11
10
CONDUCTIVITY PROBE MAINTENANCE
Rinse the probe with tap water after
every series of measurements.
If a more thorough cleaning is re-
quired, remove the sleeve and clean
the probe with a cloth or a non-
abrasive detergent.
After cleaning, re-calibrate the in-
strument.
The 4-platinum-ring probe body is
made with glass. For this reason,
great care must be taken while
handling the probe.
• Immerse the probe into a sample of the solution and adjust the
conductivity TC knob to 0% (i.e. no compensation).
• Condition sample and probe at 25°C, and note the conductivity
reading C
25
.
• Condition sample and probe to a temperature T, approximately
5°C to 10°C different from 25°C, and note the conductivity
reading C
T
.
• The temperature coefficient
β
of the solution is calculated with the
following formula:
β
= 100 x (C
T
-C
25
) / [(T - 25) x C
25
]
The above procedure is suitable for determining the temperature
coefficient in the laboratory where the temperature of the solution can
be determined and controlled. If this is not possible, e.g. during field
measurements, the following procedure should be used:
• Immerse the probe into the test solution and turn the conductiv-
ity TC knob to 0% (no compensation).
• Allow the reading to stabilize (the reading should not change by
more than ±0.2 mS within 1 minute) and record the value, C.
• Repeat the procedure with the temperature of the solution
changed by more than 10°C. Wait for the conductivity reading to
stabilize.
• Adjust the conductivity TC knob until the display shows the
previously recorded C value.
• The value indicated by the knob is the temperature coefficient of
the solution.
DETERMINATION OF THE TEMPERATURE
COEFFICIENT OF A SOLUTION
