Patent US4943364A successfully refreshed from Google Patents.
US4943364A
Expired / Lapsed
US
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Fiber optic CO2 sensor
Assignee: Becton Dickinson Critical Care Systems Pte Ltd
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Filing: 1986-06-23
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Granted: 1990-07-24
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Expires: 2006-06-23
Abstract
Abstract A fiber-optic probe for measuring the partial pressure of CO 2 in a medium includes a single optical fiber having a distal end; a mirror; a hydrolyzed dye/gel polymer, the dye being in contact with a bicarbonate solution; a solution permeable membrane covering the fiber distal end, hydrogel and mirror; and a gas-permeable membrane covering the solution permeable membrane.
Inventors
- 👤 Mark Koch
- 👤 Richard C. Murray, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 22:54
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/62; G01N21/63; G01N21/64; G01N21/6428; G01N21/643; G01N21/75; G01N21/77; G01N21/7703; G01N21/78; G01N21/80; G01N21/645; G01N2021/6484; G01N2021/7706; G01N2021/772; G01N2021/7769; G01N2021/7786
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
193 words
A fiber-optic probe for measuring the partial pressure of carbon dioxide in a medium, comprising: a gas-permeable membrane; a hydrolyzed hydrogel including a dye/bicarbonate/gel acrylic or ethylene oxide polymer within the gas/permeable membrane, the hydrogel having been prepared from a chemically and optically unstable dye/gel acrylic or ethylene oxide polymer which, prior to treatment, contains weakly bonded dye molecules and exhibits a substantial drift in measured pH with time accompanied by an increase in protonation constant, by a treatment comprising (1) contacting the unstable polymer with a dilute aqueous base solution for a period of time sufficient to remove weakly bonded dye molecules from the polymer (2) washing the base-treated polymer with water to remove substantially all the base, (3) contacting the washed polymer with a solvent having a high affinity for water to remove water from the polymer and give a polymer characterized by chemical and optical stability with respect to dye loss with time and a consistently repeatable protonation constant, and (4) conditioning the stable polymer by contacting it with a bicarbonate solution; means for providing light to the hydrolyzed hydrogel, and means for transmitting absorbable light from the hydrolyzed hydrogel.
Claim 2
Dependent Claim
193 words
A fiber-optic probe for measuring the partial pressure of carbon dioxide in a medium, comprising: a gas-permeable membrane; a hydrolyzed hydrogel including a dye/bicarbonate/gel acrylic or ethylene oxide polymer within the gas/permeable membrane, the hydrogel having been prepared from a chemically and optically unstable dye/gel acrylic or ethylene oxide polymer which, prior to treatment, contains weakly bonded dye molecules and exhibits a substantial drift in measured pH with time accompanied by an increase in protonation constant, by a treatment comprising (1) contacting the unstable polymer with a dilute aqueous base solution for a period of time sufficient to remove weakly bonded dye molecules from the polymer (2) washing the base-treated polymer with water to remove substantially all the base, (3) contacting the washed polymer with a solvent having a high affinity for water to remove water from the polymer and give a polymer characterized by chemical and optical stability with respect to dye loss with time and a consistently repeatable protonation constant, and (4) conditioning the stable polymer by contacting it with a bicarbonate solution; means for providing light to the hydrolyzed hydrogel, and means for transmitting absorbable light from the hydrolyzed hydrogel.
Claim 3
Dependent Claim
23 words
A fiber-optic probe as recited in claim 1 wherein the gel polymer is selected from the group consisting of polyacrylamides and polyethylene oxides.
Claim 4
Dependent Claim
15 words
A fiber-optic probe as recited in claim 2 wherein the gel polymer is a polyacrylamide.
Claim 5
Dependent Claim
27 words
A fiber-optic probe as recited in claim 1 wherein the dye is selected from the group consisting of phenol red, cresol red, neutral red and bromothymol blue.
Claim 6
Dependent Claim
15 words
A fiber-optic probe as recited in claim 4 wherein the gel polymer is a polyacrylamide.
Claim 7
Dependent Claim
22 words
A fiber-optic probe as recited in claim 1 further comprising a solution-permeable membrane interposed between the gas-permeable membrane and the hydrolyzed hydrogel.
Claim 8
Dependent Claim
32 words
A fiber-optic probe as recited in claim 6 wherein the solution-permeable membrane is a hollow fiber membrane selected from the group consisting of porous polyethylenes, porous polypropylenes, porous polytetrafluorethylene and dialysis tubing.
Claim 9
Dependent Claim
35 words
A fiber-optic probe as recited in claim 7 wherein the gas-permeable membrane is coated on the exterior of the hollow-fiber membrane and is selected from the group consisting of silicone rubbers, latex rubbers and polyurethanes.
Claim 10
Dependent Claim
69 words
A fiber-optic probe as recited in any one of claims 1-8, inclusive, wherein the means for providing light to the hydrolyzed hydrogel comprises an optical fiber having a distal end located within the gas-permeable membrane and the means for transmitting absorbable light from the hydrolyzed hydrogel comprises a mirror located within the gas-permeable membrane, the hydrogel being interposed between the distal end of the optical fiber and the mirror.
References Cited (Backward Citations)
US4194877A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-07-23 | 1994-01-22 | 1994-07-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-07-23 | 1998-01-22 | 1998-07-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-07-23 | 2002-01-22 | 2002-07-24 | $7700.00 | Window Closed / Lapsed |