CLEANING SYSTEM FOR PROBE UNIT

The present invention relates to a self-cleaning probe for performing optical measurements in a gas or liquid flow. The probe comprises a measuring cell defining a passage for the gas or liquid to be measured to pass through, and includes minimum a first and second optical interface on opposite sides of the passage. The probe further comprises at least one optical light source emitting an optical signal and a detector for receiving an optical signal having propagated partly or fully through the gas or liquid flow from the first to the second interface. All optical interfaces are acoustically coupled to one acoustic transducer connected to a power source, adapted to produce vibrations in the frequency range of 5 kHz-1 MHz, the vibrations being substantially perpendicular to the plane of the interfaces and the acoustic energy exceeding the cavitation threshold in a liquid, so as to remove deposits on the optical interfaces.