Emitter-Doppler-anemometer for determining particle-like scattering objects in stream, has control unit performing controllable position change of overlapping region in stream and measuring volume in stream

摘要

The anemometer (10) has a data detection system (19) for processing a scattering light (17) to a burst signal with an evaluation unit (20) to determine speed of scattering objects (11) that is provided in a stream (12). A trigger unit (29) transmits the burst signal, and a comparison unit (23) compares interference contrast of the signal with a preset contrast threshold. A control unit (26) stands in connection with the evaluation unit and performs controllable position change of an overlapping region (7) and a measuring volume (70) in the stream that is illuminated by an emitter (1) i.e. LED. An independent claim is also included for a method for determining local speed in a stream.