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CPS Polyurethane Disc Rollers

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The client’s previous rollers were creating significant carryback issues, thus causing frequent maintenance and change-outs. CPS replaced the previous rollers to CPS Polyurethane (PU) disc rollers to lessen carryback issues and improve operations through its belt cleaning properties, durability, and longer life expectancy.

The Challenge

The sheer volume of ore being transported over the belt combined with the properties of the conveyed wet ROM material created significant carryback issues. Consequently, operations were having multiple unscheduled shutdowns on a weekly basis to replace failed rollers before they damaged the conveyor belt, at an enormous loss of production. The 6mm steel return rollers were lasting between 15 to 36 weeks depending on the location.

Particles that make up carryback typically have a higher moisture content than the overall conveyed material. As the belt rolls over the idlers, the belt vibrates — creating a settling action. The smallest moisture-rich fines sift to the bottom of the material bed, where they can create an adhesive mixture that clings to the conveyor belt beyond the discharge point of the head pulley.

The material fines that make it past the conveyor scrapers then become dislodged along the return run of the conveyor and build-up beneath the belt. Carryback build-up on components such as rollers reduces operating efficiency, increases maintenance costs, reduces plant safety, shortens belt life, and leads to premature roller failure.

The Solution

The CPS team recommended that the initial bank of return frames back from the head pulley were to be changed out to CPS PU disc rollers. CPS PU disc rollers tend to assist with belt cleaning due to the flex of the belt over the roller rings and assist in belt training as the largest areas of belt contact occur at the roller edges, guiding the belt into the centre.

Furthermore, the ringed rollers could improve performance on tracking frames by providing an increased coefficient of friction between roller and belt compared to rubber or steel. Ringed rollers assist with maintenance requirements by providing a visual wear indicator for replacement as the wear of the rings is clearly visible during inspections.

The CPS PU ringed rollers survived well past the existing steel roller life with absolute minimal wear measured, and have been in service for over two years and are still running today.

The initial trial/test data was measured during shutdowns on a primarily crushed ore overland belt. Wear data was collected across the face of the roller at the three-ring locations over several incremental measurement dates.

Generally, polyurethane ringed rollers are less expensive than equivalent rubber lagged rollers installed in common high-wear locations, though are more expensive than steel rollers. Based on the trial data and further installations of CPS PU ringed rollers, the overall Life Cycle Cost (LCC) has considerably dropped to approximately 30 percent of the LCC of steel rollers due to the significant life increase brought by CPS PU ringed rollers. CPS PU ringed rollers also come in a variety of ring styles based on client requirements and failure mode drivers.