WO2016184455A1

WO2016184455A1 - Device and method for atomizing molten materials

Info

Publication number: WO2016184455A1
Application number: PCT/DE2016/100228
Authority: WO
Inventors: Humberto Chaves; Clemens KIRMSE; Hans-Peter Heller; Tobias Dubberstein
Original assignee: Technische Universität Bergakademie Freiberg
Priority date: 2015-05-19
Filing date: 2016-05-18
Publication date: 2016-11-24
Also published as: DE102015107876A1; EP3297781A1

Abstract

The invention relates to a device and a method for atomizing molten materials. To this end, molten material (6), which passes through a gap opening (5) in order to reach an outlet opening (2.1) that is flown through by propellant fluid, is sheared when contact occurs with the propellant fluid stream (3.1) along the inner wall of the flow channel (10.2), wherein a temperature reduction of the propellant fluid stream (3.1) is compensated in an expansion region for the propellant fluid flow (3.1), which is located in the flow direction (3) and downstream of the gap opening (5), by increasing the rest temperature of the propellant fluid.

Description

Apparatus and method for atomizing melts

The invention relates to a device and a method for atomizing melts.

Powders serve as starting material in many fields of technology. With regard to the homogeneity of powders and the shape and size of particles contained therein, high quality requirements are imposed. In particular, technologies such as 3D printing or laser sintering require powders with particle diameters in the micrometer range, since the size of the particles

Structure resolution limited to manufactured structures. Also in the field of manufacturing composite materials, powders are desired which have particularly small particle sizes, since the particle sizes of the composite powders used influence the final properties of the composite materials.

Processes for the production of powders are based primarily on the gas atomization of melts, wherein a gas stream with high flow velocity is directed onto a melt in such a way that particles are sheared off from the melt. Various methods or devices of gas atomization of liquid metals and melts are known. These include, for example, the so-called free fall atomizer, in which a compact strand of a melt passes through an opening into an area in which nozzles are arranged spaced for a sputtering gas. Another nebulizer, called the Closed Coupled Atomizer, includes a plurality of gas nozzles positioned near a melt outlet port to achieve the desired melt slugging efficiency.

In another atomizer variant, the procedure is such that a melt strand and the gas are passed through a Laval nozzle, wherein the

Gas is greatly accelerated compared to the melt. Due to the increased relative velocity between gas and melt, greater shear forces are achieved, which contribute to improved atomization.

According to general opinion, the process of atomization can be divided into at least two stages. In the field of primary atomization, in When the gas flow hits the melt, the first relatively large particles (drops, fragments) are dissolved out of the melt. In the subsequent area of the secondary atomization, the relative velocity still present causes a further division of the products of the primary atomization by aerodynamic forces into even smaller particles.

However, the problem with the process described above is that the gas accelerated by means of a Laval nozzle cools very strongly in the expansion region. Since the working range of the primary and secondary atomization can preferably also be in this range, the products of the primary atomization abruptly cool and solidify before a secondary atomization to the desired extent has taken place.

So far, the problem is solved by heating the melt above the melting temperature (overheating), which delays the solidification of the particles in the expansion area. However, the resulting delay is not sufficient to achieve a satisfactory dispersion of the particles in the micrometer range. Furthermore, the problem arises that the relatively high temperature difference in the expansion or working range leads to a rapid solidification of the surface of still molten particles inside.

Another solution is shown in EP 1 190 996 A2, which also deals with the problem of solidification of melts in the outlet region of Laval nozzles. Proposed is a device for atomizing melts, in particular slag melts, in which the melt passes through an annular gap into a gas flow-through, designed as a Laval nozzle outlet opening. A solidification of the melt in the region of the annular gap is counteracted in particular by setting a dip tube designed to convey the gas into rotation in the region of the annular gap. Within the rotating dip tube, a lance is arranged, via which the propellant gas is conveyed into the outlet opening. The proposed solution requires an increased apparatus or design effort, which is considered to be disadvantageous in terms of the associated higher costs. The solution described in EP 1 190 996 A2, like the solutions described in DE 10 2004 001 346 A1 and WO 02/04154 A1, requires the arrangement of the lance, via which the propellant gas is conveyed into the outlet opening, in a dip tube.

It is therefore an object to provide possibilities for the atomization of melts with which, in particular, small particle sizes in the micrometer range can be provided in a simple manner.

According to the invention the object is achieved with a device according to the features of the independent claim 1 and a method according to the features of the independent claim 11. Advantageous embodiments and further developments of the invention can be realized with features described in the subordinate claims.

The inventively proposed device for atomizing melts comprises a crucible with at least one outlet opening, which has an at least partially diverging flow channel in the flow direction, and a flow channel driving fluid tube for conveying driving fluid into the outlet opening, wherein the driving fluid tube is arranged such that between the Lower edge and / or the outer periphery of the Treibfluidrohrs and the inner edge and / or the inner circumference of the outlet opening a gap opening for the passage of molten material is formed. According to the invention, the device further comprises a heating device with which a quiescent temperature of the drive fluid can be adjusted and / or regulated such that a temperature change in the flow channel of the drive fluid tube and in the flow channel of the outlet port, in particular in the region of the diverging flow channel, can be compensated.

It is not necessary that the Treibfluidrohr is arranged in a tube, for example a dip tube. Rather, the outer walls of the drive fluid tube provided according to the invention can be in direct contact with the melt when the melt is in the crucible. In the case of the quiescent temperature described above, the temperature which the driving fluid has before leaving the heating device and entering the flow channel of the driving fluid tube or into the flow channel of the outlet opening is to be understood below. It should also be noted that in particular the region of the flow channel with a divergent flow cross-section is referred to as an expansion region.

The advantage of the device according to the invention consists first of all in the fact that, due to the gap opening formed between the drive fluid tube and the outlet opening, the melt entering the outlet opening forms a thin melt film which ensures an enlarged shear surface with the fluid flow. The shear rate is particularly high here, because on the wall of the divergent flow channel, the speed of the melt film is low or equal to zero and very high on the side facing the drive fluid. The shear rate is given by the quotient of the difference between these speeds and the thickness of the melt film.

The drive fluid tube and / or the crucible can be designed to be adjustable in height for adjusting a distance between the drive fluid tube and the crucible. This is necessary to ensure opening and closing of the gap opening and / or a change in the size of the gap opening. Accordingly, a lifting device can be provided, with which at least the driving fluid tube or crucible is adjustable in height so that the relative distance between the driving fluid tube and melting crucible is variable.

In an advantageous embodiment of the device according to the invention, the opening of the gap opening is not achieved by a height adjustment of the Treibfluidrohrs or crucible, but by melting a arranged in the gap opening sealing ring having a melting temperature corresponding to the melting temperature of the melt or above the melting temperature of the melt lies.

Preferably, the shape of the lower edge and / or the shape of the outer circumference of the drive fluid tube and the shape of the inner edge and / or the shape of the inner circumference of the outlet opening is formed such that when a height adjustment of the Treibfluidrohrs and / or the crucible, a fluid-tight Closing the gap opening is guaranteed. Preferably, the drive fluid tube and the outlet opening are arranged coaxially.

Furthermore, it can be provided that the shape of the lower edge and / or the shape of the outer circumference of the drive fluid tube and the shape of the inner edge and / or the shape of the inner circumference of the outlet opening are formed such that the gap formed by the distance between Treibfluidrohr and outlet opening different Shapes preferably has a ring shape.

A further advantage is in particular in the heating device, with which the rest temperature of the driving fluid is adjustable and / or regulated so that a caused by an expansion of the fluid flow in the region of the divergent flow channel cooling of the fluid flow is compensated / compensated. In this way, disadvantages known from the prior art, such as the freezing or clogging of the outlet opening or of the annular gap can be reduced, without requiring additional heating or overheating of the melt in the region of the outlet opening.

The devices and sensors required for regulating the quiescent temperature are well known and will not be discussed further here.

As a result of the adaptation / compensation of the temperature in the flow channel of the drive fluid tube and in particular in the expansion region of the flow channel of the outlet opening, a working region can be defined in the flow direction of the drive fluid at least in the region of the flow channel of the outlet opening, in which a predeterminable working temperature can be maintained. Advantageously, this can define a region in which a favorable working temperature for the atomization of the melt is ensured. For such a work area, different operating temperatures, for example for different melts and / or atomization parameters (in terms of particle shape and particle size) can also be set.

According to an advantageous embodiment of the device according to the invention, the quiescent temperature can be controlled such that the working temperature in the working range not below 70% of the melting temperature of the melt, preferably at least 100% of the melting temperature of Melted, particularly preferably maintained at least 130% of the melting temperature of the melt. The possibility that the temperature of the driving fluid can be kept close to the melting temperature of the melt, has a favorable effect on the primary and secondary atomization of the melt.

The driving fluid tube is preferably arranged in the device according to the invention so that the main flow direction of the driving fluid is directed coaxially to the central axis of the outlet opening. Preferably, the mouth of the Treibfluidrohrs is arranged in the flow direction of the driving fluid in front of the mouth of the outlet opening. In this case, a flow channel of the Treibfluidrohrs in the mouth direction, i. have a constant flow cross-section in the direction of the outlet opening.

It is particularly favorable if the flow channel of the drive fluid tube has a convergent flow cross-section in the direction of the opening. In this case, a drive fluid flow channel formed from the drive fluid tube and the outlet opening may be designed in the form of a Laval nozzle, wherein the smallest flow cross section is formed in the region of the gap opening or at the mouth of the flow channel of the drive fluid tube. The divergent part of the Laval nozzle need not be located in the crucible, but the diverging flow channel may be formed in a discharge stone, which is connected at the outlet opening interchangeable with the crucible. The outlet brick is preferably connected to the crucible with a correspondingly temperature-stable adhesive or kit. It can be provided Auslaufsteine having different slopes or geometries of the diverging flow channel. Thus, nozzles with different properties can be provided. It is also advantageous that the manufacturing technology complex geometry of a flow channel does not have to be formed in the crucible, but is provided in the form of a reusable Auslaufsteine. Due to the shape of the flow channels, particularly high flow velocities for the driving fluid can be achieved, which contributes to an increase in the relative velocity between the melt and the driving fluid. The increased shear effect has a positive effect on the primary and secondary from secondary atomization and contributes to the formation of very small particle sizes.

According to a further advantageous embodiment of the device according to the invention, at least one further outlet opening for a further fluid flow is provided in the inner wall of the outlet opening, at the mouth of the outlet opening and / or in the crucible, which at least partially flows through the driving fluid flow and / or the working area in its spatial extent limited. For limiting and influencing the working area, it is also possible to provide a plurality of further fluid streams which are provided by flexible hoses at different positions in the working area. Due to the fact that the motive fluid flow in the working area can be influenced and / or limited by means of further fluid flows, it is possible to influence the particle shape and / or particle size during atomization of the molten mass. The already mentioned heating device can be formed with an electrical resistance heater, with a plasma torch and / or with a chemical burner.

For certain applications of the device according to the invention, a protective gas atmosphere may be required. Accordingly, means for providing a protective gas atmosphere may be provided. Conceivable is a realization by inert gas flows in desired areas. Suitably, the device according to the invention can also be arranged in a container or surrounded by an enclosure, in which a protective gas atmosphere, for example. Provided with argon.

All components of the device according to the invention, which come into contact with the melt or with the heated blowing fluid flow, are formed from a temperature-resistant material, preferably a ceramic, or have a suitably temperature-resistant coating.

In the method according to the invention for atomizing melts, the procedure is such that molten material which passes through a gap opening into a flow channel of an outlet opening through which fluid flows - which may preferably have a flow cross section which at least partially diverges in the direction of flow - contacts the driving fluid flow along the inner wall of the Flow channel is accelerated, with a Temperature change of the driving fluid flow is compensated for at least in the flow channel of the outlet opening by adjusting a quiescent temperature of the driving fluid.

The melt, which may be a metallic or non-metallic material, should at least be brought to a temperature at which sufficient flowability is ensured.

Advantageously, the melt flows not as a compact strand, but as a thin film along the inner wall of the flow channel of the outlet opening, wherein the melt film on the contact side with the Treibfluidstrom against the wall side is greatly accelerated, which facilitates the shear of the melt film and favors the primary atomization.

Advantageously, the quiescent temperature is increased with the heater so far that caused by the expansion of Treibfluidstroms temperature reduction in the flow channel of Treibfluid raw rs and especially in the expansion region in the further flow, in which preferably the primary atomization of the melt can take place, adjusted or compensated for a predetermined temperature can be. The quiescent temperature is kept substantially above the melting temperature of the melt. In this way, the solidification of formed particles can be delayed in regions, in order to bring about the desired sputtering success, in particular in the area of secondary atomization (in terms of particle shape and / or particle size).

Furthermore, in the direction of flow of the driving fluid at least in the expansion region-in particular in the region with diverging flow cross-section of the flow channel of the outlet opening-a working region can be defined in which a prescribable operating temperature of the driving fluid is maintained.

An influence on the atomization process can be adjusted and / or regulated by a change in the quiescent temperature of the drive fluid. It is particularly favorable if the propellant fluid at rest above the

Melting temperature of the melt is heated to keep a temperature drop below a predetermined operating temperature in the expansion range low. Accordingly, the quiescent temperature can be adjusted and / or regulated that in the working range a working temperature can be maintained, which is not below 70% of the melting temperature of the melt, preferably at least 100% corresponds to the melting temperature of the melt, more preferably at least 130% corresponds to the melting temperature of the melt. In this case, physical and / or chemical properties of different melts should be taken into account in order to ensure the desired sputtering success.

To control the temperature change, temperature monitoring may be performed at various positions along the flow path of the motive fluid stream, providing temperature information to the heater.

According to one embodiment variant of the method according to the invention, the driving fluid in the region of the annular gap and / or in the region of the outlet opening in the flow channel can be accelerated to 50% of the speed of sound. Preferably, the flow rate of the motive fluid can also be accelerated to the speed of sound, most preferably to 200% sonic velocity. Advantageously, the flow velocity of the driving fluid can be varied as an influencing variable of the atomization process. If there is sound velocity in the region of the annular gap, the flow parameters in the flow channel of the driving fluid tube are defined by known gas-dynamic relationships.

The working area may extend from the gap opening in the flow direction of the driving fluid flow. According to a further advantageous embodiment variant of the method according to the invention, the working range of at least one further fluid flow, which flows through the driving fluid flow at least in regions, can be limited and / or influenced. This makes it possible to set the boundaries of a workspace.

It is also possible to define work areas through which different temperature-controlled fluid flows, so that such work areas can have more than one temperature zone. Flows of further fluid streams may also be directed such that within the working Rich advantageous flow conditions are caused, for example, affect the residence time of particles in the work area.

Conveniently, the at least one further fluid stream may have a temperature and / or flow velocity which is unequal to the flow of the blowing fluid. A limitation of the working range can preferably be achieved with a further fluid flow having a lower temperature than the driving fluid flow. Not belonging to the work area are understood areas in which the desired working temperature can not be met. Such areas may be formed as defined cooling areas for cooling the particles.

In a further advantageous embodiment of the method according to the invention, the quiescent temperature can be regulated as a function of the flow velocity of the drive fluid at the gap opening and / or as a function of the flow velocity of the drive fluid in the expansion region.

According to the invention, a driving fluid is understood as gas or vapor. Preferably, the driving fluid used is mono- and / or polyatomic gases and / or vapors.

The invention will be explained in more detail by way of example with reference to FIG. 1, which shows a schematic representation of an exemplary embodiment of the device according to the invention.

1 shows a device for atomizing melts, which has a crucible 1 with at least one outlet opening 2.1. In the flow direction 3 (arrow direction) of the drive fluid, the outlet opening 2.1 has a flow channel 10.2 with a diverging flow cross-section. The flow channel 10.2 is located centrally within a discharge block 17, which is cemented with a cement attached to the outlet opening 2.1 at the crucible 1. Furthermore, the device comprises a drive fluid tube 4 with flow channel 10.1 for conveying propellant fluid into the outlet opening 2.1. In this case, the drive fluid pipe 4 is arranged such that between the outer circumference of the drive fluid pipe 4 tapering in the direction of flow 3 or in the direction of the opening and the inner circumference of the outlet opening 2. 1 5 gap is formed to the flow of melt 6 in the outlet 2.1.

In the case of the embodiment of the device shown here, the drive fluid tube 4 is set up in a height-adjustable manner, so that the size of the annular gap 5 can be varied by means of the lifting device 18 in the direction of the arrow 18.1. The

Height adjustability is advantageous in order to keep the annular gap 5 closed as tightly as possible during the melting process. Only when the melt has reached the desired temperature or flowability, the Treibfluidrohr is raised by means of the lifting device 18 and the annular gap 5 is opened, so that the melt 6 can get into the outlet opening 2.1.

Reference number 7 shows a heating device connected to the drive fluid tube 4, with which a quiescent temperature of the drive fluid supplied via an inlet opening 8 can be adjusted and / or regulated such that a temperature change of the motive fluid flow 3.1 at least in the flow channel 10.2, i. in the expansion region, in which the flow channel 10.2 between the mouth of the outlet opening 2.1 and the mouth of the outlet opening 2.2 has a diverging course, can be compensated. The data acquisition required for regulating the quiescent temperature takes place by means of temperature sensors (not shown) which can be arranged in the region of the flow channels 10.1 and 10.2 and in the flow direction 3 behind the mouths of the outlet openings 2.1 and / or 2.2 or directed towards these areas.

The heating device 7 may be formed with an electrical resistance heater, a plasma torch and / or a chemical burner, depending on the type of drive fluid, which rest temperature and / or which melt are used.

According to the exemplary embodiment shown here, the flow channel 10. 1 has a flow cross section that is constant in the flow direction 3. In an embodiment not shown here, the flow channel has a converging flow cross-section. In this case, the flow channels 10.1 and 10.2 form a common flow channel for driving fluid in the form of a Laval nozzle, the smallest flow cross section at the Mouth of Treibfluidrohrs 4 is formed.

In the present example, two further flow channels 11 for fluid flows 11.1 are formed in the region of the outlet of the outlet block 17 by the arrangements 16 (cooling device), the openings 12 of the flow channels 11 being directed toward the mouth region of the outlet opening 2.2 in order to influence the driving fluid flow 3.1. The arrangement of the orifices 12 makes it possible, with a suitable flow velocity, for a crossing 9 of the fluid flows 11.1 in the region of the driving fluid flow 3.1. This makes it possible, the Treibfluidstrom 3.1 in one for the primary and

Secondary atomization favorable work area A (hatched shown) limit. In the example of FIG. 1, the working region A is formed between the outlet opening 2.1 and the intersection 9 of the fluid streams 11.1. For this purpose, temperature sensors (not shown) are directed at the working area A or arranged there in order to ensure a data acquisition of the heating device 7 required for the quiescent temperature control.

An example of the method according to the invention will now be explained in more detail by way of example with reference to FIG.

First, a fusible material is melted by supplying energy in the crucible 1. In this case, a sufficient supply of energy should be provided, so that the melt 6 reaches a suitable flowability to reach after lifting the Treibfluidrohrs 4 through the thus opened annular gap 5 in the flow from the drive fluid flow 3.1 3.1 outlet. At this point of entry into the outlet opening 2.1, the driving fluid flow 3.1 has a speed of sound, so that the incoming melting material 6 is accelerated as a result of the driving fluid flow 3.1. In this case, aerodynamic forces that urge the melt to the inner wall of the flow channel 10.2 act. It forms a thin film or a thin layer of

Melt, the wall side has a significantly lower flow velocity. The difference in flow-side flow velocity causes shear stresses within the melt film which tend to break the melt film and thereby induce primary atomization. Thus, the primary atomization of the melt can already begin immediately after entry into the outlet opening 2.1, whereby drops 13 of the melt 6 are entrained with the blowing fluid stream 3.1. At the outlet of the outlet opening 2.2, the first Mach joints 14 are indicated, which cause a further division (secondary atomization) of formed droplets. Mach's shocks are unsteady pressure, density and velocity changes when transitioning from supersonic to subsonic flow. In the further course of the flow, the fluid flows 11.1, which have a lower temperature than the driving fluid flow 3.1, meet the drops 13 at the point of intersection 9 and cool them. At the interfaces between the fluid streams 11.1 and the driving fluid stream 3.1, the temperature change in the cooling and mixing region 15 leads to the solidification of the particles formed. Thus, the secondary atomization is interrupted and limited in the present case, the work area.

A compensation of the temperature change caused in the flow channel 10.2 due to the expansion of the Treibfluidstroms 3.1 below a favorable for the primary and / or Sekundärzerstäubung working temperature is done by regulating or increasing the rest temperature of the driving fluid to the heater 7. In this case, the regulation of the rest temperature based on Temperature sensors are made or preset, if appropriate tabular values are available.

The following table shows an example of a presetting of the temperature T ₀ by means of the heating device 7 in order to obtain a temperature equal to the melting temperature T _s at the outlet opening 2.1 in the expansion region of the motive fluid stream 3.1 at a flow velocity of the motive fluid. The compensation is based on the relationship:

(1) T ₀ = (1 + (kl) / 2) T _s where k is the adiabatic exponent, T _{0 is} the quiescent temperature and T _{s is} the temperature at the speed of sound of the motive fluid. Fluid Adiabatic Fluid Example Exponent Quiescent Temperature

to

Noble gas, monatomic 1.66 To = l, 33T _s Argon, helium

Diatomic gas 1.40 T "= l, 2Ts air, nitrogen

Table 1: Required rest temperature at the speed of sound of the motive fluid

Table 1 above illustrates the relationship between the required quiescent temperature of the motive fluid and the melting temperature (in degrees Kelvin), depending on the type of motive fluid used for primary atomization.

In one embodiment of the method according to the invention, the melt is heated above its melting temperature. In this case, less energy needs to be expended for the temperature adjustments in the expansion area. It may be sufficient if the quiescent temperature is set below the melting temperature of the melted material 6. It should be noted that the risk of freezing increases with decreasing fluid temperature. This may require an adjustment of the size of the annular gap 5.

Depending on the melting material and the driving fluid, different temperature relationships result, which can be determined empirically in the application.

If a specific particle size and / or particle shape is to be realized, a working region A is defined as a function of the driving fluid and melt 6, in which particularly favorable conditions for the primary and secondary atomization of the melt can be provided. In this case, the quiescent temperature is adjusted so that the working temperature in the working area A, which can be located according to Figure 1 between the outlet port 2.1 and the intersection 9 of the fluid streams 11.1, not below. For particularly small particles, the working temperature is set above the melting temperature of the melt. Depending on the type of melting material, different quiescent temperatures may be required for the temperature adjustment or temperature compensation. Thus, it has been found that the energy required to melt tin or copper can be provided by means of resistance heating. For melting of ceramic materials higher temperatures are required, which can be achieved for example with a plasma torch. In this case, it makes sense to overheat the melt before entering the outlet opening 2.1.

Claims

claims

A device for atomizing melts, comprising a crucible (1) with at least one outlet opening (2.1) which has a flow channel (10.2) at least partially diverging in the flow direction (3), and a drive fluid pipe (4) with flow channel (10.1) Conveying drive fluid into the outlet opening (2.1), whereby the drive fluid tube (4) is arranged such that a gap opening (2) is formed between the lower edge and / or the outer circumference of the drive fluid tube (4) and the inner edge and / or inner circumference of the outlet opening (2.1). 5) to the flow of molten material (6) is formed, and a heating device (7), with a rest temperature of the driving fluid is adjustable and / or regulated so that a change in temperature of the driving fluid flow (3.1) in the flow channels (10.1 / 10.2) compensated is.

2. Apparatus according to claim 1, characterized in that in the flow direction (3) of the driving fluid at least in the flow channel (10.2) of the outlet opening (2.1), a working area (A) is formed, in which a predetermined operating temperature of the driving fluid flow (3.1) is maintained.

3. Device according to one of the preceding claims, characterized in that the rest temperature is regulated so that the working temperature in the working range (A) not below 70% of the melting temperature of the melt (6), preferably at least 100% of the melting temperature of the melt ( 6), more preferably at least 130% of the melting temperature of the melt (6) is maintained.

4. Device according to one of the preceding claims, characterized in that the driving fluid tube is arranged coaxially to the central axis of the outlet opening.

5. Device according to one of the preceding claims, characterized in that a flow channel (10.1) of the Treibfluidrohrs (4) in the mouth direction has a constant, preferably converging flow cross-section.

6. Device according to one of the preceding claims, characterized in that the flow channels (10.1 / 10.2) are formed in the form of a Valve nozzle, wherein the smallest flow cross-section at the mouth of the flow channel (10.1) of the driving fluid tube (4) is formed.

7. Device according to one of the preceding claims, characterized in that at least one further outlet opening (12) for at least one further fluid flow (11.1) is provided which flows through the driving fluid flow at least partially and / or limits the working area in its spatial extent.

8. Device according to one of the preceding claims, characterized in that the Treibfluidrohr (4) and / or the crucible (6) for adjusting a distance between the Treibfluidrohr (4) and the crucible (6) are designed adjustable in height.

9. Device according to one of the preceding claims, characterized in that the flow channel (10.2) in an outlet stone (17) is formed, which is connected to the outlet opening (2.1) interchangeable with the crucible (6).

10. Device according to one of the preceding claims, characterized in that the heating device (7) is formed with an electrical resistance heater, with a plasma torch and / or with a chemical burner.

11. A method for atomizing melts, wherein the melt (6) passing through a gap opening (5) into a flow channel (10.2) of an outlet opening (2.1) through which the drive fluid flows is in contact with the drive fluid flow (3.1) along the inner wall of the Flow channel (10.2) is accelerated, wherein a temperature change of the Treibfluidstroms (3.1) at least in the flow channel (10.2) is compensated by adjusting the rest temperature of the driving fluid.

A method according to claim 11, characterized in that in the flow direction (3) of the driving fluid at least in an expansion region of the flow channel (10.2), a work area (A) is formed in which a predetermined operating temperature of the driving fluid flow (3.1) is maintained.

A method according to claim 11 or 12, characterized in that the rest temperature of the driving fluid is adjusted such that in the working range (A) a working temperature is maintained which is not below 70% of the melting temperature of the melt (6), preferably at least 100% of Melting temperature of the melt (6) corresponds, more preferably at least 130% of

Melting temperature of the melt (6) corresponds.

A method according to claim 11 to 13, characterized in that the driving fluid in the flow channel (10.2) is accelerated to at least 50% of the speed of sound, preferably to the speed of sound, more preferably to 200% speed of sound.

A method according to claim 11 to 14, characterized in that working area (A) of at least one further fluid flow (11.1), which at least partially flows through the driving fluid flow (3.1), is limited.

Method according to the preceding claim, characterized in that the at least one further fluid flow (11.1) has a relation to the driving fluid flow (3.1) unequal temperature, preferably lower temperature.

A method according to claim 11 to 16, characterized in that the rest temperature as a function of the flow velocity of the driving fluid flow (3.1) at the gap opening (5) and / or in dependence on the flow velocity of the driving fluid flow (3.1) in the expansion region, is regulated. A method according to claim 11 to 17, characterized in that preferably used as driving fluids and other fluids mono- and / or polyatomic gases and / or vapors.