WO1999017110A1 - Detecteur de gaz combustible a generateur d'hydrogene integre - Google Patents

Detecteur de gaz combustible a generateur d'hydrogene integre Download PDF

Info

Publication number
WO1999017110A1
WO1999017110A1 PCT/US1998/019844 US9819844W WO9917110A1 WO 1999017110 A1 WO1999017110 A1 WO 1999017110A1 US 9819844 W US9819844 W US 9819844W WO 9917110 A1 WO9917110 A1 WO 9917110A1
Authority
WO
WIPO (PCT)
Prior art keywords
combustible gas
sensor
hydrogen generator
gas sensor
combustible
Prior art date
Application number
PCT/US1998/019844
Other languages
English (en)
Inventor
Raymond B. Cromer
Stephen D. Summerfield
Matthew S. Fitzgerald
Original Assignee
Analytical Technology, Inc.
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Analytical Technology, Inc. filed Critical Analytical Technology, Inc.
Publication of WO1999017110A1 publication Critical patent/WO1999017110A1/fr

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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
    • 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
    • G01N33/0009—General constructional details of gas analysers, e.g. portable test equipment
    • G01N33/0027—General constructional details of gas analysers, e.g. portable test equipment concerning the detector
    • G01N33/0036—General constructional details of gas analysers, e.g. portable test equipment concerning the detector specially adapted to detect a particular component
    • G01N33/0047—Organic compounds

Definitions

  • This invention relates to a method and apparatus for automatically testing the response of combustible gas sensors and more particularly to a combustible gas sensor with integral hydrogen generator.
  • Combustible gas sensors have been used for over fifty years to detect the presence of potentially hazardous concentrations of flammable gases or vapors. They are widely used in industry for safety purposes, providing a warning of potentially hazardous conditions before gas levels reach explosive levels.
  • Commercial combustible gas sensors detect gases through the use of a heated catalytic element. When a combustible gas or vapor comes in contact with this element, the gas or vapor is burned, causing an increase in heat on that element. The resistance of the catalytic element changes in proportion to the combustion heat, and the resistance change is compared to a similar but inert reference element.
  • the catalytic element and the reference element form two legs of a simple Wheatstone bridge circuit which measures the resistance change caused by the presence of combustible gases and vapors.
  • Combustible gas detectors are well known in the art and are described by Warren J. Reilly in an article entitled “Combustible Gas Detectors” based on a paper delivered at the Arrowspace/Test Measurement Conference, Philadelphia, 1975.
  • the combustible gas sensing system of the present invention provides the automatic checking of the combustible sensor every twenty four hours and greatly reduces the manual labor needed to verify that the gas detection system is operable and will respond in the event of gas leakage.
  • the present invention is intended to obviate the above- described problems and has for its object to provide a system for verifying the response of a combustible gas sensor by combining the combustible gas sensor with an integral hydrogen generator in one explosion-proof assembly.
  • the present invention provides an electrochemical hydrogen generator capable of delivering relative high H 2 concentrations (needed to properly test this type of sensor) to the combustible sensor, and integrating the generator into the sensor itself.
  • the result is a device that includes both the sensor and a mechanism for automatically testing that sensor to detect loss of sensitivity.
  • an assembly for verifying the response of a combustible gas sensor including an explosion proof housing including a catalytic combustible gas sensor having active and passive sensing elements disposed within the housing.
  • a hydrogen generator is disposed within the housing and separated from the catalytic combustible gas sensor by a gas diffusion chamber.
  • the gas diffusion chamber has an opening in the wall of the explosion proof housing to allow combustible gases in the ambient air to diffuse to the sensing elements of the catalytic combustible sensor.
  • a sintered metal flame arrestor separates the combustible gas sensing elements from the combustible gas chamber and a sintered metal flame arrestor separates the hydrogen generator from the combustible gas chamber.
  • the hydrogen generator includes an electrochemical cell containing two embedded electrodes and a water based electrolyte, the electrolyte being a hygroscopic acid retained within a porous plastic medium within the hydrogen generator so that when water is electrolyzed to produce hydrogen, the water that is lost is replenished by the humidity in the ambient air to insure sufficient water for the hydrogen generation process over an extended period of time.
  • a method including the steps of energizing the hydrogen generator of the aforesaid type to deliver a hydrogen test sample to produce a concentration above a predetermined lower explosive limit (LEL) within the gas diffusion chamber, causing the test gas to pass through the sintered metal flame arrestor to a sensor cavity adjacent the catalytic combustible gas sensor, and monitoring the output of the combustible sensor during the gas generation cycle.
  • LEL lower explosive limit
  • Fig. 1 is an elevational view partly in section of a combustible gas sensor with integral hydrogen generator embodying the present invention.
  • Fig. 2 is a schematic diagram of the electrical circuit in the combustible gas sensor with integral hydrogen generator illustrated in Fig. 1.
  • the assembly includes a catalytic combustible gas sensor 12 and a hydrogen generator 14 both disposed within an explosion proof housing 16.
  • the catalytic combustible gas sensor has an active element 18 and a passive element 20.
  • the passive element 20 is sometimes referred to as a reference element and the reference element 20 and active element 18 are arranged in a Wheatstone bridge. As shown in Fig. 2 the active and passive elements 18 and 20 form two legs of the
  • the circuit also includes an adjustable resistor 26.
  • combustible gas molecules react, via a catalyst, to form oxidation products on the active (open to air) element 18 increasing its temperature and resistance.
  • the sensing elements may be either coated with a catalyst and coiled, or encased in a catalytic bead element, as well known in the art.
  • a thermal barrier 28 preferably made from Teflon, and positioned to keep the heat generated at the active element 18, when exposed to combustible gases, from transferring to the passive element 20, which does not heat up on contact with combustible gases.
  • a sintered metal flame arrestor 30 of stainless steel is positioned within the housing 16 to keep the sensing elements 18 and 20 isolated within the housing while allowing combustible gases to diffuse to a sensor cavity 32 adjacent to the sensing elements 18 and 20.
  • the hydrogen generator 14 is mounted within the lower portion of the explosion proof housing 16 and is separated from the combustible gas sensor by a gas diffusion chamber 34.
  • the gas diffusion chamber 34 has an opening 34a to the exterior of the housing 16.
  • the gas diffusion chamber 34 is bounded by the sintered metal flame arrestor 30 which isolates the sensing elements 18 and 20 of the combustible gas sensor 12 and a second sintered metal flame arrestor 36 which isolates the hydrogen generator 14 from the gas diffusion chamber.
  • the gas diffusion opening 34a allows ambient air and any combustible gases to diffuse into the chamber 34 of the housing 16 so that they are sensed by the active element 18 of the sensor.
  • the hydrogen generator 14 is an electrochemical cell containing two embedded electrodes 38 and 40, Fig. 2, and a water based electrolyte 42, Fig. 1. In operation, a 2.5 volts DC potential is placed across the electrodes 38 and 40 when the switch 44 is closed with the current being limited by resistor 46 to about 60mA.
  • water will be split into hydrogen and oxygen.
  • the hydrogen is evolved from the surface of the electrode 38 nearest the diffusion opening and is allowed to move by natural diffusion through the sintered metal flame arrestor 36, across the gas diffusion chamber 34 and through the sintered metal flame arrestor 30 into the sensor cavity 32 adjacent the sensing elements 18 and 20.
  • the hydrogen generator 14 relies on water inside the generator cell for hydrogen production. Since the generator cell must be relatively small from a packaging standpoint, the amount of water could potentially limit a number of tests that could be run prior to the generator failing. Requiring generators to be refilled with water adds a maintenance requirement that particularly negates the value of the self-check. Formulating the electrolyte so that it pulls water out of the air allows the generator to run for well over a year without any type of service. Basically, the electrolyte is a hygroscopic acid, such for example as concentrated sulfuric acid, which is retained inside a porous plastic medium similar to filter paper. When water is electrolyzed to produce hydrogen, the water that is lost is replenished by the humidity in the ambient air.
  • the hydrogen generator 14 is activated on a periodic basis under software control for a fixed period of time. As may be seen in Fig. 2, hydrogen generator is activated when the switch 44 is closed. The switch 44 is microprocessor controlled. The current to the generator 14 is controlled to deliver a hydrogen concentration above 5 % LEL (0.2% hydrogen by volume).
  • Lower explosive limit (LEL) data for common combustible gases and vapors are published by the National Fire Protection Association. The LEL is the lowest concentration of the gas, mixed with air, which will propagate a flame. In normal air, the LEL can vary from 0.6% to 12.5 % , by volume. Concentrations of gas above the LEL will propagate flame until the upper explosive limit (UEL) is reached.
  • UEL upper explosive limit
  • the output of the combustible gas sensor 12 is monitored during the gas generation cycle. If the sensor output reaches a predetermined LEL value, normally 5 % , the sensor is deemed to have passed the test and the hydrogen generator 14 is shut off. If the sensor does not reach the predetermined LEL value within a fixed time, the sensor 12 is deemed to have failed and an alarm signal is generated.
  • a predetermined LEL value normally 5 %

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  • Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Health & Medical Sciences (AREA)
  • Medicinal Chemistry (AREA)
  • Food Science & Technology (AREA)
  • Combustion & Propulsion (AREA)
  • Physics & Mathematics (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

L'invention concerne un ensemble (10) permettant de vérifier la réaction d'un détecteur de gaz combustible, lequel ensemble combine un détecteur (12) de gaz combustible catalytique et un générateur d'hydrogène (14) disposés à l'intérieur d'un carter antidéflagrant (16).
PCT/US1998/019844 1997-10-01 1998-09-24 Detecteur de gaz combustible a generateur d'hydrogene integre WO1999017110A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US94208397A 1997-10-01 1997-10-01
US08/942,083 1997-10-01

Publications (1)

Publication Number Publication Date
WO1999017110A1 true WO1999017110A1 (fr) 1999-04-08

Family

ID=25477550

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1998/019844 WO1999017110A1 (fr) 1997-10-01 1998-09-24 Detecteur de gaz combustible a generateur d'hydrogene integre

Country Status (1)

Country Link
WO (1) WO1999017110A1 (fr)

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2356708A (en) * 1999-11-27 2001-05-30 Central Research Lab Ltd Sensor system with self-test facility
WO2005119248A1 (fr) * 2004-05-28 2005-12-15 Honeywell International Inc. Dispositif d'etalonnage pour systemes de controle de gaz
WO2006060320A2 (fr) * 2004-11-30 2006-06-08 Honeywell International Inc. Hydrures metalliques nano-crystallins et/ou metastables utilises comme source d'hydrogene a des fins d'etalonnage de capteurs et d'autodiagnostic
WO2006063183A2 (fr) * 2004-12-08 2006-06-15 Honeywell International Inc. Systeme de detection electrochimique
US7111493B2 (en) 2002-11-26 2006-09-26 Proton Energy Systems, Inc. Combustible gas detection system
US7159444B2 (en) 2002-11-26 2007-01-09 Proton Energy Systems, Inc. Combustible gas detection systems and method thereof
US7174766B2 (en) 2005-05-24 2007-02-13 Honeywell International Inc. Calibration device for carbon dioxide sensor
US8826724B2 (en) 2010-12-24 2014-09-09 Honeywell International Inc. Carbon dioxide sensor
DE102015015152A1 (de) 2015-11-25 2017-06-01 Dräger Safety AG & Co. KGaA Verfahren zur Überprüfung eines Gassensors in einem Gasmesssystem
EP3220142A1 (fr) 2016-03-18 2017-09-20 Dräger Safety AG & Co. KGaA Procédé de vérification d'un capteur de gaz et dispositif de mesure de gaz, détecteur de gaz comprenant un dispositif de vérification d'un capteur de gaz
EP3220141A1 (fr) 2016-03-18 2017-09-20 Dräger Safety AG & Co. KGaA Procédé de vérification d'un capteur de gaz et dispositif de mesure de gaz, détecteur de gaz comprenant un dispositif de vérification d'un capteur de gaz
DE102016013959A1 (de) 2016-11-23 2018-05-24 Drägerwerk AG & Co. KGaA Prüfvorrichtung zu einer Überprüfung eines Gasführungselementes
DE102016013958A1 (de) 2016-11-23 2018-05-24 Drägerwerk AG & Co. KGaA Vorrichtung mit einer Pumpeinrichtung zu einer Überprüfung einer Funktionsbereitschaft eines Gasführungselementes eines Gasmesssystems

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4155712A (en) * 1976-04-12 1979-05-22 Taschek Walter G Miniature hydrogen generator
US4332664A (en) * 1980-09-09 1982-06-01 Csepel Muvek Hiradastechnikai Gepgyara Gas producing electrolytic cell for portable devices
US4391682A (en) * 1980-02-11 1983-07-05 Kernforschungsanlage Julich Gmbh Method for electrolytic production of hydrogen
US4489590A (en) * 1982-01-25 1984-12-25 Delphian Corporation Method and apparatus for gas detector calibration

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4155712A (en) * 1976-04-12 1979-05-22 Taschek Walter G Miniature hydrogen generator
US4391682A (en) * 1980-02-11 1983-07-05 Kernforschungsanlage Julich Gmbh Method for electrolytic production of hydrogen
US4332664A (en) * 1980-09-09 1982-06-01 Csepel Muvek Hiradastechnikai Gepgyara Gas producing electrolytic cell for portable devices
US4489590A (en) * 1982-01-25 1984-12-25 Delphian Corporation Method and apparatus for gas detector calibration

Cited By (30)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2356708A (en) * 1999-11-27 2001-05-30 Central Research Lab Ltd Sensor system with self-test facility
US7159444B2 (en) 2002-11-26 2007-01-09 Proton Energy Systems, Inc. Combustible gas detection systems and method thereof
US7111493B2 (en) 2002-11-26 2006-09-26 Proton Energy Systems, Inc. Combustible gas detection system
US7073368B2 (en) 2004-05-28 2006-07-11 Honeywell International Inc. Calibration device for gas sensors
WO2005119248A1 (fr) * 2004-05-28 2005-12-15 Honeywell International Inc. Dispositif d'etalonnage pour systemes de controle de gaz
WO2006060320A2 (fr) * 2004-11-30 2006-06-08 Honeywell International Inc. Hydrures metalliques nano-crystallins et/ou metastables utilises comme source d'hydrogene a des fins d'etalonnage de capteurs et d'autodiagnostic
WO2006060320A3 (fr) * 2004-11-30 2006-08-17 Honeywell Int Inc Hydrures metalliques nano-crystallins et/ou metastables utilises comme source d'hydrogene a des fins d'etalonnage de capteurs et d'autodiagnostic
US7152458B2 (en) 2004-11-30 2006-12-26 Honeywell International Inc. Nano-crystalline and/or metastable metal hydrides as hydrogen source for sensor calibration and self-testing
WO2006063183A2 (fr) * 2004-12-08 2006-06-15 Honeywell International Inc. Systeme de detection electrochimique
WO2006063183A3 (fr) * 2004-12-08 2006-12-28 Honeywell Int Inc Systeme de detection electrochimique
US7174766B2 (en) 2005-05-24 2007-02-13 Honeywell International Inc. Calibration device for carbon dioxide sensor
US8826724B2 (en) 2010-12-24 2014-09-09 Honeywell International Inc. Carbon dioxide sensor
DE102015015152A1 (de) 2015-11-25 2017-06-01 Dräger Safety AG & Co. KGaA Verfahren zur Überprüfung eines Gassensors in einem Gasmesssystem
US9945827B2 (en) 2015-11-25 2018-04-17 Dräger Safety AG & Co. KGaA Method for testing a gas sensor in a gas-measuring system
EP3220141A1 (fr) 2016-03-18 2017-09-20 Dräger Safety AG & Co. KGaA Procédé de vérification d'un capteur de gaz et dispositif de mesure de gaz, détecteur de gaz comprenant un dispositif de vérification d'un capteur de gaz
US11209385B2 (en) 2016-03-18 2021-12-28 Dräger Safety AG & Co. KGaA Method for testing a gas sensor and gas-measuring device with a testing device for testing a gas sensor
DE102016003283A1 (de) 2016-03-18 2017-09-21 Dräger Safety AG & Co. KGaA Verfahren zur Überprüfung eines Gassensors und Gasmessvorrichtung mit einer Prüfvorrichtung zur Überprüfung eines Gassensors
US20170269026A1 (en) * 2016-03-18 2017-09-21 Dräger Safety AG & Co. KGaA Method for testing a gas sensor and gas-measuring device with a testing device for testing a gas sensor
EP3220142A1 (fr) 2016-03-18 2017-09-20 Dräger Safety AG & Co. KGaA Procédé de vérification d'un capteur de gaz et dispositif de mesure de gaz, détecteur de gaz comprenant un dispositif de vérification d'un capteur de gaz
DE102016003283B4 (de) 2016-03-18 2022-05-19 Dräger Safety AG & Co. KGaA Gasmessvorrichtung mit einer Prüfvorrichtung zur Überprüfung eines Gassensors
DE102016003284B4 (de) 2016-03-18 2022-05-19 Dräger Safety AG & Co. KGaA Gasmessvorrichtung mit einer Prüfvorrichtung zur Überprüfung eines Gassensors
DE102016003284A1 (de) 2016-03-18 2017-09-21 Dräger Safety AG & Co. KGaA Verfahren zur Überprüfung eines Gassensors und Gasmessvorrichtung mit einer Prüfvorrichtung zur Überprüfung eines Gassensors
US10132786B2 (en) 2016-03-18 2018-11-20 Dräger Safety AG & Co. KGaA Method for testing a gas sensor and gas-measuring device with a testing device for testing a gas sensor
DE102016013959A8 (de) 2016-11-23 2018-08-02 Drägerwerk AG & Co. KGaA Prüfvorrichtung zu einer Überprüfung eines Gasführungselementes
DE102016013959B4 (de) 2016-11-23 2019-08-08 Drägerwerk AG & Co. KGaA Prüfvorrichtung zu einer Überprüfung eines Gasführungselementes
US10648963B2 (en) 2016-11-23 2020-05-12 Drägerwerk AG & Co. KGaA Testing device for testing a gas guide element
US10712324B2 (en) 2016-11-23 2020-07-14 Drägerwerk AG & Co. KGaA Device with a pumping device for testing the operational capability of a gas guide element of a gas-measuring system
DE102016013958B4 (de) 2016-11-23 2019-08-08 Drägerwerk AG & Co. KGaA Vorrichtung mit einer Pumpeinrichtung zu einer Überprüfung einer Funktionsbereitschaft eines Gasführungselementes eines Gasmesssystems
DE102016013958A1 (de) 2016-11-23 2018-05-24 Drägerwerk AG & Co. KGaA Vorrichtung mit einer Pumpeinrichtung zu einer Überprüfung einer Funktionsbereitschaft eines Gasführungselementes eines Gasmesssystems
DE102016013959A1 (de) 2016-11-23 2018-05-24 Drägerwerk AG & Co. KGaA Prüfvorrichtung zu einer Überprüfung eines Gasführungselementes

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