US4132616A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Gas sensor
Assignee: City Technology Ltd
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Filing: 1977-03-08
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Granted: 1979-01-02
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Expires: 1997-03-08
Abstract
Abstract An electro-chemical sensor for the measurement of concentrations of gas or vapor in accordance with the limiting current principle and comprising an electrolytic cell having a sensing electrode, a counter electrode and an intervening body of electrolyte and also a restriction to the rate of access of gas or vapor to the sensing electrode. The improvement comprises said restriction being in the form of a gas-phase diffusion barrier including at least one narrow passage for the diffusion of gas. The gas-phase diffusion barrier may be in the form of a porous body, of which the permeability of the body may be more than twenty times greater than the diffusibility, but is preferably less than ten times the diffusibility and more preferably not more than 10% greater than the diffusibility. Alternatively the gas-phase diffusion barrier may be defined by a capillary. The capillary may be of plastics material and may be enclosed within an outer metal sheath of lesser co-efficient of expansion. The capillary may be connected in series with a porous body.
Inventors
- 👤 Anthony D. S. Tantram
- 👤 Michael J. Kent
- 👤 Alan G. Palmer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 19:34
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/26; G01N27/403; G01N27/404; G01N33/00; G01N33/0004; G01N33/0009; G01N33/0011
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
116 words
In an electro-chemical sensor for the measurement of concentrations of gas or vapour in accordance with the limiting current principle, said sensor comprising an electrolytic cell having a sensing electrode, a counter electrode and an intervening body of electrolyte and also including means restricting the rate of access of gas or vapour to said sensing electrode, the improvement wherein said restricting means comprises a gas-phase diffusion barrier defining at least one narrow passage for the diffusion of gas, said gasphase diffusion barrier including structure formed with capillary passage means, said structure being made of plastics material and further including an outer metal sheath being of lesser co-efficient of expansion than said plastics material of said structure.
Claim 2
Dependent Claim
116 words
In an electro-chemical sensor for the measurement of concentrations of gas or vapour in accordance with the limiting current principle, said sensor comprising an electrolytic cell having a sensing electrode, a counter electrode and an intervening body of electrolyte and also including means restricting the rate of access of gas or vapour to said sensing electrode, the improvement wherein said restricting means comprises a gas-phase diffusion barrier defining at least one narrow passage for the diffusion of gas, said gasphase diffusion barrier including structure formed with capillary passage means, said structure being made of plastics material and further including an outer metal sheath being of lesser co-efficient of expansion than said plastics material of said structure.
Claim 3
Dependent Claim
127 words
In an electro-chemical sensor for the measurement of concentrations of gas or vapour in accordance with the limiting current principle, said sensor comprising an electrolytic cell having a sensing electrode, a counter electrode and an intervening body of electrolyte and also including means restricting the rate of access of gas or vapour to said sensing electrode, the improvement wherein said restricting means comprises a porous body in series with capillary passage means, the porous body and the capillary passage means cooperating to provide a gas-phase diffusion barrier defining at least one narrow passage for the diffusion of the gas being sensed so that the gas being sensed remains in the gas phase throughout the process of transport from the gas mixture under test to the sensing electrode.
Claim 4
Dependent Claim
127 words
In an electro-chemical sensor for the measurement of concentrations of gas or vapour in accordance with the limiting current principle, said sensor comprising an electrolytic cell having a sensing electrode, a counter electrode and an intervening body of electrolyte and also including means restricting the rate of access of gas or vapour to said sensing electrode, the improvement wherein said restricting means comprises a porous body in series with capillary passage means, the porous body and the capillary passage means cooperating to provide a gas-phase diffusion barrier defining at least one narrow passage for the diffusion of the gas being sensed so that the gas being sensed remains in the gas phase throughout the process of transport from the gas mixture under test to the sensing electrode.
Claim 5
Dependent Claim
35 words
An electro-chemical sensor according to claim 2, said sensor being adapted for use with an electro-chemically reducible gas and in which said counter electrode is a consumable metal anode which is more noble than hydrogen.
Claim 6
Dependent Claim
15 words
An electro-chemical sensor according to claim 3 in which said anode is made of lead.
Claim 7
Dependent Claim
15 words
An electro-chemical sensor according to claim 3 in which said anode is made of cadmium.
Claim 8
Dependent Claim
20 words
An electro-chemical oxygen sensor according to claim 3 in which said sensing electrode is a cathode including a nickel mesh.
Claim 9
Dependent Claim
23 words
An electro-chemical sensor according to claim 2 wherein said porous body has a permeability not more than twenty times greater than its diffusability.
Claim 10
Dependent Claim
23 words
An electro-chemical sensor according to claim 2 wherein said porous body has a permeability which is less than ten times the diffusability thereof.
Claim 11
Dependent Claim
25 words
An electro-chemical sensor according to claim 2 wherein said porous body has a permeability which is not more than 10% greater than the diffusability thereof.
Claim 12
Dependent Claim
31 words
An electro-chemical sensor according to claim 2 additionally including a porous membrane barrier in series with the restricting means and interposed between the gas mixture under test and the sensing electrode.
Claim 13
Dependent Claim
36 words
An electro-chemical sensor according to claim 2 wherein the porous body is arranged upstream from the capillary passage means along a path of flow normally followed by the gas or vapour in reaching said sensing electrode.
Claim 14
Dependent Claim
24 words
An electro-chemical sensor according to claim 2 wherein the sensing electrode together with the restricting means are fixed and sealed into a supporting housing.
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) | 1982-01-01 | 1982-07-03 | 1983-01-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-01-01 | 1986-07-03 | 1987-01-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-01-01 | 1990-07-03 | 1991-01-02 | $7700.00 | Window Closed / Lapsed |