WO2014142829A1 - Gas sensors and methods of calibrating same - Google Patents
Gas sensors and methods of calibrating same Download PDFInfo
- Publication number
- WO2014142829A1 WO2014142829A1 PCT/US2013/030840 US2013030840W WO2014142829A1 WO 2014142829 A1 WO2014142829 A1 WO 2014142829A1 US 2013030840 W US2013030840 W US 2013030840W WO 2014142829 A1 WO2014142829 A1 WO 2014142829A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- medium
- heat flux
- species
- sensor
- methane
- Prior art date
Links
- 238000000034 method Methods 0.000 title claims abstract description 29
- 230000004907 flux Effects 0.000 claims abstract description 33
- 238000005259 measurement Methods 0.000 claims abstract description 8
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 claims description 87
- 239000000203 mixture Substances 0.000 claims description 23
- ATUOYWHBWRKTHZ-UHFFFAOYSA-N Propane Chemical compound CCC ATUOYWHBWRKTHZ-UHFFFAOYSA-N 0.000 claims description 12
- 239000001294 propane Substances 0.000 claims description 6
- OTMSDBZUPAUEDD-UHFFFAOYSA-N Ethane Chemical compound CC OTMSDBZUPAUEDD-UHFFFAOYSA-N 0.000 claims description 5
- 239000003570 air Substances 0.000 description 20
- 239000007789 gas Substances 0.000 description 11
- 239000012080 ambient air Substances 0.000 description 5
- 230000014509 gene expression Effects 0.000 description 4
- 238000001514 detection method Methods 0.000 description 3
- 230000008569 process Effects 0.000 description 3
- 230000006978 adaptation Effects 0.000 description 2
- 230000007246 mechanism Effects 0.000 description 2
- 239000003345 natural gas Substances 0.000 description 2
- 230000004044 response Effects 0.000 description 2
- 206010003497 Asphyxia Diseases 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000010411 cooking Methods 0.000 description 1
- 238000004880 explosion Methods 0.000 description 1
- 230000006870 function Effects 0.000 description 1
- 239000008246 gaseous mixture Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 231100000252 nontoxic Toxicity 0.000 description 1
- 230000003000 nontoxic effect Effects 0.000 description 1
- 230000009965 odorless effect Effects 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 230000009967 tasteless effect Effects 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/0004—Gaseous mixtures, e.g. polluted air
- G01N33/0006—Calibrating gas analysers
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N25/00—Investigating or analyzing materials by the use of thermal means
- G01N25/18—Investigating or analyzing materials by the use of thermal means by investigating thermal conductivity
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/22—Fuels; Explosives
- G01N33/225—Gaseous fuels, e.g. natural gas
Definitions
- the invention relates to sensors for detecting the presence of a target species in a gaseous medium and, more particularly, to methods of calibrating thermal conductivity sensors for measuring the concentration of methane (CH 4 ) in air.
- Methane is a common gas that makes up a large proportion of natural gas, which is used for heating, cooking, and other applications. In its naturally occurring state, methane is odorless, tasteless, colorless, and non-toxic. In an enclosed space, however, methane may cause suffocation, if it displaces oxygen. Methane is also flammable and presents a risk of explosion if the gas is not detected and/or controlled.
- One type of methane detector includes a thermal conductivity sensor that detects methane by measuring the thermal conductivity of a gaseous mixture. It is a universal practice to calibrate this sensor with pure methane. Calibration with pure methane requires an available methane supply and equipment for storing and delivering it. Also, suitable precautions (e.g. a laboratory exhaust hood, odorization, etc.) must be taken since pure methane raises potential safety concerns.
- embodiments of the present invention feature a method of calibrating a thermal conductivity sensor for detecting a target species in a gaseous medium. Unlike previous methods that require the use of the pure target species (e.g., pure methane), embodiments of the method described herein utilize only ambient air for calibration.
- pure target species e.g., pure methane
- the new method is generally safer, less expensive and easier to perform. Furthermore, it can be performed anywhere, in the field as well as in a laboratory, thereby making field measurements more reliable.
- embodiments of the invention relate to a method of calibrating a thermal conductivity sensor in a first medium A from measurements in a second medium B.
- the method includes maintaining the sensor at a substantially fixed temperature Tj, and measuring a heat flux (Ti) in the second medium B.
- a corresponding heat flux IA(TI) in the first medium A is calculated using known thermal conductivities of the first medium A and the second medium B.
- the first medium A includes methane, ethane, or propane
- the second medium B is or includes air.
- the fixed temperature Ti may be, for example, in a range from about 70 °C to about 300 °C.
- the method also includes: measuring a heat flux IM ⁇ TI) of the thermal conductivity sensor in a mixture of a species 3 ⁇ 4 and the second medium B, the species 3 ⁇ 4 corresponding to the first medium A; and calculating a concentration CA of the species 3 ⁇ 4 in the mixture according to [0008]
- embodiments of the invention relate to a thermal conductivity sensor for measuring a concentration CA of a species SA in a mixture of the species SA and a medium B.
- the sensor includes a thermal element and a processor.
- the processor is configured to execute instructions to: maintain the thermal element at a substantially fixed temperature T , measure a heat flux (Ti) from the thermal element in the medium B; and calculate a heat flux IA(TI) from the thermal element in the species 3 ⁇ 4.
- the heat flux IA(TI) corresponds to the fixed temperature Tj of the thermal element.
- the heat flux IA(TI) is calculated based on the heat flux IB(TI) and thermal conductivities of the species 3 ⁇ 4 and the medium B at the fixed temperature Tj.
- the species SA includes methane, ethane, or propane, and the medium B includes air.
- the fixed temperature Tj may be in a range from, for example, about 70 °C to about 300 °C.
- the processor is configured to execute instructions to: measure a heat flux IM(TI) from the thermal element in a mixture of the species SA and the medium B; and calculate a concentration CA of the species 3 ⁇ 4 in the mixture according to
- FIG. 1 is a schematic, side, cross-sectional view of a thermal conductivity sensor having a thermal element and a heat sink, in accordance with an illustrative embodiment of the invention
- FIG. 2 is a schematic, top view of a thermal conductivity sensor having a thermal element and a heat sink, in accordance with an illustrative embodiment of the invention.
- FIG. 3 is a plot of sensor gain versus heat flux through air, for a thermal conductivity sensor, in accordance with an illustrative embodiment of the invention.
- apparatus, systems, methods, and processes of the claimed invention encompass variations and adaptations developed using information from the embodiments described herein. Adaptation and/or modification of the apparatus, systems, methods, and processes described herein may be performed by those of ordinary skill in the relevant art.
- the devices and methods described herein relate to the detection of a target species (e.g., methane) in a gaseous medium or mixture (e.g., air).
- Detection of the target species is understood to include or consist essentially of detecting the presence of the target species in the mixture and/or measuring a concentration (e.g., a volume or mole percent) of the target species in the mixture.
- the target species may be any type of gaseous species, including, for example, methane, ethane, propane, or natural gas.
- a particular target species is methane.
- the gaseous medium may include any gaseous species and in particular ambient air.
- Wheatstone Bridge or a similar electronic device is used for the measurements.
- thermal conductivity sensors may be accurately calibrated using ambient air, rather than pure methane, as the calibration gas.
- the calibration methods described herein may include predicting a response of the thermal conductivity sensor in a first medium (e.g., methane) based on measurements obtained in a second medium (e.g., ambient air).
- FIGS. 1 and 2 depict a thermal conductivity sensor 10 for measuring a concentration C of a target species (e.g., methane) in a mixture of gases (e.g., methane and air), in accordance with certain embodiments of the invention.
- the sensor includes a wire or thermal element 12 having an outer radius rj surrounded by a concentric heat sink 14 having an inner radius ro. A region 16 between the thermal element 12 and the heat sink 14 is occupied by the gas mixture.
- the sensor 10 measures a conductive heat transfer rate through the mixture, from thermal element 12 to the heat sink 14.
- the thermal element 12 and/or the heat sink 14 may have any shape.
- the thermal element 12 and/or the heat sink 14 may be substantially flat, curved, cylindrical, spherical, and/or combinations thereof. In the depicted embodiment, the thermal element and the heat sink are substantially cylindrical.
- heat flux values within the sensor may be measured using any available technique.
- a simple way is to measure the power required to keep the thermal element at a fixed temperature.
- the conductive heat flux, /, from the thermal element 12 to the heat sink 14 may be expressed as
- T is the temperature
- / is the length of the wire
- K is the thermal conductivity of the medium. This last quantity is a bulk thermodynamic property of the medium, independent of the particular construction of the sensor. If the medium is air, the gas of interest (i.e., the target species) methane, and no other gases are present in significant quantities, and noting that methane and air form simple mixtures, the thermal conductivity of a methane and air mixture is
- CA and Cg are mole fractions of methane and air
- KA and KB are thermal conductivities of pure methane and air, respectively.
- the quantity I A — I B is referred to as the Gain of the sensor.
- the measured heat flux h in air may be used to compute the sensor's response in pure methane, thereby making calibration with pure methane unnecessary.
- the sensors described herein include a memory that can be read by a processor.
- the memory may include computer storage media in the form of volatile and/or nonvolatile memory such as read only memory (ROM) and random access memory (RAM).
- the processor executes instructions that are stored in order to process data and carry out the methods described herein.
- the set of instructions may include various instructions that perform a particular task or tasks. Such a set of instructions for performing a particular task may be characterized as a program, software program, software, engine, module, component, mechanism, or tool.
Landscapes
- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Biochemistry (AREA)
- Pathology (AREA)
- Immunology (AREA)
- General Physics & Mathematics (AREA)
- General Health & Medical Sciences (AREA)
- Physics & Mathematics (AREA)
- Analytical Chemistry (AREA)
- Medicinal Chemistry (AREA)
- Food Science & Technology (AREA)
- Combustion & Propulsion (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- General Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Investigating Or Analyzing Materials Using Thermal Means (AREA)
Abstract
Description
Claims
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB1516360.3A GB2526039B (en) | 2013-03-13 | 2013-03-13 | Gas sensors and methods of calibrating same |
DE112013006685.8T DE112013006685B4 (en) | 2013-03-13 | 2013-03-13 | Gas sensors, method and device for calibrating the same |
PCT/US2013/030840 WO2014142829A1 (en) | 2013-03-13 | 2013-03-13 | Gas sensors and methods of calibrating same |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
PCT/US2013/030840 WO2014142829A1 (en) | 2013-03-13 | 2013-03-13 | Gas sensors and methods of calibrating same |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2014142829A1 true WO2014142829A1 (en) | 2014-09-18 |
Family
ID=48142920
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US2013/030840 WO2014142829A1 (en) | 2013-03-13 | 2013-03-13 | Gas sensors and methods of calibrating same |
Country Status (3)
Country | Link |
---|---|
DE (1) | DE112013006685B4 (en) |
GB (1) | GB2526039B (en) |
WO (1) | WO2014142829A1 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP3521816A1 (en) * | 2018-02-06 | 2019-08-07 | L'air Liquide Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude | Method for in-situ monitoring of the quality of gas delivered to a consuming industrial site using the thermal conductivity technique |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4859078A (en) * | 1986-02-07 | 1989-08-22 | Massachusetts Institute Of Technology | Apparatus for the non-invasive measurement of thermal properties and perfusion rates of biomaterials |
US4970891A (en) * | 1989-12-26 | 1990-11-20 | Ethyl Corporation | Apparatus for measuring gaseous impurity in solids |
US5311447A (en) * | 1991-10-23 | 1994-05-10 | Ulrich Bonne | On-line combustionless measurement of gaseous fuels fed to gas consumption devices |
US20110077872A1 (en) * | 2009-09-29 | 2011-03-31 | Lawrence Livermore National Security, Llc | Microcantilever-based gas sensor employing two simultaneous physical sensing modes |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP3114139B2 (en) * | 1995-01-24 | 2000-12-04 | 株式会社山武 | Thermal conductivity meter |
DE19519076A1 (en) | 1995-05-18 | 1996-11-28 | Mannesmann Ag | Calibrating gas analysers esp. oxygen analysers for re-calibrating between measurements |
-
2013
- 2013-03-13 GB GB1516360.3A patent/GB2526039B/en active Active
- 2013-03-13 DE DE112013006685.8T patent/DE112013006685B4/en active Active
- 2013-03-13 WO PCT/US2013/030840 patent/WO2014142829A1/en active Application Filing
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4859078A (en) * | 1986-02-07 | 1989-08-22 | Massachusetts Institute Of Technology | Apparatus for the non-invasive measurement of thermal properties and perfusion rates of biomaterials |
US4970891A (en) * | 1989-12-26 | 1990-11-20 | Ethyl Corporation | Apparatus for measuring gaseous impurity in solids |
US5311447A (en) * | 1991-10-23 | 1994-05-10 | Ulrich Bonne | On-line combustionless measurement of gaseous fuels fed to gas consumption devices |
US20110077872A1 (en) * | 2009-09-29 | 2011-03-31 | Lawrence Livermore National Security, Llc | Microcantilever-based gas sensor employing two simultaneous physical sensing modes |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP3521816A1 (en) * | 2018-02-06 | 2019-08-07 | L'air Liquide Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude | Method for in-situ monitoring of the quality of gas delivered to a consuming industrial site using the thermal conductivity technique |
WO2019154697A1 (en) * | 2018-02-06 | 2019-08-15 | L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude | Method for on-site testing of the quality of gases delivered to a industrial consumer site, using a thermal conductivity technique |
US11460422B2 (en) | 2018-02-06 | 2022-10-04 | L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude | Method for on-site monitoring of the quality of the gases delivered to an industrial consumer site using the thermal conductivity technique |
Also Published As
Publication number | Publication date |
---|---|
GB2526039B (en) | 2017-12-06 |
DE112013006685B4 (en) | 2022-06-15 |
DE112013006685T5 (en) | 2015-10-29 |
GB2526039A (en) | 2015-11-11 |
GB201516360D0 (en) | 2015-10-28 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US20110079074A1 (en) | Hydrogen chlorine level detector | |
US20150075256A1 (en) | Multiple gas sensor | |
CN106940205B (en) | Calibration method for humidity sensor in high-humidity environment | |
CN110988272A (en) | Method for correcting measured values of a hydrogen sensor | |
US20200088669A1 (en) | Method for Operating a Sensor Device | |
Nenova et al. | Compensation of the impact of disturbing factors on gas sensor characteristics | |
CN105157844B (en) | A kind of thermodynamic temperature measurement method of nuclear radiation environment | |
CN106092375B (en) | The method of calibration and tester of airborne equipment surface temperature sensor | |
CN109564178A (en) | Heating-value determination device and method | |
CN111272836A (en) | Interference-free gas measurement | |
CN105319240A (en) | Sensor device for sensing humidity of fluid medium | |
Sairanen et al. | Validation of a calibration set-up for radiosondes to fulfil GRUAN requirements | |
WO2014142829A1 (en) | Gas sensors and methods of calibrating same | |
EP3186622B1 (en) | Method for analyzing an ozone concentration and ozone concentration analyzer | |
JP5811406B2 (en) | Humidity measuring device and humidity measuring method | |
US9121773B2 (en) | Gas sensors and methods of calibrating same | |
CN113518914A (en) | Concentration measuring device | |
CN114184648B (en) | Moisture content calibration method for resistance-capacitance humidity sensor | |
Rupnik et al. | A method for gas identification in thermal dispersion mass flow meters | |
KR102301888B1 (en) | Temperature conpensation method for calibrating of gas sensor module using change of heater current | |
Collings et al. | Estimating IC engine exhaust gas lambda and oxygen from the response of a universal exhaust gas oxygen sensor | |
JP5844556B2 (en) | Method for correcting output of heat conduction type gas sensor and gas detector | |
Lourenço et al. | Isobaric specific heat capacity of water and aqueous cesium chloride solutions for temperatures between 298 K and 370 K at p= 0.1 MPa | |
Sahoo | An approach to LabVIEW based temperature & relative humidity monitoring system | |
Goshlya et al. | The application of compact thermistors for the temperature conditions analysis of small-sized long-stroke low-speed stages of piston compressors |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
121 | Ep: the epo has been informed by wipo that ep was designated in this application |
Ref document number: 13717596 Country of ref document: EP Kind code of ref document: A1 |
|
WWE | Wipo information: entry into national phase |
Ref document number: 112013006685 Country of ref document: DE Ref document number: 1120130066858 Country of ref document: DE |
|
ENP | Entry into the national phase |
Ref document number: 1516360 Country of ref document: GB Kind code of ref document: A Free format text: PCT FILING DATE = 20130313 |
|
WWE | Wipo information: entry into national phase |
Ref document number: 1516360.3 Country of ref document: GB |
|
122 | Ep: pct application non-entry in european phase |
Ref document number: 13717596 Country of ref document: EP Kind code of ref document: A1 |