• 专利附录
  • 专利说明
  • 权利要求
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    • 专利摘要:
    device for melting a material without a crucible, method for producing powder by melting a material without a crucible, e, powder. the invention relates to a device (1) for melting a material without a crucible, and for spraying the molten material for the production of powder comprising: a spray nozzle (5); an induction coil (4) with turns (4a-d), which become narrower in the direction of the spray nozzle (5) at least in sections; and a material bar (3) inserted, at least partially in the induction coil (4). the induction coil (4) is equipped to melt the material from the material bar (3), to produce a melt flow (16). the induction coil (4) and the spray nozzle (5) are arranged in such a way that the melt flow (16) can be introduced or is introduced into the spray nozzle (5) for spraying the melt flow ( 16) by means of a spray gas (19), which can be introduced into the spray nozzle (5) through a first opening (20) of the spray nozzle (5). the device is characterized by the fact that the spray nozzle (5) is executed in such a way that the spray gas (19) can be introduced or is introduced into the spray nozzle (5) only through the first opening (20) of the spray nozzle (5); that the spray nozzle (5) is equipped to accelerate the spray gas (19) in a direction parallel to the melt flow (16) at least to the speed of sound of the spray gas (19); and that the material bar (3) and the induction coil (4) are arranged such that before the melt flow (16) enters the spray nozzle (5), the melt flow (16) can be heated or is heated inductively by the induction coil (4). moreover, the invention relates to a corresponding method for melting a material without a crucible and for spraying the molten material for the production of powder.
    公开号:BR112016014264B1
    申请号:R112016014264-0
    申请日:2014-12-19
    公开日:2021-04-13
    发明作者:Lüder Gerking；Christian Gerking；Martin Stobik；Rico Heinz
    申请人:Nanoval Gmbh & Co. Kg；
    IPC主号:
    专利说明:

    [001] The invention relates to a device and a method for melting a material without a crucible, and for spraying the molten material for the production of powder, in particular, for the production of metal powder or ceramic powder .
    [002] In many areas of the technique, metal powders are used. Thus, metal powders are produced in the powder injection molding process (MIM) or also in the generative process also called additive process, such as laser sintering / laser fusion and electron beam fusion, and can be fused to form structures complex three-dimensional. Metal powders with grain sizes in the micrometer range are often required. In this case, for many application cases it is of great importance that the grain size of the metal powder does not exceed a maximum grain size, or that the fluctuation range of a statistical distribution of the grain size of the produced powder is as small as possible such that the grain size therefore deviates as little as possible from a desired grain size.
    [003] From German patent document DE1034060684 it is known to melt metal in a crucible, and spray it through a Laval nozzle to form metal dust. In this case, it is of decisive importance to thermally shield the melting nozzle, with which the molten metal in the crucible is introduced into the nozzle, in relation to the spray gas, since otherwise the melt cools very sharply, which worsens considerably the quality of the powder produced (grain shape, grain size, grain size distribution range), or makes spraying impossible. Therefore, in DE1034060684 a corresponding shield was suggested. A challenge was to perform the shielding in such a way that it does not adversely affect the flow profile of the spray gas before entering the nozzle, as this flow profile also has a considerable influence on the quality of the powder produced.
    [004] A disadvantage of the device described in document DE1034060684 is the fact that in the crucible no materials can be melted and sprayed, which react chemically with the crucible's coating, and as a result of this reaction are contaminated. This problem arises, for example, in the case of fusion with a titanium crucible. For this reason, already in document DE4102101A1, a device for melting metal without a crucible was suggested. In this case, a metal bar is melted by means of an induction coil and then, in the same way, it is sprayed through a spray nozzle. In the case of the device according to DE4102101A1, however, the problem arises to an even greater extent than in the case of the device according to DE1034060684, in such a way that the melt flow produced during the melting of the bar is cooled enough by the spray gas.
    [005] In order to get around this problem, in the device according to document DE4102101A1 a totally different type of spray is suggested. According to it, the nozzle has a first opening, through which the melt flow is introduced into the nozzle. In turn, the spray gas is introduced into the nozzle through a lateral opening of the nozzle, different from the first opening, therefore, in a direction perpendicular to the flow direction of the melt flow through the nozzle. In the nozzle the spraying gas strikes the melt flow perpendicularly and breaks the melt flow, in such a way that drops are formed, which then freeze to form powder. In essence, the same type of spray is also described in European patent document EP176553681. Through the lateral introduction of the spray gas into the nozzle, the cooling of the melt flow can be partially prevented before entering the nozzle.
    [006] However, it has been shown that with the type of spray suggested in documents DE4102101A1 and EP176553681, often only powder with a relatively large grain size distribution range can be produced. A desired grain size, therefore, can be adjusted in certain circumstances only with little accuracy, in such a way that eventually a lot of scrap occurs. In this way, production costs can be increased.
    [007] Therefore, the present invention has the task of creating a device and a method, with which the widest possible variety of materials can be sprayed, being that a grain size and the grain size distribution of the powder produced must be able to be adjusted as accurately as possible.
    [008] This task is solved by a device and by a method according to the independent claims. Special forms of execution are described in the subordinate claims.
    [009] It is therefore suggested a device for melting a material without a crucible, and for spraying the molten material for the production of powder comprising:
    [0010] a spray nozzle;
    [0011] an induction coil with coils, which become narrower in the direction of the spray nozzle at least in sections; and
    [0012] a material bar inserted, at least partially in the induction coil;
    [0013] being that, the induction coil is equipped to melt the material of the material bar, for the production of a melt flow; and
    [0014] whereby, the induction coil and the spray nozzle are arranged in such a way that the melt flow can be introduced or is introduced into the spray nozzle for the spraying of the melt flow by means of a spray gas , which can be inserted into the spray nozzle through a first opening of the spray nozzle.
    [0015] The spray nozzle is made in such a way that the spray gas can be introduced or is introduced into the spray nozzle only through the first opening of the spray nozzle. In addition, the spray nozzle is equipped to accelerate the spray gas in a direction parallel to the melt flow at least, to the speed of the spray gas sound. In addition, the material bar and the induction coil are arranged such that before the melt flow enters the spray nozzle, therefore, typically in an area between one end of the material bar facing the spray nozzle and the spray nozzle, the melt flow can be heated or is heated inductively by the induction coil. Preferably, in particular, at its end facing the spray nozzle, the induction coil is executed in such a way that there the melt flow can be heated or is heated inductively where it flows freely, in such a way that it does not cool . For example, it is heated in such a way that it maintains the minimum temperature required for the spraying process. In the area in which the melt flow flows freely, therefore, normally between the end of the material bar, facing the spray nozzle, and the spray nozzle, the melt flow is exposed most of the spray gas, which it surrounds it and flows around on all sides.
    [0016] In addition, a method for the production of powder is suggested by melting a material without a crucible and by spraying the molten material comprising the steps:
    [0017] At least partial introduction of a material bar in an induction coil that is reduced conically at least in sections;
    [0018] Intake of the induction coil with an alternating voltage, for the melting of the material bar and for the production of a melting flow;
    [0019] Introduction of the melt flow in a spray nozzle through a first opening of the spray nozzle; and
    [0020] Introducing the spray gas into the spray nozzle and spraying the melt flow by means of the spray gas;
    [0021] Since, the spray gas is introduced into the spray nozzle only through the first opening of the spray nozzle;
    [0022] whereby the spray gas to be introduced and / or introduced into the spray nozzle through the first opening, in a direction parallel to a flow direction of the melting flow, is preferably accelerated, parallel to a direction of flow of the melt flow through the spray nozzle, at least up to the speed of sound of the spray gas, such that the melt flow splits and even bursts, and powder with a grain size in the range of micrometers and / or in the submicrometer range; and
    [0023] and, before the fusion jet enters the spray nozzle, the fusion jet is heated inductively by the induction coil.
    [0024] In the following, for the sake of simplicity, the spray nozzle, induction coil and material bar will be referred to simply as nozzle, coil and bar. Therefore, all spray gas or in essence, all spray gas determined for spraying the melt is introduced into the nozzle through the same first nozzle opening as the melt flow. The first opening of the nozzle is usually facing the coil and the bar. Through a second opening of the nozzle then, normally the spray gas and the sprayed melt flow totally or partially exits the nozzle again. Preferably, the nozzle therefore has, next to the first and second opening, no other opening, in particular, any lateral openings for the introduction of gas perpendicular or in essence, perpendicular to the axis of the nozzle, as is the case, for example , of the devices according to documents DE4102101A1 and EP176553681.
    [0025] It has been shown that with the device suggested here and with the method suggested here a wide variety of different materials without a crucible can be sprayed with very good results for the production of dust. Therefore, powders with a narrow range of grain diameter distribution can be produced, and the desired grain diameter and diameter distribution can be well adjusted by a number of process parameters and / or device parameters. An essential advantage is that materials can also be sprayed, which cannot be melted in a crucible, because the material to be sprayed melts at higher temperatures than the crucible material, or reacts with it and is thus contaminated, by heating the melt flow through the coil, cooling or freezing of the melt flow prior to spraying is effectively prevented.
    [0026] Normally the material bar, the induction coil and the spray nozzle are aligned along a vertical direction, along which the force of gravity acts. The melt flow then falls, therefore, under the influence of the force of gravity, or at least also under the influence of the force of gravity through the spray nozzle. The bar, coil and nozzle may have a cylindrical symmetry or approximately cylindrical symmetry, respectively, with the bar, coil and nozzle then typically being arranged in such a way that their axes of symmetry are arranged on the same line. But in principle the bar, the coil and the nozzle can have arbitrarily shaped cross sections. For example, the nozzle may have a slit-shaped, rectangular, oval or round cross section. Likewise, the bar can also have a round, oval or polygonal cross section. The bar can also be made in the form of a plate. The shapes of the coil and the nozzle must then be adapted to match the shape of the bar plate.
    [0027] The coil normally has at least three turns, preferably between three and six turns. Preferably, the dimensions of the coil and the bar should be adapted to each other, such that for the fusion of the bar, an efficient transfer of energy from the coil to the bar can occur. Preferably, the coil is supplied with an alternating voltage f, which is approximately between 50 kHz and 200 kHz, preferably between 100 kHz and 150 kHz. For the fusion of the bar, the coil is normally operated with a power between 10 and 150 kW, according to the material of the bar.
    [0028] A surface of the nozzle cross section can decrease continuously or at least in sections, along the nozzle axis in the flow direction of the melt flow through the nozzle. For example, the surface of the nozzle cross section may decrease linearly or stronger than linearly along the axis of the nozzle in the direction of flow. The nozzle can be used, for example, as a Laval nozzle.
    [0029] The Laval nozzle may then have a contour that ends radially away from the axis of the Laval nozzle, such that the flow from the state of the resting environment to the accelerated gas is conducted through the Laval nozzle at a great distance in relation to the axis of the Laval nozzle. A diameter of the contour of the Laval nozzle, for example, in the area of the first opening of the nozzle can be approximately 0.5 times to three times the diameter of the coil, preferably 0.8 times to double. In the case of the mentioned coil diameter, it may be the diameter of the coil at the end of the coil away from the nozzle or at the end of the coil facing the nozzle.
    [0030] A variant is the so-called two-stage nozzle, in which two distinctly curved nozzle contours pass through each other in such a way that a ring-shaped corner appears in a plane perpendicular to the nozzle axis.
    [0031] The device typically features a lifting and lowering device to stop, raise and lower the material bar. In order to keep the position of the end of the bar towards the nozzle approximately constant, in which the bar is preferentially fused, during the process, the bar is guided, for example, continuously to the coil. In order to make the melting of the bar as uniform as possible, the lifting and lowering device is preferably additionally equipped to rotate the bar around the axis of the bar, for example, with a number of revolutions of at least 1 min- 1.
    [0032] If the material bar is discussed below, the material bar is considered, as it is solid and has not yet been cast. The melt or melt flow should be observed not as part of the material bar, in particular, in relation to the dimensions of distance between the bar and other components of the device.
    [0033] The material, from which the material bar is formed can comprise metal or ceramic. The material of the material bar from which the powder is produced may contain, for example, one of the following metals or an alloy of one or more of the following metals: titanium, aluminum, iron, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, rhenium, nickel, cobalt.
    [0034] With the suggested method, powder with a mean grain diameter related to the mass of less than 50 μm can be produced. The average grain diameter related to the dough can also be less than 10 μm or less than 1 μm.
    [0035] An amplitude of the grain size distribution of the produced powder can be characterized by the diameters d84 and d50. These diameters are defined as follows: 84 percent of the powder (weight percentage) has a grain diameter, which is less than d84 and that 50 percent of the powder (weight percentage) has a grain diameter, which is less than d50. With the suggested process, for example, powders may be produced in which it is worth: d84 / d50 ^ 2.8, preferably d84 / d50 ^ 2.3, particularly preferred d84 / d50 ^ 1.8.
    [0036] In order to obtain a particularly narrow grain size distribution, a minimum internal diameter dmin of the spray nozzle may be less than 7 mm, preferably less than 5 mm, particularly preferably less than 3 mm. In this case, the internal diameter must be defined by the nozzle, respectively perpendicular to the nozzle axis or perpendicular to the flow direction of the melt flow. Typically the minimum internal diameter appears at the position along the nozzle axis, in which the nozzle or nozzle tube has the minimum cross-sectional surface. Preferably, the internal diameter is defined along a straight line, which passes through the central point of the cross section.
    [0037] For the characterization of the device, a plane can be used, which cuts the nozzle axis or the flow direction of the melting flow perpendicularly through the nozzle, and in fact in that position along the nozzle axis or along the direction of flow in which the cross-sectional surface of the spray nozzle, in particular, therefore, the cross-sectional surface of the channel formed by the nozzle is minimal. For the sake of simplicity, hereinafter this plane will also be designated as the plane of the narrowest cross-section.
    [0038] Constructive measures can be taken in order to feed the melt close enough to the nozzle, in such a way that it can be picked up particularly well by the gas flow of the spray gas as described. Due to the necessary proximity of the coil in relation to the material bar precisely in the lowest area, where complete melting must occur, so that no rest of the bar remains asymmetrically superfluous or eccentrically where, therefore, a cooling and freezing of the material must be avoided unconditionally. melt flow on the way to the nozzle due to cooling through the generally cold gas flow, which catches and accelerates the melt flow for energetic reasons, results in a distance from the maximum preferred melting area of the nozzle. In this preferred path, even the narrowest cross section of the nozzle there is an increase in pressure inside the fusion jet, due to the buoyant stresses between the faster gas flow and it, while in other methods a cold gas is in relatively short contact with the merger, since it has no common direction with this merger either before or after that contact - at most stochastic, therefore, in occasional parts and, furthermore, also does not need a long contact time , because the gas already has high kinetic energy and, therefore, no longest common path section is covered with possible and undesired cooling.
    [0039] Therefore, the material bar and the spray nozzle can be arranged in such a way that a minimum distance L between the material bar and the plane of the narrowest cross-section is less than 7 ^ dmin, less than 6 ^ dmin, less than 5 • dmin or less than 4 ^ dmin. For example, this way it can be reacted against too strong a cooling of the melt flow before spraying. Typically at one end of the bar, which faces the nozzle, the bar is approximately cone-shaped. So L is usually the distance from the tip of the cone to the plane of the narrowest cross-section.
    [0040] Preferably, the spray nozzle and the induction coil are made as separate components. So the induction coil, therefore, in particular, is not integrated into the nozzle. In the direction of flow in this form of execution the coil is usually arranged before or above the nozzle. The device with this is particularly flexible. For example, the coil can be easily changed or adjusted in relation to the nozzle. In addition, it can be effectively prevented that the nozzle is overheated or even fused by the coil.
    [0041] In order to avoid too strong cooling or even a freezing of the melt flow before spraying, and to be able to support the flow of the melt flow, the induction coil and the spray nozzle can be arranged in such a way that a minimum amin distance between the induction coil and the plane of the narrowest cross section is less than 4 ^ dmin, less than 3 ^ dmin, or less than 2 • dmin. Preferably, in this case, the amin distance is defined in a direction parallel to the nozzle axis or parallel to the flow direction of the melt flow. The coil can also reach directly to the nozzle, or be in contact with the nozzle. In this case, the nozzle should be formed of a non-conductive material.
    [0042] In order to eliminate an electromagnetic coupling from the nozzle to the coil, and to avoid inductive heating of the nozzle by the coil as much as possible, the nozzle can be formed of a material, which is either a very good or very bad electrical conductor. If the nozzle material is a very good conductor, then ohmic losses hardly occur, which are dissipated in the nozzle in the form of heat. If, on the contrary, the nozzle material is a very bad conductor, then no or almost no turbulence flow is induced in the nozzle, which likewise does not lead or hardly leads to ohmic losses. Therefore, for a specific electrical resistance of the nozzle material, p <0.02-10-6 Qm or p ^ 10-2 Qm is preferably used.
    [0043] Another special form of execution of the device is characterized by a high pressure chamber, a spray chamber that is in fluid connection with the high pressure chamber, through the spray nozzle, first means of regulating pressure for the introduction of the spray gas in the high pressure chamber, and for the regulation of a first pressure of the gas p1 in the high pressure chamber, as well as second means of pressure regulation for the regulation of a second pressure of the gas p2 in the pressure chamber. spraying, the first and second pressure regulating means being equipped to adjust the pressures p1 and p2 for the acceleration of the spraying gas in a direction parallel to the flow direction of the fusion flow, in such a way that it is worth: p1 / p2> 1.8 and p1> 10 bar. The first pressure of gas p1, therefore, is greater than the second pressure of gas p2.
    [0044] Typically, the second pressure of gas p2 in the spray chamber makes up approximately 1 bar. By adjusting the gas pressures p1 and p2, the acceleration of the spray gas before the nozzle, inside the nozzle and behind the nozzle can be influenced and regulated. Thus, also the thrust stresses transmitted to the melt flow and possibly the degree of centering and dilation of the melt flow can be influenced, in particular, even before the melt flow enters the nozzle and / or before spraying of the melt flow. The first and second pressure regulating means may comprise, for example, one or more pumps, conductors, nozzles, valves, a compressor and / or a high pressure gas tank respectively.
    [0045] It is particularly advantageous, first of all, to heat, in the most effective and uniform way possible, at its end facing the nozzle, therefore, typically at the lower end, since, in this case, the fusion of the bar occurs. Also the end of the material bar, facing the nozzle should be disposed within the coil, therefore, preferably not in the direction of the flow through which the end of the coil facing the nozzle projects outwards.
    [0046] In addition, it is advantageous if at least one of the turns of the inductive coil, which is arranged in the area of the end of the material bar, facing the nozzle, for the production of an electromagnetic magnetic field in this area, passes the most symmetrical as possible with respect to the bar axis, at least by sections, perpendicular to the bar axis. Preferably, at least the last coil loop facing the nozzle passes, at least in sections, perpendicular to the axis of the bar, or to the direction of the melt flow. For example, at least, the last loop can involve totally or almost totally the axis of the bar or an imaginary extension of the axis of the bar in a plane perpendicular or almost perpendicular to the axis of the bar.
    [0047] In this way, at least one of the turns, in particular, at least the last loop can be performed as an annular conductor electrically interrupted at a point, preferably as an almost closed annular conductor. The interruption can be carried out as an air gap or through an insulating material. The term ring conductor should encompass not only a ring-shaped conductor. On the contrary, he must understand an infinite number of forms. Decisive is the fact that the annular conductor, along most of its length, passes, in essence, in a plane and forms an almost closed conductor loop. For example, the ring conductor can pass at least 50 percent, at least 70 percent, or at least 90 percent in a perpendicular plane, or in essence, perpendicular to the bar axis or perpendicular or, in essence, perpendicular to the flow direction of the melt flow. The ring conductor may involve the bar axis or an imaginary extension of the bar axis by at least 180 degrees, at least 225 degrees, at least 270 degrees, at least 315 degrees or almost 360 degrees perpendicular or almost perpendicular to the bar axis. The ring conductor can be largely circular, oval, rectangular or polygonal. It may, for example, have a horseshoe shape. The ring conductor does not have to be symmetrical. Preferably, however, the annular conductor is arranged with rotation symmetry or almost with symmetry of rotation in relation to the axis of the bar or to the flow direction of the melt flow. In this way, the ring conductor can be executed, for example, in an approximately circular manner.
    [0048] In the case of a special design, the coil may have at least two ring conductors of the type described. The at least two ring conductors can be made of the same material as the conductor, for example, copper. The at least two ring conductors can be connected electrically in parallel. In order for the ring conductors connected in parallel to have, respectively, an approximately equal electrical resistance and / or to produce the most homogeneous field distribution possible along the axis of the bar, the ring conductors may have cross sections executed with different extension and / or have different intervals from each other along the axis of the bar. In the case of the cross section, it is the cross section of the conductive tube or the conductive wire of the ring conductor. For example, a first annular conductor and a second annular conductor can be connected in parallel, the first annular conductor being longer than the second annular conductor. For example, a gap of the first annular conductor of the nozzle is greater than a gap of the second annular conductor of the nozzle. In this case, the cross section of the first annular conductor can be increased in relation to the cross section of the second annular conductor.
    [0049] The inductive coil can be wound in a spiral shape, at least in sections, and in fact, preferably, continuous with an inclination other than zero in relation to a direction parallel to the axis of the bar, being that the turns in this section pass through the lining of a cone, which is symmetrical to the axis of the bar. With a plane, which is perpendicular to the axis of the bar, the coil turns or turns can present, for example, in sections or continuously, an angle of more than 5 degrees, more than 10 degrees or more than 15 degrees.
    [0050] For the cooling of the inductive coil, a conductor that forms the inductive coil can be executed as a hollow tube, for the conduction of a coolant. A cross section of the hollow tube can be circular, oval or square. The hollow tube can be made as a double hollow tube, which comprises two separate hollow chambers, for example, for the flow back and forth.
    [0051] For the melting and spraying of electrically non-conductive materials such as ceramics, as a heating variant, a shield that follows a contour of the bar may be arranged, for example, with rotation symmetry and open in the direction the nozzle. Preferably, the shield is formed of a material resistant to high temperatures and to be inductively coupled, for example, of platinum. The shield is usually heated even inductively, and provides heat to the bar by means of thermal radiation.
    [0052] As a return conductor for unusable residual dust, material dust and shavings, the bar itself can be made as a crucible. In addition, the bar may have appropriate hollow spaces that can be filled. Such a hollow space can be, for example, a cylindrical recess in the core, into which the remaining material can be placed.
    [0053] In this way powders can be produced with a particularly narrow grain size distribution such that the spray gas is accelerated, parallel to the flow direction of the melt flow, along a relatively short acceleration stretch with a length LB, at least up to the speed of sound of the spray gas. For example, it may be worth: LB <5 ^ dmin, where dmin is the aforementioned minimum spray nozzle diameter perpendicular to the nozzle axis. Parallel to the direction of flow, the velocity v of the spraying gas, therefore, during the passage of a section with the length LB, it is changed around a value Δv, being, for example, worth: Δv> 0.9-vo , and you must indicate the speed of sound of the spray gas.
    [0054] The device suggested here may have at least one additional nozzle in addition to the spray nozzle described above, which is arranged in line with the spray nozzle, such that the melt flow can also be conducted or is conducted through the other nozzle. The other nozzle can be executed in such a way that it accelerates a gas, introduced with the melting flow in the other nozzle, in a direction parallel to the melting flow, to at least 0.5 times the speed of the sound of the gas introduced in the another nozzle, i.e. preferably in a laminar manner. For example, the other nozzle may have a cross section that is reduced in the flow direction of the melt flow in a monotonous or very monotonous manner. For example, the other nozzle can also be used as a Laval nozzle. The dimensions of the other nozzle may deviate from those of the spray nozzle. For example, a minimum cross-section of the other nozzle may be greater than the minimum cross-section of the spray nozzle.
    [0055] Preferably, the other nozzle is disposed between the material bar and the spray nozzle, therefore, in the flow direction of the melt flow before the spray nozzle. In particular, it can then be used to accelerate the gas introduced into the other nozzle even before it enters the spray nozzle. Alternatively or additionally, the other nozzle can center and / or expand and accelerate the melt flow even before it enters the spray nozzle. However, in the same way arrangements can be designed, in which the other nozzle is arranged in the flow direction of the melt flow behind the spray nozzle.
    [0056] Examples of implementation of the invention are represented in the drawings, and will be clarified in more detail with the aid of the description below. Shown are:
    [0057] Fig.1 a schematic sectional representation of a device according to the invention for melting a material and spraying the material to form dust, the device comprising a material bar, an induction coil and a spray nozzle;
    [0058] Fig. 2 is a schematic enlarged representation of the material bar, the induction coil and the spray nozzle of fig. 1;
    [0059] Fig. 3 a first special schematic embodiment of the induction coil shown in figures 1 and 2;
    [0060] Fig. 4 a second special schematic embodiment of the induction coil shown in figures 1 and 2;
    [0061] Fig. 5 a third special schematic embodiment of the induction coil shown in figures 1 and 2;
    [0062] Fig. 6 a fourth special schematic embodiment of the induction coil shown in figures 1 and 2;
    [0063] Fig. 7 is a schematic top view of the form of execution of the induction coil according to fig. 6;
    [0064] Fig. 8 a special schematic embodiment for materials not inductively coupled, for example, ceramic; and
    [0065] Fig. 9 another schematic embodiment of the suggested device, in which another nozzle is arranged in line with the spray nozzle.
    [0066] FIG. 1 schematically shows a cross-sectional representation of an example of a device 1 according to the invention for melting without a crucible of a material, in this case titanium, and for spraying the material to form powder. The device 1 comprises a container 2, in which a material bar 3, an induction coil 4 and a spray nozzle 5 are arranged. The bar 3, the coil 4 and the nozzle 5 are aligned cylindrically symmetrically, or almost cylindrically, respectively. symmetrical, and along a vertical axis 9. An axis of symmetry of the bar 3, an axis of symmetry of the coil 4 and an axis of symmetry of the nozzle 5 respectively coincide with axis 9. This passes parallel to a direction z 10, along which the force of gravity acts. Perpendicular to the z direction 10 passes an x direction or side direction 11. In particular, the coil 4 and the nozzle 5 are executed as separate components. The coil 4 is arranged above the nozzle 5, and is spaced from that nozzle along the z 10 direction.
    [0067] In this case, the material bar 3 is formed of titanium, and is partially introduced in the coil 4. A lifting / lowering device 13 is equipped to hold and move the bar 3 along the positive and negative z 10 direction. In addition, the lifting / lowering device 13 can rotate the bar 3 with a number of revolutions of up to 200 min-1 around the axis of the bar, as indicated by the arrow 14. The coil 4 picks up and wraps the bar 3 in its lower end, facing the nozzle 5. A certain cross-section of the bar perpendicular to the axis of the bar has, for example, a diameter of the bar 12 of 40 mm. In the area of turns 4a and 4b the coil 4 has a slightly larger diameter than the bar 3. In this case, the coil 4 is formed of copper, and has a number of turns 4a-d. Towards nozzle 5, turns 4a-d become narrower, at least in sections. For example, at the end of the coil 4, away from the nozzle 5, the first loop 4a has a larger diameter of the loop than the last loop 4d facing the nozzle 5.
    [0068] An internal space of the container 2 is subdivided by a separation wall 6, in a high pressure chamber 7 placed above the separation wall 6, and in a spray chamber 8 placed below the separation wall 6, being that , the high pressure chamber 7 and the spray chamber 8 are in fluid connection through the nozzle 5. The coil 4 and the material bar 3 are arranged in the high pressure chamber 7. A first pressure of the gas p1 in the pressure chamber high pressure 7 and a second gas pressure p2 in the spray chamber 8 can be adjusted by first pressure regulating means 17 and second pressure regulating means 18. The first pressure regulating means 17 comprise, for example, a high-pressure reservoir with argon, a high-pressure conductor and a high-pressure valve, through which the argon gas can be introduced into the high-pressure chamber 7. The second pressure regulating means 18 comprise, for example, a ventilation valve and a ventilation conductor! In this case, the first gas pressure p1 is set to 15 bar, and the second gas pressure p2 is set to about 1 bar, in such a way that it applies: p1 / p2 = 15.
    [0069] Coil 4 is driven with an alternating voltage of about 100 kHz from an alternating voltage source not shown in this case, and with an electrical power of about 20 kW. In this way the coil induces alternating magnetic fields in the bar 3 conducting electricity. In this way the bar 3 is heated inductively, such that at the end of the lower bar 15, facing the nozzle 5 it is melted at least on the surface. In this way, a melt flow 16 flows downwards in the z direction.
    [0070] In fig. 2 the end of the bar 15, facing the nozzle 5 of the bar 3, the coil 4 and the nozzle 5 are shown in a slightly enlarged representation. In this case, and then the recurring characteristics are provided with the same reference numbers respectively. The continuous melt flow 16 produced by inductive heating of the bar 3 flows in the z direction 10 downwards, and is introduced into the nozzle 5 through a first opening 20 of the nozzle 5, facing the coil 4 and the bar 3. The nozzle 5 is performed as Laval nozzle. The shape of the nozzle 5, in connection with the pressure difference between the first gas pressure p1 in the high pressure chamber 7 and the second gas pressure p2 in the spray chamber 8 causes an acceleration of the spray gas in the z direction 10, in this case, highlighted by the arrows 19. In this case, the spray gas 19 accelerates in the direction z 10, and through it is introduced into the nozzle 5. Since in particular, it is not necessary that the spray gas 19 be preheated, the The method suggested here can be carried out with a relatively small energy expenditure. The nozzle 5 is in fluid connection with the high pressure chamber 7 only through the first opening 20. Therefore, the spray gas 19 is introduced into the nozzle 5 exclusively through the first opening 20.
    [0071] The melt flow 16 is now picked up and centered by the spray gas flow 19 in a laminar fashion and laminarly accelerated in the z 10 direction. The melt flow 16 is then conducted together with this gas flow accelerating through the first opening 20 to the nozzle 5, and is conducted through the nozzle 5. By means of the faster spray gas 19, the buoyant stresses are transmitted to the melting which flows more slowly in the z 10 direction. This transfer takes place in an analogous way to a wall thrust tension contrary to a laminar tube flow, and in the direction of flow it causes an increase in pressure inside the melt flow 16. In the ever faster flow of the spray gas 19 on the contrary, conditioned by the shape of the Laval 5 nozzle a pressure drop occurs. As soon as the internal pressure of the melt flow 16 becomes too great, the melt flow 16 explodes and is sprayed into droplets 21. The melt flow 16 or the droplets 21 then enter through a second opening 22 of the nozzle 5 in the chamber spraying. The second opening 22 is the only fluid connection between the nozzle 5 and the spray chamber 8.
    [0072] After the droplets have cooled and frozen, then a narrowly distributed, spherical and very fine powder of the molten material appears. In the present example of execution described, a titanium powder with an average grain diameter relative to the mass of 51 μm is produced. For the breadth of the grain diameter distribution of the titanium powder produced in this way, it is worth d84 / d50 <2.6.
    [0073] An important parameter for the production of a powder of high qualitative value is the minimum nozzle cross section, characterized by the minimum internal diameter dmin (reference number 23) of the spray nozzle 5. In this case, dmin matters at -5 mm. In fig. 2 there is highlighted a plane 24 perpendicular to the axis of the nozzle 9, in which a cross-sectional surface of the nozzle is minimal and in which the internal diameter of the nozzle 5 accepts its minimum value dmin.
    [0074] In order to act against the cooling or freezing of the melt flow 16 before spraying, it is advantageous to conduct the bar 3 as close as possible to the nozzle 5. In this case, the bar 3 and the nozzle 5 are arranged in such a way that a minimum distance 25 between the plane 24 and the bar 3 is approximately only triple the dmin, therefore, about 18 mm.
    [0075] The mechanical energy fed or to be fed to the melting flow 16 for the spraying is preferably introduced, through the buoyant stresses of a flow of the spraying gas 19 that rests originally or in essence, resting, and is only introduced into the laminarly accelerated melt flow 16 together with the melt flow 16. The nozzle 5 is executed in such a way that the spray gas flow 19 remains laminar until the melt flow 16 is sprayed. The melt flow 16 then has already it is covered by the flow of the spray gas 19 even slower, accelerated, expanded and reduced along the flow direction. The energy required for spraying can now be transferred to the melt flow 16, before it flows through the nozzle 5.
    Therefore, the relatively shortest distance 25, in the case of the device described here, between the bar 3 and the plane 24 of the narrowest cross section, furthermore, causes the spraying gas to be accelerated parallel to the direction of flow of the melt flow 16 along the acceleration section, which is shorter than the distance 25 between the bar 3 and the plane 24, at least until the velocity of the spray gas sound 19. The length of the acceleration in this case therefore matters, in particular, less than triple dmin. The spray gas 19 reaches the speed of sound when it passes the plane 24 of the narrower nozzle cross section.
    [0077] Another effective measure, with which the cooling or freezing of the melt flow 16 is avoided before spraying, is to conduct the coil 4 as close as possible to the nozzle, in such a way that the melt flow 16 flows before from the entrance to the nozzle 5 as far as possible inside the coil 4, and it is surrounded or covered by at least the last loop 4d of the coil 4. In the example shown here the minimum distance amin, (reference number 26) between the end of the coil 4, facing the nozzle 5 and the plane 24 of the narrower nozzle cross section has less than the dmin bend, therefore, less than about 12 mm.
    [0078] The bar 3, the coil 4 and the nozzle 5, as shown in fig. 2, are arranged in such a way that the melt flow 16 in an area between the end of the bar 3 and the nozzle 5, facing the nozzle 5, or between the end of the bar 3 facing the nozzle 5 and the plane 24 of the the narrower cross-section of the nozzle is further heated by the coil 4, in particular, at least by the last loop 4d. Therefore, preferably, at least the last loop 4d, along the flow direction of the melt flow 16 is disposed between the end of the bar facing the nozzle 5 and the nozzle 5. The diameter of the loop of the last loop 4d in this case, it is less than 5 ^ dmin. In order to simultaneously prevent the nozzle 5 from being heated by the coil 4 close to the nozzle 5, the nozzle 5 is formed predominantly of a material, whose specific electrical resistance, for example, is greater than 2'10-2 Qm.
    [0079] The fusion of the bar 3 at its end facing the nozzle 5 occurs in the arrangement shown in fig. 2 particularly efficiently, because the turns 4b-d are aligned in sections respectively perpendicular to the axis of the bar 9. The sections of adjacent turns, aligned respectively perpendicular to the axis of the bar 9 are connected by inclined sections, which exceed respectively a value of constant G step.
    [0080] For the inductive heating of the irradiation to occur particularly effectively, it is important that a melting rate (mass per time), with which the bar 3 is melted, is sufficiently large to produce a melting flow 16 continuous. The melting rate should be, for example, at least 0.5 kg per minute or at least 1 kg per minute. Naturally, the melt rate required to produce a continuous melt flow 16 is dependent on the special properties of the melt and can vary from material to material (e.g., viscosity, surface tension).
    [0081] Figures 3 to 7 show special forms of execution of coil 4 schematically.
    [0082] FIG. 3 shows a form of execution of the coil 4, in which the turns 4b-d are spiral wound and pass in the coating 26 of an imaginary cone that is symmetrical in relation to the axis of the bar 9. In the case of a complete 360 turn degrees, in this case, each turn exceeds a step value G. A diameter of a conductor or conductive tube 27 that forms the coil 4 is designated with P. Generally G is slightly larger than P. For example, it may be true that G > 1.5-P. The conductor 27 is made as a hollow copper tube, for cooling by means of a cooling liquid. The outer diameter P of this tube can be, for example, 12 mm. A tube wall thickness can be 2 mm.
    [0083] The form of execution of bonina 4 according to fig. 4 differs from the figure according to fig. 3 in that in this case, the coil 4 comprises two conducting tubes 27a and 27b electrically connected in parallel, which, in turn, are wound respectively in a spiral shape and become conically narrow towards the lower end. In this case, the hollow tubes 27a and 27b, likewise, are formed of copper. In this case, its outer diameter P must be, however, only 6 mm. The wall thickness is only 1 mm. In this way, the conductive tubes 27a and 27b can be wound tightly together much more easily than the conductive tube 27 according to fig. 3. In this case, the value of the step G of the conductors 27a and 27b is, for example, also 18 mm, respectively, but the lower diameter du is much smaller.
    [0084] In the case of the form of execution of the coil 4 shown in fig. 5, this coil 4 comprises a conductor 28, which is executed as a double hollow tube with a rectangular cross section. A height of the cross-section of the conductor 28 is designated with H, a width with B. The double hollow tube comprises two individual hollow tubes 28a and 28b joined together, whose hollow spaces are separated, therefore, are not in fluid connection . The hollow tubes 28a and 28b have a square cross section with a side length Hi, respectively, where H = 2-Hi.
    [0085] FIG. 6 shows another form of execution of the coil 4, in which the turns 4b-d are respectively made as seals approximately in the shape of a horseshoe, each of which is aligned perpendicularly to the axis of the coil 9. The coil 4 according to fig . 6 thus produces fields with particularly high symmetry in relation to the axis of the coil 9. In this way, the material bar 3 can be cast in a particularly uniform way.
    [0086] Each of these linings forms an annular conductor, electrically interrupted at a point, which is almost closed, therefore, for example, it involves axis 9, respectively around 340 degrees. Electrical interruptions are performed as air slits 31b-d.
    [0087] The turns 4a-d are electrically connected in parallel and are executed respectively as a hollow tube, for the conduction of a cooling liquid. The hollow tubes that form the turns 4a-d are composed, respectively, of two complementary pieces in the form of L in the cross section. A cross section of each hollow tube is, therefore, in the form of a parallelogram. For example, the hollow tube 29 that forms the loop 4b is composed of the parts 29a and 29b which are connected through weld connections 30. The external and internal areas of the parts 29a and 29b in turn form cone cutouts. The internal diameters d1, d2 and d3 are reduced in the z 10 direction. Along the z 10 direction, certain intervals t1 and t2 between the turns are the same size.
    [0088] The turns 4b-d are made, respectively, of the same conductive material and have, respectively, a different circumference. For the most uniform fusion of the bar at its lower end, the flows that flow to the 4b-d turns connected in parallel in parallel can be adapted by the fact that the respectively different cross sections are given to the 4b-d turns. In this case, it is shown that the heights H1, H2 and H3 of the turns 4b-d are, respectively, different. In particular, heights H1, H2 and H3 increase linearly from bottom to top with diameters d1, d2 and d3. With this it can be obtained that in the turns connected in parallel, approximately equal flows flow, respectively, in such a way that on its surface at the lower end, the bar 3 is cast as uniformly as possible.
    [0089] In addition, the air slits 31b-d of the various turns 4b-d are rotated together around the angles α1 and α2 as can be seen from fig. 7.
    [0090] FIG. 8 shows an embodiment of device 1, with which, in particular, materials to be coupled non-inductively, for example, ceramics can be melted. For heating the bar 3 through the coil 4, a shield 32 is arranged that follows the contour of the bar, for example, with rotation symmetry and open in the direction of the nozzle. The shield 32 is formed of a material, resistant to high temperatures and to be inductively coupled, for example, of platinum. Normally the shield 32 is self-inductively heated and provides heat to the bar by means of thermal radiation. TEST RESULTS
    [0091] In a first test with an aluminum bar to be cast with a diameter d = 50 mm, with a number of revolutions of the bar with approximately 40 min-1, a power of approximately 14 kW was transmitted by a high frequency transformer , whose magnetic field was excited at approximately 105 kHz after coupling. In the case of a very good conductor nozzle, a dripping melt flow was produced and still not continuous with a spray pressure of 10 bar (gas pressure in the high pressure chamber), the position of the melting area being it was not very easy to be recognized due to the low melting temperature of aluminum.
    [0092] In another test with a 50 mm bar made of 1.4462 stainless steel, 16 kW with 101 kHz were transmitted. The number of revolutions in turn had an approximate value of 40 min-1 and the nozzle was a good conductor. In the case of a first gas pressure of 10 bar, a continuous melting flow could be produced for a short period of time and, in addition, only a flow of dripping material.
    [0093] In the case of another test with a 38 mm bar of stainless steel 1.4462, very different powers were transmitted in the range of about 25 to 35 kW with 107 kHz. The number of revolutions was in turn 40 min-1 and the nozzle was non-conducting this time, in such a way that a particularly small distance could be adjusted between the coil and the Laval nozzle. In addition, in this case, the two-stage nozzle mentioned here was used. In the case of a spray pressure of 20 bar, a continuous melt flow could be produced. In this case, the average grain size was d50 = 49 μm and d84 / d50 was 2.68.
    [0094] During the spraying of 20 mm diameter titanium bars with a spray pressure of 17 to 19 bar against the atmosphere with a non-conductive Laval nozzle with a two-stage contour, a power of approximately 35 kW was transmitted with a frequency of 112 kHz. The number of revolutions was the same as above. It resulted in an average grain size of d50 = 51.4 μm with d84 / d50 = 2.60 and a partial flow of 23.7 μm with d84 / d50 = 1.78.
    [0095] FIG. 9 shows an embodiment derived from device 1 according to fig. 1. The characteristics already described before, in particular, in the context with fig. 1 are also designated with the same reference numbers. Device 1 according to fig. 9 differs from device 1 according to fig. 1 due to the fact that along the z 10 direction between the partition wall 6 and the material bar 3, another partition wall 34 is arranged. A through opening in the other partition wall 34 forms another nozzle 33. A cut the other nozzle 33 is reduced in the positive z 10 direction and thus in the flow direction of the melt flow 16 in the form of a cone. One nozzle axis of the other nozzle 33 coincides with axis 9, such that the spray nozzle 5 and or another nozzle 33 are arranged in alignment.
    [0096] Therefore, firstly the melt flow 16 that appears at the end of the bar 15 is introduced in the other nozzle 33. That nozzle is executed in such a way that it accelerates the spray gas 19, which enters the inlet opening of the another nozzle 33, facing the material bar 3, to the other nozzle, parallel to the flow direction of the melt flow 16, therefore, along the positive z direction 10, at least 0.5 times the speed of sound of the spray gas 19. In this way, the melt flow 16 is already centered and expanded before entering the spray nozzle 5. It has been shown that this can further improve the quality of the powder produced in the spray nozzle 5, both in relation to the size of the grain obtained, and also in relation to the range of distribution of the size of the grain. In figure 9, a surface of the minimum cross-section, defined perpendicular to the axis of the nozzle 9, of the other nozzle 33 has the value of at least 5 times the surface of the minimum cross-section of the spray nozzle 5. However, shapes of the nozzle are also conceivable. another nozzle 33 diverging from that.
    [0097] In order for the other nozzle 33 (pre) to accelerate the spray gas 19 as previously described, an appropriate pressure difference is required on both sides of the separation wall 34. This difference is produced by means of the first pressure regulating means 17, and through the third pressure regulating means 35. The third pressure regulating means comprise, like the first pressure regulating means 17, a high pressure conductor and a pressure regulating valve that are connected to a high pressure reservoir with argon and, through argon gas, can be introduced in an intermediate space 36 between the separation walls 6 and 34. For example, the regulating means of pressure 17, 18 and 35 can be adjusted in such a way that the gas pressure p3 in the intermediate space 36 has the approximate value of p3 = (p1 + p2) / 2, and as previously described, p1 and p2 designate the gas pressure in the high pressure chamber 7 and in the spray chamber 8. In any case, the pressure regulating means 17, 18, 35 must be adjusted in such a way that: p2 <p3 <p1.
    权利要求:
    Claims (15)
    [0001]
    1. DEVICE (1) FOR THE MELTING OF A MATERIAL WITHOUT CRUCIBLE, and for the spraying of the molten material for the production of dust, comprising: a spray nozzle (5), configured as a laval nozzle and defining a nozzle axis (9); an induction coil (4) with turns (4a-d), which become narrower in the direction of the spray nozzle (5) at least in sections; and a material bar (3) inserted, at least partially in the induction coil (4); the induction coil (4) being equipped to melt the material of the material bar (3), for the production of a melt flow (16); and the induction coil (4) and the spray nozzle (5) are arranged in such a way that the melt flow (16) can be introduced or is introduced into the spray nozzle (5) for spraying the melt flow (16) by means of a spray gas (19), which can be introduced into the spray nozzle (5) through a first opening (20) of the spray nozzle (5); characterized in that the spray nozzle (5) is carried out in such a way that the spray gas (19) is introduced into the spray nozzle (5) only through the first opening (20) of the spray nozzle (5); wherein the spray nozzle (5) is equipped to laminarly accelerate the spray gas (19) in a direction parallel to the melt flow (16) at least to the speed of sound of the spray gas (19); wherein the spray nozzle (5) and the induction coil (4) are arranged as separate components and the induction coil (4) is spaced from the spray nozzle (5) along the axis of the nozzle (9); where the induction coil (4) and the spray nozzle (5) are arranged in such a way that amin <4 • dmin, where amin is the minimum distance between the induction coil (4) and the plane (24), which is given by the surface of the minimum cross section of the spray nozzle (5) defined perpendicular to the axis of the nozzle (9) of the spray nozzle (5), and where dmin is the minimum internal diameter of the spray nozzle (5) in the said plan (24); and in which the material bar (3), the induction coil (4) and the spray nozzle (5) are arranged in such a way that, along the axis of the nozzle, at least one loop of the induction coil ( 4) is arranged between the spray nozzle (5) and one end of the material bar (3) facing the spray nozzle (5), so that before the melt flow (16) enters the spray nozzle ( 5), the melt flow (16) can be heated or is heated inductively by the induction coil (4).
    [0002]
    2. DEVICE (1) according to claim 1, characterized by the material, from which the material bar (3) is formed, comprising metal or ceramic, the metal preferably containing aluminum, iron or titanium.
    [0003]
    DEVICE (1) according to claim 1 or 2, characterized in that the minimum internal diameter dmin (23) of the spray nozzle (5) is less than 7 mm.
    [0004]
    DEVICE (1) according to any one of claims 1 to 3, characterized in that the material bar (3) and the spray nozzle (5) are arranged in such a way that for a minimum distance L (25) between the material bar (3) and said plane (24) apply: L <5 ^ dmin.
    [0005]
    5. DEVICE (1) according to any one of claims 1 to 4, characterized in that: amin ^ 3 • dmin.
    [0006]
    DEVICE (1) according to any one of claims 1 to 5, characterized in that the spray nozzle (5) is formed of a nozzle material to minimize the amount of heat dissipated through the activity of the induction coil ( 4) in the spray nozzle (5), for whose specific electrical resistance p is: p <0, 02-10-6 Qm or p ^ 10—2 Qm.
    [0007]
    DEVICE (1) according to any one of claims 1 to 6, characterized by a high pressure chamber (7), a spray chamber (8) that is in fluid connection with the high pressure chamber (7 ), through the spray nozzle (5), first pressure regulating means (17) for the introduction of the spray gas (19) in the high pressure chamber (7), and for the regulation of a first pressure of the gas p1 in the high pressure chamber (7), as well as second pressure regulating means (18) for regulating a second pressure of gas p2 in the spray chamber (8), the first and second regulating means of pressure are equipped to adjust the pressures p1 and p2 for the acceleration of the spray gas (19) in a direction parallel to the flow direction of the melt flow (16), in such a way that it is valid: p1 / p2> 1.8 and p1> 10 bar.
    [0008]
    DEVICE (1) according to any one of claims 1 to 7, characterized by at least one of the turns (4a-d) of the induction coil (4), which is arranged in the area of one end (15) of the material bar (3), facing the spray nozzle (5) and actually preferably at least the last loop (4d) of the induction coil (4), facing the spray nozzle (5) passing perpendicular to the bar axis at least in sections, to produce the most symmetrical electromagnetic field possible in that area in relation to a material bar axis (3).
    [0009]
    DEVICE (1) according to claim 8, characterized in that at least one loop (4d) is performed as an annular conductor electrically interrupted in one place, preferably as an almost closed annular conductor.
    [0010]
    DEVICE (1) according to claim 9, characterized in that: - the device (1) comprises at least two ring conductors, and that - the at least two ring conductors are electrically connected in parallel.
    [0011]
    11. DEVICE (1), according to claim 10, characterized in that ring conductors with different circumference have different cross-sections, and / or have different distances along the coil axis, such that they have respectively an equal electrical resistance and produce the most homogeneous field distribution possible along the axis of the bar.
    [0012]
    12. DEVICE (1) according to any one of claims 1 to 11, characterized in that a conductor forming the induction coil (4) is designed as a hollow tube for conducting a coolant.
    [0013]
    13. DEVICE (1) according to any one of claims 1 to 12, characterized by at least one other nozzle (33), which is arranged in alignment with the spray nozzle (5), and which is preferably arranged, between the material bar (3) and the spray nozzle (5), such that the melting flow (16) can also be conducted or is conducted through the other nozzle (33), the other nozzle (33) 33) is equipped to accelerate a gas introduced with the melt flow (16) in the other nozzle (33) in a direction parallel to the melt flow (16) at least up to 0.5 times the speed of sound of the gas introduced in the other nozzle (33).
    [0014]
    14. METHOD FOR THE PRODUCTION OF POWDER THROUGH THE MELTING OF A MATERIAL WITHOUT A CRANE, and by spraying the molten material, by means of a device as defined in any one of the preceding claims, characterized by comprising the steps: at least partial introduction a material bar (3) on an induction coil (4) that is reduced conically at least in sections; admission of the induction coil (4) with an alternating voltage, for the melting of the material bar (3) and for the production of a melting flow (16); introducing the melt flow (16) into a spray nozzle (5) through a first opening (20) of the spray nozzle (5); and introducing the spray gas (19) into the spray nozzle (5) and spraying the melt flow (16) by means of the spray gas (19); wherein the spray gas (19) is introduced into the spray nozzle (5) only through the first opening (20) of the spray nozzle (5); the spray gas (19) to be introduced and / or introduced into the spray nozzle (5) through the first opening (20), in a direction parallel to a flow direction of the melt flow (16) is accelerated so as to laminate at least to the speed of sound of the spray gas (19), such that the melt flow (16) splits and even bursts and powder with a grain size in the micrometer range is produced and / or in the range of submicrometers; and since, before the melt flow (16) enters the spray nozzle (5), the melt flow (16) is heated inductively by the induction coil (4).
    [0015]
    15. METHOD, according to claim 14, characterized in that the spray gas (19) is accelerated parallel to the flow direction of the melt flow (16) along an acceleration section with a length LB at least to the speed of the spray gas sound (19), and for LB the following applies: LB <5 ^ dmin, where dmin (23) is the minimum diameter of the spray nozzle (5) perpendicular to the nozzle axis.
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    同族专利:
    公开号 | 公开日
    ES2769777T3|2020-06-29|
    WO2015092008A1|2015-06-25|
    EP3083107B1|2019-12-04|
    KR102304964B1|2021-09-27|
    CA2934433A1|2015-06-25|
    DE202014011339U1|2019-07-15|
    PL3083107T3|2020-06-01|
    SG11201604837YA|2016-07-28|
    US20160318105A1|2016-11-03|
    SI3083107T1|2020-04-30|
    KR20160101004A|2016-08-24|
    EP3083107A1|2016-10-26|
    DE102013022096A1|2015-06-25|
    CN105899312A|2016-08-24|
    DE102013022096B4|2020-10-29|
    US10946449B2|2021-03-16|
    CN105899312B|2019-07-09|
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    法律状态:
    2019-07-30| B06U| Preliminary requirement: requests with searches performed by other patent offices: procedure suspended [chapter 6.21 patent gazette]|
    2020-10-20| B06A| Patent application procedure suspended [chapter 6.1 patent gazette]|
    2021-01-26| B09A| Decision: intention to grant [chapter 9.1 patent gazette]|
    2021-04-13| B16A| Patent or certificate of addition of invention granted [chapter 16.1 patent gazette]|Free format text: PRAZO DE VALIDADE: 20 (VINTE) ANOS CONTADOS A PARTIR DE 19/12/2014, OBSERVADAS AS CONDICOES LEGAIS. |
    优先权:
    申请号 | 申请日 | 专利标题
    DE102013022096.3A|DE102013022096B4|2013-12-20|2013-12-20|Apparatus and method for crucible-free melting of a material and for atomizing the molten material to produce powder|
    DE102013022096.3|2013-12-20|
    PCT/EP2014/078849|WO2015092008A1|2013-12-20|2014-12-19|Device and method for melting a material without a crucible and for atomizing the melted material in order to produce powder|
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