Low-flow liquid measurement solutions for industrial applications

Measuring liquids with a low flow rate is a necessity for many different industrial sectors, but the lower the flow – the harder it is to measure and control. Finding the right device, at the right price is not an easy task.

There is no specified definition of what constitutes a low flow rate, but amplified flow stability and performance issues are characteristics that are synonymous with these applications. Even the smallest of changes in ambient conditions can have a highly significant effect on stability and flow rate when there are low volumes of liquid being monitored. Flow meter specialists Titan Enterprises consider low flow rates to be less than 50 ml/min, but many of their customers seek instruments to measure flow rates of between 2 and 20 ml/min.

Neil Hannay, Senior R&D Engineer at Titan commented, “We are certainly seeing an increase in demand for low-flow measurement technologies driven by various industries moving towards transporting heavily concentrated liquids, which are then diluted at the point of use. This translates into huge savings on transport and storage costs and also has a positive environmental impact.”

Low-flow flowmeters are necessary to enable accurate dosing of concentrated fluids. At the end process, they must dispense the precise amount of liquid to the correct dilution in a host of demanding applications including cleaning fluid additives, syrups and flavourings for beverages, chemical additives for oil and fuel, or paint pigments.

As has already been stated, precise and reliable measurements of low-flow applications are challenging. The amount of energy available in low liquid flows is rarely sufficient to drive most mechanical flowmeters to provide linear results. However, electronic flow meters are often restricted by sensitivity, zero drift, and slow response times.

We now compare five different flow meter technologies: Ultrasonic, Turbine, Oval Gear, Thermal and Coriolis – and how suited they are for low-flow measurement applications -

Flowmeters are often the most limiting component of a low-flow fluidic system, so it is vital to choose the most suitable high-precision flow sensor for each different application.

“We know there is a strong market for low-flow meters, and we are currently working with two international OEMs to develop a solution for measuring ultra-low flows using our oval gear technology and miniaturised gears,” added Neil Hannay.