Metrohm 746 VA Trace Analyzer - Manual (Page 48)

3.4 Multi-mode electrode (MME)
746 VA Trace Analyzer / 747 VA Stand
3-21
5 Evacuating in vertical position
• Place multi-mode electrode 38 38 vertically in the electrode holder 114 114 (see
Fig. 15-1).
• Evacuate for ca. 2 min in this position.
6 Evacuating in inclined position
• Carefully tilt multi-mode electrode 38 38 in the electrode holder 114 114 to an
inclined position and continue evacuating (see Fig. 15-2).
7 Release vacuum
• As soon as mercury issues from the tip of the glass capillary 109 109 into the
filling tubing 115 115, carefully release the vacuum by opening the vacuum
release tap.
The filling tubing 115 115 must not be disconnected from the glass capil-
lary 109 109 when under vacuum, otherwise the mercury which has
issued from the capillary would be sprayed onto the tubing wall and
can no longer be disposed of in drop form!
• Tap the glass capillary 109 109 gently by hand so that any mercury drops at
its tip are knocked into the filling tubing 115 115.
• Disconnect filling tubing 115 115 with filling cone 116 116 from glass capillary
109 109.
• Place multi-mode electrode 38 38 in a horizontal position in the electrode
holder 114 114 (see Fig. 15-3).
From now on, the MME must be left in this position until it is installed in
the stand!
8 Install multi-mode electrode in 747 VA Stand
• With measuring head arm 40 40 tilted back, push empty measuring vessel
28 28 into the holder 26 26 of the 747 VA Stand and then lower measuring head
arm 40 40.
• Carefully insert multi-mode electrode 38 38 in opening 76 76 of the measuring
head 41 41 (during insertion, the tip of the capillary must not touch the
measuring head) and push in as far as it will go.
9 Connect multi-mode electrode
• Screw FEP tubing 51 51 for the inert gas supply into connection 93 93 of the
multi-mode electrode 38 38.
• Screw FEP tubing 59 59 for the inert gas supply into connection 94 94 of the
multi-mode electrode 38 38.
• Attach electrode cable 37 37 (WE) to screw connection 110 110 of the multi-
mode electrode 38 38: push cable lug under the screw and then tighten
screw firmly.