Deep groove ball bearings made of plastic in pellet stoves

• What was needed: bearing for the drive mechanism, which works continuously despite the adverse environment
• Requirements: High temperature resistance, functionality despite small installation space
• xirodur® material A500
• Industry: Furniture Making / Industrial Design
• Success for the customer: Plastic ball bearings guarantee smooth running in the long term and reduce downtime.

Go to the pellet stove: The pellet stove Gravity allows the electricity-free transport of wood pellets into the combustion chamber through a mechanical drive unit. In addition to its current-free function, it is adjustable in three stages, can be stopped immediately without completely burning the pellets. With an efficiency of 80%, it is the first stove in its class to work according to this innovative system.  

Problem

Both metallic and various polymer plain bearings did not convince in tests of "Erwin Koppe - Keramische Heizgeräte GmbH". Metallic ball bearings not only seized too fast, but were too loud in operation. Alternative tests with polymer plain bearings led to excessive coefficients of friction, so that these were also discarded. The problem was to find a component that keeps the complete mechanism running despite very small installation space and is also durable, temperature-resistant and insensitive to dirt.  

Solution

Two self-lubricating plastic ball bearings with the xirodur® A500 material are used in the mechanical drive unit. They ensure that the wood pellets are fed to the combustion chamber via a roller. The biggest advantage lies in the high temperature resistance of the ball bearing material. Short-term temperatures of up to 150°C are easily possible and due to the absence of external lubricants nothing can get stuck inside the shaft. Thus, the plastic ball bearings always guarantee the required smooth running.

Used product