Design of power magnetic chute separator and minimization of its external magnetic field

Magnetic chute separator is a device for extracting ferrous particles from dry bulk materials. The material falls down through a chute with strong transverse magnetic field generated by permanent magnets or field coils carrying DC current. Ferrous particles are then attracted to the walls of the chute where the magnetic field reaches the highest value. In order to prevent the field from penetrating outside the device, it is necessary - with respect to the existing hygienic standards - to use appropriately designed shielding satisfying, of course, acceptable construction and financial requirements. As the magnetic field is practically stationary, it is reasonable to use only passive shielding elements. The paper deals with the design and optimization of shielding elements of a typical separator of this type with two field coils, whose principal arrangement is depicted. The problem is treated as a fully 3D task.