Bio-Rad ChromLab™ Software - Manual (Page 57)

Valves
Instrument Guide | 55
Column Switching Valve
The NGC system supports up to three column switching valves. Each column
switching valve is used to connect up to five columns simultaneously, supporting up
to 15 columns. This enables automated column scouting, and the use of different
columns without connecting and disconnecting the columns. The valve includes an
internal bypass mode, which enables buffers to bypass the connected columns
when necessary (for example, when priming or cleaning the system). The valve can
also reverse the flow, which is optimal for certain separations where elution in a
narrow band is necessary. Reverse flow is also useful when cleaning a column.
The column switching valve has one inlet port, one outlet port, and five pairs of
column connection ports. In ChromLab you can program the method to
automatically change the position of the valve. The active ports are identified by
LEDs.
The column switching valve has two internal pressure sensors. ChromLab displays
the precolumn and delta pressure values. The pressure values are viewed as traces
on the chromatogram. When two or three column switching valves are present, the
NGC system monitors the delta pressure from all columns that are inline.
Overpressure events are triggered when any of the delta pressures reaches its
maximum specified limit.