EU RO Mutual Recognition Group

General description of the product

Fluid flow switches are generally made of a casing containing the switch and a probe or other similar device projecting from the same and immersed in, or in other ways sensing the presence of, the fluid flow (set-in type). The device may include a short pipe fitting (flow-through type): in this case, the pipe fitting as well as any other component subject to internal pressure of fluid is not covered by the scope of the present Technical Requirement.

Based on the principle of operation, the following types are considered: mechanical flow switches (e.g. paddle-type, shuttle-type, piston-type) and pressure-based flow switches (e.g. differential pressure).

In general, flow switches are intended to open/close an electrical circuit (signal) upon reaching of a certain set point of flow, and are actuated by the energy conveyed by the fluid. Electronic components, when fitted, may be supplied by an external source of power or by internal batteries. Software based flow switches are not covered by the scope of this TR.