FURNACE FOR HEATING METAL GOODS

Abstract

The invention pertains to a furnace for heating metal goods.

Description

FIELD OF THE INVENTION

The invention pertains to a furnace for heating metal goods.

BACKGROUND OF THE INVENTION

Furnaces for heating metal goods are known in the form of reheating furnaces and heat treatment furnaces for semi-finished metal products or for tubes of steel or nonferrous metals. In such furnaces, the corresponding metal goods are heated for a subsequent hot-forming process, a quenching process or for carrying out a thermal process in the furnace.

In this description, the term metal goods consequently refers to semi-finished metal products or metal tubes. Semi-finished metal products may consist of billets, blooms or slabs.

Popular designs of such furnaces for heating metal goods are pusher furnaces and walking beam furnaces.

In pusher furnaces, the metal goods lie on rails within the furnace chamber and are pushed through the furnace by means of a pushing mechanism. In this case, the individual metal goods tightly adjoin one another such that the pushing mechanism advances the entire furnace content when a new metal item is pushed in.

In a walking beam furnace, the transport system for transporting the metal goods through the furnace chamber comprises two types of tubes or beams. The first type of these tubes or beams, which are also referred to as fixed systems (and comprise horizontal and vertical tubes and/or beams), are immovable and serve for supporting the metal goods. The second type of tubes or beams, which are also referred to as lifting systems (and once again comprise horizontal and vertical tubes and/or beams), move up and down between the fixed systems along an approximately circular or rectangular path. The metal goods lying on the fixed systems are lifted, advanced by a certain distance and then once again deposited onto the fixed systems by means of the lifting systems during each of the cyclic motions along the path.

Correspondingly designed furnaces for heating metal goods, particularly pusher furnaces and walking beam furnaces, typically have a furnace chamber with an essentially tunnel-like shape, i.e. with an input side on one end and an output side on the opposite end of the furnace chamber. In order to fire the furnace chamber, roof burners are arranged on the ceiling of the furnace above the transport plane of the metal goods being transported through the furnace chamber (the so-called “upper furnace”) and/or lateral burners are arranged on the sidewalls of the furnace. Lateral burners are also arranged on the sidewalls of the furnace underneath the transport plane of the metal goods being transported through the furnace chamber (the so-called “lower furnace”). Since additional firing of the furnace chamber is typically required in the holding zone of the furnace, i.e. in the region of the furnace chamber situated adjacent to the output side, additional burners in the form of so-called end burners are typically arranged in the upper and/or lower furnace on the end wall of the furnace at the output side.

Furnaces for heating metal goods are usually divided into at least three zones, namely into an input zone (that is also referred to as “convective zone” in the prior art), a heating zone and a holding zone.

The input zone is situated directly adjacent to the furnace inlet and serves for preheating metal goods introduced into the furnace chamber. The input zone is typically not heated by means of burners, but rather the hot flue gases extracted from the holding and heating zones.

The heating zone follows the input zone referred to the transport direction of the metal goods being transported through the furnace chamber. The essential heating or heat treatment of the metal goods takes place in this heating zone of the furnace chamber. For this purpose, the heating zone is fired with lateral burners or roof burners in the upper furnace and with lateral burners in the lower furnace. Since firing of the upper furnace can in the heating zone of the furnace chamber typically be realized in a simpler and more cost-efficient fashion with lateral burners than with roof burners, it is attempted to largely heat by means of lateral burners in the heating zone. However, this is only possible up to a maximum furnace width because a sufficiently uniform temperature distribution over the entire width of the furnace can no longer be achieved with lateral burners if the furnace width exceeds a certain value. Consequently, the upper furnace of the heating zone is fired by means of roof burners if the furnace width exceeds a certain value because a uniform temperature distribution over the entire width of the furnace can be achieved with roof burners. However, a uniform temperature distribution cannot be adjusted in the lower furnace by means of these roof burners.

The holding zone extending up to the furnace outlet follows the heating zone referred to the transport direction of the metal goods being transported through the furnace chamber. In the holding zone, the upper furnace is typically fired by means of roof burners, lateral burners or end burners and the lower furnace is fired by means of lateral burners or end burners.

Correspondingly designed furnaces for heating metal goods basically have stood the test of time. In heating furnaces of the above-described type, however, it would frequently be desirable to achieve a more uniform temperature distribution than that attainable with lateral burners according to the prior art in the lower furnace of the heating zone. This respectively applies, in particular, to furnaces with a significant width and to the heating of metal goods with a great length that need to be heated in correspondingly wide furnaces.

The invention is based on the objective of providing a furnace for heating metal goods that makes it possible to fire the heating zone of the furnace in an improved fashion. It should particularly be possible to realize a more uniform temperature distribution than in furnaces according to the prior art in the lower furnace of the heating zone, particularly in furnaces with a significant width.

SUMMARY OF THE INVENTION

In accordance with the present invention, there is provided a furnace for heating metal goods, said furnace comprising:

a furnace chamber that is designed for accommodating metal goods;

an input side with a furnace inlet, through which the metal goods to be heated in the furnace chamber can be introduced into the furnace chamber;

an output side with a furnace outlet, through which the metal goods heated in the furnace chamber can be removed from the furnace chamber;

a ceiling that defines the top of the furnace chamber between the input side and the output side;

a furnace floor that defines the bottom of the furnace chamber between the input side and the output side;

sidewalls that laterally define the furnace chamber between the input side and the output side;

burners for firing the furnace chamber, wherein the burners comprise at least one of the following types of burners: roof burners arranged in the region of the ceiling or lateral burners arranged in the region of the sidewalls; and

additional burners for firing the furnace chamber that are arranged in the region of the furnace floor.

The basic idea of the invention is comprised of firing the furnace chamber of the furnace by means of additional burners that are arranged in the region of the furnace floor (and referred to as “additional burners” herein). Since the additional burners are arranged in the region of the furnace floor, the lower furnace of the inventive furnace can be fired by means of the additional burners. The lower furnace can be fired over the entire furnace width in the region of the heating zone of the inventive furnace by means of the additional burners provided in accordance with the invention because the arrangement of the additional burners in the region of the heating zone of the lower furnace is—in contrast to the lateral burners used in the prior art for firing the lower furnace in the region of the heating zone—not limited to the sidewalls, but the additional burners rather may be arranged in the region of the furnace floor over the entire furnace width in the heating zone of the furnace. This makes it possible to achieve a much more uniform temperature distribution in the region of the lower furnace of the heating zone than in furnaces according to the prior art, in which the heating zone can only be fired by means of lateral burners.

A furnace according to the present invention (hereinafter referred to as “an invention furnace” or “the inventive furnace”) preferably features an input zone, a heating zone and a holding zone. These zones may be respectively realized in accordance with the prior art and as described above, wherein the lower furnace of an inventive furnace can—in contrast to the prior art—also be fired by means of the additional burners.

The additional burners are preferably arranged in the region of the heating zone of the inventive furnace. According to an embodiment, it is proposed that the additional burners are exclusively arranged in the region of the heating zone of the furnace.

The burners are preferably not oriented upward, i.e. in the direction of the goods to be heated in the furnace, but rather in at least one of the following directions: in the direction of the output side or in the direction of the input side of the furnace. This makes it possible to achieve a particularly uniform temperature distribution. The uniformity of the temperature distribution can be additionally improved in that the additional burners, which are respectively oriented in one direction, extend parallel to one another such that the flames or burner gas jets generated in one direction by the additional burners extend parallel to one another.

Since the additional burners are arranged in the region of the furnace floor, the furnace operation, particularly the flue gas conveyance and the transport of the goods through the furnace, is not negatively affected by the additional burners.

For example, the furnace floor of an inventive furnace does not have to be designed in a special way in order to accommodate the additional burners. For example, the furnace floor of an inventive furnace may essentially be realized in the form of a horizontal plane. This allows a particularly uniform flame orientation and flue gas conveyance in the lower furnace.

The inventive furnace may be realized, in particular, in the form of a pusher furnace or a walking beam furnace. In this respect, the inventive furnace may feature the characteristics of a pusher furnace or a walking beam furnace according to the prior art.

The inventive furnace is designed for heating metal goods, particularly metal goods of great length—for example in the form of semi-finished steel products such as billets, ingots or slabs or in the form of metal tubes.

The inventive furnace and its furnace chamber may basically have any size and dimension. However, an inventive furnace preferably features a very wide furnace chamber because the advantageous effect of the additional burners that allow a particularly uniform temperature distribution in the lower furnace—especially in the region of the lower furnace of the heating zone—manifests itself, in particular, in furnaces of great width.

For example, the width of the furnace chamber of the inventive furnace, i.e. the average clearance between the sidewalls, may amount to more than 15 m.

The furnace chamber of an inventive furnace may have a length, for example, of 13 m or more, wherein the length of the furnace refers to the shortest distance between furnace inlet and furnace outlet in the furnace chamber.

All burners of the inventive furnace may be realized in accordance with the embodiments of burners known from the prior art. For example, the burners may consist of high-velocity burners or impulse burners.

The end burners, roof burners and lateral burners of the inventive furnace may be arranged in accordance with the prior art. In this respect, it would be possible, for example, that the furnace features no burners in the region of its input zone. In the region of the heating zone, the furnace may feature, for example, either roof burners or lateral burners in order to fire the upper furnace; if the inventive furnace has a great width, it would also be possible that it only features roof burners for firing the upper furnace in the region of the heating zone. In order to fire the lower furnace, it is preferred that the furnace exclusively features the additional heaters in the region of the heating zone. In the region of the holding zone, the inventive furnace preferably features roof burners, lateral burners or end burners in order to fire the upper furnace; it is preferred that the furnace exclusively features one of these three types of burners for firing the upper furnace in the region of the holding zone. The furnace may feature lateral burners or end burners in order to fire the lower furnace in the region of the holding zone; if the inventive furnace has a great width, it would be possible to exclusively provide end burners for firing the lower furnace in the region of the holding zone.

The furnace may be realized, in particular, in such a way that the furnace chamber can be heated to temperatures in the range between 500° C. and 1300° C., particularly in the region of the heating zone. If the furnace is used for heating metal tubes or semi-finished products for metal tubes, the furnace chamber may be designed, for example, for being heated to temperatures in the range between 500° C. and 1050° C.; in order to heat other semi-finished metal products, for example, in the form of billets, ingots or slabs, the furnace chamber may be designed, for example, for being heated to temperatures in the range between 950° C. and 1300° C.

As in the prior art, the furnace preferably operates in accordance with the counterflow principle, wherein the metal goods are transported from the furnace inlet in the direction of the furnace outlet and the flue gases generated in the holding zone and the heating zone are conveyed in the opposite moving direction toward the furnace inlet and extracted from the furnace chamber at this location. In the region of the input zone of the furnace, part of the thermal energy contained in the flue gases is transferred to the metal goods being introduced into the furnace and these metal goods are thusly pre-heated.

The inventive furnace may feature a device for transporting or guiding the metal goods through the furnace chamber according to the prior art. Consequently, the furnace may therefore feature a pushing mechanism if the inventive furnace is realized in the form of a pusher furnace or a corresponding lifting device for transporting the metal goods through the furnace chamber if the furnace is realized in the form of a walking beam furnace.

For example, the additional burners of the inventive furnace may be arranged directly in the region of the furnace floor, for example in accordance with roof burners, lateral burners or end burners known from the prior art. In order to purposefully orient the additional burners in the direction of the furnace inlet or furnace outlet, however, the additional burners may be arranged in at least one housing disposed in the region of the furnace floor. In this way, the additional burners can be arranged in this at least one housing in such a way that they are protected from the hot furnace atmosphere by the housing, but still can be purposefully oriented, in particular, in the direction of the furnace inlet or furnace outlet. These housings may be comprised, for example, of a refractory ceramic material such as a high alumina refractory material.

According to an embodiment, one or several additional burners may be respectively arranged in one housing, wherein several of these housings may be arranged, for example, at a distance from one another in the region of the furnace floor. However, it would also be conceivable, for example, that all additional burners are arranged in a single housing.

The additional burners may basically be arranged in any position in the region of the furnace floor. However, it is preferred that the additional burners are arranged in the region of the furnace floor over the entire width thereof, particularly over the entire width of the furnace floor in the region of the heating zone of the furnace.

The additional burners may essentially be arranged, for example, along a section that essentially extends parallel to the furnace outlet in the region of the furnace floor. The additional burners are preferably arranged along such a section in the region of the furnace floor, for example, from one sidewall to the other sidewall, i.e. over the entire width of the furnace floor, such that they are equidistantly spaced apart from one another. For example, if the additional burners are arranged in at least one of the aforementioned housings, the housing or the housings may also extend along such a section, for example, from one sidewall to the other sidewall.

According to the prior art, the metal goods can be transported through the furnace chamber in the region of a plane. This transport plane may be defined by supporting means, on which the goods lie during the transport through the furnace. If the furnace is realized in the form of a pusher furnace, the supporting means may consist, for example, of rails or similar means, on which the goods lie while they are pushed through the furnace chamber by the pushing mechanism. These rails may be water-cooled in accordance with the prior art and protected from the furnace atmosphere by refractory ceramic masses. It would also be possible, for example, to use non-cooled rails of heat-resistant steel.

If the furnace is realized in the form of a walking beam furnace, for example, the transport plane, along which the metal goods are transported through the furnace chamber, may be defined by the plane in which the metal goods are situated when they lie on the fixed systems. The fixed systems and the lifting systems of the walking beam furnace may likewise be realized in accordance with the prior art, i.e. they may once again be comprised of, for example, of water-cooled tubes or rails that may be protected from the furnace atmosphere by a refractory ceramic mass. It would also be possible, for example, to use non-cooled fixed systems and lifting systems of heat-resistant steel.

Accordingly, the inventive furnace may feature, for example, the following additional characteristics:

a plane, along which metal goods to be heated in the furnace chamber can be guided through the furnace chamber, wherein the plane divides the furnace chamber into an upper furnace space (“upper furnace”) that lies between the plane and the ceiling and a lower furnace space (“lower furnace”) that lies between the plane and the furnace floor;

at least one housing, in which the additional burners are arranged;

wherein the clearance between the upper side of the at least one housing and the underside of the plane amounts to at least 40% of the height of the lower furnace space.

Since the clearance between the upper side of the housing or the housings and the underside of the plane amounts to at least 40% of the height of the lower furnace space, the flue gas conveyance and the transport of the metal goods through the furnace chamber are practically not influenced. In this respect, it would also be possible, for example, that the clearance between the upper side of the at least one housing and the underside of the plane amounts to at least 50%, 60%, 70%, 80% or even at least 90% of the height of the lower furnace space.

In technical terminology, the upper furnace space is also referred to as “upper furnace” and the lower furnace space is also referred to as “lower furnace.”

In this description, the height of the lower furnace space or the height of the lower furnace is the average clearance between the transport plane of the semi-finished products and the furnace floor.

The clearance between the upper side of the at least one housing and the underside of the transport plane may amount, for example, to at least 0.5 m, 0.7 m, 0.9 m, 1.0 m, 1.1 m or 1.2 m. The clearance between the upper side of the at least one housing and the underside of the transport plane may furthermore amount to no more than 2.0 m, 1.8 m, 1.6 m, 1.5 m or 1.4 m.

The height of the lower furnace may lie, for example, in the range between 0.8 and 2.7 m.

According to the invention, it was determined that the furnace operation is practically not affected by the housing or the housings if the clearance between the upper side of the at least one housing and the underside of the transport plane is correspondingly chosen. For example, the free cross section of the lower furnace required for enabling the hot flue gases generated in the holding zone and in the heating zone to pass to the input zone is not substantially narrowed.

Another advantage of a correspondingly large clearance between the at least one housing and the transport plane can be seen in that any slag accumulating on the housings cannot come in contact with the metal goods being transported through the furnace chamber or the lifting systems.

According to an embodiment, it is proposed that the furnace features a service channel that is arranged completely or essentially underneath the furnace floor and serves for operating the additional burners. The service channel may be realized, in particular, in the form of a walk-in channel for the personnel. For example, it would be conceivable that the additional burners or the housing or the housings, in which the additional burners are arranged, can be accessed from the ceiling of the service channel in order to operate or service the burners.

According to an embodiment, it is proposed that the inventive furnace features flue gas supply means for supplying the additional burners with flue gases, i.e. combustion gases of the burners of the furnace.

Such flue gas supply means have the particular advantage that the flue gases supplied to the additional burners with the aid of the flue gas supply means can be subjected to afterburning by the additional burners such that a reduction of nitrogen oxides can be achieved in the flue gas.

If the additional burners are arranged in at least one housing as disclosed herein, the flue gas supply means may simply be comprised, for example, of an inlet or of an opening, via which the flue gases can be supplied to the additional burners through the housing or the housings. For example, the flue gas supply means may comprise flue gas lines, by means of which flue gas can be supplied to the additional burners. If the additional burners are arranged in at least one housing, it would be conceivable that such flue gas supply means in the form of the aforementioned openings or flue gas inlets of the aforementioned flue gas lines are arranged on the side of the housing that faces away from the burner outlet of the additional burners. In this way, flue gas can be extracted from the furnace chamber in the region between the additional burners and the furnace inlet with the aid of the flue gas supply means and supplied to the additional burners such that these flue gases can be subjected to afterburning by the additional burners.

According to an embodiment, the inventive furnace may feature the following additional characteristics:

auxiliary burners for firing the furnace chamber that are arranged in the region of the furnace floor between the additional burners and the input side.

These auxiliary burners (in the following referred to as “auxiliary burners”) may be arranged, in particular, in such a way that the heating zone of the furnace can also be fired with these burners.

Such an embodiment is particularly advantageous for furnaces with such a great width, for example, that the furnace chamber also cannot be fired in such a way that the heating zone has the desired temperature or the desired uniform temperature distribution, particularly in the lower furnace, by means of the inventive additional burners.

In other respects, the auxiliary burners may be realized in accordance with the additional burners, i.e. they may be arranged, in particular, in at least one housing that may be realized in accordance with the at least one housing of the additional burners. The at least one housing of the auxiliary burners may furthermore have the same clearance from the transport plane as the at least one housing, in which the additional burners are arranged.

Furthermore, the auxiliary burners can be operated from a service channel that may be realized in accordance with the service channel for operating the additional burners.

The auxiliary burners may furthermore feature flue gas supply means that are realized in accordance with the flue gas supply means for supplying flue gases to the additional burners. In contrast to the flue gas supply means for supplying flue gas to the additional burners, the flue gas supply means for supplying flue gas to the auxiliary burners can extract flue gas from the furnace chamber in the region between the auxiliary burners and the additional burners and supply this flue gas to the auxiliary burners.

All characteristics of the inventive furnace disclosed herein may be arbitrarily combined with one another individually or in combination.

An exemplary embodiment of an inventive furnace is described in greater detail below with reference to the figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a highly schematic sectional view of an inventive furnace, and

FIG. 2 shows a perspective view of a detail of the furnace according to FIG. 1 in the region of the additional burners.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The exemplary embodiment shows a furnace in the form of a walking beam furnace that is identified as a whole by the reference symbol 1 in FIG. 1. The furnace 1 features an essentially tunnel-shaped furnace chamber 3 for accommodating metal goods. On one end - namely the right end in FIG. 1—the furnace 1 features an input side 5 with a furnace inlet 7, through which metal goods to be heated in the furnace chamber 3 can be introduced into the furnace chamber 3. On its opposite end—namely the left end in FIG. 1—the furnace 1 features an output side 9 with a furnace outlet 11, through which metal goods heated in the furnace chamber 3 can be removed from the furnace chamber 3. Between the input side 5 and the output side 9, the top of the furnace chamber 3 is defined by a ceiling 13 and its bottom is defined by a furnace floor 15. The furnace chamber 3 is laterally defined between the input side 5 and the output side 9 by two sidewalls that essentially extend parallel to the plane of projection, wherein only the sidewall 16 facing away from the plane of projection, but not the sidewall facing the plane of projection, is illustrated in FIG. 1.

The furnace chamber 3 is divided into three zones, namely into an input zone 3E situated adjacent to the input side 5, a heating zone 3H that follows the input zone referred to the transport direction of the metal goods 25 and a holding zone 3A that follows the heating zone referred to the transport direction of the metal goods 25 and extends up to the output side 9.

The transport system for transporting the metal goods 25 through the furnace chamber 3 comprises a fixed system of vertical beams and horizontal support tubes 23, onto which metal goods 25 to be transported through the furnace chamber 3 can be placed. The transport system furthermore comprises a lifting system 27, by means of which the metal goods 25 can be lifted off the fixed system 23, advanced by a certain distance in the direction of the output side 9 and then once again deposited onto the fixed system 23 in accordance with the prior art.

The fixed system 23 defines a plane E, along which the metal goods 25 can be transported through the furnace chamber 3.

The transport plane E divides the furnace chamber 3 into an upper furnace 3o and a lower furnace 3u.

In order to fire the upper furnace 3o in the region of the heating zone 3H, the furnace 1 features roof burners 19 that are arranged on the ceiling 13 in the region of the heating zone 3H. Alternatively, the furnace 1 could also feature lateral burners 21 for firing the upper furnace 3o in the region of the heating zone 3H, wherein these lateral burners would be arranged in the region of the sidewalls and only the lateral burners 21 thereof arranged in the region of the sidewall 16 shown are indicated with broken lines in FIG. 1. In order to fire the upper furnace 3o in the region of the holding zone 3A, the furnace 1 features end burners 17 that are arranged in the upper region of the output side 9. The furnace 1 features end burners 10 that are arranged in the lower region of the output side 9 in order to fire the lower furnace 3u in the region of the holding zone 3A.

In the region of the heating zone 3H, additional burners 29 are arranged in the region of the furnace floor 15. These additional burners 29 are oriented toward the output side 9 such that parallel flames extending toward the output side 9 can be produced with the burners 29.

The additional burners 29 are arranged along a section that extends parallel to the output side 9 and perpendicular to the plane of projection in the region of the furnace floor 15 such that only one of the additional burners 29 is visible in FIG. 1.

On its side that faces the furnace chamber 3, the furnace floor 15 forms a horizontal plane, the horizontal extent of which is not affected by the additional burners 29.

The additional burners 29 are arranged in a housing 30 of a high alumina refractory material and thereby effectively protected from the hot furnace atmosphere.

The housing 30 is provided with flue gas supply means 31 in the form of openings that are arranged on the side of the housing 30 facing away from the burner outlet of the burners 29. In this way, flue gas can be extracted from the region of the lower furnace space 3u between the additional burners 29 and the input side 5 of the furnace 3 through the openings 31 and supplied to the additional burners 29 such that this flue gas can be subjected to afterburning by the additional burners 29.

The height H of the lower furnace space 3u, i.e. the clearance between the transport plane E and the furnace floor 15, amounts to approximately 2.5 m.

The clearance A between the upper side of the housing 30 and the transport plane E amounts to approximately 1.3 m and therefore 52% of the height H of the lower furnace space 3u.

Consequently, the remaining clearance A between the underside of the transport plane E and the upper side of the housing 30 is sufficiently high for allowing flue gases to flow from the region of the holding zone 3A and the heating zone 3H in the direction of the input side 5 and therefore through the input zone 3E of the furnace 1 without relevant flow resistance.

The furnace 1 furthermore features a walk-and service channel 33, from which the additional burners 29 can be operated. The service channel 33 is essentially arranged underneath the furnace floor 15 and allows personnel to access the housing 30 from the ceiling of the channel only such that the burners 29 can be operated and serviced from the service channel 33.

FIG. 2 shows a highly schematic perspective view of the furnace 1 according to the exemplary embodiment illustrated in FIG. 1 in the region of the additional burners 29. In this case, the illustration in FIG. 1 is not true-to-scale referred to the illustration in FIG. 1.

The elongated shape of the housing 30 that extends over the furnace floor 15 transverse to the longitudinal direction of the furnace 1 is illustrated particularly well in FIG. 2.

Claims

1. A furnace for heating metal goods, comprising:

a furnace chamber that is designed for accommodating metal goods;

an input side with a furnace inlet, through which metal goods to be heated in the furnace chamber can be introduced into the furnace chamber;

an output side with a furnace outlet, through which metal goods heated in the furnace chamber can be removed from the furnace chamber;

a ceiling that defines the top of the furnace chamber between the input side and the output side;

a furnace floor that defines the bottom of the furnace chamber between the input side and the output side;

sidewalls that laterally define the furnace chamber between the input side and the output side;

burners for firing the furnace chamber, wherein the burners comprise at least one of the following types of burners:

roof burners arranged in the region of the ceiling or lateral burners arranged in the region of the sidewalls;

additional burners for firing the furnace chamber that are arranged in the region of the furnace floor.

2. The furnace according to claim 1, further comprising:

a plane E, along which metal goods to be heated in the furnace chamber can be transported through the furnace chamber, wherein the plane E divides the furnace chamber into an upper furnace space that lies between the plane E and the ceiling and a lower furnace space that lies between the plane E and the furnace floor;

at least one housing, in which the additional burners are arranged;

wherein the clearance between the upper side of the at least one housing and the underside of the plane E amounts to at least 40% of the height H of the lower furnace space.

3. The furnace according to claim 1, further comprising a service channel that is arranged completely or essentially underneath the furnace floor, wherein the additional burners can be operated from said service channel.

4. The furnace according to claim 1, further comprising a flue gas supply means, through which flue gases can be supplied to the additional burners.

5. The furnace according to claim 1, further comprising:

auxiliary burners for firing the furnace chamber that are arranged in the region of the furnace floor; between the additional burners and the input side.

6. The furnace according to claim 2, further comprising:

a plane E, along which metal goods to be heated in the furnace chamber can be transported through the furnace chamber, wherein the plane E divides the furnace chamber into an upper furnace space that lies between the plane E and the ceiling and a lower furnace space that lies between the plane E and the furnace floor;

at least one housing, in which the additional burners are arranged;

wherein the clearance between the upper side of the at least one housing and the underside of the plane E amounts to at least 40% of the height H of the lower furnace space.

7. The furnace according to claim 2, further comprising a flue gas supply means, through which flue gases can be supplied to the additional burners.

8. The furnace according to claim 2, further comprising:

auxiliary burners for firing the furnace chamber that are arranged in the region of the furnace floor; between the additional burners and the input side.

9. The furnace according to claim 3, further comprising a flue gas supply means, through which flue gases can be supplied to the additional burners.

10. The furnace according to claim 3, further comprising:

auxiliary burners for firing the furnace chamber that are arranged in the region of the furnace floor; between the additional burners and the input side.

11. The furnace according to claim 4, further comprising:

auxiliary burners for firing the furnace chamber that are arranged in the region of the furnace floor; between the additional burners and the input side.