Thermo Scientific Dionex AS-DV, Руководство оператора

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2 • Description
Doc. 065259-05 10/12
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2.2 Dionex AS-DV Operating Principles
2.2.1 Sampling Operating Principles
The sampling head tower (see Figure 2-1 ) consists of a motor-driven
needle, with a sampling tip on the end, that moves down to engage the top
of the vial cap.
As the needle moves downward, the cap is gradually pushed into the vial
(see
Figure 2-7 ), forcing the liquid through the filter (if present) and into
the sample out line. The moving cap acts as a piston to force the liquid
from the vial. This allows samples to be loaded without the use of an
external sampling pump. The concave bottom of the vial cap traps air, so
that it can be expelled with any excess sample above the fill line. In
addition, the shape exactly matches the convex bottom of the sample vial;
when the cap is pushed completely into the vial, virtually all of the sample
is expelled.
The socket for the sampling tip is identical on both sizes of caps to allow
mating with the tip of the sampler head. The sampling head speed
(delivery speed) is set in Chromeleon (see
Section 3.5 ).
Figure 2-7. PolyVial, Cap, and Sampling Tip Features
Sampling Tip
Sample
Cap
20 m Filter (Optional)
P
Trapped Air and Excess Sample
(Expelled before sample delivery
if Bleed is enabled)
Convex vial bottom mates
with concave cap to ensure
delivery of sample complete
Sample Out Line
Fill Line
Needle