The Misconception of Eddy Current Separator Belt Length

3rd of 5 Misconceptions About Eddy Current Separators

Eddy Current Separators are used extensively in the recycling industry to separate non-ferrous metal (e.g. aluminium beverage cans, shredded aluminium and copper etc) from non-metallic materials.  However, there are various misconceptions as to what helps and hinders separation and this blog investigates the length of the conveyor belt.

The conveyor belt needs to be long

The length of the conveyor belt of an Eddy Current Separator ranges considerably and there are claims that longer belts improve the level of separation.  But is this true?

Firstly, it is important to consider the reason for the belt in the design of an Eddy Current Separator.  The belt is simply a way to transport the material into the rotating magnetic field or ‘separation zone’.  As discussed in the 2nd of the ‘misconceptions’ series, the belt speed can vary considerably, but why would the belt need to be long?

For optimum separation, the material needs to be settled on the conveyor belt before entering the ‘separation zone’ and this is one of the reasons given for a long belt.  However, the best level of separation is achieved when the material being fed onto the conveyor belt is via a Vibratory Feeder.  The Vibratory Feeder evenly spreads the material, preferably into a mono layer, before it drops onto the conveyor belt.  As the flow of the material is controlled by the vibration of the Vibratory Feeder and the end of the Feeder tray is close to the surface of the belt, the material settles down quickly and hence a shorter conveyor belt can be used.

Bunting_Metal_Separation_Module_Recapture_Plastics-7547

For some applications, direct feed of the material from a Vibratory Feeder with a non-metallic tray or tray tip, into the ‘separation zone’ may even negate the need for the conveyor belt at all.  However, the conveyor belt in this case would work as a cleaning device, taking any magnetic material away out of the product and away from the shell of the Eddy Current Separator rotor.

In conclusion, the length of the Eddy Current Separator belt depends on how the material is being fed and:

  • If being fed straight from a conveyor, have a long belt;
  • If being fed via a Vibratory Feeder, have a shorter belt;

Previous blogs looking at the misconceptions of Eddy Current Separators include:

Bunting provide a range of metal separation solutions for the recycling industry.  For further details on the Bunting range of Eddy Current Separators, Magnetic Separators and Metal Detectors please contact Carlton Hicks (carltonhicks@buntingeurope.com) or our technical sales team on:

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s