Electro Suspension Magnet Preference for Compost Supplier

A leading UK compost supplier has replaced two permanent suspension magnets with Bunting’s electro suspension magnets.  The additional power of electro suspension magnets enables enhanced separation of small ferrous metals such as nails.

The supplier of compost assessed methods to improve the level of ferrous metal separation for two separate process lines.  Previously installed were two permanent suspension magnets.

After a site review with Bunting’s Technical Sales Engineer Tom Higginbottom, the company ordered two Electro Suspension Magnets to replace the installed magnetic separators and increase the level of ferrous metal separation.

Suspension Electro Magnets

Suspension Magnets extract occasional tramp iron from a conveyed product stream on a conveyor belt or vibratory feeder.  The magnet block is suspended above a conveyor, with sling chains setting the magnet face at the correct angle for optimum extraction.  The Electro Suspension Magnet has a coil mounted inside a steel box and immersed in oil, which keeps the coil cool.  When turned on, the coil produces a strong magnetic field which projects down towards the conveyor and through the transported material.

The magnetic field attracts ferrous metal out of the conveyed material and onto the magnet face, where it remains securely held until manually cleaned.  This ensures end product quality and protects against damage to other processing plant.

The first process line produced a high-grade compost using a mix of compost, derived from green and food waste, and locally quarried sand.  The new Electro Suspension Magnet was mounted above an inclined conveyor, with the face of the magnet approximately 300mm above the lowest point of the rubber belt. 

The second process line produced a high-quality soil using a mix of soil, locally sourced sand, and compost derived from green and food waste.  Once again, the Electro Suspension Magnet was mounted above an inclined conveyor at around 300mm

In both processes, the powerful magnetic field of the Electro Suspension Magnets pulled small ferrous metals (<10mm), including nails, screws, and wire, out of the compost, ensuring the end-product is of pristine quality.

One key benefit of the electromagnetic design is the ability to turn off the power and, therefore, the magnetic field.  On a permanent design the captured ferrous metal has to be manually removed from the magnet face by an operator using gloves and other non-magnetic equipment.  In stark contrast, with the electro design, the conveyor is cleared of product and the magnet is simply turned off.  Without a magnetic field, captured ferrous metal falls down onto the conveyor where it is easily collected and removed before the magnet is turned back on and the process restarted.

“Due to the small size and shape of the iron contamination, the best solution was to replace the permanent designs with Electro Suspension Magnets,” explained Tom.  “The level of separation presently achieved on site is significantly better with the new electro designs.”