ABSTRACT
The working principle of differential pressure flow meters based on the equation of continuity and Bernoulli's equation in which a restriction in the flow line creates a pressure drop that bears a relationship to the flow rate is examined in this chapter.
An in-depth discussion on the orifice plate is provided looking at how the measurement accuracy is compromised due to a wide number of factors including plate contamination, warped plates, reversed plates, worn-leading edge, plate misalignment, blocked impulse tubes, and saturated transmitter.
A close look is also taken at a variety of special orifice plate assemblies and installation configurations. This is followed by further examination of the merits and demerits of the orifice plate in general.
Other technologies explored include: segmental wedge meter, V-cone meter, Venturi tube meter, Venturi nozzle meter, Dall tube, multiport point averaging meters, and variable area meters.
After examining a variety of piping arrangements the chapter concludes with a method of plugged impulse tube detection.
