INDUCTION HEATING APPARATUS, SYSTEM, PRODUCTION LINE, METHOD, AND USE

Abstract

The present invention relates to an induction heating device for heating metal articles, the induction heating device comprising a plurality of at least two resonant circuits for generating respective magnetic fields for heating the metal articles, and an energy supply device for supplying electrical energy to the resonant circuits, the energy supply device having a circuit breaker for connecting the induction heating device to a power supply and at least one inverter for converting a direct current into an alternating current for the energy supply of the resonant circuits, the energy supply device having a switching device, the switching device being designed to enable at least indirect energy coupling between the circuit breaker and the resonant circuits, the number of resonant circuits which can be simultaneously energy coupled being less than the number of resonant circuits of the induction heating device.

Description

[Technical field]

[0001] The present invention relates to induction heating devices, systems, production lines, methods and uses. [Background technology]

[0002] A production line for manufacturing and / or processing semi-finished and / or primary products and / or intermediate products and / or finished products made of ferrous, steel and / or non-ferrous materials consists of a number of devices in which the primary products and / or intermediate products and / or finished products, respectively, pass through one or more steps. The devices can be, for example, heating or cooling devices, conveying devices, forming devices, cleaning devices, chemical processing devices, surface coating devices, cutting or joining devices and combinations thereof. The steps can be, for example, temperature raising and lowering, conveying, deformation processing, cleaning, chemical processing, surface coating, cutting or joining and combinations thereof.

[0003] The temperature increase of the primary and / or intermediate products and / or finished products is a prerequisite and essential step for many processes. For this purpose, induction heating devices, among others, can be used. These induction heating devices can be used at various points in the production line.

[0004] In induction heating with induction heating devices, an inductor is excited to oscillate, especially in the medium frequency range, and it is known to incorporate this inductor into a so-called resonant circuit with the aid of an additional capacitor, which is excited by an inverter, for example by means of a bridge circuit, a half-bridge circuit or a single switch, by switching on a voltage pulse near the resonant frequency of the resonant circuit.

[0005] Typically for this purpose, a supply voltage, for example a single-phase or multiphase AC voltage, is first rectified and smoothed, and a DC voltage is supplied to an inverter, which excites an inductor. Summary of the Invention [Problem to be solved by the invention]

[0006] The problem on which the invention is based is to provide an improvement or alternative to the state of the art. [Means for solving the problem]

[0007] According to a first aspect of the invention, the object is achieved by providing an induction heating device for heating metal products, in particular semi-finished products and / or primary products and / or intermediate products and / or finished products made of ferrous, steel and / or non-ferrous metal materials, comprising: a plurality of at least two resonant circuits, in particular three, four, five, six or more resonant circuits, for generating respective magnetic fields for heating the metal article; an energy supply device for supplying electrical energy to the resonant circuit, A circuit breaker to connect the induction heating device to the power supply and In an induction heating device having at least one inverter, in particular two, three, four, five, six or more inverters, which converts a direct current into an alternating current for the energy supply of a resonant circuit, The problem is solved by an induction heating device in which the energy supply device has a switching device, which is designed to enable at least indirect energy coupling between the circuit breaker and the resonant circuit, and in which the number of resonant circuits to which energy can be coupled at the same time is less than the number of resonant circuits of the induction heating device.

[0008] In this regard, the following terms are explained.

[0009] It is expressly pointed out at the outset that within the scope of this patent application, indefinite articles and numerical indications such as "one", "two", etc. are generally to be understood as "minimal" indications, i.e. "at least one", "at least two", etc., unless it is clear from the respective context or obvious to a person skilled in the art or technically necessary that they can only mean "exactly one", "exactly two", etc.

[0010] Within the scope of this patent application, the expression "in particular" is always to be understood as introducing optional and preferred features, and should not be understood in the sense of "and" and "i.e."

[0011] By "induction heating device" is understood a device that is set up to inductively heat a metal article using electrical energy. An induction device (Induktionsvorrichtung) uses at least one "resonant circuit" each having at least one coil to generate an alternating magnetic field caused by the coil. If the metal article is connected to the alternating magnetic field, a voltage is induced in the metal article by the alternating magnetic field, which generates a current in the metal article, in particular an alternating current. This current, which can also be called an eddy current since it always flows in a closed circuit, heats the metal article by Joule losses. In addition, in the case of ferromagnetic metal articles, heating occurs as a result of remagnetization losses, even up to the Curie temperature, at which the ferromagnetic or ferroelectric properties of the metal article completely disappear.

[0012] Advantageously, the metal article can be heated directly by the induction heating device because the heat is generated within the metal article itself and does not have to be introduced to the surface of the metal article from an external source by thermal conduction, convection, and / or radiation.

[0013] By "metallic goods" is meant any product comprising electrically conductive ferrous, steel and / or non-ferrous metallic materials. In particular, a metallic goods may be understood as any semi-finished product and / or any primary product and / or any intermediate product and / or finished product that is electrically conductive.

[0014] The coil of the induction heating device may have less than one full turn, one full turn, and / or more than one full turn, in particular two or more turns, three or more turns, or four or more turns.

[0015] The operative connection between the metal article and the alternating magnetic field can be provided by longitudinal magnetic field induction and / or transverse magnetic field induction. In longitudinal magnetic field induction, the magnetic field lines extend substantially in the longitudinal extension direction of the metal article. In transverse magnetic field induction, the magnetic field lines in the metal article extend substantially in the transverse extension direction of the metal article, in particular in the thickness direction and / or width direction of the metal article. If the metal article is a sheet metal, in transverse magnetic field induction the magnetic field lines can enter the sheet metal substantially in the thickness direction of the sheet metal and exit again in the thickness direction.

[0016] By "energy supply device" is understood a device that is arranged to provide electrical energy for the operation of at least one resonant circuit, in particular at a current of a suitable current intensity, at a suitable voltage and / or at a suitable frequency. The energy supply device can be designed to provide electrical energy to a number of resonant circuits, in particular at least two resonant circuits, three, four, five, six or more resonant circuits.

[0017] The energy supply device may be designed to make available and provide electrical energy for provision to the resonant circuit for optimal efficiency operation of the resonant circuit, particularly at an optimal frequency and / or optimal phase position relative to the phase position of the resonant circuit.

[0018] The energy supply may be designed to prevent or reduce any effects on the power supply that may be caused by operation of the resonant circuit.

[0019] The energy supply device is designed to be connected to a power supply, which may be understood as a three-phase power supply network. The power supply may be an AC or DC power supply.

[0020] The power supply can have a medium voltage or a high voltage.

[0021] The high voltage may be 36 kV or more, preferably 60 kV or more, and particularly preferably 100 kV or more. Furthermore, the high voltage may be 150 kV or more, preferably 200 kV or more, and particularly preferably 300 kV or more. The high voltage may be 400 kV or less. Furthermore, the high voltage may be 300 kV or less, preferably 200 kV or less, and particularly preferably 150 kV or less.

[0022] The medium voltage can be an alternating current of 1 kV or more, or a direct current of 1.5 kV or more, preferably 2 kV or more, particularly preferably 10 kV or more. The medium voltage can be 15 kV or more, preferably 20 kV or more, particularly preferably 30 kV or more. The medium voltage can be 36 kV or less. Furthermore, the medium voltage can be 30 kV or less, preferably 20 kV or less, particularly preferably 15 kV or less.

[0023] Preferably, the voltage levels may be defined in accordance with IEC 60519-4.

[0024] A "circuit breaker" is a switching element that is set to close an electric circuit or to switch it off, especially for service and / or maintenance work or for operational interruptions. Circuit breakers can be designed as power switches for high currents.

[0025] Optionally, the energy supply device includes a single phase circuit breaker or a three phase circuit breaker.

[0026] The circuit breaker proposed here makes it possible to ensure that the energy supply device can be switched voltage-free.

[0027] Preferably, in the open position the circuit breaker connects the energy supply device to ground potential, which provides increased safety against electric shock.

[0028] An "inverter" is a power electronic device or electrical circuit configured to convert direct current (DC) to alternating current (AC). The resulting AC frequency depends on the inverter's switching algorithm.

[0029] The inverter circuit can be controlled by applying a pulse width modulation algorithm.

[0030] In particular, the inverter can be designed to operate a specific resonant circuit. When using different resonant circuits, it is advantageous to use different inverters tailored to the different resonant circuits, and similarly, rectifiers and / or smoothing circuits and / or transformers and / or circuit breakers can be designed for a number of different resonant circuits.

[0031] By "switching device" is understood an assembly designed to switch an electrically conductive connection by means of a switch, ie to make or break an electrically conductive connection between at least two contacts.

[0032] The switching device can be designed to switch an alternating current and correspondingly can be arranged between the inverter and the at least one resonant circuit.

[0033] The switching device can be designed to switch a direct current and correspondingly can be arranged between a rectifier or a smoothing circuit or a direct current source and at least one resonant circuit.

[0034] The switching device preferably has a plurality of switching possibilities between a current source, preferably an AC or DC current source, and at least two consumers, preferably three, four, five or more consumers, in particular a resonant circuit and / or an inverter. The switching device can be designed to break or make exactly one connection between the current source and exactly one of the consumers, or to switch to another consumer. The switching device can be designed to break, make or switch two, three, four or more connections between exactly one current source and two, three, four or more consumers, in particular to switch in pairs.

[0035] The switching device can be designed to include multiple current sources and can connect, disconnect or switch exactly one current source to one consumer or to multiple consumers, respectively. Preferably, the switching device is designed such that it is possible to simultaneously form less than one connection between a consumer and at least two current sources.

[0036] Here, an energy supply device for an induction heating device is proposed which comprises a circuit breaker, at least two inverters and a switching device, the circuit breaker being configured to connect the energy supply device to a power source, the inverters being configured to convert direct current into alternating current for the energy supply of a resonant circuit, the switching device being designed to enable at least indirect energy coupling between the circuit breaker and a plurality of resonant circuits, the number of resonant circuits which can be simultaneously energy coupled being less than the number of resonant circuits which can be at least indirectly connected to the switching device.

[0037] The energy supply device allows at least one component of the energy supply device to be used alternately and / or intermittently for multiple resonant circuits, where multiple resonant circuits cannot be operated simultaneously. In other words, certain components of the energy supply device, in particular circuit breakers, are installed only as necessary for a reasonable simultaneous operation of the installed / installable resonant circuits, whereas the resonant circuits can be installed anywhere in the production line where heating may be required.

[0038] Alternatively, an induction heating device is proposed here which comprises an energy supply device as described above and at least two resonant circuits.

[0039] Thus, different resonant circuits can be operated alternately and / or intermittently at different points in the production line using common components of the energy supply device designed to operate only some or one of the available resonant circuits.

[0040] The energy supply device accounts for a large part of the investment cost of an induction heating device. By using the energy supply device proposed in this specification, the investment cost of an induction heating device, in particular an induction heating device with spatially distributed resonant circuits, can be reduced.

[0041] In many cases, not all resonant circuits in a production line are operated at the same time. The resonant circuits are currently operated primarily depending on the product that is currently to be manufactured. Thus, a total of six resonant circuits are installed in the production line, but in each case there may be up to three resonant circuits operating simultaneously. If each induction heating device then contains all the components of the energy supply device, the associated investment costs would be significant.

[0042] Modern production lines must be flexible to accommodate the manufacture of a wide range of metal products, each with its own requirements regarding temperature control during the process to be carried out, where each most advantageous operation of the production line may require the use of resonant circuits at various points within the production line depending on the product, the previous and next products produced, the current energy price mix, and other boundary conditions.

[0043] The energy supply device proposed in this specification makes it possible to increase the flexibility of the production line, shorten the reaction time when changing products, improve the energy efficiency of the production line in possible operating modes and metal products, and reduce the structural length of the production line.

[0044] Optionally, a circuit breaker is configured to connect the induction heating device to a DC power source.

[0045] In this case, it is proposed that the circuit breaker of the energy supply device is arranged to be connected to a DC power source, preferably a DC power source having a medium or low voltage.

[0046] The inverters of the energy supply devices can be designed in such a way that they can be indirectly connected to a DC power source, ie preferably capable of supplying a medium-voltage or low-voltage DC voltage.

[0047] The low voltage can be 120 V or more, preferably 220 V or more, and particularly preferably 240 V or more. The low voltage can be 1,000 V or less, and particularly preferably 900 V or less. The low voltage can be 600 V or less, preferably 240 V or less, and particularly preferably 220 V or less.

[0048] Optionally, the circuit breaker is configured to connect the induction heating device to an AC power source, and the energy supply device comprises at least one rectifier, in particular 2, 3, 4, 5, 6 or more rectifiers, between the circuit breaker and the at least one inverter for converting AC current into DC current for the energy supply of the at least one inverter.

[0049] In this regard, the following terms are explained.

[0050] A "rectifier" is an electrical device that converts alternating current, which periodically changes direction, into direct current.

[0051] The rectifier may be a three-phase rectifier. The rectifier may be designed to provide a medium or low voltage.

[0052] The rectifier may have a topology including and / or consisting of diodes. The three-phase rectifier may be an uncontrolled n×6 pulse diode rectifier, in particular a 6 pulse diode rectifier, a 12 pulse diode rectifier, an 18 pulse diode rectifier, etc.

[0053] The use of transistors and / or thyristors allows the rectifier to be advantageously controlled in an open or closed loop, which makes it possible to meet the requirement of connecting the energy supply to a static var compensator in order to comply with the regulations of the power supplier.

[0054] Expediently, the energy supply device comprises a transformer between the circuit breaker and the at least one rectifier.

[0055] In this regard, the following terms are explained.

[0056] A "transformer" is a component that transfers electrical energy from one electrical circuit to another without having a conductive connection between the two electrical circuits. A transformer converts alternating current (AC) on the primary side of the transformer into alternating current on the secondary side of the transformer.

[0057] The transformer may be a three-phase transformer.

[0058] The transformer can be a high voltage to medium voltage transformer that converts a high voltage on a primary side of the transformer to a medium voltage on a secondary side of the transformer.

[0059] The transformer can be a high voltage to low voltage transformer that converts a high voltage on a primary side of the transformer to a low voltage on a secondary side of the transformer.

[0060] The transformer can be a medium voltage to low voltage transformer that converts a medium voltage on a primary side of the transformer to a low voltage on a secondary side of the transformer.

[0061] Optionally, the circuit breaker is designed as a medium voltage switching device.

[0062] In this regard, the following terms are explained.

[0063] By "medium voltage switching installation" is understood a central assembly of power circuit breakers and / or fuses and / or protective switches serving to protect and / or control and / or earth the energy supply equipment.

[0064] According to a preferred embodiment, the at least one inverter and / or the at least one rectifier are designed for medium voltage operation, in other words the at least one rectifier and / or the at least one inverter are designed to supply a medium voltage.

[0065] Preferably, the energy supply device comprises a smoothing circuit between the circuit breaker and the at least one inverter, in particular between the at least one rectifier and the at least one inverter.

[0066] In this regard, the following terms are explained.

[0067] The derivation of a DC voltage in a power supply, in particular in an energy supply device, from an AC source can result in ripple voltages, particularly when using diode rectifiers. Ripple voltages are periodic residual fluctuations in the output voltage of the rectifier.

[0068] To smooth out the ripple voltage, the rectifier can be connected to a "smoothing circuit" that is configured to smooth out the ripple voltage.

[0069] The smoothing circuit may include a capacitor connected in parallel with the rectifier circuit.

[0070] The smoothing circuit may include an inductor connected in series with the rectifier circuit.

[0071] According to an expedient embodiment, the rectifier and the inverter can be energy-coupled to one another by means of a DC rail.

[0072] According to an optional embodiment, the energy supply device comprises a DC converter between the circuit breaker and the at least one inverter, in particular between the at least one rectifier and the at least one inverter.

[0073] In this regard, the following terms are explained.

[0074] A "DC converter" is a power electronic device or electrical circuit configured to convert direct current (DC) present at the input of a DC converter to a higher, lower, or inverted voltage level direct current at the output of the DC converter, depending on the voltage supplied to the input.

[0075] A DC converter arranged between the rectifier and the inverter can change the voltage level between the rectifier and the inverter. In this way, in particular, a medium voltage rectifier can be combined with a low voltage inverter. This can increase the overall efficiency of the energy supply system.

[0076] Preferably, the switching device is disposed between the rectifier and the at least two inverters, and the switching device is To create an energy coupling between the rectifier and exactly one inverter, and / or Forming an energy coupling between the rectifier and the group of inverters, in particular between the rectifier and a part of the group of inverters It is designed to be:

[0077] Alternatively, in the case of induction heating devices already supplied with DC voltage, in particular capable of being connected to a local DC voltage grid, it can be provided that a switching device is arranged between the circuit breaker and the at least two inverters, the switching device being Energy coupling between the circuit breaker and exactly one inverter, and / or It is designed to create an energy coupling between the circuit breaker and a group of inverters, in particular between the circuit breaker and a part of the group of inverters.

[0078] The switching device proposed in this specification is arranged between a rectifier or a circuit breaker and at least two inverters, whereby the switching device is designed for switching in the region of a DC transmission line.

[0079] Advantageously, it can be achieved that the components of the energy supply device, which are integrated between the power supply of the induction heating device and the switching device, do not have to be designed separately for each resonant circuit to be supplied. Instead, it is sufficient that the components integrated before the switching device are integrated only once in terms of their number, and then the components each only have to be adapted to the power of the induction heating device that is simultaneously provided in the maximum specified state. Since it is now provided that at least one resonant circuit of the induction heating device can be operated less than those arranged on the entire induction heating device, the rated power of the components up to the switching device, in particular the rated power of the circuit breaker and / or the transformer and / or the rectifier, can also be correspondingly smaller and in comparison with the sum of the rated powers of all the integrated resonant circuits. Alternatively, the rated power that can be provided by the energy supply device can also be provided by several individual components, in particular components connected in parallel with each other. In particular, several transformers and / or several rectifiers can be connected in parallel before the switching device without departing from the aspects proposed herein. The parallel-connected components can then each be designed in such a way that they can provide a part of the rated power that is required.

[0080] Thus, the induction heating device may have at least one rectifier and / or transformer and / or circuit breaker less than the resonant circuit.

[0081] Regarding the possible switching states of the switching devices proposed herein, the switching devices can be designed such that from a number of resonant circuits connected to a single switching device, up to just one resonant circuit can be energetically coupled to the DC terminals of the switching device at the same time, and correspondingly, a majority of the resonant circuits connected to the switching device can be operated alternately and / or intermittently.

[0082] Alternatively, with regard to the possible switching states of the switching device proposed herein, it can be provided that the switching device is designed to be able to form an energy coupling between the DC terminals of the switching device and the group of inverters, in particular between the DC terminals of the switching device and a part of the group of inverters, and in this case, it is also provided that at least one resonant circuit can be operated less simultaneously compared to the total number of resonant circuits incorporated. In that case, it can be provided that one switching connection can be switched alternately or intermittently, respectively, or multiple switching connections can be switched alternately and / or intermittently simultaneously, in particular a pair of resonant circuits can be switched simultaneously, in particular a first pair of resonant circuits can be switched simultaneously with a second pair of resonant circuits.

[0083] In particular, a first pair of resonant circuits arranged in a front region of the production line can be operated alternately or intermittently with a second pair of resonant circuits arranged in a rear region of the production line.

[0084] Expediently, a switching device is arranged between the inverter and the at least two resonant circuits, the switching device being To create an energy coupling between the inverter and exactly one resonant circuit to generate a magnetic field, and / or To generate each magnetic field, an energy coupling is generated between the inverter and the group of resonant circuits, in particular between the inverter and a part of the group of resonant circuits. It is designed.

[0085] The switching device proposed here is arranged between the inverter and the at least two resonant circuits, whereby the switching device is designed to switch in the region of the AC power transmission line.

[0086] Advantageously, it can be achieved that it is not necessary to design the components of the energy supply device separately for each resonant circuit to be supplied, but rather they can be dimensioned according to the maximum rated power that can be drawn at once and / or simultaneously by the resonant circuit, with parallel connection of the individual components also being conceivable in order to achieve the required rated power.

[0087] Thus, the induction heating device may have at least one rectifier and / or inverter and / or transformer and / or circuit breaker that is less than the resonant circuit. Furthermore, the induction heating device may have a rated power that can be provided by the energy supply device that is less than the sum of the rated powers of the resonant circuits included in the induction heating device.

[0088] Of course, the induction heating device may have multiple switching devices.

[0089] In particular, the induction heating device can have at least two switching devices between at least one circuit breaker and a number of inverters each at least indirectly connected thereto, and most of the switching devices can also be connected in parallel and can be designed to be connected to exactly one circuit breaker and / or exactly one transformer and / or exactly one rectifier.

[0090] The induction heating device may have at least two switching devices between at least one inverter and a number of resonant circuits at least indirectly connected to each other having the same electrical characteristics, and it may also be designed so that most of the switching devices can be connected in parallel with each other and can be connected to exactly one inverter and / or exactly one transformer and / or exactly one rectifier.

[0091] Further, the induction heating apparatus may be contemplated to have both one or more switching devices between the at least one circuit breaker and at least one respective inverter, and one or more switching devices between the at least one inverter and at least one respective resonant circuit.

[0092] It is also conceivable to operate several resonant circuits in parallel with one inverter, in which case it is advantageous if most of the resonant circuits have the same electrical characteristics.

[0093] Preferably, the induction heating device is designed to be mechanically movable and / or is at least partially designed to be mechanically movable.

[0094] In this regard, the following terms are explained.

[0095] By "mechanically movable" it is understood that the unit, in particular the induction heating device or energy supply device, is detachably connected to the ground for which it is designated and installed, the unit is provided with sling means for attaching the unit to a crane or the like, and / or the unit is supplied with electric current and / or working substance, in particular coolant, by detachable connection means.

[0096] This allows the induction heating device to be used flexibly at different points in the production line and minimizes the time required for refitting the production line. By means of a sling means it can be achieved that the induction heating device can be moved by a crane, a forklift and / or other dedicated moving devices.

[0097] According to an advantageous embodiment, a single resonant circuit can be designed to be portable, so that it can be used alternately at different points in a production line.

[0098] According to an expedient embodiment, the energy supply device is designed to be mechanically movable and / or is at least partially designed to be mechanically movable.

[0099] The parts of the energy supply device can in particular be power electronic components of the energy supply device, in particular a transformer, a rectifier, a DC converter, an inverter and / or a smoothing circuit.

[0100] Optionally, the resonant circuit is designed for longitudinal magnetic field induction and / or transverse magnetic field induction.

[0101] In this regard, the following terms are explained.

[0102] A resonant circuit designed for "longitudinal magnetic field induction" may have a coil surrounding at least one edge, preferably at least two edges, particularly preferably four edges, of a metal article.

[0103] Preferably, a resonant circuit designed for longitudinal magnetic field induction has several windings, preferably at least two windings, preferably at least three windings, particularly preferably at least four windings, of a coil wound transversely to the designated longitudinal extension of the metal article, the majority of the windings being preferably arranged compactly next to each other and the shortest distance between two adjacent windings being preferably smaller than the transverse extension of one winding.

[0104] A resonant circuit designed for "transverse magnetic field induction" has a coil that extends primarily in one plane, preferably in a meandering manner in one plane, and preferably does not surround the edges of the metal article.

[0105] Preferably, the resonant circuit designed for "transverse magnetic field induction" comprises a first coil and a second coil, each of which extends mainly in one plane, preferably each of which extends in a meandering manner in one plane, and preferably each of which does not surround either end of the metal article. The respective planes of extension may be arranged parallel to each other. The coils may be arranged in mirror symmetry with respect to each other. Preferably, the metal article to be heated passes between the coils, preferably in a mirror plane.

[0106] A coil assembly designed in this way, consisting of a first, substantially planar extending coil and a second, mirror-symmetric extending coil, can also be used for longitudinal magnetic field induction, if each coil forms a separate resonant circuit and these resonant circuits are operated with opposite clocks, i.e. the phase angle of the respective operating currents is preferably 180 degrees.

[0107] Advantageously, the resonant circuits designed for transverse magnetic field induction and the resonant circuits designed for longitudinal magnetic field induction can be operated in at least partially identical energy supply devices, which reduces the investment costs of the production line. In particular, the circuit breakers, rectifiers and smoothing circuits can be used in the same way and without modification for the resonant circuits designed for transverse magnetic field induction and for the resonant circuits designed for longitudinal magnetic field induction. In principle, the inverters of the energy supply devices can also be the same, whereby different operating modes can possibly be selected for the inverters and / or different control and / or regulating signals, in particular different pulse-width modulated signals, can be used.

[0108] Expediently, the electrical connection between the inverter and the resonant circuit is formed by means of a fluid-cooled busbar, in particular a busbar designed for internal cooling by means of a fluid.

[0109] Preferably, the busbars between the inverter and the resonant circuit can be cooled with a liquid coolant, in particular water, which can preferably be guided within and preferably through the busbars, in this way the busbars can be cooled, in particular by forced convection.

[0110] Alternatively, the busbars can be cooled using a gaseous coolant, in particular air or a mixture of different gases, whereby the busbars can be cooled using both forced and / or free convection.

[0111] According to a second aspect of the present invention, the above object is achieved by a system comprising a plurality of induction heating devices according to the first aspect of the present invention.

[0112] Needless to say, the above-mentioned advantages of the induction heating apparatus according to the first aspect of the invention are directly applicable to a system comprising a plurality of induction heating apparatus according to the first aspect of the invention.

[0113] It is expressly pointed out that the subject matter of the second aspect may be advantageously combined with the subject matter of the above aspects of the invention, both individually and / or cumulatively in any combination.

[0114] According to a third aspect of the present invention, the above mentioned problem is solved by a production line for producing and / or processing semi-finished and / or primary and / or intermediate and / or finished products made of metal articles, in particular ferrous, steel and / or non-ferrous metal materials, comprising an induction heating device according to the first aspect of the present invention and / or a system according to the second aspect of the present invention.

[0115] Needless to say, the above-mentioned advantages of the induction heating apparatus according to the first aspect of the invention and / or the system according to the second aspect of the invention can be directly applied to a production line comprising an induction heating apparatus according to the first aspect of the invention and / or a system according to the second aspect of the invention for manufacturing and / or processing metal articles, in particular semi-finished and / or primary and / or intermediate products and / or finished products made of ferrous, steel and / or non-ferrous metallic materials.

[0116] The production line may in particular be a hot rolling line using warm or high heat, and / or a belt conveyor installation.

[0117] It is expressly mentioned that the subject matter of the third aspect may be advantageously combined with the subject matter of the preceding aspects of the invention, either individually or cumulatively in any combination.

[0118] According to a fourth aspect of the present invention, the above problem is solved by a method of operating an induction heating apparatus according to the first aspect of the present invention, wherein at least two resonant circuits are operated alternately and / or intermittently at various points in the production line.

[0119] Needless to say, the above-mentioned advantages of the induction heating apparatus according to the first aspect of the invention are directly applicable to a method of operating an induction heating apparatus according to the first aspect of the invention.

[0120] It is expressly mentioned that the subject matter of the fourth aspect may be advantageously combined with the subject matter of the above-mentioned aspects of the invention, either individually or cumulatively in any combination.

[0121] According to a fifth aspect of the present invention, the above mentioned object is achieved by the use of an induction heating device according to the first aspect of the present invention for producing and / or processing a metal article, in particular a semi-finished product and / or primary product and / or intermediate product and / or finished product made of ferrous, steel and / or non-ferrous metallic material.

[0122] Needless to say, the above-mentioned advantages of the induction heating apparatus according to the first aspect of the invention are directly applicable to the use of the induction heating apparatus according to the first aspect of the invention.

[0123] It is expressly mentioned that the subject matter of the fifth aspect may be advantageously combined with the subject matter of the above aspects of the invention, either individually or cumulatively in any combination. Further advantages, details and features of the invention emerge from the examples described below. [Brief description of the drawings]

[0124] [Figure 1] FIG. 1 is a schematic diagram of a system including multiple induction heating devices according to the prior art. [Diagram 2] FIG. 1 is a schematic diagram of a first embodiment of a system of induction heating devices. [Diagram 3] FIG. 2 is a schematic diagram of a second embodiment of a system of induction heating devices. [Figure 4] 3 shows a schematic diagram of a third embodiment of a system consisting of an induction heating device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0125] In the following description, the same reference numerals denote the same components or features, so that the description of the components given in one figure is valid for the other figures and repetition of the description is avoided. Moreover, individual features described in connection with one embodiment can also be used separately in other embodiments.

[0126] The system 500 having a plurality of induction heating devices 100, in particular seven induction heating devices 100, according to the prior art of FIG. 1 for heating a metal article (not shown) essentially consists of a plurality of mutually independent induction heating devices 100 having no more than one direct operative connection with each other.

[0127] Basically, the induction heating device 100 comprises an energy supply device 20 and a resonant circuit 10 , the energy supply device 20 having at least one inverter 28 and a circuit breaker 22 .

[0128] Each induction heating device 100 has at least one circuit breaker 22, exactly one inverter 28, and exactly one resonant circuit 10 configured to generate a respective magnetic field for heating a metal article (not shown).

[0129] The circuit breaker 22 is configured to connect the induction heating device 100 to a power source (not shown).

[0130] The inverter 28 is configured to convert DC current to AC current for the energy supply of the resonant circuit 10 and is connected to the resonant circuit 10 by an AC transmission line 29 .

[0131] According to a first variant (not shown), the power supply (not shown) can be a DC power grid, in particular a medium-voltage DC power grid. According to this variant, the inverter 28 can be connected to the power supply by a DC power line 27, either directly via the circuit breaker 22 or indirectly via a DC converter (not shown) and the circuit breaker 22.

[0132] According to a second variant, the power supply can be an AC power supply, in particular a three-phase AC network. In this case, the energy supply device 20 comprises a rectifier 26 which can be directly connected to an inverter 28 by means of a DC transmission line 27 and / or a DC converter (not shown). Furthermore, the energy supply device 20 can comprise a transformer 24. The power supply (not shown) can in particular be a high-voltage or medium-voltage power supply, the transformer 24 being set to convert a high voltage into a medium or low voltage or to convert a medium voltage into a low voltage.

[0133] Most of the induction heating devices 100 in the system 500 can be arranged in a production line (not mentioned / not shown) for manufacturing / processing metal products, in particular semi-finished products and / or primary products and / or intermediate products and / or finished products, from ferrous, steel and / or non-ferrous materials, which production line can also have, besides the induction heating devices 100, processing devices 40 for processing metal products (not shown), which can be transported through the production line (not mentioned / not shown) in a preferred direction of movement 42. Depending on the position and rated power of the induction heating devices 100, it is then conceivable that the position of each resonant circuit 10 in the production line (not mentioned / not shown) will be different.

[0134] In contrast, the system 500 having a plurality of induction heating devices 100 in FIG. 2, in particular three induction heating devices 100, has a plurality of switching devices 30, in particular a number of switching devices 30 corresponding to the number of induction devices 100, in particular three switching devices 30, and the system has six resonant circuits 10 for heating metal articles (not shown).

[0135] Correspondingly, a system 500 having a plurality of induction heating devices 100 has a plurality of energy supply devices 20, in particular a number of energy supply devices 20 corresponding to the number of induction devices 100, in particular three energy supply devices 20.

[0136] According to the embodiment of FIG. 2, the switching devices 30 are each arranged in the region of an AC power transmission line 29 of the induction heating device 100 .

[0137] Each energy supply device 20 has at least one respective circuit breaker 22 and at least one respective inverter 28 , each inverter 28 being indirectly connected to at least two respective resonant circuits 10 via respective switching devices 30 .

[0138] Depending on the design of the power supply (not shown), the energy supply device 20 may also have a transformer 24 and / or a rectifier 26, which may be directly connected to the inverter 28 by a DC transmission line 27 and / or a DC converter (not shown).

[0139] Each switching device 30 comprises at least two switches 32 which make it possible to adjust the connection between the inverter 28 and a respective one of the resonant circuits 10 .

[0140] Many production lines (not shown) are equipped for various metal articles (not shown) to be manufactured and / or processed, whereby a certain flexibility in the production line is desired / given in terms of the amount and / or positioning of the technical equipment, in particular the induction heating devices 100. This however also leads to higher investment costs in the production line. The induction heating device 100 proposed here has a switching device 30 in the energy supply device 20, by means of which several resonant circuits can be supplied and / or operated alternately or intermittently or simultaneously by a common energy supply device 20, if the resonant circuits 10 have an electrically identical configuration. This allows a reduction in the necessary investment costs compared to the prior art.

[0141] Therefore, the induction heating device 100 proposed in this specification allows the number of resonant circuits 10 to which electrical energy can be alternately and / or intermittently or simultaneously provided by the energy supply device 20 to be greater than the number of energy supply devices 20.

[0142] 3 also comprises a number of switching devices 30, in particular a number of switching devices 30 corresponding to the number of induction devices 100, in particular three switching devices 30, so that the system has seven resonant circuits 10 for heating metal articles (not shown). In contrast to the embodiment according to FIG. 2, the switching devices 30 are here arranged in the region of the DC transmission line 27.

[0143] Correspondingly, an inverter 28 is respectively connected to each resonant circuit 10 by an AC power transmission line 29. This advantageously makes it possible to individually open-loop and / or closed-loop control each resonant circuit 10 via the individually assigned inverter 28.

[0144] Correspondingly, the number of resonant circuits 10 to which electrical energy can be provided alternately and / or intermittently or simultaneously by the energy supply device 20, equivalent to the number of inverters 28, can be greater than the number of rectifiers 26 and the number of circuit breakers 22 and / or transformers 24.

[0145] The system 500 having a plurality of induction heating devices 100, in particular two induction heating devices 100 in FIG. 4 also has a plurality of switching devices 30, in particular a number of switching devices 30 corresponding to the number of induction devices 100, in particular two switching devices 30, and the system has seven resonant circuits 10 for heating metal articles (not shown).

[0146] In that case, the first induction heating device 100 is designed in such a way that two resonant circuits 10 are arranged at the front end of a production line (not shown) and at the rear end of the production line, respectively. It should be borne in mind in particular that the resonant circuit 10 mounted at the front end can be operated in pairs with the resonant circuit 10 mounted at the rear end, alternately or intermittently. [Explanation of symbols]

[0147] 10 Resonant circuit 20 Energy supply device 22 Circuit Breaker 24 Transformers 26 Rectifier 27 DC Transmission Lines 28 Inverter 29 AC Transmission Lines 30 Switching Device 32 Switch 40 Processing equipment 42 Direction of movement 100 Induction heating device 500 Systems

Claims

1. An induction heating device (100) for heating metal products, in particular semi-finished and / or primary and / or intermediate and / or finished products made of ferrous, steel and / or non-ferrous metal materials, comprising: a plurality of at least two resonant circuits (10), in particular three, four, five, six or more resonant circuits (10), for generating respective magnetic fields for heating said metal article; an energy supply device (20) for supplying electrical energy to the resonant circuit (10), the energy supply device comprising: a circuit breaker (22) for connecting the induction heating device (100) to a power source; an induction heating device having at least one inverter (28), in particular two, three, four, five, six or more inverters (28), which convert a direct current into an alternating current for the energy supply of the resonant circuit (10), The induction heating device (100), characterized in that the energy supply device (20) has a switching device (30) designed to enable at least indirect energy coupling between the circuit breaker (22) and the resonant circuit (10), and the number of resonant circuits (10) that can be simultaneously energy coupled is less than the number of the resonant circuits (10) of the induction heating device (100).

2. The induction heating device (100) of claim 1, wherein the circuit breaker (22) is configured to connect the induction heating device (100) to a DC power source.

3. the circuit breaker (22) is configured to connect the induction heating device (100) to an AC power source; the energy supply device (20) comprises at least one rectifier (26) between the circuit breaker (22) and the at least two inverters (28) for converting an alternating current into a direct current for the energy supply of the at least one inverter (28), in particular two, three, four, five, six or more rectifiers (26); An induction heating device (100) according to claim 1, characterized in that

4. 4. The induction heating device (100) of claim 3, characterized in that the energy supply device (20) comprises a transformer (24) between the circuit breaker (22) and the at least one rectifier (26).

5. Induction heating device (100) according to any one of claims 1 to 4, characterized in that the circuit breaker (22) is designed as a medium voltage switching device.

6. Induction heating device (100) according to any one of claims 1 to 5, characterized in that the at least one inverter (28) and / or the at least one rectifier (26) are designed for medium voltage operation.

7. The induction heating device (100) according to any one of claims 1 to 6, characterized in that the energy supply device (20) has a smoothing circuit between the circuit breaker (22) and the at least one inverter (28), in particular between the at least one rectifier (26) and the at least one inverter (28).

8. The induction heating device (100) according to any one of claims 1 to 7, characterized in that the energy supply device (20) comprises a DC converter between the circuit breaker (22) and the at least one inverter (28), in particular between the at least one rectifier (26) and the at least one inverter (28).

9. A switching device (30) is disposed between the rectifier (26) and the at least two inverters (28), the switching device (30) comprising: to form an energy coupling between said rectifier (26) and exactly one inverter (28); and / or An induction heating device (100) according to any one of claims 1 to 8, characterized in that it is designed to create an energy coupling between the rectifier (26) and a group of inverters (28), in particular between the rectifier (26) and a part of the group of inverters (28).

10. A switching device (30) is disposed between the inverter (28) and the at least two resonant circuits (10), the switching device (30) comprising: to create an energy coupling between said inverter (28) and exactly one resonant circuit (10) in order to generate a magnetic field; and / or Induction heating device (100) according to any one of claims 1 to 9, characterized in that it is designed to create an energy coupling between the inverter (28) and a group of resonant circuits (10), in particular an energy coupling between the inverter (28) and a part of the group of resonant circuits (10), in order to generate a respective magnetic field.

11. The induction heating device (100) according to any one of claims 1 to 10, characterized in that the induction heating device (100) is designed to be mechanically movable and / or at least partially designed to be mechanically movable.

12. Induction heating device (100) according to any one of claims 1 to 11, characterized in that the energy supply device (20) is designed to be mechanically movable and / or at least partially designed to be mechanically movable.

13. Induction heating device (100) according to any one of the preceding claims, characterized in that the resonant circuit (10) is designed for longitudinal magnetic field induction and / or transverse magnetic field induction.

14. Induction heating device (100) according to any one of claims 1 to 13, characterized in that the electrical connection between the inverter (28) and the resonant circuit (10) is formed by a fluid-cooled busbar, in particular a busbar arranged for internal cooling by a fluid.

15. A system (500) comprising a plurality of induction heaters (100) according to any one of the preceding claims.

16. A production line for producing and / or processing metal articles, in particular semi-finished and / or primary and / or intermediate and / or finished products made of ferrous, steel and / or non-ferrous metal materials, comprising an induction heating device (100) according to any one of claims 1 to 14 and / or a system according to claim 15.

17. A method for operating an induction heating device (100) according to any one of claims 1 to 14, characterized in that at least two resonant circuits (10) are operated alternately and / or intermittently at various points in the production line.

18. Use of an induction heating device (100) according to any one of claims 1 to 14 for producing and / or processing metal articles, in particular semi-finished and / or primary and / or intermediate and / or finished products made of ferrous, steel and / or non-ferrous metallic materials.

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