WO2012080249A1

WO2012080249A1 - Process and apparatus for the warming of coils

Info

Publication number: WO2012080249A1
Application number: PCT/EP2011/072609
Authority: WO
Inventors: Werner Luz; Josef Köppl
Original assignee: C.O.P.S. International Gmbh
Priority date: 2010-12-15
Filing date: 2011-12-13
Publication date: 2012-06-21
Also published as: DE102010054537B4; DE102010054537A1

Abstract

The invention relates to a process for the warming of coils (C, C'), which is characterized in that an end face of the coil (C, C') is positioned on the flame plate (3*) of at least one annular jet burner (3) in such a way that the coil (C, C') is heated almost exclusively by heat radiation from the flame plate (3*) of the annular jet burner (3). The invention further relates to a furnace plant for heating coils (C, C').

Description

METHOD AND DEVICE FOR WARMING COILS BY HEAT RADIATION

The invention relates to a method for heating coils. Furthermore, the invention relates to a furnace for heating coils.

Methods and devices for heating coils

(Steel strip rolls) are known in the art

multiple execution known. In processes for heating coils in respective furnace chambers, there is the problem that the coils are partly directly exposed to the flue gas of the burners disposed in the furnace chamber, i.

be heated convectively. This happens locally

Overheating of the sensitive band material with

Temperature peaks between 400 and 600 ° C, resulting in an unacceptable for the subsequent rolling process

Randwelligkeit precipitates. Furthermore, the high flue gas temperatures require the use of special

heat-resistant steels for the furnace chamber. In DE-OS 28 44 551 a method and apparatus for annealing coils ("coils") is described, in which the coils transported with vertically aligned central opening on a conveyor through a tunnel furnace and thereby arranged on both sides next to the coils heating elements .

in the form of burners, for example. In order to avoid damage to the burner facing surface of the outer windings of the coils, it is provided that the coils are protected by an insulation from excessive heating by the flue gases. This isolation can be in Form of a coil immediately surrounding the cylinder or be arranged as arranged in front of the burners plate-shaped shield. A disadvantage of the oven described above, however, is that the additional means for shielding the coil surface increase the design effort in the construction of the furnace, so that this furnace concept is not optimal in terms of cost.

Proceeding from this, the present invention seeks to provide a method for heating coils, which allows a uniform, gentle heating of the coils and also by low investment and operating costs

distinguishes. The object is achieved by a method according to the preamble of claim 1, characterized in that an end face of the coil is aligned on the flame disk at least one annular beam burner such that the coil almost exclusively on thermal radiation of

Flame disc of the annular jet burner is heated.

The particular advantage of the method according to the invention consists in a heating of the coils that is particularly gentle on the methods known from the prior art and at the same time achievable with low process outlay. Thus, the fact that the heat transfer from the disc-shaped flame of the annular jet burner to the at least one surface of the coil takes place almost exclusively via thermal radiation, the atmosphere in the

Heat treatment chamber heated only slightly. In practice, temperatures of the gas atmosphere of about 200 ° C are not exceeded during the entire heating process.

LO / LO 100092WO. December 2011 As a result, the construction of the

Heat treatment chamber can be made with mild steel, since due to the relatively low temperature of the chamber atmosphere no particularly heat-resistant steels must be used. This can be a

Furnace plant with lower investment costs realize.

By aligning the circular face of the

cylindrical coils on the flame disk of the

Ring jet burner is achieved an optimal geometric adaptation of the coil to the flame geometry, so that the

Heat energy can be coupled into the coil particularly efficiently via heat radiation. Coils are in front of you

Further processing in the steel industry, in particular for a rolling process to heat to a predetermined temperature, wherein the inventive method is ideally for a fast, uniform and

material-friendly heating is suitable. Advantageously, the diameter of the flame disk is adapted to the diameter of the end face of the cylindrical coil.

The use of an annular jet burner - sometimes the term "flat flame burner" is common - is ideally suited for a radiation-based

Heating of the coil, since its large-scale flame, which clings to the disk surrounding the torch burner, the surface of the coil to be heated uniformly applied to radiant heat without it to a

Rauchgasbeaufschlagung of the coil comes.

In addition to a uniform and gentle heating of the coils, the heating can also be done very quickly, as well

LO / LO 100092WO December 13, 2011 High energy input minimizes the risk of strong local overheating.

Annular jet burners as such are known in the art (e.g., DE 20 2004 015 205 Ul or EP 0 003 900 Bl).

Instead of a single annular jet burner, an arrangement of several, for example four or eight,

Annular jet burner be provided. These are preferably arranged in such a way to each other and are in the way

operated, that their flames slightly overlap each other and thus produce a gap surface as complete as possible, which the front side of the coil with radiant heat

evenly applied. If the annular end face of the coil is acted upon, then the plurality of annular jet burners are preferably arranged on a circular line with a radius which corresponds to the arithmetic mean of the outer and inner radius of the windings of the coil. It is understood that the plurality of annular jet burners can also be arranged in a different manner relative to each other. For example, an annular jet burner can be placed in the middle, while the remaining annular jet burners are arranged symmetrically around the central annular jet burner, for example on a circular line.

According to a further advantageous embodiment of the invention it is provided that the opposing

End faces of the coil on the flame disk respectively

at least one annular jet burner are aligned, so that the two end faces of the coil with each

Radiation heat to be applied. As a result, a symmetrical heating can be achieved in a simple manner,

LO / LO 100092WO December 13, 2011 which results in particular time advantages. 200 ° C, since the injected radiant heat can be dissipated quickly into the interior of the coil.

To further increase the heat input into the coil

uniform, may be provided according to a further advantageous embodiment of the invention that the coil is moved during the heating relative to the flame disk. In particular, it may be relative to the flame disk of the

Ring jet burner can be set in rotation. Preferably, the coil is set in rotation around its longitudinal or symmetry axis, and accordingly a circular end face rotating around its center point is aligned with the flame disk of the annular jet burner.

According to a further particularly advantageous embodiment of the invention, the coil is heated in a first furnace chamber by aligning an end face on the flame disk of at least one annular jet burner and then kept warm in a second furnace chamber acting as holding furnace over a holding time. During the holding time, a uniform distribution of the heat takes place in the coil.

The flue gases of the at least one annular jet burner can be introduced from the first into the second furnace chamber to keep warm in the first furnace chamber erwärtes coil. By using the heat energy contained in the flue gases of the annular jet burner of the

Heating and holding process particularly energy efficient

LO / LO 100092WO December 13, 2011 be designed, which can significantly reduce operating costs.

The present invention also has for its object to provide a furnace for heat treatment of coils with a first furnace chamber, which allows a fast and smooth and gentle heating of the coil, the furnace should be simple in design and should be characterized by low operating costs.

The object is achieved with a furnace according to the preamble of claim 8, characterized in that in the first furnace chamber at least one annular jet burner is arranged such that the coil in the furnace chamber with an end face on the flame disk of at least one annular jet burner is aligned, so that the coil

Almost exclusively by heat radiation is heated.

For the advantages of the furnace installation according to the invention, the advantages mentioned above apply accordingly.

According to a first embodiment of the invention

Furnace this includes in addition to the first furnace chamber, a second furnace chamber for keeping warm in the first furnace chamber coils, wherein the first and the second furnace chamber are connected to each other via a flue gas line, so that the flue gases of the at least one annular jet burner can be introduced into the second furnace chamber. To ensure a simple loading and unloading of the oven chambers is, according to another advantageous

Embodiment of the invention provided that the furnace

LO / LO 100092WO December 13, 2011 has a common charging unit of the first and the second furnace chamber. This can be designed such that the loading of the furnace chambers takes place from below.

In the following the invention with reference to a

Embodiment illustrative drawing explained in more detail. Show it:

Fig. 1 is a furnace chamber for heat treatment of a coil in

Longitudinal section

Fig. 2, the furnace chamber of Fig. 1 in cross section according to

Section line II-II in Fig. 1,

3 shows the furnace chamber of FIG. 1 with a comparison with FIG.

1 smaller coil in longitudinal section,

Fig. 4, the furnace chamber of Fig. 3 in cross section according to

Section line IV-IV in Fig. 3,

Fig. 5 is a furnace chamber for heat treatment of

metallic of coils in a comparison with FIG. 1 modified embodiment in longitudinal section,

FIG. 6 shows the furnace chamber of FIG. 5 with a view to FIG.

1 smaller coil in longitudinal section,

Fig. 7, the furnace chamber of Fig. 5 in cross section according to

Section line VII-VII in Fig. 5 and

8 shows a furnace for the heat treatment of coils with a first and a second furnace chamber.

LO / LO 100092WO December 13, 2011 Fig. 1 shows a furnace chamber 1 as part of a (not shown in Fig. 1 to 7) furnace system for heating steel coils C, C ^x . The furnace chamber 1 is cuboid in the usual way and has an isolated

Steel housing 2, which encloses a likewise cuboid furnace chamber. At the opposite

Longitudinal walls 2a of the furnace housing 2 (see Fig. 2) each have a ring-shaped jet burner 3 is arranged, which of a

Bursting element 3a is surrounded, which in turn consists of a refractory ceramic material. As is known per se from the prior art and shown in the sectional drawing of FIG. 2, the annular jet burner 3 generates a disc-shaped flame 3 *, which adjoins the burner block surrounding the burner outlet opening, by means of a highly compressed air-fuel mixture emerging from the burner tube 3a conforms and emits a very high radiation power into the furnace chamber due to the large flame surface. The flue gases of the annular jet burner 3 are via a trigger 5 on the ceiling of the furnace chamber 1 from the furnace chamber

led out. In the present case, a steel coil C is considered too

heating metallic piece goods placed in the oven room.

This is stored on a correspondingly shaped receiving unit 4, which allows a loading of the furnace chamber 1 from below.

For heating the coil C in the furnace chamber 1 is now the coil C with its front sides on the vertically adjustable receiving unit 4 so relative to the two

Annular jet burners 3 aligned so that the central opening of the coil C is substantially coaxial with the axes of the

Ring jet burner 3 is arranged and the flame disks 3 *

LO / LO 100092WO December 13, 2011 the annular jet 3 the front sides with their

Fully apply radiation energy, as indicated by the arrows in Fig. 2. The diameters of the flame disks 3 * are preferably chosen to be the same or slightly larger than the outer coil diameter. If the diameter of the flame disks 3 * larger than the outer diameter of the coil, it is understood that an exact coaxial

Alignment is not essential. By aligning the end faces of the coil C on the flame disks 3 * of the annular jet burner 3 is achieved that the coil C almost exclusively on the

Heat radiation of the flame disc 3 * of the annular jet burner 3 is heated. This is a particularly gentle and at the same time with little process engineering effort

achievable heating of the coil C, since the radially outflowing flue gases of the flame disk 3 * with the

Coil surface practically does not come into contact.

At the same time the temperature of the furnace atmosphere remains

below a temperature of preferably 150 - 200 ° C, so that the structural components of the furnace chamber 1 made of normal steel, i. made of non-heat-resistant and therefore expensive steels, can be made. The temperature of the

Coil surface also does not exceed a value of about 200 ° C, so that a thermal damage of the

Coil material, which could be reflected, for example, in a wavy strip surface is excluded. The average temperature of the coil C can at corresponding

Process control to a value of about 90 - 110 ° C are set.

LO / LO 100092 O 13th December 2011 3 and 4 show the furnace chamber 1 of Figs. 1 and 2, in which case a coil 0 is heated with a smaller diameter in the furnace chamber 1. This is in turn aligned coaxially with the annular jet burners 3. Due to the smaller diameter of the coil C, the annular jet burners 3 can be operated in such a way that a flame disk 3 * with a smaller diameter is produced, wherein this is preferably in turn adapted to the coil diameter. Figures 5 to 7 show an oven chamber 1 for ^Λ

Heat treatment of metallic of coils C, C ^x in a modified version compared to FIG. 1. In this case, instead of a ring-shaped jet burner arranged in the center of the burner brick 3a, there is a distribution of a total of eight

Annular jet burners 31, 32 provided around the center of the burner block 3a around. More specifically, a first group of four annular jet burners 31 are provided on an outer annulus and a second group of four annular jet burners 32 are provided on an inner concentric annulus. These can be operated in groups, but also together. For this purpose, they are common across groups

Fuel ring pipes 3b and 3c supplied primary air ring wires. In the case of a coil C with a comparatively large diameter, both ring-beam burner groups 31, 32 can be operated synchronously in order to maximize the area of the annular-jet burner groups 31, 32 facing each other

Front side of coil C with radiant energy too

apply. It is understood that the annular jet burners 31, 32 need not be designed as powerful as the centrally located in the burner block 3a annular jet burner 3, since their respective flame disks the coil surface

LO / LO 100092WO. December 2011 combined and preferably with some overlap

apply.

Another special feature of the oven chamber of FIGS. 5 to 7 is that the receiving unit 4 comprises a plurality of - in the present case four - rollers 4a, on which the coil C is mounted. At least one of these rollers 4a can be set in rotation by a drive unit, not shown, wherein the coil C mounted thereon also rotates. This ensures that the individual

Flame disks of the annular beam burners 31, 32 each act not only a surface portion on the front side of the coil C with radiant energy, but the

Distribute radiant energy to the front. This local temperature peaks are avoided and the annular beam burners 31, 32 can be operated with higher power to achieve a total of faster heating of the coils. It is understood that a device for rotating the coil is advantageous even with only one annular jet burner 3 per longitudinal wall of the furnace chamber 1.

Fig. 5 shows the case of a coil 0 ^Λ with respect to the coil C reduced diameter. In this case, only the second group of burners 32 for heating the coil

operated.

Finally, FIG. 8 shows a furnace for heat treatment of coils with a first furnace chamber 10 and a second furnace chamber 20. The first furnace chamber 10 is provided for the rapid heating of coils C, while the second furnace chamber 10 is provided for the rapid heating of coils C.

Furnace chamber 20 acts as a holding zone in which the axial temperature profile of the heated in the furnace chamber 10 coils

LO / LO 100092WO December 13, 2011 C evened. As shown, the first and second furnace chambers 10, 20 are via a flue gas duct 5a

connected to each other, so that the flue gases generated in the furnace chamber 10 by the annular jet burner 3 from the

Furnace chamber 10 can be discharged and can flow into the furnace chamber 20 to provide the desired temperature for the holding phase of the coil C here.

During operation of the kiln plant, in each case a coil C is conveyed into the kiln chamber 10 via a feed unit arranged below the kiln chambers 10, 20 and heated there in the manner described above. In this case, the coil C is preferably set in rotation about its longitudinal axis in order to achieve the most uniform possible heating by absorption of the thermal radiation of the annular jet burner. The heated coil C is then lowered after completion of the heating process and the charging unit acting as the holding zone

Furnace chamber 20 supplied. Here, the coil C is held for a predetermined duration, with the first

Oven chamber 10 outflowing flue gases of the annular jet burner 3 - in the first furnace chamber 10 is already another coil C is heated - provide the necessary temperature for this purpose. During the holding time, the temperature of the front-side coil surface decreases from a maximum value of, for example, about 200 ° C, while seen in the axial direction inner region of the coil C so far heated up over the entire axial length of the coil C, the desired temperature, for example 90 to 110 ° C is set and the coil C thus a suitable temperature for more

Has processing steps.

LO / LO 100092WO. December 2011 It is understood that specified parameter values, such as

For example, temperatures are to be understood as purely exemplary.

LO / LO 100092WO. December 2011

Claims

claims

Method for heating coils (C, C),

d a d u r c h g e k e n e c e, e s one end face of the coil (C, C) on the flame disk of at least one annular jet burner (3) in such a way

is aligned, that the coil (C, C ') is heated almost exclusively by thermal radiation of the flame disc (3 *) of the annular jet burner (3).

Method according to claim 1,

d a d u r c h e k e n c i n e s, the diameter of the flame disk (3 *) on the

Diameter of the front side of the coil (C, C) is adjusted.

Method according to claim 1 or 2,

d a d u r c h g e k e n e z e n e, t a, s the opposite end faces of the coil (C, C) on the flame disk (3 *) are aligned in each case at least one annular jet burner (3).

Method according to one of claims 1 to 3,

d a d u r c h e k e n c e, that is, the coil (C, C) during heating relative to

Flame plate (3 *) is moved.

Method according to claim 4,

characterized in that the coil (C, C) is set in rotation. Method according to one of claims 1 to 5, characterized in that the coil (C, C) in a first furnace chamber (10) by aligning an end face of the coil (C, C) on the flame disk (3 *) of the at least one

Annular jet burner (3) is heated and then kept warm in a holding furnace (10) acting as the second furnace chamber (20) over a holding time.

Method according to claim 6,

The flue gases of the at least one annular jet burner (3) from the first furnace chamber (10) are introduced into the second furnace chamber (20) for keeping the coil (C, C) heated in the first furnace chamber (10).

Furnace for heat treating coils (C, C) with a first furnace chamber (10),

In the first furnace chamber, at least one of the first furnace chambers is at least one of them

Annular jet burner (3) is arranged such that the coil (C, C ') in the first furnace chamber (10) with an end face on the flame disk (3 *) of the at least one annular jet burner (3) is alignable, so that the coil (C , C) can be heated almost exclusively by heat radiation.

Furnace plant according to claim 8,

characterized in that the furnace installation comprises, in addition to the first furnace chamber (10), a second furnace chamber (20) for keeping warm the coil (C, C) heated in the first furnace chamber (10), wherein the first and the second furnace chamber (10, 20) are connected to one another via a flue gas line, so that the flue gases of the at least one annular jet burner (3) can be introduced into the second furnace chamber (20).

10. Furnace installation according to claim 9,

There is provided a common feed unit of the first and second oven compartments.

11. Furnace installation according to claim 10,

The feed system is designed in such a way that the loading of the oven chambers (10, 20) takes place from below.