| 摘要 |
<p>A metal teeming vessel (11) has a sliding gate valve (14) to open and close a teeming passage (12) to metal flow, and a separate installation (15) for injecting gas into the melt before or during teeming. The gas injection installation has a nozzle (16) communicating through the wall (18, 19) of the vessel with its interior and closed off by a solid gas porous plug (22), and a duct for conveying gas to the nozzle (16). The duct terminates at the nozzle in a pair of coacting orificed bodies (26, 27) capable of being mutually positioned so as to shut the duct when the plug (22) shows signs of defectiveness, thus to prevent leakage of molten metal through the installation in the event of failure of the porous plug (22). In particular, the body 26 can be moved laterally with respect to the body 27. <IMAGE></p> |
