EP0113046B1 - Heat detector - Google Patents
Heat detector Download PDFInfo
- Publication number
- EP0113046B1 EP0113046B1 EP19830111869 EP83111869A EP0113046B1 EP 0113046 B1 EP0113046 B1 EP 0113046B1 EP 19830111869 EP19830111869 EP 19830111869 EP 83111869 A EP83111869 A EP 83111869A EP 0113046 B1 EP0113046 B1 EP 0113046B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- light emitting
- fire
- light
- optical fiber
- output
- 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
- 239000013307 optical fiber Substances 0.000 claims description 31
- 239000004033 plastic Substances 0.000 description 9
- 229920003023 plastic Polymers 0.000 description 9
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 3
- 238000005286 illumination Methods 0.000 description 3
- 230000007613 environmental effect Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 1
- 230000004927 fusion Effects 0.000 description 1
- 230000036039 immunity Effects 0.000 description 1
- 239000000155 melt Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 230000001360 synchronised effect Effects 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G08—SIGNALLING
- G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
- G08B17/00—Fire alarms; Alarms responsive to explosion
- G08B17/06—Electric actuation of the alarm, e.g. using a thermally-operated switch
-
- 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
Definitions
- This invention relates to a heat detector comprising of an optical fiber, which is vulnerable to fusing at a low temperature, as heat sensing element according to the preamble of the patent claim.
- Such heat detectors are used for instance in fire detecting systems.
- a fire detector which comprises an optical fiber, stable to approximately 57°C, which melts above approximately 68,5°C.
- heat detectors use optical fibers being vulnerable in a low temperature range of some 60--300°C as heat sensing wires and which detect fires by decrease in light reaching the photoelectric elements as caused when the optical fibers are damaged by heat or flame in case of fire, and the light from the light emitting elements leaks out through the damaged portions.
- these heat detectors use an optical fiber which is composed of only a plastic core fusing at a low temperature (some 60-300°C), an optical fiber with its core and clad layer made of plastic fusing at a low temperature, or an optical fiber with its core made of quartz glass which does not fuse at a low temperature and its clad layer made of plastic fusing at a low temperature.
- the ones composed of the plastic core alone or the core and clad layer, both being made of plastic fuse and open with heat from or flame of fire while in the case of the one composed of the quartz glass core and the plastic clad layer, only the clad layer fuses and the core does not open.
- optical fibers have an open or partial fusion caused by heat or flame in case of fire, all or part of the light from the light source leaks out through the damaged portion, and consequently the photoelectric element receives no light or only a part of the light from the light source.
- 1 is an optical fiber with its core and clad layer made of plastics having different refraction rates and which fuses at a low temperature (some 60-300°C)
- 2 is a light emitting element such as a light emitting diode provided at one end of optical fiber
- 3 is a light emitting current feed circuit to feed light emitting current to light emitting element
- 4 is a modulation circuit to modulate the light emitting current from light emitting current feed circuit 3 by signal with specific frequency f from oscillator 5 and to feed the modulated light to light emitting element
- 6 is a photoelectric element such as solar cell provided at the other end of optical fiber
- 7 is an amplifier to amplify the output of photoelectric element
- 8 is a bandpass filter through which only the output modulated by specific frequency f out of the amplified output from amplifier 7 can pass
- 9 is a fire discriminating circuit comprising a comparator which gives out a fire signal when the
- the heat detector of this composition operates as follows.
- the light emitting current from light emitting current feed circuit 3 is normally modulated by modulation circuit 4 and fed to light emitting element 2. With this modulated light emitting current, light emitting element 2 emits modulated light to optical fiber 1.
- photoelectric element 6 receives the modulated light from light emitting element 2 through optical fiber 1.
- the output of photoelectric element 6 is amplified by amplifier 7, and then fed to fire discriminating circuit 9 through bandpass filter 8. Fire discriminating circuit 9 does not give out a fire signal as long as the modulated light output is above the predetermined level.
- the light emitting current from light emitting current feed circuit 3 a pulsed output, to modulate the light emitting current pulse by the output of oscillator 5 in modulation circuit 4 and to feed the modulated light emitting current pulse to light emitting element 2.
- operation of amplifier 7 or fire discriminating circuit 9 is synchronized with light emitting current output of light emitting current feed circuit 3.
- an optical fiber which is composed of only plastic core fusing at a low temperature or an optical fiber with its core made of quartz glass which does not fuse at a low temperature and its clad layer made of plastic fusing at a low temperature.
- occurrence of a fire is discriminated by emitting modulated light to the optical fiber from the light emitting element and checking if there is attenuation in the modulated light intensity reaching the photoelectric element. Therefore, it offers a heat detector using an optical fiber as heat sensing wire which is capable of readily discriminating fire by detecting, without fail, such attenuation of light from the light source as caused by damage in the optical fiber in case of fire.
- the drawing is a schematic diagram of an embodiment of the heat detector according to this idea.
Landscapes
- Business, Economics & Management (AREA)
- Emergency Management (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Fire-Detection Mechanisms (AREA)
- Measuring Temperature Or Quantity Of Heat (AREA)
- Light Guides In General And Applications Therefor (AREA)
Description
- This invention relates to a heat detector comprising of an optical fiber, which is vulnerable to fusing at a low temperature, as heat sensing element according to the preamble of the patent claim.
- Such heat detectors are used for instance in fire detecting systems. From the BE-A-881 994 is known a fire detector which comprises an optical fiber, stable to approximately 57°C, which melts above approximately 68,5°C. In general such heat detectors use optical fibers being vulnerable in a low temperature range of some 60--300°C as heat sensing wires and which detect fires by decrease in light reaching the photoelectric elements as caused when the optical fibers are damaged by heat or flame in case of fire, and the light from the light emitting elements leaks out through the damaged portions.
- For their heat sensing wires these heat detectors use an optical fiber which is composed of only a plastic core fusing at a low temperature (some 60-300°C), an optical fiber with its core and clad layer made of plastic fusing at a low temperature, or an optical fiber with its core made of quartz glass which does not fuse at a low temperature and its clad layer made of plastic fusing at a low temperature. Of these optical fibers, the ones composed of the plastic core alone or the core and clad layer, both being made of plastic, fuse and open with heat from or flame of fire while in the case of the one composed of the quartz glass core and the plastic clad layer, only the clad layer fuses and the core does not open. If these optical fibers have an open or partial fusion caused by heat or flame in case of fire, all or part of the light from the light source leaks out through the damaged portion, and consequently the photoelectric element receives no light or only a part of the light from the light source.
- In practice, however, there exist the sunlight, illumination light etc. around the optical fiber. If the optical fiber opens or partially fuses due to heat or flame in case of fire, the environmental light such as the sunlight, illumination light or light from flame enters the optical fiber from the damaged portion. Therefore, even if the optical fiber is damaged by fire, the photoelectric element receives the environmental lights and the light from flame entering through the damaged portion in lieu of the light from the light source, and accordingly there is scarcely . any change in light intensity reaching the photoelectric element before and after the optical fiber is damaged, and it is quite difficult to discriminate the fire.
- It is an object of this invention to provide a heat detector which uses an optical fiber as the heat detecting element and is capable of readily discriminating a fire by detecting, without fail, a decrease of light caused by damage in the optical fiber due to fire. Another object of this invention is to provide a heat detector which shows an improved noise immunity over the prior art heat detectors using optical fibers.
- The hereinbefore defined objects of this invention are achieved by the use of the heat detector which is defined in the preamble of the specification by the characterizing features of the patent claim.
- The invention will now be more specifically described in the following by way of example only and with reference to the accompanying drawing, wherein 1 is an optical fiber with its core and clad layer made of plastics having different refraction rates and which fuses at a low temperature (some 60-300°C), 2 is a light emitting element such as a light emitting diode provided at one end of
optical fiber 1, 3 is a light emitting current feed circuit to feed light emitting current to lightemitting element 2, 4 is a modulation circuit to modulate the light emitting current from light emittingcurrent feed circuit 3 by signal with specific frequency f fromoscillator 5 and to feed the modulated light to lightemitting element 2, 6 is a photoelectric element such as solar cell provided at the other end of optical fiber 1, 7 is an amplifier to amplify the output of photoelectric element 6, 8 is a bandpass filter through which only the output modulated by specific frequency f out of the amplified output from amplifier 7 can pass, and 9 is a fire discriminating circuit comprising a comparator which gives out a fire signal when the output through the bandpass filter has fallen below the predetermined level. - In normal condition, the heat detector of this composition operates as follows. The light emitting current from light emitting
current feed circuit 3 is normally modulated by modulation circuit 4 and fed tolight emitting element 2. With this modulated light emitting current, light emittingelement 2 emits modulated light to optical fiber 1. On the other hand photoelectric element 6 receives the modulated light fromlight emitting element 2 through optical fiber 1. The output of photoelectric element 6 is amplified by amplifier 7, and then fed to fire discriminating circuit 9 through bandpass filter 8. Fire discriminating circuit 9 does not give out a fire signal as long as the modulated light output is above the predetermined level. - If a fire breaks out and optical fiber 1 fuses to open with heat from or flame of the fire, propagation of the modulated light from
light emitting element 2 is interrupted at the opened portion, and external light such as sunlight, illumination light, and light of the flame enter optical fiber 1 from the opened portion. Consequently, a photoelectric element 6 no longer receives the modulated light fromlight emitting element 2 but the external light and light of the flame, thus generating output which does not contain modulated light portion with specific frequency f, and which is amplified by amplifier 7 and sent to bandpass filter 8. Nevertheless, since this output sent to bandpass filter 8 contains no modulated light portion with frequency f, no output develops at bandpass filter 8. As a result of this, the modulated light output in fire discriminating circuit 9 falls below the predetermined value, i.e. O, fire discriminating circuit 9 determines it as fire and sends a fire signal to fire control panel which is not shown in the drawing. - It is also feasible to make the light emitting current from light emitting current feed circuit 3 a pulsed output, to modulate the light emitting current pulse by the output of
oscillator 5 in modulation circuit 4 and to feed the modulated light emitting current pulse tolight emitting element 2. In this case, operation of amplifier 7 or fire discriminating circuit 9 is synchronized with light emitting current output of light emittingcurrent feed circuit 3. It is also possible to use an optical fiber which is composed of only plastic core fusing at a low temperature or an optical fiber with its core made of quartz glass which does not fuse at a low temperature and its clad layer made of plastic fusing at a low temperature. According to the present idea, occurrence of a fire is discriminated by emitting modulated light to the optical fiber from the light emitting element and checking if there is attenuation in the modulated light intensity reaching the photoelectric element. Therefore, it offers a heat detector using an optical fiber as heat sensing wire which is capable of readily discriminating fire by detecting, without fail, such attenuation of light from the light source as caused by damage in the optical fiber in case of fire. -
Claims (1)
- A heat detector comprising a light emitting element (2), a circuit (3, 4, 5) which feeds modulated light emitting current to the light emitting element (2), an optical fiber (1) through which the modulated light from the light emitting element is fed and which is vulnerable to breaking, fusing at a low temperature, etc., a photoelectric element (6), which receives light from the optical fiber (1), and a fire discriminating circuit (9) which detects output of the modulated light portion of the output of the photoelectric element (6) to discriminate whether a fire has broken out or not, characterized in that the circuit (4) which feeds the modulated light emitting current is formed in such a way that the modulated light emitting current is intermittently fed to the light emitting element (2), and the fire discriminating circuit (9) is formed in such a way that it detects the output synchronously with the modulated light emitting current output.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP18261082U JPS5988793U (en) | 1982-12-03 | 1982-12-03 | Thermal fire detector |
JP182610/82 | 1982-12-03 |
Publications (3)
Publication Number | Publication Date |
---|---|
EP0113046A2 EP0113046A2 (en) | 1984-07-11 |
EP0113046A3 EP0113046A3 (en) | 1984-12-05 |
EP0113046B1 true EP0113046B1 (en) | 1987-09-16 |
Family
ID=16121297
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP19830111869 Expired EP0113046B1 (en) | 1982-12-03 | 1983-11-26 | Heat detector |
Country Status (4)
Country | Link |
---|---|
EP (1) | EP0113046B1 (en) |
JP (1) | JPS5988793U (en) |
DE (1) | DE3373736D1 (en) |
ES (1) | ES8501552A1 (en) |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2203832B (en) * | 1987-04-16 | 1991-03-20 | Graviner Ltd | Fire detection |
FR2818166B1 (en) * | 2000-12-20 | 2003-10-31 | Coatex Sas | AGENT FOR GRINDING AND / OR DISPERSION OF AQUEOUS SUSPENSION MINERAL MATERIALS. AQUEOUS SUSPENSIONS OBTAINED AND USES THEREOF |
CN116343426B (en) * | 2023-03-20 | 2023-09-08 | 享成安全科技(南京)有限公司 | Cable type linear temperature-sensing fire detector with position indication and use method thereof |
Family Cites Families (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5070890U (en) * | 1973-10-31 | 1975-06-23 | ||
GB1466224A (en) * | 1974-03-20 | 1977-03-02 | Sumitomo Electric Industries | Optical transmission fibres |
JPS5288991U (en) * | 1975-12-26 | 1977-07-02 | ||
US4379289A (en) * | 1979-03-08 | 1983-04-05 | Gte Laboratories Incorporated | Fiber optics security system |
CH639789A5 (en) * | 1979-08-15 | 1983-11-30 | Benno Perren | SELF-MONITORING WARNING SYSTEM. |
-
1982
- 1982-12-03 JP JP18261082U patent/JPS5988793U/en active Granted
-
1983
- 1983-11-26 DE DE8383111869T patent/DE3373736D1/en not_active Expired
- 1983-11-26 EP EP19830111869 patent/EP0113046B1/en not_active Expired
- 1983-12-02 ES ES83528187A patent/ES8501552A1/en not_active Expired
Also Published As
Publication number | Publication date |
---|---|
ES528187A0 (en) | 1984-11-16 |
JPS5988793U (en) | 1984-06-15 |
DE3373736D1 (en) | 1987-10-22 |
JPH0330952Y2 (en) | 1991-06-28 |
EP0113046A3 (en) | 1984-12-05 |
ES8501552A1 (en) | 1984-11-16 |
EP0113046A2 (en) | 1984-07-11 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US4752768A (en) | Intruder detector with anti-obscuring means | |
US3882477A (en) | Smoke and heat detector incorporating an improved smoke chamber | |
US4728794A (en) | Radiation sensing arrangements | |
NO842033L (en) | DISTRIBUTED RADIATION SMOKE DETECTOR | |
EP0078443A2 (en) | Fire detection system | |
US4734575A (en) | Light barrier utilizing two radiation branches each having differently polarized filters | |
EP0113046B1 (en) | Heat detector | |
EP0321965B1 (en) | Accident prevention method and apparatus for monitoring the emission of a laser beam in a work station | |
US4639605A (en) | Fire sensor device | |
US4712096A (en) | Condition responsive detection system and method | |
US4308531A (en) | Light transmission type smoke detector | |
EP0113461A2 (en) | Functional test means of light scattering type smoke detector | |
CA1067597A (en) | Smoke detector | |
EP0113104B1 (en) | Device for detecting fractures in power transmission fibers | |
GB2067749A (en) | Improvements in and Relating to Fire and Explosion Detection | |
GB1560731A (en) | Radiation responsive devices | |
JPH06341650A (en) | Electric stove | |
JP7397934B2 (en) | photoelectric smoke detector | |
JP7150497B2 (en) | photoelectric smoke detector | |
JP2000067339A (en) | Fire detector | |
US3651442A (en) | Detection device | |
JPS5828316Y2 (en) | Kasaikantiki | |
SU598106A1 (en) | Fire alarm | |
US4003039A (en) | Optical fire detection system | |
Stephenson | Automatic fire-detection systems |
Legal Events
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 |
|
17P | Request for examination filed |
Effective date: 19831126 |
|
AK | Designated contracting states |
Designated state(s): BE CH DE FR GB IT LI |
|
PUAL | Search report despatched |
Free format text: ORIGINAL CODE: 0009013 |
|
AK | Designated contracting states |
Designated state(s): BE CH DE FR GB IT LI |
|
17Q | First examination report despatched |
Effective date: 19860422 |
|
GRAA | (expected) grant |
Free format text: ORIGINAL CODE: 0009210 |
|
AK | Designated contracting states |
Kind code of ref document: B1 Designated state(s): BE CH DE FR GB IT LI |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: IT Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT;WARNING: LAPSES OF ITALIAN PATENTS WITH EFFECTIVE DATE BEFORE 2007 MAY HAVE OCCURRED AT ANY TIME BEFORE 2007. THE CORRECT EFFECTIVE DATE MAY BE DIFFERENT FROM THE ONE RECORDED. Effective date: 19870916 Ref country code: FR Free format text: THE PATENT HAS BEEN ANNULLED BY A DECISION OF A NATIONAL AUTHORITY Effective date: 19870916 Ref country code: BE Effective date: 19870916 |
|
REF | Corresponds to: |
Ref document number: 3373736 Country of ref document: DE Date of ref document: 19871022 |
|
EN | Fr: translation not filed | ||
PLBE | No opposition filed within time limit |
Free format text: ORIGINAL CODE: 0009261 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT |
|
26N | No opposition filed | ||
REG | Reference to a national code |
Ref country code: CH Ref legal event code: PFA Free format text: NOHMI BOSAI LTD |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: GB Payment date: 19941014 Year of fee payment: 12 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: DE Payment date: 19941024 Year of fee payment: 12 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: CH Payment date: 19950103 Year of fee payment: 12 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: GB Effective date: 19951126 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: LI Effective date: 19951130 Ref country code: CH Effective date: 19951130 |
|
REG | Reference to a national code |
Ref country code: CH Ref legal event code: PL |
|
GBPC | Gb: european patent ceased through non-payment of renewal fee |
Effective date: 19951126 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: DE Effective date: 19960801 |