As it creates an electric charge through its interaction with the field, the charge is measured to find the speed of the flow. Orifice Plate - An orifice plate helps measures flow through the differences in pressure from the upstream side to the downstream side of a partially obstructed pipe. The plate offers a precisely measured obstruction that narrows the pipe and forces the flowing substance to constrict. The greater the flow, the greater the difference in pressure as the substance maintains its constricted state for a longer distance, passing the downstream element. Different kinds of orifice plates include concentric, eccentric, and segmental, each of which has different shapes and placements for measuring different processes.
Orifice plates are in common use in many installations.
Pitot Tubes - A bent tube with an open end that faces the flow, the pitot tube allows flow measurement by sensing how much of an impact the substance trapped in the tube causes. These sensing elements are often used in air ducts and airplanes. The measurements between several tubes can be averaged out for a more accurate overall reading. A float is forced upward by the flow, and the amount the float rises is measured to gauge the flow. As a substance moves through a pipe, it acts on the vanes on a turbine to get it to spin.