US3787308A
Expired / Lapsed
US
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Oxygen sensor
Assignee: ESB Inc
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Filing: 1972-02-16
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Granted: 1974-01-22
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Expires: 1992-02-16
Abstract
Abstract A comparator element for gaseous oxygen comprises a first and a second oxygen-inert metal electrochemical cell. The first cell is fed with an oxygen containing gas of known oxygen content and the second cell is fed with a gas of unknown oxygen content. The design of the electrochemical cells is such that their electrical resistance when current is passed therethrough is inversely proportional to the oxygen content of the feed gas over a useful range. By comparing the resistances of the two cells, an accurate determination of the oxygen content of the unknown gas may be made with self compensation for ambient temperature. The range of the instrument may be increased by restricting the flow of gas to the oxygen electrodes. This may be accomplished by flowing the gas through a diffusion membrane and an orifice. Oxygen evolved from the metal electrode of the standard cell may be used to feed the oxygen electrode of the same cell thus providing a self sustaining standard atmosphere. The comparator may be compensated for pressure by providing pressure equalizing means between the gas feed to the first cell and the gas feed to the second.
Inventors
- 👤 F Malaspina
- 👤 W Aker
- 👤 J Werth
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 09:20
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/26; G01N27/403; G01N27/404
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
59 words
A comparator as defined in claim 1 including a first and a second means for restricting gas flow, the first means for restricting gas flow restricting the flow of gas to the cathode of the first electrochemical cell and the second means for restricting gas flow restricting the flow of gas to the cathode and the second electrochemical cell.
Claim 2
Dependent Claim
45 words
A comparator as defined in claim 2 wherein the first means for restricting the flow of gas to the first cathode includes a first diffusion membrane and the second means for restricting the flow of gas to the second cathode includes a second diffusion membrane.
Claim 3
Dependent Claim
48 words
A comparator as defined in claim 3 wherein the material from which the first and the second diffusion membranes are made is selected from the group which consists of natural rubber, silicone rubber, polytetrafluoroethylene, fluorinated ethylene-propylene co-polymer, polybutadiene, poly(butadiene-styrene), ethyl cellulose, cellulose acetate, and protein enriched triacetate cellulose.
Claim 4
Dependent Claim
43 words
A comparator as defined in claim 2 wherein the first means for restricting the flow of gas to the first cathode includes a first orifice and the second means for restricting the flow of gas to the second cathode includes a second orifice.
Claim 5
Dependent Claim
28 words
A comparator as defined in claim 1 including conduit means foR conducting oxygen gas given off by the anode of the first electrochemical cell to the cathode thereof.
Claim 6
Dependent Claim
27 words
A comparator as defined in claim 6 including means equalizing the pressure within the first electrochemical resistance cell to the pressure within the second electrochemical resistance cell.
Claim 7
Dependent Claim
65 words
A comparator as defined in claim 1 wherein each oxygen gas consuming cathode comprises a laminate of metallic grid, a porous sheet of carbon and polytetrafluoroethylene, and a sheet of microporous polytetrafluoroethylene, the side of the laminate bearing the grid being exposed to the electrolyte of the cell and the side of the laminate bearing the microporous sheet being exposable to an oxygen containing gas.
Claim 8
Dependent Claim
34 words
A comparator as defined in claim 1 wherein the means for comparing the resistance defined by the second drop with the resistance defined by the first drop comprises a four armed electrical bridge circuit.
Claim 9
Dependent Claim
44 words
A comparator element as defined in claim 1 wherein the inert metallic anode of the first electrochemical cell is a first side of a metallic anode and the inert metallic anode of the second electrochemical cell in the second side of said metallic anode.
Claim 10
Dependent Claim
233 words
An oxygen meter for determining the oxygen concentration of a gas of unknown oxygen content which comprises: a. first electrochemical resistance cell comprising a first oxygen consuming cathode receiving a first gas of known oxygen concentration, a first electrolyte and an inert metallic gassing anode; b. a second electrochemical resistance cell comprising a second oxygen consuming cathode receiving a second gas of unknown oxygen concentration, a second electrolyte and an inert metallic gassing anode; c. a housing containing the first electrochemical cell and the second electrochemical cell; d. means for supplying a positive current to the cathode of the first electrochemical cell to produce a first resistive drop across the first electrochemical cell the first drop being dependent upon the oxygen concentration of the first gas; e. means for supplying a positive current to the cathode of the second electrochemical cell to produce a second resistive drop across the second electrochemical cell the second drop being dependent upon the oxygen concentration of the second gas; f. means for supplying an equal and predetermined positive potential to the cathode of the first electrochemical cell and to the cathode of the second electrochemical cell; g. means for measuring the flow of current to the cathode of the second electrochemical cell; and h. calibration means for directly relating the magnitude of the flow of current to the oxygen concentration of the gas of unknown oxygen content.
Claim 11
Dependent Claim
60 words
An oxygen meter as defined in claim 11 including a first and a second means for restricting gas flow, the first means for restricting gas flow restricting the flow of gas to the cathode of the first electrochemical cell and the second means for restricting gas flow restricting the flow of gas to the cathode of the second electrochemical cell.
Claim 12
Dependent Claim
46 words
An oxygen meter as defined in claim 12 wherein the first means for restricting the flow of gas to the first cathode includes a first diffusion membrane and the second means for restricting the flow of gas to the second cathode includes a second diffusion membrane.
Claim 13
Dependent Claim
49 words
An oxygen meter as defined in claim 13 wherein the material from which the first and the second diffusion membranes are made is selected from the group which consists of natural rubber, silicone rubber, polytetrafluoroethylene, fluorinated ethylene-propylene co-polymer, polybutadiene, poly(butadiene-styrene), ethyl cellulose, cellulose acetate, and protein enriched triacetate cellulose.
Claim 14
Dependent Claim
44 words
An oxygen meter as defined in claim 12 wherein the first means for restricting the flow of gas to the first cathode includes a first orifice and the second means for restricting the flow of gas to the second cathode includes a seCond orifice.
Claim 15
Dependent Claim
29 words
An oxygen meter as defined in claim 11 including conduit means for conducting oxygen gas given off by the anode of the first electrochemical cell to the cathode thereof.
Claim 16
Dependent Claim
28 words
An oxygen meter as defined in claim 16 including means equalizing the pressure within the first electrochemical resistance cell to the pressure within the second electrochemical resistance cell.
Claim 17
Dependent Claim
67 words
An oxygen meter as defined in claim 11 wherein each oxygen gas consuming cathode comprises a laminate of a metallic grid, a porous sheet of carbon and polytetrafluoroethylene, and a sheet of microporous polytetrafluoroethylene, the side of the laminate bearing the grid being exposed to the electrolyte of the cell and the side of the laminate bearing the microporous sheet being exposable to an oxygen containing gas.
Claim 18
Dependent Claim
35 words
An oxygen meter as defined in claim 11 wherein the means for supplying a positive potential includes an electrochemical battery, and the means for measuring the current flow including a four armed electrical bridge circuit.
Claim 19
Dependent Claim
44 words
An oxygen meter as defined in claim 11 wherein the inert metallic anode of the first electrochemical cell is a first side of a metallic anode and the inert metallic anode of the second electrochemical cell is the second side of said metallic anode.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-01-21 | 1977-07-23 | 1978-01-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-01-21 | 1981-07-23 | 1982-01-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-01-21 | 1985-07-23 | 1986-01-22 | $7700.00 | Window Closed / Lapsed |