GB2334105A - Catalytic combustible gas sensor - Google Patents
Catalytic combustible gas sensor Download PDFInfo
- Publication number
- GB2334105A GB2334105A GB9901242A GB9901242A GB2334105A GB 2334105 A GB2334105 A GB 2334105A GB 9901242 A GB9901242 A GB 9901242A GB 9901242 A GB9901242 A GB 9901242A GB 2334105 A GB2334105 A GB 2334105A
- Authority
- GB
- United Kingdom
- Prior art keywords
- gas sensor
- woven fabric
- combustible gas
- measuring element
- sensor according
- 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.)
- Withdrawn
Links
- 230000003197 catalytic effect Effects 0.000 title claims abstract description 38
- 239000003054 catalyst Substances 0.000 claims abstract description 34
- 239000004745 nonwoven fabric Substances 0.000 claims abstract description 21
- 239000002759 woven fabric Substances 0.000 claims abstract description 20
- 239000000919 ceramic Substances 0.000 claims description 25
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 claims description 20
- 239000000758 substrate Substances 0.000 claims description 15
- 229910052697 platinum Inorganic materials 0.000 claims description 9
- 239000012212 insulator Substances 0.000 claims description 7
- 239000003365 glass fiber Substances 0.000 claims description 5
- 239000000853 adhesive Substances 0.000 claims description 4
- 230000001070 adhesive effect Effects 0.000 claims description 4
- 239000011259 mixed solution Substances 0.000 claims description 4
- 239000002253 acid Substances 0.000 claims description 3
- PIBWKRNGBLPSSY-UHFFFAOYSA-L palladium(II) chloride Chemical compound Cl[Pd]Cl PIBWKRNGBLPSSY-UHFFFAOYSA-L 0.000 claims description 3
- 238000010304 firing Methods 0.000 claims description 2
- 239000000203 mixture Substances 0.000 claims description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims 2
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 claims 2
- 229910052763 palladium Inorganic materials 0.000 claims 1
- 239000010970 precious metal Substances 0.000 claims 1
- 229910052703 rhodium Inorganic materials 0.000 claims 1
- 239000010948 rhodium Substances 0.000 claims 1
- MHOVAHRLVXNVSD-UHFFFAOYSA-N rhodium atom Chemical compound [Rh] MHOVAHRLVXNVSD-UHFFFAOYSA-N 0.000 claims 1
- 238000009413 insulation Methods 0.000 description 6
- 239000010410 layer Substances 0.000 description 5
- 239000010408 film Substances 0.000 description 3
- 239000011521 glass Substances 0.000 description 3
- 238000005259 measurement Methods 0.000 description 3
- 238000010276 construction Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 230000002035 prolonged effect Effects 0.000 description 2
- 239000011241 protective layer Substances 0.000 description 2
- 230000035945 sensitivity Effects 0.000 description 2
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000020169 heat generation Effects 0.000 description 1
- 239000011810 insulating material Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 150000003057 platinum Chemical class 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 230000000644 propagated effect Effects 0.000 description 1
- 238000002791 soaking Methods 0.000 description 1
- 125000006850 spacer group Chemical group 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 239000010409 thin film Substances 0.000 description 1
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
- G01N27/14—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance of an electrically-heated body in dependence upon change of temperature
- G01N27/16—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance of an electrically-heated body in dependence upon change of temperature caused by burning or catalytic oxidation of surrounding material to be tested, e.g. of gas
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)
Abstract
The invention provides a catalytic combustible gas sensor having a measuring element and a reference element, wherein a catalyst supported on a woven or non-woven fabric is stuck to the measuring element.
Description
CATALYTIC COMBUSTIBLE GAS SENSOR
The present invention relates to a catalytic combustible gas sensor and in particular, relates to catalytic combustible gas sensors whose sensor accuracy is improved, cost is reduced, and service life is prolonged.
BACKGROUND OF THE INVENTION
Commercially-available catalytic combustible gas sensors typically have the following construction: A thin platinum wire is worked into a filament, the filament is coated with alumina or the like, and an oxidising catalyst is stuck to the surface of that covering layer. The combustible gas detector using this type of element is used for measurement by constructing a Wheatstone bridge with two arms of a pair of the above thin platinum wire filaments and two arms of resistors having nearly equal resistance values.
One of the pair of thin platinum wire filaments is used as a combustible gas detecting element and the other is used as the reference element. The reference element is made without oxidising catalyst so that the temperature of the reference element does not rise when it comes in contact with a combustible gas. Alternatively. if the reference element has an oxidising catalyst, the reference element is made with an enclosed construction so that a combustible gas does not reach the oxidising catalyst.
The temperature of the elements is maintained within the range of 200 to 500"C by passing currents through the pair of filaments. When there is no combustible gas, the bridge resistance values are adjusted so that the bridge remains balanced
The resistance value of the measuring element increases when the temperature of this element rises due to the fact that a combustible gas burns when the gas comes in contact with the measuring element. Then the balance of the bridge is broken and a potential difference arises.
However, detectors of such a configuration make it difficult to obtain uniformity in the measuring element and the reference element.
A detector that solves the above problem is described below The detector has a platinum film formed on a heat-resistive insulator substrate using the thin film method or the thick film method, a heat-resistive insulation layer is formed on the substrate having the platinum film, and a catalytic material is stuck to the insulation layer The use of such an element allows multiple measuring elements and reference elements having the same characteristics to be fabricated simultaneously and thus is suitable for mass-production.
Also, it effectively equalises the characteristics of a pair of elements necessar for a catalytic combustible gas detector.
However in the detector of the above configuration, there are several problems.
In particular. the stability of the catalyst is not good because the catalyst is directly formed on the heat-resistive insulation layer, and the sensitivity and accuracy drop if the detector is continuously used for a prolonged period (e.g., for tens of days) SUMMARY OF THE INVENTION
In view of these problems, the objective of the present invention is to provide a catalytic combustible gas sensor that has a stable catalyst, high accuracy and long life.
The present invention solves the above problems by providing a catalytic combustible gas sensor having a measuring element and a reference element, wherein a catalyst is stuck to the measuring element through woven fabric or non-woven fabric.
Particular and preferred embodiments of the invention are set forth in the claims appended hereto.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 shows an exploded view of an embodiment of the measuring element for the catalytic combustible gas sensor according to the present invention
Figure 2 shows a drawing indicating a catalytic combustible gas sensor configured by providing a measuring element and a reference element as a pair.
Figure 3 shows a drawing indicating other embodiments of the present invention.
Figure 4 shows a drawing indicating further embodiments of the present invention
Figure 5 shows a drawing indicating a response curve to CO gas of a sensor fabricated according to the present invention
Figure 6 shows a drawing of the relationship between the output values to CO gas of the sensors fabricated according to the present invention and the number of elapsed days.
Figure 7 shows a drawing indicating another embodiment of the present invention in which the measuring element is formed in a rod shape.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Figure 1 shows an exploded view indicating an embodiment of the present invention. In Figure 1, platinum vapour-deposited pattern 2 that functions as a resistance thermometer is formed on the surface of ceramic substrate 1 by means of vapour deposition. On this platinum vapour-deposited pattern 2, glass protective layer 3 that functions as an insulation layer is formed, and holes 5 for attaching electrode lead wires 4 are formed at the portions corresponding to the terminals of resistance thermometer 2.
Both electrode lead wires 4 and platinum vapour-deposited pattern 2 are fused with glass for fixing lead wires 6. Catalyst sheet 7 is constructed with ceramic or glass porous material typically by woven fabric or non-woven fabric (ceramic paper) composed of ceramic or glass fibres. The thickness of this catalyst sheet 7 is approximately 0. 1 mm to 0.5 mm and the fibres are formed porously, the effective diameter of holes being 5 to 30 clam.
In addition, the catalyst sheet is formed such that its size fully covers the portion of platinum vapour-deposited pattern 2 and is herein formed to a size nearly equal to that of the ceramic substrate (approximately 3 mm by 8 mm in the embodiment).
Catalyst sheet 7 is fabricated, for example, by impregnating the sheet with a mixed solution of chloroplatinic acid and palladium chloride then firing it. The catalytic sheet 7 is closely stuck to the surface on which platinum vapour-deposited pattern 2 is formed and to the rear of that substrate 2 without gaps using a ceramic adhesive
Protective layer 8 is formed on catalyst sheet 7 by covering the catalyst sheet with woven fabric of ceramic or non-woven fabric.
According to such a configuration, the concentration of a measuring gas can be measured accurately and in a stable manner for a long time. This is because the catalyst is kept fully soaked in the woven fabric or non-woven fabric (ceramic paper) composed of ceramic or glass fibres.
Figure 2 shows a catalytic combustible gas sensor constructed with abovementioned measuring element 10 and reference element 11 (reference element 11 is equal to the above-mentioned measuring element without the catalyst sheet) fabricated as a pair
These two elements 10 and 11 are arranged close to each other and are supported by electrode lead wires 4 and the lead wires for hermetic seal parts 13
Accordingly, electrode lead wires 4 are led out through hermetic seal parts 13 press-fitted airtightly into sensor base disk 12. The outer periphery of sensor base disk 12 is fixed airtightly to sensor housing 14. and stainless steel mesh 15 is provided covering two elements 10 and 11.
According to the above configuration, the error caused by gas leakage from the lead-out portion of the lead wires of sensors 10 and 11 and corrosion inside the analyser due to corrosive gas leakage can be prevented.
Figure 3 shows side views of the other embodiments of the present invention.
The same symbols are used for elements having the same functions as in Figure 1 In this embodiment, measuring element 10 is formed on one face of insulation substrate 1 and reference element 11 is formed on the other face of insulation substrate 1. According to such a configuration, the sensor size can be reduced.
In such a configuration, heat generated on the side of measuring element 10 may cause a measuring error by being propagated to the side of reference element 11.
However, the error can be eliminated by correcting the heat propagation by measuring the relationship between the heat generation corresponding to gas concentration and the heat propagation in advance As countermeasures to heat propagation, an air gap or a heatinsulating material can be provided between two ceramic substrates 1. or the influence of heat propagation can also be reduced by placing the two elements offset from each other.
Figure 3 (a) shows an embodiment in which measuring element 10 and reference element 11 are formed opposite each other on the front and rear faces of ceramic substrate 1 respectively. Figure 3 (b) shows an embodiment in which two ceramic substrates are attached to each other with spacers inserted between them, thereby providing heat insulator (air gap) 20. Figure 3 (c) shows an embodiment in which measuring element 10 and reference element 11 are formed in positions offset from each other Figure 3 (d) shows an embodiment in which measuring element 10 and reference element 11 are formed in positions offset from each other and, in addition, a narrow part is provided between the two elements
Figure 4 shows further the other embodiments of the present invention Figure 4 (a) illustrates an embodiment in which measuring element 10 and reference element 11 are provided on the same surface of ceramic substrate 1 Figure 4(b) illustrates an embodiment in which an insulating material 20 (slit) is formed between the two elements
In addition, the air gap may be either a narrow part or a slit in Figures 3(b, d) and 4(b).
That is, the air gap can take any shape as long as heat on the side of measuring element 10 does not propagate to the side of reference element 11 and the required mechanical strength is maintained.
Figure 5 shows a graph of the response curve of a catalytic combustible gas sensor fabricated according to the present invention when the sensor is placed in an atmosphere containing 1000 ppm of CO gas heated to about 300"C. In the graph, the sensor output is on the vertical axis and the time (minutes) on the horizontal axis. This response curve shows that the response speed of the sensor is very fast because the sensor output reaches its maximum within about 10 seconds from the start of measurement. In addition, around 2 minutes after the supply of CO gas stops at point A.
Figure 6 is a graph of the outputs of five sensors fabricated according to the present invention, the sensor output being on the vertical axis and the number of elapsed days being on the horizontal axis. The five sensors are heated to around 280"C and are contacted with a gas containing SO2 gas: 2000 ppm, H2O: 18%, 02: about 10% The sensor output is then measured every ten days in an atmosphere of the foregoing composition to which CO gas: 1000 ppm has been added.
The graph indicates that all five trial-produced sensors suffered no deterioration in accuracy and sensitivity even after about 200 days from the start of measurement, and can measure the gas in a stable manner for a long time.
In addition, around 0.3V of output fluctuations are caused by evaporation in a humidifier provided in a constant temperature chamber.
Figure 7 illustrates another embodiment of the present invention, in which measuring element 10 is formed in a rod shape. In this embodiment, a coil-shaped platinum resistance element (not shown in the figure) is embedded in ceramic la formed in a rod shape. As a means to stick a catalyst to the outer periphery of this rod-type ceramic la, woven fabric or non-woven fabric (catalyst tube 7a) similar to the aforementioned one is provided. In this case, an element without catalyst tube 7a is used as a reference element.
In such a shape, for example, a mixed solution of chloroplatinic acid and palladium chloride can be used as the catalyst. A catalyst sheet can be fabricated bv soaking woven fabric or non-woven fabric of ceramic or glass fibre with the mixed solution and then baking it. The catalyst tube 7a is then stuck closely to the outer periphery of rod-type ceramic la without gaps using a ceramic adhesive.
In such a configuration, the concentration of a measuring gas can also be measured accurately and in a stable manner for a long time because the catalyst remains fully soaked in the woven fabric or non-woven fabric composed of ceramic or glass fibres.
In addition, the above description of the present invention is only illustrative for specific preferred embodiments for the purpose of explanation and giving examples, and is not restrictive. Accordingly, it is apparent to those skilled in the art that many changes and modifications may be made without departing from the essential characteristics thereof. The scope of the invention is defined by the claims and all changes and modifications, which come within the range of equivalency of the claims are intended to be included therein.
Claims (19)
1. A catalytic combustible gas sensor having a measuring element and a reference
element, wherein a catalyst is stuck to the measuring element through woven fabric or non-woven fabric.
2. A catalytic combustible gas sensor according to Claim 1, wherein a measuring element and a reference element are formed on the front and rear faces of an insulator substrate respectively
3. A catalytic combustible gas sensor according to Claim 2, wherein a heat-insulator is inserted at the middle of the thickness of said insulator substrate.
4. A catalytic combustible gas sensor according to Claim 1, wherein a pair of elements constituted by a measuring element and reference element are formed on the same surface of said insulator substrate.
5. A catalytic combustible gas sensor according to Claim 4, wherein a heatinsulating zone is provided between said measuring element and said reference element.
6. A catalytic combustible gas sensor according to Claim 5, wherein said heatinsulating zone is defined by a space formed between said measuring element and said reference element.
7. A catalytic combustible gas sensor according to Claims 2 or 4, wherein said insulator substrate is made of ceramic.
8. A catalytic combustible gas sensor having a catalyst-formed measuring element and a reference element, wherein the measuring element is embedded in a rod-shaped ceramic which forms a resistance element and a catalyst is stuck on the outside periphery of this rod-shaped ceramic through woven fabric or non-woven fabric
9. A catalytic combustible gas sensor according to Claims 1 or 8, wherein said woven fabric or non-woven fabric consists of ceramic or glass fibres.
10. A catalytic combustible gas sensor according to Claims 1 or 8, wherein the thickness of said woven fabric or non-woven fabric is approximately 0 1 mm to 0 5 mm
11 A catalytic combustible gas sensor according to Claims 1 or 8, wherein fibres used for said woven fabric or said non-woven fabric are formed porously, the effective diameter of such holes being 5 to 30 Clam.
12. A catalytic combustible gas sensor according to Claims 1 or 8, wherein said woven fabric or non-woven fabric is formed such that its size fully covers the portion forming said resistance element constructing said measuring element and is also stuck closely to the measuring element without gaps.
13. A catalytic combustible gas sensor according to Claims 1 or 8, wherein a ceramic adhesive is used as a means to closely stick woven fabric or non-woven fabric to said measuring element.
14 A catalytic combustible gas sensor according to Claims 1 or 8, wherein said catalyst is formed by sticking a precious metal. such as platinum, palladium or rhodium, as well as baking it to said woven fabric or non-woven fabric.
15. A catalytic combustible gas sensor according to Claims 1 or 8, wherein said catalyst is formed by impregnating woven fabric or non-woven fabric with a mixed solution of chloroplatinic acid and palladium chloride and then firing the impregnated mixture
16. A catalytic combustible gas sensor according to Claims 1 or 8, wherein the upper surface of said measuring element where a catalyst is formed is covered with non-woven fabric of activated carbon.
17. A catalytic combustible gas sensor according to Claims 1, 2, 4 or 8, wherein lead wires from said measuring element and said reference element are extended via hermetic seal parts
18. A catalytic combustible gas sensor according to Claim 17, wherein said hermetic seal parts are fixed to a base disk and this base disk is fixed airtight to a sensor housing
19. A catalytic gas sensor having a measuring element and a reference element: wherein a catalyst carried on a woven or non-woven fabric is bonded (e.g stuck) to the measuring element.
20 A catalytic gas sensor having a measuring element and a reference element wherein a catalyst sheet comprising a catalyst and a woven or non-woven fabric support is bonded (e.g. stuck) to the measuring element.
21 A catalytic gas sensor according to Claim 20 wherein the catalyst sheet is bonded to the measuring element by a ceramic adhesive 22 A catalytic gas sensor according to Claims 19. 20 or 21. wherein the measuring element, reference element. woven or non-woven fabric and catalyst are as defined in anv one ofClaims 1 to 18 23. A catalytic gas sensor substantially as described herein with reference to the accompanying drawings.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10026147A JPH11223614A (en) | 1998-02-06 | 1998-02-06 | Contact combustion type inflammable gas sensor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB9901242D0 GB9901242D0 (en) | 1999-03-10 |
| GB2334105A true GB2334105A (en) | 1999-08-11 |
Family
ID=12185441
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9901242A Withdrawn GB2334105A (en) | 1998-02-06 | 1999-01-20 | Catalytic combustible gas sensor |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JPH11223614A (en) |
| GB (1) | GB2334105A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102539489A (en) * | 2012-02-09 | 2012-07-04 | 中国矿业大学 | Packaging structure for catalytic combustion type gas sensitive element |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4666243B2 (en) * | 2000-09-18 | 2011-04-06 | 横河電機株式会社 | Combustible gas meter |
| JP2007248197A (en) * | 2006-03-15 | 2007-09-27 | Riken Keiki Co Ltd | Contact combustion type gas sensor |
| JP5138404B2 (en) * | 2008-02-05 | 2013-02-06 | アズビル株式会社 | Gas sensor chip and gas sensor having the same |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3895912A (en) * | 1974-11-06 | 1975-07-22 | Nasa | Carbon monoxide monitor |
| US4077775A (en) * | 1975-12-05 | 1978-03-07 | Comptoir Lyon-Alemand-Louyot | Element for detecting the presence of combustible gases in a gaseous atmosphere |
| SU1068793A1 (en) * | 1982-07-14 | 1984-01-23 | Куйбышевский ордена Трудового Красного Знамени политехнический институт им.В.В.Куйбышева | Thermochemical detector |
| WO1991019975A1 (en) * | 1990-06-12 | 1991-12-26 | Catalytica, Inc. | NOx SENSOR ASSEMBLY |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5121895A (en) * | 1974-08-13 | 1976-02-21 | Matsushita Electric Works Ltd | GASUKENCHISOSHI |
| JPS5121894A (en) * | 1974-08-13 | 1976-02-21 | Matsushita Electric Works Ltd | GASUKENCHISOSHI |
| JPS54121794A (en) * | 1978-03-15 | 1979-09-21 | Hitachi Ltd | Hightemperature operation sensor |
| JPS56168149A (en) * | 1980-05-29 | 1981-12-24 | Toyota Motor Corp | Detecting method for content of carbon monoxide |
| JPH0949819A (en) * | 1995-08-09 | 1997-02-18 | Fuji Electric Co Ltd | Carbon monoxide detector |
-
1998
- 1998-02-06 JP JP10026147A patent/JPH11223614A/en active Pending
-
1999
- 1999-01-20 GB GB9901242A patent/GB2334105A/en not_active Withdrawn
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3895912A (en) * | 1974-11-06 | 1975-07-22 | Nasa | Carbon monoxide monitor |
| US4077775A (en) * | 1975-12-05 | 1978-03-07 | Comptoir Lyon-Alemand-Louyot | Element for detecting the presence of combustible gases in a gaseous atmosphere |
| SU1068793A1 (en) * | 1982-07-14 | 1984-01-23 | Куйбышевский ордена Трудового Красного Знамени политехнический институт им.В.В.Куйбышева | Thermochemical detector |
| WO1991019975A1 (en) * | 1990-06-12 | 1991-12-26 | Catalytica, Inc. | NOx SENSOR ASSEMBLY |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102539489A (en) * | 2012-02-09 | 2012-07-04 | 中国矿业大学 | Packaging structure for catalytic combustion type gas sensitive element |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH11223614A (en) | 1999-08-17 |
| GB9901242D0 (en) | 1999-03-10 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |