US-12624896-B2 - Device for induction heating of at least one workpiece and method for induction heating of at least one workpiece

US12624896B2US 12624896 B2US12624896 B2US 12624896B2US-12624896-B2

Abstract

The invention relates to a device for inductively heating at least one workpiece, in particular a substantially strip-shaped workpiece, including at least one furnace housing; at least one inductor arrangement arranged within the furnace housing, the inductor arrangement being arranged at least partially in an inductor region of the furnace housing; at least one heating region for receiving process gas. The heating region being arranged within the furnace housing; and separating material for separating, in particular for thermally separating, the inductor region and the heating region. Furthermore, the invention relates to a method for inductively heating at least one workpiece.

Inventors

Stefan Dappen
Thomas Daube
Markus Langejürgen
Frank Maschler
Christian Vogt

Assignees

SMS ELOTHERM GMBH

Dates

Publication Date: 20260512
Application Date: 20230424
Priority Date: 20220429

Claims (7)

1 . A device for inductively heating at least one workpiece, comprising at least one furnace housing; at least one inductor arrangement arranged within the furnace housing, the inductor arrangement being arranged at least partially in an inductor region of the furnace housing; at least one heating region for receiving process gas, the heating region being arranged within the furnace housing; and separating material for thermally separating the inductor region and the heating region, wherein a thermal insulation is provided between the separating material and the heating region; wherein the separating material is designed in such a way that there is a fluidic connection between the inductor region and the heating region, wherein the separating material is designed as an at least partially permeable material for the fluidic connection between the inductor region and the heating region, and the permeable material is designed gas-permeable.
2 . The device according to claim 1 , wherein the separating material has at least one through-opening for the fluidic connection between the inductor region and the heating region.
3 . The device according to claim 1 , wherein the separating material comprises a fabric made of high-temperature fibers.
4 . A method for inductively heating at least one workpiece by means of a device according to claim 1 , comprising the following steps: guiding a workpiece to be heated along the at least one heating region of the furnace housing filled with process gas; heating the workpiece with the at least one inductor arrangement arranged in the inductor region; establishing a fluidic connection between the inductor region and the heating region with the separating material arranged between the inductor region and the heating region; and feeding a housing gas into the inductor region in such a way that there is a pressure gradient from the housing gas arranged in the inductor region towards the process gas arranged in the heating region.
5 . The method according to claim 4 , wherein before a workpiece to be heated is guided along the heating region of the furnace housing, the inductor region and the heating region are first purged by the housing gas; the process gas is then fed into the heating region; and additional housing gas is subsequently fed into the inductor region.
6 . The method according to claim 4 , wherein the housing gas fed into the inductor region has a dew point lower than a dew point of the process gas arranged in the process region, and/or the dew point of the housing gas arranged in the inductor region is monitored constantly and housing gas is fed as a function of the dew point.
7 . A method according to claim 4 , wherein the quantity of the housing gas to be fed in is determined as a function of the pressure difference existing between the inductor region and the heating region, and/or the quantity of the housing gas to be fed in is determined as a function of the housing gas volume flow occurring between the inductor region and the heating region, and/or the housing gas is fed into the inductor region in such a way that the temperature of the housing gas in the inductor region is lower than the temperature of the process gas in the heating region.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is the United States national phase of International Application No. PCT/EP2023/060577 filed Apr. 24, 2023, and claims priority to European Patent Application No. 22170873.8 filed Apr. 29, 2022, the disclosures of which are hereby incorporated by reference in their entireties. BACKGROUND OF THE INVENTION Field of the Invention The invention relates to a device for induction heating of at least one workpiece, in particular an essentially strip-shaped workpiece, comprising: at least one furnace housing; at least one inductor arrangement arranged within the furnace housing, the inductor arrangement being arranged at least partially in an inductor region of the furnace housing; at least one heating region for receiving process gas, the heating region being arranged within the furnace housing; and separating material for separating, in particular for thermal separation, the inductor region and the heating region. The invention also relates to a method for induction heating of at least one workpiece, in particular by means of an aforementioned device. Devices for induction heating are known from the prior art and can, for example, be referred to as continuous tunnel furnaces or electro-induction tunnel furnaces. Such devices can be used to inductively heat a workpiece. Induction heating processes are usually referred to as processes in which the surface of a material to be heated, in particular a steel material, is heated by means of an electromagnetic field induced in the workpiece. In such a process, the furnace tunnel can be filled with a process gas which should not escape from the furnace tunnel into an atmosphere surrounding the furnace tunnel. This is because if the process gas escapes from the furnace tunnel, not only can the air surrounding the continuous tunnel furnace be contaminated, but an explosive reaction of the process gas can also occur. Accordingly, conventional continuous tunnel furnaces usually have an essentially gas-tight furnace tunnel, which is connected to a gas-tight connection duct upstream and downstream of a heating section. An inductor arrangement can either enclose the workpiece or be arranged above and/or below the at least one workpiece. The problem with such an arrangement, however, is that the material usually used for gas-tight separation is at least partly made of metal, which would also heat up unacceptably when an inductor arrangement is used in the same way as the at least one workpiece. Description of Related Art EP 2 577 201 B1 discloses an electro-induction tunnel furnace having a gas-tight barrier chamber surrounding a gas-tight tunnel region, with a gas-tight separating plane or a gas-tight separating material being arranged between the tunnel region and the barrier chamber. In order to avoid an exchange of a barrier gas arranged in the barrier chamber and a process gas arranged in the tunnel region, the electro-induction tunnel furnace also has a barrier gas regulator. However, when providing such a gas-tight separating plane, the problem arises in practice that gas-tight materials are either metallic, i.e. problematic for the penetration of the magnetic field or such a penetration can only be realized with high energy losses, or can only be realized with a temperature-critical polymer material. Another disadvantage is that in the event of a high pressure difference between the barrier chamber and the tunnel region, large forces can act on the separating plane, whereby the forces can jeopardize the integrity of the separating plane. In addition, the gas-tight connection to a connecting duct can only be achieved with a high level of design effort. SUMMARY OF THE INVENTION Based on the aforementioned prior art, the present invention is thus based on the technical problem of providing a device and a method for induction heating of at least one workpiece, which enable reliable and safe operation of the device or reliable and safe operation of the method in a structurally simple manner. According to a first aspect of the present invention, the aforementioned technical problem is solved in an aforementioned device in that the separating material is designed in such a way that there is a fluidic connection between the inductor region and the heating region. By providing a fluidic connection between the inductor region and the heating region, a fluidic exchange of a medium arranged in the inductor region and a medium arranged in the heating region can be provided. In particular, the respective media are gases or gas mixtures that are located inside the furnace housing. For example, it has proven to be advantageous to flush the entire furnace housing with an inert housing gas, for example nitrogen or a nitrogen mixture, before starting operation of the device for induction heating of the at least one workpiece and then to fill it with the process gas used during operation of the aforementioned device, for example with h