MAGNETIC TUBES AND GRATE MAGNETS

The magnetic tubes are static iron removers that are used to extract fine-iron metals from waste stream or even liquids. They are vastly employed in mixer-wagons. 

Their magnetic field is made with permanent magnets therefore they do not require any power supply to operate.

Magnetic tubes are a cheap solution that ensures optimal iron tramp removal.

The magnetic tubes are normally positioned parallelly at a set distance from one another. This distance depends on the diameter of the tube and the size of the waste material from which iron has to be removed. 

Grate magnets can be fitted in hoppers or inside pipes and they are used to attract the Fe tramp metal.

There are mechanical, chemical, physical and thermal limits to the use of magnetic tubes and grate magnets:

• Mechanical limits:the magnetic tubes mechanical resistance depends on their diameter and length. The designer must consider the 304 steel tube as the resistant element; 

• Chemical limits: the tube is in 304 stainless steel (UNIX8CN1910), therefore the materials that come in contact with it – powder or gas – must be compatible with this kind of steel;

• Physical limits: the contact induction values of the magnets inside the tube varis from 1500 Gauss to 1.2 Tesla (1 T = 10.000 G). 1500 Gauss attract Fe material measuring over 0.8mm., while 1.2 Tesla attract both trump iron and paramagnetic material. However, the most used magnets measure from 3000 to 6000 Gauss. 

• Thermal limits:the permanent magnets inside the tubes must work at a temperature ranging from -30°C to +80°C. Indeed, lower or higher temperatures may damage them.

Grate magnets must be periodically cleaned to ensure optimal performance.

The operator should manually remove the Ferrous material attached to the magnet surface and then replace the tube in its exact position.