Chilled mirror hygrometer with performance monitoring
US4629333A · kind A · utility
15Cited by
2References
6Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Oct 19, 1984 |
| Grant date | Dec 16, 1986 |
| Priority date | — |
| Expiry date | Oct 19, 2004 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N25/68
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A radiation source directs light at a mirror which reflects to a first photosensor. As a dew point is reached, scattered light is reflected to a second photosensor to indicate dew point. Rather than periodically interrupting operation to test reflectivity of the mirror or to perform a heating cycle, operation is monitored continuously. The common mode output of both the first and second photosensors is monitored. When below a threshold level, the output indicates the need for cleaning the mirror. It may also be used in a closed loop to increase light source intensity as mirror reflectivity decreases.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.