EP0066472A1 - Détecteur de gaz explosible - Google Patents

Détecteur de gaz explosible Download PDF

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Publication number
EP0066472A1
EP0066472A1 EP82302797A EP82302797A EP0066472A1 EP 0066472 A1 EP0066472 A1 EP 0066472A1 EP 82302797 A EP82302797 A EP 82302797A EP 82302797 A EP82302797 A EP 82302797A EP 0066472 A1 EP0066472 A1 EP 0066472A1
Authority
EP
European Patent Office
Prior art keywords
lamp
detector
gas detector
gas
sensing head
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Withdrawn
Application number
EP82302797A
Other languages
German (de)
English (en)
Inventor
Keith Ian Lodewick
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
GAS MONITORING SYSTEMS (PTY) LIMITED
Original Assignee
GAS MONITORING SYSTEMS Pty Ltd
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 GAS MONITORING SYSTEMS Pty Ltd filed Critical GAS MONITORING SYSTEMS Pty Ltd
Publication of EP0066472A1 publication Critical patent/EP0066472A1/fr
Withdrawn legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B17/00—Fire alarms; Alarms responsive to explosion
    • G08B17/10—Actuation by presence of smoke or gases, e.g. automatic alarm devices for analysing flowing fluid materials by the use of optical means
    • G08B17/117—Actuation by presence of smoke or gases, e.g. automatic alarm devices for analysing flowing fluid materials by the use of optical means by using a detection device for specific gases, e.g. combustion products, produced by the fire
    • A—HUMAN NECESSITIES
    • A42—HEADWEAR
    • A42B—HATS; HEAD COVERINGS
    • A42B3/00—Helmets; Helmet covers ; Other protective head coverings
    • A42B3/04—Parts, details or accessories of helmets
    • A42B3/0406—Accessories for helmets
    • A42B3/0433—Detecting, signalling or lighting devices
    • A42B3/046—Means for detecting hazards or accidents

Definitions

  • This invention relates to a detector for explosive gases, particularly for detecting the presence of methane and/or carbon monoxide in underground mines.
  • This arrangement has the advantage that the detector is disposed relatively high on the miner's body, and no pump is needed to bring the atmosphere to the detector for testing. Since the chief dangerous gases are light and tend to collect at the top of the mine excavation, it is particularly suitable for the detector to be mounted at the level of the miner's head.
  • An object of the invention is to provide a miner's cap lamp arrangement in which these disadvantages are overcome or at least mitigated.
  • an electrically operated explosive gas detector for use in conjunction with a miner's cap lamp unit which includes a lamp housing, the detector being adapted to draw power from a battery of the unit and having a sensing head which obtains a sample of atmosphere to be sensed directly from the atmosphere surrounding the sensing head itself, characterised in that the sensing head and its associated heat-sensitive components are mounted in a casing separate from the lamp housing.
  • the casing for the sensing head and its associated heat-sensitive components may conveniently be fixed to the lamp housing directly or through brackets or the like which space this casing away from the lamp, or the casing may be mounted on a cable connecting the cap lamp to the battery.
  • the sensing head preferably works on the diffusion principle.
  • the invention also provides a miner's cap lamp unit including a battery and having an electrically operated gas detector connected to the battery of the unit and having a sensing head which obtains a sample of atmosphere to be sensed directly from the atmosphere surrounding the cap itself, the lamp having a switch wired together with the detector so that when the switch is turned on the lamp will only begin to operate correctly if the detector is in a working condition.
  • the circuitry may be arranged so that when the lamp is first switched on and the detector is in a working condition, the lamp light first comes on and then flickers for a short period to indicate that the detector is in an operative condition, before the light becomes steady. If the detector is not in a working condition, the light will not flicker.
  • the lamp when an explosive gas is detected the lamp preferably flickers so as to provide a clear indication of the presence of an explosive gas whilst still retaining sufficient illumination for the wearer to see his way away from the location of the gas.
  • the detector casing may be mounted on the side or the top of the cap lamp or as mentioned earlier, on the cable leading from the battery to the lamp and preferably near the lamp, between the lamp housing and a clip which is usually provided on the side of the cap to guide the cable away from the front of the cap.
  • the detector may be included in newly constructed cap lamps, or may be fitted to existing lamps.
  • Cap lamps are usually held on to the helmet by a releasable fastening, so that the lamp on the end of its cable can be removed.
  • This facility makes it possible to move the gas detector about to discover where the explosive gases are. For example, if the cable is long enough, the lamp with the detector can be raised at arm's length to see if there is a dangerous concentration of gases at the level of the hanging wall. Similarly, the lamp on the end of its lead could be lowered into a tank to test for explosive gases.
  • the positioning of the detector at head level is desirable because explosive gases in general and methane and carbon monoxide in particular are both lighter than air and will collect at the top of a mine excavation.
  • the sensing head is preferably of the gas-sensitive semi-conductor type and incorporates a stainless steel flashback arrestor and a sintered filter disc which may for example be of stainless steel, copper or brass.
  • the electronic circuitry can suitably be provided in microship form arranged to operate an electro-mechanical relay which switches the light on and off through an oscillator.
  • the circuitry and relay and other heat sensitive components are enclosed in the casing, which may be a moulded plastics body sealed by shock-resistant silicon rubber.
  • the lamp housing 1 fitted on a helmet 22 in Figure 1 can be of any suitable type, with an on/off switch 2 in a circuit between a battery 14 and a bulb 3.
  • the lamp housing 1 is connected to the battery 14 by means of a cable 4.
  • operation of the switch 2 causes the lamp to light.
  • a gas detector casing 5 is fixed to the top of the lamp housing 1.
  • the detector casing 5 contains a sensing head 6 mounted to one side of the casing 5, and it is this sensing head which picks up the presence of explosive gases.
  • the gas detector is connected into a circuit ( Figure 3) which includes the battery 14, the bulb 3 and the switch 2 by means of wiring which passes from the casing 5 directly into the lamp housing 1.
  • the sensing head 6 is a gas-sensitive semi-conductor sensor based on n-type sintered Sn02. When combustible or reducing gases are adsorbed on the sensor surface, a marked decrease of electrical resistance across the sensor occurs.
  • the electrical circuit of the sensor is shown in Figure 2, and this includes a heater coil 7 which raises the temperature of the sensor 8 above ambient temperature, to bring it into operation.
  • the two terminals attached to each side of the semi-conductor 8 are connected internally of the sensor unit, and the sensor unit is then connected into an electrical circuit by means of the connections 9 and 10, so that the circuit reacts to changes in the resistance of the semi-conductor 8 between the connections 9 and 10.
  • the sensing head 6 includes a stainless steel mesh flashback arrestor (not visible in the drawings), and a sintered filter disc 11 set in an aperture in the casing 5.
  • the electrical circuit associated with the sensing head is in microchip form and operates a normally closed electromechanical relay 16 the circuit includes an oscillator comparator 18 and is incorporated in the circuit supplying the bulb 3.
  • the function of the circuit is as follows:
  • the current through the resistor 20 is preferably about half the current required for a normal bright light condition where the relay 16 is closed. This arrangement reduces the surges in the circuit which can reduce the effective life of the battery. Such surges would become particularly detrimental if the light was switched completely off when the relay 16 opened.
  • the sensing head 6 can conveniently be of the type sold at the time of filing this application by Figaro Engineering Inc. of the United States of America under the designation TGG 812 or 813.
  • the electrical circuit can be a hybrid type in a microchip form which draws a maximum current of 110 mA which will be insufficient to have any noticeable effect on the power available from the battery.
  • the relay 16 can be a suitable electromechanical type working at an operational voltage of a minimum of 3,5 volts.
  • the detector casing 5 can be removed from the lamp housing 1.
  • the electrical cables 20 are shown broken but in practice suitable plugs and sockets are usually provided to facilitate electrically connecting the detector to the lamp. Detectors can thus be readily changed or replaced or added to a lamp casing as required.
  • the detector casing 5 is secured to the lamp housing 1 by two bolts 23 and 24.
  • a base plate 26 of the detector casing 5 is provided and is formed of a heat insulating material to reduce any transfer of heat from the lamp to the detector casing 5.
  • the sensing device decribed can sense methane, hydrogen, hydrogen sulphide and carbon monoxide, which are the main dangerous gases underground.
  • the sensing device can be adjusted to detect the following gas concentrations:
  • the detector described provides a continuous monitoring function of the atmosphere just above the miner's head, i.e. in the area where the highest concentration of explosive gases will build up. No pump is necessary to pass the gases over the detector, and thus a possible additonal source of battery drain is avoided.
  • the sensing head 6 may be physically separated from the circuitry in the casing 5, for instance by locating the sensing head 6 on the cable 4. If this is done, it will be advantageous to mount at the sensing head 6 near the point where the cable 4 enters the lamp housing 1, so that the sensing head will be at the highest point for reasons already given.
  • the invention extends to mounting of the sensing head and/or the electronic circuitry at any point along the length of the cord between the cap lamp and the battery 14, usually worn at the miner's waist.
  • the sensing head may be mounted apart from the cap lamp or its cord, provided that electricity for the sensing head and its associated circuitry is still drawn from the battery.
  • FIG. 6 illustrates an embodiment in which a gas detector casing 30 containing components similar to those described above with reference to the gas detector of Figures 1 to 5 is attached by means of metal brackets 32,34 and fixing bolts 36,38 to the top of a housing 40 of a miner's cap lamp.
  • the lamp is adapted to be removably attached to a miner's helmet by a clip 42 or other conventional means.
  • a short length of flexible cable 44 connects the circuitry of the gas detector in the casing 30 to the circuitry of the lamp, which is powered by a battery (not shown) at the end of a cable 46.
  • Glands 48,50 are provided to ensure the sealing of the cables 44 and 46 respectively where they enter the housing 40, and a similar gland (not visible) is provided on the gas detector casing 30 where the upper end of the cable 44 enters this casing.
  • the casing 30 has a window fitted with a sintered disc 52 which is a part of the sensing head of the detector.
  • a miner's helmet 60 is fitted with a cap lamp having a housing 62 that is powered by a battery (not shown) through a flexible cable 64.
  • a clip 66 on the helmet towards its rear holds the cable away from the miner's face.
  • a gas detector casing 68 is located in the cable 64 between the lamp housing 62 and the clip 66, and incorporates similar components to those described with reference to the earlier embodiments.
  • the sintered filter 70 forming part of the sensing device of the gas detector is in this version a band which extends around the periphery of the casing 68.
  • a portion 64A of the cable 64 between the gas detector casing 68 and the lamp housing 62 is modified to include the wires necessary to act upon the components of the lamp in the housing 62.
  • the gas detector's heat-sensitive components are located in a casing that is separate from the lamp housing, and thus the possibility of damaging these components or impairing their functioning by exposure to the heat generated in the lamp is eliminated or at least reduced to acceptable levels.
  • the invention allows a gas detector to be fitted to existing cap lamps with the minimum of structural changes to the cap lamp unit.
  • the lamp and the gas detector also remain independently accessible and replaceable in the invention in the event that either needs repair or fails entirely.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Business, Economics & Management (AREA)
  • Emergency Management (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Emergency Alarm Devices (AREA)
EP82302797A 1981-05-29 1982-06-01 Détecteur de gaz explosible Withdrawn EP0066472A1 (fr)

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
ZA813617 1981-05-29
ZA813617 1981-05-29
ZA816116 1981-09-03
ZA816116 1981-09-03
ZA82785 1982-02-08
ZA820785 1982-02-08

Publications (1)

Publication Number Publication Date
EP0066472A1 true EP0066472A1 (fr) 1982-12-08

Family

ID=27420909

Family Applications (1)

Application Number Title Priority Date Filing Date
EP82302797A Withdrawn EP0066472A1 (fr) 1981-05-29 1982-06-01 Détecteur de gaz explosible

Country Status (2)

Country Link
EP (1) EP0066472A1 (fr)
AU (1) AU8433982A (fr)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2016845A2 (fr) * 2007-07-20 2009-01-21 Koehler-Bright Star Inc. Adaptateur de module électronique pour casque
GB2459944A (en) * 2008-05-15 2009-11-18 Draeger Safety Ag & Co Kgaa Article of safety wear with gas alarm indicator
CN102062301A (zh) * 2010-10-13 2011-05-18 彭映斌 节能型多功能一体化矿灯
CN107290385A (zh) * 2017-06-09 2017-10-24 公安部上海消防研究所 头盔耐燃烧性能测试装置及其测试方法
US9885471B2 (en) 2007-07-20 2018-02-06 Koehler-Bright Star LLC Multiple electronic tag holder
CN108703430A (zh) * 2018-05-15 2018-10-26 安徽天卓信息技术有限公司 一种矿用气体检测安全帽及其检测方法
CN116293544A (zh) * 2023-05-10 2023-06-23 江苏恒械机械有限公司 一种矿洞用易携带式照明器具

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113796616B (zh) * 2021-10-26 2023-08-04 西安科技大学 一种煤矿安全管理用安全装备佩戴警示装置及其警示方法

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1506941A (fr) * 1966-12-29 1967-12-22 Inst Gornogo Dela Imeni Skochi Analyseur de gaz thermochimique portatif
EP0016351A1 (fr) * 1979-03-16 1980-10-01 Cerberus Ag Détecteur de gaz à utiliser dans un milieu menacé par des explosions
US4263588A (en) * 1979-07-25 1981-04-21 Oldham France S.A. Helmet-carried apparatus for detecting and signalling the presence of a dangerous gas in an atmosphere

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1506941A (fr) * 1966-12-29 1967-12-22 Inst Gornogo Dela Imeni Skochi Analyseur de gaz thermochimique portatif
EP0016351A1 (fr) * 1979-03-16 1980-10-01 Cerberus Ag Détecteur de gaz à utiliser dans un milieu menacé par des explosions
US4263588A (en) * 1979-07-25 1981-04-21 Oldham France S.A. Helmet-carried apparatus for detecting and signalling the presence of a dangerous gas in an atmosphere

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2016845A2 (fr) * 2007-07-20 2009-01-21 Koehler-Bright Star Inc. Adaptateur de module électronique pour casque
EP2016845A3 (fr) * 2007-07-20 2010-03-10 Koehler-Bright Star Inc. Adaptateur de module électronique pour casque
AU2008203236B2 (en) * 2007-07-20 2013-05-23 Koehler-Bright Star, Inc. Eletronic module adapter for headgear
US9885471B2 (en) 2007-07-20 2018-02-06 Koehler-Bright Star LLC Multiple electronic tag holder
GB2459944A (en) * 2008-05-15 2009-11-18 Draeger Safety Ag & Co Kgaa Article of safety wear with gas alarm indicator
US8103459B2 (en) 2008-05-15 2012-01-24 Dräger Safety AG & Co. KGaA Safety clothing
CN102062301A (zh) * 2010-10-13 2011-05-18 彭映斌 节能型多功能一体化矿灯
CN107290385A (zh) * 2017-06-09 2017-10-24 公安部上海消防研究所 头盔耐燃烧性能测试装置及其测试方法
CN108703430A (zh) * 2018-05-15 2018-10-26 安徽天卓信息技术有限公司 一种矿用气体检测安全帽及其检测方法
CN116293544A (zh) * 2023-05-10 2023-06-23 江苏恒械机械有限公司 一种矿洞用易携带式照明器具

Also Published As

Publication number Publication date
AU8433982A (en) 1982-12-02

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Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Designated state(s): AT BE CH DE FR GB IT LU NL SE

ITCL It: translation for ep claims filed

Representative=s name: JACOBACCI CASETTA & PERANI S.P.A.

17P Request for examination filed

Effective date: 19830603

RAP1 Party data changed (applicant data changed or rights of an application transferred)

Owner name: GAS MONITORING SYSTEMS (PTY) LIMITED

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 19850730

RIN1 Information on inventor provided before grant (corrected)

Inventor name: LODEWICK, KEITH IAN