Case study: EuroLoop: capacity thanks to closed loop system

For many years, capacity for calibrating industrial gas meters was in short supply. Long waiting times resulted due to the dependence of gas consumption in installations using a bypass. In order to serve customers all year round, NMi invested in a brand new and unique calibration facility for industrial gas meters. A clever innovation that is quickly gaining a reputation in the gas world.

NMi and VSL specialists got together to design this innovative calibration facility. Besides creating independence from the natural gas network, they faced challenging specifications with regard to pressure, flow and measurement uncertainties. Different design proposals, dozens of changes, creative solutions and ideal situations were discussed in the search for a realistic, feasible design that could fulfil the high expectations. How, for example, do you measure a gas flow in a 24 inch meter at a pressure of 60 bar at any time of the year? EuroLoop is the answer.

Closed loop system

A closed loop system was chosen for the advantages relating to measurement uncertainty and continuous availability of the installation. However, this also produced new challenges. Where do you put the gas if you want to test at low pressure or if you are changing meters and part of the system needs to be gas free?

The solution comes in the form of two enormous state-of-the-art gasholders, each with a volume of 3500 m³ and a pressure of 30 mbar. The entire contents of the installation can be stored, meaning that the same gas is used again and again without unnecessarily impacting on the environment.

Traceability and convertibility

The specialists at VSL developed a bootstrap method to make the high flow rates of EuroLoop traceable and convertible to the international standard (cubic metres of gas). Traceability and convertibility are built up using the very accurate reference gas volume, ultimately enabling measurements to be performed with great precision.

EuroLoop enables us to adjust our objectives for measurement uncertainties downwards.

Building an installation like EuroLoop is no sinecure, but on 24 March 2010, after years of design, construction and commissioning, all the parties involved were finally able to toast the launch of EuroLoop!

For more information visit www.nmi-euroloop.nl.