DE1246001B - Vacuum container for degassing metal, especially iron and steel melts - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

LIBRARY

OF THE GERMAN PATiHTAKfIS

Int. Cl .:

C21c

German class: 18 b -7/08

Number: 1246 001

File number: D 41883 VI a / 18 b

Filing date: July 2, 1963

Opened on August 3, 1967

The invention relates to a vacuum container for degassing metal, in particular from Iron and steel melt, which consists of a refractory lined and sheet metal-sheathed vessel and is filled and emptied from the bottom. In the known partial quantity degassing is in the bottom of the Vacuum container is also a sheet-metal-clad and refractory-lined tubular suction nozzle arranged, the free end of which is immersed in the metal to be degassed. Through periodic lifting and lowering of the vacuum container, the metal is sucked in via the suction nozzle and, after degassing, to the Pan melt returned. In the case of the known continuous degassing, a vacuum container is in the bottom two separate nozzles arranged, one of which the metal to be degassed in the Container conveyed and the other discharges the degassed metal from it.

In the known vacuum containers, the vacuum-tight connection between the container and Suction nozzle great difficulties, which are caused by the fact that on the one hand when the nozzle is attached a vacuum-tight connection between the steel jacket of the nozzle and that of the container and on the other hand a connection that is as intimate as possible, if not absolutely vacuum-tight must be made between the refractory lining of the nozzle and the container. These Difficulties result from the different thermal expansion of the materials and from the fact that the refractory lining of the nozzle naturally always turns out somewhat different and therefore not always connects exactly to the refractory lining of the container.

A device for the continuous casting of steel is known from US Pat. No. 2,837,790 which the melt is poured into a vacuum vessel via a funnel, the outlet nozzle of which is a barometric Downpipe is formed and connected to a continuous casting mold. Between the barometric Downpipe and the mold a bellows is arranged, which is a non-releasable, so coupling-less forms resilient or movable connection between the two axially movable cylindrical bodies. It does not matter that the connection is vacuum-tight because it is in the bellows Protective gas is being worked.

The object underlying the invention is to design a vacuum container and the associated suction nozzle on the installation side so that a vacuum-tight as well as an intermediate vacuum container for degassing metal,
especially of iron and steel melts

Applicant:

Dortmund-Hörder Hüttenunion
Corporation,
Dortmund, Rheinische Str. 173

Named as inventor:

Dr.-Ing. Karl Brotzmann, Sulzbach-Rosenberg

Claimed priority:

Japan July 3, 1962 (37-36 503)

see whose refractory lining the closest possible connection can be made. To the Solution to this problem is proposed, two adjustable in distance, by a flexible wall part, about a bellows to provide connected flanges, the lower of which is fixed to the steel jacket of the nozzle is connected, while the upper is the connecting member for the releasable, vacuum-tight compression forms with the container, wherein clamping means are provided, by means of which the flanges against one another can be pulled until the refractory lining of the nozzle matches that of the container is full. That by means of this arrangement it is possible to master the difficulties mentioned the explanation of the illustrated exemplary embodiment will result.

The clamping means, which are generally in the form of clamping bolts with nuts, can be used at the same time form the means for relieving the refractory material from the axial pressures caused by the buoyancy acting on the submerged nozzle. For this purpose, the clamping devices can be used with special shoulders or stops on which the buoyancy acts supports standing nozzle from below.

Further features of the invention will be explained with reference to the illustrated embodiment.

The drawing illustrates a longitudinal section through the lower part of a designed according to the invention Vacuum container.

Of the actual vacuum container in which the degassing takes place, only part of the outer steel jacket 1 and also part of the refractory lining 2 drawn. The container encloses a chamber 3 which is closed on all sides and which is to be evacuated and heated. The bottom of the Container has an opening 4, at the mouth of which a

709 619/474

Claims (4)

downwardly protruding suction nozzle 5 is to be connected. This nozzle is immersed in a pan standing under the container and containing the metal to be degassed, from which the metal is sucked into the chamber 3 under the effect of the vacuum. The suction nozzle 5 consists of a steel jacket 6 with a refractory lining and casing. The dressing? consists of refractory rammed earth and the inner lining consists of a layer 8 of corundum bricks. A fine-grain filler 9 is located between the latter and the steel jacket 6. The lining 8 forms the continuation of the refractory lining of the container. It is therefore important to bring the upper end face 10 of the lining 8 into full contact with the lower end face 11 of a refractory ring stone 1 a surrounding the opening 4, which is part of the container lining 2. In addition, a vacuum-tight connection must be made between the steel jacket 6 of the nozzle 5 and the steel jacket 1 of the container. To achieve this, there are two flanges 12 and 13 on the nozzle 5. The flange 12 is welded to the steel jacket 6 and connected to the flange 13 by a steel bellows 14, which is a vacuum-tight, flexible wall element between the flanges. A number of screw bolts 15 are firmly screwed into the flange 13, distributed around the circumference, which protrude through holes in the flange 12 and are provided with nuts 16 and 17 on both sides of this flange. The flange 13 can be screwed to a flange 19 welded to the steel jacket 1 of the container by means of pivot bolts 18. Between the flanges 13 and 19 there is a sealing washer 20, which consists for example of steel asbestos. If the connector is to be changed, the screw connections on the pivot pin 18 are loosened and the connector to be replaced is separated from the container. With the nuts 16 loosened and considerably screwed down, the new socket is brought into contact with the flange 19 with its flange 13 after the seal 20 has been inserted, and the pivot pin 18 is connected to the latter in a vacuum-tight manner by tightening the nuts. However, as a result of the nuts 16 being screwed down, there is currently no contact between the end faces 10 and 11 of the refractory linings. The heating of the vacuum container is then switched on and operated until a thermal steady state has set in, i.e. all parts have expanded to the extent that it corresponds to the operational state. Despite the different expansion coefficients of the materials, there are no dangerous thermal stresses. Once the thermal steady state has been reached, the nuts 16 are tightened. As a result, the connecting piece 5 is raised until a close contact is established between the end faces 10 and 11 of the refractory linings on both sides. This procedure guarantees that the refractory lining of the suction nozzle will not be damaged during the degassing of the melt. Due to its resilience, the bellows 14 enables the surfaces 10 and 11 to rest snugly in spite of the frequently unavoidable deviations in the axial dimensions of the linings of the suction nozzles. Even if the end face 10 of the lining 8 turns out to be crooked, a clean connection is always achieved as a result of the bellows 14 and the individual bolts 15 distributed around the circumference. The nuts 17 located on the bolts 15 are only screwed down to the flange 12 and tightened when the connecting piece 5 has been fixed by means of the nuts 16 in the manner described. The nuts. 17 serve to absorb the axially upwardly directed buoyancy forces acting on the nozzle 5 when immersed in the melt, thus relieving the surfaces 10 and 11 of these forces. It may be advisable to evacuate the space 21, which is located inside the steel jacket but outside the refractory lining, via a nozzle 22, which is conveniently connected to the main vacuum line, and thus to ensure that the pressure in this space is maintained is practically the same as that inside the vacuum vessel. Without the evacuation, the pressure in space 21 is naturally always slightly higher than in the vacuum container, so that a small gas flow occurs between surfaces 10 and 11, which is undesirable. Patent claims: 1. Vacuum container for degassing metal, in particular iron and steel melts, with a suction nozzle which is used for immersion in the melt and is detachably connected to the container and which consists of a steel jacket with a refractory lining and cladding, with the steel jacket of the container and A vacuum-tight connection can be made to the steel jacket of the nozzle, characterized by two flanges (12, 13) which are adjustable in their distance and are connected by a flexible wall part (14) known per se, of which the lower one (12) is fixed to the steel jacket (6). of the nozzle (5) is connected, while the upper (13) forms the connection member for the releasable, vacuum-tight connection (18,19,20) with the container, clamping means (15) being provided by means of which the flanges (12,13 ) can be drawn against each other until a connection between the refractory lining (2.2 ä) of the container and that (8) of the nozzle (5) is established. 2. Vacuum container according to claim 1, characterized in that the spam means (15) adjustable stops (17) are provided, on which the under the effect of buoyancy standing nozzle (5) is supported from below. 3. Vacuum container according to claim 1 or 2, characterized in that the clamping means of several bolts (15) distributed around the circumference with clamping nuts (16, 17) are formed. 4. Vacuum container according to one of claims 1 to 3, characterized in that the Space (21) outside the refractory lining and inside the steel jacket can be evacuated separately is. Considered publications:
U.S. Patent No. 2,837,790. 1 sheet of drawings 709 6W474 7.67 © Bundesdruckerei Berlin DRAWINGS SHEET 1 Number:
Int. α .:
German class:
Display day: 18 b -7/08 3rd August 1967 709 619/474