What is a pH meter?
A pH meter is an digital instrument used to test and monitor the pH value of a solution. It works by the principle of primary battery, of which the electromotive force between two electrodes is based on the Nernst Law. Electromotive force of primary battery is affected by both property of electrodes and hydrogen ion concentration in the solution. There is a correspondence relationship between the electromotive force and hydrogen ion concentration of the primary battery, namely negative logarithm of the hydrogen ion concentration is equal to the pH value.
PH meter is an ordinary analytic instrument and is widely used in agriculture, environmental protection, industry and other fields. PH meters can be categorized as pen type pH meter, benchtop pH meter, handheld pH meter, laboratory pH meter and industrial online pH meter.
Pen type (mini) pH meter and portable pH meter are generally used by testing personnel on site. Portable pH meter and benchtop pH meter are common instruments with wide measuring range, the difference is that portable pH meter uses the DC power supply, so it can be taken to work field. Laboratory pH meter has wide measuring range, various functions and high measurement accuracy.
Industrial online pH meter is more stable and reliable and have certain measurement accuracy, strong environmental adaptability and strong anti-interference ability, as well as functions of analog output, digital communication, upper and lower limit alarm, control function, etc. For a measurement at 20～30℃ and pH value 7, there is no need temperature compensation. For a measurement at a temperature above 30℃ or below 20℃ while the pH value is higher than 8 or lower than 6, temperature variation must be compensated.
Using an industrial online pH meter can better control the chemical reactions to improve productivity, product quality and safe production. A pH measurement system with automatic recording can also provide evidence of litigation against pollution hazards. Some batch production processes (such as some fertilizer production or food processing processes) can be converted to continuous production by using a digital pH meter. In modern industry, the usage of pH meters is almost the sum of other types of continuous analytical meters.
A pH meter is required in almost every production department that uses water. Its applications range from industrial water, waste treatment to flotation in mining, and also pulp and paper, metal processing, chemical engineering, petroleum, synthetic rubber production, power plants, pharmaceuticals, food processing and other fields.