3.3 Multi-mode electrode (MME)
757 VA Computrace – Hardware
23
3.3.2
Filling the MME with mercury
When handling mercury, it is necessary to take special precautionary
measures. These are described in detail in section 4.2.
All actions involving the electrode and mercury vessels must be
performed in or over the drip pan
92
supplied (see Fig. 10).
The Hg reservoir
82
of the multi-mode electrode
17
is filled with mercury of the
highest degree of purity (mass fraction
w
≥
0.99999) as follows:
1 Prepare multi-mode electrode
•
Unscrew locking ring
74
from slotted screw
75
(this gray PVC ring is
needed only to remove the slotted screws
75
or
80
, see
section 3.3.7
and
section 3.3.9
).
•
Turn slotted screw
75
in or out of the screw thread
77
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
77
.
•
Remove the plastic cap used as a transport safeguard from the retaining
nut
87
.
•
Undo retaining nut
87
fully and remove from screw thread
83
.
•
Place multi-mode electrode
17
with the capillary opening facing upwards
in the electrode holder
93
(see
Fig. 9
).
90
91
92
17
93
Hg
Fig. 9: Adding the mercury
17
Multi-mode electrode
(6.1246.0020)
92
Drip pan (6.2711.030)
90
Syringe (6.2816.020)
93
Electrode holder
(6.2615.030)
91
Needle (6.2816.030)
