SmartScreen technology - Ultrafine wet screening enhances sub-millimeter particle separation
Bateman Engineering and Smart Screen Systems Inc. of Minnesota, USA are now marketing Smart Screen's patented screening system to mineral processors in the African and Australian markets, as well as into Bateman Engineering projects globally.
This innovative system permits the screening of fine particulate material with lower energy consumption, noise generation and maintenance cost than is possible with conventional systems.
Generally, large screen motions are required for the separation of particles of different sizes. In SmartScreens the screening surface is suspended on set springs designed to resonate at the desired operating frequency with an optimal balance of motion parallel and perpendicular to material flow. Because the side plates that support the drive assembly in a conventional screen have been eliminated, the weight of the screen panel is minimised so that only relatively low vibratory forces are needed for the screening motion.
Energy-saving electromagnetic motors and specially designed resonators to amplify the motion cause the screen panel to vibrate. The resonance desired for effective separation is maintained by a controller, accelerometer and feedback loop, which account for variations in the material load on the screen.
The SmartScreen design imparts many advantages. The driving force is minimised by keeping the screen at near resonance - it theoretically would approach zero at full resonance. Also, by tuning the springs supporting the screen panel, energy usage by the machine is maximised. Field experience shows that the power consumed during conventional screening is reduced by between 50 % and 70 % when using SmartScreens.
The total energy saving, projected over the entire processing circuit, was estimated at 5 %. Process control and efficiency of separation is also better than is possible with either hydro-cyclones or conventional screening systems, which increases the productivity and the quality of the concentrate. For example, an efficiency of more than 85 % was obtained when separating the iron fines with a cut size of 70 m microns in a feed from a secondary ball mill at a concentrator.
The elimination of the side plates on the screen panel means the footprint of a SmartScreen is not much larger than the screening area, providing high screening capacity per machine footprint.
SmartScreen has no bearings, bushes, shafts or other moving parts, meaning minimal maintenance and no lubrication. The light-weight construction also means that a screen panel can be replaced in a matter of minutes and that any motor, should it need attention, can easily be attended to. SmartScreen has an electronic test facility in the control panel to permit regular maintenance checks.
The screens were first used in taconite concentrators to screen fine iron-ore concentrate, one of the most difficult materials to screen effectively. Nearly 50 are already being used for this purpose to obtain cut sizes between 70 m microns and 124 m microns, with a further eight being used to process a vanadium mineral with a cut size of 150m microns.
Tests are underway on material outside of this range. Besides minerals processing, it is anticipated that SmartScreen Systems will also have wide application in the food and agriculture industries.
