| 摘要 |
PURPOSE:To detect the height of the melt level of a mold with good accuracy by disposing an AC excitation coil to one side wall in the thickness direction of the mold and a search coil to the other and measuring the induced voltage of the search coil. CONSTITUTION:A circular excitation coil 2 and a search coil 3 are dispospoed opposite to each other with a mold 1 in-between. When AC current of constant amplitude is supplied from an AC oscillator 4 to the coil 2, an AC magnetic field is generated from the coil 2. If the intensity of this magnetic field in the coil 3, the penetration depth of the AC magnetic field, and the diameter and number of turns of the coil 3 are determined, the amplitude of the voltage induced in the coil 3 in correspondence to the level of the melt surface 8 in the mold 1 is determined. After the voltage induced with the coil 3 is amplified to an intended value with a signal amplifier 5, it is converted to DC voltage with a detector 6. This DC voltage is measured with a known means, whereby the level of the surface 8 is measured. |
