| 摘要 |
<p>Gas injection into a metal melt, accompanied if desired by powdered or solid treatment substances, is by way of a nozzle (14) inserted into the wall (12) of a melt-containing vessel (10). The nozzle bore (18) initially has a stopper (20) at its inner end and a delivery pipe (24) smaller than the bore (18) is movable therein. Before injection, the pipe (24) and bore (18) adjacent the stopper (20) are cooled by gas. By thrusting the pipe (24) against the stopper (20) while sufficient gas flow and pressure is maintained, the stopper is dislodged and the gas will enter the melt as a jet which leaves the pipe (24) at a velocity equalling or exceeding Mach 0.5. Melt enters the clearance between the pipe (24) and bore (18) but, due to the pre-injection cooling, rapidly freezes locking the pipe safely in the bore. </p> |
