Relative Centrifugal Force (Rcf); Centrifugation Of Materials Or Mixtures Of Materials With A Density Higher Than 1.2 Kg/Dm; Emergency Release - Hettich EBA 20 S Mode D'emploi

EN
12

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:
RCF
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.
The relative centrifugal force (RCF) stands in relation to the revolutions per minute and the centrifugal
radius.
13

Centrifugation of materials or mixtures of materials with a density higher than 1.2 kg/dm

When centrifuging with maxim revolutions per minute the density of the materials or the material mixtures may not
3
exceed 1.2 kg/dm .
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:
Reduced speed (n )
red
e.g.: maximum speed RPM 4000, density 1.6 kg/dm
1.2 kg/dm³
n = x 4000
red
1.6 kg/dm³
If in doubt you should obtain clarification from the manufacturer.
14

Emergency release

The lid cannot be opened during power failure. An emergency release has to be executed by hand.
For emergency release disconnect the centrifuge from the mains.
Open the lid only during rotor standstill.
Only the plastic release pin provided may be used for emergency release.
1. Switch off the mains switch (switch position "0").
2. Insert the release pin horizontally into the hole located in the middle of the front panel, see drawing.
3. Push the release pin to the right, then up to a 45° position. Pull the lid upwards at the same time to unlock, see
drawing.
4. Remove the release pin from the hole again.
2.
24/53
2
⎛ ⎞
RPM
⎜ ⎟
= × ×
r 1,118
⎝ ⎠
1000
For more on the centrifugal radius see the chapter " Anhang/Appendix,
Rotoren und Zubehör/Rotors and accessories".
1.2
=
Greater density [kg/dm³]
3
RPM = 3464 RPM
3.
RCF
⇒ =
RPM
×
r 1,118
x maximum speed [RPM]
×
1000
3