Metrohm 757 VA Computrace - Manual (Page 32)

3 Installation
757 VA Computrace – Hardware
28
5 Evacuating in vertical position
• Place multi-mode electrode 17 vertically in the electrode holder 93 (see
Fig. 11-1).
• Evacuate for ca. 2 min in this position.
6 Evacuating in inclined position
• Carefully tilt multi-mode electrode 17 in the electrode holder 93 to an
inclined position and continue evacuating (see Fig. 11-2).
7 Release vacuum
• As soon as mercury issues from the tip of the glass capillary 88 into the
filling tubing 94, carefully release the vacuum by opening the vacuum re-
lease tap.
The filling tubing 94 must not be disconnected from the glass capillary
88 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 88 gently by hand so that any mercury drops at its
tip are knocked into the filling tubing 94.
• Disconnect filling tubing 94 with filling cone 95 from glass capillary 88.
• Place multi-mode electrode 17 in a horizontal position in the electrode
holder 93 (see Fig. 11-3).
From now on, the MME must be left in this position until it is installed in
the stand!
8 Install multi-mode electrode in 757 VA Computrace Stand
• With measuring head arm 19 tilted back, push empty measuring vessel 6
into the holder 3 of the 757 VA Computrace Stand and then lower meas-
uring head arm 19.
• Carefully insert multi-mode electrode 17 in opening 55 of the measuring
head 20 (during insertion, the tip of the capillary 88 must not touch the
measuring head) and push in as far as it will go.
9 Connect multi-mode electrode
• Screw FEP tubing 30 for the inert gas supply into connection 72 of the
multi-mode electrode 17.
• Screw FEP tubing 38 for the inert gas supply into connection 73 of the
multi-mode electrode 17.
• Attach electrode cable 16 (WE) to screw connection 89 of the multi-mode
electrode 17: push cable lug under the screw and then tighten screw
firmly.