Category: Quality & Safety
Topic: Centrifugation Safety
Article Title: Limited Service Life (Cycle Counts)

For the safety of its customers, Hettich has developed a time table for the safe use and reliability of its critical components.

The use of rotors, buckets and accessories is limited by time and/or operating cycle counts. (1 complete centrifugation run = 1 cycle) These particular parts are marked with the maximum permitted number of operating cycles, or with an expiration date and the maximum permitted number of operating cycles, or just with the expiration date; e.g.: - "einsetzbar bis Ende: ΙV. Quartal 2011 / usable until end of: ΙV. Quarter 2011" or "einsetzbar bis Ende Monat/Jahr: 10/2011 / usable until end of month/year: 10/2011" - "Max. Lauf Zyklen / max. cycles: 40000".

For safety reasons, rotors, buckets and accessory parts may no longer be used if either the indicated maximum number of operating cycles or the indicated expiration date has been reached. On newer centrifuges, the number of centrifuge operations can be queried. See the chapter on "Querying the operating hours and the number of centrifuge operations".

On older centrifuges, the number of cycles can be approximated:

# of uses per day multiplied by number of days in service

While not exact, this calculation will be able to tell you whether you need to consider replacing these critical components.