14 1260 Infinity QuatPump VL User Manual
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 passive 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
passive 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.
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 of the quaternary pump, see “Performance
Specifications” on page 24.
Tabl e 1 Materials in contact with mobile phase
MCGV SST, PTFE
Pump head SST, gold, sapphire, ceramic
Passive inlet valve SST, gold, sapphire, ruby, ceramic, PTFE
Outlet valve SST, gold, sapphire, ruby
Adapter SST, gold
Purge valve SST, gold, PTFE, ceramic, PEEK
Damping unit Gold, SST
Degasser chamber TFE/PDD Copolymer, FEP, PEEK, PPS
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