Carbon dioxide sensing system
Abstract
Abstract Low cost system for sensing carbon dioxide content of ambient air. It comprises a thin layer of a chemical reversibly absorbent for carbon dioxide, the pH of which changes in relation with the amount of absorbed carbon dioxide at any time; an indicator present in said film which changes color in accordance with the pH, and a photoelectric system to produce an electric signal proportionate to said color change. In this system substantial independence of humidity is gained by the use as principal solvent in the said thin layer of an ionizing solvent having a vapor pressure in the range of 0-10 mm at temperatures up to 150*F, and compatible with the other components of the system.
Inventors
- 👤 K Guenther
Bibliographic Details
Claims Analysis
Total Claims: 2References Cited (Backward Citations)
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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) | 1976-08-27 | 1977-02-26 | 1977-08-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-08-27 | 1981-02-26 | 1981-08-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-08-27 | 1985-02-26 | 1985-08-28 | $7700.00 | Window Closed / Lapsed |