Why Do Crossbelt Magnets Need Armored Belts?

It’s no surprise that the crossbelt (overband) magnet experiences the most wear and tear on the belt that transfers separated metal away from the conveyor. In order to reduce the damage to this rubber belt, Bunting has developed a special, lightweight armored belt for crossbelt magnets. Bunting stands as a global leader in the design and manufacture of magnetic separators, eddy current separators, metal detectors, and electrostatic separators. Its global manufacturing facilities are located in Newton, Kansas just outside the city of Wichita in the center of the United States.

Armored Belts Protect Crossbelt Magnets from Excessive Wear and Extend Belt Lifespan 

Positioned over a conveyor that transports materials like aggregate, waste, shredded wood, or mined ore, crossbelt magnets operate by creating a magnetic field, either through a permanent magnet or an electromagnetic block. This field attracts ferrous metal from the conveyed material onto the revolving self-cleaning belt. Rubber upstands on the belt catch the lifted metal, and transport it away from the conveyed material into a separate collection area.

The force generated when ferrous metal strikes the self-cleaning rubber belt is considerable, due to the magnetic attraction increasing as the metal approaches the magnet’s face. Consequently, the metal accelerates into the belt, momentarily sandwiching the moving belt between the lifted metal and the magnetic block until the upstand catches and removes the item from the magnetic field.

Applications where self-cleaning belts experience significant wear:

• High levels of ferrous metal in the conveyed material.

• Large and heavy ferrous metals.

• Nails, or thin and sharp ferrous metals.

• Models that have additional force in their magnetic block (like the ElectroMax and ElectroMax-Plus)

To prevent excessive wear and prolong belt lifespan of crossbelt magnets, Bunting’s engineers devised a lightweight, yet heavy-duty, armor for the belt. While alternative options such as special wear-resistant belt coatings and other rubber belt types exist, the armor offers unparalleled protection, significantly extending belt life.

This armor consists of high-density polyethylene (HDPE) slats, each measuring 100mm in width and 10mm in thickness, tailored to fit the specific crossbelt magnet model. These slats are affixed to the belt using special 304 stainless steel elevator bucket bolts and nyloc nuts.

Adrian Coleman, Bunting’s Technical Director in the UK, says, “The introduction of this design of armored belt has proven very popular. Other types of belt armor have proven unsuccessful, but the HDPE has worked exceptionally well.”