Don’t generalise about the advantages and disadvantages of different vibrating screen technologies, advises Kwatani CEO Kim Schoepflin; the key consideration is the application.
“When a customer considers their options for a screening machine, there are a number of good technologies from which to choose,” Schoepflin says. “The appropriate technology choice will depend on the application, and we believe there is a space for every technology.”
Brute force screening is the most common technology employed among mining screens. Its benefits include being generally cost effective, relatively simple to maintain and economic in terms of life cycle costs, all of which translate into lower Total Cost of Ownership (TCO).
“Having the mechanical and metallurgical knowledge in-house, Kwatani can provide the technology that best suits the application,” she says. “We are not tied to one technology, and our primary focus is on understanding exactly what the customer needs, and providing a solution that is engineered for tonnage.”
Twin-mass or resonant screens, which run very close to a natural frequency, have a self-amplification benefit, says Kenny Mayhew-Ridgers, Kwatani’s chief operating officer.
“This gives the screen a greater energy-efficiency,” he says. “There are, however, limits on the size of these units. In addition, maintenance is more costly as springs or rubbers must be changed regularly or the efficiency benefit is lost.”
He notes that twin-mass screens also tend to be heavier. This can cause confusion when presenting technology comparisons to customers.
“Often the overall mass of the twin-mass screen is compared with the mass of the brute force screen, and this is obviously not correct,” he says. “Rather, it is the deck sizes that must be compared, as this is the element that does the work.”
While the mechanics that drive the screening process is different, the motion of the panel is what is important. This is where interaction occurs between the particles and the screen panels.
The efficiency of the process then depends on the screen’s speed, frequency, drive angle and movement of the panel relative to the particles.
While some proponents will generalise about common challenges with brute force screens, Mayhew-Ridgers notes that these observations are seldom valid. Various manufacturers offer a range of brute force technology solutions, each with its own benefits.
Schoepflin highlights that Kwatani works to raise awareness in the industry about what each technology is about. This makes it easier for users to make informed decisions about the technologies they choose.
She also says it is important for users to be confident that their chosen screen is well supported by local experts. “It is vital for OEMs to prioritise the customer’s application when considering the basic screen technology and design,” she concludes.
“While optimising screen panels to achieve higher screening efficiency is always an option, it is not the silver bullet.”