Patent ID: 8040499

Claim:
A transmitted light refractometer, comprising: a light source on a radiation side of an immersible portion of said transmitted light refractometer which is immersible in a process liquid; an illumination optics unit configured for parallelizing light emitted from said light source; a reversing optics unit which is oriented relative to said illumination optics unit such that the reversing optics unit deflects the parallel beam into a general direction back to said radiation side of said immersible portion along a reversed light path; a window being disposed in said immersible portion, a surface of said window being in contact with the process liquid when said immersible portion is immersed, said surface being aligned with a first plane oriented generally perpendicular to said reversed light path; a measurement prism being disposed in said immersible portion including a light entry surface in contact with the process liquid which is aligned with a second plane oriented at an oblique angle with respect to said reversed light path so as to refract said light traveling along said reversed light path such that said light is redirected along a refracted light path, said measurement prism further including a light exiting surface through which said light traveling along said refracted light path exits said measurement prism and passes back to the radiation side; and a focusing optics unit configured to focus the light which exits said measurement prism onto a detector plane, the focusing optics unit and the detector plane being arranged on the radiation side, so that only one access to the process medium is required.