ABB now has official proof of the high accuracy of its flowmeters following a recent visit by the United Kingdom Accreditation Service (UKAS). A surveillance visit by UKAS of ABB’s flow calibration facilities at its Stonehouse factory in Gloucestershire has resulted in ABB being certified as the only company in the UK with a calibration rig accurate to within an expanded uncertainty of ±0.027%.
ABB uses a process known as ‘wet calibration’ to test flowmeters under good flow conditions on its flow rigs. The resulting digital data is then used to show that the flowmeter has been calibrated for accurate measurement within the limits of its specification.
ABB’s Stonehouse calibration rigs are used to test flowmeters between 40mm and 2.4 metres in diameter. The rigs are used to obtain the accuracy of each flowmeter by comparing its measurement performance against a known value provided by a reference device such as a weigh tank, volume tank or meter prover. Any deviations from this value are then used to calculate the fundamental accuracy error value for the flowmeter.
ABB operates two flow rigs at its Stonehouse site, supplied by a one million litre underground tank. The rigs can be used to test virtually every type of flowmeter at flow rates from one millilitre to 2,700 litres per second.
The United Kingdom Accreditation Service is the sole national accreditation body recognised by government to assess, against internationally agreed standards, organisations that provide certification, testing, inspection and calibration services. Although ABB has had UKAS accreditation since 1982, this is the first time that it has been able to claim such a high accuracy for its calibration facilities.
"ABB spends considerable time and money constantly improving the accuracy of its flow equipment in order to keep up with customer demands," says Steve Dickson, Deputy Head of the Flow Calibration Laboratory. "Even though our flow calibration rig sets a global standard for accuracy, we will continue to strive for even better performance."