wtw Turb 550, Operating Manual

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Operation
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4.2 Measuring turbidity
4.2.1 Standard measurement
Preparatory
activities
Perform the following preparatory activities when you want
to begin measuring:
Note
Incorrect calibration of the turbidity measuring instrument re-
sults in incorrect measured values. Carry out the calibration
regularly at the specified fixed intervals.
Note
The outside of the cell must always be clean, dry and free of
fingerprints. Clean the cell before starting to measure (see
5.2.2 C
LEANING THE CELLS
). Only hold the cells at the top or
by the black light protection cap.
Measuring How to measure the turbidity of a sample:
1 Switch on the instrument
2 Wait for at least 30 minutes to allow for the warm-up
time.
1 Rinse out a clean cell with the sample to be mea-
sured:
Pour approximately 20 ml sample into the cell. Close
the cell and rotate it several times before throwing the
sample away
2 Repeat the rinsing procedure twice more
3 Fill the cell with the sample to be measured (approx.
30 ml). Close the cell with the black light protection
cap
4 Make sure that the outside of the cell is clean, dry and
free of fingerprints
5 Insert the cell in the cell shaft of the turbidity measur-
ing instrument