Metrohm 872 Extension Module Liquid handling - Manual (Page 18)

3.4 Peristaltic pump and injection valve
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872 Extension Module – Liquid handling
3.4 Peristaltic pump and injection valve
The peristaltic pump and the injection valve are utilized for the precise
measurement of small volumes.
The liquid to be dosed, e.g. sample (7-1), is pumped with the peristaltic
pump (7-2) through the sample loop (7-4) on the injection valve (7-3).
The desired volume is defined precisely by the size of the selected sample
loop.
1
2
3
4
5 6
9
10
7
8
1 2
3
4
Figure 7 Measuring volume – Filling the sample loop
1 Sample 2 Peristaltic pump
3 Injection valve 4 Sample loop
Following the switchover of the valve (8-2), the measured sample seg-
ment (8-5) is conveyed by aspiration with the Dosino (8-1) through the
10-port valve (8-4) into the transfer tubing (8-6), from where it can be
conveyed onward to a different outlet.