GB2114277A - Metallurgical vessel - Google Patents

Abstract

The outlet channel 5'' from a cylindrical metallurgical vessel is outwardly kinked or curved to prevent the escape of slag along with metal melt following rotation of the vessel into its discharge position. A line t drawn from a point T (where the bottom of the channel meets the internal surface of the vessel) and tangential to the channel bottom 51 (or extrapolating the bottom) intersects the channel top 53. <IMAGE>

Description

SPECIFICATION Metallurgical vessel It is known for molten metal to be transported in a cylindrical, refractory lined vessel which is rotatable about a horizontal axis in order to discharge the melt. Generally, such a vessel is supported on bogies with flanged wheels running on the tracks of a steelworks railway system.

In the case of the vessel disclosed in German Patent No. 19 36 770, metal is charged into and discharged from the vessel by way of openings at the top of the vessel. In practice, the slag is first poured off into a receptacle before the molten metal is poured into a ladle.

However, the problem arises that some of the molten metal escapes with the last of the slag, and slag residues are carried along during the initial flow of molten metal. This contamination adversely affects the required composition of the poured melt.

To overcome this problem, it has been proposed to fit a retaining edge in the inlet opening close to the side wall of the vessel so as to form a discharge channel between the vessel wall and the retaining edge, see Journal of Metals, August 1971, "Tap Holes in Hot Metal Torpedo Cars", page 23, Fig. 1 0.

When pouring iron, the retaining edge should in theory retain the slag. With this arrangement, the retaining wall is located in the nozzle, that is to say at the very top of the vessel. This makes it difficult to maintain the necessary lateral clearance from the track rails during pouring. Moreover, the conditions for filling the vessel are impaired by such a wall arrangement. In addition, it is not possible to keep the slag away from the liquid iron in the final phase of the pouring process, i.e. in the extreme tilted position.

The present proposal is to provide a metallurgical vessel which permits complete, slag-free pouring of the molten metal while ensuring high reliability in the operation. Accordingly, it is proposed that the vessel should have at least one discharge channel disposed to one side of a filling opening in the upper region of the vessel, the discharge channel being so arranged that, when viewed as a longitudinal section of the channel, an extrapolation of a straight portion of its bottom joined to the internal contour line of the vessel wall, or a tangent to the bottom at the point where it meets the internal contour line, intersects the top of the discharge channel. In use, the vessel may be supported on a chassis provided with flanged wheels to enable it to travel along a railway track.In the pouring position, the discharge channel is then so arranged that its outlet is located at a moderate lateral distance from the track rails. To discharge the melt, the vessel is rotated about its horizontal axis as a function of the falling surface level of the metal but at such an angular velocity that a large proportion of a slag layer on the melt is retained on the vessel wall during the pouring of the melt. The proposed arrangement enables the molten metal to be poured completely from the vessel, the slag being delayed in the discharge channel during the last phase of the pouring process, but being retained by the wall of the channel. Once the pouring of the metal has ended, the remaining slag can be discharged into another vessel.

In the drawings: Figure 1 shows a vessel in accordance with the present proposal in cross-section, the lower right hand corner of the drawing depicting part of the vessel in the tilted, pouring position, and Figure 2 is a view similar to Fig. 1 but of a modified vessel with a curved discharge channel.

Disregarding for the moment the detail shown in the bottom right hand corner of the Figure, a cylindrical vessel is shown in its travelling position, and comprises a casing 1 with a lining 2. The vessel is mounted on a chassis for rotation about an axis A in bearing races, neither the chassis nor the bearings being shown. The vessel may be filled through an opening 4 in its top and discharged through either of two discharge channels 5, 5' adjacent the opening 4. By duplicating the discharge channels in this way, the vessel may be rotated clockwise or counterclockwise around the axis A and discharged to either side.

During transportation, the approximately cylindrical interior space 3 in the vessel is filled with liquid metal on which floats a slag layer. The discharge channels are sealed by removable covers 8 which prevent the melt from splashing. Sliding seals may be used instead. During the discharge of the melt through one of the channels, the other remains sealed.

In the bottom right hand corner of the Figure, the discharge channel 5 is shown in the position 5" which it occupies during discharge of the melt through this channel. It will be appreciated from this that each discharge channel is arranged in such a way that its outlet is located at a moderate lateral distance from the track rails in the pouring position. The lowest point 71 on the mouth of each channel where it opens to the exterior of the vessel, is arranged to be at a level above the upper extremity of the interior space 3 of the vessel when the vessel is in its normal, untilted travelling position. This arrangement prevents the melt from flowing out of the vessel immediately after opening the cover 8 since the space 3 is in permanent communication with the discharge channels.

To enable the metal melt to be discharged completely while the slag is retained within the vessel, the bottom 51 of each channel (considered in the discharge position and viewed in a longitudinal section of the channel) has a straight portion 51 which is tangential to the inner surface 31 of the vessel in the region from which the channel extends. An imaginary extrapolation of the portion 511 intersects the top 53 of the discharge channel. The channel may, of course, be circular in cross-section, so that the portion 511 is a line drawn along the lowest part of the channel parallel to the channel axis. Alternatively, however, the bottom of the channel may be inclined outwardly at an acute angle to a tangent taken to the internal contour line 31 at the junction T between the bottom and the inner surface 31 of the vessel.Nevertheless, it is still necessary for the extrapolation of the portion 511 to intersect the top 53 of the discharge channel 5. As illustrated, the straight portion 511 of the bottom merges into an outwardly curved portion 512, and a straight portion 531 of the top 53 merges into an outwardly curved portion 532.

During the pouring process, the vessel should rotate during tilting about the axis A as a function of the falling surface level of the metal bath at such an angular velocity that extensions of planes formed by the upper side and by the lower side of the slag layer 9 intersect the wall of the furnace vessel. In the initial phase of the tilting process, therefore, the slag is retained between the points 7 and 11 in the cross-section of the vessel, and then on the top of the channel through which discharge takes place.

In the modification illustrated in Fig. 2, the discharge channel is curved outwardly. In this case, a tangent t to the bottom of the channel taken at point T intersects the channel top 53.

Claims (10)

1. A substantially cylindrical, lined metallurgical vessel supported for rotation about a horizontal axis, the vessel having an upper filling opening and at least one discharge channel provided to the side of the filling opening in the upper region of the vessel, the or each discharge channel being so arranged that, when viewed as a longitudinal section of the channel, an extrapolation of a straight portion of the bottom of the channel which meets the internal contour line of the vessel wall or a tangent to the bottom of the channel and the point where it meets the internal contour line, intersects the top of the discharge channel.

2. A vessel according to claim 1, wherein the straight portion of the bottom of the discharge channel is tangential to the internal contour of the vessel.

3. A vessel according to claim 1, wherein the straight portion of the bottom merges into an outwardly inclined or bent portion.

4. A vessel according to claim 1, wherein the bottom and the top of the discharge channel are curvilinear.

5. A vessel according to any preceding claim, wherein the discharge channel is sealed by a removable spray protection cover.

6. A vessel according to any of claims 1 to 4, wherein the discharge channel is sealed by a sliding seal.

7. A vessel according to any preceding claim, wherein the vessel includes a plurality of discharge channels arranged opposite each other, symmetrically to the vertical plane running through the axis of the vessel in its normal or travelling position.

8. A substantially cylindrical, refractory lined metallurgical vessel having an upper filling opening and at least one discharge channel circumferentially spaced from the filling opening, the channel being curved or kinked away from the filling opening, so that a line drawn from the point where the lowest part of the channel meets the internal surface of the vessel intersects an upper wall portion of the channel.

9. An approximately cylindrical lined vessel arranged rotatably about a horizontal axis for metallurgical purposes, in particular for a rail-borne vehicle for the transportation of liquid metal on which there floats a layer of slag, with an upper filling opening as well as at least one discharge channel provided to the side of the filling opening in the upper region of the vessel which is arranged in such a way that, in the pouring position, its outlet is located at a moderate lateral distance from the rails, the vessel being rotated about its horizontal axis as a function of the falling surface level of the metal bath at such an angular velocity that a large proportion of the slag layer is retained on the vessel wall during the pouring of the molten metal, characterised in that, when viewed as a longitudinal section of the discharge channel 5 and 5', the extension of a straight portion 511 of the lower edge 51 of the discharge channel 5" joined to the internal contour line 31 of the vessel wall at a junction T or a tangent taken to the lower edge line 51 at this junction intersects the upper edge 53 of the discharge channel 5".

10. A vessel substantially as illustrated in Fig. 1 or Fig. 2.