Industrial pH Meters: Maintenance and Calibration
(1) In areas with significant temperature differences, pH meters must be equipped with temperature compensation to eliminate the impact of environmental temperature on the pH meter. In winter, strengthen the insulation of pH meters and their pipelines to ensure that the temperature is controlled within the range of 17-21 ° C. The stability of pH meters in summer is significantly better than in winter, with temperatures controlled below 45 ° C.
(2) When adjusting the pH meter, the ambient temperature should be maintained at 25 ° C. When setting the temperature compensation, it should be consistent with the temperature of the process medium.
(3) Pay more attention to the process production situation, such as abnormal production, process production shutdown, etc., and promptly check the pH meter.
① Check if there is liquid in the circulation pool. If there is no liquid, the process medium may dry up and adhere to the electrode, making it impossible to measure during further production.
② If there is low temperature or crystallization in the process medium, the pH meter should be removed for protective treatment. The composite glass electrode should not be placed upside down.
③ The pH meter removed from parking must be immersed in a pH 4 buffer solution containing KCl for the pH composite electrode to function simultaneously with the glass bulb and liquid interface. If the conditions are not met, the pH detection head can also be soaked in pure water and stored without oxygen, and must not be left unprotected in the air.
(4) According to the specific situation, it is not a problem to calibrate once a month, so try to calibrate as little as possible. The biggest bottleneck of pH meters is their service life, especially the reference electrode, which is easily contaminated and poisoned. If the reference electrode is damaged, the pH meter is basically scrapped.
(5) The conductivity of the measured solution affects the accuracy of the measurement. Common industrial pH meters require the conductivity of the measured solution to be no less than 50 μ S/cm. In addition, it is closely related to the working conditions, such as sulfur-containing and alkaline working conditions, and special attention should be paid. If necessary, the laboratory should conduct sampling analysis to determine the disturbance of the pH meter.
