Immersion lance consisting of two concentric tubes - esp. for injecting powder into molten iron or steel and using two tubes with the same outlet bore dia.

摘要

The lance is immersed in a molten mass, esp of steel or iron, and is used to inject powders below the surface of the melt. The ratio of the dias. of the outlet ends of the outer tube and the inner tube is near to unit; and the length of the lance contg. both materials being injected is similar to the dia of the oulet end of the outer tube. The bore of the outlet end of the outer tube is pref. 5-30 mm dia., whereas the length (L) of the lance contg. both materials is pref. 10-20mm, esp ca. 15mm. The inner tube pref. ends in a conical nozzle tapering inwards, a similar nozzle being fitted on the end of the outer tube. Used esp where the inner tube is used to feed a powder into a gas stream supplied by the outer tube, where the gas stream protects the lance from the melt.