Metrohm 746 VA Trace Analyzer - Manual (Page 53)

3 Installation
746 VA Trace Analyzer / 747 VA Stand
3-26
6 Replace sealing needle 97 97 if need be
If problems with leaks arise owing to a worn, deformed or damaged sealing
needle 97 97 (see sections 7.4.2 and 7.4.3), this must be replaced. Three spare
needles are supplied separately in a protective plastic package. After un-
packing a needle, please avoid any contact whatsoever with the needle tip.
The spare needle 97 97 is installed as follows:
• Carefully pull old sealing needle 97 97 out of PTFE membrane of the slotted
screw 96 96.
• Carefully insert new sealing needle 97 97 without tilting into the hole in the
PTFE membrane of the slotted screw 96 96.
When the sealing needle 97 97 is changed, it is always necessary to
change the glass capillary 109 109 !
7 Replace sealing ring 106 106 if need be
• If the sealing ring 106 106 is contaminated or damaged in any way (see
sections 7.4.2 and 7.4.3), it must be replaced for the subsequent assem-
bly of the MME. Two new sealing rings 106 106 are enclosed in the package
with the 6.1226.030 glass capillaries.
8 Reassemble MME
• Screw slotted screw 101 101 using a suitable coin flush into screw thread
100 100.
Do not turn so tightly that the cemented-in steel threaded ring 100 100
becomes loose and hence jeopardizes the tightness and safety of the
MME!
• Using a suitable coin, screw slotted screw 96 96 into the screw thread 98 98
until the contact surface of the black O-ring at the Plexiglas wall (thin,
black stripe) is just visible below the metal thread 98 98.
• Place multi-mode electrode 38 38 with the opening 104 104 facing upwards in
the electrode holder 114 114 (see Fig. 15-1).
• Insert insert ring 105 105 in opening 104 104.
• Push sealing ring 106 106 onto locking ring 107 107 and insert both in the open-
ing 104 104.
• Screw retaining nut 108 108 by hand into screw thread 104 104 until a slight
resistance is felt.
9 Add mercury
Proceed as described in section 3.4.2.
10 Mount new capillary
Proceed as described in section 3.4.3.
11 Fill capillary
Proceed as described in section 3.4.4 or section 3.4.5.