US4406770A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Gas sensor
Assignee: City Technology Ltd
•
Filing: 1982-02-01
•
Granted: 1983-09-27
•
Expires: 2002-02-01
Abstract
Abstract A gas sensor cell assembly has planar electrodes separated by a planar hydrophilic wick which extends through the electrode into an electrolyte expansion chamber where it contacts an electrolyte. The cell is extremely compact and operates in all orientations.
Inventors
- 👤 Yat S. Chan
- 👤 Anthony D. S. Tantram
- 👤 Bryan S. Hobbs
- 👤 John R. Finbow
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 03:58
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/26; G01N27/403; G01N27/404; G01N27/4045; G01N33/00; G01N33/0004; G01N33/0009; G01N33/0011
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
151 words
A planar electrochemical cell gas sensor comprising a first planar (sensing) electrode, a first plastics housing part having a diffusion barrier capable of permitting a gaseous atmosphere to be sensed to diffuse to contact said first planar (sensing) electrode, a second plastics housing part having an electrolyte chamber formed therein, a second planar (counter) electrode carried on a planar support, said support having a hole or slit therein, a planar hydrophilic non-conducting porous separator interposed between said first and second electrodes and in contact therewith, and a hydrophilic non-conducting porous wick in contact with said separator, said wick passing through said opening in said counter electrode and said hole or slit in said planar support and extending into said electrolyte chamber, said electrolyte chamber being partially filled with an electrolyte that contacts said wick and provides an electrolytic connection between the sensing and counter electrodes in all orientations of the sensor.
Claim 2
Dependent Claim
151 words
A planar electrochemical cell gas sensor comprising a first planar (sensing) electrode, a first plastics housing part having a diffusion barrier capable of permitting a gaseous atmosphere to be sensed to diffuse to contact said first planar (sensing) electrode, a second plastics housing part having an electrolyte chamber formed therein, a second planar (counter) electrode carried on a planar support, said support having a hole or slit therein, a planar hydrophilic non-conducting porous separator interposed between said first and second electrodes and in contact therewith, and a hydrophilic non-conducting porous wick in contact with said separator, said wick passing through said opening in said counter electrode and said hole or slit in said planar support and extending into said electrolyte chamber, said electrolyte chamber being partially filled with an electrolyte that contacts said wick and provides an electrolytic connection between the sensing and counter electrodes in all orientations of the sensor.
Claim 3
Dependent Claim
50 words
The sensor of claim 1 further comprising a capillary gas vent connecting said electrolyte chamber and the ambient atmosphere, said vent being closed on the electrolyte side thereof by a hydrophobic porous membrane capable of permitting diffusion of gas to accomodate changes in pressure but preventing the passage of electrolyte.
Claim 4
Dependent Claim
14 words
A sensor as claimed in claim 1, additionally comprising a third planar (reference) electrode.
Claim 5
Dependent Claim
21 words
A sensor as claimed in claim 3, wherein the reference electrode is in substantially the same plane as the counter electrode.
Claim 6
Dependent Claim
29 words
A sensor as claimed in claim 4, wherein the reference electrode and the counter electrode are carried on a common planar support but are electronically isolated from each other.
Claim 7
Dependent Claim
54 words
A sensor as claimed in claim 3, wherein the reference electrode is in a different plane to that of the counter electrode and is separated therefrom by a further planar hydrophilic non-conducting porous separator which is in contact with the wick, the wick passing through an opening in the plane of the further separator.
Claim 8
Dependent Claim
22 words
A sensor as claimed in claim 3, wherein the reference electrode is an oxygen-water couple electrode receiving its oxygen from ambient air.
Claim 9
Dependent Claim
41 words
A sensor as claimed in claim 7, wherein one or both of the counter electrode and reference electrode are carried on a hydrophobic porous support which extends to the surface of the assembly and permits oxygen to diffuse to the electrode.
Claim 10
Dependent Claim
38 words
A sensor as claimed in claim 3, additionally comprising means for maintaining a current between the sensing electrode and the reference electrode and means for adjusting the current in order to adjust the base line of the sensor.
Claim 11
Dependent Claim
72 words
A sensor as claimed in claim 3, comprising a resistor, having a first side connected to the sensing electrode and means to control and maintain a constant potential between the second side of the resistor and the reference electrode, whereby a signal equal to the change in potential of the sensing electrode on exposure to the gas to be detected and giving a measure of its concentration is developed across said resistor.
Claim 12
Dependent Claim
30 words
A sensor as claimed in claim 1, wherein one or more of the electrodes comprises a catalyst mixed with PTFE particles bonded to a porous unsintered PTFE tape planar support.
Claim 13
Dependent Claim
32 words
A sensor as claimed in claim 11, wherein one or more of the electrodes is a catalyst selected from platinum, iridium, ruthenium, osmium, palladium, gold, silver, carbon and mixtures or alloys thereof.
Claim 14
Dependent Claim
22 words
A sensor as claimed in claim 1, wherein the sensing electrode is an anode for the detection and measurement of oxidisable gases.
Claim 15
Dependent Claim
22 words
A sensor as claimed in claim 13, wherein the counter electrode is an oxygen reduction cathode receiving its oxygen from ambient air.
Claim 16
Dependent Claim
22 words
A sensor as claimed in claim 1, wherein the sensing electrode is a cathode for the detection and measurement of reducible gases.
Claim 17
Dependent Claim
21 words
A sensor as claimed in claim 1, wherein the diffusion barrier is selected from capillary, porous membrane, and non-porous plastics film.
Claim 18
Dependent Claim
44 words
A sensor as claimed in claim 16, wherein a capillary is used which is formed by a capillary insert in the sensor assembly and the material of the insert has a higher coefficient of thermal expansion than the material into which it is inserted.
References Cited (Backward Citations)
US3325378A
Cited
US3577332A
Cited
US3776832A
Cited
US3824167A
Cited
US3755125A
Cited
US3886058A
Cited
US4132616A
Cited
US4126531A
Cited
US4324632A
Cited
GB2075197A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-09-26 | 1987-03-28 | 1987-09-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-09-26 | 1991-03-28 | 1991-09-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-09-26 | 1995-03-28 | 1995-09-27 | $7700.00 | Window Closed / Lapsed |