In situ Calibration of Flow Meters

Up to now flow meters have to be demounted from their pipe structure for the calibration. This process of demounting measurement instruments implies an interruption on the supply and high costs. Therefore, after an initial manufacturer’s calibration, large heat and water flow meters are used during decades without any interruption.  Measuring errors are generated due to the difference between operational and calibration conditions on the test facility, for instance temperature, inflow and flow rate. The measurement errors can produce significant economic consequences (incorrect billing) leading to a deterioration of customer relations.

ILA R&D GmbH has developed in collaboration with OPTOLUTION and the German National Metrology Institute (PTB-Berlin)  a new and inovative laser optical calibration technique. This technique permits on-site calibration of flow meters without having to interrupt operations or demounting the measurement instrument. For this purpose, the velocity profile in the pipe is acquired with the help of a LDV system, then the corresponding volume flow rate is calculated. The calibration of the installed flow meter is performed by comparison with the laser optical transfer standard. For this method, the German National Metrology Institute (PTB) has certified a measurement error of +/-0,6% (under reference conditions).

The measurements with the ILA equipment are executed in cooperation with our partner OPTOLUTION, who is certified as a calibration laboratory according to DIN EN ISO/IEC 17025.

Fig. 1: Hot Tapping in cooperation with Vattenfall
Fig. 2: LDV In situ Calibration of a Flow Meter