Operating Manual SIGMA 2-16PK
page 41 of 77
05/2007
5.3.4.1 Precooling
Depending on the substances to be centrifuged, it may make sense to precool
the centrifuge. The precooling prevents the cooled samples in the uncooled
centrifuge from heating up to an inadmissible temperature.
•
Select the desired temperature.
•
Select a speed of 5000 rpm.
•
Close the lid. The refrigeration unit will start immediately.
•
Start the centrifuge by pressing the start button.
)
Attention!
The temperature value indicates the air temperature in the rotor chamber. Please
bear in mind that the rotor – depending on its type – will reach this temperature
only after a corresponding precooling time.
•
Open the lid in order to insert the samples. The refrigeration unit will stop so
that no white frost can form inside the rotor chamber.
Precooling at a standstill
Unmoved air in the centrifuge chamber distorts the measuring and control
behavior and causes the compressor to freeze overs. At temperatures below
0°C, aqueous liquids will freeze, making sedimentation impossible.
•
Ensure that the rotor temperature will not fall below 0 °C if it is at a standstill!
If the system is precooled at a standstill, the mechanical parts will be stressed to
a higher degree. This is why we recommend precooling the system at medium
speed (as described above).
