Device for providing plasma

Abstract

The present invention relates to a device (6) for providing plasma, comprising at least one plasma generating element (8), on and / or within which at least one electric induction coil (10) and / or magnetron is arranged, and within which a first flow path (11) and a second flow path (12) concentric therewith are further arranged, the second flow path (12) at least partially surrounding the first flow path (11), the first flow path (11) being fluidly connected to a first connection (16) for a gaseous fluid in order to form a heated gas flow or a plasma flow, and the second flow path (12) being fluidly connected to a second connection (17) for a gaseous fluid in order to establish a protective volume flow between a surface (14) of the plasma generating element (8) and the heated gas flow or plasma flow.

Description

[Technical Field]

[0001] The present invention relates to a device for providing plasma, comprising at least one plasma generating element, on and / or within which at least one electric induction coil and / or magnetron is arranged, and further within which a first flow path and a second flow path concentric therewith are arranged, the second flow path at least partially surrounding the first flow path, the first flow path being in fluid communication with a first connection for a gaseous fluid to form a heated gas flow.

[0002] The invention also relates to a device for the thermal treatment of materials, in particular solids, comprising at least one device for providing a plasma.

[0003] Furthermore, the present invention relates to a method of operating a device for providing a plasma for thermally treating a material, the method comprising the steps of providing a gaseous fluid in at least one plasma generating element of the device, generating a plasma in the plasma generating element, providing a hot fluid stream by heating the gaseous fluid with the plasma, optionally with the plasma to form a hot gas, and directing the hot fluid stream onto the material to be treated outside the plasma generating element. [Background technology]

[0004] The use of so-called plasma torches of various designs for melting materials, in particular metals, has already been described in the prior art.

[0005] For example, German Patent Application Publication No. 102020202484 (Patent Document 1) describes a device for melting metals having a melting temperature of less than 1000°C, in which a device for forming plasma is arranged in a melting furnace, the device is connected to a voltage supply and a first supply for at least one plasma gas using which the plasma can be formed, and the device is shaped, dimensioned, positioned, and / or aligned so that the formed plasma is positioned at a distance from the metal as the melting material, and at the same time, a high-temperature gas flow can be formed using the plasma, and the high-temperature gas flow is aligned toward the melting material, and further, a crucible or melting tank for containing the molten metal is arranged in the melting furnace.

[0006] From EP 1 433 366 A1, an induction plasma torch is known, which comprises a tubular torch body with a proximal end and a distal end and with a cylindrical inner surface having a first diameter, and a plasma containment tube, made of a material with high thermal conductivity, defining an axial chamber for containing high-temperature plasma and having a cylindrical outer surface with a second diameter slightly smaller than the first diameter, the plasma containment tube being mounted inside the tubular torch body. a plasma containment tube having cylindrical inner and outer surfaces oriented coaxially relative to one another to define a thin annular chamber having an equal thickness between the inner and outer surfaces; a gas distributor head attached to the proximal end of the torch body for introducing at least a gaseous substance into the axial chamber defined by the plasma containment tube; and a cooling fluid supply connected to the thin annular chamber for forming a high velocity cooling fluid flow within the annular chamber, the cooling fluid flow being regulated by a high thermal conductivity of the material forming the plasma containment tube. a cooling fluid supply source, in which both the conductivity and the high velocity flow of the cooling fluid contribute efficiently to heat transfer from the plasma containment tube heated by the high temperature plasma to the cooling fluid, thereby efficiently cooling the plasma containment tube; a first current supply having a high frequency output; a second current supply having a low frequency output with first and second connections; and a series of induction coils, the series of induction coils being disposed substantially coaxially with the tubular torch body between the proximal and distal ends of the torch body, the series of induction coils being disposed in an axial chamber through which a small amount of heat is supplied. a series of induction coils including a first induction coil connected to the high frequency output of the first current supply to apply inductive energy to at least one gaseous substance, and a plurality of second induction coils disposed between the first induction coil and the distal end of the tubular torch body, each having suitable terminals; and an interconnecting circuit disposed between the first and second terminals of the low frequency output of the second current supply and the terminals of the second induction coil, whereby the second induction coils are connected in a series and / or parallel arrangement with each other between the first and second terminals;and an interconnection circuit whereby an input impedance of the second induction coil is substantially matched to an output impedance of the second current supply and inductive energy is applied to at least one gaseous substance supplied into the axial chamber.

[0007] U.S. Patent Application Publication No. 2004 / 0107796 (Patent Document 3) describes a plasma-assisted melting method that includes forming a plasma in a cavity by exposing a first gas to electromagnetic radiation at a frequency less than about 333 GHz in the presence of a plasma catalyst, heating a second gas with the plasma, adding a solid to a melting bath, and directing at least enough of the heated second gas toward the solid to melt the solid.

[0008] From DE 69216970 A1 (DE69216970T2) an induction plasma torch is known, which comprises a tubular torch body with a cylindrical inner surface having a first diameter, a plasma containment tube made of a thermally conductive ceramic material and having a first end, a second end and a cylindrical outer surface having a second diameter smaller than the first diameter, the plasma containment tube being arranged within the tubular torch body and forming an annular chamber between the cylindrical inner and outer surfaces, and a gas distributor attached to the tubular torch body at the first end of the plasma containment tube and configured to separate the plasma containment tube from the plasma containment tube. a gas distributor for supplying at least one gaseous substance to the inlet tube, the at least one gaseous substance flowing through the plasma containment tube from its first end to its second end; an induction coil, to which current is supplied, thereby supplying inductive energy to the at least one gaseous substance flowing through the plasma containment tube, thereby generating and maintaining a plasma within the containment tube, the induction coil being coaxial with the cylindrical inner and outer surfaces of the annular chamber; and a device for generating a cooling fluid flow within the annular chamber, the induction coil being embedded within the tubular torch body, and the cylindrical inner and outer surfaces being machined coaxially so that the annular chamber has a uniform thickness.

[0009] EP 3314989 (Patent Document 5) describes an induction plasma torch, which includes a tubular torch body having an upstream section and a downstream section, each defining an inner surface; a plasma containment tube disposed inside the tubular torch body, coaxial with the tubular torch body, and having inner and outer surfaces with constant inner diameters; a tubular insert attached to the inner surface of the downstream section of the tubular torch body and having an inner surface; and an annular passage defined between the inner surface of the upstream section of the tubular torch body and the inner surface of the tubular insert and the outer surface of the plasma containment tube, the annular passage being configured to guide a cooling fluid for cooling the plasma containment tube, and the plasma containment tube having a tubular wall with a thickness that gradually decreases in the axial direction of the plasma flow over at least one section of the plasma containment tube.

[0010] EP 2671430 (Patent Document 6) describes an induction plasma torch, which includes a tubular torch body having an inner surface, a plasma containment tube disposed coaxially within the tubular torch body, the plasma containment tube having an outer surface, a gas distributor head disposed at an end of the plasma containment tube and configured to supply at least one gaseous substance into the plasma containment tube, and a gas distributor head configured to supply at least one gaseous substance to the plasma containment tube to generate and maintain plasma within the plasma containment tube. The capacitive shield includes an inductive coupling member for applying energy, and a capacitive shield having a film of conductive material, the film of conductive material being applied to the outer surface of the plasma containment tube or the inner surface of the tubular torch body, the film of conductive material being segmented into axial strips, the axial strips being interconnected at one end, and the inductive coupling member is embedded inside the tubular torch body, and axial grooves are formed on the outer surface of the plasma containment tube or the inner surface of the tubular torch body, each axial groove being positioned between a pair of laterally adjacent axial strips. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] German Patent Application Publication No. 102020202484 [Patent Document 2] European Patent Application Publication No. 1433366 [Patent Document 3] US Patent Application Publication No. 2004 / 0107796 [Patent Document 4] German patent number 69216970 [Patent Document 5] European Patent No. 3314989 [Patent Document 6] European Patent No. 2671430 Summary of the Invention [Problem to be solved by the invention]

[0012] The object of the present invention is to provide an improved method for heat treating materials. [Means for solving the problem]

[0013] The problem of the present invention is solved by means of the above-mentioned device for providing plasma, wherein the second flow path is fluidly connected to a second connection for a gaseous fluid in order to establish a protective volume flow between the surface of the plasma generating element and the heated gas flow.

[0014] Furthermore, the object of the present invention is solved by means of a device for thermally treating a material as described above, which comprises a device for providing a plasma according to the present invention.

[0015] Finally, the object of the present invention is achieved by the above-mentioned method, in which it is provided that the gaseous fluid in the plasma generating element is guided in the form of a central gas flow surrounded by a protective gas flow.

[0016] The advantage here is that the walls of the plasma generating element can be more easily and better protected against overheating by the protective gas flow. At the same time, however, it is possible to provide a central gas flow with a significantly higher temperature so that, if necessary, more energy can be introduced into the material to be heat-treated. The shape of the plasma torch can also be influenced by the protective gas flow. This also makes it easier to supply various gaseous fluids to the plasma generating element.

[0017] In order to improve the efficiency of the protective action of the protective gas flow, a variant of the invention can provide that the second flow path is formed by the plasma generating element itself, which also allows for a simplified design of the plasma generating element.

[0018] According to another variant of the invention, at least one other flow channel is arranged in the plasma generating element, the other flow channel being fluidly connected to another connection for another gaseous fluid, the other flow channel being arranged to extend obliquely relative to the first flow channel, at least in the end section facing the first flow channel, and the temperature of the hot gas flow and / or the plasma flow formed from the protective gas flow and the central gas flow can be changed by supplying the other gaseous fluid through the at least one other flow channel. Alternatively, according to a variant of the method, for this purpose, the other gaseous fluid can be added to the gaseous fluid formed from the protective gas flow and the central gas flow in the plasma generating element. In addition to the advantage of being able to easily change the composition of the process gas for plasma generation, this also provides a simple means for adjusting the temperature of the plasma torch, thereby making it easier to adjust the plasma generating device to various heat treatments or various materials to be treated. Furthermore, it can also be used to change or adjust the position of the plasma torch.

[0019] To improve these effects, according to a variant, it may be provided that at least the terminal section of the other flow path has an angle with the first flow path selected from the range of 5° to 80°.

[0020] In order to simplify the design of the plasma generating element, a variant of the invention may provide that a number of other flow paths, in particular four other flow paths, are arranged distributed along the circumference defined by the second flow path.

[0021] For the same reason, according to a variant, it can be provided that each of the channels extends over an annular segment selected from the range of 2° to 88°, which makes it easier to control the change in the position of the plasma torch.

[0022] A simpler provision of gaseous fluids or a simpler volume flow control of the control units of these gaseous fluids can be achieved if, according to a variant of the invention, it is provided that the first connection for gaseous fluids and the second connection for gaseous fluids and / or other connections for gaseous fluids are fluidly connected to a gas supply device, in particular from a common gas supply device.

[0023] According to a variant, the first gaseous fluid connection and the second gaseous fluid connection and / or other gaseous fluid connections may be supplied with the same composition of gas from a gas supply device, which may simplify the regulation of the individual fluid flows in the plasma generation element.

[0024] According to a variant of the invention, at least one fresh gas supply and at least one circulation gas supply can be provided into a gas supply device for providing at least a portion of at least one of the gaseous fluids, and the circulation gas supply can be connected to an apparatus for thermally treating a substance, in particular a furnace, into which the hot fluid generated by the plasma generating element can be introduced. By circulating the exhaust gas from the apparatus for thermally treating a substance, the energy balance of the device for generating plasma, and thus of the above-mentioned apparatus, can be improved. Furthermore, the consumption of fresh gas can be significantly reduced.

[0025] According to a variant of the invention, it can be provided that at least one transfer element for the circulating gas is arranged in the circulating gas supply. In this way, an overpressure can be achieved in the circulating gas flow. The circulating gas supplied at overpressure to the gaseous fluid supply to the plasma generating element and subsequently to the device for thermally treating substances can prevent the ingress of oxygen-containing gases from the device's environment and thus also prevent oxidation problems in the device for thermally treating substances.

[0026] According to another variant of the invention, the plasma generating element may have a connection for an ignition gas, which on the one hand can simplify the ignition of the plasma and on the other hand can also expand the range of gaseous fluids that can be used in the device to provide the plasma.

[0027] According to another variant of the invention, it can be provided that at least one heat exchanger is arranged in the fresh gas supply for heating the newly supplied gaseous fluid. This heat exchanger can further improve the energy balance of the device, in particular to avoid excessive cooling of the circulating gas. The heat for heating the fresh gas can come, for example, from a residual gas stream that is withdrawn from the system and introduced, for example, into an exhaust stack.

[0028] To further improve the energy yield, according to a variant of the invention, the inside of the first flow channel and / or the inside of the second flow channel can be at least partially provided with a reflective coating, thereby achieving a re-reflection of the thermal energy radiated towards the wall towards the hot fluid flow, which also provides better protection of the plasma generating elements against overheating.

[0029] According to a variant, it can be provided that the reflective coating is arranged in the form of strips or rows or screws, by configuring the coating in this way it is easier to avoid a decrease in the efficiency of the inductive energy supply into the gaseous fluid.

[0030] According to another variant of the invention, it can be provided that several plasma generating elements are arranged, which makes it possible to introduce energy over a larger area and / or achieve a higher power for thermal treatment of the substance. Thus, according to a variant of the method, several plasma generating elements can be used, in which case the thermal energy to be introduced into the gaseous fluid is controlled and / or regulated by controlling the power of at least one of the plasma generating elements.

[0031] However, according to a variant, this embodiment can also be designed so that the plasma generating elements have different power outputs. This allows the plasma generating device to be more easily adapted to different processes, for example by operating one of the plasma generating elements, particularly one operated with a lower power output, in the range of 0% to 100%, and the remaining plasma generating elements at full power. This also allows the energy balance of the device to be improved.

[0032] A variant of the device can be provided in which a possible receiving space is arranged in the treatment chamber for the substance, the receiving space being fluidly connected to the exhaust gas conduit, and in which at least one flap and / or at least one slider and / or at least one cross-section narrowing element is arranged in the exhaust gas conduit, which allows for easy adjustment of the pressure around the plasma-generating element, which means that additional adjustments in the treatment chamber can be omitted if necessary.

[0033] In order to increase the radiation rate in the treatment chamber of the device for thermal treatment of substances, according to another variant of the device, it can be provided that the treatment chamber and / or the device for providing plasma has a supply device for introducing solid particles that increase thermal radiation.

[0034] According to a variant of the method, it can be provided that the plasma is generated inductively using at least one electric induction coil, and further that the temperature of the induction coil and / or the temperature rise of the cooling liquid for the induction coil and / or the temperature change of the wall of the plasma generating element in the region of the hot gas outlet or plasma gas outlet are measured, and that the volumetric flow rate of the central gas stream is changed based on these measurements when a temperature change occurs. By shifting the pre-set volumetric flow rate ratio of the protective gas stream to the central gas stream in favor of the central gas stream, the efficiency of the device for generating plasma can be improved.

[0035] To further simplify the control of the device for generating plasma, a variant of the method can be provided in which the temperature of the protective gas flow is measured and, in the event of a temperature change, the volumetric flow rate of the protective gas flow is changed based on this measurement, and / or the gas pressure in the plasma-generating element is adjusted via a change in the volumetric flow rate in the exhaust gas conduit from the treatment chamber for thermally treating the substance. In the latter variant, the residual gas flow drawn off from the system can be minimized.

[0036] To regulate the temperature in the device, a variant can be provided in which the temperature of the central gas stream is calculated and, in the event of a temperature change, the volumetric flow rates of at least one of the supplied gases, in particular the central gas stream, are changed based on this calculation, which makes it easier to take the central gas stream into account without having to make major design changes to the plasma generating elements.

[0037] For a better understanding of the invention, it will now be explained in more detail with the aid of the following figures.

[0038] Each of these shows a simplified schematic diagram. [Brief explanation of the drawings]

[0039] [Figure 1] FIG. 1 shows a device for heat treating materials. [Figure 2] FIG. 2 shows part of a device for providing a plasma. [Figure 3] FIG. 3 shows details of a variant of the device for providing the plasma. [Figure 4] FIG. 4 shows part of another variation of a device for providing plasma. [Figure 5] FIG. 5 shows part of another variation of a device for providing plasma. [Figure 6] FIG. 6 shows an arrangement of multiple plasma generating elements. [Figure 7] FIG. 7 shows another arrangement of multiple plasma-generating elements. [Figure 8] FIG. 8 shows a jet pump in longitudinal section. [Figure 9] FIG. 9 shows some variations of the device for providing the plasma. [Figure 10] FIG. 10 shows a variant of a device for heat treating materials. [Figure 11] FIG. 11 shows another variant of a device for heat treating materials. DETAILED DESCRIPTION OF THE INVENTION

[0040] It should be noted at the outset that in the various embodiments described, the same parts are given the same reference numerals or the same component names, and in this case the disclosure contained in the entire description can be transferred by analogy to the same parts having the same reference numerals or the same component names. In addition, the positional details selected in the description, such as upper, lower, side, etc., directly relate to the description and the illustrated figures, and these positional details are transferred to new positions accordingly when a positional change occurs.

[0041] In the following, a first gaseous fluid, a second gaseous fluid, and other gaseous fluids are described. These fluids may be different gases or the same gas. Furthermore, the gaseous fluids may be pure gases or gas mixtures.

[0042] Furthermore, the terms fresh gas, circulating gas, exhaust gas and process gas (also called plasma gas) are also used below. Fresh gas and process gas can be formed by at least one of the gaseous fluids listed in the preceding paragraph. Circulating gas, as the name suggests, is circulated in the device according to the invention and used again for plasma generation. It therefore goes from exhaust gas back to process gas.

[0043] The terms "hot fluid" or "hot fluid stream" are also used herein for purposes of explanation, both for the plasma stream that is directed at the material to be treated, and for the hot gas stream, i.e., a gas stream that is heated using a plasma and then directed at or used to thermally treat the material to be treated.

[0044] The gaseous fluid may be any gas suitable for forming a plasma, such as nitrogen, argon, neon, xenon, air, carbon dioxide, carbon monoxide, hydrogen, gaseous water, or a mixture of at least two of these gases.

[0045] FIG. 1 shows a device 1 for heat-treating a substance 2 (hereinafter simply referred to as device 1).

[0046] The substance 2 may be a liquid or a gas, but preferably the substance 2 is a solid, in particular a metallic solid.

[0047] The heat treatment may be melting material 2 or controlling the temperature of material 2, such as maintaining material 2 at a predetermined temperature or heating material 2, although heat treatment may also include chemical reactions carried out at elevated temperatures. This list of possible uses for device 2 is intended to be exemplary only, with melting metallic solids being one preferred application.

[0048] Since the application areas of the device 1 are varied, the schematic representation of FIG. 1 should not be understood as limiting but merely as an illustration of the invention.

[0049] The device 1 has a receiving space 3 for the substance 2. The receiving space 3 may be formed by a separate container in which the substance 2 is placed, although in the case of gases or generally the receiving space 3 may simply be the housing 4 of the treatment chamber 5 or the chamber of the treatment chamber 5 in which the substance 2 for thermal treatment is placed. The above-mentioned separate container, if present, is also placed in the treatment chamber 5.

[0050] For the sake of completeness, it should be noted that more than one storage space 3 for a substance 2 may be arranged in the processing chamber 5, in which case different substances 2 may be stored in the storage spaces 3, for example to carry out chemical reactions.

[0051] The apparatus 1 further comprises a device 6 for providing plasma (hereinafter simply referred to as device 6), by means of which thermal energy for thermally treating the substance 2 is provided. This device 6 is arranged on the housing 4 of the treatment chamber 5 so that the plasma torch, or the plasma flow, or the hot gas flow 7 generated by the plasma from the process gas, extends into or towards the treatment chamber 5.

[0052] For other components of the device 1 not mentioned or described below, please refer to the relevant prior art to avoid repetition.

[0053] The device 6 comprises at least one plasma-generating element 8 .

[0054] A variant of the plasma generating element 8 (also called plasma torch) is shown in longitudinal section in FIG.

[0055] The plasma generating element 8 has an element body 9 (also called a torch body). Arranged on or in the element body 9 is at least one electrical induction coil 10 for plasma generation. Multiple induction coils 10 can also be used, in which case they can be configured to be adjustable and / or controllable independently of one another. The multiple induction coils 10 can be arranged one behind the other in the direction of fluid flow.

[0056] The plasma may be generated in other ways, for example by a magnetron, or more commonly by using microwaves (e.g., generated using a solid-state microwave generator), or by two electrodes.

[0057] Furthermore, a first flow passage 11 for a first gaseous fluid and a concentrically arranged second flow passage 12 for a second gaseous fluid are arranged within the element 9. The first flow passage 11 is at least partially arranged within the second flow passage 12, for example, in a region above the induction coil 10 or in a partial region thereof. The first and second flow passages 11, 11 may be tubular, for example, having a circular cross section. The first and / or second flow passages 11, 11 may be formed from a quartz glass tube, an aluminum oxide tube, a boron nitride tube, or the like.

[0058] The second flow path 12 can be arranged at a distance 13 from a surface 14 of the element body 9 (particularly the surface 9 behind which the induction coil 10 is located), the distance 13 being selected from the range of 0 mm to 30 mm, particularly from the range of 0 mm to 20 mm.

[0059] The first flow passage 11 can be arranged at a radial distance 15 from the second flow passage 12, the distance 15 being selected in the range of 0.1 mm to 40 mm, in particular 0.4 mm to 30 mm, and in particular the speed of the protective gas flow 20 can be adjusted via this distance.

[0060] The first flow path 11 has a first connection 16, i.e. a first supply, for a first gaseous fluid, and the second flow path 12 has a second connection 17, i.e. a second supply, for a second gaseous fluid. As can be seen from Figure 2, the first and second connections 16, 17 can be fed from a common supply conduit 18 for the gaseous fluid. However, there can also be completely separate / independent supplies for the first and second gaseous fluids.

[0061] A first gaseous fluid is fed via a first connection 16 into the first flow path 11 and forms a heated gas flow (central gas flow 19). A second gaseous fluid is fed via a second connection 17 into the second flow path 12 and forms a protective volume flow (protective gas flow 20) between the surface 14 of the plasma generating element 8, i.e., the element body 9, and the heated gas flow or plasma flow. Both gas flows, i.e., the central gas flow 19 and the protective gas flow 20, leave the plasma generating element 8 together via an outlet 21, i.e., an outlet opening, and are available for the thermal treatment of the substance 2.

[0062] It should be noted that the illustration of the plasma-generating element 8 in Figure 2 is for illustrative purposes only. The specific arrangement of the individual elements within the plasma-generating element 8 may be configured differently, as long as functionality is maintained.

[0063] In Figure 3, another embodiment, possibly an independent embodiment, of the plasma generating element 8 is shown diagrammatically in longitudinal section, again with the same reference symbols or component names used for parts that are the same as in Figures 1 and 2. To avoid unnecessary repetition, reference is made to the above description.

[0064] 3, the first flow path 11 terminates at a distance from the outlet 21 of the plasma generating element 8, which may improve the effect of the induction coil 10, particularly on the central gas flow 19. The specific distance to the outlet 21 depends on the respective design of the plasma generating element 8.

[0065] It can further be seen that no separate channel element (tube) is used for the second flow path 12 and that, according to the variant of the plasma generating element 8, the second flow path 12 is bounded externally by the surface 14 of the body 9 of the plasma generating element 8, i.e., is formed by the plasma generating element 8 itself. Alternatively, as in the variant according to FIG. 2 and shown by dashed lines in FIG. 3, it can be provided that the second flow path 12 is formed by a separate channel element 22, which is arranged directly adjacent to the surface 14 of the body 9. If necessary, this channel element 22 can be formed as a coating on the surface 14 of the body 9. This coating can be made, for example, at least partially of silver, gold, aluminum, etc. Of course, also in the embodiment of the plasma generating element 8 according to FIG. 3, the remote arrangement of the channel element 22 shown in FIG. 2 is conceivable.

[0066] Figure 3 also shows that the induction coil 10 can be arranged at a small distance from the surface 14 of the element body 9. Figure 3 further shows that the induction coil 10 can be cooled, for which purpose the induction coil 10 can have cooling passages 23. The cooling medium that can flow through the cooling passages 23 can be, for example, water, cooling oil, etc.

[0067] In a variant of the plasma generating element 8 according to Fig. 3, it is provided that at least one further flow path 24 is arranged or configured within the plasma generating element 8. For example, the further flow path 24 can be configured within the element body 9 of the plasma generating element 8. The further flow path 24 is fluidly connected to a further connection 25 for a further gaseous fluid. If necessary, the further connection 25 can also be connected to the supply passage 18 (see Fig. 2), so that all three gaseous fluids have the same composition. However, it is also conceivable to supply the further gaseous fluid completely independently of the first and second gaseous fluids.

[0068] As can be seen from Figure 3, the other flow paths 24 are configured to run at an angle relative to the first flow path 11 and the second flow path 12, and the angle 26 between the flow paths 11 or 12 and 24 is configured so that the flow direction of the gas flow formed by the third fluid, in particular the cooling gas flow 27, runs towards the centre or longitudinal central axis 28.

[0069] In Figure 3, the other flow passages 24 run at the same angle of inclination over the entire length of the plasma generating element 8, i.e. the element body 9. However, it may also be provided that only the end section is configured to run at an angle which is angle 26. This end section begins at the outlet opening 29 of the other flow passages 24 in the plasma generating element 8. Thus, the other flow passages 24 may be configured to have different angles of inclination over their length or may have a curved shape.

[0070] Further flow paths 24 allow the supply of other gaseous fluids to change the temperature of the hot gas flow 7 or the plasma flow formed by the protective gas flow 20 and the central gas flow 19. Also, the position of the hot gas flow 7 or the plasma flow or the plasma torch may be changed if necessary.

[0071] According to a preferred variant of the plasma-generating element 8, the angle 26 that at least the end section of the further flow channel 24 makes with the first and second flow channels 11, 12 may be selected from the range of 10° to 80°, in particular from the range of 15° to 70°. For example, the angle 26 may be 20°, 30°, 40°, 45°, 50° or 60°.

[0072] It is conceivable within the scope of the present invention to provide a single other flow channel 24. As shown in Fig. 4, which shows a cross-sectional plan view of part of a variant of the plasma generation element 8, it is also possible to provide a plurality of flow channels 24, for example four, or only two or three, or more than four, for example five or six, flow channels 24. The plurality of other flow channels 24 are distributed around the circumference defined by the second flow channel 12, in particular evenly or symmetrically. Between the individual other flow channels 24, webs 30 of the element body 9 can be provided.

[0073] It should be noted here that the second flow path 12 may be divided into a plurality of second flow paths 12 that are distributed around the circumference of the first flow path 11 .

[0074] As shown in Fig. 4, the plurality of further flow channels 24 each extend over an annular segment (or annular section). According to variants of the plasma generation element 8, the annular segment can be selected from the range of 2° to 88°. For example, the annular segment can extend over the range of 10° to 80° or the range of 20° to 70°. However, a single annular segment may also extend over the range of 10° to 358°. In general, the annular segment can extend over a range from 2° to a value determined by 360° / number of annular segments - 1°, in particular 360° / number of annular segments - 5°.

[0075] The ring segments may all have the same circumferential length, although at least one of the ring segments may have a different circumferential length than the other ring segments.

[0076] As can be seen from Fig. 1, according to another variant of the device 6, it is conceivable that this device 6 comprises a gas supply device 31. As indicated by the dashed lines in Fig. 1, it is conceivable that the plasma generation element 8 is supplied not only with a first gaseous fluid but also with a second gaseous fluid and further gaseous fluids from the gas supply device 31. For this purpose, the connection 16 for the first gaseous fluid and the connection 17 for the second gaseous fluid and / or further connections 25 for further gaseous fluids may be in fluid communication with the gas supply device 31.

[0077] However, it is also contemplated that some or each of the connections 16 , 17 and 25 may be in fluid communication with a separate gas supply 31 .

[0078] Thus, the first connection 16 for the first gaseous fluid, the connection 17 for the second gaseous fluid, and the other connections 25 for the other gaseous fluids may each be supplied with the same gaseous fluid, or at least two of them, or all of them, may be supplied with different gaseous fluids. For example, the first connection 16 may be supplied with fresh gas, and the second connection 17 and / or the other connections 25 may be supplied with circulating gas. Thus, according to another variant of the device 6, as shown by the dashed lines in FIG. 1, it may be provided that at least one fresh gas supply 32 and at least one circulating gas supply 33 open to a gas supply device 31 for providing at least a portion of at least one of the gaseous fluids. The circulating gas supply may be connected to the apparatus 1 for heat-treating the substance 2, in particular to a furnace, into which the hot gas or plasma generated by the plasma-generating element 8 can be introduced.

[0079] According to another variant of the device 6, it can be provided that the circulating gas is introduced directly into the plasma generating element 8 without detouring via the gas supply device 31, as shown by the solid line in FIG.

[0080] According to another variant of the device 6, it can be provided that at least one transfer element 34 for the circulating gas, for example a jet pump, is arranged in the circulating gas supply. With regard to the transfer element 34, see also the description below.

[0081] According to another variant of the device 6, it can be provided that the plasma generating element 8 has a connection 35 for an ignition gas 36, for example for argon, thereby improving or promoting the generation of plasma, or that the plasma is provided by feeding a smaller amount of a suitable gas into the device 6.

[0082] According to a variant of the device 6, it may also be provided that at least one heat exchanger 37 is arranged in the fresh gas supply 32 for heating the freshly supplied gaseous fluid (fresh gas). This heat exchanger may be constructed in accordance with the state of the art.

[0083] It should be noted here that in Figure 1 the fresh gas supply 32 is connected to the gas supply device 31. However, alternatively or additionally it may be provided that the fresh gas supply 32 is connected directly to the plasma generating element 8, as indicated by the dashed line in Figure 1.

[0084] In Figure 5, another, possibly independent, embodiment of the plasma generating element 8 is shown diagrammatically in longitudinal section, again with the same reference symbols or component names used for parts that are the same as in Figures 1 to 4. To avoid unnecessary repetition, reference is made to the above description.

[0085] In this variant of the device 6 or the plasma-generating element 8, it may be provided that the first and / or second flow channels 11 and / or 12 have a reflective coating 38 on the inside. This coating 38 may extend over the entire length of the first and / or second flow channels 12 or over only a portion of their length, for example, only in the initial or terminal and / or central regions of the first and / or second flow channels 11 and / or 12. The coating 38 may consist of sections with different compositions, thereby better adapting to the temperature distribution within the plasma-generating element 8. This is because radiation maxima appear at different wavelengths depending on the temperature. That is, at higher temperatures, the radiation maxima shift to shorter wavelengths. In this way, materials for the coating sections that are particularly effective for the respective radiation maxima can be selected according to the respective wavelength or wavelength range. For example, at shorter wavelengths, a coating made of aluminum is more effective than a coating made of gold or silver. At longer wavelengths, the opposite may be true.

[0086] The coating 38 may have, for example, a metallic composition. For example, the coating 38 may be made of silver, gold, platinum, aluminum, or an alloy comprising at least one of these metals. This makes it possible, in particular, to adjust, change, or enhance the quality and / or wavelength range of the reflected radiation. In particular, alloys or alloy elements may be used to cover a wavelength range of reflected radiation below 500 nm or below 200 nm, thereby increasing the proportion of reflected radiation within this wavelength range.

[0087] In addition to the coating 38 being formed over the entire circumference, it is also conceivable to form the coating in strips or rows, as suggested by the dashed strips 39 in Fig. 5. The strips 39 may have a width in the circumferential direction of the first flow channel 11 or the second flow channel 12 selected from the range of 0.1% to 20% of the circumference of the first flow channel 11 or the second flow channel 12, in particular a width selected from the range of 1% to 10%.

[0088] The strips 39 can be arranged relative to one another at a distance 40 selected from the range between 0.1% and 20% of the circumference of the first flow path 11 or the second flow path, in particular at a distance 40 selected from the range between 1% and 10%.

[0089] Furthermore, it can be provided that only partial regions of the circumference or the entire circumference are provided with spaced apart strips 39 of the first flow channels 11 or the second flow channels 12 .

[0090] The strips 39 may all be made of the same material, although they may also be made of different materials, for example strips 39 made of metals with different reflectivity may be combined with one another within the plasma generating element 8. Also, as mentioned above, the strips may be partially made of different materials, so that the continuous coating 38 is provided with different materials.

[0091] The strip 39 has a longitudinal extension in the direction of the longitudinal central axis 28 through the first flow channel 11. In a variant, the strip shape of the coating 38 can be obtained by one or more spiral configurations, which can also be configured with a distance between the coated sections (e.g. in the form of a spiral, uncoated section).

[0092] The strips 39 can be configured as a coating 38, although they can also be manufactured as separate components and subsequently joined to the first flow channel 11 or the second flow channel 12. The same applies to the coating 38 itself, which is then formed as a tube that is inserted into the first flow channel 11 or the second flow channel 12. It is furthermore conceivable that the first flow channel 11 or the second flow channel is made from a correspondingly reflective material or is made to have a correspondingly reflective surface, for example by means of a configured surface structure.

[0093] Figures 6 and 7 show, in a schematic and partial view, other, possibly independent, embodiments of device 6, where again the same reference numerals or component names are used for parts that are the same as in Figures 1 to 5. To avoid unnecessary repetition, reference is made to the above description.

[0094] In the preceding description of the device 6, the device always has only one plasma generating element 8. However, it is also conceivable that several plasma generating elements 8 are arranged in the device 6. For this reason, Figures 6 and 7 show variants with three or five plasma generating elements 8 by way of example. Also, only two, four or more than five, for example six, plasma generating elements 8 may be arranged in the device 6.

[0095] The plasma generating elements 8 may all have the same heating power, or may have different heating powers, as suggested by the different sizes of the plasma generating elements 8 in Figures 6 and 7. It should again be noted that the specific illustrations should be understood as examples only. Other embodiments are possible, such as an embodiment with three plasma generating elements 8 having the same heating power, or an embodiment with one plasma generating element 8 and a plasma generating element 8 with a smaller heating power, for example, where the "smaller" plasma generating element 8 can be used to compensate for peak loads.

[0096] For example, if three plasma generating elements 8 each have a maximum output of 300 kW (three power supplies to the gaseous fluid are used), and an output of 900 kW is desired, the plasma generating elements 8 can be operated at 100% output (300 kW each), or if an output of 700 kW is desired, the plasma generating elements 8 can be operated at 78% output each, or if an output of 600 kW is desired, two plasma generating elements 8 can be operated at 100% output while the third plasma generating element is operated at 0% output, or if an output of 300 kW is desired, one plasma generating element 8 can be operated at 100% output and the other two at 0% output. If the maximum load is 400 kW, it can be provided that two plasma generating elements 8 are operated at 100% output and one plasma generating element 8 is operated at 25% output. At a maximum load of 400 kW, it may be provided that two plasma generating elements 8 are operated at 0% and one plasma generating element 8 at 25% power to obtain a desired power output of 100 kW.

[0097] It should be noted that these examples are for illustrative purposes only and are not limiting in nature.

[0098] The multiple plasma generating elements 8 may all be configured in the same way, so this description of the plasma generating elements 8 may apply to all plasma generating elements 8 herein.

[0099] According to a variant of the device 1, the treatment chamber 5 can be connected to an exhaust gas conduit 41 in which at least one flap 42 and / or at least one slider and / or at least one cross-sectional narrowing element 43 is arranged. The cross-sectional narrowing element 43 can be configured, for example, as an orifice, possibly as an orifice with a through-hole of varying diameter.

[0100] By means of at least one flap 42 or at least one slider or at least one cross-sectional narrowing element 43, it is possible to control or adjust the volumetric flow rate of the exhaust gas leaving the device 1 via an exhaust element 44, which is, for example, a chimney.

[0101] The remainder of the exhaust gas becomes cycle gas and can be fed back into the process, for example, via the cycle gas line 32. The part leaving the device 1 through the discharge element 44 can be exchanged for fresh gas via the fresh gas supply 33. It is therefore possible to control and / or adjust the volumetric flow ratio of cycle gas / fresh gas by means of the at least one flap 42 and / or the at least one slider and / or the at least one cross-sectional constriction element 43. It is also possible to adjust the pressure in the treatment chamber 5.

[0102] According to another variant of the device 1, also shown in Fig. 1, it can be provided that the treatment chamber 5 and / or the device for providing a plasma 6 has a feeder 45 for introducing solid particles that enhance thermal radiation. This feeder 45 can be, for example, a nozzle, which can finely distribute and feed the solid particles into the treatment chamber 5, or into the plasma generating element 8, or generally into the device 6. The feeder 45 can also have other configurations.

[0103] The solid particles can be made of graphite, metal, for example iron, copper, aluminum, etc. Also, the solid particles can be used to react with the substance 2 in the processing chamber 5, for example to form an alloy. The solid particles can have an average particle size thickness, for example, between 0.1 μm and 1000 μm.

[0104] The device 6 can be used to provide a plasma capable of heating a gas flow, whereby the resulting hot gas flow 7, or the plasma flow itself, can be used for the thermal treatment of the substance 2. For this purpose, a gaseous fluid is introduced into at least one plasma generating element 8 of the device 6, and a plasma is generated in the plasma generating element 8. To improve protection of the plasma generating element 8, it is provided that the gaseous fluid in the plasma generating element 8 is guided in the form of a central gas flow 19 surrounded by a protective gas flow 20.

[0105] It may be provided that the gaseous fluid in the plasma generating element 8, formed from the protective gas flow 20 and the central gas flow 19, is mixed with another gaseous fluid, in which case the temperature and / or position of the torch flare can be adjusted or controlled using this other gaseous fluid.

[0106] In order to regulate and / or control the apparatus 1 or device 6, in particular the volumetric flow rate of the gaseous fluid, according to a variant, the temperature of the induction coil 10 and / or the temperature rise of the coolant flowing through the cooling passages 23 of the induction coil 10 and / or the temperature change of the wall of the plasma generating element 8 in the region of the hot gas or plasma gas outlet from the plasma generating element 8 are measured. This measurement can be used, for example, to vary the volumetric flow rate of the central gas stream 20 when a temperature change occurs.

[0107] The temperature may be measured by known methods, for example by means of at least one thermocouple arranged on or in the wall of the plasma generating element 8 in the region of the plasma gas outlet.

[0108] It is further conceivable that the temperature of the protective gas flow 20 is measured and that the volumetric flow rate of the inert gas 20 is changed based on this measurement when a temperature change occurs, and / or that the gas pressure in the plasma generating element 8 is controlled by changing the volumetric flow rate from the treatment chamber 5 in the exhaust gas conduit 41.

[0109] It is further conceivable to calculate the temperature of the central gas stream 19 and, in the event of a temperature change, use this calculated value to vary the volumetric flow rate of at least one of the gases supplied, in particular the volumetric flow rate of the central gas stream 19.

number

number

[0110] However, it is also possible to measure the temperature of the central gas stream 19, in particular to measure it contactlessly, for example using a pyrometer.

[0111] The features of the following embodiments may form an independent invention by themselves or in combination with the features of the preceding embodiments. In particular, for the variants of the device 6 or the apparatus 1 shown below, it is not necessarily necessary to divide the gaseous fluid into a central gas stream 19 and a protective gas stream 20.

[0112] This separate invention is a device 6 for providing plasma, comprising at least one plasma generating element 8 having at least one inlet 46 and an outlet 47 for a gaseous fluid. A first flow path 11 is arranged or configured in the plasma generating element 8, and optionally a second flow path 12 is arranged concentrically therewith and at least partially surrounding the first flow path 11, the first flow path 11 being fluidly connected to a first connection 16 for a gaseous fluid for forming a heated gas flow or a plasma flow. The at least one inlet 46 is formed by the connection 16 for a gaseous fluid. As mentioned above, and this is also a preferred variant of the device 6 or the plasma generating element 8, multiple gaseous fluids can be introduced into the plasma generating element 8, so that the plasma generating element 8 can have multiple inlets 46 through which other gaseous fluids can be introduced into the plasma generating element 8. See the above description.

[0113] In this variant, there is also present or arranged one or more gaseous fluid transfer elements 34. The one or more transfer elements 34 are in fluid communication with the inlet 46 of the plasma-generating element 8.

[0114] The following will discuss in detail a single transfer element 34. If multiple transfer elements 34 are present, the following description may also apply to multiple transfer elements 34, as some or all of the transfer elements 34 may have the same configuration.

[0115] The gaseous fluid transported by the transport element 34 can be or has been accelerated thereby.

[0116] According to a variant, the plasma generating element 8 can be in fluid communication with a gas supply 31, which can preferably have a fresh gas supply 32 and / or a circulating gas supply 33 for circulating gas. The above-mentioned explanations of these variants are applicable.

[0117] According to a variant, it can be provided that a transfer element 34 is arranged in the circulating gas flow for the circulating gas, which is fluidly connected to the outlet 47 of the plasma generation element 8. In the embodiment of the device 1 according to Fig. 1, the outlet of the plasma generation element 8 is not in direct fluid communication with the transfer element 34, with at least the treatment chamber 5 being arranged between them. Both variants are possible, i.e. the variant with direct fluid communication between the outlet 47 and the transfer element 34 and the variant with indirect fluid communication between the outlet 47 and the transfer element 34, but the latter variant is more preferred.

[0118] According to a preferred variant of the device 6, the transport element 34 may be a jet pump 48, as shown for example in FIG.

[0119] The jet pump 48 has a first gas connection 49, a fuel connection 50 and an outlet 51. The first gas connection 49 can be connected to the fresh gas supply 32 or preferably to a circulating gas supply (see FIG. 1 ) so as to accelerate the fresh or circulating gas, in particular coming from the exhaust gas of the treatment chamber 5.

[0120] The fuel connection 50 is supplied with fuel, in particular gaseous fuel, at overpressure, which is converted into velocity in the jet pump 48 by a cross-sectional constriction element 52 through which the fuel must pass. This generates a negative pressure in the first gas connection 49, which accelerates the gas supplied therein and moves with it.

[0121] In principle, any suitable fuel can be used, but gaseous fuel is preferred, although in a preferred variant of the device 6 fresh gas is used as fuel and is also supplied to the plasma generating element 8, so that in this variant the fuel connection 50 is connected to a fresh gas supply via a gas supply 31, for example as shown in FIG.

[0122] According to a variant, it can be provided that the volumetric flow rate of the circulation gas flow is regulated by means of the volumetric flow rate of fresh gas supplied to the jet pump 48. This can be done, for example, via a control element 52, which is arranged in the fresh gas supply to the jet pump, as can also be seen in Figure 1. The control element 52 can be, for example, a flap, a slider or a valve.

[0123] It should be noted that in general, the apparatus 1 or device 6 may have an adjusting and / or control device 53, to which corresponding data may be provided wirelessly or by wire by sensors of the apparatus 1 or device 6, and the adjusting and / or control device 53 may output corresponding adjusting and / or control signals, for example to vary the volumetric flow rate of the process gas.

[0124] Instead of or in addition to the control element 52, the volumetric flow rate can also be varied or controlled using a controllable jet pump 48. For this purpose, the controllable jet pump 48 can be configured with a control of the volumetric flow rate or flow rate of the fresh gas supplied to the jet pump 48 as fuel.

[0125] Figure 9 shows, in a schematic way, another, possibly independent, embodiment of a device 6 for providing a plasma. Again, the same reference numerals or component names are used for parts that are the same as in Figures 1 to 8. To avoid unnecessary repetition, reference is made to the above description.

[0126] In this variant, the inlet 46 of the plasma generating element 8 is in fluid communication with another fresh gas supply 32 .

[0127] According to another variant, a heat exchanger 54 is arranged upstream of the transport element 34 in the flow direction of the gaseous fluid, in particular the circulating gas.

[0128] Furthermore, according to a variant of the device 6, a further heat exchanger 55 is arranged in the other fresh gas supply 32.

[0129] The heat exchanger 54 and the other heat exchangers 55 may be constructed in accordance with the state of the art.

[0130] It is also conceivable that another heat exchanger 55 is in fluid communication with the heat exchanger 54 upstream of the transfer element 34. This allows the circulating gas in the heat exchanger 54 to be cooled and the thermal energy gained in the process to be transferred to the fresh gas supplied to the plasma-generating element 8 via another fresh gas supply 32.

[0131] Alternatively, the heat exchanger 54 in the circulating gas supply 33 may be connected to the heat exchanger 37 (see FIG. 1) of the device 1 for transferring thermal energy.

[0132] By cooling the circulating gas upstream of the conveying element 34, it is also possible to use a conveying element 34 that is less heat-resistant, in particular a fan or a turbine, for example according to a variant of the device 6.

[0133] Other transfer elements 34 that can be used include pumps, vacuum pumps, compressors, injectors, and the like.

[0134] According to a variant, at least one filter element can be arranged upstream of the transport element 34 in the flow direction in order to be able to supply a purer gas to the transport element 34. For example, the wear load or clogging of the transport element 34 and the plasma generation element 8 can be reduced or prevented.

[0135] The features of the following embodiments can form an independent invention by themselves or in combination with the features of the preceding embodiments. In particular for the following variants of the device 1, it is not necessarily necessary to split the gaseous fluid into a central gas stream 19 and a protective gas stream 20 and / or to use a transfer element 34.

[0136] Figures 10 and 11 show, in a schematic way, other, possibly independent, embodiments of the device 1. Again, the same reference symbols or component names are used for parts that are the same as in Figures 1 to 9. To avoid unnecessary repetition, reference is made to the above description.

[0137] In these variants, the apparatus 1 for thermally treating a substance 2 again comprises a treatment chamber 5 and at least one device 6 for providing plasma, the treatment chamber 5 having an inlet 56 for supplying a gaseous fluid to the treatment chamber 5 and an outlet 57 for discharging the gaseous fluid from the treatment chamber.

[0138] In both variations, the outlet 57 of the processing chamber 5 is fluidly connected to at least one heat exchanger 58 having an inlet 59 for supplying a gaseous fluid and an outlet 60 for discharging it.

[0139] Preferably, the gaseous fluid is exhaust gas from the treatment chamber 5 , which is circulated through the apparatus 1 .

[0140] The heat exchanger 58 comprises at least one heat storage element 61. The heat storage element 61 can be formed, for example, by a material based on or comprising aluminum oxide (Al2O3), silicon dioxide (SiO2), iron (III) oxide (Fe2O3), titanium dioxide (TiO2), potassium oxide (KO), calcium oxide (CaO), sodium oxide (Na2O), etc.

[0141] At least one heat storage element 61 serves to absorb heat from the gaseous fluid passed through the heat exchanger 58 and store it for later use.

[0142] In the variant shown in Fig. 10, at least one further heat exchanger 58 is provided, which also has at least one heat storage element 61. However, it is also possible to have only one heat exchanger 58 with at least one heat storage element 61. In this case, the energy extracted from the process gas and stored in the heat storage element 61 can be used, for example, for other processes. It is also possible to use the thermal energy extracted from the process gas during cooling as heating energy for space heating and / or water heating and / or electricity generation. For these variants, it can be provided that the at least one heat exchanger 58 is arranged in a fluid circuit that connects the outlet 57 of the treatment chamber 5 with the inlet 56 of the treatment chamber.

[0143] However, in a preferred variant, the gas added to the process gas, ie in this case the recycle gas, is reused in the process itself.

[0144] This is achieved in this variant of the device 1 by using at least two heat exchangers 58, each with at least one heat storage element 61. For this purpose, the hot circulating gas is fed through an outlet 57 into the first heat exchanger 58, which is the upper of the two heat exchangers 58 in the illustration of Figure 10. In this first heat exchanger 58, the circulating gas is cooled and the extracted thermal energy is stored in its heat storage element 61.

[0145] After the first heat exchanger 58, the cooled circulating gas is fed into a gas transfer element 62, such as a fan or one of the above-mentioned transfer elements 34. To this end, the outlet 60 of the first heat exchanger 58 may be fluidly connected to the gas transfer element 62, which may build up pressure and feed the circulating gas through the heat exchanger 68 or in a circuit.

[0146] According to a variant of the device 1, if the circulating gas is still too hot to be introduced into the gas transport element 62, it is possible to mix the circulating gas with cooler fresh gas upstream of the gas transport element 62. For example, this fresh gas may be injected into the cooled circulating gas. This fresh gas may be supplied, for example, via the gas supply device 31. In this variant, a supply element may be arranged in the device 1 upstream of the gas transport element 62 in the flow direction of the gaseous fluid, which supplies a cooling medium, such as fresh gas, into the gaseous fluid.

[0147] Generally, (pre-)cooling of the circulating gas may also take place at other locations. Furthermore, in order to avoid thermal overload of the heat storage element 61, a partial stream of the circulating gas can be branched off and, if necessary, fed to another cooling system with another heat exchanger. The separately cooled partial gas stream can be fed to the heat exchanger 58, i.e. to at least one heat storage element 61, where it is not heated but is (thermally) discharged.

[0148] According to another variant, it can alternatively or additionally be provided that cooler fresh gas is already introduced into the hot circulating gas stream upstream of or at the inlet 59. To that end, a fresh gas supply can be arranged at or upstream of the inlet 59 of the heat exchanger 58 for the gaseous fluid.

[0149] Gas transfer element 62 may also be located at other locations in device 1 .

[0150] After the first heat exchanger 58, the cooled circulating gas enters the second (lower) heat exchanger 58 via inlet 59, preferably by means of a gas transfer element 61. The inlet 59 of the second heat exchanger 58 is connected to the outlet 60 of the first heat exchanger 58, either directly or indirectly via the gas transfer element 61.

[0151] Since at least one heat storage element 61 of the second heat exchanger 58 is already heated during normal operation, i.e. not during the start-up phase of the device 1, the circulating gas is heated again in this second heat exchanger 58. This causes the heat storage element 61 of the second heat exchanger 58 to cool.

[0152] The heated circulating gas is supplied again as process gas through the outlet 60 of the second heat exchanger 58, which is in fluid communication with the inlet 56 of the processing chamber via the plasma generating element 8. Prior to this, the process gas is heated to the desired processing temperature in the plasma generating element 8.

[0153] This process continues until first heat exchanger 58 reaches a critical temperature, which may be predetermined by, for example, the temperature tolerance of gas transport element 62.

[0154] At this point, the flow direction of the circulating gas is reversed. For this purpose, the position of the corresponding cycle flap 63 or other suitable element for changing the gas flow direction can be appropriately changed, so that the exhaust gas from the treatment chamber 5 is then first guided through the second (lower) heat exchanger 58 to be cooled, and then guided through the first (upper) heat exchanger 58 to be heated again. In other words, within this cycle, the second heat exchanger 58 becomes the first heat exchanger 58, and the first heat exchanger 58 becomes the second heat exchanger 58. The cycle is then carried out again until the critical temperature is reached again, and the cycle flap 63 changes its position again.

[0155] The corresponding wiring diagram for this cycling is shown in FIG.

[0156] The changing of the position of the cycle flap 63 or of the above-mentioned elements is preferably performed fully automatically, for which purpose a temperature sensor can be arranged in each of the heat exchangers 58, which provides a corresponding measurement signal.

[0157] According to another variant of the device 1 shown in FIG. 11, the heat exchanger 58 has a plurality of heat storage elements 61 arranged rotatably, so that the heat storage elements 61 can be acted on alternately by a gaseous fluid from the treatment chamber 5, in particular by hot exhaust gas or circulating gas.

[0158] Hot gas or hot exhaust gas (recycle gas) can be fed via the upper part of the heat exchanger 58, which transfers its heat to the heat storage elements 61, i.e., to each heat storage element 61 in its correct rotational position. The cooled exhaust gas (recycle gas) is then fed again as process gas to the plasma-generating element 8. The thermal energy reaches the lower part of the heat exchanger 58, which is also fixed, via the heat storage elements 61 and heats the cooler fresh air fed there. This heats up, the heat storage elements 61 are cooled again, and it is available for new loading.

[0159] This process can be controlled via a temperature sensor in the cold exhaust gas, for example via a thermocouple. The amount of heat stored per heat storage element 61 can be determined via the rotation speed of the heat exchanger 58.

[0160] The heated fresh gas may then be fed to the plasma generating element 8 .

[0161] In the illustration of Figure 11, eight heat storage elements 61 are provided, although fewer or more than eight heat storage elements 61 can also be used, for example three, or four, or five, or six, or seven, or nine, or ten, or even significantly more than eight, for example more than 100 heat storage elements 61.

[0162] The heat storage element 61 can be configured, for example, as a honeycomb body, as a spherical packing or as a packing in general, as a foam, or as an additively formed body. The permissible pressure loss, space requirements, etc. can be determined via its shape.

[0163] The heat storage element 61 may be provided with a coating, for example a catalytic coating.

[0164] Since the heat or thermal energy is preferably reused within the same process, in these variants it may be provided that at least one heat exchanger 58 is arranged in the fluid circuit, which at least one heat exchanger 58 connects the outlet 57 of the processing chamber 5 with the inlet 56 of the processing chamber 5.

[0165] According to another variant of the device, a third heat exchanger 64 can be arranged upstream of the gas transport element 62 in the flow direction, thereby allowing the gaseous fluid to be cooled again after it leaves the first heat exchanger 58. This third heat exchanger 64 can also be configured without a heat storage element 61.

[0166] In the above description, it has been assumed that the entire remaining volume flow is cooled, apart from the partial volume flow that is completely withdrawn from the process via the discharge element 44. However, it is also possible that only a portion of the remaining volume flow is cooled, in which case this portion can be used, for example, to cool components within the plasma-generating element 8.

[0167] The examples show possible modifications, and the individual modifications can also be combined with one another.

[0168] Finally, it should be noted that, as a matter of style, some elements are shown not to scale and / or in enlarged and / or reduced size to facilitate understanding of the structure. [Explanation of symbols]

[0169] 1 device 2 substances 3. Containment space 4. Housing 5 Processing Chamber 6 Devices 7. Hot Gas Flow 8 Plasma generating elements 9 Elements 10 induction coil 11 Flow path 12 Flow path 13 distance 14 Surface 15 distance 16 Connection 17 Connection 18 Supply conduit 19 Central Gas Flow 20 Protective gas flow 21 Exit 22 Passage Elements 23 Cooling passage 24 flow paths 25 Connection 26 angles 27 Cooling gas flow 28 Longitudinal central axis 29 Exit opening 30 Web 31 Gas supply equipment 32 Fresh gas supply unit 33 Circulating gas supply section 34 Transport Elements 35 Connection 36 Ignition gas 37 Heat exchanger 38 Coating 39 Strip 40 distance 41 Exhaust gas pipe 42 Flap 43 Cross-sectional constriction element 44 Emission factors 45 Feeding device 46 Entrance 47 Exit 48 Jet Pump 49 Gas connection 50 Fuel connection 51 Exit 52 Control Elements 53 Control device 54 Heat exchanger 55 Heat exchanger 56 Entrance 57 Exit 58 Heat exchanger 59 Entrance 60 exit 61 Heat storage element 62 Gas Transfer Element 63 Cycle Flap 64 Heat exchanger

Claims

1. 1. A device (6) for providing plasma, comprising at least one plasma generating element (8), on and / or within which at least one electric induction coil (10) and / or magnetron is arranged, and further within the plasma generating element a first flow path (11) and a second flow path (12) concentric therewith, the second flow path (12) at least partially surrounding the first flow path (11), the first flow path (11) being in fluid communication with a first connection (16) for a gaseous fluid to form a heated gas flow or a plasma flow, characterized in that the second flow path (12) is in fluid communication with a second connection (17) for a gaseous fluid to form a protective volume flow between a surface (14) of the plasma generating element (8) and the heated gas flow or plasma flow.

2. 2. The device (6) according to claim 1, characterized in that the second flow path (12) is formed by the plasma generating element (8) itself.

3. 3. The device (6) according to claim 1 or 2, characterized in that at least one other flow channel (24) is arranged in the plasma generating element (8), which is fluidly connected to another connection (25) for another gaseous fluid, and which is arranged so that the other flow channel (24) extends obliquely to the first flow channel (11), at least in an end section facing the first flow channel (11), and by supplying the other gaseous fluid via the at least one other flow channel (24), the temperature of the hot gas flow and / or the plasma flow formed from the protective gas flow (20) and the central gas flow (19) can be changed.

4. 4. The device (6) according to claim 3, characterized in that at least the end section of the other flow path (24) has an angle (26) with the first flow path (11) selected from the range of 5° to 80°.

5. 5. A device (6) according to claim 3 or 4, characterized in that a plurality of other flow paths (24), in particular four other flow paths (24), are distributed along the circumference defined by the second flow path (12).

6. A device (6) according to claim 5, characterized in that each of said other flow paths (24) extends over a circular segment selected from the range of 2° to 88°.

7. 7. The device (6) according to any one of claims 3 to 6, characterized in that the first connection (16) for a gaseous fluid and the second connection (17) for a gaseous fluid and / or the further connection (25) for a gaseous fluid are in fluid communication with a gas supply (31), in particular from a common gas supply (31).

8. 8. The device (6) according to claim 7, characterized in that the first connection (16) for gaseous fluid and the second connection (17) for gaseous fluid and / or the other connection (25) for gaseous fluid are supplied with gas of the same composition from the gas supply device (31).

9. 9. The device (6) according to claim 7 or 8, characterized in that at least one fresh gas supply (32) and at least one circulation gas supply (33) open into the gas supply device (31) for providing at least a part of at least one of the gaseous fluids, the circulation gas supply (33) being connectable to an apparatus (1) for heat treatment of a substance (2), in particular to a furnace, into which the hot fluid generated by the plasma generating element (8) can be introduced.

10. 10. The device (6) according to claim 9, characterized in that at least one transfer element (34) for circulating gas is arranged in the circulating gas supply (33).

11. 11. The device (6) according to any one of claims 1 to 10, characterized in that the plasma generating element (8) has a connection (35) for an ignition gas (36).

12. 12. The device (6) according to any one of claims 1 to 11, characterized in that in the fresh gas supply (32) at least one heat exchanger (37) is arranged for heating the freshly supplied gaseous fluid.

13. 13. The device (6) according to any one of claims 1 to 12, characterized in that the inside of the first flow path (11) and / or the inside of the second flow path (12) are at least partially provided with a reflective coating (38).

14. 14. The device (6) according to claim 13, characterized in that the reflective coating (38) is arranged in the form of strips or rows or screws.

15. 15. The device (6) according to any one of claims 1 to 14, characterized in that a plurality of plasma generating elements (8) are arranged.

16. 16. The device (6) according to claim 15, characterized in that the plasma generating elements (8) have different power outputs.

17. 17. An apparatus (1) for the thermal treatment of a substance (2), in particular a solid, comprising at least one device (6) for providing a plasma, characterized in that the device (6) for providing a plasma is formed according to any one of claims 1 to 16.

18. 18. The device (1) according to claim 17, characterized in that a possibly existing receiving space (3) is arranged in the treatment chamber (5) for the substance (2), the receiving space being fluidly connected to an exhaust gas conduit (41), and in the exhaust gas conduit (41) at least one flap (42) and / or at least one slider and / or at least one cross-sectional narrowing element (43) is arranged.

19. 19. Apparatus (1) according to claim 17 or 18, characterized in that the treatment chamber (5) and / or the device (6) for providing plasma comprises a feeder (45) for introducing solid particles that enhance thermal radiation.

20. 1. A method of operating a device (6) for providing a plasma for thermally treating a material (2), said method comprising: providing a gaseous fluid in at least one plasma generating element (8) of said device (6); generating a plasma in the plasma generating element (8); providing a high-temperature fluid flow by heating the gaseous fluid with the plasma, optionally to form a high-temperature gas, and directing the high-temperature fluid flow onto the material to be treated (2) outside the plasma generating element (8); A method comprising:

10. A method according to claim 9, characterized in that the gaseous fluid is guided in the plasma generating element (8) in the form of a central gas flow (19) surrounded by a protective gas flow (20).

21. 21. The method according to claim 20, characterized in that a further gaseous fluid is added to the gaseous fluid formed in the plasma generating element (8) from the protective gas flow (20) and the central gas flow (19).

22. 22. The method of claim 21, wherein the temperature and / or the position of the plasma torch is adjusted or controlled by means of said other gaseous fluid.

23. 23. The method according to claim 20, wherein the plasma is generated inductively by means of at least one electric induction coil, and further comprising measuring the temperature of the induction coil and / or the temperature rise of a coolant for the induction coil and / or the temperature change of the walls of the plasma generating element in the region of the hot gas outlet or plasma gas outlet, and varying the volumetric flow rate of the central gas stream in the event of a temperature change based on these measurements.

24. 24. The method according to any one of claims 20 to 23, characterized in that a plurality of plasma generating elements (8) are used and the thermal energy introduced into the gaseous fluid is controlled and / or regulated by controlling the power of at least one of the plasma generating elements (8).

25. 25. The method according to claim 20, wherein the temperature of the protective gas flow is measured and, in the event of a temperature change, the volumetric flow rate of the protective gas flow is changed based on this measurement.

26. 26. The method according to any one of claims 20 to 25, characterized in that the gas pressure in the plasma generating element (8) is adjusted via a change in the volume flow rate in an exhaust gas conduit (41) from a treatment chamber (5) for thermally treating the material (2).

27. 27. The method according to claim 20, wherein the temperature of the central gas stream (19) is calculated and, in the event of a temperature change, at least one volumetric flow rate of the supplied gas, in particular the volumetric flow rate of the central gas stream (19), is changed based on this calculated value.

Images