| 摘要 |
The invention concerns an immersion-lance for introducing a finely-particulate solid material into a metal melt, by means of a carrier gas, the internal diameter of the lance being narrowed in the region of the outlet opening. The object in the invention is to produce a lance which is suitable both for the transport of solid material and for flushing with gas. This is achieved by the features that the lance (1) contains a restrictor (8) which can be moved coaxially with the outlet opening (3), this restrictor being located, in a first end position, at a distance from the outlet opening (3) such that an open cross-section remains which is suitable for the transport of the solid material, and this restrictor being located, in a second end position, so that it narrows the outlet opening to a cross-section suitable for the transport of the gas. When the restrictor is located in the second end position, it narrows the outlet opening to a residual cross-section which is so small that the desired quantity of gas passes through the residual cross-section at a pressure, or velocity, such that the molten material is prevented from penetrating.
|
