Rare earth magnets are strong permanent magnets used in various industries. We use the benefits of the strength of the rare earth magnet to pull tramp metal out of various process flows, collecting ferrous contamination as well as weakly magnetic materials. Rare earth material is Neodymium Iron Boron that is manufactured into a magnetic circuit, arranging the poles to maximize the magnetic reach and holding strength of the magnet. Currently the strongest magnets are available using MgO 52 rare earth material.
Ceramic magnets are mainly composed of strontium carbonate and iron oxide. This magnetic material is less expensive and not as strong as a rare earth material. For collecting large pieces of tramp metal from a process flow, such as bolts and screw drivers, this magnet is a likely candidate for these applications. Typical examples would be plate magnets, overhead magnets and drum pulley magnets.
Grate magnets, or tube magnets, are a perfect way to collect smaller ferrous contamination from a gravity flow or pneumatic flow of material with low ferrous contamination. This magnet is typically provided with rare earth material and pole pieces in the tube to create a very strong magnetic circuit. Grate housings can be manufactured to include EZ clean design or self clean designs.
A drum magnet can be used as a drum separator or a head pulley magnet. In a drum separator, a fixed internal magnet covers an approximate 180° arc inside a rotating drum allowing material to flow over the drum, attracting the magnetic contamination and pulling it out of the material flow on a continuous basis. On a head pulley magnet, the magnetic circuit covers the complete 360° of the drum and uses the belt conveyor belting as the primary means to remove the ferrous contamination from the process. Both these drums can be manufactured using rare earth or ceramic materials.
An overhead magnet is used typically over a belt conveyor system. This magnet can be arranged in line with the belt conveyor (in-line) or perpendicular to the belt conveyor (cross belt). These magnets are available using both electro magnet or permanent magnet designs. The electro-magnet design delivers a deep reaching magnetic field ideal for applications that require increased suspension heights or when a magnet has to protect deep product burdens. Permanent magnets are a good economical solution where equipment protection is required, but where the burden is not as deep and the tramp metal contamination is larger in size. Both of these designs are available in self-cleaning designs where a belt continuously rotates around the magnet to strip any material off the magnet while the unit is in operation.
A plate magnet is a simple magnet that is used either above or below a product flow. This magnet is available in both rare earth and ceramic designs, and can offer a stripping plate to help remove the ferrous contamination. These magnets can have a flushed face or raised pole pieces to hold the tramp metal until it is cleaned from the surface of the magnet. Two plate magnets can be arranged into a hump magnet arrangement to assure contact of the ferrous material with the magnets. A hump magnet can be automated to use an actuator to move the magnet away from the stripper plate to automatically clean the magnet.