Metrohm Multi-Mode Electrode pro - Manual (Page 37)

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5 Maintenance
6.1246.120 Multi-Mode-Electrode pro
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Note
If you use another software than 797 VA Computrace, then follow the
instructions on adjusting the needle valve in the manual of your instru-
ment.
For adjusting the needle valve you need the wrench (6.1247.220) or a
coin which will fit the slot of the screw.
1 Preparation
￭ Place an empty measuring vessel.
￭ Set the inert gas supply to 1.0 to 1.2 bar, in order to pressurize
the electrode.
￭ In the 797 VA Computrace software, open the dialog Compu-
trace Control with Utility
▶ Computrace Control and select
the electrode type HMDE.
￭ As soon as a drop of mercury appears at the tip of the capillary,
fill approximately 20 mL of water and a few drops of KCl-solution
into the measuring vessel.
2 Rough adjustment
￭ With the wrench, rotate the screw of the needle holder (1-1)
clockwise until the mercury stops dropping.
Check: After each half rotation of the screw, knock off the drop
and check if a new drop is forming.
3 Fine adjustment
￭ Rotate the screw slowly counterclockwise until a new drop is
forming.
￭ Reseal the capillary with a small rotation in clockwise direction
(ca. 10°).
￭ Rotate the screw clockwise by another quarter rotation (90 –
100°).
The MME pro is now ready for operation.