CONTROLLED COPY
Centre for Biological Engineering
Standard Operating Procedure
SOP122
Title: Use and Maintenance of Sigma Refrigerated Centrifuge 3-16PK
Location:
CBE Laboratory Unit (H21/22)
Version 003
Effective Date: 26
th
June 2018
Review 26
th
June 2020
Written by: Victoria Workman
Reviewed by: P.Hourd
Approved by: R/I.Temple
Page 20 of 22
7. Over speeding because de rated over speed disc not fitted.
8. Running badly corroded and weakened rotors or buckets; stress corrosion failure.
9. Loose lid on angle rotor.
10. Incorrect installation of rotor on drive shaft.
Bench Centrifuges
Although the kinetic energy attained by the components of bench centrifuges is lower than that involved in
larger models their improper use can lead to dangerous failures.
Breakages of glass tubes or improper balancing can cause considerable vibration and 'wandering' of an
unfixed centrifuge over the bench top. This may, in extreme cases, allow the mains cable to become
wrapped around the centrifuge body with consequent strain and damage to the cable. The centrifuge may
move completely off the bench-top to the floor. This may cause the chamber lid to open and the spinning
rotor or buckets to be ejected at high speed.
A visual check should always be made to see that all tubes are filled to the same level and are not overfilled,
that glass tubes are not cracked, and that a cushion is installed in each bucket.
Centrifuging Hazardous Materials
Hazardous materials must be centrifuged in the proper type of sealed container. The basic principle of safe
containment is an air-tight, leak proof seal.
Most equipment is unsafe for the centrifuging of flammable materials. A sealed chamber is required and the
necessary design features are laid down in BS 4402 which allows only approved centrifuges to be marked
with 'Sc' (sealed chamber).
Advice on sealed containers for centrifuging hazardous chemicals is given in BS 4402 and in the book by
Price. These also mention biologically hazardous materials and these are dealt with in greater detail in
Laboratory-Acquired Infections, C.H. Collins, Butterworths, Second Edition, 1988.
If pathogenic materials are used it may be necessary to sterilise parts of a centrifuge and its accessories.
Price gives the following relevant advice. Before sterilising
always
remove and dissemble tube cap
assemblies. Tubes and bottles for autoclaving should be separated from cap parts to avoid damage and
deformation. Cellulose tubes
cannot
be autoclaved and they may explode if autoclaving is attempted.
Polyallomer tubes distort.
Polycarbonate containers with join seams should
not
be autoclaved and this method of sterilisation is
possible only for seamless polycarbonate containers. Even then severe distortion will probably render the
container useless. Cold sterilisation is recommended.
Cold methods of sterilisation that can be used on container materials include ultra violet radiation, zephiran
chloride, ethylene oxide gas and 70% ethanol (
except
cellulose)
