BUCHI SpeedExtractor E-916 - Manual (Page 25)

4 Description of function
25 SpeedExtractor E-916/E-914 Operation Manual, Version D
4.3 Overview of the extraction process
A complete extraction process involves the following phases:
Phase 1: Preparation
• Creating an extraction method (see section 6.2.3).
• Preparing the instrument for operation. This involves filling the solvent reservoirs and preheating
the instrument to the temperature of operation (equilibration), see section 6.2.3.
• Packing the extraction cell with the sample (see section 6.2.3).
• Placing the collection vials in the collection tray (see section 6.4.1).
• Placing the extraction cell into the preheated heating block (see section 6.4.1).
Phase 2: Extraction cycles
• Start extraction method (see section 6.4.8).
An extraction cycle involves three steps with a user-defined time period (except for HEAT UP):
In a first HEAT UP step the pressure and temperature inside the extraction cell is slowly increased to
the set parameters of extraction program.
During HOLD step these parameters remain constant. This corresponds with the literal extraction step
at constant temperatures and pressures. After this step the outlet valve opens and the liquid extract
is DISCHARGEd and collected in collection vials or a waste bottle by means of pressure compensa-
tion. All three steps are repeated several times according to the extraction program. A complete run
may consist of 1 – 10 extraction cycles. The presence of extraction cells is checked in the TIGHTNESS
TEST at the beginning of each extraction process.
The HEAT UP step is not accessible by the user but is determined by the instrument software. The
absolute time of this period depends on the temperature, pressure, size of the extraction cell and type
of sample. Additional time is needed to fill the extraction cell. The HOLD and the DISCHARGE time
can be defined by the user individually for each cycle.
The actual time used for a complete process is shown in the STATUS menu and/or recorded by
SpeedExtractor Record software, where it can be exported to a report and printed out.
Phase 3: Flushing the lines and unloading the heating block
• Flushing the lines with fresh solvent and collecting the liquid in the collection vials (see section 6.4.2).
• Flushing with nitrogen to remove residual solvent (see section 6.4.2).
• Unloading the heating block (see section 6.4.9).
NOTE
Preheating the instrument to the temperature of operation prior to loading it with the extraction