Metrohm 797 VA Computrace - Manual (Page 30)

2 Installation
797 VA Computrace / Hardware-Manual 8.797.8001EN
22
2.3.2 Filling the MME with mercury
When handling mercury, it is necessary to take special precautionary
measures. These are described in detail in section 3.4.
All actions involving the electrode and mercury vessels must be perfor-
med in or over the drip pan 91 supplied (see Fig. 9 - Fig. 11).
The Hg reservoir 81 of the Multi-Mode Electrode 21 is filled with mercury of the hig-
hest degree of purity (mass fraction w ≥ 0.99999) as follows:
1 Prepare Multi-Mode Electrode
• Unscrew locking ring 73 from slotted screw 74 (this gray PVC ring is nee-
ded only to remove the slotted screws 74 or 79, see section 2.3.7 and sec-
tion 2.3.9).
• Turn slotted screw 74 in or out of the screw thread 76 using a suitable
coin until the contact surface of the black O-ring at the Plexiglas wall (thin,
black stripe) is just visible below the metal thread 76.
• Remove the plastic cap used as a transport safeguard from the retaining
nut 86.
• Undo retaining nut 86 fully and remove from screw thread 82.
• Place Multi-Mode Electrode 21 with the capillary opening facing upwards
in the electrode holder 92 (see Fig. 9).
Fig. 9: Adding the mercury
21 Multi-Mode Electrode (6.1246.0020)
89 Syringe (6.2816.020)
90 Needle (6.2816.030)
91 Drip pan (6.2711.030)
92 Electrode holder (6.2615.030)
Hg
90
89
91
21
92