YOKOGAWA PH72-21-E-AA, User Manual

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IM 12B03D02-01E
8-2
8. ORP Meter
8.2 Maintenance of ORP Sensors
Maintenance of ORP sensors is in accordance with that of pH sensors. (Refer to Chapter
6, “Maintenance.”)
Cleaning the Platinum Electrode and Liquid Junction
Dirt or deposits on the platinum electrode or liquid junction may interfere with accurate
measurement. Periodical cleaning is required depending on the nature of the solution
being measured.
As in the same manner for pH sensors, use a cotton swab or brush to clean. (See Section
6.2.) If the potential is outside the tolerance after the sensor check has been performed
according to the procedure in Section 8.3, clean the platinum of the sensing electrode.
Polish the platinum using a cream cleanser, alumina powder, or baking soda (sodium
bicarbonate), and then wash with water.
CAUTION
Do not apply physical shock or excessive force to the glass sensor, or it may break.
Replenishment of Electrode Filling Solution
When the level of KCl filling solution drops, replenish following the procedure in
Section 6.5.