BrandTech Scientific Dispensette TA - Manual (Page 42)

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Cleaning
Cleaning for trace analysis
Before use in trace analysis, the instrument must first be thoroughly
cleaned. Pure chemicals used for analytical purposes are used for
this cleaning procedure. If contamination of the bottle contents must
be avoided, use the instrument without the SafetyPrime
™ recircula-
tion valve. If the instrument is used with the SafetyPrime ™ recircu-
lation valve, it must be cleaned in both dispensing and recirculation
modes (Fig. 1 and 2).
Good results have been obtained in practice with the following
recommended cleaning procedures. They can be modified according
to need.
1.
Screw the instrument onto a bottle filled with Acetone, prime it
and then fill it completely.
Leave the piston at the upper stop and close the dispensing tube
with the screw cap.
After approx. 24 hours contact time, dispense twice, then
completely empty the instrument and rinse it five times with pure
water.
2.
Screw the instrument onto a bottle filled with 20% hydrochloric
acid, prime it and then fill it completely. Leave the piston at the
upper stop and close the dispensing tube with the screw cap.
3.
After approx. 24 hours contact time, dispense twice, and then fill
it up again completely.
4.
Repeat step 3 twice more.
After another approx. 24 hours contact time, completely empty
the instrument and rinse it five times with pure water.
5.
Repeat steps 2 to 4 with 30% nitric acid.
6.
Screw the instrument onto a bottle filled with the desired dis-
pensing medium, prime it, and then fill it completely. Leave the
piston at the upper stop and close the dispensing tube with the
screw cap.
7.
After approx. 24 hours contact time, dispense twice, and then fill
it up again completely.
8.
Repeat step 7 twice more. After another approx. 24 hours
contact time, dispense twice and then leave the piston at the
lower stop.
If the cleaning is not sufficient, repeat the cleaning procedure.
Note: