Self-cleaning methods are recommended for online pH electrodes.
Self-cleaning methods are recommended for online pH electrodes. While online pH electrodes are widely used in industrial fields, the degree of contamination varies with different measuring media, so different cleaning methods are adopted for online pH electrodes.
For online pH meters, if the measured medium is relatively clean (such as demineralized boiler feed water), the pH electrode suffers mild contamination. The electrode can be taken out for cleaning regularly based on experience. However, this method is less and less used in online detection. Manual cleaning is labor-intensive and time-consuming; it also interrupts measurement and affects automatic detection. Therefore, automatic cleaning is recommended for online pH meters. The online pH meters from Anhui Saike Environmental Protection Technology adopt an automatic cleaning method combining ultrasonic cleaning and solution jet cleaning for industrial pH electrodes.
① Ultrasonic Cleaning An ultrasonic generator is installed near the pH probe of the pH meter. It emits ultrasonic waves to automatically clean the pH electrode. The intensity of ultrasonic waves is adjusted by changing the oscillation frequency. The device is installed vertically, with the ultrasonic probe mounted below the electrode.
② Solution Jet Cleaning Cleaning nozzles are fitted near the electrode assembly. According to cleaning requirements, the nozzles spray water or other solutions (such as low-concentration hydrochloric acid and nitric acid solutions) periodically to remove contaminants on the electrode by scouring or dissolution. For example, the supporting self-cleaning system uses 1% dilute HNO₃ solution by mass fraction as cleaning liquid, and the spray pressure is generally higher when using water. The solution spraying is controlled by a program controller. During spraying, the online pH meter shall keep the control output unchanged at the value before cleaning, namely locking the instrument output. The instrument output remains constant during cleaning. After cleaning is completed and the pH value of the solution stabilizes, the pH meter resumes detection and output. In summary, the combined method of ultrasonic cleaning and solution jet cleaning delivers good results for cleaning industrial online pH electrodes.
