By Mikel Agirregabiria – Technical Manager, ULMA-Spain; and Rajesh Shah, P. Eng, FEC – Sales Director, ULMA-Canada
In potash mining, conveyor belts are pushed to perform every single day. Underground operations battle fine, persistent, and highly abrasive dust that works its way into every gap and component. On the surface, conveyors face a different test: winter temperatures that can plunge to –40°C. And in some scenarios, belts receive freshly processed, high-temperature material only minutes after it leaves the plant.
The above radically different scenarios are with one shared challenge: keeping the belt running safely and consistently, so production never stops. In the balance between harsh conditions and operational reliability, rollers become a critical component.
The Sealing System: How a roller is shielded in harsh environments
The sealing system is the first line of defence to extend the roller’s service life and ensure optimal performance. Its mission: prevent dust and moisture from entering the bearing, which could otherwise compromise the roller’s durability.
To achieve this, there are two key principles:
- A multi-layer sealing structure designed to act in sequence.
- Avoiding oversizing the system to minimize the distance between the bearing and the roller’s point of support, reducing the risk of shaft deflection.
System architecture
ULMA’s patented sealing system is composed of four protective barriers designed to work together:
- First labyrinth: The scoop-shaped geometry of the metal cap expels water and dust outward, preventing it from accumulating – and freezing, if there is water – even when the roller is idle.
- Sealing lip: Operates while the roller is rotating, blocking the ingress of particles. Being vulcanized to the metal structure ensures long-term fixation.
- Grease chamber: Captures any particles that make it past the previous barriers.
- Second labyrinth: Uses rotation to generate centrifugal force, pushing out any particles that reach this stage.
Components: Engineered to minimize shaft deflection and maximize roller service life
Beyond these four barriers, there’s another crucial factor to optimize the sealing system: minimizing bearing depth. This distance—from the bearing to the roller’s support point—determines how much of the shaft remains cantilevered beyond the main load-bearing area.
The longer this distance, the greater the shaft deflection under radial and axial load. This deflection creates misalignment in the bearings. If the oscillation exceeds 10 minutes, internal friction and vibration increases, eventually undermining performance and shortening service life.
By minimizing bearing depth, we reduce shaft deflection, maintain bearing alignment, and prevent damaging oscillations. In potash mining—where operational conditions leave no room for error—this design detail is often what separates a reliable roller from one that fails prematurely.
Manufacturing quality and full traceability
The materials and components used in the rollers—as well as the control over their manufacturing process—are critical to ensuring that the expected design performance translates into real-world results.
Producing and supplying all parts from European facilities allows for full traceability of materials and processes, reducing variability and ensuring spare parts consistently meet original specifications.
The other side of reliability: Composite tubes
Just as the sealing system and bearing configuration are engineered to extend service life, the choice of tube material can make a decisive difference in potash mining environments.
ULMA developed heavy-duty composite rollers designed to resist both corrosion and abrasive wear from fine particles. In many cases, the strength of certain composite compounds equals—or even surpasses—that of metal tubes under these conditions.
Composite rollers offer a key operational advantage: lighter weight. This reduces manual handling effort, shortens replacement times, and improves safety during maintenance. In operations with limited access or high-risk environments, this factor becomes critical for the personnel involved.
Ultimately, their durability doesn’t just mean fewer replacements. It also means fewer interventions in critical areas, less exposure for maintenance staff, and greater operational stability for the line.
For more information about ULMA products, visit ulmaconveyor.com/en/.
