WO1995025819A1

WO1995025819A1 - Support for a basis steel converter vessel

Info

Publication number: WO1995025819A1
Application number: PCT/GB1995/000600
Authority: WO
Inventors: Michael Hibbs
Original assignee: Davy Mckee Stockton Ltd
Current assignee: Kvaerner Engineering and Construction UK Ltd
Priority date: 1994-03-21
Filing date: 1995-03-17
Publication date: 1995-09-28
Anticipated expiration: 1996-09-21
Also published as: ZA952279B; AU1900495A; GB9405521D0

Abstract

A steel converter vessel (1) must be supported so that it can be tilted from an upright condition to pour the converted steel. To prolong the life of the vessel the support must also accomodate irregular and non-uniform thermal expansion of the vessel. To this end the vessel is secured in a trunnion ring (9) which extends around its vertical axis. Trunnions (13) provide for the ring (9) and hence the vessel (1) to be tilted. To mount the vessel in the trunnion ring (9) three radially extending angularly equally spaced stub-shafts (21) are mounted rigidly onto the vessel (1), each stub-shaft (21) is received into a support assembly (25) having spherical ring bearings (30, 31) which permit the stub-shafts to move in the direction of their longitudinal axis to tilt in the vertical and horizontal planes ant to rotate about its own axis. Thus the thermal stress on the vessel and trunnion ring (9) is alleviated.

Description

SUPPORT FOR A BASIC STEEL CONVERTER VESSEL

The invention may be applied industrially to the support of a steel converter vessel. A steel converter vessel for containing molten iron during its conversion to steel consists of a refractory-lined shell which has a base, a central cylindrical portion and an upper frusto-conical portion leading to an open top. A trunnion ring having a pair of diametrically opposed trunnions surrounds the cylindrical portion of the vessel and is secured thereto. Pivoting the trunnion ring about the trunnions enables the vessel to be tipped.

The support means for the vessel within the trunnion ring must be able to hold the vessel securely within the trunnion ring at any angle of rotation of the ring about the axis of the trunnions.

It will be appreciated that, in use, the vessel will expand and contract and the expansion and contraction is not uniform throughout the vessel. The temperature of the trunnion ring will be very much less than the temperatures to which parts of the vessel are subjected. The support means for the vessel have to be able to accommodate the changes in temperature between the vessel and the trunnion ring.

According to the present invention, a support for a steel converter vessel comprises a trunnion ring having diametrically opposed trunnions about which the ring may pivot to tilt the vessel, at least three radially extending shafts mounted in angularly spaced relation around the vessel to project outwardly, and a number of support assemblies, one each for each shaft, mounted on the trunnion ring, each shaft being received into a corresponding one of the support assemblies, each support assembly permitting the shaft to move longitudinally in the direction of the shaft axis and pivotaly with respect to the trunnion ring.

It is convenient for each support assembly to be secured to the underside of the trunnion ring but they could be secured to the upper side of the ring.

When the vessel is supported with its open top uppermost, the weight of the vessel and its contents is taken on the trunnion ring by the shafts held in the support assemblies. If there is uniform outward expansion of the vessel with respect to the ring, the outward radial movement of the three shafts is permitted by the support assemblies which allow axial movement of the shafts relative to the fixed support assemblies. If the outward expansion of the vessel with respect to the ring is not uniform around the vessel, the axial movement of one or more of the shafts is accommodated by one or more of the support assemblies.

Furthermore, the expansion and contraction of the vessel may be very irregular causing one side of the vessel to move up and down or sideways relative to another side of the vessel. Each support assembly may include arcuate bearing surfaces which permit the shaft to tilt. The arcuate bearing surfaces may be provided by spherical bearing surfaces. The bearing surfaces may permit the shafts to rotate about their axis.

Preferably the shafts are equi-angularly spaced around a vertical axis of the vessel and are mounted on a cylindrical portion of the vessel.

A support for a steel converter vessel embodying the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:-

Figure 1 is a side view of a steel converter vessel and trunnion ring;

Figure 2 is a side view of a support assembly for a basic oxygen furnace;

Figure 3 is a plan view of the support assembly shown in Figure 2 ;

Figures 4 is a sectional side elevation of a second embodiment of the invention having a modified support assembly, and

Figure 5 is a sectional side elevation of a third embodiment.

Referring to Figure 1, a basic oxygen converter vessel 1 comprises a refractory-lined metal shell having a base portion, a central cylindrical portion 3, a frusto-conical upper portion 5 and an open top 7. The vessel 1 is located within a substantially circular trunnion ring 9 having a bottom wall 11 and a pair of diametrically opposed outwardly extending trunnions 13. An annular slag shedder 15 is connected to the top of the trunnion ring 9 and to the vessel 1 to protect the trunnion ring 9 from molten metal.

The vessel 1 is supported within the trunnion ring 9 by means to be described with reference to Figures 2 to 5 which enable the vessel 1 to be held within the trunnion ring 9 when the ring is rotated about the trunnions. Relative expansion between the vessel 1 and the trunnion ring 9 must be accommodated and the vessel 1 must be separable from the ring if necessary.

Three thickened back plates 20 are welded to the cylindrical portion 3 of the vessel 1 and from each back plate 20 a stub shaft 21 extends radially outwardly. The shafts 21 are substantially equally angularly spaced around the vessel 1. A pair of side plates 22 project outwardly from each back plate 20, one on each side of the shaft 21 and a plate 24 is secured to the side plates 22 at the end of the stub shaft and the plate helps to secure the shaft. For small vessels the plate 24 may not be required.

A support assembly 25 is mounted on each of the stub shafts. The assembly comprises a block comprising an upper block 26 and a lower block 27 which are secured together by a plurality of studs 28 which extend through holes in the lower wall 11 of the trunnion ring and through the two blocks. Nuts 29 secured to the upper and lower ends of the studs 28 secure the support assemblies to the underside of the trunnion ring.

Within each support assembly 25 bearing means is provided for receiving the stub shaft 21. The bearing means comprises an inner ring and an outer ring with arcuate bearing surfaces between them. The arcuate bearing surfaces between the outer ring 30 and the inner ring 31 are spherical and will permit each shaft to rotate about its axis.

In the arrangement shown in Figure 4, the outer ring 30 is secured to the blocks 26, 27 and the inner ring 31 is mounted on the stub shaft. The outer ring has a concave bearing surface and the inner ring has a corresponding convex bearing surface and these surfaces allow the shaft to tilt with respect to the blocks 26, 27. The inner ring of the bearing allows the shaft to move axially with respect to the inner ring.

In the arrangement shown in Figure 5, the inner ring 31 is fixed on to the shaft and the outer ring 30 of the bearing is movable axially within a sleeve 32 in the support assembly.^' This bearing also allows both axial movement of the shaft and tilting of the shaft.

The support arrangement permits uniform relative movement between the vessel and the trunnion ring due to expansion and contraction of the vessel and it also permits non-uniform expansion and contraction of the vessel relative to the ring. The vessel can readily be removed from the ring by releasing the nuts 29 on the studs and then lowering the vessel.

It is desirable for one of the stub-shafts on the vessel to be positioned on an axis which is perpendicular to the axis joining the two trunnions to minimise heat transfer to the trunnion ring.

Claims

1. A support for a steel converter vessel comprises a trunnion ring (9) having diametrically opposed trunnions about which the trunnion ring (9) may pivot to tilt the vessel (1) , at least three radially extending shafts (21) mounted in angularly spaced relation around the vessel (1) to project outwardly, and a number of support assemblies (25) , one each for each shaft (21) , mounted on the trunnion ring (9) , each shaft (21) being received into a corresponding one of the support assemblies (25) , each support assembly (25) permitting the shaft (21) to move in the direction of the shaft axis and pivotaly with respect to the trunnion ring (9) .

2. A support according to claim 1 wherein each support assembly (25) is secured to the underside of the trunnion ring (9) .

3. A support according to claim 1 or claim 2 wherein each support assembly (25) includes arcuate bearing surfaces which permit the shaft (21) to tilt.

4. A support assembly according to claim 3 wherein the bearing surfaces are spherical to permit the tilt in both the vertical and horizontal planes.

5. A support assembly according to claim 3 or claim 4 wherein the bearing surfaces in each support assembly (25) are provided by concentric rings (30 31) , the inner ring (31) being mounted onto the shaft (21) and the outer ring (30) being mounted into a block.

6. A support assembly according to claim 5 wherein the shaft (21) is axially displaceable with respect to the inner ring (31) .

7. A support according to claim 5 wherein the outer ring (30) is axially displaceable with respect to the block.

8. A support according to any one of the preceding claims wherein there are only three support assemblies (25) .