Metallurgical apparatus – Process – Plugging or tapping
Reexamination Certificate
1999-04-08
2001-04-03
Kastler, Scott (Department: 1742)
Metallurgical apparatus
Process
Plugging or tapping
C266S237000, C222S590000, C222S592000
Reexamination Certificate
active
06210629
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a process for the discontinuous tapping of melts, e.g. metal melts such as liquid steel, or fusible non-metals, from a vessel through a passage. Furthermore, the invention relates to an arrangement for carrying out the process.
During the discontinuous tapping of the melt, the melt outflow is intentionally interrupted while the vessel remains more or less filled, in order to start the tapping operation at a subsequent time. After the interruption of the melt outflow, the melt freezes in the passage and forms a plug there. The plug must be removed before the renewed tapping operation can begin. According to the prior art, the plug is melted by an oxygen lance. For this purpose the lance must be guided from below the vessel which is a dangerous operating process.
A discontinuous tapping of melts takes place, for example, in disposal melting installations.
SUMMARY OF THE INVENTION
It is an object of the invention to provide an operationally safe tapping operation and a corresponding arrangement.
The above object is solved by performing a tapping operation in which the melt flow is interrupted at the outlet of the passage such that it solidifies within the passage. Renewed tapping results when the interruption is ceased and the solidified melt is melted by applying radial electromagnetic energy thereto.
The melt flow is stopped by actuating the interruption. The melt is subsequently allowed to solidify in the passage, whereby a reliable double closure of the vessel is attained. To start in the melt flow again, the interruption is ceased and the melt plug is melted by applying radial electromagnetic energy thereto. This operation is also operationally safe since the use of an oxygen lance is no longer necessary.
During the renewed tapping, the interruption can be ceased first and subsequently the solidified melt can be melted. However, preferably the renewed tapping occurs as a result of first melting the solidified melt in the passage and then ceasing the interruption. This is possible because the melting does not take place through an oxygen lance, but rather through application of radial electromagnetic energy. This approach has an advantage in that the solidified melt on the structural part forming the interruption is melted before the structural part is moved mechanically. Movement of the structural part is thus not hindered by the solidified melt.
The application of the electromagnetic energy preferably takes place by inductively coupling an electromagnetic filed to the solidified melt and/or to the passage. If the melt is a metal melt, it becomes coupled intrinsically to the electromagnetic field of an inductor. However, it is also possible that the passage comprises an inductively couplable material In this case, the energy is transferred to the melt through thermal conduction and/or heat radiation.
In a further development of the invention, the cooling and solidification of the melt in the passage after the interruption of the melt flow by virtue of cooling an inductor provided for the application of the electromagnetic energy is assisted by electrically switching off the inductor. Thus, a melt plug blocking the passage is formed rapidly.
In order to prevent the melt plug from bursting the passage during the melting, the melting of the solidified or completely rigidified melt plug takes place so rapidly that a thin margin zone or the melt plug is liquified before a temperature equalization occurs throughout the melt plug. Through the melt plug expanding during the melting, the liquified material of the margin zone is displaced upwardly or downwardly such that the passage does not burst due to the expansion of the melt plug. The danger of the passage bursting can also be eliminated by heating the passage just in advance of the frozen melt such that the passage expands to such an extent that the melt melt plug expands into the additional space created by heating the passage. In this case, the passage comprises a material which becomes inductively coupled to the electromagnetic field of the inductor due to the high temperature of the melt e.g., a ceramic material.
An arrangement for carrying out the described process is characterized in that in a melting vessel is disposed a passage, in particular a sleeve, whose exit can be closed and opened by virtue of a known mechanical adjusting element arrangement. The passage is surrounded by an inductor, in particular an air-cooled inductor whose electromagnetic filed becomes coupled directly to the melt and/or the passage. Thus, because the passage itself is surrounded by the inductor, it is ensured that the melt plug is subjected to the electromagnetic energy.
The known adjusting element arrangement can be a plate with an aperture and a closing face. It can also comprise a blind plate and an aperture plate or nozzle.
For electromagnetic shielding of a metal mounting with which the arrangement is fastened on the vessel, ferrite cores can be provided.
REFERENCES:
patent: 5348566 (1994-09-01), Sawyer et al.
patent: 5350159 (1994-09-01), Parker
patent: 5939016 (1999-08-01), Mathiesesn et al.
patent: 5968447 (1999-10-01), Pavlicevic et al.
patent: 1049547 (1959-01-01), None
patent: 3427940 (1986-02-01), None
patent: 4428297 (1996-02-01), None
Ardell Richard
Bruckner Raimund
Grimm Daniel
Didier-Werke AG
Kastler Scott
Wenderoth , Lind & Ponack, L.L.P.
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