US4377446A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Carbon dioxide measurement
Assignee: BTG International Ltd
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Filing: 1982-04-15
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Granted: 1983-03-22
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Expires: 2002-04-15
Abstract
Abstract Carbon dioxide in the presence of oxygen is sensed by passage of the gas mixture through a layer of polymeric material and through a first, porous, working electrode in contact with a layer of aqueous electrolyte any oxygen being reduced at the electrode; any CO 2 gas passes through the aqueous electrolyte and through a CO 2 -permeable layer of polymeric material to a layer of non-aqueous solvent in contact with a second working electrode at which any CO 2 gas is reduced, causing a current to flow.
Inventors
- 👤 Wyndham J. Albery
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 13:34
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/26; G01N27/403; G01N27/404; G01N27/4045; G01N33/00; G01N33/0004; G01N33/0009; G01N33/0027; G01N33/0036; G01N33/004
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
157 words
Apparatus for sensing the presence of carbon dioxide in a fluid which may contain oxygen comprises in series array: a first layer of high polymeric material which is permeable to carbon dioxide and oxygen, and which has in contact with one surface a porous layer of metal which constitutes a first working electrode; in contact with said first working electrode a layer of an aqueous electrolyte; a second layer of high polymeric material which is permeable to carbon dioxide; in contact with said second layer a layer of a non-aqueous solvent; a second working electrode in contact with the non-aqueous solvent; and circuit means arranged to hold the first working electrode at a potential such that oxygen but not carbon dioxide is reduced in the aqueous electrolyte, to hold the second working electrode at a potential such that carbon dioxide is reduced in the non-aqueous solvent, and to sense any current flowing through the second working electrode.
Claim 2
Dependent Claim
157 words
Apparatus for sensing the presence of carbon dioxide in a fluid which may contain oxygen comprises in series array: a first layer of high polymeric material which is permeable to carbon dioxide and oxygen, and which has in contact with one surface a porous layer of metal which constitutes a first working electrode; in contact with said first working electrode a layer of an aqueous electrolyte; a second layer of high polymeric material which is permeable to carbon dioxide; in contact with said second layer a layer of a non-aqueous solvent; a second working electrode in contact with the non-aqueous solvent; and circuit means arranged to hold the first working electrode at a potential such that oxygen but not carbon dioxide is reduced in the aqueous electrolyte, to hold the second working electrode at a potential such that carbon dioxide is reduced in the non-aqueous solvent, and to sense any current flowing through the second working electrode.
Claim 3
Dependent Claim
20 words
Apparatus according to claim 1 in which the first working electrode is a metallised membrane of a high polymeric material.
Claim 4
Dependent Claim
12 words
Apparatus according to claim 1 in which the non-aqueous solvent is dimethylsulphoxide.
Claim 5
Dependent Claim
109 words
Apparatus according to claim 1 further comprising a first reference electrode in contact with the aqueous electrolyte; means for maintaining the potential of the first working electrode constant with respect to the first reference electrode; a first counter electrode in contact with the aqueous electrolyte; a second reference electrode in contact with the non-aqueous electrolyte; means for maintaining the potential of the second working electrode constant with respect to the second reference electrode; and a second counter electrode in contact with the non-aqueous electrolyte; currents corresponding to the reduction of any oxygen and any carbon dioxide present in the fluid flowing respectively through the first and second counter electrodes.
Claim 6
Dependent Claim
39 words
Apparatus according to claim 1 in which the first working electrode is of larger area than the second working electrode, and there is further provided a restriction to restrict access of the fluid to the first high polymeric layer.
Claim 7
Independent Claim
176 words
A method of sensing the presence of carbon dioxide in a fluid which may contain oxygen comprises: exposing to the fluid a first layer of high polymeric material which is permeable to carbon dioxide and oxygen, and which has in contact with one surface a porous layer of metal which constitutes a first working electrode, the first working electrode being in contact with a layer of an aqueous electrolyte remote from the fluid; holding the first working electrode at a potential such that oxygen but not carbon dioxide is reduced in the aqueous electrolyte; exposing to the aqueous electrolyte a second layer of a high polymeric material which is permeable to carbon dioxide, the second layer of high polymeric material being in contact with a layer of a non-aqueous solvent remote from the aqueous solvent, and there being a second working electrode in contact with the non-aqueous solvent; holding the second working electrode at a potential such that carbon dioxide is reduced in the non-aqueous solvent; and sensing any current flowing through the second working electrode.
Claim 8
Independent Claim
176 words
A method of sensing the presence of carbon dioxide in a fluid which may contain oxygen comprises: exposing to the fluid a first layer of high polymeric material which is permeable to carbon dioxide and oxygen, and which has in contact with one surface a porous layer of metal which constitutes a first working electrode, the first working electrode being in contact with a layer of an aqueous electrolyte remote from the fluid; holding the first working electrode at a potential such that oxygen but not carbon dioxide is reduced in the aqueous electrolyte; exposing to the aqueous electrolyte a second layer of a high polymeric material which is permeable to carbon dioxide, the second layer of high polymeric material being in contact with a layer of a non-aqueous solvent remote from the aqueous solvent, and there being a second working electrode in contact with the non-aqueous solvent; holding the second working electrode at a potential such that carbon dioxide is reduced in the non-aqueous solvent; and sensing any current flowing through the second working electrode.
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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) | 1986-03-21 | 1986-09-20 | 1987-03-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-03-21 | 1990-09-20 | 1991-03-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-03-21 | 1994-09-20 | 1995-03-22 | $7700.00 | Window Closed / Lapsed |