Agilent Technologies 1100 series Reference Manual page 209

Introduction to the Binary Pump
Introduction to the Binary Pump
How Does Variable Stroke Volume Work?
Due to the compression of the pump-chamber volume each piston stroke of
the pump will generate a small pressure pulsation, influencing the flow ripple
of the pump. The amplitude of the pressure pulsation is mainly dependent on
the stroke volume and the compressibility compensation for the solvent in
use. Small stroke volumes will generate less pressure pulsations than higher
stroke volumes at same flow rates. In addition the frequency of the pressure
pulsations will be higher. This will decrease the influence of flow pulsations
on quantitative results.
In gradient mode smaller stroke volumes resulting in less flow ripple will
improve composition ripple.
The binary pump uses a processor-controlled ball screw system to drive its
pistons. The normal stroke volume is optimized for the selected flow rate.
Small flow rates use a small stroke volume while higher flow rates use a
higher stroke volume.
The stroke volume for the pump is set to AUTO mode. This means that the
stroke is optimized for the flow rate in use. A change to larger stroke volumes
is possible but not recommended.
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