US4701052A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Dew point hygrometer
Assignee: Individual
•
Filing: 1985-05-24
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Granted: 1987-10-20
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Expires: 2005-05-24
Abstract
Abstract A hygrometer utilizing condensation at the dew point to determine the water content of a gas. The presence of the condensate is determined using linear polarized light to distinguish the condensate from the metal surface on which it forms. A temperature gradient is established across the surface so that condensate forms on only part of the surface. The portion of the surface covered gives an indication of the temperature of the dew point.
Inventors
- 👤 Oscar W. Schoen, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 15:46
CPC Classifications
G; G01; G01N; G01N25/00; G01N25/56; G01N25/66; G01N25/68
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
93 words
A dew point hygrometer, comprising: a specular metal surface; a heat sink for cooling said metal surface; a polarized light source for providing linearly polarized light incident on said metal surface; an analyzer for receiving light reflected from said metal surface and transmitting only light with certain predetermined polarization; a light detector for producing an output when light is transmitted through said analyzer; wherein condensation forming on said cooled metal surface causes said reflected light to change polarization and be blocked by said analyzer, thus causing said light detector to produce no output.
Claim 2
Dependent Claim
93 words
A dew point hygrometer, comprising: a specular metal surface; a heat sink for cooling said metal surface; a polarized light source for providing linearly polarized light incident on said metal surface; an analyzer for receiving light reflected from said metal surface and transmitting only light with certain predetermined polarization; a light detector for producing an output when light is transmitted through said analyzer; wherein condensation forming on said cooled metal surface causes said reflected light to change polarization and be blocked by said analyzer, thus causing said light detector to produce no output.
Claim 3
Dependent Claim
12 words
The hygrometer according to claim 1 wherein said analyzer is a polarizer.
Claim 4
Dependent Claim
14 words
The dew point hygrometer according to claim 1, wherein said metal surface is planar.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-10-19 | 1991-04-20 | 1991-10-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-10-19 | 1995-04-20 | 1995-10-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-10-19 | 1999-04-20 | 1999-10-20 | $7700.00 | Window Closed / Lapsed |