Anyone who has dealt with the topic of flow measurement will know that a corresponding measuring instrument costs several thousand euros. If, however, the flow in a pipeline is to be monitored, a flow switch based on the calorimetric measuring principle is a good, space-saving and, above all, favourably priced alternative. So how do flow meters differ from flow switches?
Wherever gases or liquids are charged based on their consumption, the use of precision flow measuring instruments cannot be avoided. These determine volume or mass flows with a measuring deviation of approximately two percent or better.
Flow switches, also called flow monitors, do not work by detecting flow volumes per unit of time; they are merely intended to detect the presence or absence of flow. In this context, the measuring accuracy plays a lesser role since in the first place a switching mechanism is to be initiated ‒ meaning, on reaching a defined flow velocity, a contact switches with a non-repeatability of between two and five percent. Typically, calorimetric flow switches are used in cooling circuits, cooling lubricant systems in machine tools, in filter units or as dry run protection in pumping stations.