Bunting have developed a more compact and powerful electromagnetic overband magnet
THE design objective of creating a more compact and powerful electromagnetic overband magnet has led UK-based Bunting, one of the world’s leading designers and manufacturers of magnetic separators, eddy current separators and electrostatic separators for the recycling and waste industries, to develop the new ElectroMax-Plus.
Electromagnetic overband magnets use an oil- or air-cooled wire coil to generate a deep and strong magnetic field. The electromagnetic force radiates from a coil wound around a steel core and mounted inside a steel box with a thick steel back-bar. This focuses the magnetic field in one direction: down towards the conveyed material.
In operation, an overband magnet, suspended over a conveyor, screen or vibratory feeder, will lift and remove ferrous metals such as iron rebar and steel beverage cans.
Overband magnets are a common feature on many mobile screens and crushers. In such applications, minimizing weight and size is crucial, so operators often use standard ceramic ferrite, or, less frequently, neodymium rare earth permanent overband magnets, rather than electromagnets.
Neodymium permanent overband magnets produce a strong but shallow magnetic force and can experience problems with belt and motor damage due to large ferrous metal clamping against the magnet block.
The magnetic field of the light and compact ElectroMax-Plus is both deep and strong, say Bunting, allowing excellent separation performance at higher suspension heights. In addition, simply turning off the electromagnet releases any extremely large entrapped tramp ferrous metal. Also, the shape and nature of this magnetic field means there is less wear to the self-cleaning belt mechanism (eg belt, motor gearbox and bearings).
The new ElectroMax-Plus operates at a 600mm suspension height (the distance between the conveyor belt and the face of the overband magnet), up from 450mm on a standard ElectroMax. At a suspension height of 500mm, the ElectroMax-Plus is more than 105% stronger (in terms of Force Index) than the equivalent ElectroMax, allowing it to remove small tramp ferrous metal commonly missed by permanent overband magnets.
As such, Bunting say the latest ElectroMax-Plus provides companies in the recycling, quarrying and mining sectors with a powerful and compact solution for separating tramp and secondary ferrous metal from conveyors.
‘Companies supplying mobile recycling equipment are requesting stronger and lighter overband magnets,’ explained Adrian Coleman, general manager of Bunting’s Redditch operation. ‘The new ElectroMax-Plus provides a real alternative to neodymium rare earth overband magnets. There is the requested additional magnetic strength, without the operating problems.’
The new ElectroMax-Plus extends Bunting’s comprehensive range of overband and suspension magnets. In additional to standard sizes, Bunting also design and manufacture bespoke models that are application specific.