TAP ON A METALLURGICAL VESSEL, IN PARTICULAR ON AN ELECTRIC ARC FURNACE

Abstract

A tap on a metallurgical vessel, in particular an electric arc furnace, is provided with a refractory end brick (6) that has an outlet opening (10). There is assigned to the lower face surface (11) of the end brick (6) a slot (15) which is shaped such that with the latter a tear-off edge (16) is generated on the outlet opening (10) when emptying the vessel. This slot (15) is annular in form and is provided here with a radially outwardly inclined inclined surface (18), and this tear-off edge (16) is thus formed immediately following the outlet opening (10). Thus, after each tapping process, the tap can be cleaned without manual assistance by shearing off with the front edge of the plate of the closure device.

Claims

1. A tap on a metallurgical vessel, in particular an electric arc furnace, with a refractory end brick (6) that has an outlet opening (10), characterized in that there is assigned to the lower face surface (11) of the end brick (6) a slot (15), which is shaped such that with the latter a tear-off edge (16) is generated on the outlet opening (10) when emptying the vessel.

2. The tap according to claim 1, characterized in that the slot (15) is annular in form and is provided thereby with a radially outwardly inclined inclined surface (18) which, as viewed in cross section, runs at an angle (17) of between 5° and 20° relative to the face surface (11) of the end brick (6), and this tear-off edge (16) is thus formed immediately following the outlet opening (10).

3. The tap according to claim 2, characterized in that the inclined surface (18) of the slot (15) is preferably inclined at an angle (17) of approximately 17° relative to the face surface (11) of the end brick (6).

4. The tap according to claim 1, wherein the slot is in the form of a part circle, preferably approximately half, and surrounds the outlet opening concentrically.

5. The tap according to claim 1, wherein depending on the dimensions of the tap, the slot has a radial width of 2 to 10 cm.

6. The tap according to claim 1, wherein the slot, which is made with a triangular cross section, is rounded on the side facing away from the tear-off edge.

7. The tap according to claim 1, wherein the slot is surrounded radially by at least one additional slot.

8. The tap according to claim 7, characterized in that both slots (15, 15a) are dimensioned with approximately the same profile or have different dimensions.

9. A refractory end brick for a tap according to claim 1, with an outlet opening, characterized in that there is assigned to the one face surface a slot which is shaped such that a tear-off edge is formed with said slot on the outlet opening.

10. The refractory end brick according to claim 9, characterized in that the slot (15) is made in the form of a circle or part circle and surrounds the outlet opening (10) concentrically.

11. The refractory end brick according to claim 9, wherein the slot is provided when shaping the end brick or is milled into the end block.

12. The refractory end brick according to claim 9, wherein edging is provided on the other face surface of the sleeve-like end brick in order to center the end brick.

13. The tap according to claim 2, wherein the slot is in the form of a semicircle and surrounds the outlet opening concentrically.

14. The tap according to claim 3, wherein the slot is in the form of a semicircle and surrounds the outlet opening concentrically.

15. The tap according to claim 2, wherein the slot has a triangular cross section and is rounded on the side facing away from the tear-off edge.

16. The tap according to claim 3, wherein the slot has a triangular cross section and is rounded on the side facing away from the tear-off edge.

17. The tap according to claim 4, wherein the slot has a triangular cross section and is rounded on the side facing away from the tear-off edge.

18. The tap according to claim 5, wherein the slot has a triangular cross section and is rounded on the side facing away from the tear-off edge.

19. The tap according to claim 2, wherein the slot is surrounded radially by at least one additional slot.

20. The tap according to claim 3, wherein the slot is surrounded radially by at least one additional slot.

Description

[0015] In the following the invention will be explained in more detail by means of exemplary embodiments with reference to the drawings. These show as follows:

[0016] FIG. 1 is a top view of an electric arc furnace for the production of steel;

[0017] FIG. 2 is a longitudinal section of the electric arc furnace according to line II-II in FIG. 1;

[0018] FIG. 3 is a diagrammatically illustrated crown-like frozen steel slag layer on an end brick according to the prior art;

[0019] FIG. 4 is an end brick according to the invention, shown in section;

[0020] FIG. 5 is a detail V of the end brick according to FIG. 4, shown enlarged, and

[0021] FIG. 6 is a section of another version of an end brick according to the invention.

[0022] FIG. 1 and FIG. 2 show a metallurgical vessel provided as an electric arc furnace 1 with three implied electrodes 2 and a tap 3 for the emptying of the latter. The electric arc furnace 1 is arranged here such that it can tilt so that the molten metal produced can be let out without leaving any residue. This tap 3 with a tapping channel 10 is contained in the refractory lining 1′ in the bottom of the furnace. The mode of operation of this electric arc furnace 1 is not discussed any further because this is known.

[0023] In principle, instead of an electric arc furnace 1 a different metallurgical vessel may also be provided, for example a converter or a tilting furnace for non-ferrous molten metal.

[0024] The tap 3 is formed from a number of sleeve-like refractory individual segments 5 lined up alongside one another and from an end brick 6 projecting from the furnace at the bottom and which is detachably fastened in a holding flange 7. The individual segments 5 and the end brick 6 are produced from a refractory material here, for example burnt or carbon-bonded magnesite or clay brick.

[0025] In FIG. 3 this type of three-dimensional crown-like frozen steel slag layer 14 is shown diagrammatically as an illustration, which on the known end bricks forms on the lower face side in every tapping process.

[0026] Before the start of a melting process the tapping channel 10 has to be closed every time so that it can be filled with filler sand. The closure is achieved by means of a closure device, the plate of which closes the tapping channel 10 at the outlet. Perfect closure is not guaranteed if frozen steel slag layers produced in the outlet region of the end brick 6 have built up and block the closure device.

[0027] In order to prevent this, the end brick according to the invention as shown in FIG. 4 and FIG. 5 is provided with a slot 15 running round the outlet opening and which forms a sharp tear-off edge 16 in the face surface 11 of the end brick 6. This prevents rounding of the outlet surface from occurring here which encourages the formation of frozen layers. Preferably, this tear-off edge 16 is formed immediately following the outlet opening 10.

[0028] As can be seen in FIG. 5, the slot 15, as seen in cross-section, is configured such that it has an inclined surface 18 that is inclined radially to the outside at an angle 17 of between 5° and 20°, preferably 17°, relative to the face surface 11 of the end brick. The radial width 19 of the slot 15 is from 2 to 10 cm, preferably 5 cm. The slot 15 is rounded on the side 20 facing away from the tear-off edge 16. It can be milled either by pressing the end brick or subsequently in the finished end brick.

[0029] The described geometry of the slot 15 has proven to be optimal if the tap is working under normal operating conditions. However, it goes without saying that it is also possible within the framework of the invention to vary the slot profile to a specific degree depending on the conditions of use if it guarantees the formation of a sharp tear-off edge without having any perceptible negative impact upon the structural stability of the end brick.

[0030] According to FIG. 6, as a variation of an end brick, provision can be made to increase the effect of the slot 15 by providing in the face surface 11 of the end brick at least one additional slot 15a which surrounds the slot 15 and is preferably formed with approximately the same profile.

[0031] The invention is sufficiently demonstrated by the above exemplary embodiments. Needless to say, it could also be explained by other versions. Thus, a slot with barely a part circle could be assigned to the lower face surface of the end brick. The end brick with the slot would have to be fitted here by this holding flange onto the electric arc furnace such that upon tilting the furnace, approximately half of the end brick would be provided with the slot or the tear-off edge on which the molten mass flows out.