LIQUID REFRACTOMETER AND LIQUID CONCENTRATION METER USING SAME

PURPOSE:To measure a refractive index on an off-line basis at all times by putting an image fiber which photodetects and guides measurement light to a detection part in a sensor probe. CONSTITUTION:The sensor probe 9 contains a light guide 2 which guides the measurement light, a sensor part 6 which refracts the measurement light guided by the light guide 2 and detects the refractive index of the sample liquid, and the image fiber 8 which photodetects and guides the measurement light projected from the sensor part 6. Then the sensor probe 9 is dipped directly in the sample liquid first. Then the measurement light which is guided 8 is detected by a detection part 7 as a light signal, which is converted into an electrode signal by various photodetecting elements. The data which is converted into the electric signal is processed 16 by using a relational expression to find the refractive index of the sample liquid. Thus, only the sensor probe 9 is dipped directly in the sample liquid without sampling the sample liquid, so the refractive index of the liquid is measured on an on-line basis at all times.