With this design a range of interchangeable metering plugs may be provided within one body size, such that flow ranges may be changed very simply.

Construction is in stainless steel as standard but other materials may be used to suit the corrosive properties of the metered fluid. Flanges to ANSI, BS4504 or BS10 may be fitted and a design is also available with Ermeto or BSP couplings for high pressure hydraulic work.

In operation a star shaped paddle wheel is housed within a metering plug containing a small jet hole such that a high velocity jet is imparted tangentially on the rotor. Rotational speed and hence frequency are directly proportional to flowrate. The sharp edges of the rotor are detected by a reluctance pick off coil and an alternating voltage is thus generated.