Varian ProStar 400, Руководство по эксплуатации

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If one injection is to be made out of each sample vial, the needle
pair withdraws after the analysis time is complete and sequence
steps 1-2 starts for the next vial. If more than one injection is to
be made out of the same sample vial, the needles remain in the
vial.
Figure 5 Pressure-controlled Injection
Digital Dispenser System (DDS)
Operating Principle
The DDS is a miniature “finger pump”. The operating principle is
shown below. Fingers 1 and 3 act as inlet and outlet pinch valve,
respectively, finger 2 provides the fluid displacement. The stroke
of finger 2 is factory adjusted to provide 2 µL per stroke. Since
the volume dispensed is always a multiple of one stroke volume
(digital dispensing), i.e., 2, 4, 6 µL, etc., odd values for volumes
will be rounded down to even values.
Figure 6 Operating Principle of Digital Dispensing System (DDS)