subject: Ultrasonic Flow Meters: The Best Flow Measurement Instrument For Your Application. [print this page] Ultrasonic flow meters can be used for measuring the flow of both gases and liquids. There are several types of measurement technologies that flow meters work on. The most popular types include transit flow meters, which are suitable for both gases and liquids. They are the most inexpensive and simplest of the ultrasonic technologies as they simply measure the time lapse between a pulse sent in the direction of the flow and one that is sent opposite to the flow. This gives a measure of the flow.
The ultrasonic flow meter - A glance
An ultrasound flow meter essentially consists of two transducers that can emit and receive ultrasound. The setup involves installing these two transducers around a pipe. Hence there is no disturbance to the existing setup of the pipeline. When one of the transducers emits, the other receives. The time lag and frequency shift are parameters measured of the received sound wave. These changes are proportional to the flow rate and are then given as a measurement by the output transducer.
Scope For Continuous Measurements
The main reason why ultrasound flow meters are chosen over other technology flow meters is the scope to continuously monitor flow, as against just an average value, unlike devices based on most other technologies. A continuous measurement in real time is more desirable than an average value, as continuous measurement is more representative of what is actually happening in the fluid. Continuous measurement is also necessary in most applications
Can Be Used For Non Conducting Fluids
While most techniques employ technology that banks on the electrical or magnetic conductivity of the fluid being measured, ultrasonic techniques employ sound. The conductivity of sound does not require the fluid to have any electric and magnetic properties. Though the measurement can be affected by changes in temperatures and pressure, the correction is most often very simple to make. The devices itself can be calibrated for such changes. Hence there is scope for measuring the flow of any kind of fluid with a high degree of accuracy.
Wide Range and high Cost to Performance Ratio
Ultrasonic flow meters offer a wide range of measurements. In flow meter parlance this means a high turndown ratio. The cost of the flow meter is determined by the range of measurements it provides. For every increase in this ratio, the cost goes up. In terms of price increase, for an increase in the turndown ratio ultrasound flow meters gives the best value when compared to any other technology.
