Agilent Technologies 1260 Infinity VL User Manual page 12

1
Introduction
Overview of the Hydraulic Path
Hydraulic Path
Figure 2
How Does the Pump Work?
In the quaternary pump, the liquid runs from the solvent reservoir through the
degasser to the MCGV and from there to the inlet valve.
The pump assembly comprises two substantially identical piston/chamber
units. Both piston/chamber units comprise a ball-screw drive and a pump
head with one sapphire piston for reciprocating movement in it.
A servo-controlled variable reluctance motor drives the two ball screw drives
in opposite directions. The gears for the ball-screw drives have different
circumferences (ratio 2:1) allowing the first piston to move at twice the speed
of the second piston. The solvent enters the pump head close to the bottom
limit and leaves it at its top. The outer diameter of the piston is smaller than
12
Hydraulic Path of the Quaternary Pump
1260 Infinity QuatPump VL User Manual