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The EESIFLO clamp on transit time flow meter is more universal by the fact that it does not require reflectors at all. Newer types of transit time meters cover most traditional clamp on flow applications because of improvements in the last decade in high speed electronics and sample filtering. This all means EESIFLO meters are able to measure both clean and dirty liquids.
The Portalok and Sonalok use employ two finely tuned sensors placed upstream and downstream external to any sonically conductive tube or pipe. The sensors are matched and carefully designed to work in situations where temperature variations exist since ultrasonic propagation is also a function of temperature.
An ultrasonic wave is sent both upstream and downstream (with and against the flow) to determine the time of flight or "transit time" which can be correlated to the average flow velocity.
If the fluid type is known, then a flow profile correction is calculated for each type of liquid being measured so that a different K factor can be used to report volume flow in either laminar or turbulent flow regimes. Advanced diagnostic functions assist the user in determining whether or not the installation was optimal. In almost every case, the set up can be done within minutes since the meters already contain a built in database of known liquids and their common properties.
In most cases the selection process is very simple i.e. choose a modern type transit time flow meter for clean and dirty liquids (Portalok and Sonalok) and only use Doppler meters when an extremely high amount of reflectors prevent even a small amount of signal passing from one side of the pipe to the other. EESIFLO manufactures both transit time and Doppler based meters
