Method and apparatus for detecting hydrocarbon fuels in a vapor state with an absorber-expander member
US5378889A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 23, 1993 |
| Grant date | Jan 3, 1995 |
| Priority date | — |
| Expiry date | Sep 23, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2021/7783
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method and apparatus for detecting the presence of hydrocarbon analyte in at least one of a liquid and vapor state. The apparatus (21) includes an optical fiber (22), an absorber-expander (31) mechanically coupled (32) to the optical fiber (22) to produce a change in transmission of light along the fiber (22) upon absorption of the hydrocarbon (33). The absorber-expander (31) is selected to absorb hydrocarbons, but not water, and to be capable of multiple reversible expansion and contraction cycles without significant structural degradation. Methyl terminated, silica and iron oxide filled, dimethyl polysiloxane provides a material which will experience substantial swelling in the presence of a hydrocarbon and yet is substantially reversible on desorption of the hydrocarbon from the absorber-expander (31). The method includes positioning an optical fiber (22) having such an absorber-expander (31) for absorption of hydrocarbons and detecting the decrease in light transmission produced by expansion of the absorber-expander (31), for example, by one of microbending and axial misalignment. The location of the absorber-expander (31) along strand (22) can be determined by optical time d…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.