Custody transfer filling of beer into kegs

An Austrian family-owned company specialises in keg systems, filling, and cleaning technology for the brewing industry. Project-engineered and customised systems tailored to individual requirements are also part of the manufacturer’s range of services.

Due to the increasing number of kegs from the Chinese market, European brewers face the challenge of carrying out beer filling in compliance with custody transfer requirements. While European kegs are standardised according to DIN or EN standards, this is not the case for Chinese keg models. To comply with legal metrology regulations when filling different types of kegs, filling machines in some countries of the European Union must be designed in accordance with the European Measuring Instruments Directive 2014/32/EU (MID) MI-005.

For the supply of a legally compliant filling machine to an end customer in southern Germany, the company was looking for an industrial partner experienced in custody transfer measuring systems for filling plants. The challenge lay in the fact that each individual keg in the filling line can vary in size and be equipped with a different connection system. This requires a highly flexible measuring system and straightforward adjustment of the measurement setup for each batch. Due to the complexity of the task, another manufacturer of process instrumentation had already declined this project request.

After a thorough analysis of the customer and legal metrology requirements, KROHNE took over the project management of the custody transfer (CT) measuring system. This included comprehensive technical consultancy as well as the supply of the metrologically relevant components. The measurement solution essentially consists of the OPTIFLUX 6300 electromagnetic flowmeter, a flow computer, and a printer.

The OPTIFLUX 6300 is a flowmeter designed for hygienic applications in the food and beverage industry. It was installed in the DN25 pipeline of the filling system via aseptic weld end fittings. The electromagnetic flowmeter (EMF) is equipped with a second, secure pulse output for custody transfer applications. This phase-shifted pulse output is offset by 90° relative to the original pulse and serves as a redundant control and safety parameter for the CT-compliant flow computer when processing measurement signals. The flow computer only counts the throughput when both pulse signals are received. In this setup, the double pulse signal corresponds to a defined volume of beer.

The flow computer was programmed to allow flexible adjustment to varying keg sizes and filling connections via analogue signal inputs. Batch changes can thus be conveniently controlled from the control room. In addition to a batch function, the flow computer also features a cleaning mode. For documentation purposes, it is connected to a printer approved for MI-005 custody transfer applications.

For the installation of the complete measuring system, the entire filling machine was tested and conformity-assessed in accordance with the Measuring Instruments Directive 2014/32/EU under Module B + F as a “measuring system for continuous and dynamic measurement of liquids other than water.” The conformity assessment under Module F, as well as the final metrological inspection, was carried out by a notified body at the site of the end customer.

The MI-005-compliant measuring solution enabled the customer to deliver a legally pre-approved keg filling plant efficiently. KROHNE managed the entire project for the measuring system and provided consulting services related to the EU type-examination certificate under Module B. This included the selection and qualification of individual components. KROHNE supplied the flowmeter OPTIFLUX 6300, the flow computer provided by a partner company, and a printer as a complete package solution.

Thanks to KROHNE’s custody transfer expertise, the application was designed to meet the customer’s requirements, while also effectively integrating the flow computer manufacturer. In this way, the challenges associated with varying keg sizes and connection types could be resolved in close collaboration with the customer. The preselection function programmed into the flow computer has been legally approved and provides the customer with extensive flexibility when using kegs from non-EU countries.

KROHNE has decades of experience in applications involving legally regulated measurements and billing of a wide range of media, from drinking water to liquids other than water (e.g., beer, oil, or liquefied gases), as well as industrial gases and heat quantities. The manufacturer and supplier of process instrumentation also has a specialised service team that provides comprehensive support for custody transfer filling, loading, and transport. This includes consulting on conformity assessment under Module F as well as final adjustments of the measuring system.