The non sharp edge profile is preferable in more abrasive fluids and at higher temperatures, such as water or vapour. The Flow Nozzles have a rounded inlet profile and a narrow cylindrical linear section.
With the same size, they allow measurement for higher flow rates than orifice plate.
The ISO 5167 std, provides three types: the “ISA 1932 Nozzle”, the “Long Radius Nozzle” and the “Venturi Nozzle”.