Agilent Technologies InfinityLab LC Series User Manual page 24

1 Introduction
Overview of the Hydraulic Path
When turned on, the pump runs through an initialization procedure to determine
the upper dead position of the first piston. The first piston moves slowly upwards
into the mechanical stop of the pump chamber and from there it moves back for
a defined distance. The controller stores this piston position in memory. After
this initialization the pump starts operation with the set parameters. The inlet
valve opens and the down-moving piston draws solvent into the first pump
chamber. At the same time, the second piston moves upwards delivering to the
system. After a controller-defined stroke length that depends on the flow rate the
drive motor is stopped and the inlet valve closes. The motor direction is reversed
and moves the first piston up until it reaches the stored upper limit and at the
same time the second piston moves downwards. Then the sequence starts
again moving the pistons up and down between the two limits. During the up
movement of the first piston, the solvent in the pump chamber is pressed
through the outlet valve into the second pump chamber. The second piston
draws in half of the volume displaced by the first piston and the remaining half
volume is directly delivered to the system. During the drawing stroke of the first
piston, the second piston delivers the drawn volume to the system.
Quaternary pumps: For solvent compositions from the solvent bottles A, B, C, D
the controller divides the length of the intake stroke in certain fractions in which
the gradient valve connects the specified solvent channel to the pump input.
For specifications, see:
•
•
•
Agilent InfinityLab LC Series 1260 Infinity II Isocratic and Quaternary Pumps User Manual
isocratic pump: "Performance Specifications Agilent 1260 Infinity II Isocratic
Pump (G7110B)" on page 39
quaternary pumps:
• "Performance Specifications Agilent 1260 Infinity II Quaternary Pump
(G7111B)" on page 43
• "Performance Specifications Agilent 1260 Infinity II Quaternary Pump VL
(G7111A)" on page 41
Bio-inert pump: "Performance Specifications Agilent 1260 Infinity II Bio-inert
Pump (G5654A)" on page 45
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