Cleaning For Trace Analysis; Replacing Discharge Tube/Valves - BRAND Dispensette S Mode D'emploi

9 Cleaning

9.2 Cleaning for trace analysis

Before use in trace analysis, the instrument must first be thoroughly cleaned. In doing so, use
reagents having the purity level "per analysis" or better. If contamination of the bottle contents
should be avoided, do not use the instrument with a recirculation valve. If the instrument is used with
a recirculation valve, the cleaning must be done using both the dispensing and recirculating function
(see Figures 1 and 2).
Good results have been achieved in practice with the following recommended cleaning methods.
Modify accordingly, as necessary.
1
Dosing function
2
Recirculation function

9.3 Replacing discharge tube/valves

The valves, telescoping filling tube and discharge tube contain reagent!
Contact with potentially hazardous media is possible.
> Clean the instrument before the discharge tube, valves or dosing unit are exchanged.
> Do not disassemble the dosing unit.
> Follow the safety instructions (Safety Instructions, p. 34).
50
Operating manual
a.
Screw the device onto a bottle filled with acetone,
deaerate and fill up to the maximum.
Leave the piston at the upper stop and close the dis-
charge tube with the screw cap.
Dispense twice after approx. 24 hours reaction time,
then the device must be completely drained and rinsed
5 times with pure water.
b.
Screw the device onto a bottle filled with approx. 20 %
hydrochloric acid, deaerate and fill up to the maximum.
Leave the piston at the upper stop and close the dis-
charge tube with the screw cap.
c.
After approx. 24 hours reaction time, dispense twice
and fill again to the maximum.
d.
Repeat step 3 two more times.
After another 24 hours of reaction time, completely
drain the device and rinse it 5 times with pure water.
e.
Repeat steps 2 to 4 with a solution of approx. 30% nitric
acid.
f.
Screw the device onto a bottle filled with the desired
dispensing medium, deaerate and fill up to the maxi-
mum. Leave the piston at the upper stop and close the
discharge tube with the screw cap.
g.
After approx. 24 hours reaction time, dispense twice
and fill again to the maximum.
h.
Repeat step 7 two more times. After an additional
24 hours reaction time, dispense twice and leave the
piston at the lower stop.
If the cleaning is insufficient, repeat the cleaning process.
WARNING
NOTICE
9974 91