A large number of different measuring principles apply to the area of flow measurement. In general, these can be distinguished between according to mechanical or electronic principles. It is also possible to differentiate between invasive and non-invasive active principles, i.e. those which “intervene”, or do not intervene, in the medium to be measured.
Each measurement principle has advantages for certain applications but also disadvantages compared with the others. Unfortunately, there is no “absolutely perfect solution” which works optimally for every application. A magnetic inductive flow sensor is suitable for the measurement of aqueous media, for example, but its physical principle of action means that it is not suitable for electrically non-conductive media such as oil, etc.