| 摘要 |
The thickness of the layer of remaining molten metal at the bottom of a container is measured on tapping molten metal from the container. An alternating magnetic field is generated with a frequency such that the penetration depth ( delta ) in the metal is of the same order of magnitude as the residue thickness of the melt layer of interest for measurement. The alternating magnetic field is generated such that to begin with field components are reflected at a horizontal surface of the melt layer and towards an alternating magnetic field detection position. When the thickness of the melt layer decreases and approaches the residue thickness, less and less field components will be reflected at the surface of the melt and pass instead through the remaining melt layer. The resulting change in detected alternating magnetic field is utilized, e.g. for triggering an alarm or breaking off tapping in some other way. |
