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EP0259459B1 - Procedes et appareil atomiseur de poudre - Google Patents

Procedes et appareil atomiseur de poudre Download PDF

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Publication number
EP0259459B1
EP0259459B1 EP87901997A EP87901997A EP0259459B1 EP 0259459 B1 EP0259459 B1 EP 0259459B1 EP 87901997 A EP87901997 A EP 87901997A EP 87901997 A EP87901997 A EP 87901997A EP 0259459 B1 EP0259459 B1 EP 0259459B1
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EP
European Patent Office
Prior art keywords
substrate
impact
apparatus defined
powder
zone
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EP87901997A
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German (de)
English (en)
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EP0259459A4 (fr
EP0259459A1 (fr
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Richard F. Cheney
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F9/00—Making metallic powder or suspensions thereof
    • B22F9/02—Making metallic powder or suspensions thereof using physical processes
    • B22F9/06—Making metallic powder or suspensions thereof using physical processes starting from liquid material
    • B22F9/08—Making metallic powder or suspensions thereof using physical processes starting from liquid material by casting, e.g. through sieves or in water, by atomising or spraying
    • B22F9/082—Making metallic powder or suspensions thereof using physical processes starting from liquid material by casting, e.g. through sieves or in water, by atomising or spraying atomising using a fluid
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B9/00—General processes of refining or remelting of metals; Apparatus for electroslag or arc remelting of metals
    • C22B9/16—Remelting metals
    • C22B9/22—Remelting metals with heating by wave energy or particle radiation
    • C22B9/226—Remelting metals with heating by wave energy or particle radiation by electric discharge, e.g. plasma

Definitions

  • This invention relates to atomization techniques for producing ceramic powders and metal powders with extremely fine particle size, high density and optimum crystal and grain structure.
  • apparatus for atomizing of ceramics or metals comprising
  • the invention provides a method for atomizing granulated metal and ceramic feed material into fine particle size powder, comprising the steps of conveying an impact substrate comprising a thin film of polyetrafluoroethylene polymer edge-wise along a continuous path through an impact zone in an enclosed chamber, cleaning the exposed surface of the impact substrate, delivering granulated feed material entrained in a stream of gas through a plasma torch having its hot plasma jet directed toward the substrate in the impact zone, producing molten drops of feed material impacted and rebounding into molten droplets, delivering a stream of chilling gas through a quench gas chill zone adjacent to the impact zone, rapidly solidifying the molten droplets into fine particle size powder, and recovering the fine particle size powder from the enclosed chamber.
  • Atomized powders are produced with very fine particle diameters, high densities, and optimum internal structures. These are well adapted for flame coating, hot pressing, sintering and heat treatment at unexpectedly low temperature ranges, and they permit highly effective "alloying" of two or more different phases of fine ceramic powders or metals or combinations of metals with ceramics in the final hot pressed or sintered product.
  • Free-flowing powders for flame spray applications are disclosed in detail in my previous patents US-A-3,909,241, US-A-3,974,245 and US-A-3,881,911. Desired particle size ranges less than 60 micrometers (i.e., "microns") and preferably with 80 percent of the particles having sizes less then 30 micrometers have been considered optimal for flame spraying applications. Such powders have been produced by milling, screening and cyclone separation, with undersized particles being recycled into the original slurry and spray dried to leave only the desired particle size ranges for flame spraying use.
  • the rapid solidification of the molten droplets rebounding from the impact substrate produces the desired range of fine particle sizes coupled with unexpectedly valuable characteristics in the resulting fine particles of atomized metal or ceramic.
  • Virtually instantaneous chilling produces optimum chemical homogeneity of the solidified particles, and molecules of all different elements present are uniformly distributed in each solidified particle. Rapid chilling produces fine grain size, achieving strength and toughness in the resulting solid, enhanced resistance to chemical attack or corrosion, and in some cases, enhanced electrical properties.
  • Quick chilling minimizes the time available for growth of ordered crystal structures freezing outward from crystallization centers to meet each other along grain boundaries, producing either a single crystal, an amorphous glass-like particle with no internal grain boundaries, or a particle with desirably fine grain size.
  • a principal object of the present invention is to combine plasma torch melting with impact atomization and rapid chilling steps to achieve highly desired very fine particle powders of metals or ceramics.
  • Another object of the invention is to provide such methods and apparatus producing atomized powders having a majority of their particles substantially spheroidal in shape with desirably high densities and uniform, homogeneous structure.
  • a further object is to provide such methods and apparatus taking advantage of rapid chilling and solidification of molten droplets to produce atomized particles comprising a single crystal or having an amorphous, glass-like composition or having very fine grain size.
  • Still another object of the invention is to provide such methods and apparatus for producing such atomized powder particles with particle size ranges falling between one-tenth and twenty-five micrometers.
  • a still further object to the invention is to provide methods and apparatus for producing such atomized powders efficiently and economically.
  • FIGURES 1 and 3 A preferred embodiment of the apparatus employed in one form of the present invention is illustrated schematically in FIGURES 1 and 3, where all of the moving parts of the apparatus are shown positioned inside a double-walled, water-jacketed enclosure 10.
  • This heat insulating dual-walled enclosure is provided with a cooling water inlet conduit 11 and outlet conduit 12. It is also provided with two hinged gasketed doors 13 on opposite side walls which may be clamped shut or swung open to provide ready access to the interior of housing 10.
  • Each of the doors 13 is gasketed with suitable O-ring type gasket material 49 of heat resistant polymer, and each hinged door is also provided with internal cooling cavities connected by external flexible tubing 11A and 12A to the cooling water chambers inside the dual walls of housing 10.
  • Belt 14 passes over an upper roller 15 and forms a closed loop spanning the distance between roller 15 and a lower idler roller 16, which may be biased downward by springs or weights if desired to take up any slack in belt 14. This maintains slight tension in the belt, assuring that its sides, serving as the impact zones for the atomization step, are smooth and flat.
  • a support platen 17 Directly behind each smooth, falt side run of belt 14 is positioned a support platen 17. These support platens are shown positioned between the two straight runs of belt 14 on the interior of the endless belt loop, and anchored in these positions with their end edges secured to the interior walls of the housing 10. They are preferably hollow, with their interior chambers connected to the cooling water chambers inside the dual walls of housing 10.
  • FIGURE 1 Shown at the upper right and lower left of the internal chamber of housing 10 in FIGURE 1 are two plasma torches 18 mounted for reciprocating transverse movement parallel to the surface of the flat side runs of endless belt 14 with their output streams aimed at the exposed face of the belt.
  • Support platens 17 serve to counteract any belt deflection which would otherwise be produced by the impact stream from each plasma torch.
  • the plasma torches 18 are shown schematically in the drawings, and they incorporated the features shown in FIGURE 3, where a Dresser Industries' Plasmagun is shown in a cross-sectional side elevation view delineating its working parts.
  • the plasma gun or torch 18 is formed with a high voltage internal electric arc passing between its central cathode 19 and the surrounding ring-shaped nozzle or anode 20.
  • a continuous supply of high-pressure gas, typically helium, argon or nitrogen, is delivered through a gas inlet 21.
  • the electric arc produced between the cathode 19 and the anode 20 is thereby swept forward through the nozzle anode as a high temperature plasma jet 22, whose temperature normally exceeds 3,000 degrees Celsius.
  • a stream of pulverized feed stock powder ranging in average particle size from 50 to 500 micrometers is also supplied to the plasma torch 18 through a powder feed tube 23, delivering the powder feed stock directly into the ring-shaped anode 20 where it is swept from the plasma torch in the high temperature plasma jet 22. Pulverized particles of the powder are rapidly melted and the plasma jet thus becomes a high temperature, high velocity gas jet in which drops of molten feed stock powder are entrained.
  • a flexible supply conduit 25 inside housing 10 connects feed tube 23, cooling water conduits 24 and 27 and electrical power cables to each plasma torch 18.
  • each plasma jet 22 issuing from each plasma torch 18 is directed toward the smooth flat vertical run of substrate belt 14.
  • Each plasma torch 18 is mounted for reciprocating transverse movement, parallel to the flat vertical run face of belt 14, moving back and forth along a guide bar 28 and driven by such means as a reversible rack and pinion drive or an articulating pivoted counterweighted support linkage (not shown in the drawings).
  • Supply conduit 25 flexes freely to accommodate this reciprocating torch movement.
  • Aluminum foil with a laminated polytetrafluoroethylene "Teflon" surface layer has proved to be a highly effective impact substrate.
  • FIGURE 5 a greatly enlarged cross-sectional of this preferred substrate is illustrated.
  • the outermost layer of belt 14 is formed of a thin film 29 of Teflon FEP, approximately one mil thick.
  • This Teflon layer 29 is laminated directly to a slightly thicker layer of aluminum foil 31, two mils thick, for example.
  • the opposite face of foil layer 31 is bonded by a layer of adhesive cement 32 to a flexible temperature-resistant belt 33 of sheet metal or woven or non-woven fabric.
  • the adhesive layer 32 and the belt 33 are both flexible and the Teflon coating 29 and the very thin layer of aluminum foil 31 are also flexible.
  • the flexible impact film 29 of Teflon may be laminated directly to thicker flexible sheet aluminum backing performing the functions of foil 31 and metal backing 33 in FIGURE 5, and eliminating the need for adhesive 32.
  • This flexibility allows belt 14 to flex freely as it passes around the large diameter rollers 15 and 16. This assures that belt 14 will have an extended useful life despite the high temperatures employed in the atomization step of the process.
  • the reciprocating transverse movement of plasma torches 18 back and forth across the width of belt 14 produces a constantly shifting impact zone as the belt moves along its endless path between rollers 15 and 16.
  • the combination of belt advance and reciprocating torch movement produces a zigzag pattern of impact zones on the belt and minimizes local heating by the plasma jets 22 impacting upon the surface of Teflon-coated belt substrate 14.
  • Aluminum foil layer 31 aids in rapidly carrying away heat, further extending the useful life of belt 14.
  • the desired relative motion of substrate belt 14 and torch 18 can be produced by driving the belt rollers 15 and 16 in a combination of axial reciprocating and rotational movement so that all points on the peripheral surfaces of the rollers follow a sinusoidal path, producing sinusoidal movement of belt 14 relative to torch 18.
  • the two components of this belt movement relative to torch 18 should of course be out of phase to assure that every pass of belt 14 through each plasma torch impact zone exposes a fresh area of the belt to the hot plasma stream.
  • the impact substrate can also be formed as a greatly elongated web 46 unwound from a supply reel 47 past torch 18 and between plasma jet 22 and support paten 17, to be rewound on a takeup reel 48.
  • Liquid rinsing jet 45 and wipin squeegee 34 remove residual powder, and the elongated web 46 can be rewound on the supply reel like movie film and repeatedly reused in the same fashion, employing suitable drive motors on reels 47 and 48.
  • Residues of atomized powder are minimized on the Teflon surface of belt 14 because the smooth, low friction surface of the Teflon coating resists wetting of the substrate surface by the impacting molten drops of pulverized material.
  • Atomized powder particles which might happen to adhere to the Teflon surface of the substrate belt 14 would tend to interfere with subsequent impact atomization, on the next pass of the belt beneath the plasma torch 18. Therefore, such residues are preferably removed from the belt by the squeegee wiping action of a liquid-wetted wiping sponge 34 beneath which the belt 14 passes in sliding engagement, being sandwiched between sponge 34 and support platen 17, as shown in FIGURE 1.
  • any accumulated powder adhering to the Teflon surface 29 of belt 14 is wiped away by the sponge, and drained from the sponge by the impregnating liquid.
  • This liquid is preferably water in the case of ceramic powder atomization, and oil or an organic liquid such as hexane in the case of metal powder atomization.
  • Liquid squeezed from the sponge 34 by its compression against the passing belt 14 carries away any excess powder picked up from belt 14 and entrained in the excess liquid. Any moisture remaining on the surface of belt 14 is quickly evaporated by the high ambient temperatures inside housing 10 resulting from operation of the plasma torches 18.
  • one or more jets of pressurized liquid such as jets 45 shown in FIGURE 1, may be aimed at substrate 14.
  • a revolving cleaning brush 40 engaging the impact substrate 29, or a vacuum intake hood 50, or a vacuum cleaner type combination of brush 40 and vacuum hood 50 may be employed to remove accumulated atomized powder residues from the impact substrate.
  • a quench gas stream enters the interior of housing 10 at room temperature through one or more nozzles 36 aimed at the impact zone of each plasma jet.
  • the quench gas temperature may be reduced by its expansion through nozzles 36.
  • each of the molten liquid drops carried by the plasma jet impacts to form a ring-shaped droplet corona, taking advantage of the smoothness of belt 14 and the non-wetting, low-friction Teflon surface, with the resulting tiny droplets rapidly chilling due to the action of the quench gas stream delivered by quench gas nozzle means 36 aligned with the plasma torch and aimed at the impact stream's impact zone on belt 14.
  • the quench gas may be the same gas supplied through gas inlet 21 to create the plasma jet and carry the molten droplets to the impact zone.
  • Helium or hydrogen are preferred quench gases because of their high thermal conductivity, but argon and nitrogen are often used. This quick chilling, at a chill rate on the order of 100,000 or more degrees per second, produces such rapid solidification of the atomized droplets that they customarily exhibit homogeneous internal structure. These particles also exhibit very fine grain size, and may even be amorphous, i.e., without ordered atomic structure. Most of these atomized particles solidify with a spheroidal outer surface.
  • the resulting cloud of atomized fine powder particles filling the interior of housing 10 descends by gravity toward the bottom of the housing, passing with excess rinsing liquid through a hopper 37 to a powder collection sump 38.
  • the powder sump 38 is preferably detachable and interchangeable so that it may be removed and replaced by a fresh empty sump 38 in order to facilitate the powder recovery operation.
  • the sump 38 is provided with a sight glass 39 indicating the level of accumulated liquid collected therein.
  • the sump 38 is also provided with a detachable latch 41 securing it to the lower end of hopper 37 forming the bottom of housing 10.
  • latch 41 can be opened and the detachable sump 38 disconnected from the lower end of hopper 37.
  • a fresh, empty collection sump 38 is then moved into position and secured to hopper 37 by closing latch 41 and the accumulated contents of the filled sump 38 may be recovered by evaporating the liquid or centrifuging the powder slurry to separate the powder and liquid in the sump.
  • Wet filtration or vacuum drying or spray drying techniques may also be used to recover the atomized powder particles collected in the liquid of sump 38.
  • the impact substrate for atomization of molten powder drops carried in the plasma torch jet takes the form of a revolving metal or ceramic disk 42.
  • the cross-section of the disk 42 is generally similar to FIGURE 5, preferably with a thin layer 29 of Teflon FEP forming the exposed impact surface, with its underside bonded to a thicker layer of aluminum foil 31 secured by an adhesive 32 to a metal or ceramic turntable disk taking the place of the temperature resistant belt 33 illustrated in FIGURE 5.
  • the disk 42 is centrally supported on the end of a motor shaft 43 turned by motor 44 and thereby presenting a constantly changing zone of the substrate 29 in the impact path of plasma torch 18.
  • Quench gas delivered by the quench gas nozzles 36 aimed at the impact zone is supplied at a much lower temperature than the similar gas forming part of the plasma torch jet, and the introduction of a gas under pressure through both torch 18 and nozzle 36 produces a current tending to cause atomized powder particles, suspended in the atmosphere inside the housing surrounding the assembly shown in FIGURE 2, to flow through a vacuum intake powder collector 46 which may be provided with one or more fine mesh filter screens similar to dust collector bags, or may employ electrostatic precipitation techniques to attract the atomized powder particles to collection surfaces inside the powder collector 46.
  • the revolving brush 40, or the vacuum intake hood 50, or both employed together, as shown in FIGURE 2 are used to remove residual atomized powder from impact surface 29 before each pass through the plasma jet stream 22.
  • a wiper sponge 34 may be positioned for squeegee wiping contact with substrate 29, and provided with a liquid jet supply 47 through rinsing liquid jets 45, or a liquid manifold 48 positioned adjacent to the squeegee wiper 34.
  • the rotating disk embodiment illustrated in FIGURE 2 is customarilly used with ceramic powder atomization processes, in which the rinsing liquid is normally water, and the operating temperatures maintained by plasma torch 18 quickly evaporate liquid employed soon after the squeegee wiping action has been completed, assuring that the liquid leaves the working chamber as a vapor mixed with the flowing gas stream carrying atomized powder particles into powder collector 46. Since the wiping water is rapidly vaporized, there is no need for a liquid collection sump in the disk embodiment of FIGURE 2 corresponding to sump 38 shown in the embodiment of FIGURE 1, and the rotating disk atomization process is performed as a substantially dry operation.
  • the rinsing liquid is normally water
  • the operating temperatures maintained by plasma torch 18 quickly evaporate liquid employed soon after the squeegee wiping action has been completed, assuring that the liquid leaves the working chamber as a vapor mixed with the flowing gas stream carrying atomized powder particles into powder collector 46. Since the wiping water is rapidly vaporized, there is no need for a liquid collection sump in
  • FIGURE 2 While a single plasma torch is shown in FIGURE 2 and a pair of plasma torches as shown in FIGURE 1, three, four or more plasma torches may be employed if desired in a wider or longer housing 10, thus permitting scaling up of the volume of atomized powder produced while maintaining substantially the same operating characteristics for the process.
  • the squeegee sponges 34 are shown removed some distance away from the impact zone of the plasma torch jet on the substrate in FIGURE 1. However, for the best results it is often desirable to move the squeegee sponge 34 to a position closely adjacent and just upstream of the plasma jet impact zone on the moving substrate, to minimize any random deposit of airborne powder on the substrate before the plasma jet impact.
  • the belt drive motor 34 is preferably positioned outside housing 10 to assure that the motor and its bearings are isolated from the dusty environment inside the housing 10, and a dust seal around the motor shaft rotating the drive roller 15 is employed in the wall of housing 10. Dust-proof gaskets 49 on doors 13 retain the atomized powder particles inside housing 10.
  • Atomization runs on calcia-stabilized zirconia, 200/325 mesh (75/45 ⁇ m) "PP-42" produced by Bay State Abrasives of Westboro, Massachusetts were employed to compare the effects of changes in gun-to-substrate distance, plasma stream impact angle, and recycling the atomized material in a double atomization operation.
  • the starting powder appeared to be sharp irregular chips having dimensions ranging from 20 to 50 micrometers.
  • the resuling atomized powder particles are almost entirely spherical, with diameters ranging between 1 and 10 micrometers.
  • Teflon FEP film When Teflon FEP film was employed dry as the impact substrate, good results were achieved for several minutes, after which small patches of melted ceramic appeared on the substrate. This is believed to have been caused by fine powder electrostatically adhering to the substrate. On subsequent passes of the substrate through the plasma stream impact zone, such residual powder apparently melted and coalesced in situ .
  • Cleansing of the impact substrate before each pass through the impact zone to remove such residual powder particles can be achieved successfully by vacuum cleaning, or by a liquid rinse and squeegee wiping step. This removes any residual accumulations of electrostatically attracted powder, and facilitates continuous powder atomization over long production runs.
  • Table 1 shows the particle sizes observed after a series of seven powder production runs, Sample 14-1 was atomized using the dry Teflon FEP substrate described above. The remaining runs were all made on a Teflon FEP substrate which was liquid rinsed and squeegee wiped. For runs 15-3, 14-2 and 15-2, the axis of the plasma stream was substantially normal to the substrate surface, and the distance was reduced successively from 5 inches (12.7 cms) to 4 inches (10 cms) to 3 inches (7.62 cms), producing successively finer average particle sizes as Table 1 shows.
  • run 14-3 the plasma stream axis was inclined at 45 degrees to the surface of the impact substrate, producing a wider range of particle sizes and a slight increase in average particle diameter.
  • FIGURES 6A, 6B and 6C show the shape and size distribution of zirconia powder atomized by plasma torch jet impact against a dry Teflon FEP film substrate utilizing the equipment illustrated in the embodiment of FIGURE 2. Virtually all these atomized powder particles are spherical and their size ranges are shown in the particle size distribution figures summarized in Table 1.
  • Particle sizes for the atomized zirconia powder particles are shown in the particle size distribution diagrams annexed as the diagrams of FIGURES 7-11. As clearly illustrated in these size distribution curves, 50% of the atomized powder particles are customarily smaller than five micrometers in diameter and may be smaller than one, two or three micrometers in diameter. The great majority of atomized powder particles are less than ten micrometers in diameter.
  • Table 2 summarizes the excellent density figures for these powders after consolidation by hot pressing, i.e., the application of heat and pressure to the powders. This confirms that these powders are ideal for hot pressing purposes. It is conjectured that these good hot pressing results are promoted by the very fine and stable particle size, sphericity, and extremely favorable powder densities.
  • Agglomerated molybdenum powder, -200 + 325 mesh (75 to 45 ⁇ m) was delivered at the rate of 10 lbs. (4.53 Kg) per hour to the plasma gun shown in FIGURE 1, spaced 4 inches (10 cms) from the rotating disk Teflon FEP substrate with the plasma stream axis normal to the disk surface. Average current of 600 amp. was drawn at voltages ranging between 25 and 30 volts. The resulting atomized powder comprised almost entirely spherical particles having diameters under 10 micrometers.

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  • Mechanical Engineering (AREA)
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Claims (26)

1. Appareil pour l'atomisation de céramiques ou de métaux, comprenant
A. un carter thermo-résistant entourant une chambre d'impact et ayant des moyens à portes d'accès à garnitures formés dans celle-ci,
B. un moyen de refroidissement installé dans le carter et les moyens à porte,
C. un moyen d'avancement de substrat juxtaposé à une zone d'impact dans la chambre et supporté par le carter,
D. un substrat d'impact comprenant un mince film de polymère de polytétrafluoréthylène monté sur le moyen d'avancement pour avancer ledit substrat d'impact d'un mouvement perpendiculaire à travers la zone d'impact,
E. un moyen à tuyère à gaz de refroidissement supporté par le carter et pointé pour fournir du gaz de refroidissement sous pression à une zone de refroidissement à gaz de trempe adjacente à la zone d'impact,
F. une torche à plasma supportée dans une chambre, reliée à une source d'énergie électrique et à une source d'alimentation sous pression de gaz entraînant du matériel d'alimentation pulvérisé devant être atomisé, pointée pour fournir le jet de plasma chaud contenant des gouttes fondues de matériel d'alimentation pour s'écraser sur le substrat avançant dans la zone d'impact, produisant des gouttelettes atomisées rebondissantes qui sont refroidies et solidifiées pour produire des particules microatomisées dans la zone de refroidissement à gaz de trempe par le gaz de refroidissement,
G. un moyen de nettoyage de substrat supporté dans la chambre juxtaposée au substrat avançant près de la zone d'impact.
H. un moyen de récupération de poudre raccordé pour recevoir et recueillir la poudre produite dans la zone d'impact.
2. Appareil défini à la revendication 1, dans lequel le substrat d'impact est le "téflon FEP".
3. Appareil défini à la revendication 2, dans lequel le substrat d'impact est le "téflon PFA".
4. Appareil défini à la revendication 1, dans lequel le mince film de polymère est renforcé par une couche plus épaisse de feuille métallique.
5. Appareil défini à la revendication 4, dans lequel la feuille métallique est en aluminium.
6. Appareil défini à la revendication 1, dans lequel le film de polymère est monté sur une bande de substrat flexible allongée pour effectuer un mouvement avançant perpendiculaire poussé par le moyen d'avancement du substrat.
7. Appareil défini à la revendication 6, dans lequel la bande de substrat flexible allongée est sous forme d'une bande sans fin supportée en entraînement par au moins un rouleau-bande entraîné comprenant le moyen d'avance du substrat.
8. Appareil défini à la revendication 1, dans lequel le mince film de substrat de polymère est monté sur la face d'un disque monté à rotation dans la zone d'impact comprenant le moyen d'avance du substrat.
9. Appareil défini à la revendication 1, dans lequel le moyen d'avance du substrat est entraîné par un moteur électrique monté à l'extérieur du carter et dont l'arbre s'étend à travers le carter dans la chambre d'impact et est relié pour entraîner le moyen d'avance du substrat.
10. Appareil défini à la revendication 1, dans lequel la torche à plasma et le moyen d'avance du substrat sont reliés pour effectuer un mouvement traversant relatif, opérant un mouvement de translation dans la zone d'impact à travers le substrat d'impact en un trajet sinueux.
11. Appareil défini à la revendication 10, dans lequel la torche à plasma est montée pour effectuer un mouvement de va-et-vient dans une direction transversale par rapport au mouvement avançant du substrat d'impact.
12. Appareil défini à la revendication 10, dans lequel la torche à plasma est pourvue de tuyaux d'alimentation en poudre et en gaz, d'un tuyau d'entrée d'eau de refroidissement, d'un tuyau de sortie d'eau de refroidissement, et de conducteurs d'énergie électrique, et en outre comprenant un tuyau flexible d'alimentation enfermant lesdits tuyaux d'alimentation, de sortie et d'entrée et les conducteurs d'énergie et les reliant à travers une partie de paroi du carter à la torche à plasma à va-et-vient.
13. Appareil défini à la revendication 1, dans lequel le moyen de nettoyage de substrat comprend un moyen à jet de rinçage liquide.
14. Appareil défini à la revendication 1, dans lequel le moyen de nettoyage de substrat comprend un moyen à raclette essuyante en caoutchouc mouillée de liquide.
15. Appareil défini à la revendication 1, dans lequel le moyen de nettoyage de substrat comprend une calotte aspirante positionnée près du substrat d'impact.
16. Appareil défini à la revendication 1, dans lequel le moyen de nettoyage de substrat comprend une brosse montée pour effectuer un mouvement relatif en contact de brossage avec le substrat d'impact.
17. Appareil défini à la revendication 1, dans lequel le moyen de récupération de poudre comprend un bassin de réception rattaché de manière détachable au carter près d'une extrémité inférieure de celui-ci.
18. Appareil défini à la revendication 17, dans lequel le bassin de réception comprend un voyant extérieur en verre à travers lequel on peut observer le niveau de liquide accumulé dans le bassin.
19. Appareil défini à la revendication 1, dans lequel le moyen de récupération de poudre comprend un ensemble à crible à filtre d'entrée aspirant.
20. Procédé pour l'atomisation en une poudre à fine granulométrie de matériel d'alimentation en céramique et métal granulé, comprenant les étapes de
   transporter un substrat d'impact comprenant un mince film de polymère de polytétrafluoréthylène perpendiculairement le long d'un trajet continu à travers une zone d'impact dans une chambre fermée,
   nettoyer la surface exposée du substrat d'impact,
   livrer le matériel d'alimentation granulé entraîné dans un flot de gaz à travers une torche à plasma dont le jet de plasma chaud est dirigé vers le substrat dans la zone d'impact, produisant des gouttes fondues de matériel d'alimentation écrasées rebondissant en des gouttelettes fondues,
   livrant un flot de gaz de refroidissement à travers une zone de refroidissement à gaz de trempe adjacente à la zone d'impact, solidifiant rapidement les gouttelettes fondues en une poudre à fine granulométrie, et
   récupérer la poudre à fine granulométrie provenant de la chambre fermée.
21. Procédé défini à la revendication 20, dans lequel le trajet le long duquel le substrat d'impact est transporté à travers la zone d'impact, est un trajet sans fin le long duquel le substrat est recyclé de manière continue.
22. Procédé défini à la revendication 20, dans lequel le gaz de refroidissement et le jet de plasma chaud sont livrés simultanément et continuellement à la zone d'impact.
23. Procédé défini à la revendication 20, dans lequel le nettoyage du substrat est effectué en livrant du liquide de rinçage sous pression pour laver le substrat d'impact.
24. Procédé défini à la revendication 20, dans lequel le nettoyage du substrat est effectué en essuyant le substrat d'impact approchant la zone d'impact avec une opération d'essuyage au moyen d'une raclette en caoutchouc mouillée de liquide.
25. Procédé défini à la revendication 20, dans lequel le jet de plasma chaud est déplacé pour lui faire traverser en un mouvement de va-et-vient la zone d'impact dans une direction transversale par rapport au mouvement perpendiculaire du substrat d'impact.
26. Procédé défini à la revendication 20, dans lequel l'opération de récupération de la poudre est effectuée en un trajet d'écoulement aspirant à vide le long duquel l'atmosphère provenant de l'intérieur de la chambre fermée est retirée à travers un crible à filtre à fines mailles arrêtant la poudre de fine granulométrie.
EP87901997A 1986-03-13 1987-03-09 Procedes et appareil atomiseur de poudre Expired - Lifetime EP0259459B1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT87901997T ATE70758T1 (de) 1986-03-13 1987-03-09 Pulverspruehverfahren und vorrichtung.

Applications Claiming Priority (2)

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US83926486A 1986-03-13 1986-03-13
US839264 1986-03-13

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EP0259459A1 EP0259459A1 (fr) 1988-03-16
EP0259459A4 EP0259459A4 (fr) 1988-06-23
EP0259459B1 true EP0259459B1 (fr) 1991-12-27

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EP (1) EP0259459B1 (fr)
JP (1) JPS63502839A (fr)
AT (1) ATE70758T1 (fr)
DE (1) DE3775499D1 (fr)
WO (1) WO1987005548A1 (fr)

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US7966970B2 (en) 2005-07-19 2011-06-28 M Management-Tex, Llc Dairy inflation
US7997439B2 (en) 2003-06-06 2011-08-16 Jamak Fabrication-Tex, Llc Flexible bakeware having a multi-piece carrier system

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JPH02229561A (ja) * 1989-03-01 1990-09-12 Nordson Kk 液体又は溶融体の粒子の生成方法とその装置
FR2679473B1 (fr) * 1991-07-25 1994-01-21 Aubert Duval Procede et dispositif de production de poudres et notamment de poudres metalliques par atomisation.
EP4527524A3 (fr) * 2015-07-17 2025-06-11 AP&C Advanced Powders And Coatings Inc. Procédés de fabrication de poudre métallique par atomisation au plasma et systèmes s'y rapportant
CN108367361A (zh) 2015-10-29 2018-08-03 Ap&C高端粉末涂料公司 金属粉末雾化制造方法
AU2017249439B2 (en) 2016-04-11 2022-10-20 Ap&C Advanced Powders & Coatings Inc. Reactive metal powders in-flight heat treatment processes
CN110976891A (zh) * 2019-12-22 2020-04-10 安徽哈特三维科技有限公司 一种真空感应熔炼气雾化制粉的辅助输料装置
CN112682994B (zh) * 2021-01-05 2022-06-17 长沙有色冶金设计研究院有限公司 粉体物料骤冷装置
CN113318662A (zh) * 2021-07-05 2021-08-31 浙江钦堂钙业有限公司 碳酸钙粉体活化处理装置

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Cited By (3)

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Publication number Priority date Publication date Assignee Title
US7997439B2 (en) 2003-06-06 2011-08-16 Jamak Fabrication-Tex, Llc Flexible bakeware having a multi-piece carrier system
US7966970B2 (en) 2005-07-19 2011-06-28 M Management-Tex, Llc Dairy inflation
US8402921B2 (en) 2005-07-19 2013-03-26 M Management-Tex, Llc Dairy inflation

Also Published As

Publication number Publication date
EP0259459A4 (fr) 1988-06-23
ATE70758T1 (de) 1992-01-15
EP0259459A1 (fr) 1988-03-16
DE3775499D1 (de) 1992-02-06
JPS63502839A (ja) 1988-10-20
WO1987005548A1 (fr) 1987-09-24

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