Magnets Ain’t Magnets

Supplier: Serpent & Dove - Applied Magnetics
18 September, 2009

The cartoon image of a horse-shoe shaped magnet picking up a car* has, for many, defined magnets. Or perhaps it’s been the magnet that holds stuff on the fridge. To most, a magnet is just a magnet, but this is not the case.

In industry, different magnetic field configurations, types and shapes are used for different applications. Magnetic fields can be designed to be intense and shallow or with a series of close North/South/North/South poles. This configuration is often used for magnets that lift or clamp, especially for thin steel. Magnets designed with a broad, deep-reaching field are used to attract objects from a distance. This is the type of magnetic field more likely to be employed in magnetic sweepers or various magnetic separators for food, chemical or mining industries.

In mining and extraction industries, large permanent or electro magnets are employed over conveyor belts to remove damaging iron (known as ‘tramp iron’) from materials as diverse as coal, iron ore, gravel, mineral ores and grain. Tramp iron is the enemy of downstream crushing or grinding equipment and finds its way into product streams from many sources. It can be as diverse as nuts and bolts to train wheels, crow bars, spanners, bucket teeth, chain, roof bolts and fencing wire. Getting it out is a specialty of Serpent and Dove® and requires an understanding of the dynamics of conveyed product, taking into account all the factors such as the speed of the belt, the product size, density and moisture content and the size of tramp iron likely to cause problems. Magnets applied over conveyors can be of self-cleaning or manually cleaned types and for particularly difficult applications, Serpent and Dove, with many years experience in this specialised field, can frequently recommend a number of unusual but highly effective means to ensure that magnets are used to their maximum effect.

Since 1984, magnet specialist, Serpent and Dove® has been successfully designing and supplying magnets and magnetic equipment. Applications range from permanent and electro magnets for steel lifting applications, to magnets to clamp pilot ladders or oil-spill booms to ship hulls, magnets to retrieve items from sea-bed drill holes, specialised rare earth magnets to clean up food, grain, chemicals and ore, magnetic head pulleys and tramp iron magnets for conveyor belts, magnetic conveyors, magnetic clamps for the welding industry and magnetic floor sweepers. Serpent and Dove’s motto is, ‘Finding ways with Magnets’.

* By the way – the only way a magnet can pick up a car is by using a thick steel plate under its roof. A vehicle roof is no-where near thick enough for any magnet (no matter what size) to act effectively on and lift such a weight. If you’ve seen a whole (uncrushed) car lifted with a magnet – that’s the trick.