Tilting converter

Abstract

A tilting converter comprising a container (2), defining a first longitudinal axis X, having a bottom (2); a support ring (3), coaxial to the container (2) and distanced from said container, provided with two diametrically opposite supporting pins (6), defining a second axis Y orthogonal to the first axis X, adapted to allow a rotation of the converter about said second axis Y; a suspension system, connecting said container (2) to said support ring (3), comprising groups (12) of first suspension devices (7), said groups (12) being arranged substantially equidistant to each other along a cylindrical side surface coaxial to the first axis X, in a position between the support ring (3) and the bottom (2); each of said first suspension devices (7) being provided with a plurality of longitudinal elastic elements, each longitudinal elastic element being arranged alongside the next so as to define a laying plane, and a gap (15, 15) is provided between one longitudinal elastic element and the next.

Claims

1. A tilting converter comprising: a container, defining a first longitudinal axis X, having a bottom; a support ring, coaxial to the container and distanced from said container, provided with two diametrically opposite supporting pins, defining a second axis Y orthogonal to the first axis X, adapted to allow a rotation of the converter about said second axis Y; a suspension system, connecting said container to said support ring, comprising groups of first suspension devices, said groups being arranged substantially equidistant to each other at a cylindrical side surface coaxial to the first axis X, in a position between the support ring and the bottom, characterised in that each of said first suspension devices is provided with a plurality of longitudinal elastic elements rigidly connected by means of their opposing ends to the container and to the support ring respectively, each longitudinal elastic element being arranged alongside the next so as to define a single laying plane for each of said first suspension devices of each group, and a gap is provided between one longitudinal elastic element and the next one in each of said suspension devices of each group; wherein the gap between a longitudinal elastic element and the next is defined by a longitudinal notch passing through the thickness of a flat plate defined by the union of said longitudinal elastic elements arranged alongside, the longitudinal notches being obtained in a central area of said flat plate.

2. A converter according to claim 1, wherein, in each group, the laying plane defined by the plurality of longitudinal elastic elements of one suspension device of said first suspension devices is different from the laying plane defined by the plurality of longitudinal elastic elements of another suspension device of said first suspension devices.

3. A converter according to claim 1, wherein each of said first suspension devices is parallel to the first axis X and tangential to said cylindrical side surface.

4. A converter according to claim 3, wherein said longitudinal elastic elements are parallel to the first axis X.

5. A converter according to claim 1, wherein each of said first suspension devices (7) is inclined with respect to the first axis X.

6. A converter according to claim 5, wherein said longitudinal elastic elements are inclined with respect to the first axis X.

7. A converter according to claim 1, wherein said first suspension devices are restrained at a first end to the container and at a second end to the support ring, preferably by means of locking on respective fastening supports.

8. A converter according to claim 7, wherein all the longitudinal elastic elements of each of said first suspension devices are together rigidly connected by means of a first single fastening support to the support ring and by means of a second single fastening support to the container.

9. A converter according to claim 7, wherein a first fastening support to the support ring is integral with a first surface of the support ring, facing the bottom of the container.

10. A converter according to claim 1, wherein each flat plate is provided with a circular hole at each end of the longitudinal notches.

11. A converter according to claim 10, wherein the circular holes communicate with the respective longitudinal notch and, preferably, have a diameter equal to a value at least ten times the width of the longitudinal notches.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further features and advantages of the present invention will be apparent in light of the detailed description of a preferred, but not exclusive, embodiments of an oxygen converter illustrated by way of non-limitative example, with reference to the accompanying drawings, in which:

(2) FIG. 1 shows a plan view of a converter according to the invention;

(3) FIGS. 2 and 2a show a section taken along the B-B plane of two embodiments of the converter in FIG. 1;

(4) FIG. 3 shows a partial side view of the converter in FIG. 2;

(5) FIG. 4 shows a partial side view of the converter in FIG. 1;

(6) FIG. 5 shows a view of a first embodiment of a component of the converter according to the invention;

(7) FIG. 6 shows a view of a second embodiment of the component in FIG. 5;

(8) FIG. 7 shows a view of a third embodiment of the component in FIG. 5.

(9) The same reference numbers in the figures identify the same elements.

DETAILED DESCRIPTION OF THE INVENTION

(10) The figures show preferred embodiments of an oxygen converter, indicated as a whole by reference numeral 1.

(11) Such a converter 1 comprises: a container or vessel 2, defining an axis X, provided with a loading mouth 4 of the scrap and liquid cast iron and provided with a lateral tapping hole (not shown) of the liquid steel obtained at the end of the conversion process; a support ring 3 for supporting the container 2, said ring 3 being arranged coaxially to the container 2 and appropriately distanced therefrom; two supporting pins or tilting pins 6, known as trunnions, of said support ring 3, arranged diametrically opposite to each other and defining an axis Y, orthogonal to axis X, with at least one of said supporting pins 6 connected to a tilting mechanism (not shown); a suspension system, which connects the container 2 to the support ring 3 and which also performs a centering function between container and ring.

(12) A plane Y-Z, which may be considered an equatorial plane of the converter, and a plane X-Z, both orthogonal to the plane X-Y, are identified by defining a further axis Z as axis orthogonal to the plane X-Y passing through the intersection point of the axes X and Y.

(13) The container 2 comprises a cylindrical central zone 20 and two frustoconical zones 21, 22, each frustoconical zone being arranged laterally with respect to said central cylindrical zone. A first frustoconical zone 21 is welded at an end thereof to said central cylindrical zone 20, while at the other end it comprises the loading mouth 4 of the container. Generally, the lateral tapping hole is provided in said first frustoconical zone 21. A second frustoconical zone 22 is welded at an end thereof to said cylindrical central zone 20, on the opposite side to the first frustoconical zone 21, while at the other end it comprises the bottom 2 of the container 2.

(14) The support ring 3, arranged at the central zone 20 of the container 2, is hollow and preferably has a rectangular cross-section. The ring 3 has a surface 10 facing towards the part of the container comprising the loading mouth 4; a surface 11, opposite to surface 10, facing towards the part of the container 2 comprising the bottom 2 thereof an inner surface facing towards the central part of the container; an outer surface opposite to the inner surface.

(15) With reference to figures from 1 to 4, which show the converter of the invention in the upright position thereof with the loading mouth 4 facing upwards, an advantageous embodiment of the invention includes: a pair of horizontal suspension devices 8, each of which being arranged at a respective supporting pin 6 and transversally with respect to the plane X-Y, and groups 12 of vertical suspension devices 7, said groups 12 being arranged substantially equidistant to each other, at a cylindrical side surface that is coaxial to axis X, in an intermediate position between the support ring 3 and the bottom 2.

(16) In the example shown in the figures, there are provided four groups 12 of vertical suspension devices 7 and each horizontal suspension device 8 is arranged between the two respective groups 12 of suspension devices 7, each group 12 being formed by two suspension devices 7. In other examples, each group 12 may be formed by three or more suspension devices 7.

(17) The four groups 12 of suspension devices 7 are arranged at an equal angular distance between one group and the next (90) so as to obtain a balanced distribution of the loads for each group 12 of suspension devices. The groups 12 of suspension devices 7 are arranged symmetrically with respect to plane X-Z and plane X-Y.

(18) Advantageously, each suspension device 7 of each group 12 comprises a plurality of longitudinal elastic elements rigidly connected by means of their opposing ends to the container 2 and to the support ring 3 respectively, each longitudinal elastic element being arranged alongside the next so as to define a laying plane of the respective first suspension device, and a gap is provided between one longitudinal elastic element and the next.

(19) In particular, each longitudinal elastic element is arranged alongside the next so as to define a single laying plane for each of said first suspension devices 7 of each group 12, and a gap is provided between one longitudinal elastic element and the next one in each of said suspension devices 7 of each group 12.

(20) More in detail, in each group 12 of suspension devices 7, the single laying plane defined by the plurality of longitudinal elastic elements of one suspension device of said first suspension devices 7 is different from the single laying plane defined by the plurality of longitudinal elastic elements of another suspension device of said first suspension devices 7.

(21) In a first variant (FIG. 2), the suspension devices 7 are arranged parallel to axis X and tangential to said cylindrical side surface, and also the longitudinal elastic elements 29 define a longitudinal axis thereof parallel to axis X.

(22) This configuration allows a greater flow of air in the space between the suspension devices 7 and the container 2, and thus also in the space between the container 2 and the ring 3. The air flow which crosses the suspension devices 7 by virtue of the respective longitudinal passages is shown in FIG. 2.

(23) In an alternative variant (FIG. 2a), the suspension devices 7 are arranged inclined with respect to axis X, and also the longitudinal elastic elements 29 define a longitudinal axis thereof inclined with respect to axis X. The inclination with respect to axis X is an angle preferably comprised between 10 and 20.

(24) Each suspension device 7 is restrained at a first end to the container 2 and at a second end to the support ring 3 by means of locking on the respective fastening supports 13, 14, e.g. brackets, by means of fastening means, such as through screws or other equivalent means. In particular all the longitudinal elastic elements 29 of each of said first suspension devices 7 are together rigidly connected by means of a first single fastening support 13 to the support ring 3 and by means of a second single fastening support 14 to the container 2.

(25) Advantageously, a single fastening support 13 and one only fastening support 14 may be provided to fix the ends of the suspension devices 7 of each group 12.

(26) In particular, the fastening support 13 is integral with the surface 11 of the support ring 3, facing towards the bottom 2 of the container; while the fastening support 14 is integral with either the frustoconical zone 22 or both said frustoconical zone 22 and the bottom 2 of the container 2. In the latter case, the greater rigidity of the bottom 2, having a closed, circular structure, is exploited without the need to reinforce the cylindrical zone of the container.

(27) In a first embodiment of the invention, shown in FIGS. 3 and 5, the gaps between the longitudinal elastic elements 29 are defined by respective longitudinal notches 15 passing through thickness of a flat plate defined by the union of said longitudinal elastic elements 29 arranged alongside to each other. Each suspension device 7 is a rectangular-shaped flat plate with rectangular cross-section. The longitudinal notches 15 are obtained in a central zone 16 of the flat plate, intermediate with respect to the ends 17 fixed, e.g. by means of through screws, to the fastening supports 13, 14.

(28) Each flat plate is provided with a circular hole 18 at each end of the longitudinal notches 15. The circular holes 18 communicate with the respective end of the longitudinal notch 15 and, preferably, have a diameter d of value equal to at least ten times the width s of the longitudinal notches 15. Preferably, the width s is comprised in the 1-5 mm range, e.g. 2 mm, and the diameter d is comprised in the 10-40 mm range, e.g. 30 mm. Said circular end holes, made using a machine tool, eliminate the end stresses of the notches due to the stresses induced on the suspensions.

(29) In a second embodiment of the invention, shown in FIG. 6, the gap 15 between one longitudinal elastic element 19 and the next extends for the entire longitudinal extension of said longitudinal elastic elements 19.

(30) The longitudinal elastic elements 19 are flat and have a rectangular transversal section. The ends 23 of each longitudinal element 19 are fixed, for example by means of through screws, to the fastening supports 13, 14. In particular, all the longitudinal elastic elements 19 of each of said first suspension devices 7 are together rigidly connected by means of a first single fastening support 13 to the support ring 3 and by means of a second single fastening support 14 to the container 2.

(31) Advantageously, this solution is the most cost-effective because it allows to use commercial rolled products, no further machining operations are needed and steel with high mechanical properties may be used.

(32) In a third embodiment of the invention (not entirely shown), similar to said second embodiment, the gap 15 between one longitudinal elastic element 19 (FIG. 7) and the next extends for the entire longitudinal extension of said longitudinal elastic elements 19.

(33) In this variant, the longitudinal elements 19 have flat ends 30 having rectangular transversal section and a central body 31 having circular transversal section. Said central body 31 has a diameter greater than the width of the ends 30. The ends 30 of each longitudinal element 19 are fixed, for example by means of through screws, to the fastening supports 13, 14. In particular, all the longitudinal elastic elements 19 of each of said first suspension devices 7 are together rigidly connected by means of a first single fastening support 13 to the support ring 3 and by means of a second single fastening support 14 to the container 2.

(34) This solution is similar to the previous one but each longitudinal element is obtained from a rolled rod instead of having a rectangular cross-section.

(35) The horizontal suspension devices 8 instead are arranged parallel to the plane Y-Z, orthogonal to the first axis X, and symmetric to the plane X-Z. The suspension devices 8 cross the plane X-Y and are arranged near the surface 10 and/or the surface 11 of the support ring 3.

(36) In a first preferred variant, the suspension devices 8 are arranged at a first side of the plane Y-Z, i.e. under the plane Y-Z and the support ring 3 when the converter is in the upright position (FIG. 4). In this case, the suspension devices 8 are advantageously arranged closer to the centre of gravity of the converter to support the load when it is in horizontal position (tapping position).

(37) In a second variant (not shown), the suspension devices 8 are arranged instead at a second side of the plane Y-Z, i.e. above the plane Y-Z and the support ring 3. In a third variant (not shown), two pairs of horizontal suspension devices 8 are provided, a first pair being arranged at a first side of the plane Y-Z and a second pair being arranged at a second side of the plane Y-Z.

(38) The two supporting pins 6, actuated by at least one tilting mechanism, allow the rotation of the converter about axis Y.

(39) The converter usually passes from a first position, in which it is in its vertical position with the loading mouth 4 facing upwards (FIG. 2), to a second position inclined by approximately 30 with respect to the vertical 40, by means of a rotation of the supporting pins 6 in a sense of rotation. In this second position, the liquid cast iron and scrap are loaded through the mouth 4.

(40) The converter returns to the first position in FIG. 2 after loading. One or more nozzles, introduced into the container through the mouth 4, blow oxygen for a given period of time so as to drastically lower the carbon content and reduce the concentration of impurities, such as sulfur and phosphorus.

(41) Once the conversion into liquid raw steel has been completed, the converter passes from the first position shown in FIG. 2 to a third position inclined by approximately 90 with respect to the vertical, by rotating the supporting pins 6 in said sense of rotation. In this third position, the liquid steel is tapped through the tapping hole provided in the container of the converter.

(42) In all variants of the invention, illustrated in the figures, the load, determined by the sum of the weights of the container 2, the liquid cast iron and the scrap, is relieved onto the ground by means of the support ring 3, the vertical suspension devices 7, the horizontal suspension devices 8, the tilting pins 6 and the related supports.

(43) In particular, the configuration of the suspension devices 7 and of the suspension devices 8 allows to absorb the weight at any inclination of the container 2.

(44) The suspension devices 7 act exclusively as tie-rods for an inclination angle of the converter with respect to the vertical equal to 0, while they act only as struts for an inclination angle equal to 180, and gradually both as tie-rods and as struts for different angles from 0 and 180.

(45) The position with inclination angle equal to 180, with the loading mouth 4 facing downwards, is provided for cleaning operations of the container once emptied.

(46) The suspension devices 8 guarantee an optimal support, stability and rigidity of the container. The main purpose of the suspension devices 8 is to support the weight of the container in direction transversal to axis Y when it is inclined by 90 (tapping position) and to support the load component orthogonal to axis X of the converter in all other conditions.

(47) In general, therefore, the load on the suspension devices 7 gradually passes from a maximum value with converter in vertical position to a minimum value with converter in horizontal position, while the load on the suspension devices 8 passes gradually from a value substantially equal to zero to a maximum value when the converter passes from the horizontal position to the vertical position.

(48) The moments which are generated with the rotation of the converter about axis Y are perfectly absorbed by the configurations of the suspension devices 7 and the suspension devices 8.

(49) Various type of the horizontal suspension devices 8 already known in the prior art may be used in the converter object of the present invention.

(50) A first example of suspension device 8, described in WO9525818, has a first structure welded to the container 2 and a second T-shaped structure bolted to the support ring 3. A shim, which allows to adjust the two structures during the step of assembling, is provided at the interface of the welded structure to the container and the T-shaped structure fixed to the ring.

(51) A second example of suspension device 8, described in U.S. Pat. No. 3,653,648, has a first anchor fixed to the container 2 and a second anchor fixed directly to the supporting ring 3. A wedge-shaped shim, fixed in turn by means of screws during the step of assembling of the converter, is provided at the interface between the two anchors, allowing an adjustment of the suspension device exclusively during the step of assembling of the converter.