Metrohm 850 Professional IC Cation - Gradient - Manual (Page 50)

3.14 Injection valve
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850 Professional IC Cation – HP-Gradient
Replacing the sample loop
The sample loop can be replaced, depending on requirements. For addi-
tional information concerning selection of the appropriate sample loop,
see Chapter 3.14.3, page 43.
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 (23-2) with a 6.2744.010
PEEK pressure screw (23-7) to connector 3.
￭ Fasten the other end of the sample loop (23-2) with a second
6.2744.010 PEEK pressure screw (23-7) to connector 6.
3.14.2 Mode of operation of the injection valve
The injection valve (see Figure 24, page 42) can adopt two valve posi-
tions - FILL and INJECT. Switching back and forth between the two valve
positions determines whether the sample path or the eluent path is gui-
ded through the sample loop. The following figure provides a schematic
display of the flow paths of the two valve positions.
1 2
4 5
3 6
1 2
4 5
3 6
1 2
4 3
5
4 3
1 2
A B
Figure 24 Injection valve – Positions
A Position FILL B Position INJECT