In maintaining the standard of its leading range of measuring instruments, Endress+Hauser South Africa has access to the largest and most advanced flowmeter calibration centre in the world. The facility is located at the Endress+Hauser Flowtec production plant in Cernay, France.
Although there are local flow rigs, they are not able to calibrate the larger diameters of flowmeters. Each and every Endress+ Hauser flowmeter is calibrated at this rig and recalibration for ISO 9001 requirements can also be done at relatively low costs.
Boasting calibration technology in flow measurement as one of its core competencies, the installation in Cernay is accredited as a calibration laboratory in accordance with EN45001 standards. Within the framework of the European EAL (European Organisation for the Accreditation of Laboratories), calibrations traceable to the national standard are therefore possible. Such calibrations are fully recognised in all EAL member countries as well as many others.
While the Flowtec facility relies on the latest technological trends and developments in producing flowmeters, continually increasing accuracy requirements have necessitated that test equipment be developed to the same degree. The calibration centre in Cernay facilitates this, allowing for a spectrum for calibration that ranges from a few droplets up to six million litres per hour for flowmeters with nominal diameters from 2-2000 mm (DN 2 to DN 2000).
The three independent water reservoirs needed for calibration have a total capacity of 1,35 million litres. Water from these tanks is pumped to the top of a seven-storey water tower with an overflow at a height of 23,9 m, by seven separately controlled 850 kVA pumps. From there the water flows downwards, free of pulsation, via several pipes with diameters from 80 to 1000 mm as required, to a total of seven test rigs. Depending on the diameter of the flowmeter under test and the measuring range to be calibrated, special control valves adjust the flow to the desired setpoint within seconds.
Endress+Hauser Flowtec uses two distinctly different calibration methods. The measuring uncertainty of the device under test can be determined either volumetrically, by comparison to three calibrated precision Endress+Hauser flowmeters in series, or gravimetrically (drop-test) using a flow diverter valve. This valve leads the water flow into one of three weigh tanks, with capacities of 400, 500 and 50 000 kg. The precision scales have such a high resolution that, for example, the contents of the 50 000 kg vessel can be weighted within 50 g. These values are then compared with those from the device under test, which is calibrated accordingly.
The entire calibration arrangement is controlled and monitored by several networked computers. Many of the measurement and control variables, such as temperature, pressure, level or flow, are digitally transmitted, monitored and evaluated via Profibus DP and using Endress+Hauser instruments.
During the planning of the calibration centre, emphasis was placed on operational reliability. As a result, many of the components, including the actual measurement and calibration facilities, were designed with redundancy in order to ensure normal production operation even during maintenance or the breakdown of parts of the system. All components coming into contact with the softened, bacteria-free water are made from stainless steel.
Endress+Hauser is confident that, with this calibration centre, it has set a milestone for even higher product quality.
| Tel: | +27 11 262 8000 |
| Email: | [email protected] |
| www: | www.endress.com |
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