Metrohm 700 Dosino - Manual (Page 34)

3. The Dosino in practice
700 Dosino, Instructions for Use
28
3.3 Cleaning and maintenance
Unlike the dosing units the dosing drive requires no special main-
tenance. You should ensure that it is not exposed to excessive dirt
or corrosive influences. If aggressive reagents are dosed with
Dosino burets then, when the dosing unit is not in use, it should be
rinsed with an inert solvent (
'PREP' function) and then emptied
( 'EMPTY' function). The dosing drive should be removed during
longer periods (more than one week) of non-use .
Dosing units require to be checked regularly and be cleaned
frequently.
If alkaline, corrosive or concentrated reagents are used then a
check has to be done once a month or even once a week. Other
reagents may allow the inspection period to be extended to six or
twelve months.
The way in which a dosing unit is dismantled is shown on page
13ff.
3.3.1 Cleaning the cylinder and piston
• Check the tightness of the dosing piston and cylinder. If there is
liquid above the piston this means that the dosing cylinder is
either not lubricated at all or is not adequately lubricated. Check
whether the sealing lips are deformed or damaged; if they are
then the piston and the cylinder must be replaced.
• Clean the dosing cylinder and piston with a liquid detergent. Do
not use abrasive powders as these could scratch the cylinder.
Then thoroughly rinse the individual components with deionized
or distilled water.
• Degreasing the piston and the glass cylinder is part of the
cleaning process. Use an appropriate cleaning agent or solvent
and possibly an ultrasonic bath. Follow the manufacturer's rec-
ommendations.
• Before reassembling the dosing unit check the piston and cylin-
der again for changes. If the dosing cylinder is scratched or has
rough surfaces it must be replaced.
• In order to ensure that the Dosino buret does not leak it must
be slightly lubricated. Carefully apply a little 6.2803.000 Grease
(silicone-free) with your finger to the outside of the piston and
wipe off any excess grease with a soft lint-free cloth.