Not only does conveyor belt slippage have negative financial implications for process plants and mines, but it is also potentially dangerous. In instances where the slippage continues, there is an increased danger of fire as well as damage to the carcass and splice, caused when the belt does not grip. To alleviate these issues, Multotec Wear Linings has developed MultoLag™, a direct bond ceramic pulley lagging system for drive and non-drive pulleys. The standard 100 mm by 25 mm by 6 mm smooth high alumina ceramic tiles are applied to non-drive pulleys while studded tile lagging is applied to drive pulleys.
MultoLag lagging serves as a maintenance free wear resistant cover which is applied to pulley shells to improve traction in the case of drive pulleys and provide a polished low friction surface on non-drive pulleys. The high co-efficient of friction, approximately 0.78, of the “studded” tiles on the drive pulleys ensures no movement between ceramic lined drive pulley surface and the conveyor belt surface. It is not possible for wear to occur if there is no movement between surfaces. Conversely, the smooth/polished surface provided by the very hard ceramic on the non-drive pulleys provides minimal friction, less resistance and therefore no wear.
“Ceramic pulley lagging would be used in instances where the pulley operates in extremely aggressive conditions. Typically this would be in wet conditions and other applications where a low co-efficient of friction or a high level of traction is required on drive pulleys or where general wear protection of the non-drive pulley is needed. This would include bucket elevators or where material cannot be prevented from becoming trapped between the pulley shell and belt,” Noel Mills of Multotec Wear Linings points out. Ceramic lined drive pulleys are covered with high-density 20 by 20 by 6 mm ceramic tiles, with 1 mm-high round-edged studs on the tile face that create maximum traction, without the associated damage to belts.
The 6 mm thick high-density smooth ceramic tiles are bonded directly to the pulley’s surface with specially formulated Multotec Hi-Bond epoxy. This allows the company to achieve a bond strength at least 70% higher than that of rubber to steel or rubber to ceramic. The epoxy allows for surface flexing, corrosion protection and water dissipation. In the unlikely event that patching is required, local damage can be repaired quickly without removing the surrounding pulley lining. “An attractive feature of the ceramic material is that, although more costly than conventional lagging, it is field proven and in one application has already been in operation for a lifespan of more than 200 months compared to a mere 8 months for the original liner,” Mills says.
Another advantage of using ceramics for pulleys includes belt take-up masses which can be reduced due to increased traction on drive pulleys, and this reduced belt tension leads to increased belt and pulley life. “Multotec’s Direct Bonded Ceramic Pulley Lagging is a cost effective solution which ensures optimum traction of drive pulleys under wet and slippery conditions. There have been many instances of substantially reduced downtime and an extended lagging lifespan for mining and minerals processing companies, where the product is installed at coal terminals, beneficiation plants, cement plants, power stations and quarries,” Mills concludes.
