Patent ID: 7619723
Filing Date: 2009-11-17
Classification: G01N

Abstract:
1. A refractometer comprising a light source, an optical window to be positioned in a process liquid, means for directing a beam of rays from the light source to an interface (RP) between the process liquid and the optical window and leading back part of the beam of rays refracted from the interface to the inside of the optical window, and means for observing an image formed in the above manner, whereby the beam of rays from the light source is directed to the interface (RP) between the process liquid and the optical window from the side of the process liquid and in the direction of the interface and whereby the refractometer also comprises a ring element surrounding the optical window and made of an optical material, wherein the beam of rays from the light source is led to the ring element made of an optical material, the ring element being arranged to lead the beam of rays to the interface (RP) between the process liquid and the optical window.