Patent US4634856A successfully refreshed from Google Patents.
US4634856A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fiber optic moisture sensor with moisture-absorbing reflective target
Assignee: United States Department of Energy
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Filing: 1984-08-03
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Granted: 1987-01-06
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Expires: 2004-08-03
Abstract
Abstract A method and apparatus for sensing moisture changes by utilizing optical fiber technology. One embodiment uses a reflective target at the end of an optical fiber. The reflectance of the target varies with its moisture content and can be detected by a remote unit at the opposite end of the fiber. A second embodiment utilizes changes in light loss along the fiber length. This can be attributed to changes in reflectance of cladding material as a function of its moisture content. It can also be affected by holes or inserts interposed in the cladding material and/or fiber. Changing light levels can also be coupled from one fiber to another in an assembly of fibers as a function of varying moisture content in their overlapping lengths of cladding material.
Inventors
- 👤 Randy R. Kirkham
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 15:13
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/75; G01N21/77; G01N21/7703; G01N21/17; G01N21/41; G01N21/43; G01N21/431; G01N21/78; G01N21/81; G01N21/84; G01N21/85; G01N21/8507
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
89 words
A method for monitoring environmental moisture changes, comprising the following steps: locating a optical fiber assembly within the environmental area being monitored; transmitting light signals through the optical fiber assembly from a light source to and from a target whose reflectance is a function of the target's moisture content; measuring the returned light reflected by the target; and detecting changes in the light signals transmitted through the optical fiber assembly from the light source as an indication of the moisture conditions to which the optical fiber assembly is subjected.
Claim 2
Independent Claim
89 words
A method for monitoring environmental moisture changes, comprising the following steps: locating a optical fiber assembly within the environmental area being monitored; transmitting light signals through the optical fiber assembly from a light source to and from a target whose reflectance is a function of the target's moisture content; measuring the returned light reflected by the target; and detecting changes in the light signals transmitted through the optical fiber assembly from the light source as an indication of the moisture conditions to which the optical fiber assembly is subjected.
Claim 3
Independent Claim
80 words
An apparatus for monitoring environmental moisture, comprising: a optical fiber assembly located within the environmental area being monitored; a light source for directing light signals through the optical fiber assembly; a moisture-sensitive reflective target at an end of at least one optical fiber within the optical fiber assembly and exposed to said light source; and detection means for measuring changes in the reflectance of said target as an indication of the environmental moisture conditions to which the target is subjected.
Claim 4
Independent Claim
80 words
An apparatus for monitoring environmental moisture, comprising: a optical fiber assembly located within the environmental area being monitored; a light source for directing light signals through the optical fiber assembly; a moisture-sensitive reflective target at an end of at least one optical fiber within the optical fiber assembly and exposed to said light source; and detection means for measuring changes in the reflectance of said target as an indication of the environmental moisture conditions to which the target is subjected.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-01-05 | 1990-07-07 | 1991-01-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-01-05 | 1994-07-07 | 1995-01-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-01-05 | 1998-07-07 | 1999-01-06 | $7700.00 | Window Closed / Lapsed |