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NKK(Nippon Kokan,Japan)对连铸机结晶器钢水液面自动测量系统的改进取得了进展。这个系统的特点是利用涡流来进行检测。 通常,结晶器钢水液面是用手工测量或用放射性同位素、热电偶来进行自动测量。然而,这些方法在测量精度、安全和操作上都有不足之处。 NKK的改进方法是引入一个正反馈放大器,从而克服了这些缺点。高频电流经正反馈放大器流到检测线圈,并形成高频磁场。当这磁场接触到钢水表面,钢水内部产生电动力,并在钢水中有涡流流动。由于感应的作用,涡流又产生新的磁场,检测线圈的感抗是随磁场的变化而变化的,故可用检测线圈的感抗值来反映这涡流的大小。而涡
NKK (Nippon Kokan, Japan) made progress in the improvement of the automatic liquid level measuring system for the continuous casting mold steel. The characteristic of this system is the use of eddy currents for testing. Normally, the mold liquid level is measured manually or with radioisotopes and thermocouples. However, these methods have deficiencies in measurement accuracy, safety and operation. NKK’s improved method is to introduce a positive feedback amplifier, thus overcoming these shortcomings. High-frequency current flows through the positive feedback amplifier to the detection coil, and the formation of high-frequency magnetic field. When this magnetic field comes into contact with the surface of the molten steel, the molten steel generates electric power inside and there is vortex flow in the molten steel. Due to the induction effect, the eddy current generates a new magnetic field. The inductance of the detection coil changes with the change of the magnetic field. Therefore, the inductance of the detection coil can be used to reflect the size of the eddy current. And vortex