EP0409266B1 - Branddetektor - Google Patents

Branddetektor Download PDF

Info

Publication number
EP0409266B1
EP0409266B1 EP90113961A EP90113961A EP0409266B1 EP 0409266 B1 EP0409266 B1 EP 0409266B1 EP 90113961 A EP90113961 A EP 90113961A EP 90113961 A EP90113961 A EP 90113961A EP 0409266 B1 EP0409266 B1 EP 0409266B1
Authority
EP
European Patent Office
Prior art keywords
radiation
thermocouple
fire detector
fire
test
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 - Lifetime
Application number
EP90113961A
Other languages
German (de)
English (en)
French (fr)
Other versions
EP0409266A2 (de
EP0409266A3 (en
Inventor
Klaus Dipl.-Ing Schierau
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.)
Minimax GmbH and Co KG
Original Assignee
Preussag AG Feuerschutz
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 Preussag AG Feuerschutz filed Critical Preussag AG Feuerschutz
Publication of EP0409266A2 publication Critical patent/EP0409266A2/de
Publication of EP0409266A3 publication Critical patent/EP0409266A3/de
Application granted granted Critical
Publication of EP0409266B1 publication Critical patent/EP0409266B1/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING SYSTEMS, e.g. PERSONAL 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

  • the invention relates to a fire detector according to the preamble of claim 1.
  • a fire detector is described in DE 25 12 650 C2, which has a sensor element that detects the radiation emitted by a flame. The spectral composition of the radiation is analyzed and an alarm signal is generated depending on the result. Semiconductor components such as photodiodes or photo elements are used as the sensor element. These have the disadvantage that their interference signal spacing, ie the ratio of the useful signal to the interference signal, decreases sharply with increasing ambient temperature, since at high temperatures their interference signal is high, for example as a result of thermal noise, and their sensitivity decreases. The ambient temperature can vary widely when operating fire detectors Fluctuate range.
  • Typical operating temperatures of fire detectors range, for example, from -40 ° C to + 60 ° and higher in the event of a fire, at which the fire detector should still work properly.
  • the response threshold of the useful signal ie the signal that can trigger an alarm, must be greater than the maximum interference signal.
  • thermocouple A fire detector is known from US Pat. No. 2,834,008, the sensor element of which is designed as a thermocouple.
  • the AC voltage signal emitted by the thermocouple is evaluated within a predetermined frequency range.
  • an evaluation unit If the signal amplitudes typical for a fire occur in the range from 3 to 30 Hz, an evaluation unit generates an alarm signal.
  • thermocouples for temperature measurement.
  • the voltage generated by a thermocouple depends on the temperature difference between the measuring point and the reference point.
  • the reference junction temperature must be kept at a known temperature that is as constant as possible.
  • the thermocouple generates a voltage depending on the temperature difference between its measuring point and its reference point.
  • the reference junction is connected to a heat sink, which assumes the temperature of the room as a result of heat conduction. Since the heat sink stores heat, short-term temperature fluctuations of the room follow only slowly, so that a temperature is established over time on the heat sink which corresponds approximately to the mean temperature of the room.
  • the measuring point of the thermocouple has a small heat capacity and can Follow temperature changes quickly. Accordingly, the temperature of the measuring point of the thermocouple is influenced by absorption of radiation energy, which emits a heat source, and / or by heating due to heat conduction, for example by thermal convection. In the event of a fire, both types of heat transfer are effective, ie the thermocouple detects parts of both forms of energy. This increases the sensitivity of the fire detector to the known device.
  • thermocouple emits a signal that is proportional to the temperature difference between the reference point and the measuring point, regardless of the absolute temperature.
  • the absolute temperature of the room does not affect the sensitivity of the fire detector.
  • the interference signal from thermocouples is small over a wide temperature range, since their thermal noise is smaller than that from semiconductor components.
  • the fire detector therefore has an almost constant signal-to-noise ratio over its entire operating temperature range. This makes it possible to select the response threshold for detecting a fire accordingly low, so that fires can be detected early. Since, unlike in the prior art, no semiconductor component is used as the sensor element, which is known to have a low limit temperature, the temperature range in which the fire detector can be used is also enlarged compared to the prior art. The consequence of this is that the fire detector remains functional even at high temperatures, for example in the event of a fire, and can provide information about the course of the fire.
  • thermocouples are connected together to form a thermopile. This measure increases the sensitivity of the fire detector even further.
  • thermocouple is preceded by an optical filter which is transparent to radiation of a wavelength specific to the fire.
  • the flames emit radiation with a characteristic wavelength that differs from the wavelength of other heat sources.
  • the measures mentioned effectively suppress interference radiation from heat sources, such as incandescent lamps, radiators, etc.
  • the alarm signal can be generated depending on the exceeding of a predetermined threshold value of the signal of the thermocouple and / or depending on the flicker frequency of the signal.
  • the frequency of the radiation emanating from a fire can also be used to distinguish the radiation emanating from a fire from interference radiation.
  • the frequency at which a flame emits radiation is normally in a frequency range from 0.5 to 10 Hz. If the evaluation of the signals from the thermocouple is limited to this frequency range, the interference signal from the interference radiation of other heat sources with deviating frequencies can , such as ambient light with a frequency of 0 Hz or radiation from an incandescent lamp with a frequency of 100 Hz, do not distort the result.
  • the response of the fire detector to fires becomes even more selective and therefore more reliable.
  • thermocouple which can receive test radiation and which emits a test signal to the evaluation unit which, depending on its size, generates a state signal indicating the functional state of the fire detector, and that A protective glass is connected upstream of the thermocouple and the test sensor, which is broadband transparent to radiation.
  • Fire detectors which among other things also evaluate the radiation for fire detection, are naturally sensitive to contamination, since the radiation is already absorbed by dirt particles before they reach the radiation-sensitive surface of the sensor element. This reduces the sensitivity of the fire detector and, at a certain degree of contamination, the fire detector can no longer function properly. This is also critical because the other electrical functions of the fire detector still work properly when contaminated, so that an electrical test cannot provide any information about the functionality of the band detector.
  • at least two sensor elements namely the thermocouple and the test sensor, are preceded by a protective glass. This is exposed to the ambient air and can become dirty. The permeability of the protective glass for broadband radiation is determined with the help of the test sensor.
  • thermocouple Its spectral sensitive speed can be in a different wavelength range than the radiation detected by the thermocouple, since it can be assumed that the dirt on the protective glass generally attenuates the incident radiation over a broad band.
  • the fire detector is functional both with regard to its electrical function and with regard to its ability to detect radiation from a fire.
  • the aforementioned embodiment of the invention can be developed in a sensible manner such that the test radiation is modulated and a demodulator module is provided in the evaluation unit for demodulating the test signal. It is thereby achieved that the signal which is caused by the test radiation differs significantly from the signal of the radiation from other radiation sources.
  • the test signal thus has a high signal-to-noise ratio, so that the degree of contamination of the protective glass can be determined with high reliability.
  • thermopile 16 arranged in the upper circuit branch in FIG. 1 receives radiation 10 through an optical radiation-transmissive cover 12, from which an interference filter 14 passes a wavelength range characteristic of a fire.
  • the thermopile 16 has a reference junction which is connected to a heat sink 18. This consists of a heat-storing material, such as ceramic, and is exposed to the ambient temperature of the room. The heat storage causes short-term temperature fluctuations in the room to be averaged out, so that an average temperature Tm is established on the heat sink 18.
  • the measuring point of the thermopile 16 is supplied with the radiation transmitted by the interference filter 14, which heats it. Furthermore, a heat flow 20 with the temperature Tw can also act on the measuring point. This heat flow 20 can arise, for example, as a result of heat convection in the event of a fire and is therefore used in addition to the radiation 10 for fire detection. A temperature T1 thus arises at the measuring point of the thermopile 16, which has arisen from different energy transfer, namely through thermal convection and thermal radiation.
  • the measuring point has a smaller heat capacity than the reference point thermally connected to the heat sink 18, so that it can follow short-term fluctuations in the radiation 10 and / or the heat flow 20.
  • the temperature difference between the measuring point and the reference point of the thermopile 16 generates after Seebeck effect an electrical voltage, which is amplified by a matching amplifier 22, the impedance of which is matched to the internal resistance of the thermopile 16.
  • the output signal of the adaptation amplifier 22 is fed to an amplifier 24, a frequency analyzer 26 and a differential amplifier 28.
  • Limit modules 30, 32 and 34 are connected downstream of these modules 24, 26, 28.
  • the amplifier 24 and the limit indicator 30 work together in such a way that they emit a signal to a logic module 68 at a predetermined temperature difference between the measuring point and the comparison point of the thermopile 16.
  • the frequency analyzer 26 determines whether a flicker frequency is present in the signal from the thermopile and emits a corresponding signal to the link module 68 via the limit value detector 32.
  • the differential amplifier 28 is used to determine the sign of the temperature change. The sign can again be used to determine whether the temperature of the measuring point of the thermopile 16 is increasing or decreasing. This information can be used to conclude, for example, that the fire has subsided.
  • the lower circuit branch of the fire detector is constructed in the same way as the upper circuit branch, its corresponding components 42 to 64 therefore do not need to be explained in detail except for a few differences.
  • no heat flow acts on the measuring point of the thermopile 46, so that only the radiation energy of the radiation 10 is evaluated.
  • the link module 68 links the signals of the limit indicators 30 to 64 according to predetermined linking rules that are stored in a program block 70.
  • an alarm signal can then be generated at the output 72 of the link module 68, which signals a fire condition when the temperature differences of the heating columns 16 and 46 exceed a predetermined value, the frequency analyzers 26 and 56 signal a certain flicker frequency and when the differential amplifiers 28 and 58 also signals deliver that correspond to a positive slope.
  • the signals of limit value modules 30 to 34 and 60 to 64 are also conceivable, which define a dangerous state.
  • the signals of the modules 24 to 28 and 54 to 58 are also fed to an output module 66 which, after a parallel-serial conversion, transmits them via an output 74 to a control center (not shown). These signals can be further evaluated there.
  • the upper circuit branch according to FIG. 1 is developed in such a way that two test sensors 82, 84 are arranged next to the thermopile 16.
  • the processing of the signal emitted by the thermopile 16 corresponds to that described in FIG. 1. An exact explanation of this is therefore omitted.
  • the radiation 10 falls on a protective glass 80 which transmits the radiation in a wide wavelength range.
  • the interference filter 14 filters out a fire-specific wavelength range from this wavelength range, which reaches the thermopile 16.
  • Another part of the radiation 10 reaches the test sensors 82 and 84. These are silicon photodiodes, whose maximum spectral sensitivity is in the range below 1 micron wavelength of the radiation lies.
  • test sensors are connected in series on their opposite-pole electrodes and connected to a differential amplifier 88, which amplifies the test signal output by sensors 82, 84.
  • the protective glass 80 can become dirty during operation of the fire alarm, which is indicated by a dirt coating 92 in FIG. 2.
  • This dirt coating weakens the intensity of the incident radiation 10 and thereby reduces the sensitivity of the fire detector for detecting fires.
  • the radiation 10 of the room is mixed with a test radiation 94 having a certain wavelength, which is adapted to the spectral sensitivity of the sensors 82, 84, and a certain intensity.
  • This test radiation 94 is additionally modulated with a frequency.
  • the signal from the test sensors 82, 84 now contains components which originate both from the test radiation 94 and from the spatial radiation 10.
  • the signal is amplified in the differential amplifier 88 and fed to a bandpass filter 90, which serves as a demodulator.
  • the deviation from this limit value is a measure of the attenuation of the total radiation through the protective glass 80.
  • the result of the comparison is then passed on to the transmission module 86 via a digital output of the bandpass filter 90, which forwards it to the central station after a parallel-series conversion.
  • the control center can use this to infer the functionality of the fire detector and appropriate countermeasures initiate.
  • FIG. 2 can be used not only for fire detectors that are equipped with thermocouples or thermopiles, but also for other types of sensor elements that are provided with a protective glass. It is only necessary for this that the test radiation has characteristic differences from the radiation which are evaluated for the detection of a fire. Such characteristic differences can lie in the modulation frequency, in the wavelength of the radiation and in the polarization state of the radiation.

Landscapes

  • Business, Economics & Management (AREA)
  • Emergency Management (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Fire-Detection Mechanisms (AREA)
  • Fire Alarms (AREA)
EP90113961A 1989-07-21 1990-07-20 Branddetektor Expired - Lifetime EP0409266B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3924250 1989-07-21
DE3924250A DE3924250A1 (de) 1989-07-21 1989-07-21 Branddetektor

Publications (3)

Publication Number Publication Date
EP0409266A2 EP0409266A2 (de) 1991-01-23
EP0409266A3 EP0409266A3 (en) 1991-08-14
EP0409266B1 true EP0409266B1 (de) 1996-01-17

Family

ID=6385582

Family Applications (1)

Application Number Title Priority Date Filing Date
EP90113961A Expired - Lifetime EP0409266B1 (de) 1989-07-21 1990-07-20 Branddetektor

Country Status (4)

Country Link
EP (1) EP0409266B1 (https=)
AT (1) ATE133284T1 (https=)
DE (2) DE3924250A1 (https=)
ES (1) ES2084624T3 (https=)

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4331574C2 (de) * 1993-09-16 1997-07-10 Heimann Optoelectronics Gmbh Infrarot-Sensormodul
RU2170951C2 (ru) * 1999-10-18 2001-07-20 Закрытое акционерное общество Производственное объединение "Спецавтоматика" Автономное пожарное сигнально-пусковое устройство
DE10011411C2 (de) 2000-03-09 2003-08-14 Bosch Gmbh Robert Bildgebender Brandmelder
DE10154923A1 (de) * 2001-11-08 2003-06-05 Klaus Palme Verfahren zur Gewinnung elektrischer Energie aus den Temperaturschwankungen der Luft
GB2426578A (en) 2005-05-27 2006-11-29 Thorn Security A flame detector having a pulsing optical test source that simulates the frequency of a flame
GB2426577A (en) 2005-05-27 2006-11-29 Thorn Security An optical detector with a reflector outside of its housing, and a plurality of sensors inside of its housing
RU2744900C1 (ru) * 2020-03-23 2021-03-17 Закрытое акционерное общество "Производственное объединение "Спецавтоматика" Способ автоматического контроля пожарной опасности и автономное пожарное сигнально-пусковое устройство для его реализации

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2834008A (en) * 1953-04-28 1958-05-06 Petcar Res Corp Flame detector system
US3518654A (en) * 1967-05-16 1970-06-30 American District Telegraph Co Method and apparatus for detecting a condition
CH565421A5 (https=) * 1974-05-10 1975-08-15 Cerberus Ag
JPS5727109Y2 (https=) * 1974-07-20 1982-06-12
CA1023971A (en) * 1975-04-18 1978-01-10 Canada Wire And Cable Limited Variable temperature sensor
US4003038A (en) * 1975-06-09 1977-01-11 Multi-State Devices Ltd. Thermal discriminator for sensing variations in the heat exchange properties of a medium
CH628171A5 (de) * 1978-04-25 1982-02-15 Cerberus Ag Flammenmelder.
GB2089503B (en) * 1980-12-12 1984-07-18 Graviner Ltd Fire and explosion detection
GB2175686A (en) * 1985-05-28 1986-12-03 Graviner Ltd Fire or explosion detection arrangement
DE8528659U1 (de) * 1985-10-08 1987-03-19 Heimann Gmbh, 6200 Wiesbaden Infrarotdetektor

Also Published As

Publication number Publication date
DE59010065D1 (de) 1996-02-29
DE3924250A1 (de) 1991-02-07
ES2084624T3 (es) 1996-05-16
EP0409266A2 (de) 1991-01-23
EP0409266A3 (en) 1991-08-14
DE3924250C2 (https=) 1992-04-23
ATE133284T1 (de) 1996-02-15

Similar Documents

Publication Publication Date Title
DE69032686T2 (de) Infrarotsensor geeignet für anwendungen zur feuerbekämpfung
US5339070A (en) Combined UV/IR flame detection system
US4206454A (en) Two channel optical flame detector
DE69901080T2 (de) Sensor mit mehreren Arrays und Verfahren zur Identifizierung von Ereignissen in dem er benützt wird
EP0966660B1 (de) Thermopile-sensor und strahlungsthermometer mit einem thermopile-sensor
DE69028046T2 (de) Strahlungsabschirmung für thermoelektrisch gekühlte Infrarotdetektoren
DE69820308T2 (de) Mikrotechnologischer ableitender optisch-thermischer Gassensor
DE69827389T2 (de) Photothermischer mikrotechnologisch hergestellter gassensor
DE2057221C3 (de) Vorrichtung zur Feststellung von Flammen mittels wenigstens zwei photoelektrischen Anordnungen
US4463260A (en) Flame detector
EP1343446B1 (de) Blendschutzvorrichtung für schweisserschutzmasken
DE2225319B2 (de) Nichtdispersiver optischer Strahlung sanalysator
EP0409266B1 (de) Branddetektor
WO1981000636A1 (fr) Dispositif de detection avec detecteur
EP1062647A1 (de) Brandmelder
DE2413482C3 (de) Einrichtung zur Überwachung einer einzelnen Brennerflamme in einer eine Mehrzahl von Brennerflammen aufweisenden Brennkammer
DE19654773C1 (de) Verfahren und Vorrichtung zur betrieblichen Messung der Temperatur in mindestens einer Kochzone eines Kochfeldes mit einer Glaskeramikplatte
DE2709866C2 (de) Vorrichtung zur Feststellung von Schwebeteilchen
DE3149869C2 (https=)
EP2758948B1 (de) Brandmelder mit sensorfeld
DE10245822A1 (de) Verfahren und Gasmesszelle zur Detektion unterschiedlicher Gase
DE102014018722B3 (de) Verfahren, SiC-Halbleiterdetektor und dessen Verwendung und Detektoranordnung diesen aufweisend zur Detektion von Sonnenlicht
DE60003885T2 (de) Thermischer detektor mit begrenztem sichtwinkel
AT390326B (de) Verfahren zur temperaturmessung eines objektes mittels strahlungspyrometrie
EP3074740B1 (de) Leuchte und verfahren zur temperaturüberwachung

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

AK Designated contracting states

Kind code of ref document: A2

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

RBV Designated contracting states (corrected)

Designated state(s): AT BE DE ES FR GB NL

PUAL Search report despatched

Free format text: ORIGINAL CODE: 0009013

AK Designated contracting states

Kind code of ref document: A3

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

17P Request for examination filed

Effective date: 19910912

17Q First examination report despatched

Effective date: 19940627

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): AT BE DE ES FR GB NL

REF Corresponds to:

Ref document number: 133284

Country of ref document: AT

Date of ref document: 19960215

Kind code of ref document: T

REF Corresponds to:

Ref document number: 59010065

Country of ref document: DE

Date of ref document: 19960229

GBT Gb: translation of ep patent filed (gb section 77(6)(a)/1977)

Effective date: 19960227

ET Fr: translation filed
REG Reference to a national code

Ref country code: ES

Ref legal event code: FG2A

Ref document number: 2084624

Country of ref document: ES

Kind code of ref document: T3

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

RAP2 Party data changed (patent owner data changed or rights of a patent transferred)

Owner name: MINIMAX GMBH

26N No opposition filed
NLT2 Nl: modifications (of names), taken from the european patent patent bulletin

Owner name: MINIMAX GMBH

REG Reference to a national code

Ref country code: GB

Ref legal event code: IF02

BECN Be: change of holder's name

Owner name: *MINIMAX HOLDING G.M.B.H. & CO. K.G.

Effective date: 20050928

REG Reference to a national code

Ref country code: ES

Ref legal event code: PC2A

REG Reference to a national code

Ref country code: FR

Ref legal event code: TP

Ref country code: FR

Ref legal event code: CD

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: ES

Payment date: 20070704

Year of fee payment: 18

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: AT

Payment date: 20070607

Year of fee payment: 18

BECN Be: change of holder's name

Owner name: *MINIMAX G.M.B.H. & CO. K.G.

Effective date: 20050928

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: BE

Payment date: 20070711

Year of fee payment: 18

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 20070611

Year of fee payment: 18

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 20080710

Year of fee payment: 19

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: NL

Payment date: 20080619

Year of fee payment: 19

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 20080620

Year of fee payment: 19

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: AT

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20080720

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST

Effective date: 20090331

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FR

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20080731

REG Reference to a national code

Ref country code: ES

Ref legal event code: FD2A

Effective date: 20080721

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: ES

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20080721

GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 20090720

NLV4 Nl: lapsed or anulled due to non-payment of the annual fee

Effective date: 20100201

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20090720

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20100202

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: BE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20080731

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: NL

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20100201