Several common senses that must be mastered when buying a ph meter and a PH acidity meter
⑴ Classification according to the application: can be divided into pen type PH meter, portable PH meter, laboratory PH meter and industrial PH meter, etc. The pen-type pH meter is mainly used to replace the function of pH test paper, and has the characteristics of low precision and convenient use. Portable pH meters are mainly used for on-site and field measurements, requiring high precision and perfect functions.
⑵ Classification according to the accuracy of the instrument: it can be divided into 0.2, 0.1, 0.02, 0.01 and 0.001. The smaller the number, the higher the accuracy.
⑶ Classification according to the reading indication: it can be divided into two types: pointer type and digital display type. Pointer pH meters are rarely used now, but pointer meters can display the continuous change process of data, so they are still used in titration analysis.
(4) Classification according to the type of components: it can be divided into transistor type, integrated circuit type and single-chip microcomputer type. Now more microcomputer chips are used, which greatly reduces the size of the instrument and the cost of a single machine; but the development cost of the chip is very expensive. Laboratory pH meter: The laboratory pH meter is a desktop high-precision analytical instrument that requires high precision and full functions, including printout, data processing, etc. Industrial pH meter: Industrial pH meter is used for continuous measurement of industrial processes. It not only has measurement display function, but also has alarm and control functions, as well as installation, cleaning, anti-interference and other issues.
Features of pH Meter
The glass on the pH electrode will gradually age over time, the gradient (the change value of the electrode output potential caused by the change of unit pH value) will deteriorate, and it will take a long time to reach a stable potential. The service life of general electrodes can reach two years. In addition, temperature also has a great influence on aging. The aging degree of storage at 100°C for several weeks is equivalent to the aging degree of storage at room temperature for one year.
The pH meter has the advantages of accurate measurement, high reliability, and convenient installation and maintenance. It is also sensitive to pollution and requires frequent calibration. Generally, it is calibrated every one to one and a half months, and the electrode is replaced every two years.
