Electromagnetic atomisation of molten metals - via rapidly rotating magnetic field in nozzle through which metal flows

摘要

The molten metal or alloy is fed down a stationary tube (a) with a small outlet hole (b) in its bottom end; and the melt is rapidly rotated inside tube (a) by a rotating magnetic field created by a fixed stator surrounding tube (a). The result is that fine droplets of metal leave hole (b) as a cone of spray with its apex in hole (b). The pref appts. used a tube (a) with an axial calibrated hole (b); and stator coils fed with 3-phase electric current and possibly using magnetic pole pieces or circuits; or the coils may consist of tubular conductors fed with oil for removing heat. Tube (a) may be made in two parts. The process and device is used esp. to mfr. metal powder or shot of controlled size, or for collecting the drops on a cooled support or drum to mfr. sheet or tubes. The process can be also used to achieve chemical or physical transfers between the droplets and a gas, e.g. for oxidin.; removal of oxide; or degassing.