| 摘要 |
<p>Lance for injecting fluid materials into molten metals, the novelty being that it consists of metal pipe fitted with several continuous longitudinal grooves with an element linking the outer ends of the grooves, and anchoring devices are fixed to the element which extends along the pipe. At least three grooves are pref. provided, whereas the element is pref. a spiral of barbed wire wound round the grooves, the barbs forming the anchoring devices. The grooves may be an integral part of a pipe made by extrusion, or be located on the pipe by welding. In the pref. mfg. process, vibration moulding is employed to locate a refractory sleeve round the pipe. For example, the removal of sulphur from molten iron in a transfer ladle, using calcium carbide in nitrogen as a carrier gas. The lance is inexpensive to make and has a long working life.</p> |
