Method of Measuring Liquid Level with a Thermal Interface Detection
Abstract
A method of measuring the position of a liquid surface within a vessel is described. An optical fiber is provided which has first and second ends and has an energy-absorbing element of a predetermined length disposed upon a portion of the cladding thereof such that there is a thermal interface between the energy-absorbing element and the cladding. The optical fiber is then positioned in the vessel so that the energy-absorbing element disposed thereon extends a known distance into the vessel along a Known depth gradient of the vessel and so that the energy-absorbing element will intersect the liquid surface over the anticipated range of positions thereof. Single-frequency, coherent light is then transmitted through the core of the optical fiber by launching it into the first end of the optical fiber. A pulse of energy is applied across the entire length of the energy-absorbing element to heat it, and then the transmitted light is received from the second end of the optical fiber. The change in phase of the transmitted light resulting from applying the pulse of energy is then measured, and the position of the liquid surface is then determined in accordance with the change in phase.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 22, 1994
- Accession Number
- ADD019820
Entities
People
- Llyod C. Bobb
Organizations
- United States Department of the Navy