×

Fibre optic sensor for the continuous measurement liquids level and other parameters

  • US 4,942,306 A
  • Filed: 12/30/1988
  • Issued: 07/17/1990
  • Est. Priority Date: 12/30/1988
  • Status: Expired due to Fees
First Claim
Patent Images

1. An indicating device for showing the level of the interface between two fluids in a container, wherein one fluid has a higher index of refraction than the other, comprising at least two optical fibres, each having at least a portion thereof embedded in a transparent substrate material of similar refractive index to that of the fluid with a higher refractive index, one of said fibres being a source fibre optically connected to a light source, the other being doped with a fluorescent doping material and being a detector fibre optically connected to a detector, the fibres being arranged within the substance such that light emitted from said source fibre illuminates the interior of the substrate, which serves as a larger waveguide, and (a) is coupled into said detector fibre when total internal reflection occurs at the substrate/fluid interface, which is the case when air or a fluid of relatively low refractive index is present, or (b) is not coupled into said detector fibre when refraction occurs at the substrate/fluid interface, which is the case when the fluid of higher refractive index, namely the fluid whose level is to be measured, is present.

View all claims
  • 11 Assignments
Timeline View
Assignment View
    ×
    ×