Category: Care & Maintenance 
Topic: Preventative Maintenance
Article Title: Lubrication of Rotor trunnions

The rotor trunnions are small steel knobs located at the end of a swing-out rotor. The centrifuge buckets hang from these trunnions during centrifugation. As the buckets swing on these trunnions, friction can build quickly due to the centrifugal forces.

This friction may stop the buckets from swinging out to a full 90 degrees. As a result this can cause vibrations and possibly imbalance errors. Also, friction could cause a bucket to “chatter” or not return smoothly to the vertical position during spin-down, possibly resulting in a slight remixing or degradation of results.

 

 

To prevent this problem, simply grease the trunnions regularly with Hettich Lubricating Grease (Cat. No. 4051). This will ensure consistent swing out and swing down of the centrifuge buckets.

 

The amount of grease to apply is a thin coating on the shiny surface that comes in contact with the bucket grooves. If you put on too much, a small ring of grease will spin off onto the chamber wall of the centrifuge. This cleans up easily and does not harm the centrifuge.

 

Over time, if the centrifuge appears to have a dingy or grimy look to it, this could be a sign that not enough grease is being used. The dingy look comes from the tiny metal particles that result from not enough grease and the resulting friction.

 

Lubrication of any centrifuge should be a regular activity of the laboratory. It should be done more often than the validation intervals performed by the bio medical engineers. Regular cleaning, inspection, and lubrication of a centrifuge will consistently yield the best results.