Heating device

Abstract

The invention relates to a heating device (1), comprising at least one heating unit (3), which has a plurality of resistive heating elements, which are designed as plate-like elements (4).

Description

Technical Field

[0001] The present invention relates to a heating device comprising at least one heating unit, wherein the heating unit has a plurality of resistance heating elements.

[0002] The invention further relates to a heat treatment apparatus comprising a treatment chamber for an object to be treated and having a heating device at least partially arranged in the heat treatment apparatus. Background Art

[0003] Electrical heating of industrial furnaces using resistance heating is known. To do this, current flows through heating elements with corresponding resistance, releasing heat. Rod-shaped heating elements are often used for this purpose. In some furnace types, such as pusher furnaces, high energy density is required. Therefore, gas heating is often preferred for these furnaces. However, due to environmental concerns and the availability of gas, efforts are underway to replace gas heating with other heating systems whenever possible. Summary of the Invention

[0004] The object of the present invention is to provide a possibility for supplying a heat treatment installation with heating energy.

[0005] The object of the invention is achieved with the initially mentioned heating device in which the resistance heating element is designed as a plate-shaped element.

[0006] The object of the present invention is also achieved with the initially mentioned heat treatment installation in which the heating device is designed according to the invention.

[0007] Advantageously, the plate-shaped elements can be used to form a heating unit that creates a relatively low flow resistance for the gas flowing through it. This allows the pressure loss caused by the heating unit to be kept low. This is particularly advantageous in heat treatment systems or furnaces that use a high proportion of convection for heat transfer, such as bell-type furnaces.

[0008] According to one embodiment of the present invention, provision can be made for one, several, or all of the plate-shaped elements to have a meandering profile. This makes it possible to provide a high heating power while still achieving a relatively compact design. Furthermore, this allows the heating device to be easily adapted to the installation space in existing heat treatment systems.

[0009] To further improve these effects, according to an embodiment of the invention, it can be provided that the serpentine course has a plurality of bends, and that the sections of the plate-shaped elements between the bends optionally have parallel courses relative to one another. In particular, the latter embodiment allows for improved space utilization.

[0010] To better integrate the heating device or the plate-shaped element into the heat treatment system, one embodiment of the invention can provide for receiving elements for the fixing elements to be provided in several or all of the bends. This allows for a compact design of the heating device without the risk of accidental contact between sections of the plate-shaped element or the plate-shaped element. This also allows for higher flow rates in the heat treatment system.

[0011] According to an embodiment variant of the invention, it can be provided that the meandering course is designed as a double meander, thereby enabling simpler contacting of the plate-shaped elements in a single region of the heating unit and also increasing the heating power per plate-shaped element.

[0012] According to another embodiment variant of the invention, it can be provided that the plate-shaped element is bent in a scoop-shaped manner, whereby the plate-shaped element can also assume a flow-guiding function in addition to the “heating” function.

[0013] According to another embodiment of the present invention, grooves may be provided in the plate-like element at least in sections, thereby imparting improved stability to the plate-like element even at a relatively low thickness. This prevents or reduces "vibration" of the plate-like element during flow. Furthermore, the grooves contribute to improved heat transfer between the flowing medium and the plate-like element.

[0014] According to an embodiment variant of the present invention, it can be provided that the plate-shaped element has a plate thickness between 0.5 mm and 5 mm, whereby the above-described low pressure loss effect can be further improved.

[0015] In addition to the aforementioned double meander configuration for extending the length of the heating conductor, according to another embodiment variant of the invention, provision can also be made for a plurality or all of the plate-shaped elements to be electrically connected in series in order to form a heating assembly.

[0016] According to an embodiment of the present invention, it can be provided that the plate-like elements connected in series are stacked one above the other, with electrical insulation elements being arranged between the plate-like elements. Stacking can also achieve a compact structure.

[0017] According to an embodiment variant of the present invention, it can also be provided that the three heating assemblies are electrically connected to one another in a star connection or a delta connection, whereby the total heating power of the heating unit can be increased.

[0018] According to an embodiment variant of the heat treatment device, for better transfer of heating energy, provision can be made for the heating device to be arranged in a flow channel for the gaseous medium, in particular a circulating air channel.

[0019] The flow channel can also be formed by a guide having guide fins, so that according to another embodiment of the heat treatment system, the heat treatment system can also include a guide having guide fins, between which the heating device according to the invention is arranged. Advantageously, the plate-shaped elements of the heating device are curved in a scoop shape, so that they act in the manner of other guide fins.

[0020] According to another embodiment variant of the heat treatment plant, it can be provided that the plant also has a gas-operated heating device. By combining an "electric heating device" with a "gas-operated heating device", a reduction in the nitrogen oxide (NOx) content in the exhaust gas can be achieved during non-optimal phases (such as, for example, during a maintenance phase with reduced burner power). With the hybrid design of the heat treatment plant, it is possible to operate these phases of reduced burner power with the help of the heating device according to the invention and not operate the gas burner during these phases. It is therefore also possible to reduce the total heating power of the gas burner and to provide the missing heating power via the heating device. As a result, the gas burner is operated in the optimal range over a longer period, which in turn makes it possible to reduce the nitrogen oxide content in the exhaust gas.

[0021] According to another embodiment variant of the heat treatment installation, the heat treatment installation is designed as a pusher furnace, a bell furnace or a chamber furnace. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] For a better understanding of the present invention, the present invention will be explained in detail with reference to the following drawings.

[0023] In the simplified schematic diagram:

[0024] Figure 1 An oblique view showing an embodiment variant of the heating device;

[0025] Figure 2 An oblique view showing an embodiment variant of a plate-shaped element of a heating device;

[0026] Figure 3 Another embodiment variant of the plate-shaped element of the heating device is shown;

[0027] Figure 4 Another embodiment variant of the plate-shaped element of the heating device is shown;

[0028] Figure 5 A view showing the heating device along the flow direction of the gas to be heated;

[0029] Figure 6A detailed view showing the heating device;

[0030] Figure 7 Another detailed view showing the heating device;

[0031] Figure 8 A partial view showing an embodiment variant of a heat treatment device;

[0032] Figure 9 A longitudinal section showing an embodiment variant of a heat treatment apparatus;

[0033] Figure 10 A partial view showing another embodiment variant of the heat treatment device;

[0034] Figure 11 A detail of another embodiment variant of a heat treatment installation is shown. DETAILED DESCRIPTION

[0035] First, it should be noted that identical components are provided with identical reference numerals or component names in the various embodiments described, and that the disclosure contained throughout the entire description can be transferred to identical components having identical reference numerals or component names. Positional designations selected in the description, such as "upper," "lower," "lateral," etc., also refer to the directly described and illustrated figures, and these positional designations are transferred to the new position in the event of a change in position.

[0036] exist Figure 1 A heating device 1 is shown in FIG.

[0037] The heating device 1 can be used, in particular, in electrically heated convection furnaces or also for converting a furnace with a burner heating device into an at least partially electrically heated furnace. The heating device 1 can be used, for example, in a so-called vertical furnace or continuous furnace, i.e. in a so-called industrial furnace. An industrial furnace is defined as a space enclosed by walls in which heat is supplied to an object, in particular so that a process is carried out in or on the surface of the object. The object can be a product (such as, for example, a plate or slab, a block, etc.) or a raw material (such as, for example, a metal, etc.). The process can be, for example, the melting of the object or a certain reaction in or on or with the object (such as, for example, a phase change, hardening of a metallic object, tempering of an object, etc.). These enumerations are merely exemplary and should not be understood in a restrictive manner. In general, the heating device 1 can be used in a heat treatment device 2 in order to thus perform heat treatment on an object, i.e., to process it at a high temperature, in batches or continuously. A partial view of an example of a heat treatment device 2 is shown in Figures 8 to 11 Depicted in.

[0038] Industrial furnaces within the meaning of the present invention are, in particular, furnaces used in metallurgy or for processing inorganic objects or objects consisting exclusively of inorganic raw materials.

[0039] It is also to be noted, purely by way of example, that the heating device 1 can be used for objects consisting of aluminum or an aluminum alloy or generally non-ferrous metals or of steel.

[0040] Heating device 1 includes at least one heating unit 3. Heating unit 3 includes or is composed of a plurality of resistance heating elements. When current flows through them, heat is generated due to the resistance. Since this principle is well known, reference will be made to the relevant prior art to avoid repetition.

[0041] The resistance heating element is constructed as a plate element 4 or a plate element. Figure 2 Shown in.

[0042] A sheet metal within the meaning of the present invention is a metal product whose width and length are significantly greater than its thickness. Accordingly, the plate-shaped element 4 is understood to be a flat metal material piece of uniform thickness at all points, except for tolerances, and delimited on two opposite sides by a plane extending relative to the thickness.

[0043] It should be noted that all or several resistance heating elements of a heating device 1 can be constructed identically. Although this is a preferred embodiment of the heating device 1, it is also possible within the scope of the present invention to install different plate-shaped elements 4 in the heating device 1. These plate-shaped elements can be arranged within the same heating device 1 or, if multiple heating devices 1 are present in the heat treatment system 2, in different heating devices 1. The differences can lie in the plate thickness 5, the length through which the current flows, the number of bends, the material, etc., or in a combination thereof.

[0044] Only one plate-shaped element 4 is described in detail below. However, the embodiments described here can be transferred to the other or all plate-shaped elements 4 of the heating device 1 .

[0045] The plate element 4 Figure 2 The embodiment shown in FIG is a preferred embodiment. However, the plate-shaped element 4 can also have a completely different appearance. For example, in its simplest form, the plate-shaped element 4 can be a straight, flat rod. However, in a preferred embodiment, the plate-shaped element 4 has a meandering course with bends 6 (also called apex regions) and sections 7 between the bends 6. Figure 2 The number of bends 6 specifically shown and the corresponding number of segments 7 should not be interpreted as limiting. The specific number may also depend on the desired total heating power of the heating device 1 and / or the installation situation. For example, a plate-shaped element 4 can have between two and 50 such bends 6, in particular between 6 and 45, for example between 10 and 40.

[0046] Thus, the segments 7 can extend at an angle relative to one another, so that the distance 8 between the segments 7 increases starting from the respective bend 6. However, in a preferred embodiment variant, it can be provided that, as in Figure 2 As shown in FIG, the sections 7 of the plate-shaped element 4 between the bends 6 have a parallel course relative to one another.

[0047] The distance 8 between the segments 7 may be between 1 mm and 50 mm.

[0048] The width 9 of the section 7 can be between 2 mm and 100 mm, in particular between 10 mm and 60 mm.

[0049] The plate thickness 5 can be between 0.5 mm and 5 mm, in particular between 1 mm and 2 mm. Therefore, the plate-shaped element 4 is relatively thin, so that it has a low flow resistance. For this purpose, reference can be made to Figure 5 ,Should Figure 5 The heating device 1 is shown in the flow direction (perpendicular to the paper plane).

[0050] The total length of the plate-shaped element 4 along the current flow direction may be between 100 mm and 3 m.

[0051] The plate-shaped element 4 can be produced by correspondingly shaping a straight blank. There is also the possibility of casting the plate-shaped element 4 into the desired shape. However, the plate-shaped element 4 is preferably cut out of the sheet material by means of a separating method (for example using a laser or a water jet).

[0052] The plate-shaped element 4 comprises at least one metal material or is made of it. alloy, alloy or Alloy composition.

[0053] like Figure 3 and Figure 4 As explained by way of example, the meandering course of the plate-shaped element 4 can also be configured differently. Instead of the circular bend 6, for example, right-angled transitions 10 can be provided between the sections 7, as in Figure 3 In addition, it can be provided that the serpentine direction is constructed as a double serpentine portion ( Figure 4 ), so that, for example, two electrical connection areas of the plate-shaped element 4 are arranged side by side.

[0054] To construct the heating unit 3, the plate-shaped element 4 can be arranged in a receiving element, such as, for example, a frame element 11, as is the case in Figure 1 、 Figure 5 and Figure 6. In principle, the plate-shaped element 4 can be connected to the receiving element or arranged therein or on it in various ways and methods. For example, the receiving element can be provided with groove-shaped recesses into which the plate-shaped element 4 can be inserted. These recesses can optionally be designed with undercuts.

[0055] However, in the embodiment variant shown, the plate-shaped elements 4 are arranged one above the other or suspended in a side-by-side arrangement in the frame element 11, depending on the installation position. For this purpose, according to one embodiment variant, the plate-shaped elements 4 can be provided with a receiving element 12 for a fixing element 13 (also referred to as a retaining element) of the frame element 11. The receiving element 12 can be designed as a receiving lug, which is provided, for example, in the vertex region of the bend 6, as in the embodiment variant. Figure 2 Here, preferably, each bend 6 is provided with such a receiving element 12, so that the plate-shaped element 4 can be connected to the frame element 11 at each bend 6. For connection or joining, the frame element 11 can have rod-shaped fixing elements 13, which extend through the penetration of the receiving element 12 of the plate-shaped element 4. In other words, the plate-shaped element 4 can be strung onto the frame element 11, as can be done, for example, from Figure 5 or Figure 6 The rod-shaped or bar-shaped fixing element 13 can be held by the end plate 14 of the frame element 11 .

[0056] The receiving element 12 of the plate-shaped element 4 can also be designed differently, as can be done, for example, from Figure 11 See.

[0057] The receiving element 12 is preferably formed integrally with the rest of the plate-shaped element 4 .

[0058] To facilitate the stacking of the plate-like elements 4, insulating elements 15 are provided between them. The insulating elements 15 can extend through the receiving element 12, for which purpose the openings in the receiving element 12 can be designed to be correspondingly large. In a preferred embodiment, the insulating element 15 is sleeve-shaped, allowing the fastening element 13 to extend through it. Thus, the insulating element 13 not only provides electrical insulation between adjacent plate-like elements, but also provides electrical insulation from the frame element 11 (or, in general, from the receiving element for the plate-like elements 4).

[0059] The insulating element 15 can consist of materials known for electrical insulating elements 15, but these materials must also withstand the temperatures in the heat treatment device 2. For this reason, the insulating element 15 is preferably designed as a ceramic element.

[0060] If you can Figure 5 and Figure 6As can be seen, two sleeve-shaped insulating elements 15 of different structures can be used, and the insulating materials can be plugged into each other. This simplifies the assembly of the heating device 1 and the centering of the plate-shaped element 4.

[0061] In order to preferably assemble the heating device 1, in a first step a frame element 11 can be provided, which, however, does not yet have an end plate 14 on at least one side. A first insulating element 15 is then placed on each of the fixing elements 13. These first insulating elements 15 are supported on one of the end plates 14 and establish electrical insulation from this / these end plates 14. The first plate-shaped element 4 is then pushed so that the fixing element 13 protrudes through the receiving element 12. The centering of this plate-shaped element 4 is carried out using a second insulating element 15, which has a cylindrical projection that can be accommodated by the first insulating element 15, as can be seen from the diagram. Figure 6 The further construction of the heating unit 3 is carried out by repeating these steps.

[0062] In principle, the electrical connection of the plate-shaped element 4 can be made on two opposite sides of the heating device 1. However, in a preferred embodiment variant, these connections are provided on the same side of the heating device 1. For this purpose, so-called connecting lugs 16, 17 can be provided or arranged and connected to the plate-shaped element 4. For electrical connection only on one side, for example, a plate-shaped element 4 designed as a double meander can be used.

[0063] According to another embodiment variant, it can also be provided that a plurality of or all plate-shaped elements 4 of the heating device 1 are electrically connected in series in order to form a heating assembly 18. Figure 1 In the embodiment variant shown, the heating device has three such heating elements 18. The heating elements 18 can also be arranged on the same frame element 11, for example separated by intermediate plates 19 (see FIG. Figure 5 ).

[0064] To establish a series connection of the plate-like elements 4, metallic current connection elements 19 are provided alternately (at the beginning and end of the plate-like elements 4) in the end regions of the plate-like elements 4. These current connection elements conduct the current from one plate-like element 4 in a first plane to one plate-like element 4 in the next plane. The current thus flows through the heating assembly 18 in a zigzag manner.

[0065] Likewise, the current connection element 19 is preferably designed in the form of a sleeve. It can have cylindrical projections on one or both sides, which can be accommodated by the adjacent insulating element 15. Likewise, the current connection element 19 can have a centering function for centering the plate-shaped element 4.

[0066] If you can Figure 2 As can be seen in FIG. 4 with reference to a section 7, according to one embodiment variant of the heating device 1, provision can be made for grooves 20 to be provided or formed in the plate-shaped element 4 at least in individual sections 7, in particular in all sections 7. The grooves 20 can be produced by shaping the sections 7. The grooves 20 can have a depth of between 0.5 mm and 3 mm.

[0067] All plate-shaped elements 4 of the heating device 1 can be connected in series. However, in order to increase the total heating power, according to an embodiment variant, it can be provided that the heating device 1 has three heating components 18, as in Figure 1 Here, the three heating components 18 can be electrically connected to each other in a star connection or a delta connection. Figure 7 ,Should Figure 7 The star connection of the three heating elements 18 is shown. The electrical connections 21 to 23 for the three phases P1, P2 and P3 as well as the star point connection 24 can be seen. Subsequently, the connection to the power supply unit 25 (see FIG. 24) is carried out via these electrical connections 21 to 23. Figure 1 ) is connected, and the heating unit 3 can be powered by the power supply unit.

[0068] Depending on the required heating power, the heat treatment apparatus 2 may include one heating device 1 or multiple heating devices 1. For example, one heat treatment apparatus 2 may include 1 to 20 heating devices 1.

[0069] As already explained above, the heating device 1 is used in the heat treatment installation 2 to warm or heat a gaseous medium, such as circulating air, through which energy is then supplied to the object to be heat treated.

[0070] exist Figure 8 A first embodiment variant of a heat treatment system 2 is partially shown in FIG. This heat treatment system comprises a treatment chamber 26 for accommodating at least one object to be treated. Furthermore, the heat treatment system 2 comprises at least one heating device 1 according to the present invention (preferably multiple heating devices 1). The heating devices 1 can be arranged within and / or outside the treatment chamber 13 and at least partially surround the treatment chamber. The at least one heating device 1 can be arranged in a flow channel 27 that is at least partially, preferably completely, within a housing 28 of the heat treatment system 2. In the embodiment variant shown, the heat treatment system 2 is a so-called pusher furnace.

[0071] The flow channel 27 can be completely separated from the process chamber 26 by passing through a gas guide plate 29 .

[0072] The heat treatment device 2 may also have other components corresponding to the prior art, but these components are not mentioned in this specification. Those skilled in the art will arrange these components in the heat treatment device 2 accordingly when necessary.

[0073] The gaseous medium to be heated can be selected or composed according to the thermal process in the heat treatment device 2. This is also known to those skilled in the art, so that no further discussion is required.

[0074] It is generally preferred to have a W / cm 2 , especially 0.5W / cm 2 Up to 25W / cm 2 The heating device 1 is used in a heat treatment device 2 with an energy density between 100 and 1000 Å. The energy density is dependent on the flow medium (particularly the type of medium, the velocity of the medium and the temperature of the flow medium).

[0075] exist Figure 9 , a detail of another embodiment of a heat treatment system 2 is shown. This heat treatment system is designed as a bell-type furnace. As in pusher-type furnaces or heat treatment systems 2 in general, a fan 30 or a turbine can be provided to circulate the gaseous medium in the treatment chamber 26. The heating device 1 can be arranged in a flow channel 27 arranged centrally above the fan 30.

[0076] The heating device 1 or one or more additional heating devices 1 can also be arranged in a differently designed flow channel 27. For this purpose, for example Figure 10 1 shows a guide for the medium to be circulated. The guide has guide plates 31, between which the flow channels 27 are formed. The guide plates 31 are designed to be curved accordingly in order to achieve a corresponding flow path.

[0077] Now, the plate-shaped elements 4 of the heating device 1 are arranged between the guide plates 31 or at least between some of the guide plates 31. Figure 10 As can be seen, the plate-shaped element 4 is curved in a scoop-shaped manner and in particular at least approximately follows the curvature of the guide blades 31 , whereby the plate-shaped element 4 also contributes to the flow guidance and not only to the heating of the gaseous medium.

[0078] In accordance with Figure 10 In the embodiment variant of the heat treatment device 2, the plate-shaped element 4 is arranged upright between the guide plates 31, so that the meandering direction extends in the vertical direction. Figure 11 It is shown in FIG: the plate-shaped element 4 can also be arranged lying down. Figure 11 It is also shown that, as already explained above, the plate-shaped element 4 can also have the same Figure 2Here, a plurality of plate-shaped elements 4 can also be stacked in a vertical direction and electrically insulated from each other by insulating elements 15. The stack can again be held together by fixing elements 13, as has been explained above.

[0079] This embodiment variant also allows the variability and adaptability of the heating device 1 to different situations in an existing heat treatment system 2 to be demonstrated.

[0080] The heating device 1 can be provided or operated for heating a gaseous fluid individually, in an assembly of a plurality of heating devices 1 and / or in a combined application with at least one gas burner.

[0081] Besides the shown examples of a pusher furnace and a bell furnace, the heat treatment installation 2 can also be a chamber furnace or generally preferably a furnace installation with convection heating, such as a convection furnace or a roller hearth furnace for continuously running strips.

[0082] The exemplary embodiments show possible embodiment variants of the heating device 1 or the heat treatment installation 2 , it being noted that combinations of the individual embodiment variants with one another are also possible.

[0083] Finally, it should be pointed out that, for a better understanding of the design of the heating device 1 or the heat treatment installation 2 , it is not necessarily shown to scale.

[0084] Reference Signs List

[0085] 1 Heating device

[0086] 2Heat treatment equipment

[0087] 3 heating units

[0088] 4 plate components

[0089] 5 board thickness

[0090] 6 bending part

[0091] 7 sections

[0092] 8Distance

[0093] 9 width

[0094] 10 Transition

[0095] 11 frame elements

[0096] 12 accommodating components

[0097] 13Fixing elements

[0098] 14 end plate

[0099] 15 Insulation elements

[0100] 16 connecting lugs

[0101] 17 connecting lugs

[0102] 18 heating components

[0103] 19 Current connection element

[0104] 20 grooves

[0105] 21 connectors

[0106] 22 connectors

[0107] 23 connectors

[0108] 24 star contact connection

[0109] 25 power supply units

[0110] 26 processing rooms

[0111] 27 flow channels

[0112] 28 shell

[0113] 29 air guide plate

[0114] 30 fans

[0115] 31 guide piece

Claims

1. A heating device (1), comprising at least one heating unit (3), the heating unit having a plurality of resistance heating elements, characterized in that: The resistance heating element is configured as a plate-shaped element (4).

2. The heating device (1) according to claim 1, characterized in that One, a plurality of or all of the plate-shaped elements (4) have a serpentine course.

3. The heating device (1) according to claim 2, characterized in that The meandering course has a plurality of bends (6).

4. The heating device (1) according to claim 3, characterized in that The sections (7) of the plate-shaped element (4) between the bends (6) have a parallel course relative to one another.

5. The heating device (1) according to claim 3 or 4, characterized in that Receiving elements (12) for fixing elements (13) are provided in a plurality or in all of the bends (6).

6. The heating device (1) according to any one of claims 2 to 5, characterized in that The meandering course is configured as a double meander.

7. The heating device (1) according to any one of claims 1 to 6, characterized in that The plate-shaped element (4) is bent in a spade-shaped manner.

8. The heating device (1) according to any one of claims 1 to 7, characterized in that A groove (20) is provided in the plate-shaped element (4) at least on the section (7).

9. The heating device (1) according to any one of claims 1 to 8, characterized in that The plate-shaped element (4) has a plate thickness (5) between 0.5 mm and 5 mm.

10. The heating device (1) according to any one of claims 1 to 9, characterized in that A plurality of or all of the plate-like elements (4) are electrically connected in series to construct a heating assembly (18).

11. The heating device (1) according to any one of claims 1 to 10, characterized in that The plate-shaped elements (4) connected in series are stacked one above the other, and electrical insulating elements (15) are arranged between the plate-shaped elements (4).

12. The heating device (1) according to any one of claims 1 to 11, characterized in that The three heating assemblies (18) are electrically connected to each other in a star connection or a delta connection.

13. A heat treatment apparatus (2) comprising a treatment chamber (26) for an object to be treated and having a heating device (1) at least partially arranged in the heat treatment apparatus (2), characterized in that The heating device (1) is constructed according to any one of claims 1 to 12.

14. The heat treatment device (2) according to claim 13, characterized in that The heating device (1) is arranged in a flow channel (27) for a gaseous medium, in particular a circulating air channel.

15. The heat treatment device (2) according to claim 13 or 14, characterized in that The heat treatment apparatus further comprises a guide having guide fins (31), and a heating device (1) according to any one of claims 1 to 12 is arranged between the guide fins (31).

16. The heat treatment device (2) according to any one of claims 13 to 15, characterized in that The heat treatment system also has a gas-operated heater.

17. The heat treatment device (2) according to any one of claims 13 to 16, characterized in that The heat treatment equipment is configured as a pusher furnace, a bell furnace or a chamber furnace.

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