Ultrasonic flow meters are a common phrase in most industrial applications. They have been used for years in manufacturing industries and are handy in measuring the flow rate of gases and liquids. Flow monitoring is vital in enhancing quality control, waste reduction, minimizing downtime, and helps save costs in most companies.
What are the principles of ultrasound flow measurements?
Ultrasound sound waves range from 25-100 KHZ and are the underlying principle in ultrasonic flow meters. An empty pipe doesn’t reflect the ultrasound frequency, and ultrasound reflection varies depending on the liquids of other elements used.
Ultrasonic flow meters are commonly used to determine flow measurements in fluids and gases and employ two types of technology. Do you want to find out more? These are the Doppler and transmit time meters.
- Doppler technology
- Transit time technology
1. Doppler technology
A Doppler flow meter changes the measure frequency shift to a volumetric flow rate. The Doppler method requires bubbles and particles in a fluid to reflect signals. Moreover, the transmitter signals reflect on the particles and bubbles in the liquid moving in the pipe. It then uses a slightly changed frequency to read the changes and determine the flow rate.
The flow in the pipe is also crucial and is determined using the frequency shift, speed of sound through the transmitter, and the sine angle at which it enters the liquid. Doppler flow meters are helpful for measuring wastewater, slurries, gases with sound reflecting particles, and bubbled liquids.
How do Doppler flow meters work?
Doppler flow meters determine the flow of a liquid or gas using the frequency on an ultrasonic beam. The device sends a signal reflected by the bubbles or particles, leading to a shift in frequency. The frequency shift is then measured by the flow meter.
2. Transit time technology
In this type of technology, the fluid in transit shouldn’t feature any particles or bubbles. There’s a maximum limit of bubble so particles that allow accurate measurements.
Transit time technology works on the propagation velocity of sound waves. These meters feature two sensors that convey and get signals simultaneously. When there’s no flow, there’s no transit time delay between the sensors.
Similarly, when there’s a liquid flowing in the pipe, the sensor will emit signals in the direction of the flow. And it will receive it faster than the one emitting the signal in the opposite direction. You can use the distance between the sensors to determine the flow velocity based on the time difference.
Ultrasonic flow meters- What are their applications?
Ultrasonic flow meters are useful in measuring the velocity of fluids and gases and are useful in a wide variety of applications. Some are portable, while others are clamp-on and are used in;
- Clean and wastewater delivery
- Oil and gas installations
- Steam pipes
- Gas detection
In summary, there are different types of ultrasonic flow meters and use the latest technology. The portable models are ideal for measuring temporary flows or verifying other meters. On the other hand, the clamp-on meters are non-intrusive but may not offer high levels of accuracy. Therefore, understand the process requirements or discuss this with the vendor before making purchases.