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US4755473A
Expired / Lapsed
US
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Method of detecting carbon dioxide gas
Assignee: Sekisui Kaseihin Kogyo KK
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Filing: 1986-05-16
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Granted: 1988-07-05
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Expires: 2006-05-16
Abstract
Abstract The presence of carbon dioxide contained in a gas can be detected through measurement of the change in the electrical resistance of a hydroxyapatite in contact with carbon dioxide gas. The sensitivity of the hydroxyapatite to carbon dioxide gas can be enhanced by the formation of a composite of the hydroxyapatite with an inorganic carbonate, e.g., sodium carbonate or calcium carbonate. The sensitivity to carbon dioxide gas can be further enhanced by the formation of a composite of the hydroxyapatite with an inorganic halide, e.g., calcium chloride.
Inventors
- 👤 Tadashi Nishino
- 👤 Masayuki Nagai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 14:02
CPC Classifications
G; G01; G01N; G01N33/00; G01N33/0004; G01N33/0009; G01N33/0027; G01N33/0036; G01N33/004; G01N27/00; G01N27/02; G01N27/04; G01N27/12; Y; Y10; Y10T; Y10T436/00; Y10T436/20; Y10T436/204998
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
77 words
A method for the detection of carbon dioxide gas comprising bringing carbon dioxide containing gas into contact with a detection element comprising a hydroxyapatite according to the formula (I): M.sub.10 (ZO.sub.4).sub.6 (OH).sub.2 (I) wherein M is an element selected from the group consisting of Ca, Ba, Sr, Pb and Cd, and Z is an element selected from the group consisting of P, As, and V; and measuring the change in the electrical resistance of said detection element.
Claim 2
Independent Claim
77 words
A method for the detection of carbon dioxide gas comprising bringing carbon dioxide containing gas into contact with a detection element comprising a hydroxyapatite according to the formula (I): M.sub.10 (ZO.sub.4).sub.6 (OH).sub.2 (I) wherein M is an element selected from the group consisting of Ca, Ba, Sr, Pb and Cd, and Z is an element selected from the group consisting of P, As, and V; and measuring the change in the electrical resistance of said detection element.
Claim 3
Dependent Claim
33 words
A method according to claim 1 further comprising drying said carbon dioxide containing gas by passing the gas through a means for dehumidification before bringing said gas into contact with said detection element.
Claim 4
Dependent Claim
24 words
A method according to claim 1 further comprising heating said carbon dioxide containing gas before bringing said gas into contact with said detection element.
Claim 5
Dependent Claim
12 words
A method according to claim 1 further comprising heating said detection element.
References Cited (Backward Citations)
JPS5626401A
Cited
US4419889A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-07-05 | 1992-01-04 | 1992-07-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-07-05 | 1996-01-04 | 1996-07-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-07-05 | 2000-01-04 | 2000-07-05 | $7700.00 | Window Closed / Lapsed |