wtw TriOxmatic 701, Руководство по эксплуатации

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Maintenance, cleaning, disposal, spare parts
39
4.4 Checking whether the probe is zero current
free
The probe is zero current free. Therefore, it is not possible
to calibrate the probe in air free of oxygen.
It is possible, however, to check whether the probe is zero
current free according to DIN EN 25814/ISO 5814. This is
required in case of a suspected malfunction.
Test solution 1 g/L aqueous sodium sulfite solution, Na
2
SO
3
(adding 1 mg/L of a cobaltous salt accelerates the removal
of oxygen from the solution.)
The probe should have been in operation for at least one
hour before the check.
Course of the check  Perform an exterior cleaning of the probe.

Switch the measuring instrument to the % saturation
operating mode.
 Immerse the probe into the test solution.

Wait for one hour.
Note
Leave the probe in the test solution for one hour.
Test criterion The probe is OK when the measuring instrument displays <
1 % oxygen saturation.
If the measured value is > 1 %:

Clean the gold working electrode and replace the
electrolyte and membrane head.

If necessary, also clean the counter electrode (see
chapter 4.2.1 C
LEANING THE GOLD WORKING ELECTRODE
to
chapter 4.3 R
EFILLING THE MEMBRANE HEAD
).