How do ultrasonic flow meters work?
An external clamp-on ultrasonic flowmeter is employed for measuring the flow rate of liquid or gaseous fluids
The properties of the fluid flow and the substance being measured will dictate or impact the choice of an appropriate and precise ultrasonic measurement method
When ultrasonic waves meet different things, they can pass through, spread out, or become weaker
Lấy ví dụ như sóng siêu âm thường sẽ đi xuyên qua không khí dễ dàng và khi gặp bề mặt rắn sẽ phản xạ đến 99% tín hiệu sóng.
Based on wave transmission principles and material theories, there are two widely researched and applied ultrasonic measurement principles:
Transit Time Measurement Principle
The Transit Time measurement principle operates by measuring the time taken for an ultrasonic wave to travel from the transmitter to the receiver, passing through the pipe wall and the fluid inside
As the fluid flows, the transit time of the ultrasonic wave changes. The device can calculate the flow velocity by comparing the transit times in opposite directions.
- When the flow opposes the direction of the ultrasonic wave, the wave’s speed decreases, leading to a longer travel time.
- When the flow moves in the same direction as the ultrasonic wave, the wave’s speed increases, resulting in a shorter travel time.
Applications: Transit Time is typically more accurate in applications with clean flow, free from many particles or air bubbles, and is commonly used in industrial applications, clean water systems, and HVAC systems.
Noisetrek Measurement Principle (Doppler Effect)
The NoiseTrek (Doppler effect) measurement principle is based on the change in frequency of ultrasonic waves when they are reflected from solid particles or gas bubbles within the flow.
As the liquid flows, carrying solid particles, the frequency of the reflected ultrasonic wave changes depending on the flow velocity.
Applications: Noisetrek is more suitable for flows containing particles or air bubbles, making it ideal for applications in the oil and gas industry, wastewater, and media containing impurities.
Integrated Solution and Automatic Switching Between the Two Measurement Principles in Flexim Flow Meters
The Fluxus F721 Series (Flexim – Emerson) integrates both Transit Time and NoiseTrek (Doppler Effect) measurement principles. By automatically switching between these two measurement methods, the Fluxus F721 offers versatile flow measurement capabilities for a wide range of fluids, from clean liquids to those containing impurities or gas bubbles
- Excellent adaptability: Capable of handling various flow conditions, including clean water, wastewater, and flows with high levels of contaminants or up to 10% suspended solids
- High reliability: Automatic switching between the two principles allows the device to achieve high accuracy and reliability in various flow conditions and helps detect anomalies if they occur during operation.
With these superior features, the Flexim F532/F721 series is the ideal choice for clamp-on ultrasonic flow measurement applications, ensuring high accuracy and reliability in all operating conditions.
Contact us today to learn more about the Flexim solution and optimize your investment costs!
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Prepared by: Phan Tan Phat - BDM Flexim
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