Kwatani’s success in developing custom vibrating screens for a range of scalping, sizing, dewatering, drain and rinse and desliming applications is built on decades of experience and practical research, according to CEO Kim Schoepflin.
“We focus on the detail of every project, so that the screen performance suits the customer’s mined product and expected output,” says Schoepflin. “This means working with all screen operating parameters like velocity, stroke, angle of stroke and deck inclination – as well as the appropriate screen media – to deliver results.”
A vital aspect of the engineering process is the testing of material in Kwatani’s laboratory, using wet or dry test screens and other equipment to outline options for the customer. This allows a differentiated approach to each category of screening required in mining and other sectors.
“Scalping is usually one of the first steps in the comminution process, which subjects screens to intense strain and wear,” she says. “We therefore design our scalping screens for high drop heights, large sizes of material and considerable throughput tonnages which can handle up to 7 000 tonnes of heavy run-of-mine material ore per hour.”
This means a very specific design and fabrication of deck beams, traverse beams and side plates, for instance, giving maximum uptime and reliability. Using its integrated engineering approach, Kwatani also designs the scalping panels in-house, so that they provide the best balance between impact resistance, durability, and economy.
The company also has an enviable track record in custom grizzly feeders – for scalping run-of-mine material varying from fine particles to one-metre lump sizes – across heavy duty applications in commodities including gold, manganese, and diamonds.
“Our feeders efficiently remove fines from ROM prior to secondary crushing, with a strong impact deck that minimises structural shock,” she says. “The configuration must suit the application, with rubber or steel options available. Grizzly bars can also be fabricated or supplied in a cast manganese option for heavy duty applications.”
Sizing is a broad category of screening, with wet or dry applications, where mines aim to achieve their required cut-off while maximising process plant efficiency, product quality and production tonnage. For wet applications, Kwatani offers static or dynamic water spray options on single, double, or triple deck configurations depending on material – with either unbalanced motors or exciter gearboxes for larger capacity applications.
“To protect screens’ deck components and side plates against wear, our options include a comprehensive selection of rubber, polyurethane and ceramic for greater durability,” says Schoepflin. “The key is to ensure high load capacity, improved wear life and lower operating cost.”
Kwatani’s desliming screens effectively remove slimes (fine particles) from larger particles in mineral processing, and Schoepflin says large multi-slope screens are a fashionable choice in this application.
“Our research and development has improved the efficiency of these multi-slope designs. We not only adjust the operating speed, but also the stroke and angle of stroke to optimise efficiency. We also align the number of slopes as well as change the angles of each slope to achieve better performance and life e,” she says. “For instance, we can design a more continuous curvature profile along the screen, with a higher number of slopes ensuring a gradual change of direction for material and optimise the material velocity to improve the overall screening performance.”
She highlights Kwatani’s ability to reduce the transfer of a screen’s dynamic force into the building structure in which it is housed. This is a significant concern in any application, but especially where the infrastructure is ageing.
“We design specialised counter frames for each custom screen, to minimise the transmission of forces into the support structure,” she says. “We have a range of screen mounting options – such as rubber buffers and torsional springs – to optimise this isolation effect.”