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Malvern - Demagnetising Coils for Magnetic Slurry Processing
Demagnetising coils are specialized tools engineered to mitigate the residual magnetism in magnetite and ferro-magnetic materials as they navigate through vertical pipelines, particularly after processing in wet drum magnetic separators. These coils are available in various internal diameters, ranging from 4 to 10 inches, with other sizes offered upon request. Construction involves varnished copper wire wound around a bobbin, protected by epoxy resin against moisture and physical damage, and shielded by laser-cut stainless steel guards. The electrical-grade, non-metallic material used for the bobbin supports operational temperatures between 80° and 95° C, with built-in thermistors set to trigger at 105° C, providing a safe cutoff point. Installation requires the coils to be mounted in a manner that ensures the slurry-carrying pipeline passes directly through the coil center, ideally using non-metallic pipeline materials. Proper setup and maintenance are essential to ensure operational longevity and safety.Demagnetising Coils have been developed to demagnetise Magnetite and Ferro-magnetic medium flowing in a slurry through vertical pipelines, as in the case of concentrate exiting from a Wet Drum Magnetic Separator.
Demagnetising Coils are available in internal diameters of 4, 5, 6, 8 & 10 inch. Various other sizes are available on request.
Construction
The coils, made from varnished copper wire which is wound around a bobbin, are protected from moisture ingress and physical damage by epoxy resin and laser cut stainless steel guards.
The bobbin is made from electrical grade non- metallic material. The coil winding is suitable for operating temperatures of 80° to 95° C and is protected from overheating by thermistors wound into the coil. The thermistors have a maximum cut-off point, pre-set at 105° C and are terminated in an I.P. 55 terminaI box.
A separate (Optional) HDPE pipe is used to transport the slurry medium through the centre of the coil.
General
Whilst demagnetising coils are relatively maintenance free, they should be inspected regularly to ensure they are free of mechanical damage.
If any debris (magnetic / non-magnetic particles) have collected between the bobbin and the pipe conveying the slurry, these must be removed. The magnetic slurry must not be allowed to solidify within the slurry line passing through the demagnetising coil.
INSTALLATION
The demagnetising coil must be mounted so that the pipe conveying the slurry which is to be demagnetised passes through the centre of the coil. The pipeline conveying the slurry medium must be of non-metallic material i.e., HDPE, plastic or rubber etc. As the unit is uniform in design, either end can be used as the in let. The demagnetising coil can be suspended using wire ropes slings or by flanging the slurry line directly to the (Optional) HDPE pipe.
All Connetions are made via a waterproof terminal box mounted on the underside of the coil. The thermistors may be connected to a thermistor relay. Failure to connect in conjunction with a thermistor relay will eliinate any form of overheating protection and may result in possible damage to the coil. The demagnetising coil should be mounted / suspended in such a way that it is protected from falling objects or splashing water.