Physikalisch-Technische Bundesanstalt

The Working Group "Liquid Test Facilities" handles all tasks related with the operation and further development of the liquid test facilities of the Department. These tasks are:

-        the Hydrodynamic Test Field (HTF)

-        the experimentation and water meter test rig

-        the test rig for petroleum and

-        the pipette testing facility

The Hydrodynamic Test Field

The Hydrodynamic Test Field is the national standard of the volume and flow-rate measurements of liquids. It realises all four relevant measurands: mass, volume, mass flowrate and volume flowrate of a flowing liquid. It is operated with the fluid "water" in a flowrate range from 0.3 m3/h to 2100 m3/h and with an expanded relative measurement uncertainty of 0.02 %. The units are realised gravimetrically with the aid of three weighing systems, based on a 30-ton balance, a 3-ton balance and a 300 kg balance which are used as a function of the respective flowrate.

Characteristics and calibration capabilities of the Hydrodynamic Test Field:

Test rig for petroleum

Scientific work for the development of transfer standards which are independent of the fluid used requires experimental investigations and verifications with liquids other than water. For this purpose, in particular the test rig for petroleum is used. Both the principle of measurement as well as the test fluid differ from those of the HTF. This test rig works volumetrically. As basic reference standards, four geometrically measured standard tank with capacities of 5000 L, 1000 L, 200 L and 100 L are used. The filling stage of the tanks is measured with the aid of an automatic height measuring system based on magnetostriction.

The test fluid used is white spirit which has a dynamic viscosity of 0.8 mPa·s and a density of 770 kg/m3. The flowrate range which can be realised lies between 0.6 m³/h and 120 m³/h. The test rig can be operated in both, flying and standing start-stop regime. The flowrate can be generated via constant-head tanks and also by means of direct pump operation. The expanded measurement uncertainty, which has been confirmed by international comparison measurements, amounts to 0.05 %.

Standard tanks of the petroleum test rig with capacities of 5000 litres, 1000 litres, 200 litres and 100 litres.

Experimentation and water meter test rig

The experimentation and water meter test rig is operated in the flowrate range from 10 L/h to 20 m3/h and thus covers the small flowrates which are of interest in particular for the residential and domestic water meter range. Test medium is water with temperatures between 15 °C and 35 °C. The maximum test pressure in pump operation amounts to 6 bar, in the case of a mode of operation via constant-head tank to 3 bar. The test rig can be operated both in flying and in standing start-stop regime. The expanded measurement uncertainty amounts to 0.05 %.

Pipette testing facility

In addition to the test rigs which are operated with flowing fluids, the measurement of smaller static volumes is of importance. The verification of fuel dispensers or the volumetric measurement of tank lorries is performed solely by means of volume standards. Also within the scope of the international harmonisation of fluid measurements, comparison measurements are carried out by means of static volume standards (volume standards and pipettes).

The pipette testing facility of PTB is operated with distilled water and is designed for volumes between 1 litre and 100 litres. It has given proof of its excellent metrological parameters on the occasion of numerous international comparisons, most recently within the scope of the key comparison which was completed in 2006 where the stated expanded measurement uncertainty of 0.004 % could impressively be confirmed.