Dual-rotor flow turbine meters offer superior accuracy

Jon Lawson

Turbine flow meters have been a recognised and reliable form of measurement technology for many years.The volumetric flow rate is calculated using the rotational velocity of the turbines rotor. When the flow of liquid or gas increases, the rotor inside spins faster, which is directly linked to the volumetric flow.

Dual-rotor configuration meters are being used more regularly in industry now than in past years. This is due to their higher accuracy, large turndown ratios and improved repeatability. Research has shown that a dual rotor is far superior to a traditional single rotor in all these performance categories. Badger Meter’s Cox Exact Series, available from Bell Flow Systems, uses dual-rotor technology and is extremely versatile.

This series of flow turbines can be employed in numerous applications across various industries. Application examples include automotive and industrial applications such as engine test cells, precision blending processes, and F1 set-up and testing.

The turndown ratio of the Cox Exact Series is far greater than the typical 10:1 and can be as high as 500:1. This allows lower flows to be measured more precisely at greater than 0.15% accuracy of reading with repeatability down to ±0.02% on request, which can benefit a business economically by having one highly efficient dual-rotor meter rather than several single rotor meters. This range is constructed from 316 stainless steel and is suitable for harsh environments and high pressures up to 210 Bar.

Another benefit is that neither straight sections of pipe or flow straighteners are required during installation, allowing the meters to be located almost anywhere in a piped system. The Cox Exact Series incorporates a helical rotor design that allows for a reduced pressure drop and less bearing wear. The force of the flow is evenly distributed across the rotors and bearings, which not only reduces the bearing wear but also improves repeatability and ensures longevity of the meter in service.