EP0259175A2
Expired / Lapsed
EP
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Electrochemical gas sensor, and method for manufacturing the same
Assignee: NGK Insulators Ltd
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Filing: 1987-09-04
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Granted: —
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Expires: 2007-09-04
Abstract
Abstract A gas sensor for a measurement gas in an external space has an electrochemical pumping cell having a planar solid electrolyte body (2), and first and second electrodes (10, 12) which are disposed on opposite surfaces of the solid electrolyte body (2). The sensor has a gas-tight ceramic body (4) cooperating with the solid electrolyte body (2), to define therebetween a thin flat space (6), such that the first electrode (10) communicates with the thin flat space (6). The thin flat space (6) extends in a direction parallel to a plane of the planar solid electrolyte body (2) and has a predetermined diffusion resistance to the measurement gas. The sensor further includes a porous structure (8) exposed to the thin flat space (6) in a direction of thickness of the thin flat space. The porous structure is juxtaposed with respect to the first electrode (10) in the direction parallel to the plane of the solid electrolyte body, and maintains the thin flat space in communication with the external space under a predetermined diffusion resistance.
Inventors
- 👤 Hitoshi Iwakura-Danchi Nishizawa
- 👤 Kazuyoshi Ngk South Apartment Shibata
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-31 16:58
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/26; G01N27/416; G01N27/417; G01N27/403; G01N27/406; G01N27/407; G01N27/4071; G01N27/4072
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
180 words
A gas sensor for dealing with a measurement gas in an external space, comprising: an electrochemical pumping cell including a first planar solid electrolyte body, and a first electrode and a second electrode which are disposed on opposite surfaces of said first planar solid electrolyte body; a gas-tight ceramic body cooperating with said first planar solid electrolyte body, to define therebetween a thin flat space, such that said first electrode substantially communicates with said thin flat space, said thin flat space extending in a direction parallel to a plane of said first planar solid electrolyte body and having a first predetermined diffusion resistance to said measurement gas; and a porous structure exposed to said thin flat space in a direction of thickness of said thin flat space, and juxtaposed with respect to said first electrode in said direction parallel to the plane of said first planar solid electrolyte body, said porous structure having a second predetermined diffusion resistance to said measurement gas, and maintaining said thin flat space in communication with said external space under said second predetermined diffusion resistance.
Claim 2
Dependent Claim
180 words
A gas sensor for dealing with a measurement gas in an external space, comprising: an electrochemical pumping cell including a first planar solid electrolyte body, and a first electrode and a second electrode which are disposed on opposite surfaces of said first planar solid electrolyte body; a gas-tight ceramic body cooperating with said first planar solid electrolyte body, to define therebetween a thin flat space, such that said first electrode substantially communicates with said thin flat space, said thin flat space extending in a direction parallel to a plane of said first planar solid electrolyte body and having a first predetermined diffusion resistance to said measurement gas; and a porous structure exposed to said thin flat space in a direction of thickness of said thin flat space, and juxtaposed with respect to said first electrode in said direction parallel to the plane of said first planar solid electrolyte body, said porous structure having a second predetermined diffusion resistance to said measurement gas, and maintaining said thin flat space in communication with said external space under said second predetermined diffusion resistance.
Claim 3
Dependent Claim
50 words
A gas sensor according to claim 1, wherein said porous structure fills an aperture formed in at least one of said first planar solid electrolyte body and said gas-tight ceramic body, said porous structure being co-fired with said at least one of said solid electrolyte body and said ceramic body.
Claim 4
Dependent Claim
48 words
A gas sensor according to claim 1, wherein said first diffusion resistance of said thin flat space is within a range between 2% and 50% of an overall diffusion resistance which is a sum of said first diffusion resistance and said second diffusion resistance of said porous structure.
Claim 5
Dependent Claim
50 words
A gas sensor according to claim 1, further comprising an electrochemical sensing cell including a second planar solid electrolyte body, and a third electrode and a fourth electrode which are formed on said second planar solid electrolyte body, such that said third electrode substantially communicates with said thin flat space.
Claim 6
Dependent Claim
24 words
A gas sensor according to claim 4, wherein said second planar solid electrolyte body constitutes at least a portion of said gas-tight ceramic body.
Claim 7
Dependent Claim
24 words
A gas sensor according to claim 4, wherein said second planar solid electrolyte body constitutes a portion of said first planar solid electrolyte body.
Claim 8
Dependent Claim
39 words
A gas sensor according to claim 4, wherein said third electrode is spaced from said porous structure in said direction parallel to said plane of said first planar solid electrolyte body, by a larger distance than said first electrode.
Claim 9
Dependent Claim
43 words
A gas sensor according to claim 1, wherein said porous structure is a laminar structure consisting of a plurality of porous layers which have different porosities and which are superposed on each other in said direction of thickness of said thin flat space.
Claim 10
Dependent Claim
55 words
A gas sensor according to claim 1, wherein said porous structure is a laiminar structure consisting of a plurality of porous layers superposed on each other in said direction of thickness of said thin flat space, said laminar structure having at least one air gap between adjacent porous layers of said plurality of porous layers.
Claim 11
Dependent Claim
43 words
A gas sensor according to claim 1, wherein said porous structure, said thin flat space and said first electrode have a columnar, a disc-like and an annular shape, respectively, and said annular first electrode is disposed radially outwardly of said columnar porous structure.
Claim 12
Dependent Claim
46 words
A gas sensor according to claim 1, wherein said porous structure is formed of a material whose major component is the same as a major component of a material of which one of said first planar solid electrolyte body and said gas-tight ceramic body is formed.
Claim 13
Dependent Claim
52 words
A gas sensor according to claim 1, wherein said porous structure is a one-piece ceramic body which consists of a protrusion filling an aperture formed in said first planar solid electrolyte body, and a protective layer having a predetermined thickness covering said second electrode disposed on said first planar solid electrolyte body.
Claim 14
Independent Claim
307 words
A method manufacturing a gas sensor for dealing with a measurement gas in an external space, which gas sensor includes (a) an electrochemical pumping cell including a first planar solid electrolyte body, and a first electrode and a second electrode which are disposed on opposite surfaces of said first planar solid electrolyte body, (b) a gas-tight ceramic body cooperating with said first planar solid electrolyte body, to define therebetween a thin flat space, such that said first electrode substantially communicates with said thin flat space, said thin flat space extending in a direction parallel to a plane of said first planar solid electrolyte body and having a first predetermined diffusion resistance to said measurement gas, and (c) a porous structure exposed to said thin flat space in a direction of thickness said thin flat space, and juxtaposed with respect to said first electrode in said direction parallel to the plane of said first planar solid electrolyte body, said porous structure having a second predetermined diffusion resistance to said measurement gas, and maintaining said thin flat space in communication with said external space under said second predetermined diffusion resistance, said method comprising the steps of: preparing a first green sheet which gives said first planar solid electrolyte body, and a second green sheet which gives said gas-tight ceramic plate, and forming an aperture in at least one of said first and second green sheets; forming a ceramic green body which gives said porous structure, and inserting the formed ceramic green body into said aperture formed in each of said at least one of the first and second green sheets; and superposing said first and second green sheets one on the other, pressing the superposed first and second green sheets toward each other under heat, and firing the pressed first and second green sheets into a fired one-piece structure.
Claim 15
Independent Claim
307 words
A method manufacturing a gas sensor for dealing with a measurement gas in an external space, which gas sensor includes (a) an electrochemical pumping cell including a first planar solid electrolyte body, and a first electrode and a second electrode which are disposed on opposite surfaces of said first planar solid electrolyte body, (b) a gas-tight ceramic body cooperating with said first planar solid electrolyte body, to define therebetween a thin flat space, such that said first electrode substantially communicates with said thin flat space, said thin flat space extending in a direction parallel to a plane of said first planar solid electrolyte body and having a first predetermined diffusion resistance to said measurement gas, and (c) a porous structure exposed to said thin flat space in a direction of thickness said thin flat space, and juxtaposed with respect to said first electrode in said direction parallel to the plane of said first planar solid electrolyte body, said porous structure having a second predetermined diffusion resistance to said measurement gas, and maintaining said thin flat space in communication with said external space under said second predetermined diffusion resistance, said method comprising the steps of: preparing a first green sheet which gives said first planar solid electrolyte body, and a second green sheet which gives said gas-tight ceramic plate, and forming an aperture in at least one of said first and second green sheets; forming a ceramic green body which gives said porous structure, and inserting the formed ceramic green body into said aperture formed in each of said at least one of the first and second green sheets; and superposing said first and second green sheets one on the other, pressing the superposed first and second green sheets toward each other under heat, and firing the pressed first and second green sheets into a fired one-piece structure.
Claim 16
Independent Claim
306 words
A method of manufacturing a gas sensor for dealing with a measurement gas in an external space, which gas sensor includes (a) an electrochemical pumping cell including a first planar solid electrolyte body, and a first electrode and a second electrode which are disposed on opposite surfaces of said first planar solid electrolyte body, (b) a gas-tight ceramic body cooperating with said first planar solid electrolyte body, to define therebetween a thin flat space, such that said first electrode substantially communicates with said thin flat space, said thin flat space extending in a direction parallel to a plane of said first planar solid electrolyte body and having a first predetermined diffusion resistance to said measurement gas, and (c) a porous structure exposed to said thin flat space in a direction of thickness of said thin flat space, and juxtaposed with respect to said first electrode in said direction parallel to the plane of said first planar solid electrolyte body, said porous structure having a second predetermined diffusion resistance to said measurement gas, and maintaining said thin flat space in communication with said external space under said second predetermined diffusion resistance, said method comprising the steps of: preparing a first green sheet which gives said first planar solid electrolyte body, and a second green sheet which gives said gas-tight ceramic plate, and forming an aperture in at least one of said first and second green sheets; preparing a ceramic paste which gives said porous structure, and filling said aperture formed in each of said at least one of the first and second green sheets, with said ceramic paste; and superposing said first and second green sheets one on the other, pressing the superposed first and second green sheets toward each other under heat, and firing the pressed first and second green sheets into a fired one-piece structure.
Claim 17
Independent Claim
306 words
A method of manufacturing a gas sensor for dealing with a measurement gas in an external space, which gas sensor includes (a) an electrochemical pumping cell including a first planar solid electrolyte body, and a first electrode and a second electrode which are disposed on opposite surfaces of said first planar solid electrolyte body, (b) a gas-tight ceramic body cooperating with said first planar solid electrolyte body, to define therebetween a thin flat space, such that said first electrode substantially communicates with said thin flat space, said thin flat space extending in a direction parallel to a plane of said first planar solid electrolyte body and having a first predetermined diffusion resistance to said measurement gas, and (c) a porous structure exposed to said thin flat space in a direction of thickness of said thin flat space, and juxtaposed with respect to said first electrode in said direction parallel to the plane of said first planar solid electrolyte body, said porous structure having a second predetermined diffusion resistance to said measurement gas, and maintaining said thin flat space in communication with said external space under said second predetermined diffusion resistance, said method comprising the steps of: preparing a first green sheet which gives said first planar solid electrolyte body, and a second green sheet which gives said gas-tight ceramic plate, and forming an aperture in at least one of said first and second green sheets; preparing a ceramic paste which gives said porous structure, and filling said aperture formed in each of said at least one of the first and second green sheets, with said ceramic paste; and superposing said first and second green sheets one on the other, pressing the superposed first and second green sheets toward each other under heat, and firing the pressed first and second green sheets into a fired one-piece structure.
References Cited (Backward Citations)
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