GB2054156A - Apparatus for Detecting and Signalling the Presence of a Dangerous Gas in an Atmosphere - Google Patents
Apparatus for Detecting and Signalling the Presence of a Dangerous Gas in an Atmosphere Download PDFInfo
- Publication number
- GB2054156A GB2054156A GB7924956A GB7924956A GB2054156A GB 2054156 A GB2054156 A GB 2054156A GB 7924956 A GB7924956 A GB 7924956A GB 7924956 A GB7924956 A GB 7924956A GB 2054156 A GB2054156 A GB 2054156A
- Authority
- GB
- United Kingdom
- Prior art keywords
- detecting
- signalling
- gas
- atmosphere
- lamp
- 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.)
- Granted
Links
- 230000011664 signaling Effects 0.000 title claims abstract description 25
- 230000000977 initiatory effect Effects 0.000 claims description 4
- 230000003197 catalytic effect Effects 0.000 claims 1
- 230000035945 sensitivity Effects 0.000 abstract description 3
- 238000010276 construction Methods 0.000 abstract description 2
- 239000007789 gas Substances 0.000 description 13
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 4
- 230000001276 controlling effect Effects 0.000 description 2
- 238000005286 illumination Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 230000001105 regulatory effect Effects 0.000 description 2
- 210000000988 bone and bone Anatomy 0.000 description 1
- OJIJEKBXJYRIBZ-UHFFFAOYSA-N cadmium nickel Chemical compound [Ni].[Cd] OJIJEKBXJYRIBZ-UHFFFAOYSA-N 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- ZTMKADLOSYKWCA-UHFFFAOYSA-N lenacil Chemical compound O=C1NC=2CCCC=2C(=O)N1C1CCCCC1 ZTMKADLOSYKWCA-UHFFFAOYSA-N 0.000 description 1
- 210000001595 mastoid Anatomy 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000009877 rendering Methods 0.000 description 1
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
-
- 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
-
- 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
- G01N33/0062—General constructional details of gas analysers, e.g. portable test equipment concerning the measuring method or the display, e.g. intermittent measurement or digital display
- G01N33/0063—General constructional details of gas analysers, e.g. portable test equipment concerning the measuring method or the display, e.g. intermittent measurement or digital display using a threshold to release an alarm or displaying means
Landscapes
- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Analytical Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Engineering & Computer Science (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- Pathology (AREA)
- Combustion & Propulsion (AREA)
- Business, Economics & Management (AREA)
- Medicinal Chemistry (AREA)
- Food Science & Technology (AREA)
- Emergency Management (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Emergency Alarm Devices (AREA)
Abstract
Apparatus for detecting and signalling the presence of a dangerous gas in an atmosphere comprising means (1,8,9,10) for detecting the gas and means (6,7) for signalling when the gas content exceeds a predetermined level. Said detecting means and said signalling means are disposed in a common housing and connected by a double-wire cable to a separate supply (2). The apparatus is easy to use, is of simple and light construction and is therefore particularly suitable to form part of a miner's helmet lamp assembly. In such an arrangement the signalling means (7) may comprise the helmet lamp itself, power to the lamp being intermittently interrupted by a multivibrator in the means (6). The sensitivity of the apparatus conforms to European safety standards. <IMAGE>
Description
SPECIFICATION
Apparatus for Detecting and Signalling the
Presence of a Dangerous Gas in an
Atmosphere
The present invention relates to apparatus for detecting the presence of dangerous gases in mine galleries and for signalling the danger of such a gas when the concentration thereof in the atmosphere of a mine reaches a predetermined level.
Many detecting and signalling devices are known among which may be mentioned bridge detectors whose sensitivity corresponds to safety standards which are set for the mines of countries of Western Europe.
An object of the invention is to provide a measuring and signalling apparatus, which is sometimes termed a "firedampscope" lamp which, while it has a performance which satisfies the existing standards, is particularly easy to use and relatively simple in construction and permits rendering the equipment of the miner lighter.
According to the invention, there is provided an apparatus for detecting and signalling the presence of a dangerous gas in an atmosphere, comprising means for detecting said gas and means for signalling when the content of the gas exceeds a predetermined level, wherein said detecting means and said signalling means are disposed in a common housing and are connected by a double-wire cable to a separate supply.
Further features of the invention will be apparent from the ensuing description.
In the accompanying drawings, which are given solely by way of example:
Fig. 1 is an electric diagram of the detecting and signalling apparatus according to the invention;
Fig. 2 is a perspective view of a helmet in which the apparatus of the invention is incorporated;
Fig. 3 is a view of another embodiment of the apparatus according to the invention.
The circuit shown in Fig. 1 comprises a detecting and initiating unit 1, defined by a rectangle in dot-dash lines and supplied with power by a DC supply 2 constituted, for example, by a lead accumulator battery or a cadmiumnickel battery through a voltage regulating circuit 3.
The regulating circuit 3 is connected to the battery 2 through a switch 4 having three contact positions.
A dim lamp 5 is connected to one of said contact positions of the switch.
Connected to the output of the detecting and initiating unit 1, is a circuit 6 for controlling the flashing of a lamp 7, this lamp also performing the function of an illuminating lamp.
The detecting and initiating circuit 1 comprises a Wheatstone bridge 8 whose branches 9 and 10 are constituted by a detector filament Fd and a compensating filament Fc. The other two branches 11 and 1 2 of the bridge 8 each comprise a resistor X, Y and a part of a potentiometer P whose slide constitutes the terminal of the diagonal of the bridge. Also connected in the branch 12 is a resistor 1 3 which is in series with the resistor Y and has a value R=X-Y.
Connected in the diagonal part of the bridge 8 by its two inputs is an operational amplifier 14 whose output constitutes the output of the circuit 1 and is connected to the input of the control circuit 6.
The resistor 1 3 is moreover part of a voltagedivider which also comprises a resistor 1 5 which is connected between the output of the amplifier 14 and the junction point of the resistors 12 and 13.
The flash controlling circuit 6 is an astable multivibrator circuit which is adapted to intermittently cut off the supply current of the illuminating lamp 7.
Thus it can be seen that the device, whose electric circuit is shown in Fig. 1 and whose operation will be described in detail hereinafter, performs the double function of a normal illumination and the signalling of an excess of gas in the surrounding atmosphere.
The Applicant has incorporated this device in one and the same unit.
In Fig. 2, there is shown a helmet 16 which comprises, above its vizor 17, a housing 1 8 which is moulded therewith.
In its inner part, the housing 18 is provided with a window 1 9 through which can be seen the illuminating lamp 17 and the dim lamp 5 of the circuit of Fig. 1.
According to a particular feature of the invention, the whole of the circuit of Fig. 1, apart from the battery 2, is disposed in the housing 18 which has a sealed region containing the lamps 5 and 7 and a region for receiving the gas which contains the filaments 9 and 10 of the detector.
The gas-receiving region is put in communication with the exterior by way of passageways 2û of sintered metal.
The circuit contained in the housing 1 8 is supplied with current by the battery (not shown) through a double-wire cable 21.
The double-wire connection between the battery and the helmet containing the detecting and signalling circuit is an important feature of the invention.
The apparatus shown in Fig. 3 comprises all of the elements of the circuit of Fig. 1 but, instead of being incorporated in a helmet, it is disposed in a separate housing 22 which is provided in the front part with a sealed compartment 23 in which the dim lamp 5 and illuminating lamp 7 are disposed and a compartment 24 which communicates with the surrounding atmosphere by way of passageways 25 and contains the whole of the electronic circuit.
The housing has a system 26 for securing it to a helmet or other means.
The apparatus of Fig. 3 in fact has the appearance of a conventional miner's lamp, but the detecting and signalling means essential to the work carried out in a firedamp atmosphere are associated with this lamp.
The operation of the device shown in Fig. 1 will now be described.
When the switch 4 is placed in its lower contact position shown in Fig. 1 , the dim lamp 5 is the sole element of the device which is connected to the battery 2. It therefore supplies a light of low intensity and the rest of the device is inoperative.
When the switch 4 is placed in its upper contact position the whole of the device is put in circuit and the supply of the lamp 5 is cut off.
In a normal atmosphere, the lamp 7 is directly supplied with current by the battery 2 and provides a normal continuous illumination.
As concerns the detecting bridge 1 which is supplied with current by the voltage regulator 3, it constantly measures the content of, for example, methane in the surrounding atmosphere.
The resistors 13, 12, 11 and the potentiometer
P form a voltage divider which is connected between the terminals of the regulator 3.
The potentiometer P consequently permits a modification of the value of the reference voltage of the divider and consequently the threshold of actuation of the device, that is to say its sensitivity to the content of gas in the surrounding atmosphere.
The filaments 9 and 10 are in contact with the atmosphere containing the gas to be detected, but only the filament 9 heats in the presence of the gas.
The filament 10 has for sole purpose to compensate for variations in the surrounding humidity, pressure and temperature.
In the absence of gas, the potential at the terminals of the filament 10 is equal to that across the terminals of the filament 9.
The + input potential of the amplifier 14 is higher than the potential at its - input.
When the filament 9 heats in the presence of gas, its resistance increases and the voltage at the input of the amplifier 14 increases.
The output potential of the amplifier 14 remains positive until the potential at its - input becomes higher than the potential at its + input.
Then the output potential of the amplifier 14 becomes negative and introduces in the resistor 1 3 of value R a voltage drop which is a function of
R and of the value K of the resistor 1 5.
This modification results in a drop in the potential at the + input of the amplifier 14 which actuates the multivibrator 6.
The latter produces the flashing of the lamp 7.
The flash frequency is such that it does not hinder the bearer of the lamp owing to the short duration of the non-illuminating period.
Tests carried out have shown that the apparatus according to the invention has a precision higher than +0.1 G of CH4.
The supply battery 2 of the apparatus, which battery is placed on the belt of the user, may be advantageously a battery of the "T" type (Oldham 13 Ah) which has a life similar to that of conventional miner hat lamps.
In the embodiments just described, the signalling is effected by a flashing of a lamp.
However, it will be understood that this signalling may be effected by any other means such as a transmitter of vibrations via the bone structure which is placed on the helmet in the region of the mastoid bone of the user.
Claims (9)
1. An apparatus for detecting and signalling the presence of a dangerous gas in an atmosphere, comprising means for detecting said gas and means for signalling when the content of the gas exceeds a predetermined level which are disposed in a common housing and connected to a separate supply, wherein said common housing is a housing of a helmet lamp and said detecting means and said signalling means are connected to said separate supply by way of a double-wire cable.
2. An apparatus as claimed in claim 1, wherein said signalling means comprise a lamp which is part of a portable illuminating equipment contained in said housing, and flash-producing means interrupting the supply current of said lamp at a predetermined rate in response to an initiating signal delivered by said detecting means.
3. An apparatus as claimed in claim 2, wherein said detecting means comprise a measuring bridge having at least one branch which comprises a catalytic detecting filament for detecting the presence of said gas, said measuring bridge being supplied with current by said supply through a voltage regulator and comprising a comparator having two inputs which are connected to a terminal of a diagonal portion of the measuring bridge, the output of said comparator being connected to the input of the flash-producing means.
4. An apparatus as claimed in claim 2 or 3, wherein said flash-producing means comprise a multivibrator circuit.
5. An apparatus as claimed in any one of the claims 1 to 4, wherein said housing of a helmet lamp comprises a compartment which is sealed from the gas and contains at least said illuminating lamp and a compartment which communicates with the atmosphere by way of passageways and contains at least said detecting means.
6. An apparatus as claimed in claim 5, wherein said housing is an integral part of a helmet.
7. An apparatus for detecting and signalling the presence of a dangerous gas in an atmosphere, substantially as hereinbefore described with reference to and as shown in Fig. 1 of the accompanying drawings.
8. An apparatus for detecting and signalling the presence of a dangerous gas in an atmosphere, substantially as hereinbefore described with reference to and as shown in Fig. 2 of the accompanying drawings.
9. An apparatus for detecting and signalling the presence of a dangerous gas in an atmosphere, substantially as hereinbefore described with reference to and as shown in Fig. 3 of the accompanying drawings.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB7924956A GB2054156B (en) | 1979-07-18 | 1979-07-18 | Apparatus for detecting and signalling the presence of a dangerous gas in an atmosphere |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB7924956A GB2054156B (en) | 1979-07-18 | 1979-07-18 | Apparatus for detecting and signalling the presence of a dangerous gas in an atmosphere |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2054156A true GB2054156A (en) | 1981-02-11 |
| GB2054156B GB2054156B (en) | 1984-02-29 |
Family
ID=10506568
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB7924956A Expired GB2054156B (en) | 1979-07-18 | 1979-07-18 | Apparatus for detecting and signalling the presence of a dangerous gas in an atmosphere |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2054156B (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0291438A2 (en) * | 1987-05-11 | 1988-11-17 | Suministros Adaro, S.A. | Portable safety unit for miners |
| EP2000737A1 (en) * | 2007-05-29 | 2008-12-10 | Koehler-Bright Star, Inc. | Module adapter for portable light sources |
| GB2459944A (en) * | 2008-05-15 | 2009-11-18 | Draeger Safety Ag & Co Kgaa | Article of safety wear with gas alarm indicator |
-
1979
- 1979-07-18 GB GB7924956A patent/GB2054156B/en not_active Expired
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0291438A2 (en) * | 1987-05-11 | 1988-11-17 | Suministros Adaro, S.A. | Portable safety unit for miners |
| EP0291438A3 (en) * | 1987-05-11 | 1989-10-18 | Suministros Adaro, S.A. | Portable safety unit for miners |
| EP2000737A1 (en) * | 2007-05-29 | 2008-12-10 | Koehler-Bright Star, Inc. | Module adapter for portable light sources |
| AU2008202285B2 (en) * | 2007-05-29 | 2013-03-28 | Koehler-Bright Star, Inc. | Module adapter for portable light sources |
| 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 |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2054156B (en) | 1984-02-29 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PE20 | Patent expired after termination of 20 years |
Effective date: 19990717 |