Measurements of blast furnace inner-stats by magnetometer

We present in this paper a new and direct method of measuring the inner-state of the blast furnace. The key point of this method is that a number of magnetometers installed in the furnace detect the layers of the ores and cokes through a disturbance in the magnetic field distribution. By processing the outputs from these multimagnetometers, we can obtain various important information to control the blast furnace, such as the falling speed and the thickness of the layers etc.. We have developed a magnetometer suitable for this application, which is made of a small 5 Mo-permalloy film.