Working principle of Ultrasonic level measurement - Beam width type
What is beam width?
It essential to understand some important properties of sound. Sound travels from a source and its focused in a certain direction and as travels over a distance the wave spread from their source in a conical shape.These same physics applied to ultrasonic sensors.Here the path of the sound is called beam width.beam width is largely determined by the beam angle of the transducer which is typically 8 to 12 degrees on most ultrasonic sensors.Essentially the further the sound waves travel the wider the footprint becomes.Think a beam width as the minimum free space required for the unobstructed reliable level measurement but obstruction and obstacles do exist ultrasonic sensor should be located away from them whenever possible.Obstacle inside the beam path can disrupt the acoustic signal and can be detected as a liquid level .Ultrasonic flow meter consist of DSP (Digital signal processor ) .DSP will identify the obstacles and it will measure the actual level