Ardagh Glass required a system to provide accurate and reliable content measurement on  five 15m-high glass cullet storage bins at its Doncaster site - typically a difficult level measurement application as the crushed glass (cullet) has a changing dielectric constant. Previously, engineers manually dipped each tank and reported on the storage levels but this presented accuracy issues and was time-consuming. Ardagh Glass required a level measurement system that would improve accuracy, facilitate remote monitoring and increase plant yield where possible through improved process control.

As a full-range solution provider, Endress+Hauser was contacted to devise a complete level monitoring system. With respect to the level measurement, Endress+Hauser suggested installing a Micropilot M FMR250 radar level gauge on each cullet bin as these non-contact radar devices offer continuous high accuracy monitoring. Moreover, the FMR250 is unaffected by the changing dielectric constant, filling noise, temperature layers and dust that could occur.

In terms of device monitoring, a potential pitfall was that Ardagh Glass's nearest Ethernet connection was located in a separate area of the building, making transmission and receipt of the signal difficult. Endress+Hauser solved this problem using Fieldgate remote monitoring gateways which allow data to be transferred directly to engineers' computers via a wireless link. This telemetry system, which includes data encryption, is capable of multiplexing 12 HART signals from the radar transmitters and is linked to the local area network for easy viewing. Fieldgate Viewer software was used to collect the measurements at 15-minute intervals, storing and displaying the values using a standard internet browser.

With Endress+Hauser's level measurement and monitoring system, future improvements have also been provided for - inventory control and even vendor-managed inventory can be achieved by automatic linkage to the cullet suppliers to indicate when reserves are low. This level of interoperability helps to realise increased plant yield, reduced downtime and improved accuracy.

After successful trials, a further three radar devices were installed with plans in the future to install a Micropilot M radar on every cullet storage bin. Nigel Hepworth, Batch Plant Team Leader, commented: "The Micropilot radar gauges and telemetry system have proved a great success - they're an investment into the plant's future and have eliminated the need for time-consuming manual dipping. Storage bin levels can be continuously monitored in both the control room and remote workstations, making stock re-ordering simple and efficient.