METHOD FOR MEASURING LEVEL OF MOLTEN STEEL IN MOLD USING LASER DISTANCE MEASURING APPARATUS

摘要

PURPOSE:To broaden the range of measurement and to very accurately measure the distance to the level of molten steel by measuring the level of molten steel in a mold using laser pulses. CONSTITUTION:A control pulse signal is transmitted from a pulse generator 21 to a laser drive circuit portion 11 and a laser pulse is ejected from a laser emitting portion 12 to the level 3 of molten steel and also to a first light detection element 22. The laser pulse reflected at the level 3 is made to impinge on a light receiving lens 13 via a holed mirror 14 and is transmitted to a second light detection element 23. The ongoing and incoming laser pulses are inputted to a constant ratio-pulse-height discriminator 26 via the elements 22, 23. The detection time at a first transition portion located at 50% of the peak value of each laser pulse is transmitted to a time difference measuring circuit 27 and the difference in the time of arrival between the laser pulses is measured. The difference measured is inputted to a signal processing circuit portion 29, which then computes the distance to the level 3 and displays it on a display 30.