Bio-Rad ChromLab™ Software - Manual (Page 52)

2 | The NGC Instrument
50 | NGC Chromatography Systems and ChromLab Software
How the Inlet Valves Work
The function of an inlet valve is determined by the type of pump to which it is
connected to. Inlet valves connected to the system pumps are used for buffers and
are referred to as buffer inlet valves. Inlet valves connected to the sample pump are
used for samples and are referred to as sample inlet valves.
Buffer Inlet Valve
The NGC systems support the use of up to two buffer inlet valves. Systems with
buffer inlet valves that also include a buffer blending valve
require two buffer inlet
valves. This enables the system to switch between buffer blending and simple
gradients without replumbing. In this configuration, the buffer inlet valves are
located between the buffer blending valve and the system pumps. The buffer
blending valve connects to the inlet valves through port 8/BB on each valve. The
outlet of each inlet valve flows to system pumps A and B. The seven ports on each
buffer inlet valve can be connected to buffers that can be used to create simple salt
gradients.
In the absence of the buffer blending valve, eight buffers can be connected to the
inlet port of each system pump.
Sample Inlet Valve
The NGC system supports the use of up to two daisy-chained sample inlet valves.
The sample inlet valve is connected to the inlet port of the sample pump to serve as
an autosampler for a small number of samples. This configuration is ideal for
automated processing of multiple large-volume samples. When two sample inlet
valves are used, the first sample inlet valve, S1, is connected directly to the sample
pump. The second valve, S2, is connected to port 8 on S1. In this configuration, the
system can switch between up to seven samples on S1 and eight different samples
on S2 for a total of up to 15 samples.
Tip: Port 8 on S2 in the daisy-chain configuration (or on S1 if using a single
sample inlet valve) is the default port for buffer solution required to wash out the
valve and pump between sample injections.