Xylem MJK pHix Compact, Manual

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pHix® Compact
EN 4.10 Version 2007
Maintenance / Maintenance in general
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Maintenance
Maintenance in general
A pH or redox measuring system requires maintenance with regular intervals.
Cleaning and buffer adjustment (calibration) is a normal and necessary
maintenance that should be carried out regularly.
Intervals
The interval between buffer adjustments and cleaning depends widely on the
working conditions. Therefore, the easiest way to find the most appropriate
cleaning interval is by feeling one's way.
For instance, start out by cleaning and buffer adjusting every week.
If measurements are unchanged or just slightly changed after buffer
adjustment, the electrode were not dirty or just slightly dirty, and the cleaning
interval can be changed to two weeks and after that, one month.
The intervals are equally reduced if the electrodes are very dirty and the
measurements are significantly changed after buffer adjustment.
There are no general guidelines to cleaning and adjustment, but in most cases,
a monthly adjustment is sufficient. Before beginning a buffer adjustment, the
electrode must be thoroughly washed:
first in running water
then, if necessary, in a degreasing fluid, like, for example a 10%
hydrochloric acid solution
then, before the electrode is put into the buffer solution, and again in
between every step of the buffer adjustment, rinse with water and dry
with a dry cloth.
Redox electrodes
Like pH electrodes, Redox electrodes require cleaning but not buffer
adjustment. However, MJK does deliver redox buffers for control of electrode
and transmitter.
If the transmitter does not show the correct value when put into the buffer
solution, the electrode must be exchanged.