Siemens MicroSAM, Operating Instructions Manual, Page: 115 / 138

MicroSAM
Operating Instructions, 06/2012, C79000-G5376-C560-07
113
Appendix
A
A.1 Principle of live column switching
Two columns are connected in sequence with the live T-piece in between. The columns
have different separating properties, for example. The three operating states of the live
switching are selected by changing the pressure in the gas lines of the live T-piece:
● Straight
● Backflushing
● Cut.
To achieve this, the electronic pressure controllers are programmed at the factory using a
time function.
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The components pass through the two
columns in succession.
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Once some of the components have
passed through the first column, the flow
direction in it is reversed. The components
still present in the first column are returned
to the beginning of it, and flushed into the
atmosphere via the backflushing output.
This means that the analysis cycle can be
drastically shortened: for example, if the
components are only transported slowly
through the first column, those of higher
boiling point need not be heated up, which
is time-consuming.