The light source sends light to the interface between a prism and the process solution, where the rays meet the surface at different angles. Depending on the angle, some rays undergo a total internal reflection. The rest of the light is refracted into the process solution.
This angle is a function of the refractive index and therefore the concentration of the solution. A CCD-camera detects the optical image. The image is transformed point-by-point into a digital signal. Digital signal processing is used to locate the exact shadow line position and to determine the refractive index nD.
A built-in temperature sensor measures the temperature T on the interface of the process liquid. The sensor converts the refractive index nD and temperature T into Brix units.
The diagnostics program ensures that the measurement is reliable.
Thus, an optical image with a dark sector and a light sector is created. The angle corresponding to the shadow line is called the critical angle of total internal reflection.
The light source emits light at the interface, between a prism and the process solution, where the rays meet the surface at different angles.Depending on the angle, some rays undergo a total internal reflection. The rest of the light is refracted into the process solution. Thus an optical image with a dark sector and a light sector is created. The angle corresponding to the shadow line is called the critical angle of total internal reflection. This angle is a function of the refractive index and therefore the concentration of the solution. A CCD-camera detects the optical image. The image is transformed point-by-point into a digital signal. Digital signal processing is used to locate the exact shadow line position and to determine the refactive index nD.
