| 摘要 |
PROBLEM TO BE SOLVED: To improved the accuracy of molten method injection stopping control by detecting the surface level in a mold in real time with an ultrasonic sensor immediately before the stop of the molten metal injection, and to achieve the surface property improvement of case products, the floating of enclosure and the improvement of quality by controlling the casting speed. SOLUTION: Ultrasonic wave transmitted from an ultrasonic sensor 1 enters a mold 7 through a reflecting plate 3. The wave is reflected from a reflecting plate 2, which is set on powder 10 of a molten metal surface 9, and receiving by the sensor 1. The received signal is amplified 4, and the noises are removed with a majority filters 5. The signal corresponding to the level of the molten metal surface 9 is indicated 6. Since the received and amplified level signal is the hunting noise, the detected indication value is not stable. The noises are removed until the digital indication by the filter 5. In the filter 5, the hunting signal is regarded as the noise when the hunting signal is less than a reference number for a specified time, the noises is disregarded and the previous signal value is held. When the reference number is exceeded, the signal value at the time of exceeding is made to be the detected value. |
