When it comes to the preparation of mineral raw materials, Sandvik AB, Stockholm/Sweden is renowned for its world class crushing and screening technology. Perhaps it is less well-known that Sandvik also has an outstanding range of screening media. We can expect this to change based on the positive customer feedback Sandvik is now receiving on its new WX7000 screening media.
The operating hour monitor was reporting exactly 1.632 h of operation when Selim Sahin, Sales Manager Sandvik screening media & wear protection in central Europe, dropped by at the Bischofsheim plant of Basalt AG on 4th October 2017 to reassure himself that his promise was standing the test. Sandvik’s new WX7000 screening media had been installed in the lower deck of a screening machine at the plant in March 2017 (Figure 1). Since then, operators have been carefully monitoring this efficient, anti-blinding, tensioned screening media which is made from wear-resistant polyurethane. So far, they are seeing excellent screening results.
The decision to change to the WX7000 screening media from the previously used wire mesh media was a result of a long and close partnership with the customer. The plant underwent extensive modernization during 2011/12 and, following in-depth discussions with Sandvik, several Sandvik cone crushers (Sandvik CH660, Sandvik H440 and Sandvik H3000) have taken over preparation of the pre-crushed basalt in the post-crushing stages.
During discussions regarding the winter repair program, the customer mentioned he was frequently experiencing difficulties changing the media on the lower deck of the screening unit. Taking note of production conditions and required parameters, Sandvik WX7000 tensioned anti-blinding polyurethane screening media was suggested as the solution. Alongside the guaranteed wear life offered by the manufacturer, operators were also reassured by the professional approach of Sandvik’s experts. These two factors combined led to the decision to install the WX7000 screening media.
A specialist Sandvik screening media development team made the journey from Sweden to change the screening media on the lower deck of a 12 m2 circular vibrating screen, which had been in service for a long time. They examined the material feeding section and evaluated the existing grading analyses. After a detailed investigation, they recommended an overlapping, longitudinally tensioned version of WX7000 for the screening deck. Finally, the hole pattern was accurately defined to avoid misplaced particles and to produce a clean target granulation, with as few undersized particles as possible.
Deputy Plant Manager Burkhard Kunze was very impressed by how easy it was to install the flexible WX7000 screening mats. In the past, routine changes of the rigid wire mesh on the lower deck were arduous and physically demanding, an even greater burden due to the required frequency of the media changes. The plant stood idle for at least half a day every ten to twelve weeks due to the need to change the wire mesh. Various attempts to switch to harp or rubber had failed, due to quality and/or wear issues. The desired aim to reduce wear, prolong change cycles and maximize product quality could only be achieved with Sandvik WX7000.
Operators have stated that the considerable increase in wear life is already having a positive effect on operating costs. After a detailed analysis it has confirmed that it has already been possible to measure the direct utilization value of the process.
When inspecting the screening media after six months’ use, it showed no weaknesses, no clogging and no initial visible signs of wear. The wear-resistant polyurethane-material is designed both for fine screening and for harsh operating conditions. Integrated steel cable reinforcement minimizes both stretch and the resulting risk of out-of-control flutter, guarantees secure attachment and lengthens adjustment intervals. The polyurethane material’s flexibility prevents the holes from clogging. They are punched out in various geometrical shapes and are exactly matched to the required task.