding of the first tube layer 412 and the second tube layer 414 about the mandrel.
In the illustrative example shown in FIGS. 7-11, the support 418 may comprise a hollow cell material that includes a combination of one or more open cells 420 and one or more closed cells 421. The closed cells 421 can comprise open cells 420 that are selectively closed off after manufacture of the support 418. As one example, the closed cells 421 may be formed by filling an open cell 420 with a different material than the material that forms the rest of the support 418, whereby the material filling the closed cell 421 has a greater crush strength than the crush strength of the material which forms the rest of the support 418. The closed cells 421 may also be initially formed with the original construction of the support 418. Each closed cell 421 prevents circumferential fluid flow across its respective portion of the support 418. The support 418, when made from a hollow cell material, may include a desired number and arrangement or pattern of closed cells 421 and open cells 420, and can be filled or otherwise closed to prevent fluid flow therethrough in order to create a desired flow pattern for the circumferential fluid flow. The support 418 may consist entirely of a hollow cell material, or may include a combination of hollow cell materials and other types of materials. In other implementations, the support 418 may be deformable but not include a hollow cell material.
In order to deform the support 418 to achieve the desired configuration for the tube bundle 409, the support 418 is placed on an outer tube surface 423 of the first tube layer 412 after the first tube layer 412 has been wound around the mandrel. The second tube layer 414 is then wound around the mandrel such that it contacts the opposing side of the support 418 opposite the side of the support 418 that contacts the first tube layer 412. As shown in FIG. 7, a deforming force is applied to the outer tube surface 423 of the second tube layer 414 in a direction N which is normal to the outer support surface 422 of the support 418. In this example, the support 418 has a radial crush strength ranging from 10 N/mm to 400 N/mm.
In some examples, the support 418 may comprise a material that has a non-constant radial crush strength. For example, the radial crush strength of a material may increase as the outer surface of the material is deformed. In this example, the amount of force required to deform the outer surface of a material that has already been deformed by one millimeter an additional one millimeter is greater than the amount of force required to deform the previously undeformed outer surface of the material by one millimeter. Further, the amount of force required to deform the outer surface of a material that has already been deformed by two millimeters an additional one millimeter is greater than the amount of force required to deform the outer surface material that has already been deformed by one millimeter an additional one millimeter, and so on. This functional relationship between the radial crush strength of a material and the amount of deformation already done to the outer surface of the material may be linear, exponential, stepped, or any other type of functional relationship. In the context of such materials, when a constant-value force is applied to the material, a desired deformation of the outer surface of the material is achieved.
For purposes of the specification and claims, the term “maximum radial crush strength” means the greatest radial crush strength that occurs throughout the deformation process in the portion of the support being deformed. It is preferable that the maximum radial crush strength of the portion(s) of the support 418 being deformed by the tubes 406a-f is less than the radial crush strength of the tubes 406a-b. In this way, the normal force required to deform the support 418 can be applied to the tube 406 without causing the outer tube surface 423 of the tube 406 to deform.
In an illustrative example, the normal force may be applied via tension caused as a result of the winding operation of the second tube layer 414. In another illustrative example, as shown in FIG. 11, the normal force may be applied via a roller 428 which is rotatable about an axle 430. The normal force applied via the roller 428 is applied while the second tube layer 414 is wound around the mandrel, such that the second tube layer 414 contacts the side of the support 418 opposite the side that contacts the first tube layer 412. The pressure applied by the roller 428 as it passes over the tube 406 is configured to apply the normal force to the outer tube surface 423 of the tube 406, which causes the outer support surface 422 of the support 418 to undergo the desired deformation. The pressure applied by the roller 428 could, alternatively, be provided by another external device such as a shoe or slide which pushes the tube 406 into the support 418.
In previously discussed illustrative examples such as that shown in FIG. 8 and in other illustrative examples, the normal force applied is sufficient to cause the first tube layer 412 and the second tube layer 414 to compress and deform the inner and outer support surfaces 422, 427 of the support 418. The deformation of the support surfaces 422, 427 forms recesses 425 which act as a tube seat that receives, supports, and stabilizes the tubes 406. This results in the tubes 406a-f of the first tube layer 412 and the second tube layers 414 being in a recessed position relative to the support 418, whereby the recess 425 defines a tube seat that is oriented at an angle corresponding to either of the winding angle α or the winding angle-a, depending on which tube layer 412, 414 the recess 425 is receiving. The tubes 406a-f have a radial crush strength that is greater than the radial crush strength of the support surfaces 422, 427 of the support 418. This prevents unwanted deformation of the tubes 406a-f during deformation of the support surfaces 422, 427 of the support 418.
In another illustrative implementation, a normal force could be applied to the support 418 before the second tube layer 414 is wound (a “pre-winding force”). This would result in a deformation of only an inner support surface 427.
FIG. 9 shows a portion of a tube bundle 409 with a tube 406 in contact with the outer support surface 422 of the support 418 prior to deformation of the support 418. The broken line T illustrates an initial contact position where the tube 406 first contacts the outer support surface 422 of the support 418. FIG. 10 shows a portion of a tube bundle 409 with a tube 406 in contact with the support 418 after deformation of the support 418 has been completed, such that the newly formed recess 425 acts as a tube seat that receives, supports, and stabilizes the tube 406. The material properties of the support 418, such as the radial crush strength for example, can vary in order to achieve a desired final recessed position for the tube 406. In the illustrative example, the recessed position of the tube 406 is spaced a distance E from an initial contact position T, the distance E being at least 5% of the tube height H. In other illustrative examples, the distance E could be at least 25% of the tube height H. It should be noted that the tube 406 is shown as having a circular cross section in this exemplary implementation, and thus the tube height H is the outer diameter of the tube. In other implementations, the tube 406 could have a non-circular cross section (oval, elliptical, etc.), and the tube height H in such implementations will be the measurement of the height of the tube in a direction that is perpendicular to the surface of the outer support surface 422.
FIGS. 12 through 15 show various illustrative examples of supports having different material and/or physical characteristics. FIG. 12 shows an illustrative example of the support 518 having an inner layer 532 sandwiched between a pair of outer layers 534a, 534b. The inner layer 532 has maximum radial crush strength that is greater than the maximum radial crush strength of that of the outer layers 534a, 534b, which means that the inner layer 532 will retain its shape and will not undergo deformation when the outer layers 534a, 534b of the support 518 are deformed. This enables the depth of deformation of the outer layers 534a, 534b of the support 509 to be consistent even if there are variations in the normal force applied to the tubes 506a-f and/or if there are variations in the radial crush strength of the outer layers 534a, 534b. In some examples, the outer layers 534a, 534b are made of a different material than the inner layer 532, whereby the material of the inner layer 532 has a greater maximum radial crush strength than that of the material of the outer layers 534a, 534b. In another example in which the inner layer 532 and outer layers 534a, 534b are made of the same material, particularly a hollow cell material, the outer layers 534a, 534b may include open cells while the inner layer 532 includes closed cells. In yet another example, the inner layer 532 and outer layers 534a, 534b can all include combinations of closed and open cells, whereby the inner layer 532 includes a greater number of closed cells than the outer layers 534a, 534b, in order to ensure that the maximum radial crush strength of inner layer 532 is greater than that of the outer layers 534a, 534b. In this embodiment, the inner layer 532 can function as a spacer element, such that the spacer is integral to the support 518. This allows the support 518 to accomplish the spacing function which in other examples would be provided by a separate spacer. In other words, each support 518 is also a spacer.
FIG. 13 shows an illustrative example of a support 518 that includes partially defined recesses 636a-f. The partially defined recesses 636a-f are configured to receive at least a portion of the tubes 606a-f of each of the tube layers 612, 614 prior to the outer support surface 622 of the support 618 undergoing deformation. The partially defined recesses 636a-f are smaller in size than the resulting tube seat recess that is formed after deformation of the outer support surface 622 of the support 618. The partially defined recesses 606a-f and are adapted to assist in aligning the tubes 606a-f to the desired position and vertical spacing prior to the deformation step that forms the tube seat recesses. In the illustrative example, the partially defined recesses 636a-f are disposed on opposing first and second sides 636, 638 of the support 618. In other examples, the partially defined recesses 636a-f may be disposed on only one of the first side 636 or second side 638 of the support 618. After the outer support surface 622 of the support 618 is deformed, the partially defined recesses 636a-f increase in size to form the tube seat recesses.
FIG. 14 shows an illustrative example of a support 718, whereby an outer support surface 722a along a first side 736 of the support 718 is configured to be deformed. In this illustrative example, the support 718 is configured such that the maximum radial crush strength of the outer support surface 722a along the first side 736 of the support 718 is less than the maximum radial crush strength of the outer support surface 722b along the second side 738 of the support 718. Similar to the inner and outer support layers of the example support shown in FIG. 13, FIG. 14 shows the first side 736 and second side 738 of the support 718 comprising different materials with different maximum radial crush strengths. In another example, the first side 736 and second side 738 of the support 718 may include the same material with different combinations of open and closed cells to achieve the desired difference in maximum radial crush strength between the outer support surface 722a of the first side 736 of the support 718 and the outer support surface 722b of the second side 738 of the support 718. In this illustrative example, the outer support surface 722a along the first side 736 of the support 718 is configured to be deformed while the outer support surface 722b along the second side 738 of the support 718 retains its original shape and profile both during and after the deformation of the outer surface 722a of the first side 736 of the support 718. In this example, the non-deformable second side 738 of the support 718 can function as a spacer element, such that the spacer element is integral to the support 718. Similar to the example shown in FIG. 12, this allows the support 718 to accomplish the spacing function which in other examples would be provided by a separate spacer.
FIG. 15 shows an illustrative example of a support 818, whereby an outer support surface 822a along a first side 836 of the support 818 is configured to be deformed. In this illustrative example, the support 818 is configured such that the maximum radial crush strength of the outer support surface 822a along the first side 836 of the support 818 is less than the maximum radial crush strength of the outer support surface 822b along the second side 838 of the support 818. Similar to FIG. 14, FIG. 15 shows the first side 836 and second side 838 of the support 818 comprising different materials with different maximum radial crush strengths. In another example, the first side 836 and second side 838 of the support 818 may include the same material with different combinations of open and closed cells to achieve the desired difference in maximum radial crush strength between the outer support surface 822a of the first side 836 of the support 818 and the outer support surface 822b of the second side 838 of the support 818. In this illustrative example, the outer support surface 822a along the first side 836 of the support 818 is configured to be deformed while the outer support surface 822b along the second side 838 of the support 818 retains its original shape and profile both during and after the deformation of the outer surface 822a of the first side 836 of the support 818. In this example, the non-deformable second side 838 of the support 818 can function as a spacer element, such that the spacer element is integral to the support 818. Similar to the examples shown in FIG. 12 and FIG. 14, this allows the support 818 to accomplish the spacing function which in other examples would be provided by a separate spacer. In this illustrative example, the non-deformable second side 838 of the support 818 includes tube seats 846a-c which are configured to receive at least a portion of the tubes 806a-f of at least one of the tube layers 812, 814 prior to the outer support surface 822b along the second side 838 of the support 818 is being deformed. The tube seats 846a-c help to secure at least one of the tube layers 812, 814 in place and allow for different spacing configurations to be achieved.
FIG. 16 shows an exemplary method of forming a tube bundle for a CWHE using deformable supports, such as those described above and shown in previous figures. The exemplary method includes providing a mandrel which extends along a mandrel longitudinal axis, an illustrative example of which is shown in FIG. 1-3 (step 1050). A support layer is formed by placing a plurality of spacers and supports against the mandrel (step 1051). Then a first tube layer is formed by winding at least one tube around the mandrel (step 1052). Supports and spacers are then placed on the outer surface of the first tube layer (step 1054) and a second tube layer is formed by winding at least one tube around the mandrel and over the spacers and supports (step 1056). A deforming force, having a component that is normal to the outer surface of each of the plurality of first layer supports, is applied to the second tube layer (step 1058). The deforming force may comprise tension on the tube as a result of the winding process and/or an additional force, such as a roller that closely follows the winding of the tube. The application of the deforming force is sufficient to cause the tubes to deform the support so that each tube in the first and second tube layers is in a recessed position relative to the initial position of the support outer surface. Steps 1052 through 1058 may be repeated for each additional layer that is added to the tube bundle.
As such, an invention has been disclosed in terms of preferred embodiments and alternate embodiments thereof. Of course, various changes, modifications, and alterations from the teachings of the present invention may be contemplated by those skilled in the art without departing from the intended spirit and scope thereof. It is intended that the present invention only be limited by the terms of the appended claims.
Patent Application
20250108429
