Material e.g. fluid, concentration measuring device e.g. immersion sensor, has adjusting device to adjust distance between deflecting unit and transmitter and/or receiver such that unit forms space with housing in one position of unit

摘要

The device has a transmitter (4) and a receiver (5), which are arranged in a housing (7) for optical radiation. A deflecting unit (9) deflects the radiation from the transmitter to the receiver. An adjusting device (10) adjusts the distance between the unit (9) and the transmitter and/or receiver such that the deflecting unit forms a closed hollow space with the housing in one position of the deflecting unit. An annular gap is found between the deflecting unit and housing in another position of the deflecting unit, and enables the inflow of the material between the deflecting unit and housing.