| 摘要 |
PROBLEM TO BE SOLVED: To perform a magnetic separation operation efficiently by decreasing the intensity of a magnetic field when the level of accumulation of a magnetic material in a magnetic filter is low and increasing the intensity of the magnetic field when the level of accumulation of the magnetic material is high, by controlling the generated magnetic field of a magnetic separation part during a purifying operation. SOLUTION: During a purifying operation, the generated magnetic field of an electromagnet in a magnetic separation part is controlled through controlling the values of currents supplied from power supplies 42a, 42b and the values of supplied currents are set at a low level when the level of accumulation of a magnetic material in high-gradient magnetic filters 48a, 48b, 48c, 48d is low to lessen the intensity of the generated magnetic fields in superconducting magnets 33a, 33b. Further, when the accumulation layer of the magnetic material increases in thickness, the values of supplied currents from the power supplies 42a, 42b are controlled to set the values of supplied currents at a high level to gradually increase the intensity of the generated magnetic fields in the superconducting magnets 33a, 33b. Thus, it is possible to keep a magnetic power on the accumulation layer at a constant value, regardless of a distance in the thickness direction and, consequently, keep an attractive force for the magnetic material at a constant level. Therefore, the attraction efficiency is enhanced and the purifying efficiency is improved. |
