EP0403466B1 - A flushing arrangement for a metallurgical vessel - Google Patents

Abstract

The known pipes arranged in the inner lining of the metallurgical vessel and serving as a flushing device are pressed flat to avoid penetration of melt, whereby the pipe is stressed and can tear off or burst inside the inner lining. Moreover, the gas stream fed is fanned out widely. <??>To avoid such stresses and to obtain a sharply bundled gas jet, at least one rod-shaped insert (26), which extends in the longitudinal direction of the pipe (18) and which forms an annular gap (30) with the inner wall (29) of the pipe, is provided centrally in each pipe (18). <??>The flushing element is suitable for all metallurgical vessels, in particular for steel works converters. <IMAGE>

Description

The invention relates to a flushing device for a metallurgical vessel, in particular for a steelworks converter, with a refractory lining that forms a wear lining and with pipes through which flushing gas flows at predetermined locations of the refractory lining, with at least one rod extending centrally in the longitudinal direction of the pipe in each pipe shaped insert is provided which forms an annular gap with the inner tube wall.

By blowing purging gas into a molten metal, for example through the bottom of a metallurgical vessel, a stirring effect can be achieved in the molten metal, which compensates for imbalances in composition and temperature, causes the deposition of non-metallic inclusions and promotes a certain degassing of the molten metal.

A large number of devices are known for introducing purge gas. For example, the Radex-Rundschau, Issue 3, 1981, pages 499 to 517; EP-A-0 053 554 and EP-A-0 032 350 gas-permeable, refractory converter purging stones as known, such a gas purging plug being used instead of a stone of the refractory lining of the converter. The flushing stone, which has a sheet metal jacket enclosing a porous refractory mass in order to avoid gas escaping from the side, wherein the porous mass can be provided with a directed porosity, thus replaces a conventional stone of the wear lining of the converter. The sheet metal jacket is open to the converter interior; at the opposite end of the sink, at which the sheet metal jacket is closed, a feed line is connected to the sheet metal jacket in a gas-tight manner.

Flushing stones of this type have the disadvantage that they are complicated to manufacture and install, and that an uncontrolled gas passage can occur between the sheet metal casing and the porous, refractory mass contained therein if the refractory mass does not lie completely against the sheet metal jacket. Furthermore, one such Flushing stone leads to wear that is premature compared to the wear lining of the converter, so that material and time-consuming repair measures are required between two readjustments of the wear lining.

Furthermore, it is known (AT-B-265 341) to embed a nozzle tube in a refractory sink, but this has the disadvantage that the sink, which is also used instead of a conventional refractory lining for the converter, always with a certain The minimum amount of purging gas must be applied as long as the purging plug is covered by the melt in order to avoid clogging of the nozzle tube due to the penetration of the melt.

It is also known (EP-A-0 043 338, EP-A-0 021 861 and EP-A-0 043 787) to form a sink from several refractory individual parts with little or no porosity, the individual parts being separated by one Sheet metal jacket to a so-called sandwich sink, which is also installed in place of a conventional stone of the refractory lining of the converter, are held together. In the abutting surfaces of the refractory individual parts, longitudinal grooves or profiled metal inserts, through which cavities that conduct the purge gas are formed, are provided. Apart from the fact that such a sandwich sink must also be produced in a very complicated and expensive manner, it has the disadvantage that a change in the gas permeability can take place during the period of use if an individual part detaches from the adjacent individual part or from the sheet metal jacket. Furthermore, leading wear cannot be ruled out, since the refractory individual parts have a different composition than the refractory stones of the wear lining.

To avoid these disadvantages, it is known (EP-A-0 155 255) to install a metallic flushing plate at predetermined locations on the floor between adjacent refractory bricks, which extends between the flushing bricks from transverse joint to transverse joint. A relatively large amount of stone wear can occur at the joints on the flushing plate. Due to a stone expansion when the metallurgical vessel can be squeezed and thus reduce the amount of purge gas.

EP-B-0 064 449 discloses a flushing device in which a plurality of flat-pressed tubes extending from a distributor located outside the vessel are passed through the converter jacket and the permanent lining and are inserted into recesses which are cut into adjacent stones of the wear lining . The flat-pressed tubes ensure that no melt enters the openings of the tubes, solidifies in them and clogs them so that blowing out is no longer possible. However, the flat-pressed pipes have the disadvantage that due to the small wall thickness and the large width, there is a strong deformation (bulging, undulation) of the pipe. The pipe is then clamped to the wall, the mobility is restricted and the pipe is then torn off during a relative movement between the permanent and wear lining or bursts within the wall. This fact is further promoted by the fact that the thin-walled tube loses toughness during carburization during operation. This results in a relatively large stone wear at the joint points having the flat-pressed pipes, whereby the service life of the wear lining suffers in the area of a defective pipe, so that a premature re-bricking of the vessel is necessary.

Another disadvantage of the flat-pressed tubes is the fact that the gas supplied enters the interior of the vessel relatively broadly, as a result of which the purging effect is adversely affected.

From US-A-4 462 824 a flushing device of the type described in the opening paragraph is known, in which the annular gap is formed by an outer tube and a fixed inner core. The inner solid core is formed by a tube of larger diameter, which is filled with refractory material.

In a flushing device for a metallurgical vessel known from US-A-4,449,701, there is also an outer tube leading through the fire-resistant lining of the vessel and an insert inserted into this outer tube to form an annular gap, which in turn is rod-shaped and consists of a tube filled with refractory material. This tube is supported several times against radial movement in the outer tube and is connected at one end to a plate which, in turn, is welded to the outer tube, concluding the outer tube at the outer end. Similarly, in flushing devices, which are described in DE-OS 23 42 067, supports are provided between the outer tube and the insert located therein, which prevent the insert from moving radially relative to the outer tube.

The invention aims to avoid the disadvantages and difficulties that exist in the known flushing devices, and has as its object to create a flushing device of the type described in the introduction, in which the gas jet enters the inside of the vessel as sharply as possible, but nevertheless penetrates the melt the pipes are prevented even at low gas pressure, and in which the lowest possible different operating conditions, in particular with regard to shape, axial mobility and outlet cross section, occur between the refractory lining and the pipes.

To achieve this object, the present invention provides a flushing device of the type mentioned at the outset, which is characterized in that the insert is formed by a wire and is loose in the part of the tube lying in the wear lining, i.e. is provided without lateral support and is only fixed in position in the axial direction with respect to the tube and that the fixation of the insert has little play in the axial direction with respect to the tube. As a result, the insert can move slightly in the axial direction with respect to the pipe, which prevents the pipe from clogging even under extreme operating conditions (e.g. very small amount of purge gas). Characterized in that the insert in the part of the tube lying in the wear lining is loose, i.e. provided without lateral support and is only fixed in position in the axial direction with respect to the tube, the insert is automatically centered in the tube when the gas is passed through the tube, so that there is always an annular gap between the inner tube wall and the insert during gas flushing.

After a further training of the flushing device according to the invention It is provided that the insert is formed by a wire rope and is loose in the part of the tube lying in the wear lining, that is to say is provided without lateral support and is only fixed in position axially with respect to the tube and that the fixation of the insert here is slight compared to the tube Has play in the axial direction.

Another embodiment of the flushing device according to the invention is characterized in that the insert designed as an inner tube is loose in the part of the tube lying in the wear lining, i.e. is provided without lateral support and is only fixed in position in the axial direction with respect to the tube and that the fixation of the insert has little play in the axial direction with respect to the tube.

It is known from EP-B-0 064 449 to use one or more wires in the longitudinal direction of the tubes in flat-pressed tubes which protrude through the wear lining, which wires have a diameter which corresponds to the thickness of the inner cross section of the tubes, the wire or the wires have the task of preventing further squeezing of the pressed tubes. The wire thus forms a subdivision of the inner tube cross section into two or more interior spaces.

According to the invention, the part of the tube lying in the wear lining and the insert used therein or the inserts used therein are radially symmetrical, which results in thermal expansions distributed uniformly over the cross section, so that the stress on the wear lining caused thereby is evenly distributed over the circumference of the tube .

An embodiment that is easy to manufacture is characterized in that the tube has a circular cross section.

A particularly good fit in recesses cut into stones of the wear lining for receiving the tubes is obtained if the tube has a cross section formed by a regular polygon, preferably a square or hexagonal cross section.

The annular gap preferably has a width of between 1 and 3 mm, the inside diameter of the tube expediently between 4 and 12 mm, preferably between 4 and 8 mm, and the The diameter of the insert is between 2 and 8 mm, preferably between 2 and 5 mm.

Since pipes made of steel tend to become embrittled due to carburizing, adequate strength of the pipe is expediently ensured in that the pipe has a wall thickness which corresponds to approximately half the inside diameter of the pipe.

The ratio of the length of the pipe lying in the wear lining to the inside diameter of the pipe lying in the wear lining is advantageously at least 16, this ratio not only being present in the case of newly bricked converters, but also at the end of a converter journey, i.e. when the converter has to be bricked up again .

Gas supply pipe are connected by lines, the use of each tube being fixed to the gas supply pipe.

A further preferred embodiment, the production of which is also particularly simple, is characterized in that two tubes, which are arranged at a distance from one another in the wear lining of the metallurgical vessel, are connected by line with their ends lying outside the wear lining to a common gas supply tube, and in that the two Pipes have a common insert, which extends from the mouth of one pipe to the mouth of the other pipe.

In order to ensure the best possible centering of the insert in relation to the tube in the radial direction, the insert is expediently fixed in the axial direction on the part of the tube lying outside the wear lining.

Here, the insert can be expediently fixed to the tube by means of a support rib.

With large pipe diameters, the pipe advantageously has a plurality of inserts.

In order to ensure a certain mobility of the insert with respect to the tube, the tube advantageously has a straight tube part which extends at an angle to the part of the tube lying in the wear lining and through which the insert extends.

Expediently, free spaces remaining between the tube and a wear lining made of refractory stones are filled with refractory mass.

The invention is explained in more detail below with reference to the drawing using several exemplary embodiments, with FIG. 1 a longitudinal section through a steelworks converter, FIG. 2 a top view of the bottom of the steelworks converter and FIG. 3 a section along the line III-III of FIG. 2 according to a first embodiment. FIG. 4 shows an enlarged detail of FIG. 2. Fig. 5 shows a flushing device in side view, partly in section. FIG. 6 illustrates the flushing device shown in FIG. 5 in a plan view, likewise in section. FIG. 7 shows a further embodiment of the flushing device in a representation analogous to FIG. 5. 8 and 9 illustrate a further embodiment of the flushing device in axial section and in cross section according to line IX-IX of FIG. 8. Different cross-sectional shapes of tubes and inserts are shown in FIGS. 10 to 13.

The steelwork converter shown in FIG. 1 has a metal outer jacket 1, which is provided with a permanent lining 4 on the inside both on the bottom 2 and on the side walls 3. On the permanent lining, which is formed from refractory bricks 5, a wear lining 7, also made from refractory bricks 6, is bricked up. As can be seen from FIG. 2, the refractory bricks 6 of the wear lining 7 are arranged in rows 10 starting from the center 8 of the bottom 2 or the longitudinal axis 9 of the converter, rows 10 parallel to one another with longitudinal joints 11 and the bricks 6 being adjacent Rows 10 are arranged offset from one another. The adjacent stones 6 of each row form transverse joints 12 opening into the longitudinal joints 11 between adjacent rows 10 and each abutting a side surface of a stone of an adjacent row 10.

Flushing devices 14 are inserted at predetermined points 13 of the base 2, which are preferably provided at approximately the same distance from the center 8 of the base 2 and also at approximately the same distance from one another. According to the embodiment shown in FIGS. 1 to 4, each purging device 14 is formed by a feed pipe 15 for the purging gas which penetrates the metal outer jacket 1 and projects up to a height just below the wear lining 7.

At the end 16 of the supply pipe 15 which is closed at the end, two pipes 18, hereinafter referred to as distributor pipes, welded into the jacket 17 of the supply pipe are arranged with a circular cross section, which extend from the end 16 of the supply pipe 15 in the direction of the converter interior 19 diverge, etc. in the form of a fork-shaped U-shaped bend part 20. These bend parts 20 of the distributor pipes 18 are located in the permanent lining 4 just below the wear lining 7. The bend parts 20 merge into straight-line pipe parts 21 with a circular cross-section, the distance 22 of which is approximately the thickness 23 of a stone 6 the wear lining 7 corresponds. A 6 'of the stones 6 of the wear chuck 7 has recesses 24 which are formed at the corners and which correspond to the cross section of the tube parts 21 and which accommodate the tube parts 21. The space between the tube parts 21 and the stone 6 'is filled with refractory mass 25.

In the distribution pipes 18 are rod-shaped, etc. Inserts 26 formed by a wire are provided, which extend over the entire length of the distributor pipes 18 and protrude into the feed pipe 15. The ends 27 of the inserts 26 protruding into the feed pipe 15 are bent at right angles and fastened to a plate 28 which closes the feed pipe 15 at the end, for example by welding. As a result, the inserts 26 are fixed in the axial direction with respect to the distributor pipes 18. In the radial direction, the inserts are opposite the distributor pipes 18, etc. whose straight tube parts 21, which pass through the wear lining 7, are freely movable, which mobility results from deformation in the elastic region of the inserts 26. When gas flows, the inserts 26 self-center with respect to the inner wall 29 of the distributor pipes 18, so that an annular gap 30 of uniform width is formed between each insert 26 and the inner wall 29 of the distributor pipe 18. The inside diameter of the distributor pipes is 6 mm, the diameter of the insert is 3 mm.

As can be seen from FIG. 5, the distributor pipes between the feed pipe 15 and their curved part 20 still have a straight piece 31, as a result of which there is a certain radial mobility of the insert 26 with respect to this straight piece 31. This radial mobility results in the straight tube part 21, which extends approximately at right angles to the straight piece 31, a slight axial mobility of the insert 26 relative to the tube part 21, whereby a relocation of the annular gap 30 at the free end of the tube parts 21 reliably is prevented, etc. even if only very small amounts of gas are blown into the converter interior through the distributor pipes 18.

The radially symmetrical design of the annular gap 30 allows the kinetic energy of the gas jet to be introduced into the melt in a highly concentrated manner, as a result of which the gas jet can be influenced only slightly. The growth of the annular gap 30 is also largely prevented by this.

A relative movement between the permanent chuck 4 and the wear chuck 7 can be easily absorbed by the straight-line piece 31 of the distributor pipes 18 branching off from the feed pipe 15, so that the distributor pipes 18 are prevented from tearing off. This straight-line piece 31 is advantageously wrapped with a soft or evaporating material, as a result of which a free space for accommodating the resulting relative movements between permanent 4 and wear lining 7 is formed.

As can be seen from FIGS. 1 and 3, only a small volume part of the permanent feed 4 is penetrated by the flushing device 14, so that only a small amount of ramming mass 25, which replaces a stone 5 of the permanent feed 4 at the point of introduction of the feed pipe 15, is required.

According to the embodiment shown in FIG. 7, the insert 26 is also bent in a U-shape and, in the case of fork-shaped distributor pipes 18, extends from the mouth of one distributor pipe 18 via the junction of the feed pipe 15 to the mouth of the opposite second pipe 18. The insert is thereby 26 fixed so far in the axial direction that it cannot be pushed out of the distributor pipes. There is also a good slight mobility in the axial direction with respect to the straight tube parts 21, which also, as mentioned above, prevents the penetration of melt into the distributor tubes and an overgrowth of the annular gap 30.

According to the embodiment shown in FIGS. 8 and 9, the rinsing element is designed as a single element, ie as a single tube 18 ', which is linear from the outside through the metal outer jacket 1 and entire refractory lining of the steel mill converter is guided. The insert 26 'is fixed with respect to the tube 18' via two radially symmetrical ribs 32, 33. One of the ribs is only fixed to the tube 18 'by welding and serves as a guide for the insert 26'. The second opposite rib 33 is fixed to both the tube 18 'and the insert 26 by welding.

10 to 13 different cross-sectional variants for the rinsing device are illustrated. A square tube cross-sectional shape can prove to be particularly favorable if square recesses are cut in the stones 6 'of the wear lining 7, so that one can get by almost without a refractory mass when fixing the distributor pipe 18 or 18' in the wear lining 7. According to the embodiment shown in FIG. 13, the insert 26 is formed by a multi-strand wire rope 34.

The purging device according to the invention enables purging gas to be supplied in a precisely predetermined amount per unit of time as a result of the safe prevention of an overgrowth of the mouth, as a result of which very precise regulation of the purging gas quantity supplied is possible. A particular advantage of the flushing device according to the invention can be seen in the fact that the control can be simplified insofar as a plurality of flushing devices can be actuated with a control element acting in common and not, and so far, each flushing device can be regulated independently - due to the frequent growth of a conventional flushing device have to be. It is thus possible to connect a plurality of flushing devices outside of the converter to a common feed pipe and to provide a control device thereon.

Claims (17)

1. A flushing arrangement for a metallurgical vessel, in particular, a steelworks converter, comprising a refractory lining constituting a working lining (7) and pipes (18, 18') provided at predetermined points of the refractory lining, through which flush gas flows, at least one rod-shaped insert (26, 26') being provided centrally in each pipe (18, 18') and extending in the longitudinal direction of the pipe (18, 18'), said insert forming an annular gap (30) with the pipe inner wall (29), characterized in that the insert (26, 26') is formed by a wire and is provided in the section of the pipe (18, 18') located within the working lining in a loose manner, i.e., without lateral support, and is fixed in its position relative to the pipe (18, 18') merely in the axial direction, the fixation of the insert (26, 26') providing for a slight play relative to the pipe (18, 18') in the axial direction.
2. A flushing arrangement for a metallurgical vessel, in particular, a steelworks converter, comprising a refractory lining constituting a working lining (7) and pipes (18, 18') provided at predetermined points of the refractory lining, through which flush gas flows, at least one rod-shaped insert (26, 26') being provided centrally in each pipe (18, 18') and extending in the longitudinal direction of the pipe (18, 18'), said insert forming an annular gap (30) with the pipe inner wall (29), characterized in that the insert (26, 26') is formed by a wire rope and is provided in the section of the pipe (18, 18') located within the working lining in a loose manner, i.e., without lateral support, and is fixed in its position relative to the pipe (18, 18') merely in the axial direction, the fixation of the insert (26, 26', 34) providing for a slight play relative to the pipe (18, 18') in the axial direction.
3. A flushing arrangement for a metallurgical vessel, in particular, a steelworks converter, comprising a refractory lining constituting a working lining (7) and pipes (18, 18') provided at predetermined points of the refractory lining, through which flush gas flows, at least one rod-shaped insert (26, 26') designed as an internal pipe being provided centrally in each pipe (18, 18') and extending in the longitudinal direction of the pipe (18, 18'), said insert forming an annular gap (30) with the pipe inner wall (29), characterized in that the insert (26, 26') designed as an internal pipe is provided in the section of the pipe (18, 18') located within the working lining in a loose manner, i.e., without lateral support, and is fixed in its position relative to the pipe (18, 18') merely in the axial direction, the fixation of the insert (26, 26') providing for a slight play relative to the pipe (18, 18') in the axial direction.
4. A flushing arrangement according to any one of claims 1 to 3, characterized in that the section of the pipe (18, 18') located within the working lining (7) and the insert (26, 26', 34), or inserts, inserted therein are designed to be radially symmetrical.
5. A flushing arrangement according to any one of claims 1 to 4, characterized in that the pipe (18, 18') has a circular cross section.
6. A flushing arrangement according to any one of claims 1 to 5, characterized in that the pipe (18, 18') has a cross section formed by a regular polygon, preferably a square or hexagonal cross section.
7. A flushing arrangement according to any one of claims 1 to 6, characterized in that the annular gap (30) has a width ranging between 1 and 3 mm.
8. A flushing arrangement according to any one of claims 1 to 7, characterized in that the internal diameter of the pipe (18, 18') ranges between 4 and 12 mm, preferably between 4 and 8 mm, and the diameter of the insert (26, 26', 34) ranges between 2 and 8 mm, preferably between 2 and 5 mm.
9. A flushing arrangement according to any one of claims 1 to 8, characterized in that the pipe (18, 18') has a wall thickness approximately corresponding to half of the internal diameter of the pipe.
10. A flushing arrangement according to any one of claims 1 to 9, characterized in that the ratio of the length of the pipe (18, 18') located within the working lining to the internal diameter of the pipe located within the working lining is at least 16.
11. A flushing arrangement according to any one of claims 1 to 10, characterized in that at least two pipes (18) arranged within the working lining (7) of the metallurgical vessel in spaced relationship are flow-connected with a common gas feeding pipe (15) by their ends lying outside of the working lining (7), the insert (26, 34) of each pipe (18) being fastened to said gas feeding pipe (15).
12. A flushing arrangement according to any one of claims 1 to 10, characterized in that two pipes (18) arranged within the working lining (7) of the metallurgical vessel in spaced relationship are flow-connected with a common gas feeding pipe (15) by their ends lying outside of the working lining (7) and that the two pipes (18) have a common insert (26, 34) extending from the mouth of one pipe as far as to the mouth of the other pipe.
13. A flushing arrangement according to any one of claims 1 to 10, characterized in that the insert (26') is fixed in the axial direction on the section of the pipe (18') located outside of the working lining (7).
14. A flushing arrangement according to claim 13, characterized in that the insert (26') is fixed to the pipe (18') by means of at least one supporting rib (32, 33).
15. A flushing arrangement according one of claims 1 to 14, characterized in that the pipe (18, 18') comprises a plurality of inserts.
16. A flushing arrangement according to any one of claims 1 to 17, characterized in that the pipe (18) has a straight pipe section (31) extending at an angle relative to the section of the pipe (18) located within the working lining (7), the insert (26, 34) passing through said straight pipe section.
17. A flushing arrangement according to any one of claims 1 to 16, characterized in that free spaces remaining between the pipe (18, 18') and a working lining formed by refractory bricks are filled with refractory mass (25).

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