Heating apparatus for heating a metallic strip, system for managing an inner gas atmosphere, production line and method for heating a metallic strip

Abstract

The invention concerns to a heating apparatus for heating a metallic strip continuously conveyed on a conveyor line comprising a heating device, in particular wherein the heating device having a heating power density of greater than or equal to 60 kW / m2, a heating zone having an inner gas atmosphere, wherein the heating device is arranged, an inlet sealing device for transferring the metallic strip into the inner gas atmosphere, preferably an outlet sealing device for transferring the metallic strip out of the inner gas atmosphere, and an inner gas changing device having a charging device for charging inner gas, in particular fresh inner gas, into the heating zone and having a discharging device for discharging used inner gas out of the heating zone.

Description

[0001] Heating apparatus for heating a metallic strip, System for managing an inner gas atmosphere, Production line and Method for heating a metallic strip

[0002] The invention relates to a heating device for heating a metallic strip continuously conveyed on conveyor line in a conveying direction .

[0003] The invention relates to a system for managing an inner gas atmosphere on an electrical heating device for heating a metallic strip continuously conveyed on a conveyor line .

[0004] The invention relates to a production line for manufacturing and / or processing a metallic strip, in particular a semi-finished product and / or a preliminary product and / or an intermediate product and / or a product made of iron, steel and / or a nonferrous metal material, having a conveying line along which the metallic strip is continuously conveyed in a conveying direction, and having a heating section with a heating device for heating the metallic strip .

[0005] The invention also relates to a method for heating a metallic strip continuously conveyed on a conveyor line, wherein the metallic strip is continuously conveyed through a heating zone charged with an inner gas atmosphere .

[0006] It is known from the state of the art to heat a metallic strip once or several times, wherein the metallic strip is continuously conveyed along a conveyor line . For this, a heating device is provided on the conveyor line or several heating devices are provided on the conveyor line . Heating devices can have the same design, but they can also be different . The heating devices can also have different heating power or different heating power densities .

[0007] The obj ect of the invention is that of providing an improvement over or an alternative to the prior art .

[0008] According to a first aspect of the invention, the obj ect is achieved by a heating apparatus for heating a metallic strip continuously conveyed on a conveyor line comprising:

[0009] • a heating device, in particular wherein the heating device has a heating power density of greater than or equal to 60 kW / m2,

[0010] a heating zone having an inner gas atmosphere, wherein the heating device is arranged,

[0011] • an inlet sealing device for transferring the metallic strip into the inner gas atmosphere,

[0012] • preferably an outlet sealing device for transferring the metallic strip out of the inner gas atmosphere, and

[0013] • an inner gas changing device having a charging device for charging inner gas into the heating zone, preferably for charging fresh inner gas into the heating zone, and having a discharging device for discharging used inner gas out of the heating zone .

[0014] The heating device proposed here makes it possible to heat the metallic strip in a structurally compact and simple way, in particular with a structurally short heating section, to almost any desired temperature . Particularly if heating the metallic strip to a desired target temperature is aimed, in particular quickly, it is essential that the inner gas atmosphere in which the metallic strip is heated is of high quality in order to achieve a high strip quality. More precisely, it is essential that any metallic strip residues that may evaporate and / or pyrolyze on the metallic strip due to heating are removed by means of the inner gas atmosphere from the metallic strip . When strip residues vaporize and / or pyrolyze, the inner gas atmosphere becomes charged with these residues . As soon as this happens, we speak of used inner gas atmosphere .

[0015] Strip residues may contain vaporized and / or pyrolyzed organic compounds, in particular oil .

[0016] While the metallic strip is passing through the heating device, it is possible and / or intended that the metallic strip will exceed the vaporization temperature of the strip residues . If the used inner gas were now to flow within the heating apparatus in the opposite direction to the conveying direction of the metallic strip, it could enter an area in which the metallic strip has not yet exceeded the vaporization temperature of the strip residues . This could lead to strip residues, in particular aerosols, recondensing on the metallic strip and contaminating it .

[0017] Therefore, it is intended that used inner gas atmosphere is removed from the heating zone and inner gas atmosphere is supplied accordingly, in particular fresh inner gas atmosphere is supplied, in particular continuously.

[0018] This applies in particular if the heating power density of the heating device is greater than or equal to 60 kW / m2, as process-related adhesions on the metallic strip, such as rolling oils, decomposition products thereof or similar, can be vaporised, pyrolised, thermolysed or the like by the heat input . The risk of this happening increases if the metallic strip is heated quickly on a shorter heating section. For example, the metallic strip may be contaminated with a rolling oil in the course of a previous cold rolling process or the metallic strip may be contaminated with remaining components, respectively process-related adhesions in the course of a cleaning process, preferably in a cleaning section with regard to the conveyor line and / or the conveying direction upstream of the heating device, or the like .

[0019] Especially, strip adhesions in any form, like vapour, aerosol, particle, liquid, etc . and byproducts of the strip surface can be released, in particular "dissolved", in the inner gas atmosphere . This applies in particular to process-related adhesions and / or remaining components .

[0020] Insomuch, the term „used inner gas" describes an internal gas atmosphere mixed with residues of the metallic strip, in particular vaporized oil and / or aerosols and / or suspended particles, which is to be discharged from the heating zone within the meaning of the invention.

[0021] In this context, the term „fresh inner gas" describes an inner gas, which is free or at least weaken of residues of the metallic strip, in particular aerosol and / or suspended particles, or the like, that has yet to be charged to the heating zone within the meaning of the invention.

[0022] The term "fresh inner gas" can also include a renewing gas, because it could be to change the atmosphere conditions by purpose to change a redox state, to purge the atmosphere (wherein purge the atmosphere is understood as a quick replacement of an atmosphere by a new one by mean of a high gas flow rate) , or the like . Hence, fresh inner gas must not necessarily be supplied only to clean the inner gas atmosphere from strip residues .

[0023] In this respect, it may also be useful in the context of what is described here to use a charging device to supply another gas from the inner gas atmosphere . It is also conceivable that a gas discharged by a discharging device is reintroduced by means of a charging device, so that one component of the inner gas atmosphere is recirculated from outside the heating zone back to the heating zone . This gas can also be described as a recirculation gas . It is also conceivable that recirculation gas discharged outside the heating zone is first cleaned, preferably partially cleaned, before it is reintroduced to the heating zone by a charging device . Recirculation gas can help to prevent recondensing of evaporated and / or pyrolized strip revenues at the metallic strip and / or at cold parts of the heating apparatus .

[0024] A "heating zone" is understood to be the multidimensional extension of the heating apparatus, which has the inner gas atmosphere and a heating device inside .

[0025] With a view to a production line having a heating apparatus, this can also have further areas with different inner gas atmospheres, in particular an oxidation chamber and / or a reduction chamber and / or a section on an arrangement, where a reduction process occurs . In the above cases, a heating device may also be present . This is particularly the case because a predominantly isothermal atmosphere is aimed for an oxidation chamber, while the metallic strip already enters the oxidation chamber at this temperature and any heating device is only designed to maintain a largely constant temperature .

[0026] The heating power density refers to the surface area of the heating device that is arranged corresponding to the metallic strip during designated operation of the heating device and / or the heating apparatus . Specifically, in the case of an inductor, this means the surface of the inductor facing the metallic strip .

[0027] The heating power density can describe the nominal output power of the respective heating device that it is able to provide, in particular permanently.

[0028] However, even with a heating power density of less than 60 kW / m2, the heating device proposed here is advantageous, for example also from a heating power density of 5 kW / m2, 10 kW / m2, 20 kW / m2or more, as an exchange of the inner gas atmosphere can have a positive effect on the strip quality to be achieved even at such comparatively lower heating power density values .

[0029] The term „heating apparatus" describes in the meaning of the invention an electrical heating apparatus which can provide a sufficiently high electrical heating power density by means of which a metallic strip can be heated to a required temperature .

[0030] In particular, the heating apparatus can be characterised by a heating device with an induction heating element and / or an electrical resistance heating element .

[0031] A heating apparatus can have one or more heating devices, wherein a heating device can have one and more induction heating elements and / or one and more electrical resistance heating elements .

[0032] According to a preferred embodiment, the heating apparatus described here can be an additional section of a furnace for heating a metallic strip . Optionally, the heating apparatus described here can also be a separate part of a furnace for heating a metallic strip .

[0033] A "furnace" can be characterized by one and more heating apparatus . Further, a furnace can have different arrangements, in particular different heating arrangements .

[0034] A heating arrangement can have one and more sections, wherein the sections, especially different sections, can have different inner gases .

[0035] A metallic strip thickness value is generally sensitively lower than the metallic strip width value in terms of heat transfer density .

[0036] Regarding the metallic strip surface consideration, the metallic strip thickness is generally disregarded in regard to the metallic strip width. More particularly, in the case of induction heating with longitudinal heating, the metallic strip thickness is generally disregarded in regard to the metallic strip width, providing that the inductor heater has the suitable design, for example a suitable operating frequency.

[0037] A metallic strip has two main sides; thus, the surface integrates two main sides, the metallic strip being generally heated-up by means of the two main sides, more particularly for radiation heating and / or longitudinal induction heating.

[0038] If the heating device has a very high power, the power needs to be absorbed, which means the power transmission is a matter of a combination of a heating device design and the shape of a product to heat .

[0039] It is possible that induction elements of a heating device have a separate casing and / or an internal j acket, preferably supplied with nitrogen. The surrounding atmosphere can be the outside environment atmosphere, or any atmosphere of a production line, or another furnace area respective section hereof, on which the present heating apparatus is provided, for example .

[0040] The inner gas atmosphere can differ from the surrounding atmosphere in terms of its composition, temperature, pressure, pressure ratio, dew point or the like, for example .

[0041] The inner gas atmosphere can be composed differently depending on the interaction to be achieved with the metallic strip, as will be explained later .

[0042] For example, a furnace, respectively heating arrangements thereof can have several inner gas atmospheres, namely for the here described heating apparatus, for an oxidation chamber, for other sections of heating arrangements, or the like .

[0043] The heating zone can be enclosed by a housing or walls hereof for this purpose in order to ensure reliable separation of the inner gas atmosphere from the surroundings .

[0044] The term „sealing device" describes in the meaning of the invention any device through which the metallic strip can be transferred into or out the inner gas atmosphere, wherein the inner gas atmosphere can separate from a surrounding area, in particular to seal the inner atmosphere from a surrounding atmosphere around .

[0045] Such sealing devices may be used for several sections : heating section, oxidizing section, cooling section, etc . Sealing devices may be common to different sections, meaning that an outlet sealing device of one section may be the inlet sealing device of a subsequent section. Insomuch, in the meaning of the invention, the terms „inlet sealing device" and „outlet sealing device" are understood to mean a sealing device by means of which the metallic strip can be transferred into an inner gas atmosphere from the surrounding or transferred out of an inner gas atmosphere into the surrounding again.

[0046] However, an outlet sealing device, and this should be expressly pointed out here, is not an essential component for delimiting the inner gas atmosphere, in particular the inner gas atmosphere of a heating zone .

[0047] According to the first variant, it is conceivable that the inner gas atmosphere extends to a liquid bath into which the metallic strip is immersed, for example, for coating the metallic strip with the liquid or a component of the liquid. In this case, the liquid can be part of an enclosing of the heating zone . Furthermore, the inner gas atmosphere cannot escape through the liquid, or only in small quantities, so that no outlet sealing device is required next to this liquid.

[0048] According to a second variant, it is also conceivable that the heating zone is directly adj acent to an oxidation chamber or a reduction chamber, whereby the metallic strip enters through a corresponding inlet sealing device that delimits the oxidation chamber or the reduction chamber . In consequence, the heating zone does not require an outlet sealing device in this second variant either, since the corresponding functionality can be taken over by an inlet sealing device of the oxidation chamber or the reduction chamber . In other words, the inlet sealing device of an oxidation chamber or a reduction chamber can also take over the function of an outlet sealing device of a heating zone . However, according to an optional variant, the heating apparatus has an outlet sealing device for transferring the metallic strip out of the inner gas atmosphere .

[0049] Furthermore, according to another optional variant, the heating apparatus is followed by a subsequent section, which has an inlet sealing device, which acts as an outlet sealing device of the heating apparatus for transferring the metallic strip out of the inner gas atmosphere .

[0050] For example, the sealing devices, in particular an inlet sealing device and / or an outlet sealing device, are set up to allow no gas exchange between the inner gas atmosphere and the surrounding atmosphere or only a controlled gas exchange of less than or equal to 15000 1 / min, preferably less than or equal to 5000 1 / min and particularly preferably less than or equal to 2000 1 / min.

[0051] According to a preferred embodiment, the sealing devices, in particular an inlet sealing device and / or an outlet sealing device, are set up to allow no gas exchange between the inner gas atmosphere and the surrounding atmosphere or only a controlled gas exchange of less than or equal to 1500 1 / min, preferably less than or equal to 1200 1 / min or less than or equal to 900 1 / min, further preferably less than or equal to 640 1 / min or less than or equal to 400 1 / min, and particularly preferably less than or equal to 300 1 / min or less than or equal to 200 1 / min.

[0052] For example, an inlet sealing device can be regarded as tight in the sense of the invention up to about 100 m3 / h, which corresponds to about 1700 1 / min.

[0053] If, for another example, approx . 800 m3 / h of recirculation gas have to pass through a seal between a heating zone and an oxi- dation chamber of an oxidation section, this can correspond to approx . 13300 1 / min.

[0054] A sealing device can be realized in different ways, for example by means of a device for building up a „gas curtain" and / or a „physical curtain", and / or a mean for building up a pressure difference .

[0055] Sealing devices may have different forms like a device with at least one roller element for rolling on or nearby the metallic strip, and / or a device having a lip-element being in contact or very close to the metallic strip, and / or a device having a brush element being in contact or very close to the metallic strip, and / or a device having guiding rolls, and / or dampering rolls being in contact or very close to the metallic strip, a heating arrangement with a passing of the metallic strip from one section to another section, in particular a tunnel with eventually a restriction, in particular a furnace caising restriction, or the like .

[0056] A section or an equipment with a different medium and / or a different state, for example a zinc pot of a hot-dip galvanizing line, can act as a sealing device .

[0057] The term sealing device covers one or more sealing devices and / or a combination of different kinds of sealing devices .

[0058] Sealing devices can be found at different locations, especially in the case of heat treatment arrangements, where various kinds of seals for various purposes are located.

[0059] Especially in the case of an Annealing and Pickling Line with an Induction Heating Section in combination with a fossil heating a sealing is particularly advantageous . The protection of the metallic strip and the heating device can be significantly improved by reliably separating the inner gas atmosphere from the environment .

[0060] For heating or heat treatment, the metallic strip is continuously moved forward along a conveyor line in a conveying direction, whereby the section of the conveyor section at the heating zone can also be referred to as the heating section.

[0061] In this respect, the heating section can be regarded as a section of the conveyor line .

[0062] The heating section can have one or more heating zones .

[0063] In the meaning of the invention, the term „charging device" describes a device by means of which gas, in particular inner gas and / or fresh inner gas, can be charged into the heating zone and / or the inner gas atmosphere .

[0064] A charging device can be realized in different forms, for example : direct inj ection in a zone / chamber / housing through the housing wall, inj ection through sub-equipment like a pipe sight, camera sight, bearing, guiding unit, or any kind thereof .

[0065] Such a charging device can be designed in different ways, but has at least one outflow opening through which gas, in particular inner gas and / or fresh inner gas, can flow into the heating zone and / or the inner gas atmosphere .

[0066] For the purposes of the invention, the term "discharging device" describes a device by means of which used inner gas can be discharged from the heating zone and / or the inner gas atmosphere .

[0067] Such a discharging device can also be designed differently, but has at least one outlet opening through which used inner gas can be discharged out of the heating zone and / or the inner gas atmosphere .

[0068] Such a discharging device can also be further designed differently, by mean of a subsequent section where the inner gas can be discharged.

[0069] It is clear that the charging and discharging devices may have other components, such as valves, lines, pipes or other instruments or the like . However, these are not explained further here, as they are to be regarded as mandatory.

[0070] In any case, the gas changing device can be used for eliminating strip residues or for changing atmosphere conditions (change redox state, cleaning, purge (purge = quickly replace an atmosphere by a new one by mean of high gas flow) ) , or the like .

[0071] For example, if the atmosphere is clean, then the gas is not "used" but it may need to be changed to another atmosphere .

[0072] It should be noted that in the context of the present patent application, indefinite articles and indefinite numerical terms such as „one . . .", „two . . ." etc . are generally to be understood as at least indications, i . e . as „at least one . . .", „at least two . . ." etc . , unless it is clear from the context or the specific text of a particular passage that only „exactly one . . .", „exactly two . . ." etc . are meant there .

[0073] At this point it should also be mentioned that in the context of the present patent application the expression „in particular" is always to be understood as introducing an optional, preferred feature . The expression is not to be understood as „namely" .

[0074] The term „metallic strip" is used here to describe any product comprising an electrically conductive ferrous material, a steel material and / or a non-ferrous metal material . In particular, a metallic strip can be understood as any semi-finished product and / or any preliminary product and / or any intermediate product and / or any product which is electrically conductive, in particular also a metal sheet .

[0075] In particular, the metallic strip can be a rolled metal strip (rolled strip) .

[0076] The metallic strip used in the meaning of the invention has a width of greater than or equal to 200 mm, preferably of greater than or equal to 1000 mm and particularly preferably of greater than or equal to 2500 mm. Mostly, the metallic strip has a width of approximate 750 mm to 1950 mm.

[0077] It was found here that it is advantageous if the charging device is arranged in relation to the conveyor line in such a way that, in the designated operation of the heating apparatus, it is arranged in relation to the conveyor line and / or the conveying direction upstream of the point at which the designated metallic strip has a temperature on its surface below the vaporization temperature of the strip residues, in particular below the vaporization temperature of the organic compound, in particular the vaporization temperature of a rolling oil and / or the vaporization temperature of remaining components after an intermediate process like a cleaning process .

[0078] In connection with the above, it may be advantageous to arrange the discharging device in relation to the conveyor line and / or the conveying direction so that, when the heating apparatus is in operation, it is arranged in relation to the conveyor line and / or the conveying direction downstream of the point at which the vaporization of the strip residues is completed, in particular at a temperature around 400 °C to 600 °C . In further connection with the above, this can ensure that the flow of inner gas in the heating zone, which is formed as a result of the inner gas changing device replacing the inner gas atmosphere, flows in such a way that the inner gas flows in the area between the point on the metallic strip at which the vaporization of the strip residues starts and the point at which the vaporization of the strip residues is completed, in the designated conveying direction of the metallic strip in relation to the conveyor line . This can help to prevent or at least significantly reduce the condensation of evaporated strip residues on the metallic strip and / or on any cold part of the heating apparatus .

[0079] According to an optional embodiment, the heating apparatus comprises an outlet sealing device for transferring the metallic strip out of the inner gas atmosphere .

[0080] The heating apparatus can be used in a variety of ways if the heating device has a heating power density of greater than or equal to 70 kW / m2, preferably greater than or equal to 100 kW / m2or greater than or equal to 200 kW / m2, and particularly preferably greater than or equal to 1000 kW / m2, and / or a heating power density of smaller than or equal to 1500 kW / m2, preferably smaller than or equal to 200 kW / m2and particularly preferably smaller than or equal to 100 kW / m2.

[0081] Preferably the heating device features a heating power density of greater than or equal to 80 kW / m2, further preferably of greater than or equal to 90 kW / m2, further preferably of greater than or equal to 120 kW / m2, further preferably of greater than or equal to 140 kW / m2and further preferably of greater than or equal to 160 kW / m2or greater than or equal to 180 kW / m2.

[0082] Preferably the heating device has a heating power density of greater than or equal to 300 kW / m2or greater than or equal to 400 kW / m2, preferably greater than or equal to 500 kW / m2or greater than or equal to 600 kW / m2, and particularly preferably greater than or equal to 700 kW / m2or greater than or equal to 800 kW / m2. Moreover, the heating device has preferably a heating power density of greater than or equal to 900 kW / m2or greater than or equal to 1100 kW / m2, further preferably greater than or equal to 1200 kW / m2or greater than or equal to 1300 kW / m2, and particularly preferably greater than or equal to 1400 kW / m2.

[0083] Regarding to a preferred embodiment, the heating device has a heating power density of smaller than or equal to 1400 kW / m2or smaller than or equal to 1300 kW / m2, preferably smaller than or equal to 1200 kW / m2or smaller than or equal to 1100 kW / m2, and particularly preferably smaller than or equal to 1000 kW / m2or smaller than or equal to 900 kW / m2. Moreover, the heating device has preferably a heating power density of smaller than or equal to 800 kW / m2or smaller than or equal to 700 kW / m2, further preferably smaller than or equal to 600 kW / m2or smaller than or equal to 500 kW / m2, and particularly preferably smaller than or equal to 400 kW / m2or smaller than or equal to 300 kW / m2.

[0084] If the induction heating element and / or a direct resistaorheat-ing element have a sufficiently high heating power density, the heating apparatus can be used for rapid heating without any problems . In this respect, the heating apparatus can also realize a rapid heating apparatus or even a super heating apparatus .

[0085] The above-mentioned heating power density values can all be achieved particularly well using electric heating devices, especially with regard to short heating sections .

[0086] For a treatment of the metallic strip during heating, for example in a pre-heating section for rapid heating of the metallic strip to higher temperatures, it is advantageous if the inner gas atmosphere contains an inert gas component, in particular a nitrogen gas component , wherein the inner gas atmosphere has an inert gas content , in particular a nitrogen content , of greater than or equal to 0 . 2 vol . -% , preferably of greater than or equal to 98 vol . -% and particularly preferably greater than 99 , 8 vol . -

[0087] The inert gas atmosphere also can be reali zed not only by nitrogen (N2) but also by another inert gas comprising argon, helium or the like .

[0088] For other applications , the inner gas atmosphere can also be composed di f ferently .

[0089] Preferably the inner gas atmosphere has an inert gas content , in particular a nitrogen content , o f greater than or equal to 1 vol . -% or greater than or equal to 5 vol . -% , preferably of greater than or equal to 8 vol . -% or greater than or equal to 15 vol . -% , further preferably of greater than or equal to 20 vol . -% or greater than or equal to 40 vol . -% , and particularly preferably greater than or equal to 50 vol . -% or greater than or equal to 70 vol . -% . Further preferred, the inner gas atmosphere has an inert gas content , in particular a nitrogen content , of greater than or equal to 80 vol . -% , preferably of greater than or equal to 90 vol . -% or greater than or equal to 95 vol . -% , and particularly preferably equal to 100 vol . -% .

[0090] It is advantageous i f the inner gas atmosphere contains an oxidi zing component , in particular a mixture of nitrogen and oxygen, or a reducing component , in particular hydrogen or a mixture of nitrogen and hydrogen .

[0091] An oxidi z ing gas atmosphere with an oxidi zing component is characteri zed for example by a proportion of oxygen ( O2) . Such oxidi zing atmospheres are known in connection with an oxidation section for generating an oxide layer on the metallic strip . In this respect , they will not be discussed further here .

[0092] The situation is similar with the reducing gas atmosphere with a reducing component , which will be discussed insofar here , that a reducing atmosphere can help to "burn" residual components of the strip, to crack organic compounds .

[0093] An oxidi zing gas has an oxidi zing component which can have a level of 02of greater than or equal to 0 . 001 vol . -% , preferably greater than or equal to 0 . 1 vol . -% , preferably greater than or equal to 0 . 2 vol . -% .

[0094] In particular, an oxidi zing gas can have an oxidi zing component with a level of 02of greater than or equal to 0 . 5 vol . -% or greater than or equal to 0 . 7 vol . -% , preferably of greater than or equal to 1 . 2 vol . -% or greater than or equal to 1 . 5 vol . -% , further preferably of greater than or equal to 2 vol . -% or greater than or equal to 3 vol . -% , and particularly preferably of greater than or equal to 4 vol . -% or greater than or equal to 5 vol . .

[0095] Preferably an oxidi zing gas can have an oxidi zing component with a level of 02of greater less or equal to 30 vol . -% , preferably of less than or equal to 20 . 5 vol . -% , further preferably of greater less or equal to 18 vol . -% or greater than, and particularly preferably of less than or equal to 15 vol . -% .

[0096] For some applications , it can be advantageous i f the charging device is arranged with regard to the conveyor line and / or the conveying direction downstream of the discharging device .

[0097] But for the most applications of the invention it is more advantageously i f the charging device i s arranged with regard to the conveyor line, in particular the conveying direction, upstream of the discharging device .

[0098] It should be explained again at this point that a good discharge of aerosols and / or suspended particles from the inner gas atmosphere is achieved by means of the proposed inner gas changing device .

[0099] However, it is particularly advantageous if inner gas, in particular fresh inner gas, is charged to the heating zone or the inner gas atmosphere further with regard to the conveyor line and / or the conveying direction upstream and used inner gas is discharged from the heating zone or the inner gas atmosphere further downstream with regard to the conveyor line and / or the conveying direction.

[0100] This is a particularly reliable way of preventing aerosols, in particular originating from strip residues, from the heated inner gas atmosphere from condensing, for example, on the metallic strip entering the heating zone, which has not yet been sufficiently heated, and additionally accumulating. This could have a detrimental effect on the achievable quality of the metallic strip . In other words, this means that an inner gas atmosphere containing evaporated and / or pyrolyzed strip revenues, in particular aerosols and / or suspended particles, can be reliably kept away from an incoming colder metallic strip so that no additional aerosols and / or suspended particles can be deposited on the colder metallic strip, or only to a negligible extent if at all .

[0101] Furthermore, it is particularly advantageous that negative effects with regard to the accumulation and ignition of highly flammable substances in the inner gas atmosphere can be avoided. The risk of short circuits on the electrical heating devices, in particular on electrical resistance heating elements and / or induction coil heating elements, can also be prevented by this .

[0102] Further disadvantageous formation of drops can be avoided, in particular from containing aerosols and / or suspended particles, which can drip onto the metallic strip or onto guide and / or damping rollers of the conveyor section, which can adversely affect the strip quality. When the metallic strip is subj ect to a galvanization process, these quality issues further lead to zinc coating problems, leading to zinc adhesion detrimental effect, for example .

[0103] Further condensing on cold parts can be avoided as well .

[0104] Not only in this respect, but the present heating apparatus also differs significantly from the generally known heating apparatus for heating a continuously conveyed metallic strip, in which inner gas flow takes place according to the countercurrent principle .

[0105] Insomuch, the present invention departs from known solutions .

[0106] Not only the risk of condensation of evaporated and / or pyrolyzed strip revenues, in particular aerosols and / or suspended particles, be present or dissolved in the inner gas atmosphere can be significantly reduced with regard to the incoming metallic strip, but such condensation of inner gas and deposition of aerosols and / or suspended particles can also be avoided on cooler components or areas of the heating device if the charging device is arranged to the inlet side of the heating zone, in particular at or behind the inlet sealing device with regard to the conveyor line, in particular the conveying direction. Usually, the residues start evaporating at low temperature, around 150 °C to 200 °C . Hence, there is an interest of inj ection inner gas using a charging device from there .

[0107] Further along the strip travel, the strip temperature increases .

[0108] The chance of condensing on area where the temperature increases is less, thus there is an interest of feeding gas on the entry side and collecting the used gas at the end of the vaporization process .

[0109] Not only in this context, it is expedient if the charging device is arranged in particular between the inlet sealing device and the heating device .

[0110] In this respect, it is particularly expedient if the charging device is arranged with regard to the conveyor line, in particular the conveying direction, upstream of the heating device or within the heating device .

[0111] This can effectively prevent the inner gas atmosphere from condensing on the heating device itself and aerosols and / or suspended particles from settling on the heating device or its components .

[0112] This is particularly advantageous if the heating device has an actively cooled element, in particular when using inductor as heating device, for example, as the risk of unwanted condensation of the inner gas atmosphere is particularly high with an actively cooled induction heating element .

[0113] Used inner gas can be advantageously discharged from the inner gas atmosphere if the discharging device is arranged to the outlet side of the heating zone, in particular at or before, in particular upstream, the outlet sealing device with regard to the conveyor line, in particular the conveying direction.

[0114] Preferably, the discharging device is arranged between the outlet sealing device and the heating device .

[0115] In this respect, it is also advantageous if the discharging device is arranged with regard to the conveyor line downstream of the heating device in relation to the respective conveyor line, in particular the conveying direction, so that an inner gas contaminated with evaporated and / or pyrolyzed strip revenues, in particular aerosols and / or suspended particles, can also be drawn directly out of the heating zone there .

[0116] The present heating apparatus can be advantageously further developed if the inlet sealing device is arranged on the inlet side of the heating zone and an outlet sealing device is arranged at the outlet side of the heating zone .

[0117] In this respect, on the one hand the metallic strip can be transferred into the heating zone in an area of the heating apparatus, in which the charging device for charging inner gas, in particular fresh inner gas, is placed, and on the other hand the metallic strip can be transferred out the heating zone in an area of the heating apparatus, in which the discharging device for discharging used inner gas is arranged.

[0118] In addition, it is advantageous if the heating zone is delimited by a housing for separating the inner gas atmosphere from the surrounding of the heating zone, whereby the housing has the inlet sealing device . Furthermore the housing can have an outlet sealing device, which may be the inlet sealing device of another subsequent section. As already mentioned above, the heating zone can be effectively enclosed by the housing and the inner gas atmosphere can be decoupled from a surrounding atmosphere particularly safely.

[0119] In particular, the heating zone can be made accessible in a good defined manner for the metallic strip if the inlet sealing device and / or the outlet sealing device are connected to this housing.

[0120] This also allows the actual heating process on the metallic strip to be decoupled from the surrounding atmosphere .

[0121] As already mentioned above, it is advantageous if the heating apparatus has at least an electrically operating heating device .

[0122] The metallic strip can be heated in a very short heating section and in a very short time if the heating device has a direct resistance heating element, in particular if the direct resistance heating element can be heated to a temperature of greater than or equal to 850 °C, preferably greater than or equal to 1100 °C and particularly preferably greater than or equal to 1850 °C, and / or the heating device has an induction heating element .

[0123] Preferably the direct resistance heating element can be heated to a temperature of greater than or equal to 1000 °C, further preferably of greater than or equal to 1150 °C, further preferably of greater than or equal to 1200 °C, further preferably of greater than or equal to 1250 °C, further preferably of greater than or equal to 1300 °C, further preferably of greater than or equal to 1350 °C, further preferably of greater than or equal to 1400 °C, further preferably of greater than or equal to 1450 °C , further preferably of greater than or equal to 1500 °C, further preferably of greater than or equal to 1550 °C, further preferably of greater than or equal to 1600 °C, further preferably of greater than or equal to 1650 °C, further preferably of greater than or equal to 1700 °C, further preferably of greater than or equal to 1750 °C and further preferably of greater than or equal to 1800 °C .

[0124] According to a preferred embodiment, the metallic strip can be heated using at least one direct resistance heating element and / or additionally by a direct resistance heating element, which is heated electrically to a temperature of at least 800 °C, preferably 900 °C or more, for example .

[0125] Heating of the metallic strip can be achieved cumulatively or alternatively with the help of an induction heating element . An induction heating element may be a longitudinal induction heating element and / or a transversal induction heating element .

[0126] Longitudinal induction heating elements are mainly used for heating products which are featuring magnetic characteristics, or products with are featuring magnetic characteristics in a certain temperature range .

[0127] Transversal induction heating elements are mainly used for heating products which are featuring non-magnetic characteristics, or products with are featuring non-magnetic characteristics in a certain temperature range .

[0128] Particularly with regard to induction heating elements, especially if they are actively cooled, previous solutions for heating metallic strips with known furnace configurations, in particular with previously known inner gas management systems, can only be used inadequately if these induction heating elements are used to heat metallic strips to strip temperatures . These known furnace configurations cannot be adequately utilized because of evaporated and / or pyrolyzed strip revenues, in particular an aerosol-containing inner gas atmosphere can condense on colder parts, like inductor walls of an induction heating element or equipment thereof .

[0129] A lack of management of inner gas at a heating zone can significantly limit the use of induction heating technologies in particular .

[0130] With the present heating apparatus, however, such limitations can be successfully overcome, in particular by the proposed inner gas changing device .

[0131] Furthermore, it is advantageous if the heating device is set up to heat the metallic strip to a strip temperature of greater than or equal to 25 °C, preferably greater than or equal to 100 °C and particularly preferably greater than or equal to 700 °C, and / or to heat the metallic strip to a strip temperature of less than or equal to 1250 °C, preferably less than or equal to 1200 °C and particularly preferably less than or equal to 650 °C .

[0132] Preferably the heating device is set up to heat the metallic strip to a strip temperature of greater than or equal to 50 °C, further preferably to greater than or equal to 75 °C, further preferably to greater than or equal to 125 °C, further preferably to greater than or equal to 150 °C, further preferably to greater than or equal to 175 °C and further preferably to greater than or equal to 200 °C .

[0133] Moreover, the heating device is preferably set up to heat the metallic strip to a strip temperature of greater than or equal to 250 °C, further preferably to greater than or equal to 300 °C, further preferably to greater than or equal to 350 °C, further preferably to greater than or equal to 400 °C, further preferably to greater than or equal to 450 °C, further preferably to greater than or equal to 500 °C, further preferably to greater than or equal to 550 °C, further preferably to greater than or equal to 600 °C, further preferably to greater than or equal to 700 °C, further preferably to greater than or equal to 750 °C, further preferably to greater than or equal to 800 °C, further preferably to greater than or equal to 850 °C, and further preferably to greater than or equal to 900 °C .

[0134] Preferably the heating device is set up to heat the metallic strip to a strip temperature of less than or equal to 1150 °C, further preferably to less than or equal to 1100 °C, further preferably to less than or equal to 1050 °C, further preferably to less than or equal to 1000 °C, further preferably to less than or equal to 950 °C, further preferably to less than or equal to 900 °C, further preferably to less than or equal to 850 °C, further preferably to less than or equal to 800 °C, further preferably to less than or equal to 750 °C, and further preferably to less than or equal to 700 °C .

[0135] With these temperature values, the heating apparatus can be used for a wide variety of purposes .

[0136] Advantageously, the inner gas atmosphere can be set to different dew points, in particular to a dew point of greater than or equal to -50 °C, preferably greater than or equal to -40 °C and particularly preferably greater than or equal to 0 °C, and / or to a dew point of less than or equal to 20 °C, preferably less than or equal to 15 °C or less than or equal to 10 °C, and particularly preferably less than or equal to 5 °C .

[0137] Further it is advantageously if the dew point is preferably greater than or equal to -35 °C, preferably greater than or equal to -30 °C, preferably greater than or equal to -25 °C, preferably greater than or equal to -20 °C, preferably greater than or equal to -15 °C, preferably greater than or equal to -10 °C and prefer-ably greater than or equal to -5 °C . Preferably, the heating apparatus comprises a control device and / or is adapted to adjust or regulate the dew point by controlling and / or regulating with respect to the inner gas atmosphere .

[0138] In a further way, the dew point can be set by preseting the conditions of the inner gas atmosphere charging.

[0139] The heating apparatus can be operated even better if the heating apparatus is set up to feature an inner gas atmosphere pressure variation and / or pressure gradient along the conveyor line, in particular the conveying direction.

[0140] A "pressure gradient" is understood to mean a change in pressure of the inner gas atmosphere in at least one spatial direction of the heating apparatus, in particular a change in the direction of the conveyor line .

[0141] A "pressure variation" is understood to mean that different pressures of the inner gas atmosphere can be achieved at different points of the heating apparatus, e . g. a low pressure in the point of discharging which can be in the middle of the used inner gas region or which can be on the top of the furnace .

[0142] A heat treatment arrangement, in particular a heating apparatus, for example in a production line, can be built particularly compactly if the heat treatment arrangement, in particular the heating apparatus, has a heating section, in particular a quick heating section, with an active heating length of less than or equal to 80 m, preferably less than or equal to 70 m and particularly preferably less than or equal to 1 m.

[0143] Other advantageously values regarding to active heating length of the heat treatment arrangement, in particular the heating apparatus, are preferably less than or equal to 60 m, preferably less than or equal to 50 m, preferably less than or equal to 40 m, preferably less than or equal to 30 m, preferably less than or equal to 20 m, preferably less than or equal to 12 m, preferably less than or equal to 9 m, preferably less than or equal to 6 m, preferably less than or equal to 4.5 m, preferably less than or equal to 3 m, and preferably less than or equal to 1.5 m.

[0144] A range of 1.5 m to 32 m has proven itself for most applications .

[0145] A "quick heating section" means a heating section featuring an inductive heating element, which could be combined with a further heating element, in particular one or more electric radiation heating elements like electric radiant tubes .

[0146] In order to be able to collect and / or drain condensate from the heating zone safely, it is also advantageous if the heating apparatus has a separating device for separating recondensed strip revenues, in particular aerosols and / or suspended particles from the inner gas atmosphere .

[0147] It should be noted that a "separating device" is a device that can collect recondensed strip residues and / or remove them directly from the heating zone and / or from the discharging device .

[0148] Any cold piece, like an inductor frame, furnace wall, oxidation equipment (oxidation chamber) etc . can condensate the inner gas atmosphere, in particular vapors hereof . These can be fitted with collecting parts, draining parts of the separating device, wherein collecting means collecting of drops and draining means routing condensate, in particular oil, toward another device . According to a preferred embodiment, the separating device is set up to provide recondensed strip revenues for further use . In this way, they can be made available for recycling or used for thermal purposes by incineration, for example in a further section of an arrangement .

[0149] Insofar, it is suitable if the heating apparatus, in particular the separating device, has a condensing device for condensing strip revenues, in particular aerosols and / or suspended particles, and / or a draining device for draining strip revenues, in particular aerosols and / or suspended particles .

[0150] This is particularly advantageous for removing condensate liquids respectively condensate in non-gaseous state .

[0151] The condensing device could be located at a cold part of the heating apparatus, in particular cold in a designated operating state of the heating apparatus, and / or located at a cold part of an inductive heating element, in particular cold in a designated operating state of the inductive heating element .

[0152] According to a second aspect of the invention, the obj ect is achieved by a system for managing an inner gas atmosphere of an electrical heating apparatus for heating a metallic strip continuously conveyed on a conveyor line in a conveying direction, in particular on a heating apparatus, in particular on a heating apparatus described above, with a charging device for charging inner gas, in particular fresh inner gas, into the inner gas atmosphere and with a discharging device for discharging used inner gas out of the inner gas atmosphere, wherein the charging device is arranged on the conveyor line upstream with regard to the conveyor line, in particular the conveying direction, of the discharging device .

[0153] By means of such a system, aerosols and / or suspended particles of a contaminated inner gas atmosphere can be removed particularly advantageously from a heating zone of the heating apparatus, for example . It is further advantageous if the system has an inlet sealing device for transferring the metallic strip into the inner gas atmosphere and optionally has an outlet sealing device for transferring the metallic strip out of the inner gas atmosphere, wherein the charging device being arranged to and / or with regard to the conveyor line (4 ) , in particular the conveying direction (4A) , downstream the inlet sealing device and the discharging device being arranged to and / or with regard to the conveyor line (4 ) , in particular the conveying direction (4A) , upstream the optional outlet sealing device .

[0154] In this way, an exchange of inner gas atmosphere in the meaning of the invention can be carried out particularly effectively, as already explained above .

[0155] Particularly good protection against unwanted condensate in the heating device can be achieved if the charging device is arranged with regard to the conveyor line, in particular the conveying direction, upstream of the heating device or within the heating device, in particular between two heating elements, and the discharging device is arranged with regard to the conveyor line, in particular the conveying direction, downstream of the heating device or within the heating device, in particular between two heating elements .

[0156] Cumulativle or alternativle the charging device and / or discharging device can arranged within a heating device .

[0157] It is understood that in the case of several heating devices placed in series, for example, a charging device in particular can also be arranged between the heating devices . If necessary, this can also apply to a discharging device . An advantageous movement of the inner gas atmosphere can be achieved if the system is setup to feature a pressure variation and / or pressure gradient of the inner gas atmosphere between the charging device and the discharging device, wherein a higher inner gas atmospheric pressure prevails at the charging device than at the discharging device .

[0158] It should be noted here that there could be several charging devices present regarding to the system, preferably a first charging device with regard to the conveyor line and / or the conveying direction upstream of the discharging device, preferably located at the inlet sealing device and a further charging device downstream of the discharging device with regard to the conveyor line and / or the conveying direction.

[0159] In particular, several charging devices can be provided in connection with a heating arrangement as described here .

[0160] The same may apply with regard to discharging devices .

[0161] According to a preferred embodiment, the system has a separating device for separating condensed strip revenues, in particular aerosols and / or suspended particles, from the inner gas atmosphere .

[0162] At this point it should be noted that the present system can be supplemented by further features, which are explained generally or specifically in connection with the heating apparatus .

[0163] According to a third aspect of the invention, the obj ect is achieved by a production line for manufacturing and / or processing a metallic strip, in particular a semi-finished product and / or a preliminary product and / or an intermediate product and / or a product made of iron, steel and / or a non-ferrous metal material, having a conveying line along which the metallic strip is continuously conveyed in a conveying direction, and having a heating device for heating the metallic strip, wherein the production line comprises a heating apparatus and / or a system, which are explained in the context of the invention.

[0164] A production line equipped in this way can be operated significantly more effectively. This is due in particular to the fact that the individual sections of the production line and the metallic strip to be processed are much better protected against the effects of aerosol and / or suspended particles, especially condensate, more especially contaminated condensate .

[0165] In particular, the entire production line can be operated with one or more electrically powered heating apparatus, which means that the production line and in particular the section hereof can be operated complete fossil free if desired or absolutely necessary .

[0166] A heating apparatus and other heating devices can also be combined with each other in a user-specific way (annealing) , for example, which may be electric, in particular featuring electric resistor heating elements and / or induction heating elements, thus full fossil free .

[0167] Alternatively, a heating apparatus and other heating devices can also be combined with each other in a user-specific way (annealing) , for example, which may be electric, in particular featuring electric resistor heating elements and / or induction heating elements, and / or with combustion heating.

[0168] It is advantageous if the production line has a pre-heating section featuring the heating apparatus . If the pre-heating section has the heating apparatus described here, the pre-heating section can be realized particularly short .

[0169] According to a further preferred embodiment, the production line can have a first heating section for a first heating step for heating the metallic strip, upstream of the heating apparatus in the machine direction. This first heating section can also be preferably set up for heat recovery, whereby heat recovery can be understood to mean that the inner gas atmosphere discharged from the heating apparatus is supplied to the first heating section and the heat it contains can be released to the metallic strip .

[0170] The capabilities of the production line can be advantageously expanded if the production line has an oxidation section for oxidizing the metallic strip, in particular a pre-oxidation section, wherein the oxidation section has an oxidation chamber for maintaining an oxidizing atmosphere .

[0171] In addition, the oxidation section can work particularly reliably if the oxidation section has an inlet sealing device, wherein the inlet sealing device could be an outlet sealing device of a previous production line component, for example the heating apparatus, for transferring the metallic strip into the oxidizing atmosphere and an outlet sealing device, wherein the outlet sealing device could be an inlet sealing device of a with regard to the conveying line, in particular the conveying direction, downstream production line component, for transferring the metallic strip out of the oxidizing atmosphere, wherein the inlet sealing device and the outlet sealing device are arranged to and / or set up to separate the oxidizing section inner gas atmosphere from a surrounding atmosphere . It is also favorable for particularly suitable operation of the oxidation section if the oxidation section has a discharging device for discharging exhaust gas (Vout) out of the oxidizing atmosphere and a charging device for charging new oxidation gas (Vln) , in particular preheated new oxidation gas (Vln) , in particular fresh oxidation gas (Vln) , into the oxidation section.

[0172] Oxidation gas can be a mixture of air and / or oxygen balanced with neutral gas like nitrogen and / or recirculation gas from the oxidation chamber and / or a combination thereof .

[0173] The discharged exhaust gas after an oxidation reaction with the metallic strip and / or after a reaction with the H2 from the beside chambers and / or other sucked gas from other parts of the heating arrangement, in particular the heating apparatus, can be a mixture of residual oxygen and / or recirculation gas and / or used inner gas atmosphere of the heating apparatus .

[0174] Depending on the requirements for the oxidizing atmosphere, the exhaust gas (Vout) and the new gas (Vln) can be set in a ratio within a range of 0 : 1 < (Vout) / (Vln) <200 : 1.

[0175] The oxidizing atmosphere can be set with an oxygen gas content in a range between 20.5 vol . -% 02and 0.001 vol . -% O2.

[0176] According to a preferred embodiment, an oxidizing atmosphere can be set with an oxygen gas content of greater than or equal to 0.1 vol . -%, preferably greater than or equal to 0.2 vol . -%, preferably greater than or equal to 0.5 vol . -% .

[0177] In particular, an oxidizing gas can have an oxidizing component with a level of O2of greater than or equal to 0.7 vol . -%, preferably of greater than or equal to 1.2 vol . -% or greater than or equal to 1.5 vol . -%, further preferably of greater than or equal to 2 vol . -% or greater than or equal to 3 vol . -%, and particularly preferably of greater than or equal to 4 vol . -% or greater than or equal to 5 vol . -% .

[0178] Optional, an oxidizing gas can have an oxidizing component with a level of 02of greater less or equal to 20.5 vol . -%, preferably of less than or equal to 18 vol . -%, further preferably of greater less or equal to 15 vol . -% or greater than, and particularly preferably of less than or equal to 10 vol . -% .

[0179] If heating apparatus inner gas is recirculated in the heating apparatus, via a specific circuity and / or via the oxidation chamber, the ratio of fresh inner gas vs . recirculation gas can varies from 0 : 1 (Full recirculation) to 1 : 0 (Full fresh gas) .

[0180] A pressure difference [relative pressure or absolute pressure or pressure difference, which is the use case here] between the oxidation chamber and the other parts of the heating arrangement and / or heating device can be altered by changing the supply mass flow of the oxidizing gas mixture or by changing the suction capacity of the oxidation chamber extraction system.

[0181] The oxidation section can be operated even more efficiently and advantageously if the oxidation section is arranged with regard to the conveying line, in particular the conveying direction, downstream of a pre-heating section.

[0182] Furthermore, the production line can be advantageously designed if the production line has an annealing section, wherein in particular the annealing section is arranged with regard to the conveyor line, in particular the conveying direction, downstream of a pre-heating section and / or an oxidation section.

[0183] The application of the production line can be advantageously extended if the production line has a soaking section, wherein in particular the soaking section is arranged with regard to the conveyor line, in particular the conveying direction, downstream of a pre-heating section and / or downstream of an oxidation section and / or downstream of an annealing section.

[0184] The treatment options for the metallic strip can be further expanded on the production line if the production line has a cooling section, wherein in particular the cooling section is arranged with regard to the conveyor line, in particular the conveying direction, downstream of a pre-heating apparatus, and / or downstream of an oxidizing section, and / or downstream of an annealing section and / or downstream of a soaking section.

[0185] The invention regards in particularly to the following types of production lines or heating arrangements hereof :

[0186] - Continuous annealing line (CAL)

[0187] - Continuous galvanizing line (CGL)

[0188] (Continuous) Pickling and galvanizing line (PGL) (Continuous) Annealing and coating line (ACL) (Continuous) Annealing and pickling line (APL) (Continuous) Bright annealing line (BAL)

[0189] In particularly in regard to following types of steels :

[0190] - Carbon steel

[0191] - Stainless steel

[0192] - Silicon steel

[0193] According to a fourth aspect of the invention, the obj ect is achieved by a method for heating a metallic strip continuously conveyed on a conveyor line, wherein the metallic strip is continuously conveyed through a heating zone charged with an inner gas atmosphere, wherein the metallic strip is heated within the heating zone with a heating power density of in particular greater than or equal to 60 kW / m2, wherein fresh inner gas is charged into the heating zone with regard to the conveyor line, in particular the conveying direction, upstream of a discharging of used inner gas out of the heating zone .

[0194] Using the method proposed here, the operational safety of an electrically operated heating apparatus can be significantly improved. Moreover, the efficiency of the strip processing can be increased and / or a number of any unwanted defects that may occur on a treated metallic strip can be reduced.

[0195] This applies in particular with the heating power density as already explained here .

[0196] The method can be used in a variety of ways with a heating power density of greater than or equal to 70 kW / m2, preferably greater than or equal to 100 kW / m2or greater than or equal to 200 kW / m2, and particularly preferably greater than or equal to 1000 kW / m2, and / or a heating power density of smaller than or equal to 1500 kW / m2, preferably smaller than or equal to 200 kW / m2and particularly preferably smaller than or equal to 100 kW / m2.

[0197] Preferably the method can be operated with a heating power density of greater than or equal to 300 kW / m2, further preferably of greater than or equal to 400 kW / m2, further preferably of greater than or equal to 500 kW / m2, further preferably of greater than or equal to 600 kW / m2, further preferably of greater than or equal to 700 kW / m2, further preferably of greater than or equal to 800 kW / m2, further preferably of greater than or equal to 900 kW / m2, further preferably of greater than or equal to 1000 kW / m2, further preferably of greater than or equal to 1100 kW / m2, further preferably of greater than or equal to 1200 kW / m2, further preferably of greater than or equal to 1300 kW / m2and further preferably of greater than or equal to 1400 kW / m2. Further it is advantageously, if the heating power density is smaller than or equal 3000 kW / m2to avoid excessively massive heating devices .

[0198] The metallic strip maybe more narrow, thus possibly higher density, but the power will be limited by the inductor current / volt-age limits .

[0199] However, even with a heating power density of less than 60 kW / m2, the heating device proposed here is advantageous, for example also from a heating power density of 5 kW / m2, 10 kW / m2, 20 kW / m2or more, as an exchange of the inner gas atmosphere can have a positive effect on the strip quality to be achieved even at such comparatively lower heating power density values .

[0200] A further developed method variant provides that the charge of inner gas, in particular fresh inner gas, takes place upstream with regard to the conveyor line, in particular the conveying direction, of the electrical heating device or within the electrical heating device and the discharging of used inner gas takes place downstream with regard to the conveyor line, in particular the conveying direction, of the electrical heating device or within the electrical heating device .

[0201] The settling of condensate in cooler areas within the heating apparatus can be prevented particularly effectively if the charge of inner gas, in particular fresh inner gas, takes place at or after an inlet sealing device for transferring the metallic strip into the heating zone and the discharge of used inner gas takes place at or after an outlet sealing device for transferring the metallic strip out of the heating zone .

[0202] The heating zone of the heating apparatus can be flowed particularly well with new inner gas if an inner gas atmospheric pressure of the inner gas atmosphere upstream with regard to the conveyor line, in particular the conveying direction, of the electrical heating device is set higher than an inner gas atmospheric pressure downstream with regard to the conveyor line, in particular the conveying direction, of the electrical heating device .

[0203] The proposed method can be further developed if the metallic strip is heated within the inner gas atmosphere to a strip temperature of greater than or equal to 25 °C, preferably greater than or equal to 100 °C and particularly preferably greater than or equal to 700 °C, and / or to a strip temperature of less than or equal to 1250 °C, preferably less than or equal to 1200 °C and particularly preferably less than or equal to 650 °C .

[0204] With these temperature values, the heating apparatus can be used for a wide variety of purposes .

[0205] The situation is similar if the dew point of the inner gas atmosphere is set up to a value of greater than or equal to -50 °C, preferably greater than or equal to -40 °C and particularly preferably greater than or equal to 0 °C, and / or is set up to a value of less than or equal to 20 °C, preferably less than or equal to 15 °C or less than or equal to 10 °C and particularly preferably less than or equal to 5 °C .

[0206] The dew point can be set, in particular, by controlling and / or regulating the inner gas atmosphere .

[0207] In a further way, the dew point can be set by presetting the conditions of the inner gas atmosphere charging.

[0208] The method can be made even more precise, if the dew point at the production line is set up to one of the above values, in particularly in a section of the production line and / or in one of the heating arrangements of the production line, preferably in the heating zone, and / or in an annealing section and / or in a soaking section and / or in a cooling section and / or in an over-aging section and / or in a furnace exit zone, preferably with regard to the conveyor line, in particular the conveying direction, upstream of a zinc pot .

[0209] The procedure can be adapted to changing operational requirements ( for example heat treatment requirements) without interruption if the gas conditions regarding the inner gas atmosphere can be changed during operation, in particular regarding to a gas composition, a gas temperature, a dew point, a strip characteristics, an operation condition of any former process and / or the like .

[0210] The term "gas composition" includes for example oxidation / re-duction characteristics, dew point, the concentration of "aerosol" or the like .

[0211] According to a preferred embodiment, an oxidation layer is reduced by using a reducing atmosphere .

[0212] Preferably, the oxidation layer has been build in an oxidation chamber and / or an oxidation section. Thus, the reduction of the oxidation layer on the metallic strip takes place after the metallic strip has passed the oxidation chamber and / or the oxidation section, in particular within the annealing section and / or the soaking section.

[0213] Furthermore, as required the inner gas atmosphere can be adjusted by gas inj ection in at least two separate areas by using either different gas mixtures and / or different gas flows and / or by arranging different inlet pressures .

[0214] Additionally, at least two pressure zones can be defined within a treatment arrangement or a heating arrangement . For example, a pressure at an inlet of a pre-heating section (pl ) , a pressure at an inlet of an annealing / oxidation section (p2 ) and a pressure of a through-heating section (p3) .

[0215] The pressure can vary depending on the need.

[0216] For galvanization line there is a need of discharging part of the gases close zinc pot area, while the remaining gas can be discharged at other locations .

[0217] Various pressure zones can be defined: inlet and / or outlet of pre-heating section, oxidation section, any section of the heating arrangement like annealing section, soaking section, cooling section, section close to zinc hot-dip, etc .

[0218] In particular, the pressure difference between an oxidation section and the other parts of the heating arrangement can be altered by changing the supply flow of the oxidizing gas mixture, in particular the mass flow and / or the volume flow of of the oxidizing gas mixture, and / or by changing the suction capacity of an extraction system.

[0219] The method proposed here is particularly suitable for operating the heating apparatus described here .

[0220] At this point, it is also claimed that the method described can also be supplemented by further technical features described here, in particular by features of the heating device, in order to further develop the method advantageously or to be able to represent or formulate method specifications even more precisely.

[0221] Further advantages, details and features of the invention can also be seen from the examples of embodiments explained below. Components which are at least substantially identical in the individual figures with regard to their function may be marked with the same reference signs, whereby the components need not be numbered and explained in all figures .

[0222] The drawing shows :

[0223] Figure 1 : schematic view of a first example of a heating apparatus of a pre-heating section of a production line for manufacturing and / or processing a metallic strip;

[0224] Figure 2 : schematic view of a second example of another heating apparatus of a pre-heating section of a production line for manufacturing and / or processing a metallic strip;

[0225] Figure 3 : schematic view of a heating arrangement for a hot-dip galvanizing line for galvanizing a metallic strip;

[0226] Figure 4 : schematic view of another heating arrangement for a hot-dip galvanizing line for galvanizing a metallic strip; and

[0227] Figure 5 : schematic view of a further heating arrangement for a further production line for manufacturing and / or processing a metallic strip .

[0228] According to Figure 1, a first example of a heating apparatus 1 for heating a metallic strip 2 is shown, wherein the metallic strip 2 is continuously conveyed on a conveyor line 4 in conveying direction 4A. The conveyor line 4 defines a conveyor plane 4B .

[0229] The conveyor line 4 is part of a production line 6 for manufacturing and / or processing the metallic strip 2, wherein the production line 6 is not shown further . The heating apparatus 1 has a heating zone 8 with a heating section 8A, wherein the metallic strip 2 can be heated in the heating zone 8 .

[0230] The heating section 8A has an active heating length 8B of 20 m, wherein the heating section 8A is part of the conveyor line 4.

[0231] The heating zone 8 is covered by a housing 10 to separate an inner gas atmosphere 12 from any surrounding atmosphere 14.

[0232] The inner gas atmosphere 12 of the heating apparatus 1 is an inert atmosphere comprising nitrogen, in particular to protect the heated metallic strip 2 from undesirable chemical reactions .

[0233] The heating apparatus 1 comprises two heating devices 16A and 16B, wherein the two heating devices 16A and 16B have induction heating elements 16C . The two heating devices 16A and 16B are placed into inert atmosphere in order to protect them as well from undesirable chemical reactions .

[0234] The heating devices 16A and 16B each have a heating power density of 1200 kW / m2.

[0235] The heating apparatus 1 comprises an inlet sealing device 18 for transferring the metallic strip 2 into the inner gas atmosphere 12, and an outlet sealing device 20 for transferring the metallic strip 2 out of the inner gas atmosphere 12.

[0236] Both, the inlet sealing device 18 and the outlet sealing device 20 have sealing elements, such as sealing rolls 22 shown here as an example, to prevent critical gas exchange between the inner gas atmosphere 12 and the surrounding atmosphere 14. Furthermore, the heating apparatus 1 has an inner gas changing device 24 having, in this first example, two charging devices 24A for charging fresh inner gas 12A into the heating zone 8 and having a discharging device 24B for discharging used inner gas 12B out of the heating zone 8.

[0237] As can be seen the charging devices 24A are arranged with regard to the conveyor line 4, in particular the conveying direction (4A) , upstream of the discharging device 24B .

[0238] The first charging device 24A of the two charging devices 24A is arranged on the inlet side 26 of the heating apparatus 1, in particular of the heating zone 8, and the second charging device 24A of the two charging devices 24A is arranged between the two heating devices 16A and 16B .

[0239] The discharging device 24B is arranged on the outlet side 28 of the heating apparatus 1, in particular of the heating zone 8.

[0240] If necessary, a discharging device 24B can also be placed between two heating devices 16A and 16B .

[0241] The inner gas changing device 24, in particular the discharging device 24B hereof, has a preferably water-cooled gas line 30 for condensing aerosol and / or suspended particles, as oil for example or the like, from the used inner gas 12B .

[0242] The gas line 30 comprises a drain device 32 for oil for example and the final air extraction device 34.

[0243] In this respect, the heating apparatus 1 is equipped with an advantageous system 40 for managing an inner gas atmosphere 12 which can also be used advantageously without this specific heating apparatus 1 at any area of the production line 6. According to Figure 2, another heating apparatus 100 is shown.

[0244] The other heating apparatus 100 (Figure 2 ) is similar to the first heating apparatus 1 shown in Figure 1, although not all features of the first heating apparatus 1 are shown in relation to the other heating apparatus 100.

[0245] The other heating apparatus 100 is equipped with the system 40, but the system 40 is not shown in figure 2.

[0246] Anyway, only the different features relating to the other heating device 100 are explained below.

[0247] The other heating apparatus 100 has a separating device 36 for separating aerosols and / or suspended particles, in particular evaporated oil, from the inner gas atmosphere 12.

[0248] This separating device 36 has a condensing device 36A for condensing aerosols and / or suspended particles from the inner gas atmosphere 12 .

[0249] Further the separating device 36 has a draining device 36B for draining the condensate, in particular for aerosols and / or suspended particles, wherein these condensates can be disposed of by means of a condensate discharge system 36C, in particular to make it available for recycling.

[0250] The draining device 36B has troughs and / or collection trays, for example .

[0251] According to Figure 3, a first heating arrangement 50 for a hot-dip galvanizing line 6A is shown, wherein the heating arrangement 50 comprises a pre-heating section 52, an oxidation section 54, and a soaking section 56. The heating arrangement 50 can also be enclosed by a casing 58.

[0252] The heating arrangement 50 has an input side 60 on which the metallic strip 2 is fed and an output side 62 on which the metallic strip 2 is passed on to a zinc bath (not shown) of the hot-dip galvanizing line 6A.

[0253] The pre-heating section 52, the oxidation section 54, and the soaking section 56 may be equipped with the heating apparatus 1, 100 and / or the system 40 of the invention.

[0254] The oxidation section 54 has an oxidation chamber 54A for maintaining an oxidizing atmosphere 54B .

[0255] The oxidation section 54 has an inlet sealing device 18, 22 for transferring the metallic strip 2 into the oxidizing gas atmosphere 12 and an outlet sealing device 20, 22 for transferring the metallic strip 2 out of the oxidizing gas atmosphere 12, wherein the inlet sealing device 8, 22 and the outlet sealing device 20, 22 are arranged to separate the oxidizing gas atmosphere 12 from a surrounding atmosphere 14.

[0256] The oxidation section 54 can have an additional circulation device 64 with a discharging device 64B for discharging exhaust gas 12B (Vout) out of the oxidizing gas atmosphere 54Band a charging device 64A for charging oxidation chamber inner gas 12A (Vln) , in particular fresh oxidation chamber inner gas 12A, in particular preheated oxidation chamber inner gas 12A (Vln) , in particular preheated fresh oxidation chamber inner gas 12A (Vln) , into the oxidizing gas atmosphere 12.

[0257] According to Figure 4, another heating arrangement 70 for a hot-dip galvanizing line 6A is shown, wherein the other heating arrangement 70 comprises a pre-heating section 52, an oxidation section 54, an oxidation chamber 54A, and a soaking section 56, as well .

[0258] As the other heating arrangement 70 differs from the first heating arrangement 50 by a differently constructed oxidation section 54, whereby the differently constructed oxidation section 54 has a u-shaped strip guide 72 for guiding the metallic strip through the differently constructed oxidation section 54.

[0259] Otherwise, reference is made to the explanations of the first heating arrangement 1 .

[0260] According to Figure 5, a further heating arrangement 80 is shown for a further production line 6B .

[0261] The further heating arrangement 80 has four different regions resp . four treatment regions, namely pre-heating section 52, an annealing section 82, a pre-oxidation section 54, a cooling section 84, wherein different sections have different pressures pl, p2 and p3 for example, where are related as follows : pl > p3 > p2 .

[0262] In this example (Figure 5) , the pressure pl is more around the inlet of the pre-heating section 52, while the pressure p2 is more in the area between the pre-heating section 52 and the annealing section 82, or more precisely at the outlet sealing device 20.

[0263] The pressure p3 is applied in the annealing section 82, wherein the annealing section 82 can often also be referred to as a through-heating section. The annealing section 82 and the cooling section 84 may be equipped with the heating apparatus 1, 100 and / or the system 40 of the invention.

[0264] At this point it should be pointed out once again that all sections 52, 54, 56, 82, 84 and even more sections can be equipped with at least one heating apparatus 1, 100 and / or with at least one system 40 described here, if this is advantageous .

[0265] In this respect, heating apparatus 1, 100 and components hereof on the one hand and system 40 and components hereof on the other hand can be installed once or several times on each of the heating arrangements 50, 70, 80 and each of the production lines 6, 6A, 6B .

[0266] At this point, it should be explicitly pointed out that the features of the solutions described above or in the claims and / or figures can also be combined, if necessary in order to be able to implement or achieve the features, effects and advantages . Reference sign list

[0267] 1 heating apparatus

[0268] 2 metallic strip

[0269] 4 conveyor line

[0270] 4A conveying direction

[0271] 4B conveyor plane

[0272] 6 production line

[0273] 6A hot-dip galvanizing line

[0274] 6B further production line

[0275] 8 heating zone

[0276] 8A heating section

[0277] 8B active heating length

[0278] 10 housing

[0279] 12 inner gas atmosphere

[0280] 12A inner gas, in particular fresh inner gas

[0281] 12B used inner gas

[0282] 14 surrounding atmosphere

[0283] 16A first heating device

[0284] 16B second heating device (optional)

[0285] 16C induction heating element (s)

[0286] 18 inlet sealing device

[0287] 20 outlet sealing device

[0288] 22 sealing element, sealing roll (s) , sealing device 24 inner gas changing device

[0289] 24A charging devices

[0290] 24B discharging device

[0291] 26 inlet side

[0292] 28 outlet side

[0293] 30 gas line

[0294] 32 drain device

[0295] 34 air extraction device

[0296] 36 separating device

[0297] 36A condensing device

[0298] 36B draining device 36C discharge system, preferably condensate discharge system

[0299] 40 System for managing an inner gas atmosphere

[0300] 50 first heating arrangement

[0301] 52 pre-heating section

[0302] 54 oxidation section or pre-oxidation section

[0303] 54A oxidation chamber

[0304] 54B oxidation chamber inner gas atmosphere

[0305] 56 soaking section

[0306] 58 casing

[0307] 60 input side

[0308] 62 output side

[0309] 64 additional circulation device

[0310] 64A charging device

[0311] 64B discharging device

[0312] 70 another heating arrangement

[0313] 72 u-shaped strip guide

[0314] 80 further heating arrangement

[0315] 82 annealing section

[0316] 84 cooling section

[0317] 100 another heating apparatus

Claims

1. Claims2.1 . Heating apparatus ( 1 , 100 ) for heating a metallic strip ( 2 ) continuously conveyed on a conveyor line ( 4 ) comprising :3.• a heating device ( 16A, 16B ) , in particular wherein the heating device ( 16A, 16B ) has a heating power density of greater than or equal to 60 kW / m2,4.• a heating zone ( 8 ) having an inner gas atmosphere ( 12 ) , wherein the heating device ( 16A, 16B ) is arranged,5.an inlet sealing device ( 18 ) for trans ferring the metallic strip ( 2 ) into the inner gas atmosphere ( 12 ) , and6.• an inner gas changing device ( 24 ) having a charging device ( 24A) for charging inner gas ( 12A) , in particular fresh inner gas ( 12A) , into the heating zone ( 8 ) and having a discharging device ( 24B ) for discharging used inner gas ( 12B ) out of the heating zone ( 8 ) .7.2 . Heating apparatus ( 1 , 100 ) according to claim 1 , characterized in that the heating apparatus ( 1 , 100 ) has an outlet sealing device ( 20 ) for trans ferring the metallic strip ( 2 ) out of the inner gas atmosphere ( 12 ) .8.3 . Heating apparatus ( 1 , 100 ) according to one of the claims 1 or 2 , characterized in that the heating device ( 16A, 16B ) has a heating power density of greater than or equal to 70 kW / m2, preferably greater than or equal to 100 kW / m2or greater than or equal to 200 kW / m2, and particularly preferably greater than or equal to 1000 kW / m2, and / or a heating power density of smaller than or equal to 1500 kW / m2, preferably smaller than or equal to 200 kW / m2and particularly preferably smaller than or equal to 100 kW / m2. 4 . Heating apparatus ( 1 , 100 ) according to one of the claims 1 to 3 , characterized in that the inner gas atmosphere ( 12 ) contains an inert gas component , in particular a nitrogen gas component , wherein the inner gas atmosphere has an inert gas content of greater than or equal to 0 . 2 vol . -% , preferably of greater than or equal to 98 vol . -% and particularly preferably greater than 99 , 8 vol . -% .9.5 . Heating apparatus ( 1 , 100 ) according to one of claims 1 to 4 , characterized in that the inner gas atmosphere ( 12 ) contains an oxidi zing component , in particular a mixture of nitrogen and oxygen, or a reducing component , in particular a mixture of nitrogen and hydrogen .10.6 . Heating apparatus ( 1 , 100 ) according to one of claims 1 to 5 , characterized in that the charging device ( 24A) is arranged with regard to the conveyor line ( 4 ) , in particular the conveying direction ( 4A) , upstream of the discharging device ( 24B ) .11.7 . Heating apparatus ( 1 , 100 ) according to one of claims 1 to 6 , characterized in that the charging device ( 24A) is arranged to the inlet side ( 26 ) of the heating zone ( 8 ) , in particular at or behind the inlet sealing device ( 18 ) with regard to the conveyor line ( 4 ) , in particular the conveying direction ( 4A) .12.8 . Heating apparatus ( 1 , 100 ) according to one of claims 1 to 7 , characterized in that the charging device ( 24A) is arranged with regard to the conveyor line ( 4 ) , in particular the conveying direction ( 4A) , upstream the heating device ( 16A, 16B ) or within the heating device ( 16A, 16B ) .13.9 . Heating apparatus ( 1 , 100 ) according to one of claims 1 to 8 , characterized in that the discharging device ( 24B ) is arranged to the outlet side ( 28 ) of the heating zone ( 8 ) , in particular at or before the outlet sealing device ( 20 ) with regard to the conveyor line ( 4 ) , in particular the conveying direction ( 4A) .

10. Heating apparatus ( 1, 100) according to one of claims 1 to 9, characterized in that the discharging device (24B) is arranged with regard to the conveyor line (4 ) , in particular the conveying direction (4A) , downstream the heating device ( 16A, 16B) .

11. Heating apparatus ( 1, 100) according to one of claims 1 to 10, characterized in that the inlet sealing device ( 18 ) is arranged at an inlet side (26) of the heating zone ( 8 ) and the outlet sealing device (20) is arranged at the outlet side (28 ) of the heating zone ( 8 ) .

12. Heating apparatus ( 1, 100) according to one of claims 1 to 11, characterized in that the heating zone ( 8 ) is delimited by a housing ( 10) for separating the inner gas atmosphere ( 12 ) from the surrounding ( 14 ) of the heating zone ( 8 ) , wherein the housing ( 10) features the inlet sealing device ( 18 ) and can preferably feature an outlet sealing device (20) .

13. Heating apparatus ( 1, 100) according to one of claims 1 to 12, characterized in that the heating device ( 16A, 16B) has a direct resistance heating element, preferably wherein the direct resistance heating element is set up to be heated to a temperature of higher than or equal to 850 °C, preferably of higher than or equal to 1100 °C, and particularly preferably of higher than or equal to 1850 °C, and / or the heating device ( 16A, 16B) has an induction heating element ( 16C) .

14. Heating apparatus ( 1, 100) according to one of claims 1 to 13, characterised in that heating device ( 16A, 16B) is set up to heat the metallic strip (2 ) to a strip temperature of greater than or equal to 25 °C, preferably greater than or equal to 100 °C, and particularly preferably greater than or equal to 700 °C, and / or to heat the metallic strip (2 ) to a strip temperature of less than or equal to 1250 °C, preferably less than or equal to 1200 °C, and particularly preferably less than or equal to 650 °C .

15. Heating apparatus ( 1, 100) according to one of claims 1 to 14, characterised in that the inner gas atmosphere ( 12 ) can be set to different dew points, in particular to a dew point of greater than or equal to -50 °C, preferably greater than or equal to -40 °C and particularly preferably greater than or equal to 0 °C, and / or to a dew point of less than or equal to 20 °C, preferably less than or equal to 15 °C or less than or equal to 10 °C and particularly preferably less than or equal to 5 °C .

16. Heating apparatus ( 1, 100) according to one of claims 1 to 15, characterised in that the heating apparatus ( 1, 100) is set up to feature an inner gas atmosphere ( 12 ) pressure variation and / or pressure gradient along the conveyor line (4 ) , in particular the conveying direction (4A) .

17. Heating apparatus ( 1, 100) according to one of claims 1 to 16, characterised in that the heating apparatus ( 1, 100) has a heating section ( 8A) , in particular a quick heating section, with an active heating length ( 8B) of less than or equal to 80 m, preferably less than or equal to 70 m and particularly preferably less than or equal to 1 m.

18. Heating apparatus ( 1, 100) according to one of claims 1 to 17, characterised in that the heating apparatus ( 1, 100) has a separating device (36) for separating recondensed strip revenues, in particular aerosols and / or suspended particles, from the inner gas atmosphere ( 12 ) .

19. Heating apparatus ( 1, 100) according to claim 18, characterised in that the separating device (36) is set up to provide recondensed strip revenues for further use .

20. Heating apparatus ( 1, 100) according to one of the claims 18 or 19, characterised in that the heating apparatus ( 1, 100) , in particular the separating device (36) , has a condensing device (36A) for condensing strip revenues, in particular aerosols and / or suspended particles, and / or a draining device (36B) fordraining recondensed strip revenues , in particular aerosols and / or suspended particles .23.21 . System ( 40 ) for managing an inner gas atmosphere ( 12 ) of an electrical heating apparatus ( 1 , 100 ) for heating a metallic strip ( 2 ) continuously conveyed on a conveyor line ( 4 ) in a conveying direction ( 4A) , in particular on a heating apparatus ( 1 , 100 ) , in particular according to one of the preceding claims , with a charging device ( 24A) for charging inner gas ( 12A) , in particular fresh inner gas ( 12A) , into the inner gas atmosphere ( 12 ) and with a discharging device ( 24B ) for discharging used inner gas ( 12B ) out of the inner gas atmosphere ( 12 ) , wherein the charging device ( 24A) is arranged on the conveyor line ( 4 ) upstream with regard to the conveyor line ( 4 ) , in particular the conveying direction ( 4A) , of the discharging device ( 24B ) .24.22 . System ( 40 ) according to claim 21 , characterised in that the system ( 40 ) has an inlet sealing device ( 18 ) for trans ferring the metallic strip ( 2 ) into the inner gas atmosphere ( 12 ) and an outlet sealing device ( 20 ) for trans ferring the metallic strip ( 2 ) out of the inner gas atmosphere ( 12 ) , wherein the charging device ( 24A) being arranged to and / or with regard to the conveyor line ( 4 ) , in particular the conveying direction ( 4A) , downstream the inlet sealing device ( 18 ) and the discharging device ( 24B ) being arranged to and / or with regard to the conveyor line ( 4 ) , in particular the conveying direction ( 4A) , upstream the outlet sealing device ( 20 ) .25.23 . System ( 40 ) according to claim 21 or 22 , characterised in that the charging device ( 24A) is arranged with regard to the conveyor line ( 4 ) , in particular the conveying direction ( 4A) , upstream of the heating device ( 16A, 16B ) or within the heating device ( 16A, 16B ) and the discharging device ( 24B ) is arranged with regard to the conveyor line ( 4 ) , in particular the conveying direction ( 4A) , downstream of the heating device ( 16A, 16B ) or within the heating device ( 16A, 16B ) .

24. System (40) according to one of claims 21 to 23, characterised in that the system (40) is setup to feature a pressure variation and / or pressure gradient of the inner gas atmosphere ( 12 ) between the charging device (24A) and the discharging device (24B) , wherein a higher inner gas atmospheric pressure prevails at the charging device (24A) than at the discharging device (24B) .

25. System (40) according to one of claims 21 to 24 , characterised in that the system (40) has a separating device (36) for separating recondensed strip revenues, in particular aerosols and / or suspended particles, from the inner gas atmosphere ( 12 ) .

26. Production line ( 6, 6A, 6B) for manufacturing and / or processing a metallic strip (2 ) , in particular a semi-finished product and / or a preliminary product and / or an intermediate product and / or a product made of iron, steel and / or a non-ferrous metal material, having a conveying line (4 ) along which the metallic strip (2 ) is continuously conveyed in a conveying direction (4A) , and having a heating device ( 16A, 16B) for heating the metallic strip (2 ) , characterised in that the production line ( 6, 6A, 6B) comprises a heating apparatus ( 1, 100) according to one of claims 1 to 20 and / or a system (40) according to one of claims 21 to 25.

27. Production line ( 6, 6A, 6B) according to claim 26, characterised in that the production line ( 6, 6A, 6B) has a preheating section (52 ) featuring the heating apparatus ( 1, 100) .

28. Production line ( 6, 6A, 6B) according to claim 26 or 27, characterised in that the production line ( 6, 6A, 6B) has an oxidation section (54 ) for oxidizing the metallic strip (2 ) , in particular a pre-oxidation section, wherein the oxidation section (54 ) has an oxidation area (54A) for setting an oxidizing section inner gas atmosphere .29 . Production line ( 6 , 6A, 6B ) according to claim 28 , characterised in that the oxidation section ( 54 ) has an inlet sealing device ( 18 , 22 ) for trans ferring the metallic strip ( 2 ) into the oxidi zing atmosphere ( 12 ) and an outlet sealing device ( 20 , 22 ) for trans ferring the metallic strip ( 2 ) out of the oxidi zing atmosphere ( 12 ) , wherein the inlet sealing device ( 18 , 22 ) and the outlet sealing device ( 20 , 22 ) are arranged to and / or set up to separate the oxidi zing section inner gas atmosphere from a surrounding atmosphere .30.30 . Production line ( 6 , 6A, 6B ) according to one of claims 28 or 29 , characterised in that the oxidation section ( 54 ) has a discharging device for discharging exhaust gas (Vout) out of the oxidi zing atmosphere and a charging device for charging new oxidation gas (Vln) , in particular preheated new oxidation gas (Vln) , in particular fresh oxidation gas (Vln) , into the oxidation section ( 54 ) .31.31 . Production line ( 6 , 6A, 6B ) according to one of claims 28 to 30 , characterised in that the oxidation section ( 54 ) is arranged with regard to the conveying line ( 4 ) , in particular the conveying direction ( 4A) , downstream of a pre-heating section ( 52 ) .32.32 . Production line ( 6 , 6A, 6B ) according to one of claims 26 to 31 , characterised in that the production line ( 6 , 6A, 6B ) has an annealing section ( 82 ) , wherein in particular the annealing section ( 82 ) is arranged with regard to the conveyor line ( 4 ) , in particular the conveying direction ( 4A) , downstream of a preheating ( 52 ) section and / or an oxidation section ( 54 ) .33.33 . Production line ( 6 , 6A, 6B ) according to one of claims 26 to 32 characterised in that the production line ( 6 , 6A, 6B ) has a soaking section ( 56 ) , wherein in particular the soaking section ( 56 ) is arranged with regard to the conveyor line ( 4 ) , in particular the conveying direction ( 4A) , downstream of a pre-heat- ing section ( 52 ) and / or downstream of an oxidation section ( 54 ) and / or downstream of an annealing section ( 82 ) .34.34 . Production line ( 6 , 6A, 6B ) according to one of claims 26 to 33 , characterised in that the production line ( 6 , 6A, 6B ) has a cooling section ( 84 ) , wherein in particular the cooling section ( 84 ) is arranged with regard to the conveyor line ( 4 ) , in particular the conveying direction ( 4A) , downstream of a pre-heating section ( 52 ) and / or downstream of an oxidi zing section ( 54 ) , and / or downstream of an annealing section ( 82 ) and / or downstream of a soaking section ( 56 ) .35.35 . Method for heating a metallic strip ( 2 ) continuously conveyed on a conveyor line ( 4 ) , wherein the metallic strip ( 2 ) is continuously conveyed through a heating zone ( 8 ) charged with an inner gas atmosphere ( 12 ) , wherein the metallic strip ( 2 ) is heated within the heating zone ( 8 ) by means of an electrical heating device ( 16A, 16B ) with a heating power density of in particular greater than or equal to 60 kW / m2, wherein inner gas ( 12A) , in particular fresh inner gas ( 12A) , is charged into the heating zone ( 8 ) with regard to the conveyor line ( 4 ) , in particular the conveying direction ( 4A) , upstream of a discharging of used inner gas out of the heating zone ( 8 ) .36.36 . Method according to claim 35 , characterised in that the charge of inner gas ( 12A) , in particular fresh inner gas ( 12A) , takes place upstream with regard to the conveyor line ( 4 ) , in particular the conveying direction ( 4A) , of the electrical heating device ( 16A, 16B ) or within the electrical heating device ( 16A, 16B ) and the discharging of used inner gas ( 12B ) takes place downstream with regard to the conveyor line ( 4 ) , in particular the conveying direction ( 4A) , of the electrical heating device ( 16A, 16B ) or within the electrical heating device ( 16A, 16B ) .37.37 . Method according to claim 35 or 36 , characterised in that the charge of inner gas ( 12A) , in particular fresh inner gas ( 12A) , takes place at or after an inlet sealing device ( 18 ) for transferring the metallic strip (2 ) into the heating zone ( 8 ) and the discharge of used inner gas ( 12B) takes place at or before an outlet sealing device (20) for transferring the metallic strip (2 ) out of the heating zone ( 8 ) .

38. Method according to one of claims 35 to 37, characterised in that an inner gas atmospheric pressure of the inner gas atmosphere ( 12 ) upstream with regard to the conveyor line (4 ) , in particular the conveying direction (4A) , of the electrical heating device ( 16A, 16B) is set higher than an inner gas atmospheric pressure downstream with regard to the conveyor line (4 ) , in particular the conveying direction (4A) , of the electrical heating device ( 16A, 16B) .

39. Method according to one of claims 35 to 38, characterised in that the metallic strip (2 ) is heated within the inner gas atmosphere to a strip temperature of greater than or equal to 25 °C, preferably greater than or equal to 100 °C and particularly preferably greater than or equal to 700 °C, and / or to a strip temperature of less than or equal to 1250 °C, preferably less than or equal to 1200 °C and particularly preferably less than or equal to 650 °C .

40. Method according to one of claims 35 to 39, characterised in that the dew point of the inner gas atmosphere ( 12 ) is set up to a value of greater than or equal to -50 °C, preferably greater than or equal to -40 °C and particularly preferably greater than or equal to 0 °C, and / or is set up to a value of less than or equal to 20 °C, preferably less than or equal to 15 °C or less than or equal to 10 °C and particularly preferably less than or equal to 5 °C .

41. Method according to claim 40, characterised in that the dew point at the production line ( 6, 6A, 6B) is set in a section of the production line, preferably in the heating zone ( 8 ) , and / or in one of the heating arrangements of the production line and / orin an annealing section and / or in a soaking section and / or in a cooling section and / or in an overaging section and / or in a furnace exit zone, preferably with regard to the conveyor line (4 ) , in particular the conveying direction (4A) , upstream of a zinc pot .

42. Method according to one of claims 35 to 41, characterised in that the gas conditions regarding the inner gas atmosphere ( 12 ) can be changed during operation, in particular regarding to a gas composition, a gas temperature, a dew point, a strip char-acteristics, an operation condition of any former process and / or the like .

43. Method according to one of claims 35 to 42, characterised in that an oxidation layer is reduced by using a reducing atmosphere .

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