Flow measurement involves a wide range of application fields. The demand for flow measurement in high energy consuming fields such as process measurement, energy metering, environmental protection, and transportation is rapidly increasing, posing new requirements for flow measurement technology. Not only is it required that the flow measurement instrument be resistant to high temperature and high pressure, but it can also automatically compensate for the impact of parameter changes on measurement accuracy. Considering special requirements in energy conservation, cost accounting, trade, and medical and health, high accuracy, low pressure loss, and high reliability are required for flow measurement.

The development and application of new technologies, devices, materials, processes, and software have led to higher measurement accuracy and wider measurement range of flow meters. At the same time, the requirements for measuring media in flow meters are decreasing, and their applicability is becoming wider. The level of intelligence and reliability have been greatly improved.

In the previous article, we introduced measurement techniques for small and large flow fluids. Today, we will continue to introduce flow measurement techniques for corrosive media and multiphase fluids.

Flow measurement of corrosive media

Corrosion is the phenomenon of metal being damaged in its environment due to chemical reactions. All metals and alloys can be corrosion-resistant to certain specific environments, but sensitive to corrosion in others. Generally speaking, industrial metal materials that are resistant to corrosion in all environments do not exist.

Corrosion can be divided into uniform corrosion, general corrosion, and localized corrosion. The corrosion rate of comprehensive corrosion can be expressed in units such as mm/a (number of millimeters corroded per year). Materials with a corrosion rate below 0.1mm/a are usually considered corrosion-resistant materials. For materials with a corrosion rate of another order of magnitude higher than this, i.e. a corrosion rate of 1mm/a, it can sometimes be considered as a usable material for general equipment. For measuring elements of flow meters, they are not allowed. Based on the corrosion rate, the service life of the metal can be predicted.