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Currently, the ultrasonic clamp-on flow meter market is valued at USD 942.2 million and estimates a projected CAGR of 7.8% by surpassing USD 1,986.4 million by 2032.

With technological improvements, ultrasonic clamp-on flow meters have become a hit in the market, specifically because of their fundamental feature of measuring the flow without disturbing the flow stream. 

Additionally, the rising emphasis on energy and water conservation has led to an increased demand for ultrasonic clamp-on flow meters. Owing to their adaptability, significance, accuracy, and non-intrusiveness, their market is expected to rise steadily.

Let’s understand how and why!

What is an Ultrasonic Inline Flow Meter?

The flow rate of liquids within the pipe is measured with the help of an ultrasonic inline flow meter. It is called an ultrasonic inline flow meter because of the ultrasonic technology employed inside to accurately regulate the velocity of the liquid passing through the pipe

Directly installed into the pipeline, an ultrasonic inline flow meter allows continuous and non-intrusive measurement of the flow that is highly reliable and suitable for a wide range of applications like industrial processes, water treatment, HVAC systems, and more.

Recommended Read: Ultrasonic Flow Meter - Types, Applications, Working & More

Ultrasonic Inline Flow Meter Technology

Ultrasonic flow meters work by sending ultrasonic pulses throughout the fluid along with measuring the time these pulses take to travel upstream and downstream.

For instance, an ultrasonic flow meter is installed in a water pipe in a residential building to measure the flow rate passing through it. 

The ultrasonic flow meter will emit ultrasonic pulses from one side of the pipe to another and detect the pulses on the opposite sides.

So, by measuring the time taken by the pulses to move downstream and upstream, the ultrasonic flow meter calculates the water flow velocity.

Recommended Read: All You Need To Know About Different Types Of Flow Meters

How Calibration is Done in Ultrasonic Flow Meters Using Different Methods? 

The selection of calibration method depends on factors like available resources, accuracy measurements and the specific application of the flow meter. Let’s find out how calibration is done using different approaches. 

Calibration Method


Gravimetric Method 

The process includes passing a known volume of fluid through the ultrasonic flow meter and collecting it in a vessel placed on a precision balance. The mass of this collected fluid is then measured, based on which the flow rate is calculated. This method is known for providing highly accurate calibration because it directly measures the mass flow rate. 

Comparison Method 

Here, the flow rates are measured under identical conditions to note the discrepancies. Later, corrections are applied to the readings of the test meter based on the deviations noted in the comparisons. 

Volume Comparison Method 

In this method, the volume of the fluid passing is compared with a calibrated reference standard. Under test and reference standards, a known volume of the fluid is passed through ultrasonic flow meters to compare and record any deviations. Later, corrections are applied to the readings of the test meter based on differences observed from the comparison. This method is the most suitable in lab settings.

Transit Time Comparison Method

Under this, ultrasonic signals are transmitted between the transducers on the opposite sides and the transit time is measured by the test meter which is later compared to those of the calibrated reference, correcting all the differences for accurate flow measurement. This method is suitable for calibrating transit-time ultrasonic flow meters.

Recommended Read: Top 9 Water Measurement Essentials Explained

Ultrasonic Flow Meter Calibration Tips

The calibration of an ultrasonic flow meter is important for regulatory compliance, ensuring reliable measurements, data integrity, and optimized performance.

Below are the key points to keep in mind while calibrating an ultrasonic flow meter:

  • Adhere to the manufacturer’s guidelines. For instance, if you’re buying from Kritsnam you’ll be provided with the instructions and calibration processes to make the process easier.
  • Plan calibration sessions with NABL-accredited laboratories like Kritsnam for accurate and traceable results.
  • Consistent environmental conditions must be maintained to mirror operational conditions during the calibration process. 
  • Make sure that you calibrate across the entire flow range to maintain accuracy within all flow rates. 
  • Proper transducer alignment is important for reliable measurements.
  • Keep detailed records of results for future reference. 
  • To ensure accuracy at the lowest flow rates, opt for zero flow calibration. 

Once the calibration process is over, verify the results to secure compliance with accuracy specifications.

Recommended Read: The Ultimate Guide To Flow Meter Installation For Best Accuracy

What is an Ultrasonic Clamp-on Flow Meter?

Simply put, an ultrasonic clamp-on flow meter is a device or an instrument that measures how quickly the liquid flows through the pipe with the help of sound waves (ultrasound) to identify the speed of the liquid.

The special part of this meter is that it is attached to the outside of the pipe using a clamp to maintain the flow inside the pipe.

Recommended Read: What happens when there is partial flow in a pipe?

Ultrasonic Clamp-on Flow Meter Technology

Without physically touching the fluid, ultrasonic clamp-on flow meters utilize the sound waves to measure the liquid flow velocity.

Let’s take an example of a water distribution system. Here the meter can be clamped outside to measure rate without any interruptions in the water flow. 

The meter will calculate the flow velocity with the help of ultrasonic pulses moving upstream and downstream.

Thus, it can be concluded that ultrasonic clamp-on flow meters work in a non-intrusive way which makes them suitable for a wide range of applications and industries.

How to Install an Ultrasonic Clamp-On Flow Meter?

Here’s how you can install an ultrasonic flow meter in a few simple steps:

  • Select where you want to mount the flow meter on the pipe. 
  • Clean any dirt or debris on the pipe as it affects the performance.
  • With proper alignment and spacing, mount the ultrasonic flow meter outside the pipe. For instance, in a water treatment plant, the flow meter is installed on the main water supply line.
  • Now, connect the transducers to the flow meter’s electronic module as per the manufacturer’s guidelines. 
  • Perform tests to verify performance and functionality.
  • Seal the gaps to prevent moisture and protect the flow meter from environmental factors.
  • Regularly monitor and maintain the flow meter for consistent accuracy and reliability. 

Benefits of Using Clamp-on Flow Meters

Selecting a flow meter to add to an existing plumbing network is daunting. A lot of factors like accurate flow measurement, balance, replacement, and other risks add to the flow meter installation process.

With increased focus on water reduction programs, many companies are opting for ultrasonic clamp-on flow meters. The advantages of ultrasonic clamp-on technology are listed below:

  • Non-Intrusive Installation: Mounted outside the pipe, preventing operational disruption and reducing downtime and maintenance costs.
  • Versatility: Suitable for various pipe materials and sizes, e.g., PVC, HDPE, and steel.
  • Durability: Minimal wear and tear due to no contact with the fluid.
  • High Reliability and Accuracy: Non-intrusive nature ensures precise flow rate data without affecting system integrity or water quality.
  • Repositioning Flexibility: Easily relocated, ideal for applications like irrigation systems. 

Recommended Read: Different Methods To Validate The Accuracy Of Flow Meter On The Field

Applications of Clamp-on Flow Meters

Without the need for pipe modification, ultrasonic clamp-on flow meters can be used across a variety of applications.

  • Wastewater Management: Monitors sewage flow rates in sewer lines for efficient treatment.
  • HVAC Systems: Measures heating fluid or chilled water flow to optimize energy use.
  • Industrial Processes: Provides accurate flow measurements for chemical manufacturing and process control.
  • Water Distribution Networks: Tracks water usage and detects pipeline leaks for efficient management.

Best Practices for Clamp-on Flow Metering

Users can optimize the reliability and performance of clamp-on flow meters by adhering to the best practices given below:

  • Choose the right ultrasonic clamp-on flow meter for its non-invasive installation, accuracy, reliability, versatility, and low maintenance, suitable for diverse industry applications.
  • Opt for suitable pipe material which is conducive to ultrasonic wave transmission. It might be metal or plastic.
  • Remove any rust, debris or corrosion on the pipe surface as there’s a high chance that the dirt particles might interfere with the process.
  • In turbulent flow conditions, monitor the flow profile and pipe conditions for accurate measurement. 
  • Regular checks and comparisons must be conducted to validate the accuracy and verify results from the ultrasonic clamp-on flow meter.

Ultrasonic Clamp-on VS Inline Flow Meters

Ultrasonic vs. Inline Flow Meters: Key Points

Ultrasonic Flow Meters (UT):

  • Measure liquids and gases accurately without pressure drop, drift, or obstruction.
  • No moving parts, low maintenance, and suitable for extreme temperatures.
  • Operate non-intrusively outside the pipe using the ‘differential transit time’ method.

Inline Flow Meters:

  • Provide direct contact with the fluid for higher credibility and accuracy.
  • Ideal for high-pressure or high-temperature environments.
  • Offer various options like Coriolis, electromagnetic, turbine, etc., for flexibility and versatility in measurement techniques.

In summary, ultrasonic clamp-on flow meters offer easy retrofitting and non-invasive installation, while inline flow meters excel in accuracy and suitability for industrial applications requiring precise fluid contact and measurement.

Dhaara - A Smart Choice For A Wise Water Revolution

Water intelligence has taken the front seat in reshaping water for a secure future with water budgeting applications for businesses to eliminate water risks and digitally manage their water footprint.

However, selecting the right clamp-on flow meter depends on the type of application you’re using it for. 

With Dhaara Smart from Kritsnam in the market, most companies are opting for these inline USFM meters because of the quick and non-intrusive installation process, reduced maintenance, versatility and high accuracy. 

Dhaara Smart
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Dhaara Smart
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The Dhaara is a new-age water meter that combines the power of IoT with the latest sensor technologies. The integrated telemetry and battery-powered capabilities make it easy to manage your water consumption from anywhere and anytime (even when the power is down).
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Dhaara Digital
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Dhaara Digital has been purpose-built to address the requirements of customers seeking metering solutions falling under the exemption category of CGWA (Central Ground Water Authority) compliance and other applications where telemetry is not required.
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