Time is money, therefore a continuous process is the ideal in industry. Some interruptions in operations, however, are unavoidable – as a result of the calibration of the measuring systems used, for example. The respective instruments are taken out, sent off, and are returned after some days to be reinstalled. The result is significant process downtime, added to the risk that the highly-sensitive measuring instruments could be damaged in transit. The obvious disadvantages of such external testing can be minimised, however, through a mobile calibration service.
In WIKA’s experience, having offered such an on-site service for pressure and temperature measuring instruments since the middle of the 1990s, the entire control process can be sped-up by as much as a factor of five. This means that while a process can stand idle for five days due to a calibration, with direct inspection at the customer’s site, it can be up and running after one day.
The demand is increasing
The word is out in the industry. The demand has risen steadily over the last few years. WIKA’s certified calibration vans are in constant use. Each year they drive to around 250 companies across a range of different industries – one fifth of those more than once. Since 2008, for example, every quarter a WIKA laboratory has rolled up at the Airbus factory in Hamburg. At this aircraft manufacturer, over 12 months, several hundred measuring instruments must be calibrated, from simple pressure gauges through transmitters and up to highest-precision reference instruments.
The more test items, the more effective using the calibration van becomes. Nevertheless, despite the high fixed cost, the service can even be worth it for as few as 10 instruments. The local requirements are not complicated, whether for Airbus or a medium-sized equipment manufacturer. The vehicle only needs a parking place and a power connection.
The first step is the climate control of the vehicle. In accordance with DKD guidelines, a stable set temperature of between 18 and 28°C must be maintained. The subsequent test of the pressure and temperature measuring instruments is made successively to avoid unnecessary loss of time. For safety reasons, customers remove and re-install the instruments themselves. If required, the WIKA tester can also calibrate the instruments in-situ in the plant. This, for example, is the case with Airbus, where in addition to the measuring instruments, the complete evaluation unit, including the measuring station, must be checked.
The vans are fully self-contained
The basic configuration of the calibration van covers most test requirements. On-board oxygen bottles and a compressor deliver pneumatic and hydraulic pressure to enable the control of the accuracy of pressure readings from -1 to 1600 bar. Each vehicle has 10 fixed and mobile reference instruments for pressure and temperature, with an accuracy of 0,01%. Additional equipment can be brought from the WIKA laboratory if, as with Airbus, there are a wider range of requirements during a visit.
The calibration van is a rolling all-inclusive package. In addition to the measuring instruments, it also has a work bench and standard spare parts for minor repairs. All information on the test procedure is entered into a PC, and the results printed out immediately.
As the example of Airbus demonstrates, it is not only the demands on the technical equipment in our calibration vans which are high. Its crew – one man per vehicle – must have experience across a broad product range. After all, they do not only calibrate instruments from their own company.
WIKA Namibia already has a calibration vehicle in service, and in South Africa, WIKA’s Cape Town branch has just taken delivery of its own mobile calibration vehicle.
| Tel: | +27 11 621 0000 |
| Email: | [email protected] |
| www: | www.wika.co.za |
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