Use Of Ph Sensor; Operation And Periodical Maintenance; Buffer Solution Calibration; Pressurizing Reserve Tank - YOKOGAWA PH8ECP User Manual

3. USE OF pH SENSOR
3.1 Operation and Periodical Maintenance
3.1.1 Buffer Solution Calibration
Calibrate with buffer solution before starting normal operation because the e.m.f. of the glass
electrodes differ a little from each other. The e.m.f. of the glass electrode gradually changes due
to electrode staining and electrode deterioration. Therefore, the buffer solution calibration must be
performed periodically within a given period to keep the measurement error within tolerance.
Refer to the Section "OPERATION" in the instruction manual of the pH converter or two-wire
transmitter for instructions for buffer solution calibration.
Note: Glass electrodes which have dried out do not show stable properties until some time after immersion in solution. Submerge the
electrode in water for about 30 minutes to stabilize its characteristic before carrying out buffer solution calibration.
3.1.2 Pressurizing Reserve Tank
When the pH sensor with medium pressure reserve tank is used, apply air pressure to the reserve
tank before flowing the measured solution through the holder.
Set the air pressure a little higher than the maximum pressure of the measured solution during the
operation.
The flow rate of the KCl solution from the liquid junction is approximately 2 mL/day when the pressure
difference between air and measured solution is 10 kPa and the flow rate increases in proportion to
the pressure difference.
< 3. USE OF pH SENSOR >
IM 12B7J3-01E
3-1
7th Edition : Nov.20,2018-00