GB2186091A - Semiconductor gas sensor - Google Patents
Semiconductor gas sensor Download PDFInfo
- Publication number
- GB2186091A GB2186091A GB08702373A GB8702373A GB2186091A GB 2186091 A GB2186091 A GB 2186091A GB 08702373 A GB08702373 A GB 08702373A GB 8702373 A GB8702373 A GB 8702373A GB 2186091 A GB2186091 A GB 2186091A
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- United Kingdom
- Prior art keywords
- sensor device
- semiconductor material
- electrical sensor
- pellet
- semiconductor
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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
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B18/00—Layered products essentially comprising ceramics, e.g. refractory products
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
- C04B35/495—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on vanadium, niobium, tantalum, molybdenum or tungsten oxides or solid solutions thereof with other oxides, e.g. vanadates, niobates, tantalates, molybdates or tungstates
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
- C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
- C04B2235/30—Constituents and secondary phases not being of a fibrous nature
- C04B2235/32—Metal oxides, mixed metal oxides, or oxide-forming salts thereof, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
- C04B2235/3205—Alkaline earth oxides or oxide forming salts thereof, e.g. beryllium oxide
- C04B2235/3213—Strontium oxides or oxide-forming salts thereof
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
- C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
- C04B2235/30—Constituents and secondary phases not being of a fibrous nature
- C04B2235/32—Metal oxides, mixed metal oxides, or oxide-forming salts thereof, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
- C04B2235/3205—Alkaline earth oxides or oxide forming salts thereof, e.g. beryllium oxide
- C04B2235/3215—Barium oxides or oxide-forming salts thereof
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
- C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
- C04B2235/30—Constituents and secondary phases not being of a fibrous nature
- C04B2235/32—Metal oxides, mixed metal oxides, or oxide-forming salts thereof, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
- C04B2235/3231—Refractory metal oxides, their mixed metal oxides, or oxide-forming salts thereof
- C04B2235/3251—Niobium oxides, niobates, tantalum oxides, tantalates, or oxide-forming salts thereof
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2237/00—Aspects relating to ceramic laminates or to joining of ceramic articles with other articles by heating
- C04B2237/30—Composition of layers of ceramic laminates or of ceramic or metallic articles to be joined by heating, e.g. Si substrates
- C04B2237/32—Ceramic
- C04B2237/34—Oxidic
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2237/00—Aspects relating to ceramic laminates or to joining of ceramic articles with other articles by heating
- C04B2237/30—Composition of layers of ceramic laminates or of ceramic or metallic articles to be joined by heating, e.g. Si substrates
- C04B2237/32—Ceramic
- C04B2237/34—Oxidic
- C04B2237/345—Refractory metal oxides
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2237/00—Aspects relating to ceramic laminates or to joining of ceramic articles with other articles by heating
- C04B2237/30—Composition of layers of ceramic laminates or of ceramic or metallic articles to be joined by heating, e.g. Si substrates
- C04B2237/32—Ceramic
- C04B2237/34—Oxidic
- C04B2237/345—Refractory metal oxides
- C04B2237/346—Titania or titanates
Abstract
An electrical sensor device (1) suitable for use in a gas or gaseous mixture includes a sensing portion having, in communication, a first semiconductor material (2) and a second semiconductor material (3). The semiconductor materials may be metal oxides in contact with each other. Electrodes (4), (5) connected to a respective semiconductor material are connected to high impedance voltmeter (8) for measuring the voltage produced by device (1) when contacted by a gas such as H2, CO, C2H4. The device (1) is formed by introducing consecutively powders of first and second semiconductor materials into a die and pressing to give a porous pellet. Electrodes (4) (5) are then formed by sputtering or painting. <IMAGE>
Description
SPECIFICATION
Sensor
The present invention relates to sensors and more particularly to an electical sensor device which is suitable for use in gases or gaseous mixtures.
According to one aspect of the present invention there is provided an electrical sensor device which includes a sensing portion having a first semiconductor material and a second semiconductor material, said first semiconductor material and said second semiconductor material being in communication.
The sensor device may include a means for measuring a voltage produced by the sensing portion (e.g. a high impedance voltmeter may be used).
Preferably the first and second semiconductor materials are in communication by being in mutual contact.
Examples of semiconductor materials which may be used in a sensor device in accordance with the present invention are semiconductor oxides such as BaO,2ssro 7sNb2o6v BaO,7sSrO2sNb2o6 BaSnO3, BaTiO3 and K4Nb6017.
By way of example a sensor device of the present invention may be used to detect in air, gases such as hydrogen, carbon monoxide and C2H4.
It is preferred that the sensing portion is porous in order to provide extended surface area for contact with a gas or gaseous mixture.
An electrical sensor device in accordance with one embodiment of the present invention may comprise a sensing portion including a pellet having a first semiconductor material and a second semiconductor material in contact.
It will be appreciated that, in accordance with the immediately preceding embodiment of the present invention, the pellet has a composite structure.
Thus, for example, the pellet may be a pellet having two regions, one region being a first semiconductor oxide and the second region being a second semiconductor oxide.
The two regions may comprise two layers of the composite pellet.
The means for measuring the voltage produced may be, for example, a high impedance voltmeter (e.g. a digital voltmeter (DVM)).
In one embodiment of the present invention a pellet for use in accordance with the present invention may be prepared by pressing a first semiconductor material in powder form and a second semiconductor material in powder form to give a porous pellet.
The porous pellet may be provided with electrodes (e.g. of Au or Pt), for example, by painting or sputtering. The electrodes may be provided one on each of the semiconductor materials. Electrodes may be of like material (e.g. both electrodes may be of a Au or both of Pt). The electrodes allow electrical connection to a voltage measuring means via suitable conductors (e.g. Cu wire). It will be appreciated that the response of the electrical sensor device to gases and gaseous mixtures may be monitored by measuring the potential between the electrodes.
In another embodiment of the present invention a pellet for use in accordance with the present invention may be prepared by pressing a first semiconductor material in powder form and a second semiconductor material in powder form such that a porous pellet is formed having a region comprising a first semiconductor material and a region comprising a second semiconductor material.
Thus, for example, in accordance with the immediately preceding embodiment of the invention a first semiconductor material in powder form may be introduced into a die and a second semiconductor material in powdered form may be added to the die to give two regions of powdered material in the die.
Pressing may be carried out to give a porous pellet having a region comprising a first semiconductor material and a region comprising a second semiconductor material.
It will be appreciated that since the measured voltage is developed by the sensing portion the requirement of providing an external electrical supply as is necessary in the case of a sensor working on, for example, resisitivity changes, is substantially avoided (i.e. a device in accordance with the present invention may be substantially "self-powered").
It will be appreciated that in operation a gaseous mixture may be passed over a sensor device in accordance with the present invention, a voltage is developed due to a potential difference between the surfaces of the two semiconductor materials and the voltage is measured.
The magnitude of the voltage is related to the concentration in the gaseous mixture of gas which gives a potential difference between the two semiconductor materials. Thus it is possible, for example, to detect (e.g. H2,
CO, and C2H4) in air.
Sensor devices in accordance with the present invention are believed to be less prone to moisture "poisoning" than high resistance modulating devices.
In accordance with another aspect of the present invention there is provided a method of sensing a gas which comprises contacting the gas with an electrical sensor device which includes a sensing portion having a first semiconductor material and a second semiconductor material, said first semiconductor material and said second semiconductor material being in communication, and measuring the voltage produced.
By way of example, an electrical sensor device having a sensing portion including a composite pellet comprising a layer of BaO2sSrO7sNb2o6 in contact with a layer of Ba0.75Sra25Nb2O6 and provided with gold electrodes gave a response (at about 300"C) to
1% hydrogen in air, 1% ethane in air and reduced oxygen partial pressure.
Electrical sensor devices, by way of further example, having composite pellets of BaSnO3 in contact with BaTiO3 and K4Nb6O17 in contact with BaSnO3 have also shown responses to gases.
The invention will now be further described, by way of example only, with reference to the accompanying drawings and with reference to
Examples 1 to 3.
In the Drawings:
Figure 1 is a diagrammatic representation of an electrical sensor device in accordance with the invention;
Figure 2 shows the voltage response of an electrical sensor device in accordance with the present invention (having a sensing portion including a composite pellet of Ba0.25Sr075Nb2O6/ BaO 7sSrO,2sNb206 having gold electrodes) to gases as a function of temperature (with T rising);
Figure 3 shows the voltage response of an electrical sensor device in accordance with the present invention (having a sensing portion including a composite pellet of BaO 25SrO 75Nb2O6/
BaO 7sSrO,2sNb206 having gold electrodes) to gases as a function of temperature (with T falling);;
Figure 4 shows the voltage response of an electrical sensor device in accordance with the present invention (having a sensing portion including a composite pellet of BaSnO3/BaTiO3 having gold electrodes) to gases as a function of temperature (with T rising);
Figure 5 shows the voltage response of an electrical sensor device in accordance with the present invention (having a sensing portion including a composite pellet of BaSnO3/BaTiO3 having gold electrodes) to gases as a function of temperature (with T falling); and
Figure 6 shows the voltage response of an electrical sensor device in accordance with the present invention (having a sensing portion including a composite pellet of K4Nb6017/BaSnO3 having gold electrodes) to air, 90% N2/10% 02, various reducing gases in air and to 100% CO2.
Referring now to Fig. 1, there is shown an electrical sensor device comprising a cylindrical pellet 1 provided with a region 2 comprising a first semiconductor material and a region 3 comprising a second semiconductor material.
Electrodes 4 and 5 are provided and are connected via conductors 6 and 7 respectively to a voltage measuring means 8.
In operation a gaseous mixture containing a gas to be detected is passed over pellet 1, voltage is developed between the region 2 and region 3 and the voltage is measured by voltage measuring means 8.
Example 1
A sensor device of the form shown in Fig.
1 of the accompanying drawings was formed by pressing powders as hereinbefore disclosed and used to detect various reducing gases in air and to detect reduced oxygen partial pressure.
The sensor device had a composite pellet comprising a layer of BaO2sSrO7sNb2o6 in contact with a layer of BaO7sSrO2sNb2o6 each layer being provided respectively (at opposite ends of the pellet) with a gold electrode (by painting).
The gold electrodes were connected to a voltage measuring device (DVM) via copper wires.
The sensor device was placed in an enclosure and a sequence of different gases was passed over the device at a number of temperatures.
Thus, 1% hydrogen in air was passed over the sensor device, followed by 1% ethene in air and then 100% CO2 (equivalent to a reduced oxygen partial pressure of 10-6 atmospheres). Each of the test gases was passed over the sensor device for 10 minutes followed by 10 minutes air purge prior to passage of the next gas.
The results are shown in Fig. 2 (temperature rising) and Fig. 3 (temperature falling).
It will be seen that 1% hydrogen in air, 1% ethene in air and the CO2 gave largest responses in the the region of 300"C.
At higher temperatures the responses to hydrogen and to ethene first decrease and then change sign.
It will be seen that for the particular sensor of this Example the response to 100% CO2 is small.
The responses obtained during temperature rising (Fig. 2) were broadly reproduced during temperature falling (Fig. 3).
Example 2
A sensor device of the form shown in Fig.
1 of the accompanying drawings was formed by pressing and used to detect various reducing gases in air and to detect reduced oxygen partial pressure.
The sensor device had a composite pellet comprising a layer of BaSnO3 in contact with a layer of BaTiO3 each layer being provided respectively (at opposite ends of the pellet) with a gold electrode (by painting).
The gold electrodes were connected to a voltage measuring device (DVM) via copper wires.
The sensor device was placed in an enclosure and a sequence of different gases was passed over the device at a number of temperatures.
Thus, 1% hydrogen in air was passed over the sensor device, followed by 1% ethene in air and then 100% CO2 equivalent to a reduced oxygen partial pressure of 10-6 atmospheres). Each of the test gases was passed over the sensor device for 10 minutes followed by 10 minutes air purge prior to passage of the next gas).
Some difference may be seen when comparing the temperature rising responses (Fig.
4) and the temperature falling responses (Fig.
5). It is thought that this may be due to the removal of water at higher temperatures or to a change in stoichiometry (at least at the surface) of one of the semiconductor materials arising from the thermal excursion. During the temperature rising sequence the largest response to 1% hydrogen in air was an increase of positive potential of 50 to 100 mV which was largest at about 400 C.
In the same temperature region the responses to 1% ethene in air and 100% CO2 are also increases in positive potential.
At lower temperature the responses to all three gases gave negative moves in potential.
Under temperature falling conditions, over most of the temperature ranges studied, the response to the introduction of the three gases were negative-going potential shifts which were largest (over 100 mV) for 1% H2 in air at around 300 C.
Example 3
A sensor device of the form shown in Fig.
1 of the accompanying drawings was formed by pressing powders as herein before disclosed and used to detect various gases and to detect reduced oxygen partial pressure.
The sensor device had a composite pellet comprising a layer of K4Nb60,7 in contact with a layer of BaSnO3 each layer being provided respectively (at opposite ends of the pellet) with a gold electrode (by painting).
The gold electrodes were connected to a voltage measuring means (DVM) via copper wires.
The sensor device was placed in an enclosure and a sequence of gases was passed over the device while the temperature was held at about 500"C.
Thus, air was passed over the sensor device, followed by 100% carbon dioxide (equivalent to a reduced oxygen partial pressure of 10--6 atmospheres), then a mixture of 10% oxygen 90% nitrogen, then air containing 1% C2H4, then a mixture of 10% oxygen 90% nitrogen, then 1% CH4 in air, then a mixture of 10% oxygen 90% nitrogen, then 1% CO in air, then a mixture of 10% oxygen 90% nitrogen, then air containing 1% hydrogen and then a mixture of 10% O2 and 90% nitrogen.
The results are shown in Fig. 6.
The arrows in Fig. 6 indicate the points in time at which a particular indicated gas or gaseous mixture was introduced to the sensor device.
Most of the reducing gases gave rise to small negative going potential shifts, but the response to methane was in the opposite sense.
The largest response (150 mV) arose from the 100% CO2 contact and is thought to represent a reduced oxygen partial pressure response.
Claims (24)
1. An electrical sensor device which includes a sensing portion having a first semiconductor material and a second semiconductor material, said first semiconductor material and said second semiconductor material being in communication.
2. An electrical sensor device as claimed in
Claim 1 wherein the first semiconductor material is a semiconductor oxide.
3. An electrical sensor device as claimed in
Claim 2 wherein the semiconductor oxide is BaO 25SrO,75Nb206, BaO75SrO25Nb206, BaSnO3, BaTiO3 or K4Nb60l7
4. An electrical sensor device as claimed in
Claim 1 wherein the second semiconductor material is a semiconductor oxide.
5. An electrical sensor device as claimed in
Claim 4 wherein the semiconductor oxide is BaO 25SrO 75Nb2 6, BaO75SrO25Nb206, BaSnO3, BaTiO3 or K4Nb6017.
6. An electrical sensor device as claimed in any one of the preceding Claims wherein the sensing portion is porous.
7. An electrical sensor device as claimed is any one of the preceding Claims wherein the first and second semiconductor materials are in communication by being in mutual contact.
8. An electrical sensor device as claimed in any one of the preceding Claims wherein the sensing portion includes a pellet having a first semiconductor material and a second semico- ductor material in contact.
9. An electrical sensor device as claimed in
Claim 8 wherein the sensing portion comprises a pellet having two regions, one region being a first semiconductor oxide and the second region being a second semiconductor oxide.
10. An electrical sensor device as claimed in Claim 1 and including a means for measuring a voltage produced by the sensing portion.
11. An electrical sensor device as claimed in Claim 10 wherein the means for measuring a voltage comprises a high impedance voltmeter.
12. An electrical sensor device as claimed in any one of the preceding Claims having a sensing portion including a composite pellet comprising a layer of BaO25SrO75Nb206 in contact with a layer of BaO75SrO.25Nb206.
13. An electrical sensor device as claimed in any one of Claims 1 to 11 having a sensing portion including a composite pellet of BaSnO3 in contact with BaTiO3.
14. An electrical sensor as claimed in any one of Claims 1 to 11 having a sensing portion including a composite pellet of K4Nb60,7 in contact with BaSnO3.
15. A process for the preparation of a pellet for use in an electrical sensor device wherein a first semiconductor material in powder form and a seocnd semiconductor material in powder form are pressed to give a porous pellet.
16. A process as claimed in Claim 15 wherein the porous pellet is provided with electrodes by sputtering or painting.
17. A process for the preparation of a pellet for use in an electrical sensor device wherein said pellet is prepared by pressing a first semiconductor material in powder form and a second semiconductor material in powder form such that a porous pellet is formed having a region comprising a first semiconductor material and a region comprising a second semiconductor material.
18. A process as claimed in Claim 17 wherein a first semiconductor material in powder form is introduced into a die and a second semiconductor material in powdered form is added to the die to give two regions of powdered material in the die and pressing is carried out to give a porous pellet.
19. A method of sensing a gas which comprises contacting the gas with an electrical sensor device which includes a sensing portion having a first semiconductor material and a second semiconductor material, said first semiconductor material and said second semiconductor material being in communication, and measuring the voltage produced.
20. A method as claimed in Claim 19 wherein a gas is detected in air and said gas in hydrogen, carbon monoxide or C2H4.
21. An electrical sensor device substantially as herein before described with reference to Fig. 1 of the accompanying drawings.
22. An electrical sensor device substantially as hereinbefore described with reference to any one of the Examples 1, 2 or 3.
23. A process for preparing an electrical sensor device substantially as hereinbefore described with reference to any one of the
Examples 1, 2 or 3.
24. A process of sensing a gas substantially as hereinbefore described with reference to any one of the Examples 1, 2 or 3.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB868602544A GB8602544D0 (en) | 1986-02-03 | 1986-02-03 | Sensor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB8702373D0 GB8702373D0 (en) | 1987-03-11 |
| GB2186091A true GB2186091A (en) | 1987-08-05 |
Family
ID=10592405
Family Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB868602544A Pending GB8602544D0 (en) | 1986-02-03 | 1986-02-03 | Sensor |
| GB08702373A Withdrawn GB2186091A (en) | 1986-02-03 | 1987-02-03 | Semiconductor gas sensor |
Family Applications Before (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB868602544A Pending GB8602544D0 (en) | 1986-02-03 | 1986-02-03 | Sensor |
Country Status (1)
| Country | Link |
|---|---|
| GB (2) | GB8602544D0 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1996000895A1 (en) * | 1994-06-29 | 1996-01-11 | Max-Planck-Gesellschaft zur Förderung der Wissenschaften e.V., Berlin | Potentiometric co2 sensor with a titanate and stannate-based open reference electrode |
| EP0701123A1 (en) | 1994-09-10 | 1996-03-13 | United Kingdom Atomic Energy Authority | Formaldehyde vapour detector |
| WO1997047962A1 (en) * | 1996-06-11 | 1997-12-18 | Robert Bosch Gmbh | Sensor for determining the concentration of oxidisable elements in a gas compound |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1203126A (en) * | 1968-10-31 | 1970-08-26 | James Edgar Meinhard | Electronic olfactory detector |
| GB1474345A (en) * | 1974-08-19 | 1977-05-25 | Philips Electronic Associated | Device for determining oxygen concentrations in a gas mixture |
| GB1533657A (en) * | 1974-12-17 | 1978-11-29 | Mullard Ltd | Electronic solid state devices |
| GB1543268A (en) * | 1975-08-19 | 1979-03-28 | Nohmi Bosai Kogyo Co Ltd | Gas detecting element |
| EP0024679A1 (en) * | 1979-08-22 | 1981-03-11 | Siemens Aktiengesellschaft | Selective gas sensor with great sensitivity and stability for determining and measuring the degree of air pollution on the basis of metal oxide semiconductors |
| US4481499A (en) * | 1982-05-07 | 1984-11-06 | Hitachi, Ltd. | Gas detector |
| GB2149122A (en) * | 1983-10-31 | 1985-06-05 | Atomic Energy Authority Uk | Improvements in or relating to sensors |
| GB2149121A (en) * | 1983-10-31 | 1985-06-05 | Atomic Energy Authority Uk | Improvements in or relating to sensors |
-
1986
- 1986-02-03 GB GB868602544A patent/GB8602544D0/en active Pending
-
1987
- 1987-02-03 GB GB08702373A patent/GB2186091A/en not_active Withdrawn
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1203126A (en) * | 1968-10-31 | 1970-08-26 | James Edgar Meinhard | Electronic olfactory detector |
| GB1474345A (en) * | 1974-08-19 | 1977-05-25 | Philips Electronic Associated | Device for determining oxygen concentrations in a gas mixture |
| GB1533657A (en) * | 1974-12-17 | 1978-11-29 | Mullard Ltd | Electronic solid state devices |
| GB1543268A (en) * | 1975-08-19 | 1979-03-28 | Nohmi Bosai Kogyo Co Ltd | Gas detecting element |
| EP0024679A1 (en) * | 1979-08-22 | 1981-03-11 | Siemens Aktiengesellschaft | Selective gas sensor with great sensitivity and stability for determining and measuring the degree of air pollution on the basis of metal oxide semiconductors |
| US4481499A (en) * | 1982-05-07 | 1984-11-06 | Hitachi, Ltd. | Gas detector |
| GB2149122A (en) * | 1983-10-31 | 1985-06-05 | Atomic Energy Authority Uk | Improvements in or relating to sensors |
| GB2149121A (en) * | 1983-10-31 | 1985-06-05 | Atomic Energy Authority Uk | Improvements in or relating to sensors |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1996000895A1 (en) * | 1994-06-29 | 1996-01-11 | Max-Planck-Gesellschaft zur Förderung der Wissenschaften e.V., Berlin | Potentiometric co2 sensor with a titanate and stannate-based open reference electrode |
| US5910239A (en) * | 1994-06-29 | 1999-06-08 | Max-Plank-Gesellschaft Zur | Potentiometric CO2 sensor having an open titanate- or stannate-based reference electrode |
| EP0701123A1 (en) | 1994-09-10 | 1996-03-13 | United Kingdom Atomic Energy Authority | Formaldehyde vapour detector |
| WO1997047962A1 (en) * | 1996-06-11 | 1997-12-18 | Robert Bosch Gmbh | Sensor for determining the concentration of oxidisable elements in a gas compound |
Also Published As
| Publication number | Publication date |
|---|---|
| GB8702373D0 (en) | 1987-03-11 |
| GB8602544D0 (en) | 1986-03-12 |
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