Best in Class Flow Measurement Accuracy
Rosemount Gas and Liquid Ultrasonic Flow Meters deliver high accuracy, wide rangeability, and advanced diagnostics—without moving parts—minimizing pressure loss and maximizing reliability. This proven technology supports a variety of applications, including custody transfer, allocation measurement, check metering, leak detection, and inventory control.
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Understanding Ultrasonic Flow Measurement
How Does a Rosemount™ Ultrasonic Flow Meter Work?
Rosemount™ ultrasonic flow meters measure liquid or gas flow using sound waves, analyzing how signals travel through a moving fluid. By comparing upstream and downstream transit times, they determine velocity and calculate flow rate. With no moving parts and no flow obstruction, they deliver accurate, reliable measurement with minimal maintenance and no pressure loss.
Rosemount™ Ultrasonic Flow Meter Videos
Explore Rosemount™ ultrasonic flow meter videos covering applications, products, and step-by-step guidance. Learn how to improve gas measurement accuracy, configure connectivity, review Smart Meter Verification results, and perform maintenance tasks. These videos provide practical insights to support setup, troubleshooting, and reliable operation.
Improve Natural Gas Measurement Accuracy with Rosemount Ultrasonic 3410 Series Flow Meters
Improve Natural Gas Measurement Accuracy with Rosemount Ultrasonic 3410 Series Flow Meters
Rosemount T-200 Gas Ultrasonic Transducer
Rosemount 3418 8-Path Gas Ultrasonic Flow Meter
How to Connect a Rosemount 3410/3810 Series Ultrasonic Flow Meter Using an Ethernet Connection
How to Review Smart Meter Verification Reports and Create an On-demand Report on a Rosemount 3410 Series Ultrasonic Flow Meter
How to Replace an Intrinsically Safe (IS) Barrier Board on a Rosemount™ Ultrasonic Flow Meter
Explore Ultrasonic Flow Measurement Resources & Application Insights
Access expert content to support your flow measurement needs including case studies, white papers, brochures, and technical guides. Learn how ultrasonic technology improves accuracy, reliability, and performance across real-world applications and industries.
Frequently Asked Questions
Explore these frequently asked questions to learn how Rosemount™ Ultrasonic Flow Meters work.
An ultrasonic flow meter is a device that measures the flow rate of liquids or gases using high-frequency sound waves. Instead of relying on mechanical components, it determines flow by analyzing how ultrasonic signals travel through a moving fluid.
Because they have no moving parts and do not obstruct the flow path, ultrasonic flow meters provide accurate, reliable measurement with minimal maintenance and no pressure loss.
An ultrasonic flow meter measures flow by sending sound waves through a fluid and analyzing how flow affects those signals. Sensors transmit pulses with and against the flow. The meter calculates the difference in travel time to determine fluid velocity, then converts it to flow rate. Because it’s non-intrusive, the measurement is accurate without disturbing the process.
The working principle of ultrasonic flow measurement is based on how sound waves propagate through a moving fluid.
There are two primary measurement principles:
- Transit-Time (Time-of-Flight)
- Doppler Effect
Both methods rely on the same core concept:
Changes in ultrasonic signal behavior reveal how fast the fluid is moving. Rosemount™ Ultrasonic Flow Meters rely on Transit-Time for high accuracy custody transfer applications.
Ultrasonic flow meters calculate flow rate by first determining fluid velocity, then converting that into volumetric flow.
Flow rate = velocity × pipe area
Because ultrasonic measurement is based on acoustic properties rather than mechanical motion, it maintains high accuracy across a wide range of conditions.
In-line ultrasonic flow meters use the transit-time principle when high accuracy is needed:
- Two or more sensors send ultrasonic pulses in opposite directions across the pipe
- The pulse traveling downstream moves faster with the flow
- The pulse traveling upstream takes longer against the flow
- The meter measures this time difference to calculate flow velocity and volume
This method is ideal for gases, delivering highly accurate, repeatable measurements across a wide range of operating conditions.
In applications where fluids contain suspended particles or bubbles, ultrasonic meters may use the Doppler effect:
- A transmitted signal reflects off particles in the fluid
- The frequency shift of the returned signal indicates flow velocity
- This method is commonly used for slurries, wastewater, or aerated flows