EP0403466A2 - 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 forming a wear lining and with pipes through which flushing gas flows through at predetermined locations of the refractory lining.

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 separation of non-metallic inclusions and promotes a certain degassing of the molten metal.

A variety of devices are known for introducing purge gas. For example, the Radex-Rundschau, Issue 3, 1981, pages 499 to 517; EP-A-0 053554 and EP-A-0 032350 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 purging stone, which has a sheet metal jacket enclosing a porous refractory mass to avoid lateral gas leakage, the porous mass being able to be provided with a directed porosity, thus replaces a conventional stone of the wear lining of the converter. The sheet metal jacket is open towards 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 is not completely in contact with the sheet metal jacket. Furthermore, such a sink has wear that is premature compared to the wear lining of the converter, so that it is material and time-consuming Repair measures between two new linings of the wear lining are required.

Furthermore, it is known (AT-B-265 341) to embed a nozzle pipe in a refractory sink, but this has the disadvantage that the sink, which is also used instead of a conventional refractory lining of the converter, always with a certain A 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 further known (EP-A-0 043338, EP-A-0 021861 and EP-A-0 043787) to form a sink from several refractory individual parts with little or no porosity, the individual parts being formed by a sheet metal jacket So-called sandwich sink, which is also installed instead 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 which 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, premature wear cannot be ruled out, since the refractory individual parts have a different composition than the refractory stones of the Vettchleiß 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. Expansion of the stone when the metallurgical vessel heats up can result in crushing and thus a reduction in the amount of purge gas.

EP-B-0 064449 discloses a flushing device of the type described in the introduction, in which a plurality of flat-pressed tubes starting from a distributor located outside the vessel are passed through the converter jacket and the permanent lining and in recesses which are cut into adjacent stones of the wear lining, are used. 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 braced with 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-lining of the vessel is necessary.

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

The invention aims at avoiding these disadvantages and difficulties 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 prevents penetration of melt into the tubes 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.

This object is achieved in that at least one rod-shaped insert which extends in the longitudinal direction of the tube and which forms an annular gap with the inner wall of the tube is provided centrally in each tube.

It is known from EP-B-0 064449 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 section into two or more interior spaces.

Preferably, the part of the pipe lying in the wear lining and the insert used therein are radially symmetrical, as a result of which thermal expansions are distributed evenly over the cross section, so that the stress on the wear lining caused thereby is evenly distributed over the circumference of the pipe.

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.

According to preferred embodiments, the insert is formed from a wire or from a wire rope. It is also possible to form the use of an inner tube through which oxygen can optionally be introduced.

Preferably, the insert in the part of the pipe lying in the wear lining is loose, i.e. provided without lateral support and only fixed in position in the axial direction with respect to the tube. When gas is passed through the pipe, the insert is automatically centered in the pipe so that there is always an annular gap between the inner wall of the pipe and the insert during gas flushing.

A preferred embodiment is characterized in that the fixation of the insert relative to the tube has little play in the axial direction. 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).

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

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 inner diameter of the pipe.

The ratio of the length of the pipe lying in the wear lining to the inner 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 .

A preferred embodiment that is easy to manufacture is characterized in that at least two tubes, which are arranged at a distance from one another in the wear lining of the metallurgical vessel, have a common end with their ends lying outside the wear lining 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 in 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 tube to the mouth of the other tube.

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.

In this case, the insert can expediently be 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 relative 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, FIG. 1 a longitudinal section through a steelworks converter, FIG. 2 a plan 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. In FIGS. 10 to 13 different cross-sectional shapes of tubes and inserts are shown.

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 which open into the longitudinal joints 11 between adjacent rows 10 and each abut a side face of a stone of an adjacent row 10.

Flushing devices 14 are used 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 in 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 arch part 20. These arch parts 20 of the distributor pipes 18 are located in the permanent lining 4 just below the wear lining 7. The arch parts 20 merge into straight-line pipe parts 21 with a circular cross section, the distance 22 of which approximately corresponds to the thickness 23 of a stone 6 corresponds to the wear lining 7. A 6 'of the stones 6 of the wear chuck 7 has at the corners in cross-section corresponding to the cross section of the tubular parts 21 formed recesses 24 which receive the tubular 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 the 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 inner 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 u. 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 piece 31 of the distributor pipe 18 branching off from the feed pipe 15, so that the distributor pipe is prevented from tearing off. This rectilinear 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 location of the introduction of the feed pipe 15 , is required.

According to the embodiment shown in FIG. 7, the insert 26 is also U-shaped and extends in the case of fork-shaped distributor pipes 18 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. This is the use 26 fixed so far in the axial direction that it cannot be pressed 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 straight from the outside through the metal outer jacket 1 and entire refractory lining of the steel mill converter is guided. The fixation of the insert 26 'relative to the tube 18' takes place 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 into 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 control 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 several flushing devices can be operated with a control element acting together and not, as before, each flushing device - as a result of the frequent growth of a conventional flushing device - on its own must be controllable. 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 (20)

1. Flushing device for a metallurgical vessel, in particular for a steelworks converter, with a refractory lining that forms a wear lining (7) and with pipes (18, 18 ') through which flushing gas flows at predetermined locations of the refractory lining, characterized in that centrally in each Tube (18, 18 ') at least one rod-shaped insert (26, 26', 34) extending in the longitudinal direction of the tube (18, 18 ') is provided, which forms an annular gap (30) with the tube inner wall (29). 2. Flushing device according to claim 1, characterized in that the part of the tube (18, 18 ') lying in the wear lining (7) and the insert (26, 26', 34) inserted therein or the inserts inserted therein are radially symmetrical. 3. Rinsing device according to claim 1, characterized in that the tube (18, 18 ') has a circular cross section. 4. Flushing device according to claim 1, characterized in that the tube (18, 18 ') has a cross section formed by a regular polygon, preferably a square or hexagonal cross section (Fig. 10, 12). 5. Rinsing device according to one or more of claims 1 to 4, characterized in that the insert (26, 26 ', 34) is formed by a wire. 6. Rinsing device according to one or more of claims 1 to 4, characterized in that the insert (26) is formed by a wire rope (34) (Fig. 13). 7. Flushing device according to one or more of claims 1 to 4, characterized in that the insert (26, 26 ') is designed as an inner tube. 8. Flushing device according to one or more of claims 1 to 7, characterized in that the insert (26, 26 ') in the part of the tube (18, 18') lying in the wear lining is loose, i.e. is provided without lateral support and is only fixed in position in the axial direction with respect to the tube (18, 18 '). 9. Flushing device according to claim 8, characterized in that the fixation of the insert (26, 26 ', 34) relative to the tube (18, 18') has a slight play in the axial direction. 10. Rinsing device according to one or more of claims 1 to 9, characterized in that the annular gap (30) has a width between 1 and 3 mm. 11. Flushing device according to one or more of claims 1 to 10, characterized in that the inner diameter of the tube (18, 18 ') between 4 and 12 mm, preferably between 4 and 8 mm, and the diameter of the insert (26, 26' , 34) is between 2 and 8 mm, preferably between 2 and 5 mm. 12. Flushing device according to one or more of claims 1 to 11, characterized in that the tube (18, 18 ') has a wall thickness which corresponds to approximately half the inner diameter of the tube. 13. Flushing device according to one or more of claims 1 to 12, characterized in that the ratio of the length of the tube lying in the wear lining (18, 18 ') to the inner diameter of the tube lying in the wear lining is at least 16. 14. Flushing device according to one or more of claims 1 to 13, characterized in that at least two tubes (18) which are arranged at a distance from one another in the wear lining (7) of the metallurgical vessel, with their ends lying outside the wear lining (7) a common gas supply pipe (15) are connected in terms of lines, the insert (26, é34) of each tube (18) being fixed to the gas supply tube (15) (FIGS. 5, 6). 15. Flushing device according to one or more of claims 1 to 13, characterized in that two tubes (18) which are arranged at a distance from one another in the wear lining (7) of the metallurgical vessel, with their ends lying outside the wear lining (7) with one Common gas supply pipe (15) are connected by line and that the two pipes (18) have a common insert (26, 34) extending from the mouth of one pipe to the mouth of the other pipe (Fig. 7). 16. Flushing device according to one or more of claims 1 to 13, characterized in that the insert (26 ') on the outside of the wear lining (7) lying part of the tube (18') is fixed in the axial direction (Fig. 8, 9 ). 17. Flushing device according to claim 16, characterized in that the insert (26 ') by means of at least one support rib (32, 33) on the tube (18') is fixed. 18. Rinsing device according to one or more of claims 1 to 17, characterized in that the tube (18, 18 ') has a plurality of inserts. 19. Flushing device according to one or more of claims 1 to 18, characterized in that the tube (18) has a straight tube part (31) extending at an angle to the part of the tube (18) lying in the wear lining (7), through which the insert (26, 34) extends (Fig. 5 to 7). 20. Flushing device according to one or more of claims 1 to 19, characterized in that between the tube (18, 18 ') and a wear lining made of refractory stones remaining spaces are filled with refractory mass (25).

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