Each pulse represents a discrete volume of liquid. As each blade passes the coil, a voltage is generated in the coil (Figure 1-A). In the reluctance pick-up, the coil is a permanent magnet and the turbine blades are made of a material attracted to magnets. Turbine rotation can be detected by solid state devices (reluctance, inductance, capacitive and Hall-effect pick-ups) or by mechanical sensors (gear or magnetic drives). The diameter of the rotor is very slightly less than the inside diameter of the metering chamber, and its speed of rotation is proportional to the volumetric flow rate. It consists of a multi-bladed rotor mounted at right angles to the fluid flow and suspended in the fluid stream on a free-running bearing. Invented by Reinhard Woltman in the 18th century, the turbine flow meter is reliable for use with both liquids and gases.
Turbine flow meters are a type of velocity flow meter that have found widespread use in a variety of industrial applications – including aerospace, cryogenic, and custody transfer – for high accuracy measurements.
