CA1198345A - Sensor for determining the oxygen content in a gas - Google Patents
Sensor for determining the oxygen content in a gasInfo
- Publication number
- CA1198345A CA1198345A CA000415207A CA415207A CA1198345A CA 1198345 A CA1198345 A CA 1198345A CA 000415207 A CA000415207 A CA 000415207A CA 415207 A CA415207 A CA 415207A CA 1198345 A CA1198345 A CA 1198345A
- Authority
- CA
- Canada
- Prior art keywords
- sensor
- gas
- determining
- electrode coatings
- oxygen
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- 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
- G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
- G01N27/04—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance
- G01N27/12—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance of a solid body in dependence upon absorption of a fluid; of a solid body in dependence upon reaction with a fluid, for detecting components in the fluid
Abstract
ABSTRACT:
Sensor for determining the oxygen content in a gas.
A sensor for determining the oxygen content of a gas, the sensor consisting of a lozenge of stabilised bismuth trioxide provided on both sides with electrode coatings. The resistance between the electrode coatings is an oxygen partial pressure-dependent quantity. The lozenge is immersed entirely in the gas to be analysed;
the necessity of a reference gas is absent.
Sensor for determining the oxygen content in a gas.
A sensor for determining the oxygen content of a gas, the sensor consisting of a lozenge of stabilised bismuth trioxide provided on both sides with electrode coatings. The resistance between the electrode coatings is an oxygen partial pressure-dependent quantity. The lozenge is immersed entirely in the gas to be analysed;
the necessity of a reference gas is absent.
Description
3~
PIIN 10,195 1 1~0.1982 "Sensor ~or cIeterminlng the oxygen content in a gas~', The invention relates to a sensor ~or deter-m; n; ng the oxygen content in a gas~
Such sensors are known (for e~ample from DE-OS 2742278) in which a solid electrolyte which shows ion conductivity is used in the form of a par-ti-tion provided on both sides with electrode coatings, Gas having a known ox~gen content is present as a reference gas on one side of the partition7 and gas in which the oxygen is presen~ in an unknown concentration is present on the other side9 ~s a result of this a potential difference is established between -thc two el~ctrode coatings 9 which produces a current through the material which is transported by the oxygen ions in the solid electrolyte, This current has a valIle which is proportional to the ratio o~ -the oxygen concentrations on the two sides of the partition and hence the unknown oxygen concentration can thus be calculated~
The mobility of the ions in the solid electroly-te depends considerably on the tempera-ture and a consequen~
ce of this temperature dependence is that the oxygen
PIIN 10,195 1 1~0.1982 "Sensor ~or cIeterminlng the oxygen content in a gas~', The invention relates to a sensor ~or deter-m; n; ng the oxygen content in a gas~
Such sensors are known (for e~ample from DE-OS 2742278) in which a solid electrolyte which shows ion conductivity is used in the form of a par-ti-tion provided on both sides with electrode coatings, Gas having a known ox~gen content is present as a reference gas on one side of the partition7 and gas in which the oxygen is presen~ in an unknown concentration is present on the other side9 ~s a result of this a potential difference is established between -thc two el~ctrode coatings 9 which produces a current through the material which is transported by the oxygen ions in the solid electrolyte, This current has a valIle which is proportional to the ratio o~ -the oxygen concentrations on the two sides of the partition and hence the unknown oxygen concentration can thus be calculated~
The mobility of the ions in the solid electroly-te depends considerably on the tempera-ture and a consequen~
ce of this temperature dependence is that the oxygen
2~ determination also has a temperature~dependent sensi-tivity.
During the measurement the temperature of the solid electrol~yte in prac-tice mus-t at least be 250C, A disadvantage of this known type of oxygen sensor is that a re~erence gas having an oxygen concentra-2~ tion which is kept accurately constant is essential.
I-t is -the obJect of the invention to provide a sensor which operates without using such a reference gas.
According to the invention, the sensor of -the above-described type using a solid electrolyte wl~h ion 30 conductivity which is provided on both sides with electrode coatings is characterized in that the solid electrolyte consists o~ stabilised ~i203 in the form of a tablet which co~prises elec-trode coatings and is surrounded entirely by P'HN 'IO.'l95 2 'l.10.'l982 the gas to ~e ana:lyzed and -tha-t the resis-tance ~et-ween the elec-trocl,e coatings ls measured as an oxygen partial pressure-dependent quanti-ty.
The ~i2O3 is stabilised ln known manner by the addltion or yttrlum oxlcle, an o~ide of an elemen-t from the lanthanlcle group havlng an atomic number between 62 and 7O incl-uding the -terminal values niobium oxide, tanta-lum oxide or tungsten oxide, As a resul-t of stabilisation the material obtains a face~centred cu'bic lattice and only in this s-tructure can it be used as a sensor.
The operation of the sensor according to the invention is based on the variation of the electrode resistance as a function of the oxygen partial pressure.
By means o~ a direct current vol-tage the resistance of the eLectrode/electrolyte combina-tion is measured. For this it holds that:
electrode to-tal Uelectrolyte ~-Rtotal is the quant;ity to 'be measured;
Relec-trolyte and also I~ are quantities which are incdependent of the oxygen par-tial pressure and a known function o~ the temperature~ With -the choice of a deflni-te temperature9 both are constants. In this case also the 25 measurement mus-t thus be carried out at a particular tempe-rature which is kept constan-t.
This applies to a cer-taln chosen electrode morpho:Logy; ~ as well as the exponent n in the above equa-tion depend on the electrod0 morphology, For a gauze elec-30 trode, for example~ n = 3/8 and for a sputtered electroden = -1/2.
Wi-th a correc-t chc,ice of the electrode morphology and the dimensions of the tablet, the resistance value of the electrolrte ls small wlth respect to the overal,l 35 resistance~d~ay then be neglected. The measuring range within whlch rellable values can be obtainecl depends on the chosen combination of tempera-ture/oxygen partial pre~;sure of
During the measurement the temperature of the solid electrol~yte in prac-tice mus-t at least be 250C, A disadvantage of this known type of oxygen sensor is that a re~erence gas having an oxygen concentra-2~ tion which is kept accurately constant is essential.
I-t is -the obJect of the invention to provide a sensor which operates without using such a reference gas.
According to the invention, the sensor of -the above-described type using a solid electrolyte wl~h ion 30 conductivity which is provided on both sides with electrode coatings is characterized in that the solid electrolyte consists o~ stabilised ~i203 in the form of a tablet which co~prises elec-trode coatings and is surrounded entirely by P'HN 'IO.'l95 2 'l.10.'l982 the gas to ~e ana:lyzed and -tha-t the resis-tance ~et-ween the elec-trocl,e coatings ls measured as an oxygen partial pressure-dependent quanti-ty.
The ~i2O3 is stabilised ln known manner by the addltion or yttrlum oxlcle, an o~ide of an elemen-t from the lanthanlcle group havlng an atomic number between 62 and 7O incl-uding the -terminal values niobium oxide, tanta-lum oxide or tungsten oxide, As a resul-t of stabilisation the material obtains a face~centred cu'bic lattice and only in this s-tructure can it be used as a sensor.
The operation of the sensor according to the invention is based on the variation of the electrode resistance as a function of the oxygen partial pressure.
By means o~ a direct current vol-tage the resistance of the eLectrode/electrolyte combina-tion is measured. For this it holds that:
electrode to-tal Uelectrolyte ~-Rtotal is the quant;ity to 'be measured;
Relec-trolyte and also I~ are quantities which are incdependent of the oxygen par-tial pressure and a known function o~ the temperature~ With -the choice of a deflni-te temperature9 both are constants. In this case also the 25 measurement mus-t thus be carried out at a particular tempe-rature which is kept constan-t.
This applies to a cer-taln chosen electrode morpho:Logy; ~ as well as the exponent n in the above equa-tion depend on the electrod0 morphology, For a gauze elec-30 trode, for example~ n = 3/8 and for a sputtered electroden = -1/2.
Wi-th a correc-t chc,ice of the electrode morphology and the dimensions of the tablet, the resistance value of the electrolrte ls small wlth respect to the overal,l 35 resistance~d~ay then be neglected. The measuring range within whlch rellable values can be obtainecl depends on the chosen combination of tempera-ture/oxygen partial pre~;sure of
3~
PMN 'l0.l95 3 'l.'l0.1982 the ~sensor ancl of the natu.re o* the electroc'le~ and generally is in the tempera-ture range from 500 to 800C
and a range of oxygen partial pressures of 10 -105Pa (10 3 -I atmosphere). In this manner a small contact surface of the electrodes with -the solid e:lectrolyte shifts the range towards higher values of the oxygen partial pressure.
The special feature of the presen-t sys-tem is that the temperature range within wl~ch it can be used is much lower t~an in other systems, for example, ZrO2 stabili-sed by Y203, and is so low that ageing 'has an immeasurably small effect~ Moreover, the resistance as a function of the oxygen pressure shows a monotonous variati.on in contrast with other sys-tems in which a minimum occurs within -the 15 ~eaguring range.
The elec-trode coa-tings of -the sensor accordi.ng to the invention consists of noble metal~ for example Pd or Au, bu-t platinum is -to be preferred. An advantage :is also -that the sensor according -to the inven-tion is suitable for ~ miniaturisationO
As already no-ted above, in the sensor according to ths invention, as in other sys-tems, -the disadvantage exists of the necessity of -the -use of a thermostat. Thi.s can be avoided, howe-ver~ by meas-uring the electrolyte resis-25 tance with two alterna-ting current frequencies, a low value (less than 100 ~Iz) and a high value (10 K~Iz or higher3. The temperature can be determined by means of the impedance circle with which the real part and the imaginary part of -the impedance is descri'bed. At the high freq1lency the said 30 circle intersects -the axis and then gives -the res:is-tance of the electrolyte 7 at the low frequency the circle also in-tersects the axis and thus provides the value of the sum of electrolyte plus electrodeO The -value of the resistance at the high frequenc~ can 'be plotted on a calibration curve 35 as a function of the temperature. In this manner the tempera-ture can be read7 if desired by means of a reference curve stored in a microprocessor. In that case a thermocouple is : ', 3~1~$
PMN -10. 195 ~ 1 .10. 1982 not neeessary in the sensor but~ o~` course~ a grenera-tor o~ the al-terna-ting voltage si~na:l and possibly a micro-processor having a eircuit eoupled thereto are neeessary.
The clescription of' two cons-true-tions of` ~n oxygen sensor aecording to the invention is now gi~en by way of example.
~xample I
A sintered tablet o~ -the composition (Bi23)0 80~Er2 3)0.20 having a cliame-ter of 7 mm and a -thickness o~
1.5 mm was provided with a 0~7/Um thick platinum layer on both major surfaces by sputtering. For this construction the value ~ in the above ~ormula is n - -1/2.
At 700C the following values were measured:
R ( 100% 0 ) _ Z . 6 5~L
eleetrocle 2 " (1.~ / 2~= 22.3 ReleetrolYte 2-5 K = 2.7 + Ool;
and at 550C
eleetrode(100% ()2 - 62~
Relectrode(1~ G% 2) 420 Q
eleetrolytel30Q
K - 5g /+ 4 Fxample 2 A platinum gau~e having 200 meshes/em was sandwiehed between two tablets of the ~dme eomposi-tion as 30 the table-t used in ~xample lo For this eonstruetion a value of n = ~3/8 holds in the above formula.
At 700 C the following values were measured;
R (100% 0 ) = 73 Q
eleetrode 2 Relec-trode(1~% O2) = 3535~
Releetrolyte 5Q
K ~ 74 ~ 1;
~nd at 550 C the following values:
P~IN lO.195 5 I. lO. I982 electrocle (100% 2) = 1420 Q
ele c I;rode ( 1 . 60/o 2 ) = 54 5 Relectrol~rte 49O 5 = 1300 ~ 100 -
PMN 'l0.l95 3 'l.'l0.1982 the ~sensor ancl of the natu.re o* the electroc'le~ and generally is in the tempera-ture range from 500 to 800C
and a range of oxygen partial pressures of 10 -105Pa (10 3 -I atmosphere). In this manner a small contact surface of the electrodes with -the solid e:lectrolyte shifts the range towards higher values of the oxygen partial pressure.
The special feature of the presen-t sys-tem is that the temperature range within wl~ch it can be used is much lower t~an in other systems, for example, ZrO2 stabili-sed by Y203, and is so low that ageing 'has an immeasurably small effect~ Moreover, the resistance as a function of the oxygen pressure shows a monotonous variati.on in contrast with other sys-tems in which a minimum occurs within -the 15 ~eaguring range.
The elec-trode coa-tings of -the sensor accordi.ng to the invention consists of noble metal~ for example Pd or Au, bu-t platinum is -to be preferred. An advantage :is also -that the sensor according -to the inven-tion is suitable for ~ miniaturisationO
As already no-ted above, in the sensor according to ths invention, as in other sys-tems, -the disadvantage exists of the necessity of -the -use of a thermostat. Thi.s can be avoided, howe-ver~ by meas-uring the electrolyte resis-25 tance with two alterna-ting current frequencies, a low value (less than 100 ~Iz) and a high value (10 K~Iz or higher3. The temperature can be determined by means of the impedance circle with which the real part and the imaginary part of -the impedance is descri'bed. At the high freq1lency the said 30 circle intersects -the axis and then gives -the res:is-tance of the electrolyte 7 at the low frequency the circle also in-tersects the axis and thus provides the value of the sum of electrolyte plus electrodeO The -value of the resistance at the high frequenc~ can 'be plotted on a calibration curve 35 as a function of the temperature. In this manner the tempera-ture can be read7 if desired by means of a reference curve stored in a microprocessor. In that case a thermocouple is : ', 3~1~$
PMN -10. 195 ~ 1 .10. 1982 not neeessary in the sensor but~ o~` course~ a grenera-tor o~ the al-terna-ting voltage si~na:l and possibly a micro-processor having a eircuit eoupled thereto are neeessary.
The clescription of' two cons-true-tions of` ~n oxygen sensor aecording to the invention is now gi~en by way of example.
~xample I
A sintered tablet o~ -the composition (Bi23)0 80~Er2 3)0.20 having a cliame-ter of 7 mm and a -thickness o~
1.5 mm was provided with a 0~7/Um thick platinum layer on both major surfaces by sputtering. For this construction the value ~ in the above ~ormula is n - -1/2.
At 700C the following values were measured:
R ( 100% 0 ) _ Z . 6 5~L
eleetrocle 2 " (1.~ / 2~= 22.3 ReleetrolYte 2-5 K = 2.7 + Ool;
and at 550C
eleetrode(100% ()2 - 62~
Relectrode(1~ G% 2) 420 Q
eleetrolytel30Q
K - 5g /+ 4 Fxample 2 A platinum gau~e having 200 meshes/em was sandwiehed between two tablets of the ~dme eomposi-tion as 30 the table-t used in ~xample lo For this eonstruetion a value of n = ~3/8 holds in the above formula.
At 700 C the following values were measured;
R (100% 0 ) = 73 Q
eleetrode 2 Relec-trode(1~% O2) = 3535~
Releetrolyte 5Q
K ~ 74 ~ 1;
~nd at 550 C the following values:
P~IN lO.195 5 I. lO. I982 electrocle (100% 2) = 1420 Q
ele c I;rode ( 1 . 60/o 2 ) = 54 5 Relectrol~rte 49O 5 = 1300 ~ 100 -
Claims (4)
PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A sensor for determining the oxygen content in a gas by using a solid electrolyte which shows ion conductivity and which has electrode coatings on both sides, characterized in that the solid electrolyte consists of stabilised Bi2O3 in the form of a tablet which is provided with electrode coatings and is surrounded by the gas to be analysed and that the resistance between the electrode coatings is measured as an oxygen partial pres-sure-dependent quantity.
2. A sensor as claimed in Claim 1, characterized in that the electrode coatings consist of platinum.
3. A measuring device comprising a sensor as claim-ed in Claim 1 or 2.
4. A measuring device comprising a sensor as claimed in Claim 1 or 2 and means for measuring the resistance of the solid electrolyte at a frequency of at least 10 KHz and determination of the temperature of the sensor from the resulting resistance value, if desired by means of a reference curve stored in a microprocessor.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NL8105116A NL8105116A (en) | 1981-11-12 | 1981-11-12 | SENSOR FOR DETERMINING THE OXYGEN CONTENT IN A FLUIDUM. |
| NL8105116 | 1981-11-12 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1198345A true CA1198345A (en) | 1985-12-24 |
Family
ID=19838359
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000415207A Expired CA1198345A (en) | 1981-11-12 | 1982-11-09 | Sensor for determining the oxygen content in a gas |
Country Status (6)
| Country | Link |
|---|---|
| US (1) | US4770761A (en) |
| EP (1) | EP0079652B1 (en) |
| JP (1) | JPS5888645A (en) |
| CA (1) | CA1198345A (en) |
| DE (1) | DE3277080D1 (en) |
| NL (1) | NL8105116A (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5006494A (en) * | 1989-04-24 | 1991-04-09 | Gas Research Institute | Stabilized bismuth oxide |
| US5183801A (en) * | 1989-04-24 | 1993-02-02 | Gas Research Institute | Stabilized bismuth oxide |
| US5332524A (en) * | 1992-04-20 | 1994-07-26 | Valkyrie Scientific Proprietary, L.C. | Methods for dissolving water soluble polymers and compositions using same |
| JP2927159B2 (en) * | 1993-10-01 | 1999-07-28 | 富士ゼロックス株式会社 | Electrophotographic charging roll |
| DE19617297A1 (en) * | 1996-04-30 | 1997-11-13 | Brand Gerhart Rosemarie | Simultaneous detection of oxidizable and reducible gases with metal oxide sensors using impedance spectroscopy |
| US20060231422A1 (en) * | 2005-04-14 | 2006-10-19 | Honeywell International Inc. | Switched gas sensor |
Family Cites Families (22)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3691023A (en) * | 1970-12-15 | 1972-09-12 | Westinghouse Electric Corp | Method for polarographic measurement of oxygen partial pressure |
| NL7411044A (en) * | 1974-08-19 | 1976-02-23 | Philips Nv | MEASURING CELL FOR DETERMINING OXYGEN CONCENTRATIONS IN A GAS MIXTURE. |
| JPS51138494A (en) * | 1975-05-26 | 1976-11-30 | Nissan Motor Co Ltd | Oxygen sensor |
| US4244918A (en) * | 1975-12-23 | 1981-01-13 | Nippon Soken, Inc. | Gas component detection apparatus |
| US4071817A (en) * | 1976-03-08 | 1978-01-31 | Suntech, Inc. | High temperature electrochemical cell tester |
| DE2648373C2 (en) * | 1976-10-26 | 1986-01-02 | Robert Bosch Gmbh, 7000 Stuttgart | Semiconductors for sensors for determining the content of oxygen and / or oxidizable components in exhaust gases |
| JPS5395097A (en) * | 1977-01-31 | 1978-08-19 | Toshiba Corp | Gas-sensitive element |
| DE2711880C2 (en) * | 1977-03-18 | 1985-01-17 | Robert Bosch Gmbh, 7000 Stuttgart | Polarographic probe for measuring oxygen concentration and process for its manufacture |
| JPS609978B2 (en) * | 1977-08-22 | 1985-03-14 | 東レ株式会社 | Oxygen ion conductive solid electrolyte |
| JPS608459B2 (en) * | 1977-09-30 | 1985-03-02 | 松下電器産業株式会社 | gas detection element |
| JPS584985B2 (en) * | 1978-05-10 | 1983-01-28 | 株式会社日立製作所 | gas detection element |
| JPS584986B2 (en) * | 1978-06-16 | 1983-01-28 | 日産自動車株式会社 | Oxygen concentration measuring device |
| JPS5518922A (en) * | 1978-07-26 | 1980-02-09 | Fuji Electric Co Ltd | Oxygen sensor |
| JPS5562349A (en) * | 1978-11-02 | 1980-05-10 | Nissan Motor Co Ltd | Measuring method for air fuel ratio |
| DE2908916C2 (en) * | 1979-03-07 | 1986-09-04 | Robert Bosch Gmbh, 7000 Stuttgart | Resistance sensor for detecting the oxygen content in gases, in particular in exhaust gases from internal combustion engines, and a method for producing the same |
| JPS55155859A (en) * | 1979-05-25 | 1980-12-04 | Towa Kogyo Kk | Method of waterproofing |
| DE2922131A1 (en) * | 1979-05-31 | 1980-12-18 | Bosch Gmbh Robert | POLAROGRAPHIC PROBE FOR DETERMINING THE OXYGEN CONTENT IN GAS, ESPECIALLY IN EXHAUST GAS FROM COMBUSTION ENGINES |
| JPS55166039A (en) * | 1979-06-12 | 1980-12-24 | Nissan Motor Co Ltd | Air fuel ratio detector |
| JPS6029065B2 (en) * | 1979-07-28 | 1985-07-08 | 日産自動車株式会社 | Air-fuel ratio control signal generator |
| US4233033A (en) * | 1979-09-19 | 1980-11-11 | Bendix Autolite Corporation | Method and apparatus for measuring the O2 content of a gas |
| JPS5692447A (en) * | 1979-12-26 | 1981-07-27 | Nissan Motor Co Ltd | Production of film-structure oxygen sensor element |
| JPS57192849A (en) * | 1981-05-25 | 1982-11-27 | Toyota Central Res & Dev Lab Inc | Detecting device for limit current system oxygen concentration performing temperature compensation of measuring output |
-
1981
- 1981-11-12 NL NL8105116A patent/NL8105116A/en not_active Application Discontinuation
-
1982
- 1982-11-09 JP JP57195431A patent/JPS5888645A/en active Granted
- 1982-11-09 CA CA000415207A patent/CA1198345A/en not_active Expired
- 1982-11-10 DE DE8282201422T patent/DE3277080D1/en not_active Expired
- 1982-11-10 EP EP82201422A patent/EP0079652B1/en not_active Expired
-
1984
- 1984-04-02 US US06/595,784 patent/US4770761A/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| DE3277080D1 (en) | 1987-10-01 |
| JPS5888645A (en) | 1983-05-26 |
| EP0079652A1 (en) | 1983-05-25 |
| US4770761A (en) | 1988-09-13 |
| NL8105116A (en) | 1983-06-01 |
| EP0079652B1 (en) | 1987-08-26 |
| JPH0423212B2 (en) | 1992-04-21 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |