Heat pipe wick fabrication using in-situ rolling and hydroforming equipment

Abstract

An in-situ wick rolling and forming assembly configured to roll and form a heat pipe wick from a wick mesh. The in-situ wick rolling and forming assembly includes a first forming shell, a grooved mandrel, and an expandable member. The first forming shell is configured to form the wick in-situ after rolling the wick mesh. The first forming shell includes a first recess and a first parting surface. A first central axis of the first recess is located below the first parting surface. The grooved mandrel is removably positioned within the first recess.

Description

[Technical Field]

[0001] (Government Contract) This invention was made with government support under Contract DE-NE-0009050 awarded by the Department of Energy. The government has certain rights in this invention.

[0002] (CROSS-REFERENCE TO RELATED APPLICATIONS) This application claims the benefit of and priority under 35 U.S.C. §119(e) to U.S. patent application Ser. No. 63 / 380,329, filed October 20, 2022, entitled "MANUFACTURE OF HEAT PIPE WICKS UTILIZING IN-SITU ROLLING AND HYDROFORMING DEVICE," the contents of which are incorporated herein by reference in their entirety. [Background technology]

[0003] The present invention relates generally to heat pipes used in heat transfer systems, and more particularly to a wick within a heat pipe configured to move the working fluid of the heat pipe from a condensation region to an evaporation region of the heat pipe.

[0004] A heat pipe is a sealed, two-phase heat transfer component used to transfer heat from a primary side (evaporation section) to a secondary side (condensation section). FIG. 1 illustrates an example heat pipe 100, including an evaporator section 102, a condenser section 106, and an adiabatic section 104 extending therebetween. The heat pipe 100 further includes a working fluid (e.g., water, liquid potassium, sodium, or an alkali metal) and a wick 108. During operation, the working fluid absorbs heat and vaporizes in the evaporator section 102. Saturated vapor with latent heat of vaporization flows through the adiabatic section 104 toward the condenser section 106. In the condenser section 106, the vapor condenses into a liquid pool 110, releasing the latent heat. The condensed liquid is returned to the evaporator section 102 through the wick 108 by capillary action. The flow path of the working fluid is indicated by several divided arrows in FIG. 1. The phase change process and two-phase circulation continue as long as the temperature gradient between the evaporator section and the condenser section is maintained. Because the heat transfer coefficients for boiling and condensation are so high, heat pipes are very efficient heat conductors.

[0005] Nuclear systems utilize heat pipes by placing the evaporator section within the reactor core containing the nuclear fuel and the condenser section adjacent to a heat exchanger. The nuclear fuel vaporizes the working fluid, and the heat exchanger absorbs the latent heat in the condenser section. Examples of heat pipes in nuclear applications are described in U.S. Pat. No. 5,684,848, U.S. Pat. No. 6,768,781, and U.S. Patent Application Publication No. 2016 / 0027536, all of which are incorporated by reference in their entireties.

[0006] Another use of heat pipes in nuclear systems is in microreactors. Microreactors are nuclear reactors that produce less than 10 MWe and can be installed in remote applications. Such microreactors are housed in relatively small vessels, can operate without active human intervention, and can operate without refueling / replacement for longer periods than conventional nuclear power plants. One such microreactor is the eVinci microreactor system designed by Westinghouse Electric Company. The eVinci system is a heat-pipe-cooled nuclear power system that uses heat pipes as passive heat removal devices to efficiently transfer thermal energy from the reactor core to a heat exchanger.

[0007] Heat pipes used in microreactors are exposed to extreme operating temperatures (over 850°C) and require an internal wick made of a material that can withstand these temperatures and is compatible with the working fluid. This wick can be fabricated from a wire mesh that is rolled and diffusion bonded into a tube. The wick tube allows the working fluid in the heat pipe to flow radially (after latent heat is released and the working fluid is absorbed by the wick) and axially (capillary action moves the working fluid back toward the evaporation section) while the wick tube remains rigid.

[0008] The manufacture of wicks for insertion into heat pipes requires a highly complex and detailed process. At a very high level, wicks are manufactured by rolling a woven sheet of wick mesh material into the desired shape, compressing a material (such as a tube) onto the wick to force it into the desired shape, diffusion bonding the mesh in a vacuum-level oven while maintaining the wick in compression, and then removing the material used to hold the wick in compression during the diffusion bonding process. An example of such a wick-forming method is described in U.S. Pat. No. 3,964,902, entitled "METHOD OF FORMING A WICK FOR A HEAT PIPE," which is incorporated herein by reference.

[0009] As mentioned above, current methods for forming wicks require that the material used to hold the wick in a compressed state be removed after the diffusion bonding process. As an example, U.S. Patent No. 3,964,902 describes a method that uses copper inner and outer mandrels to compress the wick, and then requires chemical removal of the inner and outer mandrels after diffusion bonding using a chemical etching technique. However, subjecting the wick to this chemical etching process introduces impurities into the wick, reducing its intended functionality. Additionally, the chemical etching technique increases the time and costs associated with manufacturing the wick.

[0010] An object of the disclosure is to provide an assembly and method for rolling and forming a wick in a single device, thereby eliminating the need to transfer the rolled wick between rolling and forming devices, thus reducing the cost and time required to manufacture the wick over other known methods. Summary of the Invention

[0011] In various embodiments, an in-situ wick rolling and forming assembly is configured to roll and form a heat pipe wick from a wick mesh. The in-situ wick rolling and forming assembly includes a first forming shell, a grooved mandrel, and an expandable member. The first forming shell is configured to roll the wick mesh and then form the wick in situ. The first forming shell includes a first recess and a first parting surface. A first central axis of the first recess is located below the first parting surface. The grooved mandrel is removably positionable within the first recess. The grooved mandrel includes a first end, a second end, an elongated body, and a groove. The elongated body is between the first and second ends and defines a longitudinal axis. The groove extends along the longitudinal axis and is configured to receive a leading edge of the wick mesh. The expandable member is fluidly expandable to an expanded configuration. The expandable member is removably positionable within the grooved mandrel. The expandable member is configured, in the expanded configuration, to contact a leading edge of the wick mesh such that the leading edge of the wick mesh is gripped between the grooved mandrel and the expandable member, and the grooved mandrel is rotatable about a longitudinal axis relative to the first recess to wrap the wick mesh around an outer surface of the grooved mandrel.

[0012] In various embodiments, a method for in-situ rolling and forming a heat pipe wick from a wick mesh is disclosed. The method includes threading a wick mesh through a tensioner toward a first forming shell of an in-situ wick rolling and forming assembly, positioning a grooved mandrel of the in-situ wick rolling and forming assembly into a first recess of the first forming shell, gripping a leading edge of the wick mesh between the grooved mandrel and an expandable member disposed inside the grooved mandrel, rotating the grooved mandrel multiple times relative to the first forming shell about a longitudinal axis defined through the grooved mandrel to form a rolled wick mesh, contracting the expandable member to release the leading edge of the wick mesh, removing the grooved mandrel and the expandable member from the first forming shell, positioning an expandable tube in-situ inside the rolled wick mesh, securing a second forming shell relative to the first forming shell, and expanding the expandable tube to permanently deform the rolled wick mesh against the interior surfaces of the first and second forming shells. [Brief explanation of the drawings]

[0013] The various features of the embodiments described herein, together with their advantages, may be understood as follows from the following description taken in conjunction with the accompanying drawings.

[0014] [Figure 1] 1 is a diagram showing a working fluid moving through a heat pipe.

[0015] [Figure 2] 1 illustrates a rolling assembly according to at least one aspect of the present disclosure.

[0016] [Figure 3] FIG. 1 is a front view of a grooved mandrel according to at least one aspect of the present disclosure.

[0017] [Figure 4]FIG. 2 is a front view of a first molded shell according to at least one embodiment of the present disclosure.

[0018] [Figure 5] FIG. 10 is a front view of a second molded shell according to at least one embodiment of the present disclosure.

[0019] [Figure 6] 1 illustrates a molding assembly according to at least one aspect of the present disclosure.

[0020] [Figure 7] FIG. 7 is an exploded view of the molding assembly of FIG. 6 according to at least one embodiment of the present disclosure.

[0021] [Figure 8] FIG. 8 is a close-up view of an end flange, fastener, and O-ring of the molding assembly of FIG. 7, according to at least one embodiment of the present disclosure.

[0022] [Figure 9] 8 is a close-up view of the expandable tube and wick mesh of the molding assembly of FIG. 7, according to at least one embodiment of the present disclosure.

[0023] [Figure 10] FIG. 7 illustrates a first end flange of the molding assembly of FIG. 6, according to at least one embodiment of the present disclosure.

[0024] [Figure 11] FIG. 11 is a cross-sectional view of the first end flange of FIG. 10 according to at least one embodiment of the present disclosure.

[0025] [Figure 12] FIG. 7 is a front view of the molding assembly of FIG. 6, according to at least one embodiment of the present disclosure.

[0026] [Figure 13] 13 shows a cross-sectional view of the molding assembly of FIG. 12 according to at least one embodiment of the present disclosure.

[0027] [Figure 14] FIG. 10 is a detailed view of an expandable tube and wick mesh inserted into a receiving area of ​​a first end flange, according to at least one embodiment of the present disclosure.

[0028] [Figure 15] FIG. 10 is a detailed view of an expandable tube and wick mesh inserted into a receiving area of ​​a second end flange, according to at least one embodiment of the present disclosure.

[0029] [Figure 16] 1A-1C illustrate a method of in situ wick rolling and forming a heat pipe wick from a wick mesh, according to at least one embodiment of the present disclosure.

[0030] [Figure 17] 1 illustrates a tensioner according to at least one aspect of the present disclosure.

[0031] Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set forth herein are, in one aspect, illustrative of various embodiments of the invention, and such exemplifications are not to be construed as limiting the scope of the invention in any manner. DETAILED DESCRIPTION OF THE INVENTION

[0032] Certain specific details are set forth to provide a thorough understanding of the overall structure, function, manufacture, and use of the embodiments described herein and illustrated in the accompanying drawings. Well-known operations, components, and elements have not been described in detail so as not to obscure the embodiments described herein. The reader can understand that the embodiments described and illustrated herein are non-limiting examples, and thus, the specific structural and functional details disclosed herein may be representative and exemplary. Variations and modifications may be made without departing from the scope of the claims.

[0033] 2 illustrates a rolling assembly 201 for rolling a wick 108, according to at least one embodiment of the present disclosure. A sheet or sheets of wick mesh 204 are configured to be tightly rolled or wrapped into a predetermined shape around a grooved mandrel 210. In at least one embodiment, the grooved mandrel 210 is constructed of stainless steel.

[0034] Further to the above, the wick rolling assembly 201 includes a grooved mandrel 210 configured to be placed in and subsequently removed from a first recess 232 in a lower or first forming shell 230. As shown in FIG. 3, the grooved mandrel 210 can be a tube having a groove 214 extending axially 212 along its length. The groove 214 is configured to receive the leading edge of the wick mesh 204. Thus, a sheet of wick mesh 204, which can be cut to size prior to rolling, can be rolled into place around the grooved mandrel 210 before being formed into the final wick shape. Because the grooved mandrel 210 is used to roll the wick 108, the outer diameter of the grooved mandrel 210 will define the inner diameter of the rolled wick 108 prior to the forming process. The wick mesh 204 is rolled to the desired outer diameter, with the corresponding number of mesh turns defining the thickness of the rolled wick.

[0035] Referring again to FIG. 2 , the inner diameter of the grooved mandrel 210 is configured to receive the expandable member 222. The expandable member 222 must be longer in length than the lower molding shell 230 and the grooved mandrel 210 so that it extends from the mandrel end 218 when attached. In various examples, the expandable member 222 defines an inflatable bladder. The expandable member 222 is changeable from an expanded position to a contracted position. When in the contracted, or at least partially contracted, position, the expandable member 222 can be slid through the mandrel end 218 and into the inner diameter of the grooved mandrel 210. The expandable member 222 can then be expanded to the expanded position using any suitable fluid, such as, but not limited to, air or water. In the expanded position, the expandable member 222 can provide a gripping or clamping force such that when the leading edge of the wire mesh 204 is placed in the groove 214 of the grooved mandrel 210, the leading edge of the wire mesh 204 is tightly gripped between the inner diameter of the grooved mandrel 210 and the outer diameter of the expandable member 222. Depending on the thickness of the wire mesh 204, the expandable member 222 can be inflated to various pressures to create the required gripping strength. The expandable member 222 can be made of any suitable material, such as, by way of example, rubber. The material of the expandable member 222 is selected so that it can maintain its shape under constant pressure during the rolling process and contract when the pressure is released. In at least one embodiment, the expandable member 222 comprises a soft rubber tube.

[0036] The wick rolling assembly 201 may also include a lower or first forming shell 230, which may provide the outer shape and dimensions of the wick mesh 204 as it is rolled inside the first forming shell 230. As shown in FIG. 4 , the first forming shell 230 includes a first cavity, or recess 232, and a first parting surface 234 extending from an end of the first forming recess 232. The first recess 232 and the first parting surface 234 are defined within the first forming shell 230 and extend along its length. A central axis 236 of the first recess 232 is positioned below the first parting surface 234 such that the first recess 232 of the first forming shell 230 holds the rolled wick mesh 204 in place, i.e., in a rolled state, even after the grooved mandrel 210 is removed from the rolled wick mesh 204. In the illustrated embodiment, the central axis 236 of the first molding recess 232 lies below an axis 237 that intersects both ends of the first recess 232 .

[0037] The first parting surface 234 of the first forming shell 230 may be flat or angled. In the illustrated embodiment, the first parting surface 234 includes angled portions 234a and 234b extending from the ends of the first recess 232 and flat portions 234c and 234d extending from the angled portions 234a and 234b, respectively, as shown in FIG. 4 . In the illustrated embodiment, the angled portions 234a and 234b are angled upwardly away from the first recess 232 and define an acute angle with the axis 237. This profile minimizes the number of sharp angles that the wick mesh 204 must traverse during the wick rolling process, thereby minimizing the number of potential snag points on which the wick mesh 204 may become stuck, improving the durability of the first forming shell 230.

[0038] The wick rolling assembly 201 may also include a top, or second, forming shell 240 that cooperates with the first forming shell 230 to provide the outer shape and dimensions of the wick mesh 204 during the forming process, as described in more detail below. As shown in FIG. 5, the second forming shell 240 includes a second cavity or recess 242 and a second parting surface 244 extending from an end of the second forming recess 242. The second recess 242 and the second parting surface 244 are defined within the second forming shell 240 and extend along its length. A central axis 246 of the second recess 242 is located below the first parting surface 234.

[0039] The second parting surface 244 of the first molded shell 240 may be flat or angled. In the illustrated embodiment, the second parting surface 244 includes angled portions 244a and 244b extending from the ends of the second recess 242 and flat portions 244c and 244d extending from the angled portions 244a and 244b, respectively, as shown in FIG. 4. In the illustrated example, the angled portions 244a and 244b define an acute angle with the axis 239 that intersects the ends of the second recess 242.

[0040] The profile of the second parting surface 244 is complementary to the shape of the first parting surface 234, allowing for intimate contact between the shells 230, 240 during the molding process, as described in more detail below. When the shells 230, 240 are assembled, the recesses 232, 242 cooperate to define a cylindrical surface around the rolled wick mesh. In the illustrated example, the first recess 232 defines approximately two-thirds of the cylindrical surface, and the second recess 242 defines approximately one-third of the cylindrical surface. In certain embodiments, the first recess 232 defines a larger portion of the cylindrical surface than the second recess 242.

[0041] The wick rolling assembly 201 may further include a tensioner 400, as shown in FIG. 17 . The wick mesh 204 may be fed through the tensioner 400 before the leading edge of the wick mesh 204 is inserted into the grooved mandrel 210. The tensioner 400 may include a roller 403 and a bridge 404, which may be raised or lowered to allow the wick mesh 204 to be inserted between the roller 403 and the bridge 404. The bridge 404 may further include one or more tension members 402 for applying a constant downward force to the wick mesh 204 when the bridge 404 is in the lowered position. The tension member 402 may be spring-biased, for example, toward the roller 403. Thus, the tensioner 400 may hold the wick mesh 204 and apply a backward force from the rolling direction as the wick mesh 204 is rolled. This prevents the wick mesh 204 from twisting and being unevenly fed into the wick rolling assembly 201. The tensioner 400 can be made of any suitable material, such as, for example, T-slot extruded aluminum. The tensioner 400 can be spatially separate from the wick rolling assembly 201 or can be integral with the wick rolling assembly 201.

[0042] 2, the grooved mandrel 210 can be slidably inserted into the first recess 232 of the lower forming shell 230. Separately, a compression sleeve 220 can be attached to the mandrel end 218. The mandrel end 218 with the compression sleeve 220 attached can then be attached to one end of the grooved mandrel 210. The expandable member 222 is then placed into the grooved mandrel 210 through the mandrel end 218. The wick mesh 204 should be rolled in a manner that avoids pinching the wick mesh 204 at the first parting surface 234 of the first forming shell 230. In at least one embodiment, the leading end of the wick mesh 204 is threaded over one of the first ends of the first recesses 232 and then inserted into the second end for winding.

[0043] FIG. 6 illustrates a molding assembly 202 for molding a wick according to at least one embodiment of the present disclosure. FIG. 7 illustrates an exploded view of the molding assembly 202. With particular reference to FIGS. 7 and 9, the molding assembly 202 can include an expandable or inflatable tube 248 that is transitionable between an unexpanded or contracted configuration and a hydraulically expanded or inflated configuration. The expandable tube 248 can be made from any suitable material, such as, by way of example, polyurethane. The material of the expandable tube 248 is selected so that, when the wick mesh 204 is molded into the wick, the expandable tube 248 does not substantially stick, adhere, or leave substantial traces on the wick to an extent that would compromise the wick's composition, structural integrity, and / or shape, as described in more detail below.

[0044] The examples provided in connection with Figures 6 and 7 are designed to obtain a tubular wick by utilizing an expandable tube 248. However, this is not intended to be limiting. Other wick designs are contemplated by the present disclosure, such as wicks having a pentagonal, hexagonal, heptagonal, octagonal, or any suitable polygonal cross section. In such embodiments, geometrically appropriate expandable and support housings may be utilized.

[0045] 9, the length of the sheet of wick mesh 204 is configured to be cut shorter than the length of the expandable tube 248 such that an untrapped zone 208 is defined between the end of the sheet of wick mesh 204 and the end of the expandable tube 248. Other embodiments are envisioned in which the wick mesh 204 is not cut shorter such that the lengths of the expandable tube 248 and the wick mesh 204 are the same, or at least substantially the same.

[0046] 6 and 7, the forming assembly 202 may further include a forming shell assembly 228. The forming shell assembly 228 includes a lower or first forming shell 230 and an upper or second forming shell 240. Each of the first forming shell 230 and the second forming shell 240 may be made from any suitable solid material, such as, by way of example, stainless steel. In one embodiment, the forming shells 230, 240 may be made from the same material as the material of the wick mesh 204. Each of the first forming shell 230 and the second forming shell 240 includes a cavity, or recess 232, 242, defined therein that extends along its length. The recesses 232, 242 in the molded shells 230, 240 are complementarily configured such that when the first molded shell 230 and the second molded shell 240 are brought together, the recesses 232, 242 cooperate to define a receiving area configured to receive the rolled wick mesh 204, as seen in Figures 14 and 15. The recesses 232, 242 are sized such that when brought together, there is a gap between the wick mesh 204 and each of the recesses 232, 242.

[0047] The recesses 232, 242 in the first and second forming shells 230, 240 are configured to provide a solid surface and a boundary for maximum deformation for the sheet(s) of wick mesh 204. The recesses 232, 242 are configured to act on the sheet of wick mesh 204 that is rolled around the expandable tube 248 as the expandable tube 248 is hydraulically expanded to its expanded configuration. The recesses 232, 242 are configured to define the outer diameter and final shape of the wick. In one embodiment, the recesses 232, 242 have a partial circular cross-sectional shape with a radius of curvature such that when the first and second forming shells 230, 240 are abutted, the partial circular recesses 232, 242 form a circular shape along the entire length of the forming shell assembly 228, as shown, by way of example, in FIGS. 4 and 5 . Other embodiments are contemplated in which the recesses 232, 242 in each molding shell 230, 240 have other complementary shapes so that when the first molding shell 230 and the second molding shell 240 are brought together, the recesses 232, 242 cooperate to form other shapes, such as an oval, a square, or other symmetrical shape desired for the wick. As another example, it is contemplated that the recesses 232, 242 in each molding shell 230, 240 are dissimilar to the other so that when the first molding shell 230 and the second molding shell 240 are brought together, a wick with an asymmetrical shape can be formed. The recesses 232, 242 can be shaped to allow for any desired wick shape.

[0048] 7 , the molded shell assembly 228 may further include a first end flange 262 and a second end flange 264. The first end flange 262 and the second end flange 264 are configured to be fastened to the ends of the first molded shell 230 and the second molded shell 240 by a plurality of fasteners 272. In one embodiment, the fasteners 272 may comprise bolts configured to be threadably received in threaded openings defined in the first molded shell 230 and the second molded shell 240. While the fasteners 272 are shown and described, other suitable methods for coupling the end flanges 262, 264 to the first and second molded shells 230, 240 are envisioned, such as using latching mechanisms, adhesives, or clamps, by way of example.

[0049] As shown in Figures 10, 11, and 14, the first end flange 262 includes a wick assembly receiving area 276, a groove 268 extending around the wick assembly receiving area 276, and hydraulic openings 266. As described above, the length of the sheet of wick mesh 204 is configured to be cut shorter than the length of the expandable tube 248 so that an untrapped zone 208 is defined between the end of the sheet of wick mesh 204 and the end of the expandable tube 248. A portion of the untrapped zone 208 is configured to be received by the wick assembly receiving area 276 of the first end flange 262. Furthermore, an O-ring 270 is configured to be disposed within the groove 268 such that the O-ring 270 is disposed around a portion of the untrapped zone 208. The combination of the O-ring 270 and the untrapped zone 208 within the wick assembly receiving area 276 forms a seal within the molded shell assembly 228. 15, the second end flange 264 is substantially similar to the first end flange 262. Other embodiments are contemplated in which only the first end flange 262 or the second end flange 264 includes hydraulic openings 266.

[0050] Hydraulic openings 266 in first end flange 262 and second end flange 264 are configured to interface with a hydraulic source, such as a water source, an air source, or any other suitable hydraulic source, configured to apply pressure to expandable tube 248 through hydraulic openings 266 to transition expandable tube 248 to the expanded configuration.

[0051] As described above, a portion of the untrapped zone 208 of the wick molding assembly 202 is configured to be inserted through the wick assembly receiving area 276 and O-ring 270 of the first end flange 262 and second end flange 264 to form a seal. This seal allows for internal pressurization of the expandable tube 248 via a hydraulic pressure source. The seal also prevents fluid from escaping or leaking from the molded shell assembly 228 and prevents hydraulic fluid from contacting the wick mesh 204 around the inflatable tube 248. Additionally, as described above, the length of the sheet of wick mesh 204 is configured to be cut shorter than the length of the expandable tube 248 to prevent the wick mesh 204 from expanding over uneven surfaces of the first end flange 262 and second end flange 264, such as the wick assembly receiving area 276 or groove 268.

[0052] 6 and 7, the mold assembly 202 can include a pressure plate assembly 250. The pressure plate assembly 250 can include a first pressure plate 252 and a second pressure plate 254. The first pressure plate 252 is configured to abut the first mold shell 230, the first end flange 262, and the second end flange 264. The second pressure plate 254 is configured to abut the second mold shell 240, the first end flange 262, and the second end flange 264. Other embodiments are contemplated in which the pressure plates 252, 254 only contact the mold shells 230, 240 and not the end flanges 262, 264. A plurality of fasteners 256 can be configured to fasten the first pressure plate 252 to the second pressure plate 254. The pressure plate assembly 250 can be sized to accommodate any number of mold shell assemblies.

[0053] The pressure plate assembly 250 is configured to apply a preload to the forming shell assembly 228 so that when a pressure source hydraulically expands the expandable tube 248 and wick mesh 204 into contact with the recesses 232, 242 in the forming shells 230, 240, the forming shells 230, 240 remain compressed together with no separation therebetween. In one embodiment, the plurality of fasteners 256 may comprise bolts, nuts, and washers, as shown in FIG. 7. Other means for preventing the first and second forming shells 230, 240 from separating are contemplated by the present disclosure in place of the pressure plate assembly 250, including, for example, a latch assembly, a plurality of clamps, or any other suitable means for preventing the first and second forming shells 230, 240 from separating during pressurization of the expandable tube 248.

[0054] Pressure plate assembly 250 is configured to provide additional structural rigidity to forming shell assembly 228 to minimize deformation upon pressurization of expandable tube 248. A plurality of fasteners 256 along the length of pressure plate assembly 250 can be configured to center forming shell assembly 228 within pressure plate assembly 250. In one embodiment, pressure plate assembly 250 could include a groove that serves as a centering feature for forming shell assembly 228. The thickness and overall dimensions of first pressure plate 252 and second pressure plate 254 can be varied to allow for higher internal molding pressures experienced by expandable tube 248.

[0055] The in-situ rolling mold assembly 200 is designed with features that allow for easy and convenient assembly / disassembly. After the wick 108 has been molded and the mold assembly 202 has been depressurized, the in-situ rolling mold assembly 200 can be disassembled by loosening or removing the fasteners 256 on the pressure plate assembly 250, allowing the molded shell assembly 228 to be pushed out from between the pressure plates 252, 254. The second pressure plate 254 includes hooks 274 that aid in the placement and removal of the second pressure plate 254, thereby facilitating access to the molded shell assembly 228. The first and second end flanges 262, 264 are then removed by removing the associated fasteners 272. The design of the O-ring 270 allows the flanges 262, 264 to slip out of the uncaptured zone 208 of the expandable tube 248. As mentioned above, the wick mesh 204 remains deformed after the molding process, allowing the expandable tube 248 to transition to an unexpanded configuration and separate from the wick 108. The space between the expandable tube 248 and the wick 108 allows the expandable tube 248 to be easily removed. The upper and lower molded shells 230, 240 can then be separated, and the wick 108 can be removed.

[0056] The molding assembly and associated procedures described above have been tested and certified to produce wicks with the proper dimensions (outer diameter, thickness), tolerances (approximately ±0.001 inches diameter), pore size, and strength required for use in heat pipes after diffusion bonding. Additionally, the molding assembly and associated steps have proven highly repeatable through multiple tests.

[0057] In one embodiment, the in-situ rolling forming assembly 200 can be configured to produce a one-foot length of wick with a specified diameter and thickness (based on the predefined dimensions of the recesses 232, 242 and the selected number of layers of the wick mesh 204). The design of the in-situ rolling forming assembly 200 may be used to produce a continuous assembly to produce different lengths (as described in more detail herein), or may be slightly modified to be assembled in segments. By utilizing the forming assembly described above and varying the dimensions of the recesses 232, 242, the length of the forming shell assembly 228, and the number of layers of the wick mesh 204, any length, diameter, and thickness of formed wick 108 is possible.

[0058] The outer diameter of the final wick is determined by the recess in the molded shell, so by varying the size and shape of the recess, molded wicks of various sizes and shapes can be produced, as described above.

[0059] 16, a method 300 for in-situ wick rolling and forming a heat pipe wick from a wick mesh is illustrated in accordance with at least one embodiment of the present disclosure. In various embodiments, one or more aspects of the method 300 can be implemented using one or more of the apparatus, systems, or components of the present disclosure. The method 300 includes threading the wick mesh through a tensioner toward a first forming shell of an in-situ wick rolling and forming assembly (302), positioning a grooved mandrel of the in-situ wick rolling and forming assembly into a first recess of the first forming shell (304), gripping a leading edge of the wick mesh between the grooved mandrel and an expandable member disposed within the grooved mandrel (306), and rotating the grooved mandrel multiple full revolutions relative to the first forming shell about a longitudinal axis defined through the grooved mandrel to form the rolled wick. The method includes shaping the rolled wick mesh (308), contracting the expandable member to release the leading edge of the wick mesh (310), removing the grooved mandrel and inflatable member from the first forming shell (312), placing the expandable tube in situ inside the rolled wick mesh (314), securing the second forming shell relative to the first forming shell (316), and expanding the expandable tube to permanently deform the rolled wick mesh against the inner surfaces of the first and second forming shells (318).

[0060] In certain embodiments, the grooved mandrel and / or expandable member are removed from the first forming shell by withdrawing them without disturbing the rolled wick mesh. The grooved mandrel and / or expandable member can be withdrawn while the wick mesh remains over the recess in the first forming shell. In certain embodiments, the expandable tube is placed inside the rolled wick mesh in situ by sliding the expandable tube through the opening in the rolled wick mesh.

[0061] Further, in certain examples, a method (e.g., method 300) includes expanding the expandable tube using a pressurized fluid that forces the wick mesh material outward until it contacts the hydroforming upper and lower capture dies, causing compression and eventual permanent deformation of the wick mesh material. In certain embodiments, a method (e.g., method 300) includes producing a permanently deformed cylindrical wick comprising an outer diameter that matches the inner diameter of the hydroforming upper and lower capture dies and a thickness determined by the number of wire mesh layers. In certain embodiments, a method (e.g., method 300) includes producing a permanently deformed cylindrical wick comprising a uniform pore size confirmed by a bubble test.

[0062] In certain embodiments, a method (e.g., method 300) includes separating the expandable tubing from the permanently deformed mesh after depressurization, allowing for manual removal of the expandable tubing from the hydroformed wick without damaging the hydroformed wick. Hydroformed wicks are suitable for diffusion bonding at high temperatures (>900°C) without the need for fixtures to hold and secure them in place during diffusion bonding.

[0063] Unless otherwise specifically stated as is apparent from the foregoing disclosure, throughout the foregoing disclosure, discussions using terms such as "processing," "computing," "calculating," "determining," "displaying," and the like will be understood to refer to operations and processes of a computer system or similar electronic computing device that manipulate and transform data represented as physical (electronic) quantities in the computer system's registers and memory into other data similarly represented as physical quantities in the computer system's memory or registers or other information storage, transmission, or display devices.

[0064] One or more components may be referred to herein as being "configured to," "configurable to," "operable to," "adapted to," "capable of," "adaptable to," "adaptable to," etc. Those skilled in the art will recognize that, unless the context requires otherwise, "configured to" may generally encompass active and / or inactive and / or standby components.

[0065] Those skilled in the art will generally recognize that terms used in this specification, and particularly in the appended claims (e.g., the body of the appended claims), are generally intended as "open" terms (e.g., the term "comprises" should be interpreted as "including, but not limited to," the term "having" should be interpreted as "having at least," the term "comprises" should be interpreted as "including, but not limited to," etc.). Those skilled in the art will further understand that if a specific number of recitations of an introduced claim are intended, such intention will be explicitly set forth in the claim; otherwise, no such intention exists. For example, as an aid to understanding, the appended claims below may use the introductory phrases "at least one" and "one or more" to introduce the recitations of the claims. However, the use of such phrases should not be construed as meaning that the introduction of a claim recitation by the indefinite article "a" or "an" limits a particular claim that includes such introduced claim recitation to claims that include only one such introduced claim recitation, even if that same claim includes the introductory phrase "one or more" or "at least one" and an indefinite article such as "a" or "an" (e.g., "a" and / or "an" should ordinarily be construed to mean "at least one" or "one or more").

[0066] Furthermore, even when a specific number in an introduced claim is explicitly recited, those skilled in the art will recognize that such recitation should generally be interpreted to mean at least the recited number (e.g., the recitation "two items" without other modifiers generally means at least two items, or more than two items). Furthermore, when a conventional description similar to "at least one of A, B, and C, etc." is used, such a configuration is generally intended in the sense that those skilled in the art would understand the conventional description (e.g., "a system having at least one of A, B, and C" includes, but is not limited to, systems having A alone, B alone, C alone, A and B together, A and C together, B and C together, and / or A, B, and C together, etc.). When a conventional description similar to "at least one of A, B, or C, etc." is used, such a configuration is generally intended in the sense that one of ordinary skill in the art would understand the conventional description (e.g., "a system having at least one of A, B, or C" includes, but is not limited to, a system having A alone, B alone, C alone, A and B together, A and C together, B and C together, and / or A, B, and C together, etc.). As will be further understood by one of ordinary skill in the art, whether in the specification, claims, or drawings, disjunctive words and / or phrases that typically present two or more alternative terms should be understood to contemplate the possibility of including one of the terms, either of the terms, or both terms, unless the context dictates otherwise. For example, the phrase "A or B" is typically understood to include the possibilities of "A" or "B" or "A and B."

[0067] With respect to the appended claims, those skilled in the art will understand that the operations described therein may generally be performed in any order. Also, while various operational flow diagrams are shown in a sequence, it should be understood that various operations may be performed in an order other than that shown, or may be performed simultaneously. Examples of such alternative sequences may include overlapping, alternating, interrupted, reordered, progressive, preparatory, supplemental, simultaneous, reversed, or other variations, unless the context dictates otherwise. Furthermore, terms such as past tense adjectives, such as "responsive to" and "related to," are generally not intended to exclude such variations, unless the context dictates otherwise.

[0068] It should be noted that references to "one embodiment," "an embodiment," "exemplary," "one example," etc. mean that a particular feature, structure, or characteristic described in connection with that embodiment is included in at least one embodiment. Thus, the appearances of the phrases "in one embodiment," "in an embodiment," "in an example," and "in one example" in various places throughout this specification do not necessarily all refer to the same embodiment. Furthermore, particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0069] Any patent applications, patents, non-patent publications, or other disclosure materials referred to herein and / or set forth in an Application Data Sheet are incorporated herein by reference to the extent that the incorporated material does not contradict this specification. Therefore, to the extent necessary, the disclosures expressly set forth herein supersede any conflicting material incorporated herein by reference. Any material, or portion thereof, purportedly incorporated herein by reference that contradicts any existing definitions, statements, or other disclosure material set forth herein is incorporated only to the extent that no conflict arises between the incorporated material and the existing disclosure material.

[0070] "Comprise" (and any forms of comprise, such as "comprises" and "comprising"), "have" (and any forms of have, such as "has" and "having"), "include" (and any forms of include, such as "includes" and "including"), and "contain" (and any forms of contain, such as "contains" and "containing") are open-ended linking verbs. Consequently, a system that "comprises," "has," "includes," or "contains" one or more elements possesses those one or more elements, but is not limited to possessing only those one or more elements. Similarly, an element of a system, device, or apparatus that "comprises," "has," "includes," or "contains" one or more features possesses those one or more features, but is not limited to possessing only those one or more features.

[0071] As used in this disclosure, the terms "substantially," "about," or "generally," unless otherwise specified, refer to an acceptable error for a particular value as determined by one of ordinary skill in the art, which depends in part on how the value is measured or determined. In certain embodiments, the terms "substantially," "about," or "generally" mean within 1, 2, 3, or 4 standard deviations. In certain embodiments, the terms "substantially," "about," or "generally" mean within 50%, 20%, 15%, 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, 0.5%, or 0.05% of a given value or range.

[0072] In summary, numerous advantages have been described that accrue from employing the concepts described herein. The foregoing description of one or more embodiments has been presented for purposes of illustration and description. It is not intended to be exhaustive or limiting to the precise embodiments disclosed. Modifications or variations are possible in light of the above teachings. The one or more embodiments have been selected and described in order to explain the principles and practical applications, so that one skilled in the art can utilize various embodiments with various modifications suited to the particular use contemplated. The claims filed herein are intended to define the overall scope.

Claims

1. 1. An in-situ wick rolling and forming assembly configured to roll and form a heat pipe wick from a wick mesh, comprising: a first molded shell; a grooved mandrel; an expandable member; the first molding shell is configured to mold the wick in situ after rolling the wick mesh; The first molded shell comprises: A first recess; a first dividing surface; a first central axis of the first recess is located below the first dividing surface, the grooved mandrel is removably positionable within the first recess; The grooved mandrel A first end; A second end; an elongate body between the first end and the second end and defining a longitudinal axis; a groove extending along the longitudinal axis; the groove is configured to receive a leading edge of the wick mesh; the expandable member is fluidly expandable to an expanded configuration; the expandable member is removably positionable inside the grooved mandrel; the expandable member is configured to contact the leading edge of the wick mesh in the expanded configuration such that the leading edge of the wick mesh is gripped between the grooved mandrel and the expandable member; the grooved mandrel is rotatable about the longitudinal axis relative to the first recess to wrap the wick mesh around an outer surface of the grooved mandrel; In-situ wick rolling forming assembly.

2. a second mold shell positionable relative to the first mold shell after rolling the wick mesh to form the wick in situ; The second molded shell comprises: A second recess; a second dividing surface; The in situ wick rolling mold assembly of claim 1 , wherein a second central axis of the second recess is located above the second parting surface.

3. the first recess has a first arc length; the second recess has a second arc length; The in situ wick rolling form assembly of claim 2 , wherein the first arc length is greater than the second arc length.

4. The in situ wick rolling mold assembly of claim 2 comprising a hydroforming die assembly including the first mold shell and the second mold shell.

5. 3. The in situ wick rolling mold assembly of claim 2, wherein the first mold shell and the second mold shell cooperate to define the outer diameter of the wick when the first mold shell and the second mold shell are combined to mold the wick.

6. a tensioner spaced apart from the first molded shell; 2. The in situ wick rolling mold assembly of claim 1, wherein the wick mesh can pass through the grooved mandrel through the tensioner while the grooved mandrel is within the first recess of the first mold shell.

7. The tensioner is With Laura, a bridge; the bridge is configured to be raised and lowered to insert the wick mesh between the roller and the bridge; 7. The in situ wick rolling mold assembly of claim 6.

8. The in situ wick rolling form assembly of claim 7 , wherein the bridge comprises a tension member configured to maintain a constant force on the roller.

9. The in situ wick rolling form assembly of claim 8 , wherein the tension member is spring biased toward the roller.

10. 7. The in situ wick rolling form assembly of claim 6, wherein the tensioner comprises a T-slot extruded aluminum support structure having a bridge.

11. the hydroforming die assembly is configured to shape the wick by permanently deforming the rolled wick mesh into a cylindrical structure; 5. The in situ wick rolling form assembly of claim 4, wherein the cylindrical structure has an outer diameter that matches an inner diameter of the hydroforming die assembly defined by the first and second forming shells while the first and second forming shells are in a combined configuration after rolling.

12. the hydroforming die assembly includes an expandable tube positionable inside the rolled wick mesh; 5. The in situ wick rolling mold assembly of claim 4, wherein the expandable tube is configured to mold the wick by permanently deforming the rolled wick mesh against an inner surface of the hydroforming die assembly defined by the first and second forming shells while the first and second forming shells are in a combined configuration after rolling.

13. The in situ wick rolling mold assembly of claim 4 , wherein the expandable member is an expandable bladder.

14. the first parting surface is angled upwardly away from the first recess; The in situ wick rolling mold assembly of claim 2 , wherein the second parting surface is angled downwardly away from the second recess.

15. 1. A method for forming a heat pipe wick in situ by rolling it from a wick mesh, comprising: threading the wick mesh through a tensioner toward a first forming shell of an in-situ wick rolling forming assembly; placing a grooved mandrel of the in-situ wick rolling form assembly into a first recess of the first form shell; clamping a leading edge of the wick mesh between the grooved mandrel and an expandable member disposed inside the grooved mandrel; rotating the grooved mandrel a plurality of times relative to the first forming shell about a longitudinal axis defined through the grooved mandrel to form the rolled wick mesh; contracting the expandable member to release the leading edge of the wick mesh; removing the grooved mandrel and the expandable member from the first forming shell; placing an expandable tube in situ inside the rolled wick mesh; securing a second mold shell relative to the first mold shell; expanding the expandable tube to permanently deform the rolled wick mesh against the interior surfaces of the first and second forming shells; A method for providing

16. 16. The method of rolling and forming a wick in situ as described in claim 15, wherein removing the grooved mandrel and the expandable member from the first forming shell occurs while the rolled wick mesh remains seated in the first forming shell.

17. 16. The method of claim 15, wherein removing the grooved mandrel and expandable member from the first forming shell occurs without disturbing the rolled wick mesh.

18. the first recess has a first arc length; the second mold shell includes a second recess having a second arcuate length; 16. The method of claim 15, wherein the first arc length is greater than the second arc length.

19. 16. The method for in-situ rolling and molding a wick as described in claim 15, wherein the first molding shell and the second molding shell cooperate to define the outer diameter of the wick when combined to form the wick.

20. the first molded shell further comprises a first parting surface; the second mold shell includes a second molding surface and a second recess; the first parting surface is angled upwardly away from the first recess; the second parting surface is angled downwardly away from the second recess; A method for in-situ rolling and forming the wick of claim 15.

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