US20160318101A1

US20160318101A1 - Integrated heat-exchanging mold systems

Info

Publication number: US20160318101A1
Application number: US14/782,862
Authority: US
Inventors: Grant O. Cook, III
Original assignee: Halliburton Energy Services Inc
Current assignee: Halliburton Energy Services Inc
Priority date: 2014-12-02
Filing date: 2014-12-02
Publication date: 2016-11-03
Also published as: WO2016089373A1

Abstract

An example integrated heat-exchanging mold system for fabricating an infiltrated downhole tool includes a mold assembly that defines an infiltration chamber to receive and contain matrix reinforcement materials and a binder material used to form the infiltrated downhole tool. A heat-exchanging enclosure is disposed about at least a portion of an exterior of the mold assembly, and the heat-exchanging enclosure includes one or more component parts that include at least one sidewall extending along a height of the mold assembly. One or more thermal conduits are positioned within the one or more component parts, including the at least one sidewall, and thereby placed in thermal communication with the infiltration chamber.

Description

BACKGROUND

A variety of downhole tools are used in the exploration and production of hydrocarbons. Examples of such downhole tools include cutting tools, such as drill bits, reamers, stabilizers, and coring bits; drilling tools, such as rotary steerable devices and mud motors; and other downhole tools, such as window mills, packers, tool joints, and other wear-prone tools. Rotary drill bits are often used to drill wellbores. One type of rotary drill bit is a fixed-cutter drill bit that has a bit body comprising matrix and reinforcement materials, i.e., a “matrix drill bit” as referred to herein. Matrix drill bits usually include cutting elements or inserts positioned at selected locations on the exterior of the matrix bit body. Fluid flow passageways are formed within the matrix bit body to allow communication of drilling fluids from associated surface drilling equipment through a drill string or drill pipe attached to the matrix bit body.
Matrix drill bits may be manufactured by placing powder material into a mold and infiltrating the powder material with a binder material, such as a metallic alloy. The various features of the resulting matrix drill bit, such as blades, cutter pockets, and/or fluid-flow passageways, may be provided by shaping the mold cavity and/or by positioning temporary displacement materials within interior portions of the mold cavity. A preformed bit blank (or mandrel) may be placed within the mold cavity to provide reinforcement for the matrix bit body and to allow attachment of the resulting matrix drill bit with a drill string. A quantity of matrix reinforcement material (typically in powder form) may then be placed within the mold cavity with a quantity of the binder material.
The mold is then placed within a furnace and the temperature of the mold is increased to a desired temperature to allow the binder (e.g., metallic alloy) to liquefy and infiltrate the matrix reinforcement material. The furnace may maintain this desired temperature to the point that the infiltration process is deemed complete, such as when a specific location in the bit reaches a certain temperature. Once the designated process time or temperature has been reached, the mold containing the infiltrated matrix bit is removed from the furnace. As the mold is removed from the furnace, the mold begins to rapidly lose heat to its surrounding environment via heat transfer, such as radiation and/or convection in all directions.
This heat loss continues to a large extent until the mold is moved and placed on a cooling plate and an insulation enclosure or “hot hat” is lowered around the mold. The insulation enclosure drastically reduces the rate of heat loss from the top and sides of the mold while heat is drawn from the bottom of the mold through the cooling plate. This controlled cooling of the mold and the infiltrated matrix bit contained therein can facilitate axial solidification dominating radial solidification, which is loosely termed directional solidification.
As the molten material of the infiltrated matrix bit cools, there is a tendency for shrinkage that could result in voids forming within the bit body unless the molten material is able to continuously backfill such voids. In some cases, for instance, one or more intermediate regions within the bit body may solidify prior to adjacent regions and thereby stop the flow of molten material to locations where shrinkage porosity is developing. In other cases, shrinkage porosity may result in poor metallurgical bonding at the interface between the bit blank and the molten materials, which can result in the formation of cracks within the bit body that can be difficult or impossible to inspect. When such bonding defects are present and/or detected, the drill bit is often scrapped during or following manufacturing assuming they cannot be remedied. Every effort is made to detect these defects and reject any defective drill bit components during manufacturing to help ensure that the drill bits used in a job at a well site will not prematurely fail and to minimize any risk of possible damage to the well.

BRIEF DESCRIPTION OF THE DRAWINGS

The following figures are included to illustrate certain aspects of the present disclosure, and should not be viewed as exclusive embodiments. The subject matter disclosed is capable of considerable modifications, alterations, combinations, and equivalents in form and function, without departing from the scope of this disclosure.

FIG. 1 is a perspective view of an exemplary fixed-cutter drill bit that may be fabricated in accordance with the principles of the present disclosure.

FIG. 2 is a cross-sectional view of the drill bit of FIG. 1.

FIG. 3 is a cross-sectional side view of an exemplary mold assembly for use in forming the drill bit of FIG. 1.

FIGS. 4A-4C are progressive schematic diagrams of an exemplary method of fabricating a drill bit.

FIGS. 5A-5C are partial cross-sectional side views of various exemplary integrated heat-exchanging mold systems.

FIG. 6 is a partial cross-sectional side view of another exemplary integrated heat-exchanging mold system.

FIGS. 7A-7F are cross-sectional views of various exemplary heat-exchanging modules.

FIGS. 8A and 8B are cross-sectional views of various additional exemplary heat-exchanging modules.

DETAILED DESCRIPTION

The present disclosure relates to tool manufacturing and, more particularly, to integrated heat-exchanging mold systems that can selectively heat and/or cool infiltrated downhole tools during fabrication.
The embodiments described herein provide integrated heat-exchanging mold systems used for fabricating an infiltrated downhole tool. The integrated heat-exchanging mold systems disclosed herein improve melting and solidification by introducing an alternate design to standard heating and cooling components commonly used during the infiltration and quenching processes of infiltrated downhole tools. As a result, a more controlled production process is achieved that provides desired thermal profiles for the infiltrated downhole tools.
As will be appreciated, controlled cooling and, therefore, solidification of the infiltrated downhole tool, may prove advantageous in preventing or otherwise mitigating the occurrence of some defects that commonly occur in infiltrated downhole tools, such as blank bond-line and nozzle cracking. The integrated heat-exchanging mold systems disclosed herein may also lower operating costs and/or heating/cooling cycle times. Moreover, this may improve quality and reduce the rejection rate of drill bit components due to defects during manufacturing.
FIG. 1 illustrates a perspective view of an example fixed-cutter drill bit 100 that may be fabricated in accordance with the principles of the present disclosure. It should be noted that, while FIG. 1 depicts a fixed-cutter drill bit 100, the principles of the present disclosure are equally applicable to any type of downhole tool that may be formed or otherwise manufactured through an infiltration process. For example, suitable infiltrated downhole tools that may be manufactured in accordance with the present disclosure include, but are not limited to, oilfield drill bits or cutting tools (e.g., fixed-angle drill bits, roller-cone drill bits, coring drill bits, bi-center drill bits, impregnated drill bits, reamers, stabilizers, hole openers, cutters, cutting elements), non-retrievable drilling components, aluminum drill bit bodies associated with casing drilling of wellbores, drill-string stabilizers, cones for roller-cone drill bits, models for forging dies used to fabricate support arms for roller-cone drill bits, arms for fixed reamers, arms for expandable reamers, internal components associated with expandable reamers, sleeves attached to an uphole end of a rotary drill bit, rotary steering tools, logging-while-drilling tools, measurement-while-drilling tools, side-wall coring tools, fishing spears, washover tools, rotors, stators and/or housings for downhole drilling motors, blades and housings for downhole turbines, and other downhole tools having complex configurations and/or asymmetric geometries associated with forming a wellbore.
As illustrated in FIG. 1, the fixed-cutter drill bit 100 (hereafter “the drill bit 100”) may include or otherwise define a plurality of cutter blades 102 arranged along the circumference of a bit head 104. The bit head 104 is connected to a shank 106 to form a bit body 108. The shank 106 may be connected to the bit head 104 by welding, such as using laser arc welding that results in the formation of a weld 110 around a weld groove 112. The shank 106 may further include or otherwise be connected to a threaded pin 114, such as an American Petroleum Institute (API) drill pipe thread. 122
In the depicted example, the drill bit 100 includes five cutter blades 102, in which multiple recesses or pockets 116 are formed. Cutting elements 118 may be fixedly installed within each recess 116. This can be done, for example, by brazing each cutting element 118 into a corresponding recess 116. As the drill bit 100 is rotated in use, the cutting elements 118 engage the rock and underlying earthen materials, to dig, scrape or grind away the material of the formation being penetrated.
During drilling operations, drilling fluid or “mud” can be pumped downhole through a drill string (not shown) coupled to the drill bit 100 at the threaded pin 114. The drilling fluid circulates through and out of the drill bit 100 at one or more nozzles 120 positioned in nozzle openings 122 defined in the bit head 104. Junk slots 124 are formed between each adjacent pair of cutter blades 102. Cuttings, downhole debris, formation fluids, drilling fluid, etc., may pass through the junk slots 124 and circulate back to the well surface within an annulus formed between exterior portions of the drill string and the inner wall of the wellbore being drilled.
FIG. 2 is a cross-sectional side view of the drill bit 100 of FIG. 1. Similar numerals from FIG. 1 that are used in FIG. 2 refer to similar components that are not described again. As illustrated, the shank 106 may be securely attached to a metal blank (or mandrel) 202 at the weld 110 and the metal blank 202 extends into the bit body 108. The shank 106 and the metal blank 202 are generally cylindrical structures that define corresponding fluid cavities 204 a and 204 b, respectively, in fluid communication with each other. The fluid cavity 204 b of the metal blank 202 may further extend longitudinally into the bit body 108. At least one flow passageway (shown as two flow passageways 206 a and 206 b) may extend from the fluid cavity 204 b to exterior portions of the bit body 108. The nozzle openings 122 may be defined at the ends of the flow passageways 206 a and 206 b at the exterior portions of the bit body 108. The pockets 116 are formed in the bit body 108 and are shaped or otherwise configured to receive the cutting elements 118 (FIG. 1).
FIG. 3 is a cross-sectional side view of a mold assembly 300 that may be used to form the drill bit 100 of FIGS. 1 and 2. While the mold assembly 300 is shown and discussed as being used to help fabricate the drill bit 100, those skilled in the art will readily appreciate that mold assembly 300 and its several variations described herein may be used to help fabricate any of the infiltrated downhole tools mentioned above, without departing from the scope of the disclosure. As illustrated, the mold assembly 300 may include several components such as a mold 302, a gauge ring 304, and a funnel 306. In some embodiments, the funnel 306 may be operatively coupled to the mold 302 via the gauge ring 304, such as by corresponding threaded engagements, as illustrated. In other embodiments, the gauge ring 304 may be omitted from the mold assembly 300 and the funnel 306 may be instead be operatively coupled directly to the mold 302, such as via a corresponding threaded engagement, without departing from the scope of the disclosure.
In some embodiments, as illustrated, the mold assembly 300 may further include a binder bowl 308 and a cap 310 placed above the funnel 306. The mold 302, the gauge ring 304, the funnel 306, the binder bowl 308, and the cap 310 may each be made of or otherwise comprise graphite or alumina (Al₂O₃), for example, or other suitable materials. An infiltration chamber 312 may be defined or otherwise provided within the mold assembly 300. Various techniques may be used to manufacture the mold assembly 300 and its components including, but not limited to, machining graphite blanks to produce the various components and thereby define the infiltration chamber 312 to exhibit a negative or reverse profile of desired exterior features of the drill bit 100 (FIGS. 1 and 2).
Materials, such as consolidated sand or graphite, may be positioned within the mold assembly 300 at desired locations to form various features of the drill bit 100 (FIGS. 1 and 2). For example, consolidated sand legs 314 a and 314 b may be positioned to correspond with desired locations and configurations of the flow passageways 206 a,b (FIG. 2) and their respective nozzle openings 122 (FIGS. 1 and 2). Moreover, a cylindrically-shaped consolidated sand core 316 may be placed on the legs 314 a,b. The number of legs 314 a,b extending from the sand core 316 will depend upon the desired number of flow passageways and corresponding nozzle openings 122 in the drill bit 100.
After the desired materials, including the sand core 316 and the legs 314 a,b, have been installed within the mold assembly 300, matrix reinforcement materials 318 may then be placed within or otherwise introduced into the mold assembly 300. For some applications, two or more different types of matrix reinforcement materials 318 may be deposited in the mold assembly 300. Suitable matrix reinforcement materials 318 include, but are not limited to, tungsten carbide, monotungsten carbide (WC), ditungsten carbide (W₂C), macrocrystalline tungsten carbide, other metal carbides, metal borides, metal oxides, metal nitrides, natural and synthetic diamond, and polycrystalline diamond (PCD). Examples of other metal carbides may include, but are not limited to, titanium carbide and tantalum carbide, and various mixtures of such materials may also be used.
The metal blank 202 may be supported at least partially by the matrix reinforcement materials 318 within the infiltration chamber 312. More particularly, after a sufficient volume of the matrix reinforcement materials 318 has been added to the mold assembly 300, the metal blank 202 may then be placed within mold assembly 300 and concentrically-arranged about the sand core 316. The metal blank 202 may include an inside diameter 320 that is greater than an outside diameter 322 of the sand core 316, and various fixtures (not expressly shown) may be used to position the metal blank 202 within the mold assembly 300 at a desired location. The matrix reinforcement materials 318 may then be filled to a desired level within the infiltration chamber 312.
Binder material 324 may then be placed on top of the matrix reinforcement materials 318, the metal blank 202, and the sand core 316. Various types of binder materials 324 may be used and include, but are not limited to, metallic alloys of copper (Cu), nickel (Ni), manganese (Mn), lead (Pb), tin (Sn), cobalt (Co) and silver (Ag). Phosphorous (P) may sometimes also be added in small quantities to reduce the melting temperature range of infiltration materials positioned in the mold assembly 300. Various mixtures of such metallic alloys may also be used as the binder material 324. In some embodiments, the binder material 324 may be covered with a flux layer (not expressly shown). The amount of binder material 324 and optional flux material added to the infiltration chamber 312 should be at least enough to infiltrate the matrix reinforcement materials 318 during the infiltration process. In some instances, some or all of the binder material 324 may be placed in the binder bowl 308, which may be used to distribute the binder material 324 into the infiltration chamber 312 via various conduits 326 that extend therethrough. The cap 310 (if used) may then be placed over the mold assembly 300, thereby readying the mold assembly 300 for heating.
Referring now to FIGS. 4A-4C, with continued reference to FIG. 3, illustrated are schematic diagrams that sequentially illustrate an example method of heating and cooling the mold assembly 300 of FIG. 3. In FIG. 4A, the mold assembly 300 is depicted as being positioned within a furnace 402. The temperature of the mold assembly 300 and its contents are elevated within the furnace 402 until the binder material 324 liquefies and is able to infiltrate the matrix reinforcement materials 318. Once a specific location in the mold assembly 300 reaches a certain temperature in the furnace 402, or the mold assembly 300 is otherwise maintained at a particular temperature for a predetermined amount of time, the mold assembly 300 is then removed from the furnace 402 and immediately begins to lose heat by radiating thermal energy to its surroundings while heat is also convected away by cooler air outside the furnace 402. In some cases, as depicted in FIG. 4B, the mold assembly 300 may be transported to and set down upon a thermal heat sink 404.
The radiative and convective heat losses from the mold assembly 300 to the environment continue until an insulation enclosure 406 is lowered around the mold assembly 300. The insulation enclosure 406 may be a rigid shell or structure used to insulate the mold assembly 300 and thereby slow the cooling process. In some cases, the insulation enclosure 406 may include a hook 408 attached to a top surface thereof. The hook 408 may provide an attachment location, such as for a lifting member, whereby the insulation enclosure 406 may be grasped and/or otherwise attached to for transport. For instance, a chain or wire 410 may be coupled to the hook 408 to lift and move the insulation enclosure 406, as illustrated. In other cases, a mandrel or other type of manipulator (not shown) may grasp onto the hook 408 to move the insulation enclosure 406 to a desired location.
The insulation enclosure 406 may include an outer frame 412, an inner frame 414, and insulation material 416 arranged between the outer and inner frames 412, 414. In some embodiments, both the outer frame 412 and the inner frame 414 may be made of rolled steel and shaped (i.e., bent, welded, etc.) into the general shape, design, and/or configuration of the insulation enclosure 406. In other embodiments, the inner frame 414 may be a metal wire mesh that holds the insulation material 416 between the outer frame 412 and the inner frame 414. The insulation material 416 may be selected from a variety of insulative materials, such as those discussed below. In at least one embodiment, the insulation material 416 may be a ceramic fiber blanket, such as INSWOOL® or the like.
As depicted in FIG. 4C, the insulation enclosure 406 may enclose the mold assembly 300 such that thermal energy radiating from the mold assembly 300 is dramatically reduced from the top and sides of the mold assembly 300 and is instead directed substantially downward and otherwise toward/into the thermal heat sink 404 or back towards the mold assembly 300. In the illustrated embodiment, the thermal heat sink 404 is a cooling plate designed to circulate a fluid (e.g., water) at a reduced temperature relative to the mold assembly 300 (i.e., at or near ambient) to draw thermal energy from the mold assembly 300 and into the circulating fluid, and thereby reduce the temperature of the mold assembly 300. In other embodiments, however, the thermal heat sink 404 may be any type of cooling device or heat exchanger configured to encourage heat transfer from the bottom 418 of the mold assembly 300 to the thermal heat sink 404. In yet other embodiments, the thermal heat sink 404 may be any stable or rigid surface that may support the mold assembly 300, and preferably having a high thermal capacity, such as a concrete slab or flooring.
Once the insulation enclosure 406 is positioned over the mold assembly 300 and the thermal heat sink 404 is operational, the majority of the thermal energy is transferred away from the mold assembly 300 through the bottom 418 of the mold assembly 300 and into the thermal heat sink 404. This controlled cooling of the mold assembly 300 and its contents allows an operator to regulate or control the thermal profile of the mold assembly 300 to a certain extent and may result in directional solidification of the molten contents within the mold assembly 300, where axial solidification of the molten contents dominates radial solidification. Within the mold assembly 300, the face of the drill bit (i.e., the end of the drill bit that includes the cutters) may be positioned at the bottom 418 of the mold assembly 300 and otherwise adjacent the thermal heat sink 404 while the shank 106 (FIG. 1) may be positioned adjacent the top of the mold assembly 300. As a result, the drill bit 100 (FIGS. 1 and 2) may be cooled axially upward, from the cutters 118 (FIG. 1) toward the shank 106 (FIG. 1).
Such directional solidification (from the bottom up) may prove advantageous in reducing the occurrence of voids due to shrinkage porosity, cracks at the interface between the metal blank 202 (FIGS. 2 and 3) and the molten materials within the infiltration chamber 312 (FIG. 3), and nozzle cracks. However, the insulating capability of the insulation enclosure 406 may require augmentation to produce a sufficient amount of directional cooling. According to embodiments of the present disclosure, as an alternative or in addition to using the insulation enclosure 406, an integrated heat-exchanging mold system may be used to help influence the overall thermal profile of the infiltrated downhole tool (e.g., the drill bit 100 of FIGS. 1 and 2) and facilitate a sufficient amount of directional cooling. The integrated heat-exchanging mold systems described herein allow an operator to selectively and actively heat and/or cool various portions of a given mold assembly and thereby improve directional solidification of an infiltrated downhole tool.
Referring to FIGS. 5A-5C, illustrated are partial cross-sectional side views of various exemplary integrated heat-exchanging mold systems, according to one or more embodiments. More particularly, FIG. 5A depicts a first integrated heat-exchanging mold system (hereafter “system”) 500 a, FIG. 5B depicts a second system 500 b, and FIG. 5C depicts a third system 500 c. The systems 500 a-c may be similar in some respect and may each include a mold assembly 502, which may be similar to the mold assembly 300 of FIG. 3. As illustrated, for instance, the mold assembly 502 may include the mold 302, the funnel 306, the binder bowl 308, and the cap 310. In some embodiments, while not shown in FIGS. 5A-5C, the gauge ring 304 (FIG. 3) may also be included in the mold assembly 502. The mold assembly 502 may further include the metal blank 202, the sand core 316, and one or more consolidated sand legs 314 b (one shown), as generally discussed above.
The systems 500 a-c may further include a heat-exchanging enclosure 504 that may be selectively operated to actively manipulate the thermal profiles of the contents 506 within the infiltration chamber 312. The heat-exchanging enclosure 504 (hereafter “the enclosure 504”) may include a sidewall 508 configured to encompass and otherwise extend about the outer periphery of the mold assembly 502. The enclosure 504 may exhibit any suitable horizontal cross-sectional shape that accommodates the general shape of the mold assembly 502 including, but not limited to, circular, ovular, polygonal, polygonal with rounded corners, or any hybrid thereof. In some embodiments, the sidewall 508 may exhibit different horizontal cross-sectional shapes and/or sizes along its height and otherwise at different vertical or longitudinal locations.
In some embodiments, the sidewall 508 may be disposed about the mold assembly 502 such that the enclosure 504 is in direct contact with the sides of the mold assembly 502, such as in contact with one or more of the mold 302, the funnel 306, and the binder bowl 308 (if used). In other embodiments, a gap 509 (FIG. 5A) may separate the sidewall 508 from adjacent portions of the mold assembly 502. In some embodiments, the gap 509 may be fairly small or miniscule, such as about a few millimeters or less. In other embodiments, however, the gap 509 may be greater than a few millimeters, as discussed below. The gap 509 may prove advantageous not only in allowing the enclosure 504 to fit around the mold assembly 502, but also in accommodating any thermal expansion mismatches between different materials of the sidewall 508 and adjacent portions of the mold assembly 502. In at least one embodiment, the gap 509 may be filled with a suitable refractory and conductive material to promote conductive heat transfer across that interface.
Furthermore, in some embodiments, the gap 509 may be large enough to accommodate a sleeve 511 (FIG. 5A) that may be positioned in the gap 509 between the mold assembly 502 and the sidewall 508. The sleeve 511 may prove useful in accommodating mold assemblies of varying sizes using a minimal number of sidewall 508 sizes. In this manner, the capital investment in such an enclosure could be minimized compared to the range of mold assembly 502 sizes, and, therefore, bit sizes that could be processed. As an example, a sidewall 508 of internal radius R could accommodate mold assemblies 502 of external radii 0.85R, 0.9R, or 0.95R using sleeves of internal radii 0.85R+i, 0.9R+i, and 0.95R+i and external radii R-o, R-o, and R-o, respectively, where i represents a suitable gap between the mold assembly 502 and the sleeve 511 and o represents a suitable gap between the sleeve 511 and sidewall 508. The sleeve 511 may be formed of any suitably refractory and conductive material, such as graphite or alumina. Alternatively, the gap 509 between mold assembly 502 and sidewall 508 can remain empty or be filled with a fluid or powder to promote conductive heat transfer versus convective and/or radiative heat transfer.
Furthermore, sleeve 511 may be constructed of a suitable conductive or insulative material and in a geometrical form to further control heat transfer to or from the mold assembly 502. Examples include two cylinders, one stacked on the other, with differing thermal properties; a short cylinder that only contacts the lower portion of mold assembly 502, for example, up to gauge ring 304; or a cylinder supported on stilts (not axisymmetric) that provides more contact along the upper portion of mold assembly 502. The sleeve 511 may exhibit any suitable horizontal cross-sectional shape that accommodates the general shape of the mold assembly 502 including, but not limited to, circular, ovular, polygonal, polygonal with rounded corners, or any hybrid thereof. In some embodiments, the sleeve 511 may exhibit different horizontal cross-sectional shapes and/or sizes along its height and otherwise at different vertical or longitudinal locations. In at least one embodiment, the gap 509 may be filled with both a suitable refractory and conductive material to promote conductive heat transfer across that interface and the sleeve 511, without departing from the scope of the disclosure.
As illustrated in FIGS. 5B and 5C, the enclosure 504 may further include one or more of a top plate 510 a and a bottom plate 510 b. The top plate 510 a may be positioned above the mold assembly 502, and the bottom plate 510 b may be positioned below the mold assembly 502. In some embodiments, the top plate 510 a may rest directly on the mold assembly 502, such as on the cap 310, the binder bowl 308, or the funnel 306 (depending on which components of the mold assembly 502 are used). In other embodiments, the top plate 510 a may engage and otherwise rest atop the sidewall(s) 508. The mold assembly 502 and, more particularly, the mold 302, may rest on the bottom plate 510 b.
The sidewall(s) 508, the top plate 510 a (if used), and the bottom plate 510 b (if used) are collectively referred to herein as the “component parts” of the enclosure 504. Each component part of the enclosure 504 may be made of a suitable material including, but not limited to, graphite, alumina (Al₂O₃), a metal, a ceramic, and any combination thereof.
A plurality of thermal conduits 512 may be positioned within one or more of the component parts of the enclosure 504. As used herein, the term “positioned within” can refer to physically embedding the thermal conduits 512 within one or more of the component parts of the enclosure 504, but may also refer to the thermal conduits 512 forming an integral part of one or more of the component parts, such as by defining conduits directly in the material of the given component parts (i.e., via machining and/or assembling processes). In yet other embodiments, as discussed below, the thermal conduits 512 may be positioned within a given component part of the enclosure 504 by being arranged within a fluid flow passage or cavity 610 (FIG. 6) defined within the given component part of the enclosure 504.
The thermal conduits 512 may be configured to circulate a fluid 514 through portions of the enclosure 504 and thereby place the fluid 514 in thermal communication with the contents 506 of the infiltration chamber 312. As used herein, the term “thermal communication” may mean that thermal energy can be exchanged between the fluid 514 and the infiltration chamber 312 (or its contents 506). In some embodiments, for instance, thermal energy may be imparted and/or transferred to the infiltration chamber 312 (or the contents 506 thereof) from the fluid 514. In other embodiments, however, the fluid 514 may be configured to extract thermal energy from the infiltration chamber 312 (or its contents 506). Accordingly, circulating the fluid 514 through the thermal conduits 512 may allow an operator to selectively manipulate the thermal profile of the contents 506 within the infiltration chamber 312.
In at least one embodiment, the contents 506 within the infiltration chamber 312 may comprise the individual or separated portions of the matrix reinforcement materials 318 (FIG. 3) and the binder material 324 (FIG. 3). In such embodiments, the fluid 514 may actively and/or selectively provide thermal energy to the matrix reinforcement materials 318 and the binder material 324 to help facilitate the infiltration process. In such embodiments, the furnace 402 of FIG. 4A may be omitted or otherwise supported through operation of the enclosure 504. In other embodiments, however, the contents 506 within the infiltration chamber 312 may be a molten mass following the infiltration process, and the fluid 514 may be configured to extract thermal energy from the molten mass and thereby help directional solidification as it cools.
The fluid 514 may be any fluidic substance that exhibits suitable properties, such as high thermal conductivity, high thermal diffusivity, high density, low viscosity (kinematic or dynamic), high specific heat, and high boiling point and low vapor pressure for liquids, to enable the fluid 514 to exchange thermal energy with the contents 506 within the infiltration chamber 312. Suitable fluids 514 that may be used include, but are not limited to, a gas (e.g., air, carbon dioxide, argon helium, oxygen, nitrogen), water, steam, an oil, a coolant (e.g., glycols), a molten metal, a molten metal alloy, a fluidized bed, or a molten salt. Suitable molten salts include alkali fluoride salts (e.g., LiF—KF, LiF—NaF—KF, LiF—RbF, LiF—NaF—RbF), BeF₂salts (e.g., LiF—BeF₂, NaF—BeF₂, LiF—NaF—BeF₂), ZrF₄salts (e.g., KF—ZrF₄, NaF—ZrF₄, NaF—KF—ZrF₄, LiF—ZrF₄, LiF—NaF—ZrF₄, RbF—ZrF₄), chloride-based salts (e.g., LiCl—KCl, LiCl—RbCl, KCl—MgCl₂, NaCl—MgCl₂, LiCl—KCl—MgCl₂, KCl—NaCl—MgCl₂), fluoroborate-based salts (e.g., NaF—NaBF₄, KF—KBF₄, RbF—RbBF₄), or nitrate-based salts (e.g., NaNO₃—KNO₃, Ca(NO₃)₂—NaNO₃—KNO₃, LiNO₃—NaNO₃—KNO₃), and any alloys thereof. Suitable molten metals or metal alloys for the fluid 514 may include Pb, Bi, Pb—Bi, K, Na, Na—K, Ga, In, Sn, Li, Zn, or any alloys thereof.
The thermal conduits 512 may each be fluidly coupled and otherwise connected to a heat exchanger 516 configured to thermally condition the fluid 514. As used herein, the term “thermally condition” refers to heating or cooling the fluid 514. Whether the heat exchanger 516 thermally conditions the fluid 514 by heating or cooling the fluid 514 will depend on the application. The heat exchanger 516 may include a pump 518 operable to circulate the fluid 514 through the thermal conduits 512 and back to the heat exchanger 516 for continuous thermal conditioning of the fluid 514. The heat exchanger 516 may comprise any type of heat exchanging apparatus that is capable of maintaining the fluid 514 at a predetermined or preselected temperature for circulation through the thermal conduits 512. Suitable heat exchangers 516 may comprise or otherwise include, but are not limited to, a heating element, a radiant heater, an electric heater, an infrared heater, an induction heater, one or more induction coils, a heating band, one or more heated coils, or any combination thereof. Suitable configurations for a heating element may include, but are not be limited to, coils, tubes, bundled tubes, concentric tubes, plates, corrugated plates, strips, shells, baffles, channels, micro-channels, finned coils, finned plates, finned strips, louvered fins, wavy fins, pin fins, and the like, or any combination thereof.
The thermal conduits 512 positioned within any of the component parts of the enclosure 504 may exhibit various cross-sectional shapes. While depicted in FIGS. 5A-5C as exhibiting a generally square cross-sectional shape, the conduits 512 may alternatively exhibit a circular cross-sectional shape or any other cross-sectional shape capable of facilitating the circulation of the fluid 514, without departing from the scope of the disclosure.
Moreover, the thermal conduits 512 positioned within any of the component parts of the enclosure 504 may exhibit various designs and/or configurations. In some embodiments, for instance, the thermal conduits 512 positioned in the top or the bottom plates 510 a,b may comprise a single thermal conduit 512 forming part of the same fluid circuit and may form a spiraling or coiled conduit or fluid passageway when viewed from a top perspective. Likewise, the thermal conduits 512 positioned in the sidewall 508 may comprise a single thermal conduit 512 that forms part of the same fluid circuit and may complete several helical revolutions about the mold assembly 502 from top to bottom. In such embodiments, the single thermal conduit 512 of the top or bottom plates 510 a,b or the sidewall 508 may be controlled via a single fluidic lead connected to the heat exchanger 516 and routed back to the thermal conduit 512 via the pump 518. In at least some embodiments, single thermal conduits 512 positioned within the sidewall 508 and one or both of the top and bottom plates 510 a,b may be in fluid communication with each other and a common heat exchanger 516 and pump 518.
In other embodiments, however, the thermal conduits 512 in one or more of the component parts of the enclosure 504 may comprise two or more sets of thermal conduits 512 associated with a corresponding two or more fluid circuits that are controlled independent of one another. In such embodiments, the systems 500 a-c may include two or more heat exchangers 516 and associated pumps 518 to accommodate circulation of the fluid 514 through the independent fluid circuits. In yet other embodiments, the thermal conduits 512 in one or more of the component parts of the enclosure 504 may comprise individual and discrete thermal conduits 512 that are each fluidly coupled to the heat exchanger 516 or a plurality of different heat exchangers 516 and associated pumps 518. In such embodiments, each thermal conduit 512 would require connection to a corresponding discrete fluid circuit to circulate the fluid 514 through each thermal conduit 512. By fluidly coupling selected thermal conduits 512 to different heat exchangers 516, an operator may be able to selectively and actively vary the thermal profile within the infiltration chamber 312 and thereby produce a desired heat gradient within the mold assembly 502. Alternatively, actuated baffle-like members may be incorporated in each thermal conduit 512 to restrict or expand flow within each conduit to thereby modulate imposed heat gradients using a minimum number of heat exchangers 516 and/or pumps 518.
As will be appreciated, being able to selectively and actively adjust and otherwise optimize the level of directional heat imparted by the fluid 514 may prove advantageous in being able to vary the thermal profile within the infiltration chamber 312. In at least one embodiment, certain thermal conduits 512 or sets of thermal conduits 512 may be designed to operate simultaneously with or independent of other thermal conduits 512. For instance, the thermal conduits 512 near the top of the sidewall 508 and the thermal conduits 512 in the top plate 510 a may be heated at a later point during an infiltration process, such as once the thermal conduits 512 in the bottom plate 510 b and the thermal conduits 512 near the bottom of the sidewall 508 have had sufficient time to heat the matrix reinforcement materials 318 (FIG. 3) to a suitably high temperature. To help promote directional heating, certain thermal conduits 512 at the middle of the sidewall 508 may be “turned off” (e.g., circulation is stopped) at this time or may circulate a cooling fluid 514 until, for example, the thermal conduits 512 near the top of the sidewall 508 and the thermal conduits 512 in the top plate 510 a are activated. As a result, a desired thermal gradient may be generated and optimized along an axial height A (FIG. 5A) of the mold assembly 502 to help facilitate directional heating of the mold assembly 502 and its contents, including the metal blank 202 and reinforcement materials 318, and melting of the binder material 324 (FIG. 3). Alternatively, this process may be reversed to promote directional cooling of the mold assembly 502 and its contents, including the molten contents 506 within the infiltration chamber 312, along the axial height A.
Moreover, it will be appreciated that the configuration (e.g., number, placement, spacing, size, etc.) of the thermal conduits 512 in the sidewall 508 (or any of the other component parts) may be optimized and/or selectively operated to further enhance the thermal gradient along the axial height A. Furthermore, certain thermal conduits 512 or sets of thermal conduits 512 may be designed with the ability to switch between a heating fluid 514 and a cooling fluid 514 to achieve a desired thermal profile throughout the heating and cooling cycles.
As illustrated, the systems 500 a-c may further include an outer insulation assembly 520 configured to encompass and otherwise extend about the enclosure 504. The outer insulation assembly 520 (hereafter “the insulation assembly 520”) may be similar in some respects to the insulation enclosure 406 of FIGS. 4B and 4C. The insulation assembly 520 may include a sidewall insulator 522 and, as depicted in FIGS. 5B and 5C, may optionally include one or more of a top insulator 524 a and a bottom insulator 524 b. The sidewall, top, and bottom insulators 522, 524 a,b may each be configured to insulate the mold assembly 502 and the enclosure 504. The sidewall, top, and bottom insulators 522, 524 a,b may each comprise a rigid frame or structure that includes insulation material 526 either supported by the rigid structure or otherwise arranged between inner and outer frames of the rigid structure. The rigid structure may be made of rolled steel and shaped (i.e., bent, welded, etc.) into the general shape, design, and/or configuration of the enclosure 504. In other embodiments, the rigid structure may comprise a metal wire mesh that holds the insulation material 526 in place.
The insulation material 526 may be selected from a variety of insulative materials including, but not limited to, ceramics (e.g., oxides, carbides, borides, nitrides, and silicides that may be crystalline, non-crystalline, or semi-crystalline), polymers, insulating metal composites, carbons, nanocomposites, foams, fluids (e.g., air), any composite thereof, or any combination thereof. The insulation material 526 may further include, but is not limited to, materials in the form of beads, particulates, flakes, fibers, wools, woven fabrics, bulked fabrics, sheets, bricks, stones, blocks, cast shapes, molded shapes, foams, sprayed insulation, and the like, any hybrid thereof, or any combination thereof. Accordingly, examples of suitable materials that may be used as the insulation material 526 may include, but are not limited to, alumina, ceramics, ceramic fibers, ceramic fabrics, ceramic wools, ceramic beads, ceramic blocks, moldable ceramics, woven ceramics, cast ceramics, fire bricks, carbon fibers, graphite blocks, shaped graphite blocks, polymer beads, polymer fibers, polymer fabrics, nanocomposites, fluids in a jacket, metal fabrics, metal foams, metal wools, metal castings, and the like, any composite thereof, or any combination thereof.
Referring specifically to FIG. 5C, the sidewall insulator 522 and the top insulator 524 a may be coupled and otherwise combined into a monolithic structure in one or more embodiments. In such embodiments, the sidewall and top insulators 522, 524 a may be raised by an operator in the direction B at a controlled rate or over two or more predefined intervals (i.e., longitudinal distances and/or time lapses). As will be appreciated, this may prove advantageous in gradually exposing portions of the mold assembly 502 and the enclosure 504 and thereby resulting in a given cooling rate of the mold assembly 502 as heat is progressively lost out of the sides of the mold assembly 502 and the enclosure 504. Moreover, in some embodiments, the bottom insulator 524 b may be configured to move laterally C with respect to the mold assembly 502, and thereby allow increased heat loss through the bottom of the mold assembly 502 when moved out from beneath. Similar to the sidewall and top insulators 522, 524 a, the bottom insulator 524 b may be moved laterally C by an operator at a controlled rate or over two or more predefined intervals (i.e., longitudinal distances and/or time lapses).
Referring again to each of FIGS. 5A-5C, a thermal barrier (not shown) may be applied to an inner or outer surface of the enclosure 504 and/or to an inner surface of the insulation assembly 520. The thermal barrier may provide resistance to radiation or conduction heat transfer between the mold assembly 502 and the exterior of the systems 500 a-c, depending on the separation distance between the enclosure 504 and the insulation assembly 520. Suitable materials that may be used as the thermal barrier include, but are not limited to, a ceramic-fiber blanket, aluminum oxide, aluminum nitride, silicon carbide, silicon nitride, quartz, titanium carbide, titanium nitride, borides, carbides, nitrides, and oxides. The thermal barrier may further include, but is not limited to, materials in the form of woven fabrics, bulked fabrics, sheets, bricks, stones, blocks, cast shapes, molded shapes, foams, sprayed insulation, and the like, any hybrid thereof, or any combination thereof. The thermal barrier may be applied via a variety of processes or techniques including, but not limited to, electron beam physical vapor deposition, air plasma spray, high velocity oxygen fuel, electrostatic spray assisted vapor deposition, and direct vapor deposition. Conversely, a highly conductive material, such as a diamond coating, a metallic sheet, or the like, may be applied to an inner surface of the enclosure 504, an outer surface of the mold assembly 502, and/or in the gap 509 (FIG. 5A) defined between the mold assembly 502 and the enclosure 504. In at least one embodiment, a gas may be used to fill the gap 509 or a gap 612 (FIG. 6) between the enclosure 504 and the insulation assembly 520.
In some embodiments, a reflective coating (not shown) may be applied to an inner and/or outer surface of the enclosure 504 or an inner surface of the insulation assembly 520. The reflective coating may be adhered to and/or sprayed onto a surface of the enclosure 504 or insulation assembly 520 to reflect an amount of thermal energy being transferred from the molten contents within the mold assembly 502 back toward the molten contents. Suitable materials for the reflective coating include a metal coating selected from the group consisting of iron, chromium, copper, carbon steel, maraging steel, stainless steel, microalloyed steel, low alloy steel, molybdenum, nickel, platinum, silver, gold, tantalum, tungsten, titanium, aluminum, cobalt, rhenium, osmium, palladium, iridium, rhodium, ruthenium, manganese, niobium, vanadium, zirconium, hafnium, any derivative thereof, or any alloy based on these metals. A metal reflective coating may be applied via a suitable method, such as plating, spray deposition, chemical vapor deposition, plasma vapor deposition, etc. Alternatively, the coating material may be formed on a removable or thin substrate or as a thin member coupled to a given surface of the enclosure 504 or insulation assembly 520. Another suitable material for the reflective coating may be a paint (e.g., white for high reflectivity, black for high absorptivity). In other embodiments, or in addition thereto, one or more of the surfaces of the enclosure 504 or insulation assembly 520 may be polished so as to increase its emissivity.
In some embodiments, the sidewall(s) 508 may be segmented and otherwise divided into multiple segments or rings that contain subsets of the total number of thermal conduits 512 used in the sidewall(s) 508. For example, the individual segments of the sidewall(s) 508 may contain 1 to n−1 thermal conduits 512, where n is the total number of thermal conduits 512 in the sidewall(s) 508. This may allow for an interchangeable design so that a range of drill bit (and mold assembly) sizes can be accommodated with minimal material and setup costs. In FIGS. 5B and 5C, as an example, there are 10 thermal conduits 512 positioned within the sidewall(s) 508. In some embodiments, the sidewall(s) 508 may be segmented and otherwise fabricated into multiple sidewall rings, where one sidewall ring contains six thermal conduits 512, a second sidewall ring contains two thermal conduits 512, and a third sidewall ring also contains two thermal conduits 512. Alternatively, the first sidewall ring may contain seven thermal conduits 512, the second sidewall ring may contain two thermal conduits 512, and the third sidewall ring may contain one thermal conduit 512. In another embodiment, the first sidewall ring may contain five thermal conduits 512, the second sidewall ring may contain three thermal conduits 512, and the third sidewall ring may contain two thermal conduits 512. As will be appreciated, several other configurable designs and segmentations may be employed, without departing from the scope of the disclosure. With such a configurable design, multiple sidewall 508 heights and, therefore, mold assembly 502 heights A (FIG. 5A), may be possible.
Referring now to FIG. 6, with continued reference to FIGS. 5A-5C, illustrated is a partial cross-sectional side view of another exemplary integrated heat-exchanging mold system 600, according to one or more embodiments. The integrated heat-exchanging mold system 600 (hereafter “the system 600”) may be similar in some respects to the systems 500 a-c of FIGS. 5A-5C, respectively, and therefore may be best understood with reference thereto, where like numerals represent like components not described again in detail. As illustrated, the system 600 may include the mold assembly 502, which may include the mold 302, the funnel 306, the binder bowl 308, the cap 310, the metal blank 202, the sand core 316, one or more consolidated sand legs 314 b (one shown), and optionally the gauge ring 304 (FIG. 3). The system 600 may further include a heat-exchanging enclosure 602 and the insulation assembly 520 arranged about the heat-exchanging enclosure 602.
The heat-exchanging enclosure 602 (hereafter “the enclosure 602”) may be similar in some respects to the enclosure 504 of FIGS. 5A-5C and therefore may be selectively operated to actively manipulate the thermal profile of the contents 506 within the infiltration chamber 312. For instance, the enclosure 602 may include a sidewall 604, and may optionally include one or both of a top plate 606 a and a bottom plate 606 b. Similar to the enclosure 504, the enclosure 602 may exhibit any suitable horizontal cross-sectional shape that accommodates the general shape of the mold assembly 502 including, but not limited to, circular, ovular, polygonal, polygonal with rounded corners, or any hybrid thereof. In some embodiments, the sidewall 604 may exhibit different horizontal cross-sectional shapes and/or sizes along its height and otherwise at different vertical or longitudinal locations.
Unlike the enclosure 504 of FIGS. 5A-5C, however, the sidewall 604 and the top and bottom plates 606 a,b may each comprise a plurality of heat-exchanging modules 608. The heat-exchanging modules 608 (hereafter “the modules 608”) may form annular rings configured to encompass and otherwise extend about the outer periphery and general exterior of the mold assembly 502.
The sidewall 604 may include multiple modules 608 stacked atop one another along the sides of the mold assembly 502. The top and bottom plates 606 a,b may comprise a plurality of modules 608 concentrically-arranged with one another and positioned above and/or below the mold assembly 502, respectively. In some embodiments, axially and/or radially adjacent modules 608 may be separate components or elements that are stacked atop one another, as in the sidewall 604, or concentrically-arranged side by side, as in the top and bottom plates 606 a,b. In other embodiments, axially and/or radially adjacent modules 608 may be coupled to provide one or more arrays of modules 608. For instance, in at least one embodiment, some or all of the axially and/or radially adjacent modules 608 may be threaded to each other. In other embodiments, axially and/or radially adjacent modules 608 may be mechanically fastened to each other using one or more mechanical fasteners (e.g., screws, bolts, snap fits, dovetail fittings, shrink fittings, etc.).
Each module 608 may have at least one thermal conduit 512 positioned therein. Positioning the thermal conduits 512 within the modules 608 can refer to physically embedding the thermal conduits 512 within the module 608, but may also refer to the thermal conduits 512 forming an integral part of the module 608, such as by defining or forming conduits directly in the material of the module 608. In yet other embodiments, the thermal conduits 512 may be positioned within a given module 608 by being arranged within a cavity 610 defined within the given module 608. The thermal conduits 512 may be configured to circulate the fluid 514 through portions of the enclosure 602 and thereby place the fluid 514 in thermal communication with the contents 506 of the infiltration chamber 312. Circulating the fluid 514 through the thermal conduits 512 may allow an operator to selectively manipulate the thermal profile of the contents 506 within the infiltration chamber 312.
While not shown, each thermal conduit 512 in the enclosure 602 may be fluidly coupled and otherwise connected to a heat exchanger (e.g., the heat exchanger 516 of FIGS. 5A-5C) and an associated pump (e.g., the pump 518 of FIGS. 5A-5C). The heat exchanger(s) may be configured to thermally condition the fluid 514 (i.e., heat or cool) depending on the application. In some embodiments, each thermal conduit 512 may be fluidly coupled to an independent heat exchanger such that each thermal conduit 512 may circulate the fluid 514 at a unique or predetermined temperature. In other embodiments, two or more thermal conduits 512 may form a set or grouping and may be in fluid communication with each other and in fluid communication with a common heat exchanger such that the thermal conduits 512 in the set circulate the fluid 514 at the same temperature. In yet other embodiments, all of the thermal conduits 512 may be fluidly coupled to the same heat exchanger such that each thermal conduit 512 circulates the fluid 514 at the same temperature.
In some embodiments, the bottom plate 606 b may be movable laterally C to provide space for a thermal heat sink 404 to move laterally C into place at a pre-determined time to initiate the cooling process. In other embodiments, the bottom plate 606 b may alternatively remain in place and a fluid 514 at a lower temperature or comprising a coolant may instead be circulated through the thermal conduits 512 to initiate the cooling process. In some embodiments, the bottom insulator 524 b may also be movable laterally C. The bottom insulator 524 b may be inserted after loading the mold assembly 502 into the enclosure 602 to prevent direct contact of the heating modules 608 of the sidewall(s) 604 with the thermal heat sink 404 and to otherwise hold the mold assembly 502 in place as the bottom plate 606 b is moved laterally C to make room for the thermal heat sink 404.
In some embodiments, the insulation assembly 520 may be disposed about the enclosure 504 such that one or both of the sidewall(s) 604 and the top plate 606 a (if used) is in direct contact with the enclosure 504. In other embodiments, a small gap 612 may separate the insulation assembly 520 from adjacent portions of the enclosure 504. In some embodiments, the gap 612 may be fairly small or miniscule, such as on the order of a few millimeters or less. In other embodiments, however, the gap 612 may be greater than a few millimeters, without departing from the scope of the disclosure. The gap 612 may prove advantageous not only in allowing the insulation assembly 520 to fit around the enclosure 504, but also in accommodating heat transfer between the two components via radiation (and possibly convection) rather than conduction. As will be appreciated, the size of the gap 612 may vary depending on the application.
Furthermore, a thermal barrier (not shown) may be applied to an outer surface of the enclosure 602 and/or to an inner surface of the insulation assembly 520. The thermal barrier may provide resistance to radiation or conduction heat transfer between the mold assembly 502 and the exterior of the system 600, depending on the size of gap 612 and the thermal barrier. For example, a large initial gap may be partially filled with the thermal barrier to produce the resulting gap 612. Alternatively, gap 612 may be completely filled with thermal barrier material. Suitable materials that may be used as the thermal barrier include, but are not limited to, a ceramic-fiber blanket, aluminum oxide, aluminum nitride, silicon carbide, silicon nitride, quartz, titanium carbide, titanium nitride, borides, carbides, nitrides, and oxides. The material barrier may further include, but is not limited to, materials in the form of woven fabrics, bulked fabrics, sheets, bricks, stones, blocks, cast shapes, molded shapes, foams, sprayed insulation, and the like, any hybrid thereof, or any combination thereof. The thermal barrier may be applied via a variety of processes or techniques including, but not limited to, electron beam physical vapor deposition, air plasma spray, high velocity oxygen fuel, electrostatic spray assisted vapor deposition, and direct vapor deposition. In at least one embodiment, a gas may be used to fill the gap 612.
Referring now to FIGS. 7A-7F, illustrated are cross-sectional views of various exemplary modules 608, according to one or more embodiments. Similar to the component parts of the enclosure 504 of FIGS. 5A-5C, the modules 608 of the enclosure 604 of FIG. 6 may be made of suitable materials including, but not limited to, graphite, alumina (Al₂O₃), a metal, a ceramic, and any combination thereof.
In FIG. 7A, the module 608 is the same as generally depicted in FIG. 6 and may include a thermal conduit 512 positioned therein. More particularly, the thermal conduit 512 may be arranged within the cavity 610 defined within the module 608. The cross-sectional shape of the cavity 610 in FIG. 7A is square, but may alternatively exhibit any other cross-sectional shape. For instance, in FIG. 7B, the cavity 610 is depicted as being generally circular to accommodate the thermal conduit 512 and with a much smaller gap between the thermal conduit 512 and the wall of the cavity 610. In FIG. 7C, the cavity 610 is omitted and the thermal conduit 512 is instead embedded directly within the module 608 or the thermal conduit 512 is defined in the material of the module 608 and thereby forms an integral part thereof. As will be appreciated, the cavity 610 may prove advantageous in accommodating thermal expansion mismatches between the thermal conduit 512 and the material of the module 608, which could otherwise compromise the integrity of the module 608. Additionally, the space inside the cavity 610 not occupied by the thermal conduit 512 can be filled with a suitable material to enhance or control the rate of heat transfer between the thermal conduit 512 and module 608. This material can be a solid or a fluid. If a fluid is used, it can be stationary or coupled to a pump 518 (FIGS. 5A-5C) and/or heat exchanger 516 (FIGS. 5A-5C), similar to a fluid 514 in a thermal conduit 512.
In FIGS. 7D-7F, the modules 608 are comprised of at least two different materials. For example, a first portion 702 a of the module 608 may be made of a first material, such as graphite, and a second portion 702 b of the module may be made of a second material, such as alumina. The first portion 702 a may be arranged adjacent the mold assembly 502 (FIGS. 5A-5C and 6) and the second portion 702 b may be arranged distal to the mold assembly 502. As will be appreciated, such embodiments may prove useful since the graphite material of the first portion 702 a is more conductive than the alumina material of the second portion 702 b, which may instead act as an insulating material, and thereby better facilitate a desired thermal profile. Moreover, such designs could facilitate construction and repair of the modules 608 where one of the portions 702 a,b or the thermal conduit 512 is replaced and/or refurbished while the other of the portions 702 a,b remains unchanged.
It should be noted that while the modules 608 are shown as having a generally square cross-section, one or more of the modules 608 may alternatively exhibit other cross-sectional shapes, such as circular or any other polygonal shape. In some embodiments, for example, an array of thermal conduits 512 may be arranged in a sheet-like configuration and placed between rectangles of a conduction material (on the inner side) and an insulating material (on the outer side), without departing from the scope of the disclosure.
Referring to FIGS. 8A and 8B, illustrated are cross-sectional views of various additional exemplary modules 608, according to one or more embodiments. In some embodiments, a single module 608 may have multiple thermal conduits 512 positioned therein and, more particularly, within the cavity 610. In FIGS. 8A-8B, there are six thermal conduits 512 depicted as being positioned within the cavity 610, but could alternatively accommodate more or less than six thermal conduits 512. Such modules 608 may prove useful in providing thermal energy to the sides of the mold assembly 502 (FIGS. 5A-5C and 6) and thereby being able to selectively vary the thermal profile along the height A (FIG. 5A) of the mold assembly 502. Moreover, as depicted in FIG. 8B, such a design may employ the first portion 702 a made of the first material and the second portion 702 b made of the second material.
In any of the integrated heat-exchanging mold systems 500 a-c, 600 described herein, the furnace 402 (FIG. 4A) and/or the insulation enclosure 406 (FIGS. 4B and 4C) may be omitted if desired. Instead, the systems 500 a-c, 600 as described herein may be configured to undertake both the heating (i.e., infiltration) and cooling cycles for the infiltrated downhole tool being fabricated within the mold assembly 502. In exemplary operation, the thermal conduits 512 disposed at or near the bottom of the mold assembly 502 may be activated first and otherwise circulate a high-temperature fluid 514. The high-temperature fluid 514 may begin to heat the matrix reinforcement materials 318 (FIG. 3) in the bottom of the mold assembly 502 before the binder material 324 (FIG. 3). At a particular time or a predetermined temperature, the thermal conduits 512 adjacent the binder material 324 may be activated to allow the binder material 324 to melt and infiltrate the matrix reinforcement materials 318.
Upon reaching a suitable temperature at a given location in the mold assembly 502, the bottom plate 606 b and its associated thermal conduits 512 may be moved laterally C (FIGS. 5C and 6) to accommodate the thermal heat sink 404 (FIGS. 4B-4C and 6) directly under the mold assembly 502. At this point, the temperature of the fluid 514 in the thermal conduits 512 arranged along the sides of the mold assembly 502 may be gradually decreased sequentially, starting at the bottom and working toward the top. As a result, a controlled directional cooling of the mold assembly 502 and its molten contents 506 (FIGS. 5A-5C and 6) may be achieved.
In any of the integrated heat-exchanging mold systems 500 a-c, 600 described herein, the thermal conduits 512 may alternatively be comprised of a thermal heating element in thermal communication with the infiltration chamber 312. The thermal heating element may be any device or mechanism configured to impart thermal energy to the contents 506 within the infiltration chamber 312. For example, the thermal heating element may include, but is not limited to, a heating element, a radiant heater, an electric heater, an infrared heater, an induction heater, one or more induction coils, a heating band, one or more heated coils, resistive heating elements, a refractory and conductive metal coil, strip, or bar, or any combination thereof. Upon being activated, a flow of electrical current, magnetic current, electrons, or the like may conduct through the thermal heating element to produce heat that may be transferred to the mold assembly 502.
In such embodiments, the thermal conduits 512 in any of the integrated heat-exchanging mold systems 500 a-c, 600 may comprise a single thermal heating element array and thereby form a spiraling or coiled single thermal heating element when viewed from a top view. In such embodiments, the thermal heating element may be controlled via a single lead (not shown) connected to a power source that controls the thermal heating element. In other embodiments, however, the thermal heating elements may comprise a collection of thermal heating elements that may be controlled together, or two or more sets of thermal heating elements that may be controlled independent of each other. In yet other embodiments, the thermal heating elements may comprise individual and discrete thermal heating elements that are each powered independent of the others. In such embodiments, each thermal heating element would require connection to a corresponding discrete lead to control and power the corresponding thermal heating elements. As will be appreciated, such embodiments may prove advantageous in allowing an operator to vary an intensity or heat output of each thermal heating element independently, and thereby produce a desired heat gradient within the mold 302.
Embodiments disclosed herein include:
A. An integrated heat-exchanging mold system for fabricating an infiltrated downhole tool, the mold system including a mold assembly that defines an infiltration chamber to receive and contain matrix reinforcement materials and a binder material used to form the infiltrated downhole tool, a heat-exchanging enclosure disposed about at least a portion of an exterior of the mold assembly, the heat-exchanging enclosure comprising one or more component parts that include at least one sidewall extending along a height of the mold assembly, and one or more thermal conduits positioned within the one or more component parts, including the at least one sidewall, and thereby placed in thermal communication with the infiltration chamber.
B. A method for fabricating an infiltrated downhole tool, the method including arranging a heat-exchanging enclosure about at least a portion of an exterior of a mold assembly that defines an infiltration chamber, the heat-exchanging enclosure comprising one or more component parts that include at least one sidewall extending along a height of the mold assembly, placing one or more thermal conduits in thermal communication with the infiltration chamber, the one or more thermal conduits being positioned within the one or more component parts including the at least one sidewall, and actively manipulating a thermal profile of contents within the infiltration chamber with the one or more thermal conduits.
C. A method that includes introducing a drill bit into a wellbore, the drill bit being formed in an integrated heat-exchanging mold system that includes a mold assembly defining an infiltration chamber, and a heat-exchanging enclosure having one or more component parts that include at least one sidewall, wherein forming the drill bit comprises arranging the heat-exchanging enclosure about at least a portion of an exterior of the mold assembly, the at least one sidewall extending along a height of the mold assembly, placing one or more thermal conduits in thermal communication with the infiltration chamber, the one or more thermal conduits being positioned within the one or more component parts including the at least one sidewall and actively manipulating a thermal profile of contents within the infiltration chamber with the one or more thermal conduits and drilling a portion of the wellbore with the drill bit.
Each of embodiments A, B, and C may have one or more of the following additional elements in any combination: Element 1: wherein the infiltrated downhole tool is selected from the group consisting of a drill bit, a cutting tool, a non-retrievable drilling component, a drill bit body associated with casing drilling of wellbores, a drill-string stabilizer, a cone for a roller-cone drill bit, a model for forging dies used to fabricate support arms for roller-cone drill bits, an arm for a fixed reamer, an arm for an expandable reamer, an internal component associated with expandable reamers, a rotary steering tool, a logging-while-drilling tool, a measurement-while-drilling tool, a side-wall coring tool, a fishing spear, a washover tool, a rotor, a stator, a blade for a downhole turbine, a housing for a downhole turbine, and any combination thereof. Element 2: wherein the one or more component parts further include at least one of a top plate positioned above the mold assembly and a bottom plate positioned below the mold assembly, and wherein the one or more thermal conduits are further positioned within at least one of the top plate and the bottom plate. Element 3: wherein the one or more thermal conduits circulate a fluid through the one or more component parts, the fluid being selected from the group consisting of a gas, water, steam, an oil, a coolant, a molten metal, a molten metal alloy, a fluidized bed, or a molten salt. Element 4: further comprising a heat exchanger fluidly coupled to the one or more thermal conduits for thermally conditioning the fluid, and a pump fluidly coupled to the heat exchanger and the one or more thermal conduits to circulate the fluid through the one or more component parts. Element 5: wherein the one or more thermal conduits comprise a single thermal conduit that forms a spiral or helical array. Element 6: wherein the one or more thermal conduits comprise at least a first set of thermal conduits and a second set of thermal conduits, and wherein the first set of thermal conduits is independently operable from the second set of thermal conduits. Element 7: wherein the one or more thermal conduits comprise a plurality of individual thermal conduits, and wherein each individual thermal conduit is independently operable. Element 8: further comprising an outer insulation assembly disposed about at least a portion of an exterior of the heat-exchanging enclosure and including at least a sidewall insulator. Element 9: wherein the outer insulation assembly further includes at least one of a top insulator positioned above the mold assembly and a bottom insulator positioned below the mold assembly. Element 10: wherein the heat-exchanging enclosure comprises a plurality of heat-exchanging modules and at least one of the one or more thermal conduits is positioned within each heat-exchanging module. Element 11: wherein the at least one of the one or more thermal conduits is positioned within a cavity defined in one or more of the plurality of heat-exchanging modules. Element 12: wherein each heat-exchanging module is made of at least one material selected from the group consisting of graphite, alumina, a metal, a ceramic, and any combination thereof. Element 13: wherein the one or more thermal conduits comprise one or more thermal heating elements selected from the group consisting of a heating element, a radiant heater, an electric heater, an infrared heater, an induction heater, one or more induction coils, a heating band, one or more heated coils, a resistive heating element, a refractory and conductive metal coil, strip, or bar, or any combination thereof. Element 14: wherein the one or more thermal heating elements comprise a single thermal heating element that forms a spiral array. Element 15: wherein the one or more thermal heating elements comprises at least a first set of thermal heating elements and a second set of thermal heating elements, and wherein the first and second sets of thermal heating elements are controlled independent of each other. Element 16: wherein the one or more thermal heating elements comprises a plurality of individual thermal heating elements that are each powered independent of each other.
Element 17: wherein actively manipulating the thermal profile of the contents within the infiltration chamber with the one or more thermal conduits comprises heating matrix reinforcement materials and a binder material disposed within the infiltration chamber so that the binder material liquefies and infiltrates the matrix reinforcement materials. Element 18: wherein the contents within the infiltration chamber are molten contents and actively manipulating the thermal profile of the contents within the infiltration chamber with the one or more thermal conduits comprises selectively cooling portions of the molten contents with the one or more thermal conduits, and varying a thermal profile of the molten contents with the one or more thermal conduits and thereby facilitating directional solidification of the molten contents. Element 19: wherein selectively cooling portions of the molten contents with the one or more thermal conduits comprises generating a thermal gradient along an axial height of the mold assembly with the one or more thermal conduits. Element 20: wherein the one or more component parts further include at least one of a top plate positioned above the mold assembly and a bottom plate positioned below the mold assembly, and wherein placing the one or more thermal conduits in thermal communication with the infiltration chamber comprises placing the one or more thermal conduits positioned within at least one of the top plate and the bottom plate in thermal communication with the infiltration chamber. Element 21: wherein the one or more thermal conduits comprises at least a first set of thermal conduits and a second set of thermal conduits, the method further comprising operating the first and second sets of thermal conduits independently. Element 22: wherein the one or more thermal conduits comprises a plurality of individual thermal conduits, the method further comprising operating each individual thermal conduit independently. Element 23: further comprising arranging an outer insulation assembly about at least a portion of an exterior of the heat-exchanging enclosure, the outer insulation assembly including at least a sidewall insulator, and insulating the mold assembly and the heat-exchanging enclosure with the outer insulation assembly. Element 24: wherein the outer insulation assembly further includes a top insulator positioned above the mold assembly, the method further comprising simultaneously raising the sidewall insulator and the top insulator and thereby exposing portions of the heat-exchanging enclosure, and cooling the mold assembly as the sidewall insulator and the top insulator are raised. Element 25: wherein the outer insulation assembly further includes a bottom insulator positioned below the mold assembly, the method further comprising moving the bottom insulator laterally with respect to the mold assembly, and arranging a thermal heat sink beneath the mold assembly. Element 26: wherein the one or more thermal conduits contain a fluid, and wherein placing the one or more thermal conduits in thermal communication with the infiltration chamber comprises circulating the fluid through the one or more thermal conduits and thereby placing the fluid in thermal communication with the infiltration chamber. Element 27: wherein the one or more thermal conduits comprise one or more thermal heating elements, and wherein placing the one or more thermal conduits in thermal communication with the infiltration chamber comprises placing the one or more thermal heating elements in thermal communication with the infiltration chamber.
By way of non-limiting example, exemplary combinations applicable to A, B, and C include: Element 8 with Element 9; Element 11 with Element 12; Element 13 with Element 14; Element 13 with Element 15; Element 13 with Element 16; Element 18 with Element 19; Element 23 with Element 24; and Element 23 with Element 25.
Therefore, the disclosed systems and methods are well adapted to attain the ends and advantages mentioned as well as those that are inherent therein. The particular embodiments disclosed above are illustrative only, as the teachings of the present disclosure may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. Furthermore, no limitations are intended to the details of construction or design herein shown, other than as described in the claims below. It is therefore evident that the particular illustrative embodiments disclosed above may be altered, combined, or modified and all such variations are considered within the scope of the present disclosure. The systems and methods illustratively disclosed herein may suitably be practiced in the absence of any element that is not specifically disclosed herein and/or any optional element disclosed herein. While compositions and methods are described in terms of “comprising,” “containing,” or “including” various components or steps, the compositions and methods can also “consist essentially of” or “consist of” the various components and steps. All numbers and ranges disclosed above may vary by some amount. Whenever a numerical range with a lower limit and an upper limit is disclosed, any number and any included range falling within the range is specifically disclosed. In particular, every range of values (of the form, “from about a to about b,” or, equivalently, “from approximately a to b,” or, equivalently, “from approximately a-b”) disclosed herein is to be understood to set forth every number and range encompassed within the broader range of values. Also, the terms in the claims have their plain, ordinary meaning unless otherwise explicitly and clearly defined by the patentee. Moreover, the indefinite articles “a” or “an,” as used in the claims, are defined herein to mean one or more than one of the element that it introduces. If there is any conflict in the usages of a word or term in this specification and one or more patent or other documents that may be incorporated herein by reference, the definitions that are consistent with this specification should be adopted.
As used herein, the phrase “at least one of” preceding a series of items, with the terms “and” or “or” to separate any of the items, modifies the list as a whole, rather than each member of the list (i.e., each item). The phrase “at least one of” allows a meaning that includes at least one of any one of the items, and/or at least one of any combination of the items, and/or at least one of each of the items. By way of example, the phrases “at least one of A, B, and C” or “at least one of A, B, or C” each refer to only A, only B, or only C; any combination of A, B, and C; and/or at least one of each of A, B, and C.

Claims

What is claimed is:

1. An integrated heat-exchanging mold system for fabricating an infiltrated downhole tool, comprising:

a mold assembly that defines an infiltration chamber to receive and contain matrix reinforcement materials and a binder material used to form the infiltrated downhole tool;

a heat-exchanging enclosure disposed about at least a portion of an exterior of the mold assembly, the heat-exchanging enclosure comprising one or more component parts that include at least one sidewall extending along a height of the mold assembly; and

one or more thermal conduits positioned within the one or more component parts, including the at least one sidewall, and thereby placed in thermal communication with the infiltration chamber.

2. The integrated heat-exchanging mold system of claim 1, wherein the infiltrated downhole tool is selected from the group consisting of a drill bit, a cutting tool, a non-retrievable drilling component, a drill bit body associated with casing drilling of wellbores, a drill-string stabilizer, a cone for a roller-cone drill bit, a model for forging dies used to fabricate support arms for roller-cone drill bits, an arm for a fixed reamer, an arm for an expandable reamer, an internal component associated with expandable reamers, a rotary steering tool, a logging-while-drilling tool, a measurement-while-drilling tool, a side-wall coring tool, a fishing spear, a washover tool, a rotor, a stator, a blade for a downhole turbine, and a housing for a downhole turbine.

3. The integrated heat-exchanging mold system of claim 1, wherein the one or more component parts further include at least one of a top plate positioned above the mold assembly and a bottom plate positioned below the mold assembly, and wherein the one or more thermal conduits are further positioned within at least one of the top plate and the bottom plate.

4. The integrated heat-exchanging mold system of claim 1, wherein the one or more thermal conduits circulate a fluid through the one or more component parts, the fluid being selected from the group consisting of a gas, water, steam, an oil, a coolant, a molten metal, a molten metal alloy, a fluidized bed, a molten salt, and any combination thereof.

5. The integrated heat-exchanging mold system of claim 1, further comprising:

a heat exchanger fluidly coupled to the one or more thermal conduits for thermally conditioning the fluid; and

a pump fluidly coupled to the heat exchanger and the one or more thermal conduits to circulate the fluid through the one or more component parts.

6. The integrated heat-exchanging mold system of claim 1, wherein the one or more thermal conduits comprise a single thermal conduit that forms a spiral or helical array.

7. The integrated heat-exchanging mold system of claim 1, wherein the one or more thermal conduits comprise at least a first set of thermal conduits and a second set of thermal conduits, and wherein the first set of thermal conduits is independently operable from the second set of thermal conduits.

8. The integrated heat-exchanging mold system of claim 1, wherein the one or more thermal conduits comprise a plurality of individual thermal conduits, and wherein each individual thermal conduit is independently operable.

9. The integrated heat-exchanging mold system of claim 1, further comprising an outer insulation assembly disposed about at least a portion of an exterior of the heat-exchanging enclosure and including at least a sidewall insulator.

10. The integrated heat-exchanging mold system of claim 9, wherein the outer insulation assembly further includes at least one of a top insulator positioned above the mold assembly and a bottom insulator positioned below the mold assembly.

11. The integrated heat-exchanging mold system of claim 1, wherein the heat-exchanging enclosure comprises a plurality of heat-exchanging modules and at least one of the one or more thermal conduits is positioned within each heat-exchanging module.

12. The integrated heat-exchanging mold system of claim 11, wherein the at least one of the one or more thermal conduits is positioned within a cavity defined in one or more of the plurality of heat-exchanging modules.

13. The integrated heat-exchanging mold system of claim 11, wherein each heat-exchanging module is made of at least one material selected from the group consisting of graphite, alumina, a metal, a ceramic, and any combination thereof.

14. The integrated heat-exchanging mold system of claim 1, wherein the one or more thermal conduits comprise one or more thermal heating elements selected from the group consisting of a heating element, a radiant heater, an electric heater, an infrared heater, an induction heater, one or more induction coils, a heating band, one or more heated coils, a resistive heating element, a refractory and conductive metal coil, strip, or bar, or any combination thereof.

15. The integrated heat-exchanging mold system of claim 14, wherein the one or more thermal heating elements comprise a single thermal heating element that forms a spiral array.

16. The integrated heat-exchanging mold system of claim 14, wherein the one or more thermal heating elements comprises at least a first set of thermal heating elements and a second set of thermal heating elements, and wherein the first and second sets of thermal heating elements are controlled independent of each other.

17. The integrated heat-exchanging mold system of claim 14, wherein the one or more thermal heating elements comprises a plurality of individual thermal heating elements that are each powered independent of each other.

18. A method for fabricating an infiltrated downhole tool, comprising:

arranging a heat-exchanging enclosure about at least a portion of an exterior of a mold assembly that defines an infiltration chamber, the heat-exchanging enclosure comprising one or more component parts that include at least one sidewall extending along a height of the mold assembly;

placing one or more thermal conduits in thermal communication with the infiltration chamber, the one or more thermal conduits being positioned within the one or more component parts including the at least one sidewall; and

actively manipulating a thermal profile of contents within the infiltration chamber with the one or more thermal conduits.

19. The method of claim 18, wherein actively manipulating the thermal profile of the contents within the infiltration chamber with the one or more thermal conduits comprises heating matrix reinforcement materials and a binder material disposed within the infiltration chamber so that the binder material liquefies and infiltrates the matrix reinforcement materials.

20. The method of claim 18, wherein the contents within the infiltration chamber are molten contents and actively manipulating the thermal profile of the contents within the infiltration chamber with the one or more thermal conduits comprises:

selectively cooling portions of the molten contents with the one or more thermal conduits; and

varying a thermal profile of the molten contents with the one or more thermal conduits and thereby facilitating directional solidification of the molten contents.

21. The method of claim 20, wherein selectively cooling portions of the molten contents with the one or more thermal conduits comprises generating a thermal gradient along an axial height of the mold assembly with the one or more thermal conduits.

22. The method of claim 18, wherein the one or more component parts further include at least one of a top plate positioned above the mold assembly and a bottom plate positioned below the mold assembly, and wherein placing the one or more thermal conduits in thermal communication with the infiltration chamber comprises placing the one or more thermal conduits positioned within at least one of the top plate and the bottom plate in thermal communication with the infiltration chamber.

23. The method of claim 18, wherein the one or more thermal conduits comprises at least a first set of thermal conduits and a second set of thermal conduits, the method further comprising operating the first and second sets of thermal conduits independently.

24. The method of claim 18, wherein the one or more thermal conduits comprises a plurality of individual thermal conduits, the method further comprising operating each individual thermal conduit independently.

25. The method of claim 18, further comprising:

arranging an outer insulation assembly about at least a portion of an exterior of the heat-exchanging enclosure, the outer insulation assembly including at least a sidewall insulator; and

insulating the mold assembly and the heat-exchanging enclosure with the outer insulation assembly.

26. The method of claim 25, wherein the outer insulation assembly further includes a top insulator positioned above the mold assembly, the method further comprising:

simultaneously raising the sidewall insulator and the top insulator and thereby exposing portions of the heat-exchanging enclosure; and

cooling the mold assembly as the sidewall insulator and the top insulator are raised.

27. The method of claim 25, wherein the outer insulation assembly further includes a bottom insulator positioned below the mold assembly, the method further comprising:

moving the bottom insulator laterally with respect to the mold assembly; and

arranging a thermal heat sink beneath the mold assembly.

28. The method of claim 18, wherein the one or more thermal conduits contain a fluid, and wherein placing the one or more thermal conduits in thermal communication with the infiltration chamber comprises circulating the fluid through the one or more thermal conduits and thereby placing the fluid in thermal communication with the infiltration chamber.

29. The method of claim 18, wherein the one or more thermal conduits comprise one or more thermal heating elements, and wherein placing the one or more thermal conduits in thermal communication with the infiltration chamber comprises placing the one or more thermal heating elements in thermal communication with the infiltration chamber.

30. A method, comprising:

introducing a drill bit into a wellbore, the drill bit being formed in an integrated heat-exchanging mold system that includes a mold assembly defining an infiltration chamber, and a heat-exchanging enclosure having one or more component parts that include at least one sidewall, wherein forming the drill bit comprises:

arranging the heat-exchanging enclosure about at least a portion of an exterior of the mold assembly, the at least one sidewall extending along a height of the mold assembly;

actively manipulating a thermal profile of contents within the infiltration chamber with the one or more thermal conduits; and

drilling a portion of the wellbore with the drill bit.