Fisher Scientific accuSpin 3, Operating Instructions Manual

Page: 36 / 82

Operation
32
Because of the higher difference of the
radii (r
max
- r
min
) the pressure of liquid column to the
tube bottom is appreciably higher and strongly de-
pended on filling.
Plastic tubes and bottles – especially for the highest
load (speed, temperature) – have a limited life time
only and must to be replaced as recommended by the
manufacturer.
Maximum permissible load difference
The smaller the imbalance of the centrifuge,
the better the separation effect, because as
imbalance is minimized, so is the resultant
vibration that could affect separation quality.
Therefore it is important, that the tubes are balanced
properly.
The maximum permissible load difference depends on
several factors (e.g. rotor, loading). For a swinging
bucket rotor 7500 4393 this amounts to at least 20 g in
opposite carriers.
The values refer to a weight difference on the bottom of
the tube. If there is a weight difference resulting from
inhomogeneously filled tubes, the centrifuge can oper-
ate with larger weight differences as well, without caus-
ing an imbalance interruption.
Inserting the centrifuge tubes
The rotor must be loaded symmetri-
cally. Failure to do so can cause rotor
imbalance, which may lead to noisy
operation, affect separation quality, or
result in imbalance detection shut-
down, as well as introduce significant
detrimental wear to the motor and
drive system.
The rotor has to be loaded symmetrically. When load-
ing the rotor only partially, you have to ensure that
opposite bores always receive tubes of equal weight
(when centrifuging a single sample, place a centrifuge
tube e.g. filled with water).
After placing the tubes, install the rotor cover.