| 摘要 |
The invention relates to metallurgy, in particular to design of an apparatus for replacement of a submerged nozzle of a tundish of continuous casting machine. The apparatus comprises a metal housing with a central vertical hole for a socket unit of the tundish and a longitudinal guide slot, it is equipped with means for fixing to the outer surface of the tundish bottom and is placed by upper portion in a metal shell, a changeable refractory submerged nozzle with a vertical channel. The nozzle is movable by a power hydraulic cylinder along the guide slot. The apparatus also comprises a mechanism for pressing the submerged nozzle to the steel-tapping nozzle comprising rotating elements with holes symmetrically mounted on the axles on both sides of the submerged nozzle along its displacement and cinematically interconnected with pre-compressed springs that are mounted in cylindrical channels made in the housing on guide rods with their pressing against supporting collars using plugs screwed into cylindrical channels of plugs. Thus, each rotary element of the apparatus is provided with a finger cantilever mounted thereon bearing a roller that by its rotation surface is contacted with the metal shell of the submerged nozzle, wherein the generatrix of the roller rotation surface is an arc with a radius 0.5b-0, 5d, where b and d, respectively, are the thickness and the outer diameter of the roller in the cross-sectional symmetry, which are related by d/b = 2-2.5. The apparatus provides reduction of the coefficient of friction between the contacting surfaces of the metal shell of a submerged nozzle and through the replacement of sliding friction by rolling friction, it also decreases the required force developed by the hydraulic cylinder during replacement process of submerged nozzles, and consequently the wear of the contact surfaces of rotary elements, and time and material costs associated with the operation and maintenance of the apparatus. |
