PRACTICAL OPTIONS FOR ON-LINE FLOW MEASUREMENT.

Flow, along with temperature, pressure and level, is one of the four most commonly measured parameters in the process industries. The scope of flow measurement is extremely broad, covering extremes of high and low flow rates, temperature and pressure, and fluid conditions from clean non-viscous liquids to viscous two and three-phase fluids, and various solids flows. As a consequence of the scope of flow measurement there are a large number of measuring devices available on the market and the potential user is faced with a bewildering choice. Here, the operating principles of some commercially available techniques are outlined with emphasis on more recent developments, their advantages and limitations.