| 摘要 |
PCT No. PCT/CH87/00161 Sec. 371 Date Aug. 31, 1988 Sec. 102(e) Date Aug. 31, 1988 PCT Filed Nov. 27, 1987 PCT Pub. No. WO88/04209 PCT Pub. Date Jun. 16, 1988.A stopper (6), secured to the lower end of a stopper rod, carries a plug (13) having a radial throttle aperture (14) above which a frustoconical shut-off surface (16) is located. The frustoconical surface fits against a valve seat surface 18 of an outlet tube (3) from a vessel, to form a first seal. A further seal is provided by an annular surface (19) of the plug (13) engaging in the outlet passage. The stopper (6) is rotatable so that the direction of flow of the molten metal from the vessel (1) and, passing through the stopper-when raised-can be influenced, if desired continuously during flow of the melt. This provides flow control and a safe shutoff of metal flow. The formation of vortices in the molten metal is largely prevented, thus avoiding the carrying along of slag.
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