CentrifugeCentrifuge

SafetySafety

Warning

Basically very simpleBasically very simple

Potentially very dangerousPotentially very dangerous

An example of an accident

Large aluminium rotor in Beckman L2-65B Large aluminium rotor in Beckman L2-65B

Rotor failed one hour into the run.Rotor failed one hour into the run.

The safety shielding of the unit did not The safety shielding of the unit did not contain all the metal fragments.contain all the metal fragments.

The 14 mm thick sliding steel door on top The 14 mm thick sliding steel door on top of the unit buckled, allowing the steel rotor of the unit buckled, allowing the steel rotor top to escape plus other metal fragments.top to escape plus other metal fragments.

The unit itself was propelled sideways and The unit itself was propelled sideways and damaged cabinets and shelving that damaged cabinets and shelving that contained over a hundred chemicals.contained over a hundred chemicals.

Fragments from the accident made holes in Fragments from the accident made holes in the wall & ceiling & ruined a nearby fridge the wall & ceiling & ruined a nearby fridge and ultra-low temperature freezerand ultra-low temperature freezer

A shock wave from the accident shattered A shock wave from the accident shattered all four windows in the room and shook the all four windows in the room and shook the wall causing shelving to collapse.wall causing shelving to collapse.

Centrifuges Possess a Lot of Energy

Friction with air causes heating thus faster Friction with air causes heating thus faster machines need to run with a vacuum.machines need to run with a vacuum.

High speed and ultra-centrifuges also need High speed and ultra-centrifuges also need refrigeration to preserve the samplesrefrigeration to preserve the samples

Rotor Life

Rotors are subjected to extreme forces.Rotors are subjected to extreme forces.

Rotor life is dependent on the number of Rotor life is dependent on the number of hours of spinning.hours of spinning.

Rotor life is also dependent on the care used Rotor life is also dependent on the care used to preserve the integrity of the tube holders.to preserve the integrity of the tube holders.

Therefore we must log all run parametersTherefore we must log all run parameters

Run parameters

Date.Date.

OperatorOperator

Rpm (speed) required.Rpm (speed) required.

Run time requiredRun time required

Rotor type to be usedRotor type to be used

Speeds Low to MediumLow to Medium - up to 10,000 rpm - up to 10,000 rpm

High SpeedHigh Speed – up to 21,000 rpm – up to 21,000 rpm

UltraspeedUltraspeed – up to 90,000 rpm or more – up to 90,000 rpm or more

Overspeed dial: prevents running rotor too fastOverspeed dial: prevents running rotor too fast

Low to Medium Speed

No vacuum requiredNo vacuum required

May be refrigeratedMay be refrigerated

Tubes (and rotors) must be well balanced.Tubes (and rotors) must be well balanced.

High Speed

Must be refrigeratedMust be refrigerated

Must be at least partially evacuatedMust be at least partially evacuated

Tubes must be very well balancedTubes must be very well balanced

Ultraspeed

Must be refrigeratedMust be refrigerated

Must be evacuatedMust be evacuated

Tubes must be extremely well balancedTubes must be extremely well balanced better than 10 mgbetter than 10 mg

Rotor Types Swinging BucketSwinging Bucket

Low SpeedLow Speed UltraspeedUltraspeed

• Need very special attentionNeed very special attention

Rotor Types AngledAngled

AngledAngled

VerticalVertical

Theory

RCF = 1.12r (N)RCF = 1.12r (N)22

• RCF = relative centrifuge force (g)RCF = relative centrifuge force (g)

• r = radius in mmr = radius in mm

• (N = rpm in 1000’s)(N = rpm in 1000’s) Usually use a nomogram to calculateUsually use a nomogram to calculate

rpm

g

Radius (mm)

Theory

SSedimentation Coefficientedimentation Coefficient A measure of the particle being sedimented.A measure of the particle being sedimented. Measured in Svedberg units SMeasured in Svedberg units S Primarily density related but also related to size.Primarily density related but also related to size.

Clearing Factor KClearing Factor K A measure of the sedimenting ability of the rotor.A measure of the sedimenting ability of the rotor.

General Safety MaxMaximumimum speed speed Securing rotorSecuring rotor Balancing rotorBalancing rotor Selecting correct tubesSelecting correct tubes Correct filling of tubesCorrect filling of tubes

• (do not overfill)(do not overfill) FlammablesFlammables

Bio Safety

BiocontainmentBiocontainment DecontaminationDecontamination

Loading

Balancing of tubesBalancing of tubes Symmetrical arrangementSymmetrical arrangement Load about the centreLoad about the centre No overfilled tubesNo overfilled tubes

Load about the centre

Load symmetrically

Rotor Washing

Use mild detergent and soft brush. Use mild detergent and soft brush. DO NOT SCRATCH SURFACE WITH WIRE BRUSHDO NOT SCRATCH SURFACE WITH WIRE BRUSH

Rinse with distilled waterRinse with distilled water Leave rotor inverted on towel to drainLeave rotor inverted on towel to drain

Poor Rotor Housekeeping

Pitting, corrosion and salt deposits shownPitting, corrosion and salt deposits shown

Centrifuge Maintenance

Wipe centrifuge bowl with damp cloth to Wipe centrifuge bowl with damp cloth to remove salts and dirtremove salts and dirt

Clean & lightly grease centrifuge lid Clean & lightly grease centrifuge lid sealseal

Clean rotor lid and lightly grease o-ringClean rotor lid and lightly grease o-ring Check for scratches and pitting in the Check for scratches and pitting in the

rotor tube holdersrotor tube holders

Summary There is the potential for serious There is the potential for serious

accidents accidents with the misuse of any centrifugewith the misuse of any centrifuge

Take care in all aspects of use with Take care in all aspects of use with particular attention to balancing of tubes particular attention to balancing of tubes and proper cleaning of the rotorsand proper cleaning of the rotors

Report any damage of a rotor.Report any damage of a rotor.