Siemens MicroSAM Operating Instructions Manual page 118

Glossary
A thought experiment
116
The pressure P2 from the previous figure is
read on the y-axis. This pressure P2 is then
applied between the two columns. The input
of the first column is left open. This results in
a pressure distribution with the flows as
shown on the left.
Conclusion:
the first column is now operated in
backflushing mode.
Operating Instructions, 06/2012, C79000-G5376-C560-07
MicroSAM