Ultrasonic Flow Meters

Ultrasonic Flow Meters

Ultrasonic flow meters are flow meters that use sound to determine flow rate. A few ultrasonic flow meter varieties include Doppler Effect flow meters and time-of-flight flow meters. An ultrasonic flow meter is a volumetric flow meter which requires particulates or bubbles in the flow. Ultrasonic flow meters are available in both single and dual-sensor versions. The basic principle of operation employs the frequency shift (Doppler Effect) of an ultrasonic signal when it is reflected by discontinuities, in the form of suspended particles or bubbles, in motion. Ultrasonic sound is transmitted into a pipe with flowing liquids, and the discontinuities reflect the ultrasonic wave with a slightly different frequency that is directly proportional to the rate of flow of the liquid. This process allows the meter to get an accurate measure of the liquid’s flow rate.

Ultrasonic flow meters are ideal for wastewater applications or any dirty liquids that are conductive or water-based. Ultrasonic flow meters are also ideal in situations where low pressure drop, chemical compatibility, and low maintenance are required. However, ultrasonic flow meters will generally not work with distilled water or drinking water. Important considerations to keep in mind while choosing an ultrasonic flow meter include the size of the pipe, the minimum/maximum flow rate required, and the minimum/maximum process temperature and pressure needed. Also, determining whether a handheld or continuous process monitor is needed is also important. The addition of an analog output is another possible consideration.

Ultrasonic Flow Meters Image Provided by KOBOLD Instruments Inc.	Ultrasonic Flow Meters Image Provided by Burkert Fluid Control Systems