BUCHI Extraction System B-811 LSV - Manual (Page 22)

4 Description of function
22 B-811 Operation Manual, Version G
1
a Lower heating element activated
Fig. 4.6: Procedure of Soxhlet Standard
Soxhlet Warm
The method “Soxhlet Warm” follows a real Soxhlet extraction known from the glass apparatus. The
extraction is carried out under enhanced conditions because the Soxhlet extraction chamber is addi-
tionally heated up.
The solvent is heated up by the lower heating element and evaporated. The vapor rises up to the •
condenser. The condensed solvent flows down along the condensation tube into the extraction
chamber with the sample inside. The condensed solvent is collected in the extraction chamber
while the glass valve is closed. The sample is extracted.
The solvent level rises up to the optical sensor.
•
Each time the solvent level reaches the optical sensor, the solvent containing the extracted •
compounds is released into the beaker by opening the magnetic valve. The glass valve remains
open, until the extraction chamber is empty. One cycle is finished. After the first cycle is finished
(1
st solvent level detection at the optical sensor), additionally the upper heating element is activated
and warms up the solvent in the extraction chamber.
The number of cycles and/or time defines the length of the extraction process. If the programmed
number of cycles is reached and/or the extraction time is up, all valves are opened and the solvent is
released into the beaker. The upper heating element is turned off. Then the program switches to the
next step.
1
2
a Upper heating element activated
b Lower heating element activated
Fig. 4.7: Procedure of Soxhlet Warm