GB2176900A - Solid electrolyte gas sensor - Google Patents

Solid electrolyte gas sensor Download PDF

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Publication number
GB2176900A
GB2176900A GB08611054A GB8611054A GB2176900A GB 2176900 A GB2176900 A GB 2176900A GB 08611054 A GB08611054 A GB 08611054A GB 8611054 A GB8611054 A GB 8611054A GB 2176900 A GB2176900 A GB 2176900A
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United Kingdom
Prior art keywords
phase
measuring
ionic conductor
detection
partial pressure
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GB2176900B (en
GB8611054D0 (en
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Gerhard-Ludwig Schlechtriemen
Werner Weppner
Gerhard Hotzel
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Draegerwerk AG and Co KGaA
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Draegerwerk AG and Co KGaA
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/26—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
    • G01N27/403—Cells and electrode assemblies
    • G01N27/406—Cells and probes with solid electrolytes
    • G01N27/407—Cells and probes with solid electrolytes for investigating or analysing gases
    • G01N27/4073—Composition or fabrication of the solid electrolyte
    • G01N27/4074—Composition or fabrication of the solid electrolyte for detection of gases other than oxygen

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  • Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Molecular Biology (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Measuring Oxygen Concentration In Cells (AREA)

Abstract

A method for measuring the partial pressure of a constituent of a gas mixture uses a solid ionic conductor, which contains several constituents, in contact, on one side, with a reference phase and, on the other side, with a phase which is sensitive to the constituent of the gas mixture. The solid ionic conductor has at least one constituent whose activity is substantially unaffected by the constituent to be detected so that the number of adjacent phases required to produce the phase equilibrium for the ionic conductor is reduced on the measuring side. Electrodes for deriving a potential difference corresponding to the gas partial pressure, are connected with the reference phase and with the sensitive phase. An intermediate layer may be located between the ionic conductor and the phase which is sensitive to the constituent gas. Sensors for chlorine, oxygen, nitrogen oxides and carbon oxides are described using electrolytes comprising substituted beta-alumin as or silver rubidium iodide.

Description

SPECIFICATION An apparatus for and a method of measuring the activity of a constituent of a medium This invention relates to an apparatus for and a method of measuring the activity of a constituent of a medium, and more particularly to an apparatus for and method of measuring the partial pressure of one constituent in a gas mixture. The method uses a solid ionic conductor which contains several constituents and which is connected, on one side, with a reference phase and, on the other side, with a phase which is sensitive to the constituent which is to be detected, the sensitive phase being in equilibrium with a number of adjacent phases necessary for the detection.Measurements are made using deriving electrodes, connected with the reference phase and with the sensitive phase, between which there is produced a potential difference corresponding to the activity or the partial pressure of the constituent to be detected, the constituents of the solid ionic conductor being in equilibrium with each other and the ionic conductor itself being in phase-equilibrium with the reference phase.
In German Offenlegungsschrift 29 26 172, there is described a method for measuring the activity of a constituent of a medium with the aid of a solid ionic conductor with N constituents (N 3) of which one constituent corresponds with the constituent which is to be measured. This ionic conductor is brought into equilibrium, on the one hand, with the medium to be measured and N-2 adjacent phases of the phase system of the N constituents of the ionic conductor and, on the other hand, with a reference electrode. The voltage between this reference electrode and a phase which is sensitive to the constituent of the medium to be detected is measured as a measure of the activity.With such a system, in order to keep essentially all degrees of freedom of the system present in the determined state of equilibrium, it is necessary, in addition to the medium to be measured as a first phase, to bring N-2 adjacent phases for the medium to be measured into contact with the ionic conductor on the measuring side.
The present invention seeks to avoid the disadvantage of the known method, described above, by reducing the number of adjacent phases, on the measuring side, which must be brought into contact with the solid ionic conductor to produce phase equilibria.
This is achieved by providing that the solid ionic conductor has at least one component whose activity is substantially unaffected by the constituent which is to be detected.
According to one aspect of the present invention, there is provided an apparatus for measuring the activity of a constituent of a medium, the apparatus comprising: a solid ionic conductor having a plurality of ionic components, the solid ionic conductor being in communication with a reference phase and with a detection phase, said detection phase being sensitive to said constituent whose acitivity is to be measured and the solid ionic conductor including a first ionic component which is substantially unaffected by the presence of the constituent whose activity is to be measured; and means for measuring the potential difference between the reference phase and the detection phase.
Preferably, the apparatus also comprises a pair of electrodes, a first electrode being in contact with the reference phase, and a second electrode being in contact with the detection phase.
In some preferred embodiments, the solid ionic conductor has a lattice structure in which the first ionic component is constrained.
Additionally or alternatively, there may be provided an intermediate layer, located between the detection phase and the reference phase.
According to a second aspect of the present invention, there is provided a method for measuring the activity of a constituent of a medium, the method employing an apparatus comprising: a solid ionic conductor having a plurality of ionic components, the solid ionic conductor being in communication with a reference phase and with a detection phase, said detection phase being sensitive to said constituent whose activity is to be measured and the solid ionic conductor including a first ionic component which is substantiallly unaffected by the presence of the constituent whose activity is to be measured; and means for measuring the potential difference between the reference phase and the detection phase, and the method comprising the steps of: exposing to the medium the detection phase of said apparatus; and measuring the potential difference produced between the reference phase and the detection phase.
In the apparatus and method according to the invention, the ionic conductor is brought, by way of direct contact with 3 N-3 adjacent phases (or 3 N-2 adjacent phases if the ionic conductor does not contain the constituent to be determined) on the measuring side, and by way of a corresponding sensitive phase, into quasi-equilibrium with the medium containing the constituent whose activity is to be determined. On the other side, the ionic conductor is in contact with a reference phase to determine the activity of the ion species which may be moved in the ionic conductor at the phase boundary which develops through this contact point.Thus, the measurable variable is the potential difference, between two deriving electrodes, connected with the reference phase and with the sensitive phase respectively, which is to be ascertained when no current is flowing. In contrast to the previously known method, there is no fuily determined state of equilibrium in this case, but the constituent whose activity is substantially unaffected by the constituent to be detected is in quasi-equilibrium with the other constituents.
Basically, two different developments of the method are possible. The solid ionic conductor can thus advantageously be built up, in terms of its lattice structure, as a chemical compound, such that at least one of its constituents forms the substantially unaffected constituent, because its mobility in the lattice is restricted by strong interionic forces. In these cases, in which there is a quasi-equilibrium situation by virtue of the chemical composition of the ionic conductor, the thermodynamic activity of one or several constituents of the ionic conductor is essentially fixed in the whole range of activity of the constituent whose activity is to be determined. A development of this kind results in a saving, at least in terms of those adjacent phases with which the ionic conductor ought to be brought into contact for the purpose of establishing a defined state of equilibrium.In this way a simplication of the whole structure is achieved.
An alternative advantageous development can provide that an intermediate layer is arranged between the solid ionic conductor and the sensitive phase, so that the coupling-in of the activity of the constituent which is to be detected, determining the potential, takes place without a chemical reaction between the solid ionic conductor and the sensitive phase.An advantage of providing an intermediate layer of this kind is that the number of possibilities for combining ionic conductors with gas-sensitive phases is increased, in so far as thermo-dynamically unstable phase boundaries, which can exist when some potentially useful combinations of ionic conductor and sensitive electrode material are brought into immediate proximity, may be eiiminated as a result of the insertion of one or more auxiliary phases, with the development of an intermediate layer between the ionic conductor and the gas-sensitive phase.
The general principle of the invention, which can be realized in the two ways mentioned above, holds good, essentially, for ionic conductors with any number N of constituents. The principie is explained below in respect of galvanic solid chains with ternary solid electrolytes, as these, on account of the comparatively simple structure of the resultant galvanic cell, are of most technical significance.
With ternary solid ionic conductors, i.e. ionic conductors with 3 constituents, when using the method of the present invention, the number of adjacent phases which, on the measuring side, are in contact with the ionic conductor, is at most one, if the constituent whose activity is to be measured is identical with none of the three constituents of the ionic conductor.The phase sequence of the galvanic chains can be diagrammatically represented for the two principles of solution [a) immobility conditional on crystal structure and b) intermediate layer] as follows: a) deriving reference ternary gas- deriving electrode electrode ionic sensitive electrode conductor phase measuring medium b) deriving reference ternary inter- gas- deriving electrode electrode ionic mediate sensitive electrode conductor layer; phase measuring adjacent medium phase The potential difference across these chains, arising as a measurable variable, is linked by way of the Nernst equation with the activity ratio of the movable ion species of the solid electrolyte on both sides (' and ') of the same, a constant activity being preset in both cases on th reference side.On the measuring side the activity is determined by coupling the constituent whose activity is to be detected to the sensitive phase. For the purpose of stabilizing the thermodynamically and, more particularly, the kinetically unstable phase boundaries between ionic conductor and gas-sensitive phase, in the case of the special development of the sytem (with intermediate layer suppressing the chemical reaction) on the measuring side an adjacent phase of such a kind is brought into direct contact with the ionic conductor that at this point a thermodynamically stable phase boundary develops. On the other side of this intermediate layer, which acts as a blocking layer, there is the sensitive phase which, at its junction with the intermediate layer, likewise develops a thermodynamically stable phase boundary.As a result of this configuration, the direct contact between ionic conductor and the sensitive phase is avoided, as the immediate juxtaposition of the two phases would result in a chemical reaction between them. Instead of the desired development of a temporally stable state of quasi-equilibrium, there would then be a non-equilibrium situation, in which no reproducable, stable relationships would exist on the measuring electrode side.
For the intermediate layer, an ion-conducting compound may advantageously be chosen, the movable ions of which compound correspond with those of the solid ionic conductor, such that the activities of the constituents from the sensitive phase, which are established through the activity of the constituent which is to be determined, and more particularly through the partial pressure of the gas which is to be measured, can be coupled by way of the contact of the intermediate layer to the ionic conductor.
Advantageous variants of the method are explained in the following examples, which may be used for determining chlorine partial pressure, for determining COx-partial pressure, for determining NOx-partial pressure and for determining O2-partial pressure. X may be 1 or 2.
I. Galvanic solid chain for measuring chlorine partial pressure Deriving electrode Ag Ag-p-alumina AgCI Deriving electrode Gas, Pc2 Silver-substituted p-alumina (synonym: silver-p-alumina), which has practically pure silver ionic conduction, is used as a solid electrolyte (Y.-F.Y. Yao, J.T. Kummer, J. Inorg.Nucl.Chem. 1967, 29, 2453). For the purpose of fixing, on the reference side, the activity of the silver in the silver-p alumina, the ionic conductor is in contact there with a reference phase of pure silver or with a closed AgCI layer to which an Ag-layer is connected.This latter, alternative, way of realizing the reference phase is of importance as, if the reference phase consists just of silver and if, for example, by virtue of the porosities of the electrolyte ceramics or for some other reason, the gas of interest containing C12 can reach the reference phase, then AgCI will be formed locally as a result of a reaction of the elementary silver with the chlorine. As a result of this, the ionic conductor would no longer be in equilibrium with a defined invariant reference phase, this becoming apparent in a temporal instability of the voltage measured between the deriving electrodes.
The idea of a double layer reference electrode built up in this way can accordingly also be used for other systems. Instead of the pure metal, binary alloys containing the metal may also be used advantageously in equilibrium with a further phase of the 2-constituent system, which contains at least one of the metals in the alloy.
Another structure, which might be advantageous, can provide for the metal reference phase to exist together with a further phase which consists of a chemical compound between the metal of the reference phase and the constituent whose activity is to be determined.
The measuring medium, with a certain chlorine activity (which in the case of a gaseous measuring medium behaving in an approximately ideal manner, corresponds to the chlorine partial pressure), establishes, in the sensitive adjacent phase, with a thin layer of silver chloride located on the measuring side of the silver-p-alumina, in the specified arrangement, the chlorine activity and with that also, according to the Gibbs-Dunhem-Rule, the silver activity. Thus, produced at the phase boundary of the solid ionic conductor and the gas-sensitive thin layer there is a silver activity which is clearly linked with the chlorine activity in the measuring medium, and the value of which is expressed relative to the reference activity of the silver, in the silver in the measurable E.M.F..
Then, assuming that the temperature is constant along the chain, the E.M.F. is only a function of the chlorine partial pressure. Silver-p-alumina can, on account of the structurally-dependent fixing of the aluminium activity, be considered as a pseudo-ternary or quasi-binary compound with the thermodynamically active constituents being silver and oxygen. This galvanic chain may thus be used as a chlorine sensor, and, on account of the silver ionic conductivity of the solid electrolyte which is already sufficiently high at room temperature, may be used in this comparatively low temperature range.
II. Galvanic solid chain, with intermediate layer, for measuring chlorine partial pressures Deriving electrode Ag Ag4Rbis Agl AgCI Deriving electrode inter- Gas, Pc2 mediate layer Silver rubidium iodide (B.B. Owens, G.R. Argue, Science, 157, 308) is a solid, and a silver ionic conductor at room temperature. Silver can preferably be used as a reference phase.On the measuring side, inserted between the thin, gas-sensitive silver chloride layer and the solid ionic conductor, there is a thin intermediate layer of silver iodide, which guarantees the stability of the arrangement and which transfers the activity of the silver in the silver chloride layer which is dependent on the chlorine partial pressure in the surrounding gas phase, from the silver chloride layer to the ionic conductor so that the electric potential difference, which may be measured between the deriving electrodes, is, at constant temperature, as in Example I, only dependent on the chloride partial pressure in the measuring medium.
As to the physical realisation of the solid electrolyte sensors suitable for partial pressure measurement, the techniques known for the thin or thick layer technology are advantageously used to achieve a miniaturization of the arrangements. The prior art with regard to the application of such technologies for producing so-called micro-ionic components is described in, for example, G. Gelasco, Solid State lonics 9-10, 783 (1983).
Further examples of galvanic solid chains according to the invention are: III. Galvanic solid chains for determining COx-partial pressure 1.) Deriving Na/ Na-ss- Na2CO3 Deriving electrode electrode Na-alloy alumina Gas, Pc'2 2.) Deriving Ag Ag-p- Ag2CO3 Deriving electrode electrode alumina Gas, Pcox 3.) Deriving Ag Ag4Rbl5 Ag4Rbis, Deriving electrode electrode Ag2CO2 Gas, PcOx IV.Galvanic solid chain, with intermediate layer, for determining COx-partial pressure Deriving Ag Ag4Rbl5 Ag Ag2CO3 Deriving electrode electrode inter- Gas, Pcax mediate V. Galvanic solid chains for determining NOx-partial pressure 1.) Deriving Ag Ag-p- AgNO3 or Deriving electrode electrode alumina ARNO, Gas, PNox 2.) Deriving Na/Na- Na-p- Na NO3 or Deriving electrode electrode alloy alumina NaNO2 Gas, PNOX VI. Galvanic solid chain, with intermediate layer, for determining NOx-partial pressure.
Deriving Ag Ag4Rbl5 Agl ARNO, Deriving electrode electrode inter- or Gas, PNox mediate ARNO, layer VII. Galvanic solid chains for determining O2-partial pressure 1.) Deriving Ag Ag-p- Ag2O Deriving electrode electrode alumina Gas, P02 2.) Deriving Na/Na- Na-p- Na2O Deriving electrode electrode alloy alumina Gas, P02

Claims (26)

1. An apparatus for measuring the activity of a constituent of a medium, the apparatus comprising: a solid ionic conductor having a plurality of ionic components, the solid ionic conductor being in communication with a reference phase and with a detection phase, said detection phase being sensitive to said constituent whose activity is to be measured and the solid ionic conductor including a first ionic component which is substantially unaffected by the presence of the constituent whose activity is to be measured; and means for measuring the potential difference between the reference phase and the detection phase.
2. An apparatus as claimed in claim 1, further comprising a pair of electrodes, a first electrode being in contact with the reference phase, and a second electrode being in contact with the detection phase
3. An apparatus as claimed in claim 1 or 2, wherein the solid ionic conductor has a lattice structure in which the first ionic component is constrained.
4. An apparatus as claimed in claim 1, 2 or 3, further comprising an intermediate layer, located between the reference phase and the detection phase.
5. An apparatus as claimed in claim 3, for measuring the partial pressure of chlorine in a gas mixture, wherein the solid ionic conductor comprises Ag-p-A12O2, the detection phase comprises AgCI, and the reference phase comprises Ag.
6. An apparatus as claimed in claim 4, for measuring the partial pressure of chlorine in a gas mixture, wherein the solid ionic conductor comprises Ag4Rbl5, the detection phase comprises AgCI, the intermediate phase comprises Agl, and the reference phase comprises Ag.
7. An apparatus as claimed in claim 3, for measuring the partial pressure of COx in a gas mixture, wherein the solid ionic conductor comprises Na-p-A12O3 and the reference phase comprises Na.
8. An apparatus as claimed in claim 3, for measuring the partial pressure of COx in a gas mixture, wherein the solid ionic conductor comprises Ag-p-A12O2, the detection phase comprises Ag2CO3, and the reference phase comprises Ag.
9. An apparatus as claimed in claim 4, for measuring the partial pressure of COx in a gas mixture, wherein the solid ionic conductor comprises Ag4Rbl5, the detection phase comprises Ag2CO3, the intermediate phase comprises Agl, and the reference phase comprises Ag.
10. An apparatus as claimed in claim 3, for measuring the partial pressure of COx in a gas mixture, wherein the solid ionic conductor comprises Ag4Rbl5, the detection phase comprises Ag2CO3 and Ag4Rbl5, and the reference phase comprises Ag.
11. An apparatus as claimed in claim 3, for measuring the partial pressure of NO in a gas mixture, wherein the solid ionic conductor comprises Ag -p-A12O2, the detection phase comprises ARNO, or Ago2, and the reference phase comprises Ag.
12. An apparatus as claimed in claim 3, for measuring the partial pressure of NO in a gas mixture, wherein the solid ionic conductor comprises Na -p-A12O3, the detection phase comprises Na NO2 or NaNO2 and the reference phase comprises Na.
13. An apparatus as claimed in claim 4, for measuring the partial pressure of NOX in a gas mixture, wherein the solid ionic conductor comprises Ag4Rbl5, the detection phase comprises ARNO, or AgNO2, the intermediate phase comprises Agl, and the reference phase comprises Ag.
14. An apparatus as claimed in claim 3, for measuring the partial pressure of oxygen in a gas mixture, wherein the solid ionic conductor comprises Ag -p-A12O2, the detection phase comprises Ag2O, and the reference phase comprises Ag.
15. An apparatus as claimed in claim 3, for measuring the partial pressure of oxygen in a gas mixture, wherein the solid ionic conductor comprises Na-p-A12O2, the detection phase comprises Na2O and the reference phase comprises Na.
16. An apparatus as claimed in any of claims 5 to 15, wherein the metal reference phase is replaced by a binary alloy of the metal in equilibrium with a further phase of this 2-constituent system which contains at least one of the metals in the alloy.
17. An apparatus as claimed in any of claims 5 to 15, wherein the metal reference phase exists together with a further phase which consits of a chemical compound containing the metal of the reference phase and the gas whose partial pressure is to be measured.
18. A method for producing a galvanic solid chain as claimed in any preceding claim, wherein the solid ionic conductor and the detection phase are applied to a substrate using thin-layer techniques.
19. A method for measuring the activity of a constituent of a medium, the method employing an apparatus comprising: a solid ionic conductor having a plurality of ionic components, the solid ionic conductor being in communication with a reference phase and with a detection phase, said detection phase being sensitive to said constituent whose activity is to be measured and the solid ionic conductor including a first ionic component which is substantially unaffected by the presence of the constituent whose activity is to be measured; and means for measuring the potential difference between the reference phase and the detection phase, and the method comprising the steps of: exposing to the medium the detection phase of said apparatus; and measuring the potential difference produced between the reference phase and the detection phase.
20. A method of measuring the activity of a constituent of a medium, comprising the steps of : exposing to the medium the detection phase of an apparatus according to one of claims 2 to 4; and measuring the potential difference produced between the reference phase and the detection phase.
21. A method of measuring the partial pressure of chlorine in a gas mixture comprising the steps of exposing to the gas mixture the detection phase of an apparatus according to one of claims 5 or 6, and measuring the potential difference produced between the reference phase and the detection phase.
22. A method of measuring the partial pressure of CO in a gas mixture comprising the steps of exposing to the gas mixture the detection of an apparatus according to one of claims 7 to 10, and measuring the potential difference produced between the reference phase and the detection phase.
23. A method of measuring the partial pressure of NO in a gas mixture comprising the steps of exposing to the gas mixture the detection of an apparatus according to one of claims 11 to 13, and measuring the potential difference produced between the reference phase and the detection phase.
24. A method of measuring the partial pressure of oxygen in a gas mixture comprising the steps of exposing to the gas mixture the detection of an apparatus according to one of claims 14 to 15, and measuring the potential difference produced between the reference phase and the detection phase.
25. A method for measuring the activity of a constituent of a medium or the partial pressure of a constituent of a gas mixture employing a solid ionic conductor which comprises at least two constituents and which is in communication with a reference phase and a phase which is sensitive to a component of the medium to be detected and which is also in equilibrium with a number of adjacent phases necessary for said detection, there being provided, connected between the reference phase and the sensitive phase, means for measuring the potential difference between the phases, which potential difference corresponds to the activity of the constituent to be detected or the gas partial pressure, the constituents of the solid ionic conductor being in equilibrium with each other and the ionic conductor being in phase-equilibrium with the reference phase, wherein the solid ionic conductor includes at least one constituent whose activity is substantially unaffected by the constituent to be detected, thereby reducing the number of adjacent phases required to produce the phase-equilibria for the ionic conductor on the measuring side.
26. An apparatus for, or a method of, measuring the activity of a constituent of a medium substantially as herein described.
GB8611054A 1985-05-07 1986-05-07 An apparatus for and a method of measuring the activity of a constituent of a medium Expired GB2176900B (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19853516315 DE3516315A1 (en) 1985-05-07 1985-05-07 METHOD FOR MEASURING THE ACTIVITY OF A COMPONENT OF A MEDIUM, IN PARTICULAR FOR PARTIAL PRESSURE MEASUREMENT OF A COMPONENT OF A GAS MIXTURE

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GB8611054D0 GB8611054D0 (en) 1986-06-11
GB2176900A true GB2176900A (en) 1987-01-07
GB2176900B GB2176900B (en) 1989-06-28

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JP (1) JPS61256252A (en)
DE (1) DE3516315A1 (en)
FR (1) FR2581762B1 (en)
GB (1) GB2176900B (en)

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US4842698A (en) * 1987-05-19 1989-06-27 Canadian Patents And Development Limited/Societe Canadienne Des Brevets Et D'exploitation Limitee Solid state arsenic probe for use in pyrometallurgical processes
EP1039292A2 (en) 1999-03-19 2000-09-27 Alphasense Limited Gas sensor

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Publication number Priority date Publication date Assignee Title
DE3529335A1 (en) * 1985-08-16 1987-02-26 Draegerwerk Ag SOLID CHAIN FOR ACTIVITY MEASUREMENT WITH FIXED ION CONDUCTOR
DE3620092A1 (en) * 1986-06-14 1987-12-17 Draegerwerk Ag GALVANIC SOLID CHAIN FOR MEASURING O (ARROW DOWN) 2 (ARROW DOWN) PARTIAL PRESSURE
DE3931235A1 (en) * 1989-09-19 1991-03-28 Max Planck Gesellschaft Solid electrolyte gas-sensor without ionic transfer - uses minority carrier transport to make it free of surface polarisation and able to operate at low temperature
DE19517907C1 (en) * 1995-05-16 1996-10-24 Auergesellschaft Gmbh Electrochemical solid electrolyte sensor for measuring chlorine

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GB1546427A (en) * 1975-08-29 1979-05-23 Hydro Quebec Solid state sensor for anhydrides
EP0078627A1 (en) * 1981-10-19 1983-05-11 Westinghouse Electric Corporation Improved solid electrolyte gas sensing apparatus

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GB1470558A (en) * 1974-07-03 1977-04-14 Nat Res Dev Method and apparatus for detecting elements
GB1521964A (en) * 1974-09-04 1978-08-23 Nat Res Dev Ion-sensitive electrodes
JPS55166040A (en) * 1979-06-13 1980-12-24 Nissan Motor Co Ltd Air fuel ratio detector
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GB2119933B (en) * 1982-05-06 1986-09-17 Atomic Energy Authority Uk Solid electrolyte gas sensors

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Publication number Priority date Publication date Assignee Title
GB1546427A (en) * 1975-08-29 1979-05-23 Hydro Quebec Solid state sensor for anhydrides
EP0078627A1 (en) * 1981-10-19 1983-05-11 Westinghouse Electric Corporation Improved solid electrolyte gas sensing apparatus

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4842698A (en) * 1987-05-19 1989-06-27 Canadian Patents And Development Limited/Societe Canadienne Des Brevets Et D'exploitation Limitee Solid state arsenic probe for use in pyrometallurgical processes
EP1039292A2 (en) 1999-03-19 2000-09-27 Alphasense Limited Gas sensor
EP1039292A3 (en) * 1999-03-19 2004-12-29 Alphasense Limited Gas sensor

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GB2176900B (en) 1989-06-28
GB8611054D0 (en) 1986-06-11
DE3516315C2 (en) 1988-02-18
FR2581762A1 (en) 1986-11-14
JPS61256252A (en) 1986-11-13
DE3516315A1 (en) 1986-11-13
FR2581762B1 (en) 1990-07-06

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Effective date: 19940507