How to clean the electrode of online ph meter?
Online ph meter electrode is suitable to adopt self-cleaning method. Online ph meter electrode in the industrial field of widespread use at the same time, the measurement of different media, the degree of contamination is not the same, so the online ph meter electrode using different cleaning methods. Online acidity meter, if the measurement medium is relatively clean then the degree of contamination on the ph meter is light, can be based on experience to regularly remove the electrode for cleaning.
But this method is less and less used in online testing. Because of artificial cleaning is not only labour-intensive, time-consuming, and will make the measurement interrupted, affecting the automatic detection, so the online ph meter should be used automatically cleaning. Here are 2 commonly used cleaning methods:
1, ultrasonic cleaning
In the acidity meter ph meter probe near the installation of a device that can generate ultrasonic waves, which sends ultrasonic waves on the PH electrode for automatic cleaning. Ultrasonic strength by adjusting the oscillation frequency of ultrasonic waves to achieve. It is installed in a longitudinal way, that is, the ultrasonic probe is installed below the electrode.
2,Solution Jet Cleaning
In the vicinity of the electrode assembly is equipped with a cleaning nozzle, according to the cleaning requirements, the nozzle regularly spray water or other solutions (such as low concentration of hydrochloric acid, nitric acid solution) to remove the pollutants on the electrode in order to flush or dissolve the way. Such as the use of self-cleaning system with a mass fraction of 1% of the dilute HNO3 solution as a cleaning solution, while the water is generally sprayed with a higher pressure. The spraying of the solution is controlled by the programme controller. In the spray, the online ph meter needs to be able to control the output to maintain the value before cleaning unchanged, that is, at this time to lock the instrument output, the instrument output during the cleaning period to remain unchanged, to be cleaned to complete the ph value of the solution stabilised, the ph meter and then test the output. In short, the use of ultrasonic cleaning and solution jet cleaning combination of industrial online ph meter electrode cleaning, the effect is better.
ph meter electrode clogging is caused by the liquid junction clogging, can be solved by the following methods:
1. soak ph meter electrode liquid junction: with 10% saturated potassium chloride solution and 90% distilled water mixture, heated to 60 ~ 70 ℃, the ph meter electrode immersed in about 5cm, immersed for 20 minutes to 1 hour, can be dissolved at the end of the ph meter electrode crystals.
2. Ammonia immersion ph meter electrode: when the liquid junction is blocked by silver chloride can be concentrated ammonia immersion. First of all, the ph meter electrode will be washed and emptied after immersed in ammonia for 10 to 20 minutes, but do not let the ammonia into the ph meter electrode inside, remove the ph meter electrode with distilled water to wash, rejoin the internal charging liquid and continue to use.
3. Vacuum method: put the hose over the liquid junction of the reference electrode, use the water flow suction pump to pump part of the internal liquid through the liquid junction, remove the mechanical blockage.
4. Boiling liquid junction: the liquid junction of silver-silver chloride reference electrode is immersed in boiling water for 10 to 20 seconds, in addition, before the next boiling, the ph meter electrode should be cooled to room temperature.
5. When the above methods are ineffective, the mechanical method of grinding with sandpaper can be used to remove the clogging of the ph meter electrode. This method may cause the sand particles under the grinding to be plugged into the liquid junction, resulting in clogging.
