Metallurgical apparatus – Means for melting or vaporizing metal or treating liquefied... – Bessemer-type treating vessel
Reexamination Certificate
1999-09-21
2001-05-08
Kastler, Scott (Department: 1742)
Metallurgical apparatus
Means for melting or vaporizing metal or treating liquefied...
Bessemer-type treating vessel
C266S245000
Reexamination Certificate
active
06228320
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates generally to a tiltable converter having a trunnion ring surrounding a converter vessel, the converter vessel being supported on the trunnion ring by a mounting system.
2. Description of the Currently Available Technology
Tiltable converters are known in the art. The support system must enable the converter vessel to thermally expand and contract unimpeded in the radial and longitudinal direction. The converter vessel is known to grow globally (material creep), to locally distort and change its shape when subjected to elevated temperature during operation. Such changes in form could affect the loads imposed on the support system members unless the system is statically determinate. This determinacy is desirable to better enable designing the members to the loads applied on them.
A statically determinate tiltable converter is disclosed in U.S. Pat. No. 5,364,079, which is herein incorporated by reference. In this tiltable converter, the converter vessel is connected to the trunnion ring by six or seven pendulum rods, with spherical plain bearings located at each end of each rod. The seven rod design, under conditions of converter vessel distortion, would be rendered statically indeterminate, whereas the six rod design, with three Alongitudinal@ pendulum rods extending substantially parallel to a longitudinal axis of the converter vessel and three Atansverse@ pendulum rods extending substantially parallel to the plane of the trunnion ring would be statically determinate. However, additional improvements could be made to further enhance the design and/or performance of this tiltable converter.
SUMMARY OF THE INVENTION
Whereas U.S. Pat. No. 5,364,079 specifically teaches that all of the pendulum rods are located below the trunnion ring, the present invention teaches relocating the transverse pendulum rods, especially those oriented in the neighborhood of the rotational axis of the converter, above the trunnion ring to provide a multiplicity of design and operational advantages. The added gains in the arrangement of the transverse pendulum rods above the trunnion ring are most applicable to those converters which must necessarily have openings for process gas conduits and piping, of substantial diameters, which need to circle unhindered around the converter vessel before they can be directed to the converter bottom. Also, the relocation of the transverse pendulum rods above the trunnion ring removes them from an area in the converter exposed to heat from hot accumulating slag and known for potential break-outs by molten contents inside the converter in case of refractory failure. Placing the transverse pendulum rods above the trunnion ring additionally assists in balancing the converter by raising its center of gravity closer to the axis of rotation, thus lowering the torque requirement to tilt the converter.
The present invention provides a converter which possesses the aforementioned advantages in addition to those advantages disclosed in U.S. Pat. No. 5,364,079. Relocation of the transverse pendulum rods can be achieved without a major increase in their size or the general design of the mounting system. Because a statically determinate mounting system is desirable, it becomes necessary to consider the six link system comprising three longitudinal and three transverse pendulum rods. Since the same equations apply for determining the loads in the link system when the transverse links are below the trunnion ring as when the transverse links are above the trunnion ring, the present invention teaches that there is no compelling reason to follow the dictates of U.S. Pat. No. 5,364,079 which teaches placing the transverse links exclusively below the trunnion ring. Specifically the static determinacy is not violated by placing the transverse pendulum rods above the trunnion ring. As will be understood by one knowledgeable in the art, one transverse link system, particularly that which is oriented substantially in the direction of the axis of rotation, may be retained to provide lateral stability to the converter vessel within the trunnion ring. However, an alternate manner of providing the needed lateral support in accordance with the invention is by providing a stabilizer which restricts the lateral motion of the converter vessel with respect to the trunnion ring in the direction substantially parallel to the axis of rotation, while allowing the converter vessel to thermally expand in the radial and longitudinal directions. This embodiment will, therefore, provide a six component mounting system comprising five links and one stabilizer. These six components provide a statically determinate system.
A preferred embodiment of a converter incorporating features of the invention comprises a converter vessel carried on a trunnion ring by a mounting system. The mounting system includes six mounting components or elements which include a plurality of, e.g., five, mounting elements incorporating pendulum rods and one mounting element comprising a stabilizer device. Each pendulum rod is connected at one end to the trunnion ring and at the other end to the converter vessel, preferably by spherical bearings. In a preferred embodiment of the invention, the mounting system comprises six elements including three first mounting devices, each having a first pendulum rod; two second mounting devices, each having a second pendulum rod; and a stabilizer device. The first mounting devices and the stabilizer device are preferably located below or on the lower side of the trunnion ring and the second mounting devices are preferably located above or on the upper side of the trunnion ring when the converter vessel is in an upright position. A statically determinate mounting of the converter vessel in the trunnion ring is thus accomplished with five pendulum rods and one stabilizer device.
A complete understanding of the invention will be obtained from the following description when taken in connection with the accompanying drawing figures, wherein like reference characters identify like parts throughout.
REFERENCES:
patent: 3561744 (1971-02-01), Altman
patent: 4061318 (1977-12-01), Fisher
patent: 5364079 (1994-11-01), Gruber et al.
“The VAI-CON Link Suspension System for LD/BOF Converters” Dec. 1995.
Daum Thomas
Enkner Bernhard
Gruber Rudolf
Nagati Rashed
Staudinger Guenther
Kastler Scott
Voest-Alpine Industries, Inc.
Webb Ziesenheim & Logsdon Orkin & Hanson, P.C.
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