CA1124361A - Fire or explosion detection - Google Patents
Fire or explosion detectionInfo
- Publication number
- CA1124361A CA1124361A CA377,355A CA377355A CA1124361A CA 1124361 A CA1124361 A CA 1124361A CA 377355 A CA377355 A CA 377355A CA 1124361 A CA1124361 A CA 1124361A
- Authority
- CA
- Canada
- Prior art keywords
- radiation
- output
- electrical
- fire
- produce
- 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.)
- Expired
Links
- 238000004880 explosion Methods 0.000 title claims abstract description 24
- 238000001514 detection method Methods 0.000 title claims abstract description 5
- 230000005855 radiation Effects 0.000 claims abstract description 42
- 230000001419 dependent effect Effects 0.000 claims description 6
- 230000003111 delayed effect Effects 0.000 claims description 3
- 238000007493 shaping process Methods 0.000 claims description 2
- 230000004044 response Effects 0.000 abstract description 5
- 230000001629 suppression Effects 0.000 description 3
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 230000000977 initiatory effect Effects 0.000 description 1
- 230000006335 response to radiation Effects 0.000 description 1
- GGYFMLJDMAMTAB-UHFFFAOYSA-N selanylidenelead Chemical compound [Pb]=[Se] GGYFMLJDMAMTAB-UHFFFAOYSA-N 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 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
- G08B17/12—Actuation by presence of radiation or particles, e.g. of infrared radiation or of ions
Landscapes
- Business, Economics & Management (AREA)
- Emergency Management (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Fire-Detection Mechanisms (AREA)
- Photometry And Measurement Of Optical Pulse Characteristics (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A fire or explosion detection system comprises a photo-electric type detector responsive to radiation in a narrow wavelength band characteristic of the fires or explosions, and a slow-response detector, such as a thermopile, sensitive to radiation in a different narrow wavelength band centred at, for example, 4.4 microns, again characteristic of the fires or explosions. The electrical outputs of the detectors are fed into a ratio unit which causes an AND gate to produce a fire or explosion indicating output only when the ratio of the output of the thermopile detector to the output of the other detector exceeds a predetermined value.
A fire or explosion detection system comprises a photo-electric type detector responsive to radiation in a narrow wavelength band characteristic of the fires or explosions, and a slow-response detector, such as a thermopile, sensitive to radiation in a different narrow wavelength band centred at, for example, 4.4 microns, again characteristic of the fires or explosions. The electrical outputs of the detectors are fed into a ratio unit which causes an AND gate to produce a fire or explosion indicating output only when the ratio of the output of the thermopile detector to the output of the other detector exceeds a predetermined value.
Description
2~3~1 BACKGROUND Ol~ T~i~ INVENTION
The invention relates to fire and explosion detection systems.
lire and explosion detection systems are ~nown which respond to radiation which is produced by such an event.
Specifically, systems are known which use radiation detectors producing an electrical output in dependence on the intensity of the radiation sensed. It is also known to arrange, in such systems, for the radiation detector to be sensitive to radiation in a wavelength band characteristic of the particular type of fire or explosion to be detected. In this way, it is intended that there will be better discrimination against extraneous "noise", that is, other sources or radiation.
;~ An object of the invention is to provide an improved system for detecting fires or explosions. A more specific object is to provide such a system which does not depend on the output of a single detector reaching a predetermined value. A further object of the invention is to provide such a system which gives better discrimiantion against constant high-colour-temperature noise sources.
BRIEF S~ ~ARY OF THE I~VE_TION
According to the invention, there is provided a system for detecting fires or explosions emitting radiation having .
~ . :
.2~
a characteristic wavelength and also emitting radiation at o~her wavelengtlls, comprising first radiation sensing means arranged to sense radiation in a narrow wavelength band includillg tlle cllaracteristic wavelength and to produce a first elcctrical output dependent on the intensity of the radiation sensed but delayed with respect thereto, second radiation sensing means arranged to sense radiation in a wavelength band including one of the other said wavelengths and producing a second electrical output relatively instan-taneously dependent on the intensity of the radiation sensed, means for measuring the ratio of the two electrical outputs, and output means ~or~producing a fire or explosion indicating output only when the ratio of the first electrical output to the second electrical output exceeds a predeterminedvalue.
BRI~F LSCRIPTION OF THE DRAWINGS
Fire and explosion systems embodying the invention will now be described, by way of example, with reference to the accompanying diagrammatic drawings in which:
Figure 1 is a block circuit diagram of one of the system; and Figure 2 is a graph showing waveforms occurring in the syster.l.
' '': ' ' ~
~Z~
DESCRIPTION OF PREFERI~D EMBODIMENTS
~ s shown in ligure 1, one ~orm of the system eom-prises two radiation detectors 10 and 12 each of which produces an electrieal output in response to radiation receivecl, Detector 10 is made to produce an output characteristie of radiation in a narrow wavelength band lying in the range '' 0.7 to 1.2 mierons, e.g.O.96 mierons. For example, the detector 10 may be a photo-eleetric type detector such as a silicon diode det~ector arranged to view radiation through a filter transmitting radiation only within the required wavelength band.
The detector 12 is arranged to be sensitive to radiation in a narrow wavelength band eentred at 4.4 microns. Speeifieally, deteetor 12 is of a type arranged to produee a delayed output. ~or example, the deteetor ~, 12 may be a thermopile-type sensor arranged to reeeive radiation through a filter having the required wavelength transmitting band and thus produeing a delayecl output ~eeause of the thermal inertia of the thennopile. Instead, however, tlle deteetor 12 eould be in tlle form o~ a photo-electrie type deteetor, sueh as a lead selenide deteetor, agaitl arrall~e~ to reeeive racdiation througll a ~ilter having the required wavelenp~th transmittinp, band, and ~eeding its output throu~h a signal sha~in~ circui.t~
:
~ , .
,,~, ~ .. . ... .. . . . .
, ., ~ - . .
, `
` ' ~
. .
~ : , 2~3~1 Detector 10 feeds its output through an amplifier 14A to one input of a ratio unit 16, and also to a comparator 18A. The comparator 18A compares the magnitude of the amplifier output with a predetermined threshold value produced by a reference signal on a line 20A and changes its output from binary "0" to binary "1" when the amplifier output exceeds the threshold, and the binary output is fed to one input of an AND gate 22.
Detector 12 feeds its output through an amplifier 14B to the second input of the ratio unit 16 and also to a comparator 18B corresponding to comparator 18A.
Comparator 18B receives a reference on a line 20B, representing a predetermined threshold, and again the output of comparator 18B changes from binary "0" to binary "1" when the amplifier output exceeds the threshold ~ represented by the signal on line 20B, and the binary ............. output is fed to a second input of AND gate 22.
The third input of AND gate 22 is fed by the ratio unit 16. The ratio unit 16 is arranged to produce a binary "0" when the amplified output of detector lO
exceeds the amplified output of detector 12, and to switch to binary "1" when the reverse conditions apply.
In Figure 2, curve A represents the electrical output of detector 10 in response to a fire or ex~losion, and curve B represents the electrical output of detector 12 in response to that fire or explosion. In this case, . ,' `.
--" ~ 5 ~ Z4~
the fire or explosion is assumed to be one producing C02, the characteristic wavelength relating to which is ~.4 microns.
The fire or explosion is assumed to start at time to.
Because of the thermal inertia of the thermopile sensor in detector 12 (or because of the signal shaping circuit in the alternative form suggested above for this detector), curve B rises comparatively slowly in response to the fire or explosion, while curve A rises substantially isntantaneously.
The threshold levels applied by the comparators 13A
and 18B are shown at I in ~igure 2.
After time tl, both comparators 18A and 18B will be producing "l" outputs. ilowever, as long as the output of amylifier 14B is less than the output of amplifier 14A, the ratio unit 16 will produce a "0" output, and there- -fore AND gate 22 will produce a "0" ou~put.
At time t2, however, the output of ratio unit 16 will change to "l", and A~D gate 2Z will now SWitcil to produce a "l" output which indicates thepresence of the ~; fire or explosion and can be used to initiate suppression actionO
The foregoing applies particularly tothe case where ~: the event occurring is an explosion (e O g ~ an exploding high energy anti-tank (or H~EoA~To) round striking a battle tank or armoured personnel-carrying vehicle) which subse-quently starts a fireO In this case, therefore, the , .
, .
- . , :~ :
~3~2~
actual fire may not start until after fire suppression has been initiated (at time t2)o However, if the fire is not a fire started in this way by an explosion but is itself the initiating event, then it will be detected in the same way (when the output of the ratio unit 16 switches to "l") but the system is then responding to the actual fire and not "predicting" the fireO However, such a fire (eOgOcaused by a leakage of hydraulic fluid in a vehicle) is itself a slower growing fire, and therefore the need for prediction is lessenedO
The use of a detector operating at 404 microns is advantageous because it prevents the system responding to an extraneous noise such as solar radiation or conventional lightingO The addition of the 0096 micron detector 10 is advantageous because it ensures that the system initiates warning or suppression action in response to the cor,lparison of the outputs of two detectors and does not depend, for example, on the output of a single detector reaching a predetermined value~ In addition, there is better discrimination against constant high colour temperature noise sourcesO If the threshold levels in both channels are sufficiently high,discrimination can also be provi.ded against infra-red noise sources, such as electric bar heaters or lasersO
.
i . . , , - ,~. ~
The invention relates to fire and explosion detection systems.
lire and explosion detection systems are ~nown which respond to radiation which is produced by such an event.
Specifically, systems are known which use radiation detectors producing an electrical output in dependence on the intensity of the radiation sensed. It is also known to arrange, in such systems, for the radiation detector to be sensitive to radiation in a wavelength band characteristic of the particular type of fire or explosion to be detected. In this way, it is intended that there will be better discrimination against extraneous "noise", that is, other sources or radiation.
;~ An object of the invention is to provide an improved system for detecting fires or explosions. A more specific object is to provide such a system which does not depend on the output of a single detector reaching a predetermined value. A further object of the invention is to provide such a system which gives better discrimiantion against constant high-colour-temperature noise sources.
BRIEF S~ ~ARY OF THE I~VE_TION
According to the invention, there is provided a system for detecting fires or explosions emitting radiation having .
~ . :
.2~
a characteristic wavelength and also emitting radiation at o~her wavelengtlls, comprising first radiation sensing means arranged to sense radiation in a narrow wavelength band includillg tlle cllaracteristic wavelength and to produce a first elcctrical output dependent on the intensity of the radiation sensed but delayed with respect thereto, second radiation sensing means arranged to sense radiation in a wavelength band including one of the other said wavelengths and producing a second electrical output relatively instan-taneously dependent on the intensity of the radiation sensed, means for measuring the ratio of the two electrical outputs, and output means ~or~producing a fire or explosion indicating output only when the ratio of the first electrical output to the second electrical output exceeds a predeterminedvalue.
BRI~F LSCRIPTION OF THE DRAWINGS
Fire and explosion systems embodying the invention will now be described, by way of example, with reference to the accompanying diagrammatic drawings in which:
Figure 1 is a block circuit diagram of one of the system; and Figure 2 is a graph showing waveforms occurring in the syster.l.
' '': ' ' ~
~Z~
DESCRIPTION OF PREFERI~D EMBODIMENTS
~ s shown in ligure 1, one ~orm of the system eom-prises two radiation detectors 10 and 12 each of which produces an electrieal output in response to radiation receivecl, Detector 10 is made to produce an output characteristie of radiation in a narrow wavelength band lying in the range '' 0.7 to 1.2 mierons, e.g.O.96 mierons. For example, the detector 10 may be a photo-eleetric type detector such as a silicon diode det~ector arranged to view radiation through a filter transmitting radiation only within the required wavelength band.
The detector 12 is arranged to be sensitive to radiation in a narrow wavelength band eentred at 4.4 microns. Speeifieally, deteetor 12 is of a type arranged to produee a delayed output. ~or example, the deteetor ~, 12 may be a thermopile-type sensor arranged to reeeive radiation through a filter having the required wavelength transmitting band and thus produeing a delayecl output ~eeause of the thermal inertia of the thennopile. Instead, however, tlle deteetor 12 eould be in tlle form o~ a photo-electrie type deteetor, sueh as a lead selenide deteetor, agaitl arrall~e~ to reeeive racdiation througll a ~ilter having the required wavelenp~th transmittinp, band, and ~eeding its output throu~h a signal sha~in~ circui.t~
:
~ , .
,,~, ~ .. . ... .. . . . .
, ., ~ - . .
, `
` ' ~
. .
~ : , 2~3~1 Detector 10 feeds its output through an amplifier 14A to one input of a ratio unit 16, and also to a comparator 18A. The comparator 18A compares the magnitude of the amplifier output with a predetermined threshold value produced by a reference signal on a line 20A and changes its output from binary "0" to binary "1" when the amplifier output exceeds the threshold, and the binary output is fed to one input of an AND gate 22.
Detector 12 feeds its output through an amplifier 14B to the second input of the ratio unit 16 and also to a comparator 18B corresponding to comparator 18A.
Comparator 18B receives a reference on a line 20B, representing a predetermined threshold, and again the output of comparator 18B changes from binary "0" to binary "1" when the amplifier output exceeds the threshold ~ represented by the signal on line 20B, and the binary ............. output is fed to a second input of AND gate 22.
The third input of AND gate 22 is fed by the ratio unit 16. The ratio unit 16 is arranged to produce a binary "0" when the amplified output of detector lO
exceeds the amplified output of detector 12, and to switch to binary "1" when the reverse conditions apply.
In Figure 2, curve A represents the electrical output of detector 10 in response to a fire or ex~losion, and curve B represents the electrical output of detector 12 in response to that fire or explosion. In this case, . ,' `.
--" ~ 5 ~ Z4~
the fire or explosion is assumed to be one producing C02, the characteristic wavelength relating to which is ~.4 microns.
The fire or explosion is assumed to start at time to.
Because of the thermal inertia of the thermopile sensor in detector 12 (or because of the signal shaping circuit in the alternative form suggested above for this detector), curve B rises comparatively slowly in response to the fire or explosion, while curve A rises substantially isntantaneously.
The threshold levels applied by the comparators 13A
and 18B are shown at I in ~igure 2.
After time tl, both comparators 18A and 18B will be producing "l" outputs. ilowever, as long as the output of amylifier 14B is less than the output of amplifier 14A, the ratio unit 16 will produce a "0" output, and there- -fore AND gate 22 will produce a "0" ou~put.
At time t2, however, the output of ratio unit 16 will change to "l", and A~D gate 2Z will now SWitcil to produce a "l" output which indicates thepresence of the ~; fire or explosion and can be used to initiate suppression actionO
The foregoing applies particularly tothe case where ~: the event occurring is an explosion (e O g ~ an exploding high energy anti-tank (or H~EoA~To) round striking a battle tank or armoured personnel-carrying vehicle) which subse-quently starts a fireO In this case, therefore, the , .
, .
- . , :~ :
~3~2~
actual fire may not start until after fire suppression has been initiated (at time t2)o However, if the fire is not a fire started in this way by an explosion but is itself the initiating event, then it will be detected in the same way (when the output of the ratio unit 16 switches to "l") but the system is then responding to the actual fire and not "predicting" the fireO However, such a fire (eOgOcaused by a leakage of hydraulic fluid in a vehicle) is itself a slower growing fire, and therefore the need for prediction is lessenedO
The use of a detector operating at 404 microns is advantageous because it prevents the system responding to an extraneous noise such as solar radiation or conventional lightingO The addition of the 0096 micron detector 10 is advantageous because it ensures that the system initiates warning or suppression action in response to the cor,lparison of the outputs of two detectors and does not depend, for example, on the output of a single detector reaching a predetermined value~ In addition, there is better discrimination against constant high colour temperature noise sourcesO If the threshold levels in both channels are sufficiently high,discrimination can also be provi.ded against infra-red noise sources, such as electric bar heaters or lasersO
.
i . . , , - ,~. ~
Claims (6)
1. A system for detecting fires or explosions emitting radiation having a characteristic wavelength and also emitting radiation at other wavelengths, comprising first radiation sensing means to sense radiation in a narrow wavelength band including the characteristic wavelength and to produce a first electrical output dependent on the intensity of the radiation sensed but delayed with respect thereto, second radiation sensing means to sense radiation in a wavelength band including one of the other said wave-lengths and producing a second electrical output relatively instantaneously dependent on the intensity of the radiation sensed, means measuring the ratio of the two electrical outputs, and output means producing a fire or explosion indicating output only when the ratio of the first electrical output to the second electrical output exceeds a predetermined value.
2. A system according to claim 1, including means responsive to at least one of the first and second electrical outputs to determine when the value of that output exceeds a predetermined threshold and to prevent the production of the said fire or explosion indicating output until the said threshold is exceeded.
3. A system according to claim 1, in which the first radiation sensing means comprises a thermopile sensor, and a filter having a narrow passband including the said charac-teristic wavelength, the thermopile sensor receiving the said radiation through the filter.
4. A system according to claim 1, in which the first radiation detection means comprises a photo-electric type sensor, a filter having a narrow passband including the said characteristic wavelength and through which the photo-electric type sensor receives the said radiation, and a signal shaping circuit responsive to the output of the photoelectric type sensor to produce the first electrical output.
5. A system according to claim 1, in which the characteristic wavelength is 4.4 microns.
6. A system for detecting fire or explosions emitting radiation having a characteristic wavelength and also emitting radiation at other wavelengths, comprising a thermopile detector to sense radiation in a narrow wavelength band including the characteristic wavelength and to produce a first electrical output dependent on the intensity of the sensed radiation, first threshold means connected to receive the first electrical output and to compare its magnitude with a predetermined threshold whereby to produce a first control output when the said magnitude exceeds the threshold, second, substantially instantaneously responsive, radiation sensing means to sense radiation in a narrow wavelength band including one of the other said wavelengths and producing a second electrical output dependent on the intensity of the radiation sensed, second threshold means connected to receive the second electrical output and to compare its magnitude with a predetermined threshold whereby to produce a second control signal when the said magnitude exceeds the threshold, means measuring the ratio of the first and second electrical outputs and producing a third control output only when the ratio of the first electrical to the second electrical output exceeds a predetermined value, and output means responsive to the first, second and third control outputs and operative to produce a fire or explosion indicating output only when all three control outputs exist at the same time.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB80.16385 | 1980-05-17 | ||
| GB8016385A GB2076148B (en) | 1980-05-17 | 1980-05-17 | Improvements in and relating to fire or explosion detection |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1124361A true CA1124361A (en) | 1982-05-25 |
Family
ID=10513495
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA377,355A Expired CA1124361A (en) | 1980-05-17 | 1981-05-12 | Fire or explosion detection |
Country Status (6)
| Country | Link |
|---|---|
| US (1) | US4414542A (en) |
| CA (1) | CA1124361A (en) |
| DE (1) | DE3118377A1 (en) |
| FR (1) | FR2482753B1 (en) |
| GB (1) | GB2076148B (en) |
| IL (1) | IL62886A (en) |
Families Citing this family (19)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2505495A1 (en) * | 1981-05-05 | 1982-11-12 | Centre Nat Rech Scient | METHOD AND DEVICES FOR MEASURING TEMPERATURE OF A MICROWAVE BODY |
| US4679156A (en) * | 1981-05-21 | 1987-07-07 | Santa Barbara Research Center | Microprocessor-controlled fire sensor |
| US4765244A (en) * | 1983-04-15 | 1988-08-23 | Spectronix Ltd. | Apparatus for the detection and destruction of incoming objects |
| GB8324136D0 (en) * | 1983-09-09 | 1983-10-12 | Graviner Ltd | Fire and explosion detection and suppression |
| US4603255A (en) * | 1984-03-20 | 1986-07-29 | Htl Industries, Inc. | Fire and explosion protection system |
| US4665390A (en) * | 1985-08-22 | 1987-05-12 | Hughes Aircraft Company | Fire sensor statistical discriminator |
| GB2184585B (en) * | 1985-12-20 | 1989-10-25 | Graviner Ltd | Fire and explosion detection and suppression |
| GB2184584B (en) * | 1985-12-20 | 1989-10-25 | Graviner Ltd | Fire and explosion detection and suppression |
| GB2199656B (en) * | 1987-01-07 | 1990-10-17 | Graviner Ltd | Detection of electromagnetic radiation |
| US5122628A (en) * | 1990-05-25 | 1992-06-16 | Fike Corporation | Sudden pressure rise detector |
| GB9112928D0 (en) * | 1991-06-15 | 1991-08-14 | British Aerospace | Venting a space to relieve pressure generated by an explosion |
| US5612676A (en) * | 1991-08-14 | 1997-03-18 | Meggitt Avionics, Inc. | Dual channel multi-spectrum infrared optical fire and explosion detection system |
| US5726632A (en) * | 1996-03-13 | 1998-03-10 | The United States Of America As Represented By The Administrator Of The National Aeronautics & Space Administration | Flame imaging system |
| US5850182A (en) * | 1997-01-07 | 1998-12-15 | Detector Electronics Corporation | Dual wavelength fire detection method and apparatus |
| US5995008A (en) * | 1997-05-07 | 1999-11-30 | Detector Electronics Corporation | Fire detection method and apparatus using overlapping spectral bands |
| US7324004B2 (en) * | 2003-10-29 | 2008-01-29 | Honeywell International, Inc. | Cargo smoke detector and related method for reducing false detects |
| KR100671045B1 (en) | 2005-07-22 | 2007-01-17 | 주식회사 금륜방재산업 | Flame detector to detect hydrocarbon fire and non hydrocarbon fire |
| DK178262B1 (en) | 2009-02-06 | 2015-10-19 | Ten Cate Active Prot Aps | Pulse and momentum transfer device |
| WO2014039126A2 (en) | 2012-06-06 | 2014-03-13 | Tencate Advanced Armor Usa, Inc. | Active countermeasures systems and methods |
Family Cites Families (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1960218A1 (en) * | 1969-12-01 | 1971-06-03 | Rainer Portscht | Temperature radiation detector for automatic fire detection or flame monitoring |
| FR2151148A5 (en) * | 1971-08-20 | 1973-04-13 | Detection Electro Fse | |
| US3931521A (en) * | 1973-06-29 | 1976-01-06 | Hughes Aircraft Company | Dual spectrum infrared fire detector |
| US3825754A (en) * | 1973-07-23 | 1974-07-23 | Santa Barbara Res Center | Dual spectrum infrared fire detection system with high energy ammunition round discrimination |
| US3859520A (en) * | 1974-01-17 | 1975-01-07 | Us Interior | Optical detection system |
| GB1550334A (en) * | 1975-06-28 | 1979-08-15 | Emi Ltd | Radiation detecting arrangements |
| JPS586996B2 (en) * | 1977-02-15 | 1983-02-07 | 国際技術開発株式会社 | Flame detection method |
| US4101767A (en) * | 1977-05-20 | 1978-07-18 | Sensors, Inc. | Discriminating fire sensor |
| IL54137A (en) * | 1978-02-27 | 1985-02-28 | Spectronix Ltd | Fire and explosion detection apparatus |
| US4206454A (en) * | 1978-05-08 | 1980-06-03 | Chloride Incorporated | Two channel optical flame detector |
| US4220857A (en) * | 1978-11-01 | 1980-09-02 | Systron-Donner Corporation | Optical flame and explosion detection system and method |
| US4296324A (en) * | 1979-11-02 | 1981-10-20 | Santa Barbara Research Center | Dual spectrum infrared fire sensor |
| DE3100482A1 (en) * | 1980-01-17 | 1981-11-19 | Graviner Ltd., High Wycombe, Buckinghamshire | Detection device for fire and explosions |
-
1980
- 1980-05-17 GB GB8016385A patent/GB2076148B/en not_active Expired
-
1981
- 1981-05-09 DE DE19813118377 patent/DE3118377A1/en not_active Withdrawn
- 1981-05-12 CA CA377,355A patent/CA1124361A/en not_active Expired
- 1981-05-15 FR FR8109716A patent/FR2482753B1/en not_active Expired
- 1981-05-15 IL IL62886A patent/IL62886A/en unknown
- 1981-05-15 US US06/265,016 patent/US4414542A/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| IL62886A (en) | 1985-07-31 |
| FR2482753A1 (en) | 1981-11-20 |
| FR2482753B1 (en) | 1985-10-25 |
| IL62886A0 (en) | 1981-07-31 |
| DE3118377A1 (en) | 1982-06-24 |
| GB2076148A (en) | 1981-11-25 |
| GB2076148B (en) | 1984-08-30 |
| US4414542A (en) | 1983-11-08 |
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Legal Events
| Date | Code | Title | Description |
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| MKEX | Expiry |