| CALCULATING:
The performance of a centrifuge is often specified as the maximum rotor speed. However, the speed provides only an approximation of the force actually acting on the centrifuged material and causing the mixtures to be separated. This force is termed the relative centrifugal force (RCF). The non-unit-specific numerical value indicates the multiple by which the centrifugal force exceeds the acceleration due to gravity ‘g’.
The formula for calculating RCF is:
RCF = (n/1000)2 x r x 11 ,18
n = revolutions per minute (RPM)
r = radius in cm
This means that a doubling of the radius results in a doubling of the RCF; a doubling of the speed results in a quadrupling of the RCF. Consequently, the performance of centrifuges can only be compared by way of the RCF figure.
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