Metrohm 812 Valve Unit - Manual (Page 13)

2 Installation
812 Valve Unit
10
2.4 Connections at injection valve
2.4.1 General information
The two six-way valves at the 812 Valve Unit each have 6 connections
for capillaries which are switched as follows:
Fill
1 2
3 6
4 5
Inject
1 2
3 6
4 5
Fig. 4: Switching of injection valves
Connections 1 and 2 of the valve are normally used for supply of sam-
ple solution, connections 4 and 5 for eluent supply, and connections 3
and 6 for sample loop installation. For solution supply in the low pres-
sure range (sample feed by use of a syringe or a peristaltic pump), the
6.1803.020 PTFE capillary (i.d. 0.97 mm) is used; in the high pressure
range, the 6.1831.010 PEEK capillary (i.d. 0.25 mm) is used. For both
capillaries, a 6.2744.010 PEEK compression fitting is used as connec-
tor.
2.4.2 Attaching standard accessories
The standard accessories supplied with the 812 Valve Unit can be used
to equip one valve for manual filling of the sample loop. Proceed as fol-
lows (see Fig. 5):
1 Connecting the syringe
• Cut off a piece of the 6.1803.020 PTFE capillary to the de-
sired length (at best using the optionally available 6.2621.080
tubing cutter) and fit it on both sides with a 6.2744.010 PEEK
compression fitting (do not tighten too firmly).
• Screw one end of the PTFE capillary 13 to connection 1 of
the injection valve.
• Screw the other end of the PTFE capillary 13 to the
6.2744.120 coupling.
• Push 6.2816.020 syringe (without needle) as far as it will go
into the connection of the 6.2744.120 coupling.