Ultrasonic Flow Meters – Types and Applications

Ultrasonic Flow Meters - Types and Applications

Types of Ultrasonic Flow Meters with Applications

Some types of flow meters electromagnetic flow meter manufacturer in India supply are: differential pressure flow meter, volumetric flow meter, electromagnetic flow meter, turbine flow meter, ultrasonic flow meter, etc.

Ultrasonic Flow Meter

Sending ultrasonic waves through a pipe that contains the flow in both the direction of the flow and the opposing movement allows an ultrasonic flow meter to measure the flow of a liquid or gas. The flow rate may be calculated by combining the ultrasonic waves and the liquid or gas flow velocity. With two transmitters and two receivers, one on either side of the pipe at a specific distance, an ultrasonic flow meter can produce precise measurements.

With an accuracy rating of 1%, ultrasonic flow meters are crucial for custody changes. The clamp-on variant attaches to the outside of a pipe without being obtrusive and is simple to install. Ultrasonic flow meters are adaptable, bidirectional, and free of moving components in contrast to other types of flow meters.

Ultrasonic Doppler Flow Meter

An ultrasonic Doppler flowmeter typically comprises a transducer and a transmitter, indicator, or totalizer. Depending on the application, the user chooses a configuration that takes into consideration the liquid, the size and concentration of particulates or bubbles, the dimensions of the pipe, and the pipe lining. The signal threshold of the transmitter often changes to remove mechanical and electrical noise.

Working of Doppler Flow Meter

The transducer, which attaches to the outside of the pipe in the well-known clamp-on configuration, is driven by a high-frequency oscillator in the transmitter. The transmitter turns the discrepancy in frequency between the transducer’s output and input frequencies into electrical pulses that go through the pipe wall and into the flowing liquid. The pulses give a measurement of flow once they have been transformed, scaled, and totalized.

A clamp-on ultrasonic Doppler flowmeter works non-intrusively and without any moving components. They have low maintenance requirements, little pressure drop, and no risk of process liquid damage. They can be calibrated to have an accuracy of 1%, but signal interference can be caused by the pipe wall and any air between the wall and the liquid.

Additionally, the transmitted signal may be conducted by a stainless-steel pipe wall to the point where the reflected signal appears to undergo a significant change.

Ultrasonic flow meters that measure transit time track how long it takes an ultrasonic signal to travel from the first transducer to the second before being picked up. Measurements taken upstream and downstream are compared differentially. The journey time will be the same in both directions if there is no flow.

When flow is present, sound flows more quickly when flowing in the same direction as it does more slowly when moving the opposite way. The ultrasonic flow meter’s Doppler frequency shift, caused by fluid particulate matter scattering sound waves, is what the device detects.

The frequency shift tells us how fast the fluid is moving. The flow of waste material, water, and other open-channel liquids may be measured in open channels using an ultrasonic flow meter in the Doppler form.

Doppler Effect

The Doppler Effect, which occurs when an ultrasonic signal is reflected by moving discontinuities like gas bubbles or suspended particles, is the core working concept. The scientific phenomena of a sound wave changing frequency, when it is reflected by moving discontinuities in a flowing liquid, is used in this metering approach. When ultrasonic sound is sent through a pipe filled with flowing liquids, the discontinuities reflect the sound wave at a slightly different frequency that is inversely proportional to the liquid’s flow velocity.

Ultrasonic Transit Flow Meter

Ultrasonic flow meters that use transit time determine the rate of flow by timing the passage of ultrasonic pulses through the fluid. The flow rate is then calculated from the received rate of the ultrasonic pulses. The capacity of transit time ultrasonic flow meters to measure the flow rate independently of the flow direction distinguishes them from other types of flow meters.

Ultrasonic Flow Meters Applications

Ultrasonic flow meters are used for open channel water measurement and water flow through pipes. They are ideal for oil extraction and production, as they do not have to be installed inside the pipe, making them easy to install and time-saving. Ultrasonic flow meters are useful for oil wells, refineries and distributors.

In pharmaceutical labs, flow rates are measured with biopharmaceutical ultrasonic flow meters. They are media contact-free clamp-on flow meters that can be attached to flexible tubes. Despite being a crucial physiological parameter, blood flow is challenging to measure. 

The echo signal from erythrocytes in the blood serves as the foundation for the operation of an ultrasonic blood flow meter. The dispersed wave’s frequency shift gives a visual representation of the scatterers’ velocities.

The magnitude and direction of the flow velocity are determined using the Doppler shift. The ultrasound signal is pulsed to make sure that the Doppler shift data are accurate. By range gating the return signal, the diameter and velocity of the bloodstream can be measured.