DE202021106375U1 - Heating device for a bar-like workpiece - Google Patents

Abstract

Heating device (1), in particular in-line furnace, for heating rod-like, electrically conductive workpieces (13), in particular metal rods and/or non-ferrous metal rods, which can be conveyed through the heating device (1) along a conveying direction (R), having, with respect to the conveying direction ( R) first heating module (2) with a first input area (4) and a first output area (5) and with respect to the conveying direction (R) second heating module (3) with a second input area (6) and a second output area (7) ,wherein the second heating module (3) is designed as an induction module (8), characterized in that the first heating module (2) is designed as a convection module (9) with heating means (10), the convection module (9) being designed and is set up that for heating the workpiece (13) a working gas between the heating means (10) and the workpiece to be heated (13) can be circulated, such that the working gas first through the Heizmi ttel (10) can be heated and the workpiece (13) can then be flown through by the heated working gas and that the first outlet area (5) is structurally arranged directly on the second inlet area (6).

Description

The present invention relates to a heating device for heating rod-like, electrically conductive workpieces, such as metal rods and/or non-ferrous metal rods, in the preferred embodiment aluminum rods.

Heating devices for rod-like, electrically conductive workpieces are generally known from the prior art. For example, describes the EP 2 337 871 B1 a generic heating device known as an inline oven for rod-like, electrically conductive workpieces that run through the heating device along a conveying direction and first pass through a first heating module for preheating and then a second heating module for final heating with higher heat output.

The preheating realized in the first heating module takes place by means of a conventional gas furnace, in which the flames produced during the combustion of the gas are used directly to heat the workpiece. For the realization of the second heating module, the generic heating device comprises an induction module, which comprises power coils for generating eddy currents in the workpiece to be heated, which extend along the conveying direction of the workpiece. Although the gas furnace and the induction module form a continuous heating chamber for the workpiece, they must have a thermal decoupling section to avoid flashover between the gas furnace and the induction module in order to prevent damage to the induction module from flashover flames. This is disadvantageous, since the decoupling section leads to an increase in the longitudinal extension of the heating device and thus increases the structural complexity for the manufacture of the heating device. In addition, the rod-like workpieces lose heat that has already been introduced when passing through the decoupling section, despite complex thermal insulation that causes additional costs, which is why the overall efficiency of the heating device is also reduced by the heat loss occurring in the decoupling section.

The present invention is therefore based on the object of specifying a heating device which overcomes the disadvantages known from the prior art. In particular, the object of the present invention is to specify a heating device that is compact in terms of its longitudinal extent and structurally simple to implement for efficient heating of the rod-like, electrically conductive workpieces before an immediately subsequent mechanical treatment by means of a pressing process.

This object is achieved by a heating device having the features of claim 1.

Advantageous developments of the invention are specified in the dependent claims. All combinations of at least two features disclosed in the description, the claims and/or the figures fall within the scope of the invention.

In the context of the present invention, a heating device is provided for heating rod-like, electrically conductive workpieces, in particular metal rods and/or non-ferrous metal rods such as aluminum rods, which can be conveyed through the heating device along a conveying direction, with a first heating module in relation to the conveying direction, which has a first Includes an input area and a first output area and with a second heating module with respect to the conveying direction, which has a second input area and a second output area, wherein the second heating module is designed as an induction module for inductive heating of the electrically conductive workpiece.

Furthermore, the invention provides that the first heating module is designed as a convection module with heating means, which is designed and set up in such a way that a working gas can circulate between the heating means and the workpiece to be heated, in order to first heat the working gas with the heating means and then the Flow towards the workpiece with the working gas to introduce heat output. In addition, it is provided according to the invention that the first exit area is structurally arranged directly on the second entry area, which results in an advantageous minimization of the longitudinal extension of the heating device in accordance with the invention in order to form an energetically efficient and structurally compact heating device. Furthermore, the outlay on components can thus be reduced since a decoupling section that is customary in the prior art can be completely dispensed with.

In other words, the longitudinal extension of the heating device according to the invention can be shortened by the structurally direct arrangement of the first output area on the second input area. This is advantageously made possible according to the invention, since no decoupling section is required in the present inventive heating device, since the temperature control by means of the working gas does not lead to the formation of flames. In addition to shortening the longitudinal extent, this also leads to an improved Overall efficiency of the heating device, since there is no temperature loss in the workpiece when passing through the decoupling section. Furthermore, the structural complexity can be reduced by eliminating the decoupling section.

Due to the inventive implementation of the first heating module as an inventive convection module with the heating means, the workpiece is heated only by means of the working gas heated by the heating means, which circulates between the workpiece to be heated and the heating means. Flame formation in the first heating module can thus advantageously be completely avoided, which is why the second heating module can be structurally arranged directly next to the first heating module. The decoupling section is thus completely eliminated. Furthermore, the temperature of the working gas in the convection module according to the invention can be precisely controlled and regulated via the heating means, which is why the heat output that can be introduced into the workpiece can be precisely regulated in the first heating module.

According to a development of the present invention, the heating means are designed as a gas burner, preferably a recuperation burner, and as an electrical resistance heating element, preferably a resistance-heated heating register. This is advantageously realized by a hybrid convection module in order to heat the circulating working gas either in the conventional way with a fuel, in particular a fossil fuel, ie gas in the present case, or by means of electrical energy. This advantageously leads to a wide range of uses for the heating device, in order to also enable operation independently of a fossil fuel, in particular gas.

In addition, a development of the heating device according to the invention provides that the convection module for conducting the working gas includes ventilation ducts, the ventilation ducts being designed in such a way that the air heated in the heating means can be guided to the workpiece as evenly as possible and without major temperature loss, in order to cover the workpiece over as large an area as possible flow with the heated working gas and thus realize a high heat input into the workpiece. In addition, the ventilation ducts enable a structural separation between the supply air and exhaust air of the working gas acting on the workpiece in order to avoid contact of the heated working gas before the workpiece flows with already cooled working gas after the flow.

Furthermore, the configuration of the ventilation ducts enables the formation of a circuit for the working gas in order to enable the efficient heating of the workpiece by means of the working gas, which has been repeatedly heated by the circulation with the heating means and is therefore already pre-tempered.

In a further development, it is provided that the convection module includes gas conveying means, in particular a ventilator or fan, for controlling and/or influencing an average flow rate of the working gas, in particular when it flows through the ventilation ducts.

Advantageously, the gas conveying means allow additional control and influencing of the heating process of the workpieces, since the flow rate of the working gas when it flows against the workpiece can be influenced and thus also increased in order to achieve the highest possible heat input into the workpiece.

Furthermore, the working gas is preferably at least partially sucked in by the gas conveying means after it has flowed against and around the workpiece, in order to be heated again by the heating means to a flow temperature of between 730° C. and 750° C. and thus to achieve a high system efficiency. The gas conveying means preferably also enable the average flow rate of the working gas to be adapted specifically to the temperature difference between the heating means and the workpiece in order to implement individual temperature profiles depending on the different material properties of the workpiece, such as the thermal diffusivity, or different diameters of the rod-like workpiece.

In a further development, it is also provided within the scope of the present invention that the convection module comprises a control unit for controlling an operating mode of the gas burner and the electrical resistance heating element, the control unit being designed such that, depending on user-generated and/or parameter-generated input signals, in a first operating mode only the gas burner, in a second operating mode only the electrical resistance heating element and in a third operating mode simultaneously the gas burner and the electrical resistance heating element can be activated for heating the working gas.

In the context of the present invention, the user-generated input signals are understood to mean the selection of the operating modes of the heating means by an operator. So it is provided, for example, in this context that the operator for the complete heating process of the workpiece with the heating device according to the invention only the gas burner than Heating means is selected, wherein when passing through the first heating module, the workpiece is thus flown only by the working gas designed as hot exhaust air, which was previously heated by the gas burner. This advantageously leads to a reduction in the required electrical energy of the heating device, which is required for heating the workpiece, since the operation of the first heating module is also possible using gas as the energy source.

Alternatively, the selection of the operating modes can also be parameter-generated, in which case there is a communication connection between the control unit and a communication partner in order to use data such as the share of renewable energies in the current electricity generation of an energy system or current energy costs, such as a current electricity price (Instantaneous value) in relation to costs for a fossil fuel to enable automated activation of the operating modes. In the event of a surplus of renewable energies, for example, a large proportion of the thermal energy can be generated based on resistance, i.e. purely conductively, in order to benefit from low electricity prices. Advantageously, the present development also enables optimized operation in order to technically implement a reduction in CO2 and impending fines in addition to the operating costs. The preferred design of the heating means as a gas burner also makes it particularly advantageous to operate with hydrogen produced from renewable energies, in order to also enable CO2-free operation of the heating device when using the gas burner.

In a further development, it is provided that the convection module includes nozzle means for influencing the average flow rate of the working gas when it hits the rod-like workpiece.

Advantageously, the nozzle means enable the heat input into the workpiece to be maximized, since the flow rate of the working gas can be specifically influenced and thus optimized immediately before the workpiece flows. This preferred configuration also leads synergistically to a reduced overall length of the heating device according to the invention, since the heat input into the workpiece can be maximized at a constant conveying speed of the workpiece.

Particularly preferred in this context is the configuration of the nozzle means as a large number of slotted nozzles which are arranged adjacent to one another in the conveying direction of the workpiece and in particular extend in sections on the jacket side of the conveyable rod-like workpiece. Due to the large number of slot nozzles, the heated working gas is guided radially to the rod-like workpiece on the outer surface of the workpiece in order to achieve a large-area and therefore optimal inflow in relation to the heat input. The fan-like slit nozzles are formed by V-shaped wall sections in order to achieve an average flow rate of the working gas of up to 50m/s. The overall length of the heating device can also be reduced by the preferred configuration of the nozzle means by the plurality of slotted nozzles in order to achieve the compact longitudinal extent of the heating device according to the invention.

Furthermore, it is provided that the first heating module comprises at least two heating zones with a first convection module and at least one second convection module. Advantageously, this enables independent regulation of the temperature along the longitudinal extent of the heating device in the conveying direction, in order to heat the temperature of the working gas in particular to a value in the range from 730°C to 750°C and thus the workpiece to a temperature in the range of 380°C to be tempered up to 450°C. A high temperature gradient between the heated working gas and the (still untempered) workpiece is preferably used in the first heating zone in order to realize a large temperature gradient and thus maximize the heat input into the workpiece. This advantageously contributes to the fact that the longitudinal extent of the heating device can be minimized. Alternatively, it is also preferred to regulate the temperature in the different heating zones individually, for example in order to realize an axial temperature profile, in particular a gradual temperature increase.

In this context, it is also provided in a further development that the induction module also has at least two independently controllable heating zones with a first induction module and at least one second induction module. This also enables the rod-like workpiece to be subjected to an axial temperature profile in order to implement an individual heating characteristic depending on the geometry of the rod-like workpiece and/or the material composition of the workpiece.

In a further development, it is also provided that the first heating module and the second heating module are designed in such a way that the conveying direction in the first heating module and the conveying direction in the second heating module extend along a common longitudinal axis, i.e. the heating device extends along a straight line, to put it another way. Advantageous this leads to a simplified structural realization of the heating device, since the workpieces only have to be moved transversely when passing through the heating device, ie they have to be conveyed along a common axis of extension.

Finally, a development of the heating device is particularly preferred in which the first heating module has a longitudinal extension in the conveying direction of between 6m and 15m, preferably 6m to 12m, particularly preferably 6m to 10m and in which the second heating module has a longitudinal extent in the conveying direction of between 0.5m and 4m , preferably 0.8m to 2m, particularly preferably 0.8m to 1.6m.

The details of the heating device illustrate the compact extension dimensions of the heating device according to the invention, which enables efficient hybrid heating of the workpiece and is characterized by a compact longitudinal extension.

Further advantages and details of the invention result from the following description of preferred embodiments of the invention as well as from purely schematic drawings.

• 1: eine erfindungsgemäße Heizvorrichtung gemäß einer ersten Ausführungsform, in
• 2: eine erfindungsgemäße Heizvorrichtung gemäß einer zweiten Ausführungsform, in
• 3: eine Schnittansicht der aus der 1 bekannten Heizvorrichtung gemäß der ersten Ausführungsform, in
• 4: eine perspektivische Darstellung der erfindungsgemäßen Heizvorrichtung gemäß der ersten Ausführungsform und in
• 5: eine perspektivische Darstellung der erfindungsgemäßen Heizvorrichtung gemäß der zweiten Ausführungsform.

Show it:

• 1 : a heating device according to the invention according to a first embodiment, in
• 2 : a heating device according to the invention according to a second embodiment, in
• 3 : a sectional view of the from the 1 known heating device according to the first embodiment, in
• 4 : a perspective view of the heating device according to the invention according to the first embodiment and in FIG
• 5 1: a perspective representation of the heating device according to the invention according to the second embodiment.

Identical elements or elements with the same function are provided with the same reference numbers in the figures.

In the 1 a side perspective view of a first preferred embodiment 1A of a heating device 1 according to the invention for heating rod-like, electrically conductive workpieces 13 is shown, which can be conveyed along a conveying direction R through the heating device 1 according to the invention to carry out the heating.

The heating device 1 according to the invention comprises a first heating module 2 and a second heating module 3. The first heating module 2 has a first inlet area 4 and a first outlet area 5, and the second heating module 3 comprises a second inlet area 6 and a second outlet area 7.

The second heating module 3 is designed as an induction module 8 in order to heat the electrically conductive workpiece 13 by eddy currents, which can be generated by means of power coils that can be energized as a result of generated magnetic fields. The power coils enclose the workpiece 13 to be heated (material to be heated) concentrically, with a time-varying magnetic field being able to be generated by the power coils in order to generate the eddy currents required for heating in the metallic workpiece 13

The power coils are designed either as induction coils that can be charged with an alternating current or preferably as rotating permanent magnets. The permanent magnets, which are arranged around the workpiece 13 to be heated, can be set in rotary motion either directly as a rotor or indirectly via a belt drive, in order to thus generate the time-varying magnetic field.

The first heating module 2 is designed as a convection module 9 with heating means 10 (not shown in detail in the figure), the convection module 9 being designed such that a working gas can circulate between the heating means 10 and the workpiece 13 that can be picked up and is to be heated, the working gas flowing through of the heating means 10 is first heated and then heat is introduced into the workpiece 13 by the flow against the workpiece 13 . The convection module 9 of the first embodiment has a modular structure and includes two heating zones, each of which includes heating means 10 and can be operated independently of one another.

In the illustrated embodiment, the heating means 10 comprise both a gas burner 11, in order to enable the working gas to be heated by the combustion of a gaseous fuel, and an electrical resistance heating element 12, which is not shown in detail in the figures, which in the present case is formed by a resistance-heated resistance register 23 and the heating of the working gas by converting electrical energy into thermal energy.

The graphic representation also shows that the first output area 5 is structurally arranged directly on the second input area 6, which explains the compact design of the heating device 1 according to the invention with regard to the longitudinal extent in the conveying direction R. Beneficial comes namely, when the workpiece 13 is heated with the convection module 9, no flames form, which is why a decoupling section—as is known, for example, from the generic prior art—can be dispensed with.

During operation, the rod-like workpieces 13 to be heated are introduced into the heating device 1 through the first input area 4 and are transported by handling means in the form of rollers 20 along the conveying direction R through the first output area 5 into the second heating module 3 arranged directly behind it.

Advantageously, the heating device 1 according to the invention initially enables the workpieces 13 to be preheated by the convection module 8 to a temperature of between 380° C. and 450° C. by the circulating working gas, which is periodically heated by the heating means 10 to a temperature in the range of 730° C. to 750 °C is heated. The workpiece 13 is then further heated in the induction module 9 with high power in order to heat the workpiece to a final temperature of between 500° C. and 560° C. or preferably to a final temperature of up to 1000° C.

If the workpiece 13 comprises an aluminum alloy, it is preferred if the final temperature after passing through the induction module 9 is in the range from 500° C. to 560° C. Alternatively, the workpiece 13 can also comprise another non-ferrous metal, in particular copper or a copper alloy, in which case it is preferred if the preheating takes place to a temperature in the range from 580° C. to 600° C. and the final temperature after passing through the induction module 9 is between 700°C to 1000°C.

In the 2 a highly schematized side view of the heating device 1 according to the invention is shown according to a second preferred embodiment 1B. The illustration makes it clear that the heating device 1 is of modular design in relation to the conveying direction R. The first heating module 2 initially comprises two heating zones, the first heating zone being formed from a first convection module 81 and the second heating zone being formed from a second convection module 82, which are arranged directly adjacent to one another. The temperature in the first convection module 81 can advantageously be regulated independently of the temperature in the second convection module 82 .

Furthermore, the induction module 8 is also divided into individually controllable zones, which are formed by a first induction module 91 and a second induction module 92 . Advantageously, the subdivision of the heating device 1 into differently controllable zones enables the realization of axial temperature profiles in order to enable individual heating of the rod-like workpieces 13 .

the 3 shows a cross section of the heating device 1 according to the invention from FIG 1 known first embodiment 1A in the area of the first heating module 2. On the one hand, the illustration shows the rod-like workpiece 13 to be heated when passing through the heating device 1, which has a circular cross-section and is mounted on several rollers 20, which form the handling means, in order to move along the Conveying direction R to go through the heater 1 translative.

In relation to a vertical direction H of the heating device 1 above the workpiece 13 is a steel tube 21 with openings 24 on the shell side (not shown graphically) which is a component of the gas burner 11 designed here as a recuperative burner 22 in order to heat the working gas or at least partially heat it up to generate the combustion air.

In relation to the vertical direction H above the steel tube 21, the gas conveying means 17 are arranged, which in the present case are formed by a fan 18 and partly suck in the combustion air for forming the working gas from the steel tube 21 in the vertical direction H, and then the working gas via ventilation ducts provided laterally opposite 16, which are arranged mirror-symmetrically to the workpiece 13 on both sides.

The ventilation ducts 16 are arranged and designed in such a way that the working gas flows through the electrical resistance heating element 12 for alternative or additional heating of the working gas by means of electrical energy. In other words, the electrical resistance heating element 12, which is embodied here as a resistance-heatable heating register 23, is located between the gas conveying means 17 and the workpiece 13 to be flowed on or to be heated with respect to the flow path of the working gas.

Nozzle means 14 are formed at the end of the ventilation channels 16 in order to optimize the average flow rate of the working gas when it hits the workpiece 13 to be heated for a high heat input during active operation of the heating device 1 according to the invention.

During operation of the heating device 1 according to the invention, the combustion air in the area of the steel tube 21 reaches about 1000°C. The combustion air is sucked in by the gas conveying means 17 and guided along the ventilation ducts 16 via the electrical resistance heating element 12 onto the workpiece 13, with an average flow rate of up to 50 m/s being able to be achieved through the nozzle means 14. Thus, in an operating mode of the heating device 1 according to the invention, a first operating mode is implemented by a control unit 19 (not shown in detail), in which the working gas is generated and heated by the gas burner 11 .

In the 4 is a perspective sectional view of the from 1 known heater 1 shown according to the first embodiment 1A. The sectional view shows areas of the first heating module 2 of the heating device 1 according to the invention, which is formed by the convection module 9 with hybrid heating means 10 .

The illustration shows that the gas burner 11 designed as a recuperative burner 22 extends along the conveying direction R over the rod-like workpiece 13 that can be accommodated. Also visible are the openings 24 formed in the steel tube 21 on the shell side, from which the gases produced during the combustion process emerge as hot combustion air for forming the working gas, which is then sucked in in the vertical direction H by the gas conveying means 17 .

The working gas flows via the ventilation ducts 16 formed on the side via the resistance heating register 23 arranged on both sides onto the workpiece 13, it now being apparent that the nozzle means 14 formed at the end of the ventilation ducts 16 are configured as a large number of slotted nozzles 15, which are arranged on the peripheral side of the workpiece 13 that can be accommodated and lead to an increase in the mean flow rate of the working gas when the workpiece 13 flows, in order to optimize the heat input into the workpiece 13

In the 5 a further perspective view of the heating device 1 according to the invention is shown according to the second embodiment 1B.

In addition to the rod-shaped workpiece 13 to be heated, which is currently passing through the first heating module 2 and is thus flown by the working gas previously heated by the heating means 10 (not shown), the illustration also shows the large number of slotted nozzles 15, which ensure optimum heat input into the workpiece 13 realize.

The slotted nozzles 15 are arranged in some areas on the jacket side of the rod-like workpiece 13 in order to realize a substantially radial flow of the working gas onto the jacket surface of the workpiece 13 .

A slit nozzle 15 is formed by a pair of metal sheets arranged in a V-shape relative to one another, with an arcuate recess 26 being formed in the area tapering to a point for receiving the rod-shaped workpiece 13 .

Advantageously, the large number of slotted nozzles 15 synergistically enables the overall extension of the heating device 1 according to the invention to be shortened, since the heat input into the rod-shaped workpiece 13 can be improved.

It is also evident that the first heating module 2 shown comprises at least two heating zones with a first convection module 81 and at least one second convection module 82 which are separated from one another by a separating element 25 . This advantageously enables an axial temperature profile to be implemented in order to enable the heating process to be adapted for different material compositions of the rod-shaped workpiece 13 .

Reference List

1

heating device

1A

Heating device according to a first embodiment

1B

Heating device according to a second embodiment

2

first heating module

3

second heating module

4

first entrance area

5

first exit area

6

second entrance area

7

second exit area

8th

induction module

9

convection module

10

heating means

11

gas burner

12

electrical resistance heating element

13

workpieces

14

nozzle agent

15

slot nozzle

16

ventilation duct

17

gas conveyance

18

Fan

19

control unit

20

roll

21

steel pipe

22

recuperative burner

23

electrical resistance heating element

24

openings

25

separator

26

recess

81

first convection module

82

second convection module

91

first induction module

92

second induction module

R

conveying direction

L

longitudinal axis

H

vertical direction

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• EP 2337871 B1 [0002]

Claims (11)

Heating device (1), in particular in-line furnace, for heating rod-like, electrically conductive workpieces (13), in particular metal rods and/or non-ferrous metal rods, which can be conveyed through the heating device (1) along a conveying direction (R), having, with respect to the conveying direction ( R) first heating module (2) with a first input area (4) and a first output area (5) and with respect to the conveying direction (R) second heating module (3) with a second input area (6) and a second output area (7) , wherein the second heating module (3) is designed as an induction module (8), characterized in that the first heating module (2) is designed as a convection module (9) with heating means (10), the convection module (9) being designed and is set up that for heating the workpiece (13) a working gas between the heating means (10) and the workpiece to be heated (13) can be circulated in such a way that the working gas first through the He izmittel (10) can be heated and the workpiece (13) can then be flown by the heated working gas and that the first outlet area (5) is structurally arranged directly on the second inlet area (6). heating device after claim 1 , characterized in that the heating means (10) comprise a gas burner (11), in particular a recuperative burner (22), and an electrical resistance heating element (12), in particular a resistance-heated heating register. heating device after claim 1 or 2 , characterized in that the convection module (9) for guiding the working gas between the heating means (10) and the workpiece (13) to be heated comprises at least one ventilation duct (16). Heating device according to one of Claims 1 until 3 , characterized in that the convection module (9) comprises gas conveying means (17), in particular a ventilator or a fan (18), for controlling and/or influencing an average flow rate of the working gas, in particular in the at least one ventilation duct (16). Heating device according to one of Claims 1 until 4 , characterized in that the convection module (9) comprises a control unit (19) for controlling and/or activating an operating mode of the gas burner (11) and/or the electrical resistance heating element (12), the control unit (19) being designed and/or is set up that, depending on user-generated and/or parameter-generated input signals, in a first operating mode only the gas burner (11), in a second operating mode only the electrical resistance heating element (12) and in a third operating mode the gas burner (11) and the electrical resistance heating element ( 12) can be activated. Heating device according to one of Claims 1 until 5 , characterized in that the convection module (9) nozzle means (14) for influencing the flow rate of the working gas when it hits the rod-like workpiece (13). heating device after claim 6 , characterized in that the nozzle means (14) are designed as a plurality of slotted nozzles (15) which are arranged adjacent to one another in the conveying direction (R) and in particular partially extend on the shell side to the conveyable rod-like workpiece (13). Heating device according to one of Claims 1 until 7 , characterized in that the first heating module (2) comprises at least two heating zones with a first convection module (81) and at least one second convection module (82). Heating device according to one of Claims 1 until 8th , characterized in that the induction module (8) comprises at least two independently controllable heating zones with a first induction module (91) and at least one second induction module (92). Heating device according to one of Claims 1 until 9 , characterized in that the first heating module (2) and the second heating module (3) are designed such that the conveying direction (R) in the first heating module (2) and the conveying direction (R) in the second heating module (3) along a common Extend longitudinal axis (L). Heating device according to one of Claims 1 until 10 , characterized in that the first heating module (2) in the conveying direction (R) has a longitudinal extent of between 6m to 15m, preferably 6m to 12m, particularly preferably 6m to 10m and that the second heating module (3) in the conveying direction (R) has a longitudinal extent of between 0.5m to 4m, preferably between 0.8m to 2m, particularly preferably between 0.8m to 1.6m.

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