CHAPTER 14 - MEASUREMENTS IN PRESSURE CONDUITS
The vortex generating flowmeter is based on the principle that obstructions placed in flows generate vortex shedding trails in the flow (White and McMurtrie, 1971). A properly shaped obstruction will produce stable vortices that reinforce or interact with each other on each side of the obstruction.
The shedding vortex oscillations are sensed in different ways such as by thermistors, pressure cells, or magnetically picking up the oscillation of a shuttle ball in a chamber that has each end connected to each side of the obstruction. The proper shape of the obstruction also produces an oscillation frequency that is proportional to velocity over a large range of flow.
Manufacturers cite advantages such as the possibility of no moving parts, calibration by dimensional tolerance limits to +1 percent, large discharge range, and adaptability to electronic digital counting. The meters can be made portable by installing the obstruction through the stuffing boxes.