All About Ultrasonic Flow Meters

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  • Post last modified:April 29, 2023

An ultrasonic flow meter is undoubtedly the best option for measuring the velocity of a fluid with ultrasound to analyze the volume flow. As a volumetric flow meter, the main principle behind its working is its usage of sound waves (through ultrasonic transducers) to measure the flow. 

The first ultrasonic flow meter, invented in 1959 by Shiego Satomura, used Doppler technology to deliver the analysis of blood flow. After four years, in 1963, the instrument began to be used for industrial applications. In today’s time, many manufacturing companies design different types of clamp-on flow meters with ultrasonic transducers to determine the fluid velocity and flow rate. 

Its construction requires upstream and downstream transducers, a sensor pipe, and a reflector. These meters can be attached to the inside or the outside of a pipe. When the meter is activated, ultrasonic waves are transmitted from one side of the meter to the other, which are then collected and measured to determine the liquid flow. 

There are multiple types of flow meters that differ only in their “way” of working, but they all operate on the same principle. In the transit-time flow meter, ultrasonic waves are sent in opposite directions (one upstream and one downstream) and the flow is measured by calculating the time difference taken for these two signals to reach the opposite side. On the other hand, the Doppler type flow meter makes use of the Doppler effect by transmitting a sound wave through the liquid and measuring the reflection of the wave. While the former is efficient in measuring clean liquids, the latter can be used to measure liquids with impurities and particulates. 

It’s no surprise that ultrasonic flow meters are ideal for a lot of purposes, but they still have their drawbacks. If you’re exploring flow meter options, it is important to understand the advantages and disadvantages of this instrument and see if it will suit your requirements. 

Advantages Of Ultrasonic Flow Meter: 

  1. It prevents blockage of the path of liquid flow and allows for the bidirectional flow of liquid. 
  2. The output can be obtained in digital or analog format, with easy access to measurements in real time to a central monitoring system. 
  3. It has low power consumption, which makes it last a long time before the batteries need to be replaced.
  4. It is suitable for high quality flow measurement with high levels of accuracy. 
  5. They are usually inexpensive to maintain because they do not require any moving parts. 
  6. There is no leakage risk, no moving parts, and no pressure drop. 

Disadvantages Of Ultrasonic Flow Meter: 

  1. The upfront cost is high in comparison to other mechanical flow meters because of the high cost of acoustic parts.
  2. They are complicated in design and require specialized maintenance and repair. 
  3. Clamp-on ultrasonic flow meters cannot measure cement/concrete pipe or pipes which have a lining of such materials. 
  4. They cannot be used for liquids that are heavily contaminated. 
  5. Any type of liquid that doesn’t allow for ultrasonic energy to pass through cannot be measured through an ultrasonic flow meter. 

Its advantages over its disadvantages make it ideal for usage in several industrial applications, such as oil, gas, pharmaceutical, food and beverage, metal, mining, pulp and paper, and wastewater industries. In any case, if the application benefits from a flow measurement technique that is non-invasive and long-lasting, ultrasonic flow meters are a perfect fit!