2 stages of an extraction cycle, N 6.4.2 – BUCHI SpeedExtractor E-916 User Manual
Page 52
6 Operation
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SpeedExtractor E-916/E-914 Operation Manual, Version D
The heating block is fixed on movable guide rails.
This allows the operator to push the heating block
to the back to get easy access to the cup seals (for
inspection or exchange) and to pull it out to load the
extraction cells. Proceed as follows: Push the protec-
tive shield to the top and pull out the heating block as
far as possible. Use the extraction cell gripper (P/N
053030 for E-916, P/N 053026 for E-914) to place the
cells into the heating block. Move the heating block
backward until it snaps in the middle position.
Close the protective shield for safety reasons. The lift
does not move unless the shield is closed.
NOTE
In order to achieve reproducible results, never place
the extraction cells in the heating block before the
operating temperature is reached (equilibrium).
6.4.2
Stages of an extraction cycle
Generally, every extraction method consists of a number of cycles, which can be divided into 3
phases, the heat-up, hold and discharge time. Prior the first cycle, the tightness test is carried out.
• Tightness test using nitrogen (checks, whether there is a cell in the activated position)
The tightness test is a quick initial check that verifies whether the system is closed. In the event of
open outlet valves or empty positions in the heating block, the extraction run is aborted, and error
message is displayed.
The tightness test is not the same as the leak test (section 6.2.5). The leak test scrutinizes the leak-
ing rate of each position and displays the corresponding pressures accordingly; it is not part of the
extraction method. On the other hand, the tightness test is an inherent element of each extraction
procedure and cannot be altered or modified in any way. It is essentially an internal safety proce-
dure and is therefore not accessible to the operator.
• Heat-up time (heat-up of sample, solvent and cell)
In the time period between the tightness test and hold step the pressure is increased step-by-step