EP1532281B1 - Cooling plate for metallurgic furnaces - Google Patents

Abstract

The invention relates to a cooling plate (1,16) made of copper or a low-alloy copper alloy for metallurgic furnaces provided with high-strength sheet steel (2) on the outside of the furnace . Said cooling plate has at least one, preferably at least two, coolant channels which extend inside the cooling plate (1,16), whereby coolant tube pieces used for feeding the coolant and discharging said coolant extend through the high-strength sheet steel (2) of the furnace and are guided in an outer direction. Retaining tubes are arranged on the cooling plate (1,16) and are provided with retaining disks which are arranged outside the high-strength sheet steel (2) of the furnace and which fix the cooling plate (1,16) in the direction of the inside of the furnace. The retaining tubes and retaining disks are preferably made of steel.

Description

The invention relates to a cooling plate, consisting of copper or low-alloy copper alloy, provided with an outer furnace armor plate metallurgical furnaces with at least one, preferably at least two, extending inside the cooling plate coolant channels, wherein coolant pipe pieces for the Kühlmittelzu- or -ausablauf by the furnace armor plate are led to the outside.

Such cooling plates are arranged between the jacket and the lining and connected to a cooling system. On the side facing the furnace interior, the cooling plates are partly provided with refractory material.

From the DE 39 25 280 a cooling plate is known in which the cooling channels are formed by cast-in cast iron tubes. The carrier is also connected to the cooling system. These plates have a low heat dissipation due to the low heat conductivity of the cast iron and because of the resistance between the cooling tubes and the plate body, caused by an oxide layer or an air gap.

In the event of a loss of the blast furnace masonry after a certain period of operation, the inner surface of the cooling plates is exposed directly to the furnace temperature. Since the furnace temperature is far above the melting temperature of the cast iron and the internal heat transfer resistance of the cooling plates lead to insufficient cooling of the hot plate side, accelerated wear of the cast iron plates is unavoidable and the life is limited accordingly.

In the DE 199 43 287 A1 discloses a copper cooling plate, which is connected near the upper coolant pipe pieces by means of a fixed-point fastener fixed to the furnace shell. In addition, the upper coolant pipe pieces are also fixedly connected to the furnace shell. Other fasteners are designed as loose-point fasteners that allow for movement in both the horizontal (x) and vertical (y) directions. The lower coolant pipe pieces are gas-tight connected only by means of conventional compensators with the furnace shell. In this area, the cooling plate is therefore fixed in any of the three spatial directions.

Due to the fact that the furnace interior facing side of the cooling plate reaches temperatures of more than 300 ° C and facing the furnace shell Side on coolant temperature, ie ambient temperature remains, the cooling plate is exposed to very large thermally induced stress forces. At the cooling plate of DE 199 43 287 A1 This leads to the fact that the plate, which is indeed completely fixed in several places, plastically deformed under the influence of temperature and bulges like a bowl in the interior of the oven during cooling. Cracks in the coolant pipe sections and coolant outlet is therefore the result.

Compared to the prior art, the object of the invention is to provide a cooling plate in which such a bowl-like deformation is no longer possible and in which therefore no voltage-related cracks in the coolant pipe pieces occur more.

This object is achieved according to claim 1. The cooling plate is provided with holding tubes, which are guided through the furnace armor plate to the outside and which are provided after passing through the furnace armor plate with fasteners, in particular holding plates or retaining washers, and wherein the holding tubes and the fasteners are made of a steel, which is opposite to copper or low-alloyed copper alloy has increased strength.

The cooling plate according to the invention is movable in the positions of the holding tubes both in the vertical (y) and horizontal (x) direction, while a movement in the z-direction, ie a "Verschüsselung" in the direction of the furnace interior, of the attached to the holding tubes fasteners, which are supported outside of the furnace shell against this is prevented.

Any nonetheless occurring stresses in the z-direction are not carried - as in the prior art - by the copper coolant tube pieces which are not suitable for this purpose, but by the holding tubes and fastening elements made of a much better suitable material.

The material which is specific for the holding tubes and fastening elements is steel, if appropriate also stainless steel, insofar as it fulfills the requirement of a substantially increased strength in comparison with copper or low-alloy copper alloy. Furthermore, steel is at least weldable with itself and also weldable with copper or low alloy copper alloy.

The cooling plate according to the invention is connected in a central region by a fixed point fastening element with the furnace armor plate.

Such a fixed-point fastening element may for example be a fastening bolt and fixed at this point the plate in each of the three spatial directions.

The cooling plate according to the invention is thereby fixed in position and can not be moved by thermally induced tension forces from this position. A thermal expansion of the plate, however, is still unlimited possible from this central fixed point.

According to a further advantageous embodiment, the cooling plate - in particular at a height / width ratio of the cooling plate of ≥ 3 - provided with at least one above and / or below the fixed point fastening element arranged loose-point fastener, which allows only mobility in the vertical direction.

Alternatively, the cooling plate is - in particular at a height / width ratio of the cooling plate of <3, preferably <2 - with at least one left and / or right of the fixed point fastener arranged Lospunkt fastener, which only allows mobility in the horizontal direction, Mistake.

Such a loose-point fastener may, for example, a fastening bolt with disc, the disc remains unglued with the furnace armor plate and can slide in a direction in one direction, be fixed and - depending on the orientation of the fastener - the plate either in x or in y Direction, at least in the z-direction.

Both mentioned variants, in addition to the fixation achieved by the central fixed point, ensure that the cooling plate is now not merely fixed in its entirety in its position, but rather that the cooling plate is also secured against rotation caused by thermally induced tensioning forces. Furthermore, one is Thermal expansion of the plate in the allowed by the Lospunkt fasteners directions freely possible.

A particularly preferred embodiment of the cooling plate according to the invention is that it has webs and grooves on the side facing the interior of the furnace, wherein the webs are segmented in their longitudinal direction.

The webs are that part of the cooling plate that is the least exposed to the cooling effect of the coolant. The webs therefore reach the maximum temperature of the entire cooling plate (the above-mentioned about 300 ° C). By dividing the webs into individual sections, the tension forces caused by the thermal expansion of the webs are reduced to the minimum possible. The subdivision of the webs would also be taken alone in known from the prior art cooling plates a suitable means to reduce the "Encryption" of the cooling plates and to increase the life of the cooling plates, in particular the coolant pipe sections significantly.

In order not to impair the mechanical strength of the entire cooling plate, it is preferred that the segmentation of the webs is designed as arranged substantially perpendicular to the webs cuts.

Preferably, these cuts are further designed such that they are not arranged above, but between the coolant channels. In the event of cracking, this can reduce the risk of further tearing into the coolant channels.

In order not to impair the carrying capacity of the - usually horizontally extending - webs, it is preferred that the segmentation of the webs is designed so that the individual segments offset in the horizontal direction against each other.

Various other embodiments relate to the detailed design of holding tube, fastener and coolant pipe piece. These particular embodiments are subject matter of claims 9 to 16.

In principle, it is preferred that a holding tube surrounds a respective coolant pipe piece, that is to say that a holding tube is led outwards through the furnace shell and a coolant pipe piece is guided through the furnace shell to the outside in each case inside a holding tube.

The type of connection between the holding tube and the cooling plate or between the coolant tube piece and the cooling plate or even between the holding tube and the coolant tube piece can be varied.

According to a first and preferred variant, a disc-shaped connecting piece is welded to the holding tube surrounding the coolant tube piece and this connecting piece is screwed onto the cooling plate. The coolant pipe piece is welded to the cooling plate.

According to a second variant, the holding tube surrounding the coolant tube piece is welded directly to the cooling plate, and the coolant tube piece is also welded to the cooling plate.

According to a further variant, a disc-shaped or annular connecting piece is inserted between the coolant pipe piece and the retaining pipe. Coolant pipe section and retaining pipe sit on this connector. Connection between the connecting piece and the cooling plate on the one hand, and between the connecting piece and the coolant pipe piece or holding tube is preferably carried out by welding.

According to another variant, the coolant pipe piece is made in one piece and provided with a flange, which flange is fixed to the cooling plate. The holding tube surrounds the coolant pipe piece, sits on this flange and is secured thereto by welding.

According to a further variant, a holding tube is also designed as a coolant tube piece, wherein both functionalities, i. the coolant supply and discharge and the holding function are carried by this one piece of pipe.

With the exception of the last-mentioned variant, in all embodiments the coolant tube pieces can be made either from the same base material as the cooling plate or another, preferably the material of the holding tube.

For the latter variant, this choice does not exist, here is the coolant tube at the same time holding tube and therefore made in any case of the material of the holding tube.

• Fig. 1: Zwei-Kanal Kühlplatte
• Fig. 2: Vier-Kanal Kühlplatte
• Fig. 3: Anordnung mehrerer Kühlplatten
• Fig. 4: Segmentierung einer Vier-Kanal Kühlplatte
• Fig. 5-9: verschiedene Halterohrausführungen

The invention will be described below in the drawings Fig. 1 to Fig. 9 explained in more detail.

• Fig. 1 : Two-channel cooling plate
• Fig. 2 : Four-channel cooling plate
• Fig. 3 : Arrangement of several cooling plates
• Fig. 4 : Segmentation of a four-channel cooling plate
• Fig. 5-9 : different holder tube designs

Fig. 1 : Shows a two-channel cooling plate 1, which is attached to a furnace steel jacket. 2 The cooling plate is made of copper and has webs 3 on the side facing the furnace interior. The gap between the cooling plate 1 and furnace armor plate 2 is backfilled with refractory material. Above and below and - not shown - the side of the cooling plate 1 more cooling plates 1 ' are arranged. The cooling plate 1 is provided with vertically extending cooling channels 5 , which are designed as blind holes of the cast or rolled plate body. At the upper and lower ends of each cooling channel 5 are coolant pipe pieces 6 for the supply and discharge of coolant (usually water) passed through the furnace shell 2 . At each coolant pipe piece 6 - this surrounding - a holding tube 7 is also guided outwardly through the furnace shell. The holding tube 7 is welded to a disc-shaped connecting piece 8 , which in turn is fastened by screw 9 to the cooling plate 1 . Outside the furnace shell 2 , the holding tube 7 is provided with a welded-on retaining disk 10 , which limits the mobility of the cooling plate 1 in the direction of the furnace interior. Holding tube 7 and coolant pipe piece 6 are gas-tightly connected to the furnace armor plate 2 by means of a conventional compensator 11 . In the middle of the cooling plate 1 , this is fixedly connected to the furnace armor plate 2 by means of a fix point fastening 12 designed as a fastening bolt. The fixed point attachment 12 is gas-tight welded to the furnace armor plate 2 . Above and below the fixed point attachment 12 Lospunkt fasteners 13 are arranged. The Lospunkt fasteners 13 are also designed as fastening bolts, but these are not gas-tight welded to the furnace armor sheet 2 , but can slide in a guide 14 up and down. To seal against the interior of the oven sealing caps 15 are mounted on the Lospunkt fasteners 13 .

Fig. 2 shows a four-channel cooling plate 16, which up to twice the number of cooling channels 5 with the in Fig. 1 shown cooling plate 1 is substantially identical. Due to the differently designed height / width ratio, the Lospunkt-fasteners 13 are not above and below the fixed-point attachment 12th attached, but each side of it. The guides 14 of the Lospunkt-mounts 13 are arranged so that a sliding in the horizontal direction is possible.

Fig. 3 schematically shows the arrangement of two-channel cooling plates 1 and four-channel cooling plates 16 in an oven. Also shown is the coordinate system illustrating the x, y, and z directions, which have been repeatedly referred to in the text.

Fig. 4 shows the segmented in the horizontal direction webs 3 of the cooling plate 16. The individual segments are each about the same size and offset in the horizontal direction about half their length against each other.

Fig. 5 shows an enlarged view of the preferred variant of the inventive embodiment of holding tube 7, coolant pipe piece 6 and the attachment of the connecting piece 8 by means of screw 9 to the cooling plate . 1

In the Fig. 6 The design shown differs from that in Fig. 5 shown in that the connection of holding tube 7 and cooling plate 1 is made by welding.

Fig. 7 shows an embodiment in which on the connecting piece 8, both the holding tube 7, and the coolant pipe piece 6 are fixed.

Fig. 8 illustrates an integrally executed, provided with a flange coolant pipe piece 6, wherein the retaining tube 6 is attached to this flange.

Fig. 9 shows a special form. On a welded to the cooling plate 1 annular connector 8 sets a welded to this piece of pipe 17 , the blank 17 is made of the material of the holding tubes, so for example steel, and due to - compared with copper - higher strength at the same time as a coolant pipe section and as Holding tube is used.

In all drawings Fig. 5 to 9 fix directly outside the furnace shell 2 attached, welded to the holding tubes 7,17 retaining washers 10, the respective cooling plate 1 in the z-direction to the furnace interior.

Claims (16)

1. Cooling plate (1, 16), consisting of copper or low-alloy copper alloy, for metallurgical furnaces provided with an outer furnace casing plate (2), having at least one coolant passage (5) which runs inside the cooling plate (1, 16), coolant pipe sections (6) for coolant to flow in and out being led to the outside through the furnace casing plate (2), characterized in that the cooling plate (1, 16) is provided with holding pipes (7) which are led to the outside through the furnace casing plate (2) and which, after they have been passed through the furnace casing plate (2), are provided with securing elements (10), in particular holding plates or holding disks, the securing elements being supported against the outside of the furnace casing, and the holding pipes (7) and the securing elements (10) being made from a steel which has an increased strength compared to copper or low-alloy copper alloy, and in that the cooling plate (1, 16) is connected to the furnace casing plate (2) in a central region by means of a fixed-point securing element (12).
2. Cooling plate (1, 16) according to Claim 1, characterized in that there are at least two coolant passages (5) which run inside the cooling plate (1, 16).
3. Cooling plate (1, 16) according to Claim 1 or 2, characterized in that it is provided with at least one movable-point securing element (13) which is arranged above and/or below the fixed-point securing element (12) and allows mobility only in the vertical direction.
4. Cooling plate (1, 16) according to Claim 3, characterized in that the cooling plate (1, 16) height/weight ratio is ≥ 3.
5. Cooling plate (1, 16) according to Claim 1 or 2, characterized in that is provided with at least one moveable-point securing element (13) which is arranged to the left and/or to the right of the fixed-point securing element (12) and allows mobility only in the horizontal direction.
6. Cooling plate (1, 16) according to Claim 5, characterized in that the cooling plate (1, 16) height/width ratio is < 3.
7. Cooling plate (1, 16) according to Claim 6, characterized in that the cooling plate (1, 16) height/width ratio is < 2.
8. Cooling plate (1, 16) according to one of Claims 1 to 7, characterized in that it has tongues (3) and grooves on the side which faces the interior of the furnace, the tongues (3) being segmented in their longitudinal direction.
9. Cooling plate (1, 16) according to one of Claims 1 to 8, characterized in that a holding pipe (7) - in each case surrounding a coolant pipe section (6) - is secured, for example screwed or welded, to the cooling plate (1, 16).
10. Cooling plate (1, 16) according to one of Claims 1 to 9, characterized in that a connecting piece (8) is provided between holding pipe (7) and coolant pipe section (6).
11. Cooling plate (1, 16) according to Claim 10, characterized in that the connecting piece is formed in the shape of a ring or a disk.
12. Cooling plate (1, 16) according to one of Claims 1 to 8, characterized in that a coolant pipe section (6) is formed as a single part and is provided with a flange which is secured to the cooling plate (1, 16).
13. Cooling plate (1, 16) according to Claim 12, characterized in that a holding pipe (7) - surrounding the coolant pipe section (6) - is secured to the flange.
14. Cooling plate (1, 16) according to Claims 1 to 13, characterized in that the pipe sections (6) for coolant to flow in and out are made from the same material as the cooling plate (1, 16).
15. Cooling plate (1, 16) according to Claims 1 to 8, characterized in that a pipe section (17) is designed both as a holding pipe (7) and as a coolant pipe section (6).
16. Cooling plate (1, 16) according to one of Claims 1 to 13, characterized in that the pipe sections (7, 17) for coolant to flow in and out are made from the same material as the holding pipes (7).

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