Fibre-optic measuring device

摘要

A fibre-optic measuring device for measuring the refractive index of liquids has a first optical fibre sensor, which can be dipped with its front, light-reflecting end into the liquid to be investigated, and into which the light of a light source can be coupled via a first input optical fibre and from which the light reflected at the front end of the first optical fibre sensor can be coupled out via a first output optical fibre to a first light detector. In order to be able to determine the refractive index independently of the turbidity of the liquid, a second optical fibre sensor, which can likewise be dipped into the liquid, is assigned to the first optical fibre sensor. The light-reflecting end of the second optical fibre sensor is differently shaped with respect to the light-reflecting end of the first optical fibre sensor, so that different sensitivities of the two optical fibre sensors are produced for the measurement of the refractive index and the measurement of turbidity. The light intensities reflected from the optical fibre sensors are evaluated in a microprocessor for the purpose of determining the refractive index and the turbidity. <IMAGE>