What are the types of ultrasonic flow meters ? How it works?

denizen · January 21, 2017, 5:59am

Type of Ultrasonic meter are

1.Ultrasonic transit time 2.Ultrasonic doppler 3.Ultrasonic open channel.

How ultrasonic transit time flow meter works?

Transit time flow meter utilize two transducers which function as both ultrasonic transmitter and receiver.They operate by alternatively transmitting and receiving a frequency modulated burst of sound energy between the two transducers.

The burst is first transmitted in the direction of fluid flow and then against fluid flow.Since sound energy in a moving liquid is carried faster when travels in the direction of fluid flow (downstream) than it does when it travels against fluid flow (upstream),a differential in the times of flight will occur.

The sound’s time of flight is accurately measured in both directions and the difference in time of flight calculated.

Ultrasonic Doppler

The doppler meter continuously transmits high frequency sound that travels the pipe wall and into the flowing liquid.

Sound is reflected back to the sensor from solids or bubbles in the fluid.If the fluid is in motion the echoes return at an altered frequency proportionate to flow velocity.

Doppler flow meter continuously measure this frequency shift to calculate the flow.

Open Channel Theory

Using ultrasonic level technology open channel flow meter include a non-contacting sensor mounted above the flume or weir.By measuring the time from transmission of an ultrasonic pulse to receipt of an echo ,the water level or head is accurately measured.

To know more about Magnetic flowmeter

ARTang · May 17, 2025, 1:11pm

Types of Ultrasonic Flow Meters Ultrasonic flow meters are generally categorized into two main types based on how they measure flow:

Transit-Time Ultrasonic Flow Meters (also called Time-of-Flight) How it works: Measure the time difference between ultrasonic signals sent with and against the flow direction. Best for: Clean or slightly contaminated liquids with low particle or bubble content. Subtypes: Clamp-on (non-intrusive, mounted on outside of pipe) Inline (transducers embedded in the flow tube) Insertion (probes inserted into the pipe wall)
Doppler Ultrasonic Flow Meters How it works: Measure frequency shift (Doppler effect) of ultrasound reflected off particles or bubbles in the fluid. Best for: Dirty or aerated liquids containing suspended solids or gas bubbles (e.g., wastewater, slurries). Usually clamp-on or insertion types. How Ultrasonic Flow Meters Work (Basic Principle) Transducers emit ultrasonic pulses through the fluid. In transit-time meters, two transducers send and receive signals both upstream and downstream. The signal travels faster with the flow and slower against the flow. The time difference is used to calculate flow velocity. In Doppler meters, an ultrasonic signal bounces off particles or bubbles in the fluid. The change in frequency of the reflected wave is related to the flow velocity. The flow velocity is multiplied by the pipe’s cross-sectional area to get volumetric flow rate.