Metrohm 872 Extension Module Liquid handling - Manual (Page 43)

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5 Installation
872 Extension Module – Liquid handling
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The sample loop can be replaced, depending on the volume needed.
Replacing the sample loop
NOTE
Use only 6.2744.010 PEEK pressure screws for connecting capillaries
and sample loop to the injection valve.
1 Removing existing sample loop
￭ Loosen 6.2744.010 pressure screws at connector 3 and connec-
tor 6.
￭ Remove sample loop.
2 Mounting new sample loop
￭ Fasten one end of the sample loop (22-2) with a 6.2744.010
PEEK pressure screw (22-7) to connector 3.
￭ Fasten the other end of the sample loop (22-2) with a second
6.2744.010 PEEK pressure screw (22-7) to connector 6.
5.6.2 Mode of operation of the injection valve
The injection valve (22-1) can adopt two valve positions - FILL and
INJECT. Switching back and forth between the two valve positions deter-
mines whether the sample path or the transfer solution path is guided
through the sample loop. The following figure provides a schematic dis-
play of the flow paths of the two valve positions.
1 2
4 5
3 6
1 2
4 5
3 6
1 2
3
5
4 3 4
1 2
A B
Figure 23 Injection valve – Positions
A Position FILL B Position INJECT
1 Transfer solution outlet 2 Transfer solution inlet