Multi-level fiber-optic liquid-level sensing system
US4979797A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 6, 1989 |
| Grant date | Dec 25, 1990 |
| Priority date | — |
| Expiry date | Oct 6, 2009 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S250/903
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Plural sensor prisms and associated opticalfiber circuits are arrayed as a single vertical stem by which the individual prisms serve for response to each of a plurality of different liquid levels. Each prism is formed of light-transmitting plastic material which can be injection-molded to precision dimensions. The body configuration is such as to adapt to arrayed interconnection with tubular members, also of plastic, and bonded at telescoping fit of each prism to the tubular member or members to which it is connected. The prism configuration relied upon for sensed response to the presence of immersing liquid (as compared to air) is a solid region having an exterior profile which includes a downwardly convergent conical surface portion at least at spaced locales which are at equal but opposite offset from the cylindrical body axis, wherein the geometric apex angle of downward convergence is 90 degrees. As long as a given prism is exposed to air, a large amount of light is transmitted (by reflection within the prism) from a transmission optical fiber to a receiving optical fiber. But when immersed in a liquid, a portion of the light from the transmitting fiber is refracted into the l…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.