Swirl Flowmeters are exceptionally good at measuring steam, gases and liquids. They are similar to vortex meters but require much lesser straight runs and provide improved accuracy.
The inlet pipe converts the axial flow of the incoming measuring medium into rotational movement. In the center of this rotation a vortex core is formed which is forced into a secondary spiral-shaped rotation by the backflow. The frequency of this secondary rotation is proportional to the flow and, if the internal geometry of the meter measuring device exhibits an optimum design, will be linear over a wide measuring range. This frequency is measured by a Piezo sensor. The frequency signal from the flowmeter sensor, which is proportional to the flow, undergoes downstream processing in the transmitter.
ABB has 2 variants of Swirl flowmeters.
The FSS430 Swirl Flowmeter
The FSS430 Swirl flowmeter is for vapor, liquid and gas, with optional graphical display, optional binary output and optional integrated temperature measurement.
The FSS450 Swirl Flowmeter
The FSS450 Swirl flowmeter for vapor, liquid, and gas, with integrated digital output, temperature compensation and flow computer functionality. The device offers the option of directly connecting external temperature transmitters, pressure transmitters, or gas analyzers.