CA1165358A

CA1165358A - Tap-hole covering device for electric metal-smelting furnace

Info

Publication number: CA1165358A
Application number: CA000360272A
Authority: CA
Inventors: Hannsgeorg Bauer; Erich Heinrich; Helmut Meyer; Josef Otto; Klaus Von Ploetz; Ralf Schneider; Manfred Walter; Ludger Zangs
Original assignee: Mannesmann Demag AG
Current assignee: Mannesmann Demag AG
Priority date: 1980-09-11
Filing date: 1980-09-11
Publication date: 1984-04-10

Abstract

ABSTRACT

In an electric metal smelting furnace having a crucible with at least one tap-hole arranged in the bottom thereof, said tap hole being equipped with a driven closure comprising a metal plate adapted to be applied to the tap-hole from below, the plate being attached to a lever member secured to a shaft mounted laterally below the crucible, the shaft being actuated by a rotary drive.

Description

3~1~

The invention relates to an electric metal-smelting-furnace having at least one tap-hole arranged in the bottom and equipped with a driven closure.
Most electric reduction-furnaces are equipped, near the bottom, with tap-holes closed by means of a tap-hole gun which forces an appropriate plastic compound into the tap-hole.
At tapping time this plastic compound must be bored or burned out. Closing, and more particularly, opening the tap-hole takes up a certain amount of time, since the gun or drill must first be placed in position. Furthermore, sufficient room must be available in the vicinity of the tap-hole to move these machines.
In the case of casting ladles, it is already known to provide the discharge-aperture with a sliding closure. Known designs make use of a stationary plate arranged upon the ladle and having an aperture across which a second, mobile plate, also equipped with an aperture, may be slid. When the ladle is to be emptied, the apertures in the two plates are brought into alignment, whereas sliding the mobile plate, laterally, closes the outlet.
In this design, the plate must fit closely together, to prevent any molten metal getting between them and impairing the seal be-tween them. ~owever, this is not always avoidable. Even the use of a device which presses the mobile plate against the stationary plate provides no permanent improvement.
It is therefore the purpose of the invention to improve an electric metal-smelting-furnace of the type mentioned at the beginning hereof in such a manner as to permit the molten metal to be tapped faster and with fewer problems than has hitherto been possible. According to the invention, this purpose may be achieved by means of the characteristics set forth in the claims.

i53~3 It has already been demonstrated in practise that the use of a simple closure in the form of a flap considerably shortens the tapping time. Since the plate which closes off the tap-hole is pivoted out of the path of the molten metal during tapping, no wear phenomena are observed. The surface against which the Elap bears in the closed position may be designed in such a manner that the molten metal flowing through the aperture does not impinge upon it. After tapping, and before the new heat is initiated, it is desirable to fill the tubular tap-hole passing through the furnace lining with a bulk material, e.g. sand, which bakes together under the heat of the molten metal, thus preventing the latter from acting directly upon the closure flap. This material may be such that it disintegrates as soon as the closure flap is opened, thus freeing the tap-hole.
A preferred embodiment of the invention is illustrated in the drawing attached hereto, wherein:
Fig. 1. is a side elevation of the device according to the invention;
Fig. 2. is a plan-view of the arrangement according to Fig. l;
Fig. 3 to 6 are various vertical cross-sections through Fig. 2.
As shown in Fig. 1, located on the bottom of the crucible of an electric metal-smelting furnace is a tap-hole 1 terminating in a tubular connection 3 projecting from bottom 2 of the crucible under which is arranged a drive 4 to which is secured a flap 4 bearing, in the closed position, against tap-hole 1.
' As may be seen in Fig, 2, a horizontal shaft 6, displaced laterally in relation to tap-hole 1, runs under the furnace crucible.

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Arranged approximately centrally are two parallel levers 7 connected to the said shaft, the actual closure-plate 5 being secured to the said levers. Shaft 6, and the sai~ closure flap, is actuated by means of a piston-cylinder unit 8 which - according to Fig. 2 - eomprises a piston-rod engaging with lever 9 secured to shaft 6~ -the other end of the said unit being hinged to the furnace-crucible.
~ ocated at the other end of the said sha~t is a locking device 10 consisting of a seeond piston-eylinder unit 11 whieh, when flap 5 is in the closed position, sli~es a wedge 12 into the path of an eccentric pin 13, thus locking shaft 6.
Fig. 3 shows the arrangement of the drive used to open and close the bottom closure. The design of the closure-flap, and the fitting thereof to the levers secured to the shaft, may be seen in Fig. 4 in which the said flap is shown in the closed posltlon.
Fig. 5 shows longitudinally displaeeable wedge 12 which seeures the bottom-elosure in the elosed position, the said wedge enga~ing, in the position shown, under an eccentric pin secured to the said shaft. The longitudinal motion of the web is produeed by piston-eylinder unit 11 shown in Fig. 2 and incorporated parallel with the direetion of motion of the said wedge.
Fig. 6 shows the bottom-closure in the open position.
If the eleetric metal-smelting furnace is to be equipped with a plurality of tap-holes in the bottom, or in the vicinity of the bottom, for example beeause a sump is to be maintained during tapping, there is no problem in fltting a pl~lrality of the compact flap-elosures according to the invention.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. An electric metal-smelting furnace having a crucible with at least one tap-hole arranged in the bottom thereof, said tap-hole being equipped with a driven closure comprising a plate adapted to be applied against the tap-hole from below, said plate being attached so as to allow restricted movement to a first lever secured to a shaft mounted laterally of the tap-hole and below the crucible, said shaft being actuated by a drive means in the form of a rotary drive comprising a pressure-actuated cylinder-piston unit, one end of which is hinged to a stationary part of the furnace, while the other end thereof is hinged to a second lever secured to the shaft, and wherein the plate and shaft are adapted to be held in the closed position by locking means comprising a wedge adapted to be moved into the path of an eccentric pin connected to the shaft, said wedge being in communication with the mobile part of a cylinder-piston unit arranged on the furnace.

2. An electric smelting-furnace according to claim 1, wherein control-means are provided to actuate the cylinder-piston unit of the locking means in the unlocking direction when the flap-opening procedure is initiated and in the locking direction after the said flap has been closed.