What are flow measurement devices and how do they work?

Flow measurement is a critical process for controlling fluids across a wide range of industrial applications. The flow of a fluid – which constitutes a liquid or gas – can be measured using a variety of different flow measurement devices. In this article, PIF spoke to fluid control experts Bürkert to find out more about their extensive range of flowmeters.

What is flow measurement?

Flow measurement involves measuring the flow rate and volume of a liquid or gas. It is used to monitor and control the rate of liquid flow in everything from light gases to heavy oils and aggressive chemicals. Flow measurement is heavily dependent on flowmeters to ensure safe, efficient and profitable flow processes.

A brief history of flow measurement

When we speak of flow measurement devices, the critical component that springs to mind is the flowmeter. Humans have been using flowmeters in some form or another for thousands of years, dating back to ancient civilisations like the Mesopotamians and Egyptians. Their early flow measurement systems enabled them to channel river water into plumbing systems and predict their water supplies in advance.

It wasn’t until the eighteenth century that any new breakthroughs in fluid mechanics were made, thanks to the fluidic theories of Swiss mathematicians Daniel Bernoulli and Leonhard Euhler. Arguably though, it was the nineteenth century that witnessed the greatest advancements in flow measurement, with the discoveries of Michael Faraday, Christian Doppler and Gaspard Coriolis all giving rise to flowmeters inspired by their ideas.

Modern flowmeters from Bürkert

The principles of those great minds of the nineteenth century are still employed in various flowmeters today. But further advancements in technology have also expanded the capabilities of modern flowmeters. Take Bürkert’s Type 8098 FLOWave flowmeter, for example. This innovative flowmeter uses the same surface acoustic waves used to detect seismic activity to provide highly accurate, non-contact flow measurements.

As well as the completely unique FLOWave, Bürkert also offers a comprehensive selection of flowmeters to suit all manner of fluid control applications. Their impressive range covers everything from differential pressure flowmeters to electromagnetic flowmeters and ultrasonic flowmeters. But, for the purposes of this article, we’re going to explain the working principles of three of their main types of flowmeters.

Oval gear flowmeters

Oval gear flowmeters employ positive displacement technology to measure the volume of fluid passing through the flowmeter. They do this by entrapping fluid in rotating parts to measure its flow. The more fluid that flows, the faster the rotating parts turn. The transmitter fundamentally determines the flow of fluid by processing the signal generated by the rotation. Oval gear flowmeters deliver a high degree of accuracy.

Paddle wheel flowmeters

Paddle wheel flowmeters comprise a paddle wheel sensor, pipe fitting and a display. The sensor is made up of a rotating impeller with embedded magnets. This is perpendicular to the flow and rotates when inserted into the fluid. As the magnets spin past the sensor, the flowmeter generates a frequency and voltage signal proportional to the flow rate. The faster the flow, the higher the frequency and voltage output.

Thermal Mass Flow Meters

Thermal mass flow meters measure the mass flow rate of a fluid through a tube. They do this by either maintaining a probe at a constant temperature and measuring the energy that requires or introduce heat into the flowing stream and measure any associated temperature change. Bürkert also supplies mass flow controllers that include a proportional control solenoid valve and control electronics to modulate flow.

For more information, please contact Bürkert today.