LDV measurements were performed on a suction pipe to acquire the volume flow of a street sweeper during the operating conditions. These measurements were conducted to produce more reliable and accurate results of the volume flow in comparison with the existing conventional measuring techniques, such as a hotwire anemometer or a vane anemometer, which tend to produce noisy results.
In order to produce optimized flow conditions at the test-section a flow calming pipe section was installed and equipped with a special glass-pipe at the cross-section for the LDV measurement. After that the LDV measurements were conducted by measuring the local velocities of the whole cross-section. By numerical integration of the measured velocities the average volume flow was calculated with a high precision. With the knowledge of the measuring-uncertainty it was finally possible to accomplish the chain of traceability of the tested conventional flow-measuring devices to the national standards of metrology.