Hettich 4050674010009QG, Operating Manual

Page: 31 / 38

EN
AB1203EN_SA Rev. 02 / 11.2022 31/38
21 Relative centrifugal force (RCF)
The relative centrifugal force (RCF) is given as a multiple of the acceleration of gravity (g). It is a unit-free value and
serves to compare the separation and sedimentation performance.
These values are calculated using the formula below:
1,118 r
2
1000
RPM
RCF
  







1000
1,118 r
RCF
RPM



RCF = relative centrifugal force
RPM = rotational speed (revolutions per minute)
r = centrifugal radius in mm = distance from the centre of the turning axis to the bottom of the centrifuge
container. For more on the centrifugal radius see the chapter
“Anhang/Appendix,Rotoren und Zubehör/Rotors and accessories”.
The relative centrifugal force (RCF) stands in relation to the revolutions per minute and the centrifugal
radius.
22 Centrifugation of materials or mixtures of materials with a density higher than 1.2 kg/dm
3
When centrifuging with maxim revolutions per minute the density of the materials or the material mixtures may not
exceed 1.2 kg/dm
3
.
The speed must be reduced for materials or mixtures of materials with a higher density.
The permissible speed can be calculated using the following formula:
[RPM] speed maximum x
[kg/dm³] density Greater
1.2
= ) (n speed Reduced
red
e.g.: maximum speed RPM 4000, density 1.6 kg/dm
3
RPM 3464 = RPM 4000 x
kg/dm³ 1.6
kg/dm³ 1.2
= n
red
If in doubt you should obtain clarification from the manufacturer.
23 Emergency unlocking
In the event of a power failure, the lid cannot be unlocked with the motor. Emergency unlocking must be done by
hand.
To unlock in an emergency, disconnect the centrifuge from the mains.
Open the lid only when the rotor is at a standstill.
CAUTION! Damage to the lock during emergency unlocking by turning the hexagon Allen key in clockwise
direction (to the right).
The Allen key may only be turned counter clockwise (to the left); see figure.
A

Switch off the mains switch (switch setting "0").

Look through the window in the lid to make sure that the rotor is at a
standstill.

Insert the Allen key horizontally in the bore (A) and turn carefully counter
clockwise (to the left) until the lid opens.

Pull the Allen key back out of the bore.