Centrifuge Safety

1. Centrifuge Safety

2. Warning • Basically very simple • Potentially very dangerous

3. An example of an accident

4. Large aluminium rotor in Beckman L2-65B Rotor failed one hour into the run. The safety shielding of the unit did not contain all the metal fragments. The 14 mm thick sliding steel door on top of the unit buckled, allowing the steel rotor top to escape plus other metal fragments.

6. The unit itself was propelled sideways and damaged cabinets and shelving that contained over a hundred chemicals. Fragments from the accident made holes in the wall & ceiling & ruined a nearby fridge and ultra-low temperature freezer A shock wave from the accident shattered all four windows in the room and shook the wall causing shelving to collapse.

9. Centrifuges Possess a Lot of Energy • Friction with air causes heating thus faster machines need to run with a vacuum. • High speed and ultra-centrifuges also need refrigeration to preserve the samples

10. Rotor Life • Rotors are subjected to extreme forces. • Rotor life is dependent on the number of hours of spinning. • Rotor life is also dependent on the care used to preserve the integrity of the tube holders. • Therefore we must log all run parameters

11. Run parameters • Date. • Operator • Rpm (speed) required. • Run time required • Rotor type to be used

12. Speeds • Low to Medium - up to 10,000 rpm • High Speed – up to 21,000 rpm • Ultraspeed – up to 90,000 rpm or more Overspeed dial: prevents running rotor too fast

13. Low to Medium Speed • No vacuum required • May be refrigerated • Tubes (and rotors) must be well balanced.

14. High Speed • Must be refrigerated • Must be at least partially evacuated • Tubes must be very well balanced

15. Ultraspeed • Must be refrigerated • Must be evacuated • Tubes must be extremely well balanced • better than 10 mg

16. RotorTypes • Swinging Bucket • Low Speed • Ultraspeed • Need very special attention

18. Rotor Types • Angled • Angled • Vertical

20. Theory RCF = 1.12r (N)2 • RCF = relative centrifuge force (g) • r = radius in mm • (N = rpm in 1000’s) • Usually use a nomogram to calculate

21. rpm Radius (mm) g

22. Theory • Sedimentation Coefficient • A measure of the particle being sedimented. • Measured in Svedberg units S • Primarily density related but also related to size. • Clearing Factor K • A measure of the sedimenting ability of the rotor.

24. General Safety • Maximum speed • Securing rotor • Balancing rotor • Selecting correct tubes • Correct filling of tubes • (do not overfill) • Flammables

25. Bio Safety • Biocontainment • Decontamination

26. Loading • Balancing of tubes • Symmetrical arrangement • Load about the centre • No overfilled tubes

28. Load about the centre

29. Load symmetrically

30. Rotor Washing • Use mild detergent and soft brush. DO NOT SCRATCH SURFACE WITH WIRE BRUSH • Rinse with distilled water • Leave rotor inverted on towel to drain

31. Poor Rotor Housekeeping Pitting, corrosion and salt deposits shown

32. Centrifuge Maintenance • Wipe centrifuge bowl with damp cloth to remove salts and dirt • Clean & lightly grease centrifuge lid seal • Clean rotor lid and lightly grease o-ring • Check for scratches and pitting in the rotor tube holders

33. Summary • There is the potential for serious accidents with the misuse of any centrifuge • Take care in all aspects of use with particular attention to balancing of tubes and proper cleaning of the rotors • Report any damage of a rotor.

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