Just like overband separators, permanent magnetic – or electromagnetic – drums are self-cleaning iron removers installed outside a conveyor system.
The use of magnetic drums is recommended when customers need an accurate extraction of ferrous intrusions from process material in order to preserve other machineries (eg. shredders/blades) within the waste plant.
The drum structure and type of magnets varies according to the dimensions of the ferrous fractions to be recovered.
A permanent magnet drum does not require an electric panel to function. Malaman C.T.C. supplies its permanent magnetic drums ready for installation and operation. On the contrary, an electromagnetic drum requires an electrical panel dimensioned according to the magnet’s winding circuit.
Iron removers (eg. overbelt separators, manual overhead suspension magnets, magnetic drums, etc.) are used in the first stage of refining the process material such as glass, wood, plastic, post-combustion slag, USW, OFMSW, etc.
A magnetic drum is made up of:
MAGNETIC DRUMS: FURTHER DETAILS
For magnetic drums up to Ø 600mm, the gearmotor is directly mounted onto the rotating half-shaft.
For larger magnetic drums, instead, a transmission chain is used to transfer motion from the motor shaft to the rotating half-shaft.
In a magnetic drum, the motor shaft transfer motions to the rotating half-shaft which is fixed to one of the two flanges constituting a single body with the other flange and rotating cylindrical shell.
The internal magnetic circuit is oriented so as to hold the ferrous material onto the cylindrical shell. This shell is equipped with transversal cleats welded onto its surface which help carrying the Fe intrusions away from the magnetic field and then release them into bins for collections.
Malaman C.T.C. suggests two different installation options:
The magnetic field of a magnetic drum can be:
If necessary, the permanent and electromagnetic nature of the inductor field can be mixed together.
The differences between the two types of magnetic field can be summed up as follows: