Treatment of Common Faults in online PH meter
1. Aging of glass electrode
Phenomenon: response lag; Sensitivity decreases; Zero drift.
Handling:
(1) electrode calibration on a regular basis.
⑵ Electrode activation: The aged electrode can be soaked in the mixed solution (1:1) of 1M acetic acid and 1M potassium chloride, and then taken out and cleaned after 10min of activation. Electrodes that are not seriously aged can be soaked in distilled water or 0.1N dilute hydrochloric acid solution to activate for 24h.
2. Glass electrode pollution
Phenomena: decreased sensitivity; Measurement deviation.
Handling:
(1) The alkaline precipitate on the electrode can be cleaned in dilute hydrochloric acid solution, and then the electrode can be cleaned with distilled water.
⑵ Grease attached to the electrode can be cleaned with hot water and household detergent, or scrubbed with gauze.
(3) Colloidal dirt can be cleaned with strong hydrochloric acid solution, and the electrode should be cleaned with distilled water after washing.
(4) After cleaning with acid, alkaline solvent or organic solvent, the electrode should be soaked in distilled water for a period of time, so as to restore the damaged hydration layer.
3. Contamination of reference electrode (ceramic plug blocked)
Phenomenon: the measured value is high; The indication is unstable.
Treatment: it can be cleaned with hot water and household detergent; Oily or alkaline dirt can be cleaned with organic solvent (such as alcohol) or dilute hydrochloric acid solution; If the pollution is serious, it can be brushed with a soft brush or wiped with filter paper strips. For non-flow electrode, the electrode can be placed in electrolyte at 80℃ until the electrolyte cools.
4. Reference electrode poisoning
Phenomenon: wrong indication; Indication is unstable; Unable to correct.
Treatment: if only the electrolyte in the reference electrode is polluted, replace the electrolyte; If the non-flow electrode or internal electrode is poisoned, the electrode needs to be replaced.
5. The impedance of the signal cable to the ground is reduced (< 107 Ω)
Phenomenon: indicates instability and jump; The display is out of range and cannot be measured.
Treatment: replace the cable and dry the cable plug or junction box with a hair dryer.
