Overband magnet

Overband magnets are used to automatically remove magnetic foreign matter from bulk materials. A distinction is made between permanent magnets and electromagnets. Permanent magnets are maintenance-free and have an unlimited service life. The magnetic field is permanently effective and cannot be interrupted. In electromagnets, the magnetic field is generated by an electric coil. This can be switched on or off as required, for example for maintenance and servicing.

The overband magnet is placed at a specific distance above the conveyor belt. The magnet, which is protected by a wear-resistant plate, attracts the iron particles from the bulk material. If the overband magnet is equipped with a discharge belt, the foreign objects stick to the underside of the belt and are continuously removed by the circulating belt equipped with carriers. Since the area of the deflection and drive drum is not magnetic, the parts fall off in this zone and are collected via chutes or containers.

Special design measures ensure that the overband magnet is magnetically shielded on all sides, i.e. there are no interfering stray fields that could attract iron parts to the sides and possibly influence electromagnetic control units. This shield also serves as protection against mechanical destruction, strong demagnetising fields and as accident protection for operating personnel.