Metrohm 746 VA Trace Analyzer - Manual (Page 50)

3.4 Multi-mode electrode (MME)
746 VA Trace Analyzer / 747 VA Stand
3-23
3.4.7 Replenishing the mercury (without changing capillary)
The multi-mode electrode 38 38 can also be refilled with mercury without having to
remove the glass capillary 109 109.
1 Dismantle multi-mode electrode
• Unscrew FEP tubing 51 51 and 59 59 from the MME. Disconnect electrode
cable 37 37 from the MME.
• Take multi-mode electrode 38 38 out of the measuring head 41 41 and tap the
MME gently to knock off any mercury drops on the glass capillary into the
measuring vessel.
• Place multi-mode electrode 38 38 horizontally in the electrode holder 114 114
(see Fig. 15-3). The slotted screw 101 101 is now at the top.
2 Replenish mercury
• Unscrew slotted screw 101 101 using a suitable coin. If the slotted screw 101 101
can not be loosened by hand, screw on locking ring 95 95 and pull out of the
MME.
• Draw up mercury using the syringe 111 111 with attached needle 112 112 and
expel into the Hg reservoir 103 103.
The Hg reservoir 103 103 must never be filled more than 2 /
3
full with
mercury.
• Reinsert slotted screw 101 101 into screw thread 100 100 and screw flush to
surface using a suitable coin (this action may expel a few drops of mer-
cury from glass capillary 109 109).
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!