Patent ID: 8218133

Claim:
A refractive index tool to discriminate between a plurality of fluids, the refractive index tool comprising: a wave source configured to generate a wave; a transparent rod configured to receive the wave from the wave source; and a wave detector configured to receive the wave from the transparent rod, wherein the transparent rod is a curved transparent rod, wherein the wave source and the wave detector are provided at a first end of the transparent rod so that the wave emitted by the wave source travels through the transparent rod and experiences total internal refraction prior to arriving at the wave detector, and wherein the refractive index tool is configured to measure an intensity of the wave received by the wave detector, the intensity of the wave being related to a refractive index of the transparent rod and a refractive index of a fluid in which the transparent rod is immersed, the refractive index of the transparent rod being higher than the refractive index of the fluid in which the transparent rod is immersed.