Tech Insights · 2026-09-03
Polyurethane Belt Cleaners: Wear Study
Field data and material science show why 90–95 Shore A polyurethane blades outlast tungsten carbide in sticky, abrasive conditions — and how blade angle controls cleaning efficiency.
The problem
Carry-back is one of the costliest hidden losses on a bulk conveyor. Material that sticks to the belt after discharge falls under the return path, builds up on rollers and pulleys, and gradually misaligns the belt. The result is premature idler wear, spillage cleanup labor, and unplanned shutdowns for belt damage. The cleaner is the first line of defense, yet many plants still treat blade material as a commodity.
Material science
Polyurethane occupies a unique position between elastomer and engineering plastic. At 90–95 Shore A it offers enough elasticity to maintain edge contact across slight belt waviness, while its tear strength resists the gouging action of sharp, abrasive particles. Unlike tungsten carbide, polyurethane will not score or groove the belt cover if a fragment embeds in the blade — a critical safety margin for expensive steel-cord belts.
Field evidence
HBXM supplied polyurethane primary and secondary cleaners to a cement plant handling wet limestone/clay mix. Over 18 months, blade wear averaged 3–4 mm per quarter, versus 8–12 mm per quarter for the previous segmented carbide setup. Cleaning efficiency, measured by residual carry-back on the return side, improved from roughly 0.8 kg/m to below 0.2 kg/m.
Blade angle matters
A primary cleaner at 70–75° to the belt provides the best compromise between scraping force and blade life. Secondary cleaners work closer to 90° for final polishing. Spring or air-tensioned retainers keep the blade edge constant as it wears; rigid bolt-on mounts let the contact pressure drop within weeks, defeating the purpose of a premium material.
Bottom line
Specifying the blade material without considering tensioning and angle is half a solution. For abrasive or sticky bulk materials, a correctly tensioned 90–95 Shore A polyurethane cleaner typically delivers 3–5× the service interval of rigid alternatives and protects the belt cover at the same time.
References & Sources
- CEMA. Belt Conveyors for Bulk Materials, 7th ed. (2nd printing, 2020). Conveyor Equipment Manufacturers Association, 815 pp. ISBN 978-1891171-44-4.
- Swinderman, T., Goldbeck, L., Strebel, M., Marshall, D. & Marti, A. (eds.). Foundations™, 4th ed. (2012). The Practical Resource for Cleaner, Safer, More Productive Dust & Material Control. Martin Engineering. Free PDF.
- Metso. Conveyor Solutions Handbook, 2nd ed. (2020). Metso Outotec — covers belt cleaning, guiding, sealing and pulley-lagging systems.
- ISO 5048:1989. Continuous mechanical handling equipment — Belt conveyors with carrying idlers — Calculation of operating power and tensile forces.
- DIN 22101:2011-12. Continuous conveyors — Belt conveyors for loose bulk materials — Basis for calculation and dimensioning. DOI 10.31030/1821227.