• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
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  • 优先权
    • 专利摘要:
    The present invention relates to a molten metal processing apparatus selected from a pump, a degasser, a flow injector, and a refuse submersion device constructed to include at least one element comprised of c/c composite.
    公开号:BR112017002708B1
    申请号:R112017002708-9
    申请日:2015-08-13
    公开日:2021-06-22
    发明作者:Richard S. Henderson；Jason Tetkoskie；Lennard Lutes；Jon Tipton
    申请人:Pyrotek, Inc；
    IPC主号:
    专利说明:

    [001] The present application claims the benefit of United States Provisional Application No. 62/037,387, filed August 14, 2014, the invention of which is incorporated herein by reference. BACKGROUND
    [002] The present invention relates to the processing of molten metal. It finds particular application in conjunction with molten metal pumps, submersion devices, degassing equipment, and the like, and will be described with particular reference thereto. However, it is to be appreciated that the present invention is also susceptible to other similar applications.
    [003] Aluminum is the third most abundant element (after oxygen and silicon), and the most abundant metal in the earth's crust. It makes up about 8% by weight of the Earth's solid surface. Aluminum is notable for being a low density metal and for its ability to resist corrosion due to the phenomenon of passivation. Components made from aluminum and its alloys are vital to the worldwide production of structural materials. Aluminum is particularly valuable because of its additionally advantageous ability to be readily recycled.
    [004] Aluminum is typically either melted and cast into a finished product, or cast into an ingot for transportation and eventual re-melting and casting into the desired end product. Special handling equipment has been developed to facilitate the melting, processing, and transportation of molten aluminum.
    [005] Although the present invention has been associated with aluminum, it is noted that the equipment described herein may also be suitable for use with other molten metals (and their salts), including zinc, magnesium, and nickel, as examples.
    [006] The process of handling and recycling molten metal is complex. It requires metal smelting equipment, pumps for circulating molten metal, devices for submerging scrap metal parts, devices for removing impurities (eg filtration and degassing), devices for introducing flow and other alloying agents, and devices for transporting molten metal.
    [007] In a typical melting operation, a melting furnace is provided with an enclosed fireplace and a connected open cavity cavity. A pump or other flow of molten metal that induces the appliance is positioned in the side cavity, and causes molten metal to circulate inside the fireplace. The side cavity can include a pump cavity and a melt compartment which can be further divided into a loading cavity and an impurity cavity. Metal can be melted by introducing solid bars to the main fireplace, and/or by adding metal pieces to the side cavity.
    [008] The charge cavity can be used to melt scrap metal. Various pieces of equipment have been developed to help submerge the scrap parts, and are referred to here as scrap submersion devices. The impurity cavity can be used to remove contaminants. Furthermore, scrap metal is usually contaminated with organic and inorganic contaminants. Organic contaminants most commonly consist of residues from various types of oils, coatings, or paints, and the like. Inorganic contaminants include dust particles, pigments, smaller amounts of various scrap metals other than the parent metal, and the like. Aluminum scrap will also typically contain varying amounts of metal oxides. Most of the contaminants will float on top of the molten metal bath, or will form dross, or a slag-like shell of inorganic contaminants in the molten metal that can be stripped from the metal in accordance with well-established techniques.
    [009] In processing molten metals, eg aluminum or zinc, a commonly employed piece of equipment is a circulation pump to create molten metal flow in a furnace. In addition, it is often necessary to pump molten metal from one vessel to another. When molten metal needs to be removed from a vessel by lifting it over a retaining wall, a so-called transfer pump is often used. These may include traditional transfer pump styles shown, for example, in United States Patent 5,947,705 (herein incorporated by reference), or an overflow transfer system of the type shown in United States Published Application US 2013/ 0101424 (herein incorporated by reference), or a washer/ladle transfer system of the type shown in U.S. Patent 8,337,746 (herein incorporated by reference).
    [0010] Very typical of this situation is where the transfer pump is placed in the charge cavity of a molten metal furnace to remove molten metal from the furnace, perhaps for introduction into a ladle and from there to mold casters. In the aluminum recycling industry, magnesium removal has become a particular focus. The ability to remove magnesium from molten aluminum is made possible by a favorable chemical reaction between magnesium and chlorine. A gas injection pump can be used for this proposal.
    [0011] The degassing apparatus can be used to increase the quality of molten metal before performing a casting operation. In such a degassing operation, a large amount of finely bubbled inert gas, such as argon gas, or nitrogen gas, is introduced into the molten metal so that dissolved gas and non-metallic inclusions are entrained or captured by the inert gas bubbles, which are floated for removal. Typically, inert gas is injected into the molten metal via a rotating shaft and impeller assembly disposed below the surface of the molten metal. In addition, the apparatus exits for introducing flux, typically chlorine and/or chlorine salts, into the molten metal. This apparatus may include rotary impeller/shaft combinations through which inert gas and flow can be introduced. United States Patents 3,767,382 and 8,025,712 are examples of flow injectors and the invention of each is incorporated herein by reference.
    [0012] As one skilled in the art will appreciate, the environment in which molten metal processing equipment operates is extraordinarily harsh. For example, aluminum and magnesium melted above 1200°F. Consequently, not all materials work on these types of molten metals. In addition, the density of these liquids can provide significant mechanical stress on equipment used to move molten metal. In addition, the zone in which the equipment transitions from molten metal to the surrounding atmosphere is a highly oxidizing, high temperature environment that makes many materials unsuitable for use. Consequently, until now, the primary materials used to build molten metal processing equipment, at least the elements operating below the melt line, have been graphite, silicon nitride, and silicon carbide. Each of these materials suffers from such problems as machinability, strength, susceptibility to thermal shock, and high cost. BRIEF DESCRIPTION
    [0013] The present invention is directed to the concept of using an alternative material in the construction of various components of molten metal processing equipment and, in addition, representative examples of improved components that can be constructed therefrom.
    [0014] According to a first embodiment, a molten metal processing apparatus selected from a pump, a degasser, a flow injector, and a reject submersion device, is provided. The apparatus is constructed to include at least one element comprised of C/C composite.
    According to a further exemplary embodiment, the present invention is directed to an apparatus, such as a molten metal pump, degasser, flow injector, and/or refuse submersion device. The apparatus may include a motor, a shaft that engages the motor at a first end, and an impeller at a second end, in which at least one component intended to be disposed below, or transited through a molten metal surface, is comprised. of a C/C composite material.
    [0016] According to a further embodiment, a method of processing a molten metal is provided. The method includes the steps of (i) impregnating a carbon fiber body with a resin; (ii) heating the body from step (i) to form a C/C composite; (iii) machining the C/C composite of step (ii) to form a component of a molten metal pump, degasser, or refuse submersion device; and, (iv) operating a pump, degasser, or refuse submersion device, including the component of step (iii) in processing molten metal. In addition, it may be desirable to include an optional oxidation resistance treatment after one of steps (ii) or (iii). BRIEF DESCRIPTION OF THE DRAWINGS
    [0017] Figure 1 is a schematic illustration of a typical molten metal furnace:
    [0018] Figure 2 is a perspective view of a molten metal furnace with partial section to illustrate a molten metal pump;
    [0019] Figure 3 is a side elevation view, partially in cross section, of a gas injection pump;
    [0020] Figure 4 is a side elevation view, partially in cross section, of a transfer pump;
    [0021] Figure 5 is an exploded view of an impeller including a C/C composite top plate;
    [0022] Figure 6 is a perspective view of a reciprocating transfer pump in a side cavity of the furnace;
    [0023] Figure 7 is a cross-sectional view of the transfer pump of Figure 6;
    [0024] Figure 8 is a side elevation view of a mold pump, partially in cross-section;
    [0025] Figure 9 is a perspective view of an alternative impeller shaft assembly suitable for use in the mold pump of Figure 8;
    [0026] Figure 10 is a side elevation view of a degassing apparatus;
    [0027] Figure 11 is a bottom plan view of a degassing impeller;
    [0028] Figure 12 is a bottom plan view of an impeller having a body constructed of graphite, and including wear regions having added C/C composite;
    [0029] Figure 13 is a top plan view of an alternative impeller configuration achievable using a C/C composite material;
    [0030] Figure 14 is a hybrid impeller of a style similar to Figure 13 having a graphite main body and C/C composite vanes; and
    [0031] Figure 15 is a cross-sectional view of a melting scrap apparatus. DETAILED DESCRIPTION
    [0032] In accordance with the present invention, it is contemplated that various components of molten metal processing equipment are partially or completely constructed of a carbon-carbon composite material (hereinafter C/C composite). C/C composites can be costly to produce, but provide a high strength-to-weight ratio and rigidity. C/C composites can also be impregnated with a corrosion resistant chemical of the type commonly used with graphite components, such as a solution including a phosphate-based oxidation retarder (see US Patent 4,439,491 as an example , the invention which is incorporated herein by reference). This is beneficial relative to, for example, high density graphite, which is not easily impregnated. C/C composites offer excellent combinations of thermal conductivity and stiffness. Also, C/C composites offer low density, high rigidity, low coefficient of thermal expansion, zero to little degassing, and a unique high temperature capability.
    [0033] C/C composites have thermal stability, high thermal shock resistance due to high thermal conductivity, and low thermal expansion behavior, that is, low thermal expansion coefficient. These materials are also characterized as having high hardness, strength and stiffness in high temperature applications. C/C composites can comprise carbon or graphite reinforcements mixed or contacted with matrix precursors to form a "green" composite, which is then carbonized to form the C/C composite. C/C composites may also comprise carbon or graphite reinforcements in which the matrix is introduced completely, or in part, by chemical vapor infiltration (CVI), or chemical vapor reaction (CVR).
    [0034] C/C composites can be produced from fibrous materials such as carbon fibers or carbon fiber precursors. In the course of manufacturing C/C composites, these fibrous materials are often mixed with binders. One type of such C/C composites are produced with chopped fibers mixed with thermoplastic tar-based binder in powder form. The mixture is placed in a mold where it is compacted and heated to form a preform, and the resulting preform is carbonized by heating.
    [0035] C/C composites are commercially available from companies such as Amoco, DuPont, Hercules, Celanese and others, and may take the form of fiber, chopped fiber, cloth or fabric, or cut cloth or fabric, which are referred to as molding composites. C/C composites can also take the form of continuous filament yarn, cut yarn, or tape produced from continuous filaments, and which are referred to as unidirectional fiber series. The yarns can be woven into desired shapes by interweaving, or by multidirectional weaving. The wire, cloth and/or tape can be wrapped or wrapped around a mandrel to form a variety of reinforcing shapes and orientations. The fibers can be wrapped in a dry state, or they can be impregnated with the desired matrix precursor prior to wrapping, winding, or stacking, to form what is commonly known as a prepreg. Such prepreg and fabric structure reinforcements are commercially available from a number of sources including Fiberite, Hexcel and Cytec. Carbon fiber reinforcements can be prepared from precursors such as polyacrylonitrile (PAN), rayon, or pitch.
    [0036] Matrix precursors that can be used to form C/C composites include liquid sources, such as phenolic resins and pitch, and gaseous sources, including hydrocarbons, such as methane, ethane, propane, and the like. Representative phenolics include, but are not limited to, phenolics sold under the commercially available trade designations USP39 and 91LD, such as supplied by Stuart-Ironsides of Willowbrook, Ill.
    [0037] C/C composites can be manufactured by a variety of techniques. Conventionally, resin impregnated carbon fibers are autoclaved or pressure molded into the desired shape in a tool or mold. The molded parts are heat treated in an inert environment at temperatures from approximately 1300°F (700°C) to 5250°F (2900°C) to convert the organic phases to carbon. The carbonized parts are then densified by carbon chemical vapor infiltration, or by multiple cycle re-impregnations with resins, as described above. Other manufacturing methods include hot pressing and chemical vapor infiltration of dry preforms. C/C composite fabrication methods that can be used in carrying out some of the necessary steps in the fabrication method are described in U.S. Pat. 3,174,895 and 3,462,289, which are incorporated herein by reference.
    [0038] Once the general shape of the C/C composite article is manufactured, the part can be readily machined to precise tolerances, on the order of about 0.1mm or less. Consequently, given the strength and machinability of C/C composites, in addition to the molding possible in the initial manufacturing process, C/C composites can be formed into highly precise shapes for components by machining. In this regard, the C/C composites of the present invention can provide advantageous fabrication relative to ceramics which have casting accuracy limitations and strength advantages relative to graphite.
    [0039] The C/C composites of the present description can have low friction characteristics at high temperatures by including a controlled amount of boron, for example. C/C composites of this type can be particularly useful as a bearing ring in a cast metal pump.
    [0040] An aluminum recycling furnace is described in United States Patent 6,217,823, incorporated herein by reference. Referring now to Figure 1, an aluminum recycling furnace 100 is shown. The furnace 100 includes a main fireplace component 120 that is heated, for example, with gas or oil burners, or by any other means known in the art. Adjacent, and in fluid communication with the fireplace 120, is the primary recycling area comprised of a pump cavity 140, a charge cavity 160, and an impurity cavity 180. Although not shown, the fireplace wall 120 opens. to pump cavity 140, which opens to charge cavity 160, which opens to impurity cavity 180, which, in turn, opens to fireplace 120, to allow for the circulation pattern shown by the arrows. The pump cavity receives a cast metal pump. The molten metal pump circulates molten metal from the fireplace 120 to the charge cavity 160, where scrap chips from the metal to be processed are deposited on the surface of the molten metal. Molten metal from charge cavity 160 flows into impurity cavity 180 where impurities in the form of slag are removed from the surface before the melt flows back into fireplace 120.
    [0041] Referring now to Figure 2, a molten metal circulation pump 200 within a recycle pump cavity 201 of furnace 203 is shown. This type of pump is more fully described in United States Patent 6,887,425, incorporated herein by reference. Pump 200 includes a plurality of posts 205 fixed to a base 207, and suspended from a motor assembly 209. An impeller (not shown) is disposed within the base 207, and connected to motor 210, via a shaft and coupling ( not shown). Pump 200 circulates molten metal from pump cavity 201 into charge cavity 211 and impurity cavity 213. The pump depicted in Figure 2 is commonly referred to as a circulation pump.
    [0042] In accordance with the present invention, and more fully described within the following discussion of various cast metal pump apparatus, it is considered that the casting line components below (ML) of the pump may be constructed wholly or in part from the materials of composite C/C. Similarly, in view of the excellent oxidation resistance achieved by chemical treatment, components at or near the ML can also be constructed of C/C composite materials. These components include the base housing, shaft, impeller, one or more bad bearing rings, and/or pump poles or sleeves.
    [0043] In certain molten metal processing operations, a gas injection pump of the type depicted in United States Patent 5,993,728, incorporated herein by reference, may be employed. Furthermore, when operating with certain molten metals, it may be necessary to perform gas injection to remove unwanted impurities. Referring now to Figure 3, a typical gas injection pump 301 is shown. The 301 pump includes a 302 suspension mount used for lifting and positioning the pump as needed inside the furnace. A motor 303 is supported by a motor assembly 304, supported by a support plate 306. The motor 303 is connected, via a coupling assembly 308, to a rotary shaft 310 secured to an impeller 312. A base assembly 314 is secured to the motor assembly 304 by a plurality of posts 316. Impeller 312 is rotatable within a pump chamber 318 and its rotation withdraws molten metal 319 in pump chamber 318 through an inlet 320, and discharges molten metal through a discharge passage 322. Bearing ring pairs 321 and 323 are cooperatively disposed on impeller 312, and on the wall of pumping chamber 318. An additional bearing ring 325 can be disposed on top of pumping chamber 318, and opposite. to a radial top edge of impeller 312.
    [0044] A reactive gas (such as chlorine) is provided to a gas injection tube 324 supported by a clamping mechanism 326 fixed to the support plate 306. The submerged end of the gas injection tube 324 is connected, via a tube plug 328, to the discharge passage 322. In addition to the C/C composite elements identified in Figure 2, the gas injection tube 324 and tube plug 328 may be constructed of a C/C composite material. Accordingly, pump components 301, which may advantageously be completely or partially constructed of a C/C composite material, include base assembly 314, impeller 312, posts 316, shaft 310, gas injection tube 324, tube cap 328 , and one or more bearing rings 321, 323 and 325.
    [0045] In addition to situations where molten metal is circulated by a circulation pump, or circulated and treated by a gas injection pump, there are circumstances where molten metal is removed from a furnace, and transferred remotely for further processing. An exemplary transfer pump is described in United States Patent 5,947,705, incorporated herein by reference.
    [0046] A typical transfer pump 401, as shown in Figure 4, includes a motor 411 attached to a rotary shaft 413 by a coupling assembly 415. Shaft 413 is attached at its lower end to a rotary impeller 417 that rotates on the interior of pumping chamber 418 within base 419. A bearing ring 421 is provided in the lower region of base 419 in a facing orientation with a bearing ring 423 disposed on a lower annular edge of impeller 417. A ring additional bearing 424 may be disposed in an upper region of base 419, facing an upper annular edge of impeller 417, to allow correct rotation of impeller. The 411 engine is supported and connected to the 419 base mount by a pair of 425 posts (only one of which is visible) that are secured to a 429 engine mount platform.
    [0047] A riser tube 451 has a first end disposed within an outlet 453 in the base 419, and is secured in an opening of the motor assembly 460, via a coupling adapter 465. A top end of the riser tube 451 includes a flange 455 to which an elbow (not shown) can be attached. Elbow engages transfer piping which allows molten metal to be moved to a remote location. In addition to the above articulated pump components which are suitable for construction of C/C composite materials, the transfer pump lift assembly can be constructed from them.
    [0048] Referring to Figure 5, an impeller including a C/C composite component is shown. Impeller 501 is a generally cylindrical shaped body of graphite or ceramic, and includes an upper face 502 having a recess 504 to accommodate a shaft. Top face 502 also includes inlets 505 to passages 506 that extend downwardly from the top face, and outwardly through a sidewall 508, for an outlet 509. A bearing ring 510 of a ceramic, such as silicon carbide, or C/C composite material, is provided surrounding the outer edge of a lower face 512. A C/C composite disc 513, is attached to the top surface 502 of the impeller 501, to improve the wear characteristics of the device (the disc 513 is shown both removed and attached in Figure 5).
    [0049] Of course, the shape of the impeller and/or the protective top plate is not limited to a cylindrical shape. Preferably, the use of a protective top or bottom plate of C/C composite material with impeller of any shape, including bird cage, reed, triangular, or any polygonal shape, is contemplated. Furthermore, it is contemplated that the entire impeller body may be constructed of a C/C composite material.
    [0050] Referring to Figures 6 and 7, a molten metal overflow transfer pump 630 is shown in association with a furnace 628. The pump assembly is more fully described in United States Patent Publication 2013/0101424, which is incorporated herein by reference. The pump 630 is suspended via metal framing 632 which rests on the walls of the furnace compartment 634. A motor 635 rotates a shaft 636 and attached impeller 638. A refractory body 640 forms an elongated generally cylindrical pump chamber or tube 641. refractory body can be formed, for example, from fused silica, silica carbide, C/C composite material, or combinations thereof. The body 640 includes an inlet 643 that receives the impeller 638. The impeller 638 may be constructed completely or partially of C/C composite material. Preferably, bearing rings (not shown) are provided to facilitate uniform wear and rotation of impeller 638 thereon. Bearing rings can be composite of C/C composite material.
    [0051] In operation, molten metal is withdrawn into the impeller through inlet 643, and forced upwardly into tube 641 in the form of a forced vortex ("balance"). A top of tube 641, a volute-shaped chamber 642 is provided to direct the molten metal vortex created by rotation of the impeller externally in the chute 644. The chute 644 can be joined/fitted with additional chute members, or tubing, to direct the molten metal to its desired location, such as a casting apparatus, ladle, or other mechanism, as known to those skilled in the art. The gutter can be formed or coated with a C/C composite material.
    [0052] Although centrifugal pumps operate satisfactorily for pumping molten metal, they have never been found acceptable as a means of filling molten metal molds. Preferably, this task has been left to electromagnetic pumps, and pressurized furnaces. Known centrifugal pumps generally control a molten metal flow rate and pressure by modulating the rotational rate of the impeller. However, this control mechanism experiences erratic control of the flow rate and pressure of molten metal when attempting to transfer molten metal into a mold, such as a shape mold. Erratic control of the flow of molten metal into the shape mold is especially prevalent when attempting to fill a shape mold for a complicated or intrinsically formed tool, or part. A centrifugal pump capable of filling mold forms has been described in United States Published Application 2014/0044520, which is incorporated herein by reference.
    [0053] With reference to Figure 8, a mold pump assembly 810 is illustrated. The assembly includes an elongated shaft 816 having a cylindrical shape having an axis of rotation that is generally perpendicular to the base member 820. The elongated shaft has a first end 828 that is adapted to attach to a motor (not shown) by a coupling (not shown), and a second end 830 which is connected to an impeller 822. The impeller 822 is rotatably positioned within the pump chamber 818 such that operation of the motor/coupling rotates the elongated shaft 816 which rotates the impeller 822 inside pump chamber 818.
    [0054] The base member 820 defines the pump chamber 818 that receives the impeller 822. The base member 820 is configured to structurally receive one or more refractory posts (not shown) within the passages 831. Each passage 831 is adapted to receiving a metal rod disposed within a refractory shielding component of the refractory post to rigidly attach to an engine mount (not shown). The engine mount supports the engine above cast metal.
    The impeller 822 is configured with a first axial edge 832 which is axially spaced from a second axial edge 834. The first and second axial edges 832, 834 are located peripherally about the circumference of the impeller 822. The pump chamber 818 includes a bearing assembly 835 having a first bearing ring 836 axially spaced from a second bearing ring 838. The first and second axial edges 832 and 834 face the bearing rings 836 and 838, respectively. The radial edges can be comprised of a silicon carbide bearing ring. The remainder of the impeller body 823 may be comprised of a C/C composite material. The first axial edge 832 is face-aligned with the first bearing ring 836, and the second axial edge 834 is face-aligned with the second bearing ring 838. The bearing rings are produced from a material, such as silicon carbide, having fictional bearing properties at high temperatures to prevent cyclical failure due to high frictional forces. The bearings are adapted to support rotation of the impeller 822 within the base member, such that the pump assembly 810 is at least substantially prevented from vibrating.
    [0056] The use of a C/C composite body has been particularly advantageous in a mold pump assembly where precise metering of molten metal quantities at a specified mold volume and shape is required. In this regard, historical use of a graphite main body has been found to develop wear on the radial surface, particularly where the graphite material engages the silicon carbide bearing ring. Such wear results in unpredictable molten metal flow and pressure at a selected engine RPM over time.
    [0057] Rotation of impeller 822 removes molten metal at inlet 848, and chamber 818, such that continued rotation of impeller 822 causes molten metal to be forced out of pump chamber 818 for a discharge (not shown) of the 820 base member that communicates with a mold. Although the illustrated pump includes a C/C composite material as the main impeller body, it is contemplated that any of the elements intended to be disposed in the molten metal may be constructed of a C/C composite material, including bearing rings.
    [0058] For example, Figure 9 represents an alternative impeller shaft arrangement for a mold pump. The arrangement is comprised of a shaft 916 having a motor mounting end 928 and an impeller mounting end 930. The shaft may be comprised of graphite, ceramic, or C/C composite material, or combinations thereof. The shaft may also include a sleeve of C/C composite material. The 922 impeller can be constructed completely of a C/C composite material. In this way, it is feasible to optionally eliminate the bearing rings.
    [0059] Figure 10 schematically illustrates a conventional structure of a continuous degassing apparatus. However, the use of C/C composite elements in batch degassing is equally applicable. In order to improve the dispersion of the gas throughout the molten metal, rotating injectors are commonly used, which provide shear action of the gas bubbles and agitation/intimate mixing of the process gas with the liquid metal. The degassing apparatus receives molten metal 1009 continuously through an inlet 1002. The upper opening of a degassing vessel 1001 is covered by a lid 1003 and, on the downstream side, a partition 1004 which extends downwardly in the so that it crosses direction. the flow of metal 1009 to prevent floating substances (suspended matter), including oxides etc., which can form impurities, from being drained off in the subsequent treatment process. Namely, partition 1004 extends downwardly, so that a relatively narrow passage of a predetermined flow area is formed between the bottom end of partition 1004 and the inner bottom wall of container 1001. Such an arrangement of partition 1004 can obtain a maximized residence time of molten metal in treatment chamber 1008 upstream of partition 1004, so that an extended duration of time of a degassing operation can be achieved. A rotary gas diffusion device 1005 is inserted through an opening made in the cap 1003, and is located in the molten metal in the degassing vessel 1001. The gas diffusion device 1005 has an impeller 1010 mounted to the rotating shaft 1012 located (immersed) in the molten metal, while being subjected to a rotational movement, so that the inert gas is ejected from the bottom of the gas diffusion device 1005, while a finely bubbled inert gas is diffused into the molten metal . A 1006 burner may be included to maintain a desired temperature. Impeller 1010 and optionally shaft 1012 can be constructed of a C/C composite material. An exemplary impeller is described in United States Patent 8,178,036, incorporated herein by reference. Similarly, a flow injector apparatus of the type depicted in U.S. Patents 3,767,382 and 8,025,712 can benefit from the construction of various components (eg, shaft and rotor) of a C/C composite material.
    [0060] Referring to Figure 11, an impeller 1120 constructed of C/C composite material is illustrated. The impeller is in the form of a rectangular prism having a face 1124, a face 1126, and side walls 1128, 1130, 1132, 1134. The impeller 1120 includes a gas discharge outlet 1136 that opens through the face 1124. discharge port 1136 constitutes a portion of a threaded opening 1138 that extends through impeller 1120, and that opens through faces 1124 and 1126. The shaft (not shown) includes a longitudinally extending bore that opens. through the discharge ends 1136. Faces 1124, 1126 are approximately parallel to each other as side walls 1128, 1132 and side walls 1130, 1134. Faces 1124, 1126 and side walls 1128, 1130, 1132, 1134 are surfaces planars defining sharp right angle corners 1139. It is also possible that the impeller 1120 may be triangular, pentagonal, or otherwise polygonal in plan view.
    [0061] A plurality of grooves 1152, 1154, 1156, 1158, 1160, 1162, 1164, 1166, 1168, 1170, 1172, 1174 extend radially externally from the hub 1150. Each groove extends from the hub to one respective sidewall, and respective slot is opened in the sidewall.
    [0062] Grooves 1152...1174 extend in impeller body 1120 from face 1124, and have a surface that is spaced apart and generally parallel to face 1126. Grooves 1152...1174 include longitudinal axes L ( which is also a symmetrical axis) which are aligned with each other, and which extend from one side to the opposite side. The axes are collinear with the threaded opening radius 1138 (that is, they extend through the center of the threaded opening).
    [0063] Figure 12 illustrates an alternative impeller 1220 in which the main body 1222 is constructed of graphite, and the corners 1239 receive insert 1241 constructed of C/C composite material. In addition, corners can constitute high wear surfaces that can benefit from longer live C/C composite even though the total unit cost is kept relatively low by the inclusion of a relatively low cost graphite main body.
    [0064] C/C composite parts can be secured to graphite, ceramic, or other C/C composite elements of molten metal processing equipment by mechanical means, adhesive means (cement, for example), or by means of a reactive bonding joint interlayer. The interlayer can be formed from fine particles of metal, carbide and carbon forming ingredients. Metals included in the composites can be selected from the group consisting of W, Ti, Si, Ta, Nb, Zr, Hf, V, Cr, and Mo. Tungsten is the preferred metallic ingredient in the joint composite. The reactive bonding layer can also contain one or more refractory composites as a filler material. Representative refractory compounds include TiB2, BN, B4C, SiC, TiC, MoSi2, WSi2. A tie layer can comprise a slurry produced from, for example, 10 grams of tungsten powder and 0.5 grams of carbon powder, and 12 milliliters of methanol. The parts to be joined with the bonding layer are heated in an argon atmosphere, and under a compressive pressure of 5 megapascals at a temperature of 1450-1580°C for a period of 10-30 minutes. The method includes the steps of: providing a first part of the C/C composite and a second part, wherein the second part has a surface that is complementary to a surface of the part of the C/C composite; providing a layer of a mixture of metal powder and carbon powder on the first complementary underlying surface; arranging the second C/C composite piece on the powder layer such that the second complementary underlying surface is matched to the first complementary underlying surface, thereby forming an assembly of the first C/C composite piece, the powder layer, and the second piece; place the assembly in a press and apply pressure to the assembly to press the two joined pieces together on their complementary surfaces; and applying an electrical current to the powder in the assembly to initiate an oxidation reduction reaction, thereby bonding the parts together.
    [0065] Referring to Figure 13, it is noted that traditional forms of molten metal impellers (including pump impellers, tailing submersion impellers, and degassing impellers) have been constrained by the strength of graphite and/or the machinability of ceramics. Consequently, by employing the C/C composite in impeller manufacture, it is considered that increased efficiency designs are achievable. For example, the configuration of Figure 13 constructed entirely of C/C composite material is machinable, and may have sufficient strength to operate in a molten metal environment. Advantageously, the design provides a central hub 1301 defining bore 1302, and surrounded by relatively large fluid receiving slits 1303 defined by slender vanes 1305. Vanes 1305 can be curved forward or backward as desired to increase rate flow or pressure.
    [0066] Returning now to Figure 14, the use of C/C composite material, in combination with graphite, is demonstrated. Particularly, a graphite cube 1401 defining an axis receiving bore 1402 is provided. A plurality of C/C composite vanes 1405 extend from hub 1401 and define fluid receiving slots 1403. Hub 1401 further includes a plurality of cutouts 1407 configured to receive an end 1409 of each vane 1405. 1409 can be cemented or powder bonded to the graphite hub 1401 within each cut 1407.
    [0067] Cast metal scrap, particularly aluminum, can be difficult to submerge, based on a variety of characteristics, such as the size of the scrap particles, and the presence of oil, or other organic material on its surface. More specifically, part size and organic content can strongly influence the buoyancy of the material, and adversely affect the scrap submersion system's ability to submerge the scrap. In this regard, refuse that is not submerged, and floats on top, will typically not melt, and may, in fact, burn. Consequently, rapid submersion of waste particles is an essential feature of any system.
    [0068] A variety of apparatus has been used in the melting compartment (specifically in the charge cavity), to facilitate the submersion of the scrap metal below the surface of the molten metal bath. A system is a mechanical system constructed primarily from a rotor that creates a flow of molten metal from the top surface. Examples of these devices are shown in U.S. Pat. 3,873,305; 3,997,336; 4,128,415; 4,930,986; and 5,310,412, the invention of which are incorporated herein by reference. The various components of this device can benefit from the construction of C/C composite material.
    [0069] Referring to Figure 15, a conveyor 1546 is disposed adjacent to the loading cavity 1518, forward from the front wall 1522. The scrap metal particles 1548 are conveyed by the conveyor 1546 for discharge into the loading cavity 1518. Mixer 1510 includes a 1550 drive and support motor. The 1550 drive and support motor are disposed above the load cavity 1518. A 1552 coupling protrudes from the underside of the 1550 drive and support motor. A vertically elongated shaft. oriented 1554 protrudes downwardly from the underside of coupling 1552. An impeller 1556 is rigidly secured to shaft 1554 at a location remote from coupling 1552. Impeller 1556 is disposed within cast metal 1542. Impeller 1556 or portions thereof and optionally shaft 1554, or portions thereof, may be produced from C/C composite material.
    [0070] As the invention has been described, it will be apparent to those skilled in the art that it can be varied in many ways, without departing from the intended spirit and scope of the invention, and any and all such modifications are intended to be included within the scope of the attached claims.
    [0071] The present exemplary invention has been described with reference to the preferred embodiments. Obviously, modifications and alterations will occur to others after reading and understanding the foregoing detailed description. The present invention is intended to be construed as including all such modifications and alterations, provided that they are within the scope of the appended claims, or equivalents thereto.
    权利要求:
    Claims (13)
    [0001]
    1. Molten metal processing apparatus, characterized in that it is selected from a pump, a degasser, a flow injector and a refuse submersion device, including at least one element selected from a shaft, impeller , bearing ring, pillar, pillar sleeve, injection tube, tube plug and riser in the case of a pump or at least one element selected from a shaft and impeller in the case of degasser, flow injector or refuse submersion device, wherein said element is comprised of C/C composite, said C/C composite being comprised of carbon fibers disposed in a carbon matrix and wherein said C/C composite element has been impregnated with an oxidation resistant chemical.
    [0002]
    2. Apparatus according to claim 1, characterized in that said element is further comprised of at least one of ceramic and graphite in combination with said composite C/C.
    [0003]
    3. Apparatus according to claim 2, characterized in that said element comprises an impeller.
    [0004]
    4. Apparatus according to claim 3, characterized in that at least one of a top plate, a bearing ring, and an impeller vane is comprised of said C/C composite.
    [0005]
    5. Apparatus according to claim 4, characterized in that said impeller comprises a graphite cube and at least one C/C composite vane.
    [0006]
    6. Apparatus according to claim 1, characterized in that said carbon fibers are in the form of a yarn or a fabric.
    [0007]
    7. Cast metal pump, degasser, flow injector, and/or refuse submersion device, characterized in that it comprises a motor, a shaft that engages the motor at a first end, and an impeller at a second end, wherein at least one component intended to be disposed below a molten metal surface is comprised of C/C composite.
    [0008]
    8. Cast metal pump, degasser, flow injector, and/or refuse submersion device, according to claim 7, characterized in that at least a portion of said shaft is comprised of C/C composite.
    [0009]
    9. Cast metal pump, degasser, flow injector, and/or refuse submersion device, according to claim 7, characterized in that said component comprises a bearing ring.
    [0010]
    10. Molten metal pump, degasser, flow injector, and/or refuse submersion device, according to claim 7, characterized in that said component comprises a pillar or a pole sleeve.
    [0011]
    11. Molten metal pump, degasser, flow injector, and/or refuse submersion device, according to claim 7, characterized in that said component comprises a gas injection tube and/or tube cap .
    [0012]
    12. Molten metal pump, degasser, flow injector, and/or refuse submersion device, according to claim 7, characterized in that said component comprises a riser tube.
    [0013]
    13. Molten metal pump, degasser, flow injector, and/or refuse submersion device, according to claim 7, characterized in that it further comprises a baffle plate comprised of C/C composite.
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    同族专利:
    公开号 | 公开日
    MX2017001866A|2017-06-08|
    US20170241713A1|2017-08-24|
    EP3180455A1|2017-06-21|
    CA2957718A1|2016-02-18|
    WO2016025676A1|2016-02-18|
    US10809005B2|2020-10-20|
    CN106795584A|2017-05-31|
    BR112017002708A2|2017-12-26|
    EP3180455B1|2020-01-15|
    EP3180455A4|2018-01-31|
    PL3180455T3|2020-07-13|
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    法律状态:
    2019-08-27| B06U| Preliminary requirement: requests with searches performed by other patent offices: procedure suspended [chapter 6.21 patent gazette]|
    2021-03-30| B09A| Decision: intention to grant [chapter 9.1 patent gazette]|
    2021-06-22| B16A| Patent or certificate of addition of invention granted|Free format text: PRAZO DE VALIDADE: 20 (VINTE) ANOS CONTADOS A PARTIR DE 13/08/2015, OBSERVADAS AS CONDICOES LEGAIS. |
    优先权:
    申请号 | 申请日 | 专利标题
    US201462037387P| true| 2014-08-14|2014-08-14|
    US62/037,387|2014-08-14|
    PCT/US2015/044987|WO2016025676A1|2014-08-14|2015-08-13|Advanced material for molten metal processing equipment|
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