Stopper for reliable gas injection

摘要

The present invention concerns a mono-block stopper adapted to deliver gas during pouring of molten metal comprising a stopper body having an internal chamber (1) and a gas discharge port (2), a bore (3) connecting the internal chamber (1) to the gas discharge port (2), calibrating means (4) being provided in the bore (3) to provide a restricted path. This stopper is characterised by the fact that the calibrating means comprise a rod (4) having at least one axially-extending gas passages therealong, the gas passage(s) having a section such as to offer a predetermined resistance to flow. The stopper of the invention is far more reliable and can be easily adapted to various operational parameters.