Custody transfer flow measurement in water distribution network

Evides Waterbedrijf N.V., one the largest water companies in the Netherlands ordered Visser, Smit and Hanab to build a drinking water pipeline from De Staart in Dordrecht, the peninsula where also KROHNE Altometer is located, to Zwijndrecht. Visser & Smit Hanab develops, builds and maintains connections, networks and installations for water and energy. Evides sells so-called soft water to another Dutch water company, as part of a project to solve the hard-water problem of Zwijndrecht. For the transport of the potable water, a new pipeline was needed between the distribution networks of the two water companies. The building of the pipe was not an easy task as it runs trough a densely populated area and it crosses the very busy river Merwede. Over a length of 1450 m / 0.9 m the pipe has been installed at a depth of 26 m / 85.3 ft under the river.

Accuracy has been an important selection criterion for selecting a flowmeter, because it concerns the custody transfer of potable water between two companies. The flow measurement is subject to fiscal regulations and therefore requires a certification according to the Measuring Instruments Directive 2004 / 22 / EC MI-001 for water meters.

At the location of installation there is no mains power available, so a battery powered, stand alone, water meter was preferred. Other requirements of the customer for the water meter included the availability of approvals for drinking water, protection against submersion in water (IP 68), and a high turndown ratio. The maximum flow rate in the pipe is 650 m³/ 171,711 US gal per hour.

“Our partner KROHNE, with whom we already have a good cooperation for many years, has developed a new product that met our needs”, says Werner Boom, Business Change Manager Metering of Evides. “We have decided to install the WATERFLUX, because the KROHNE products have a high degree of reliability and this new meter completely fitted our needs and demands. This flow meter does not require an external power supply; the battery provides enough power for 15 years, and the data transfer takes place via a GSM module. The rectangular design provides a unique homogeneous magnetic field. This ensures a high accuracy within the measurement range and virtually has no pressure loss. It is an innovative and durable meter with a high degree of reliability."