EP2093731A1 - Détecteur de fumée optique linéaire doté de plusieurs rayons partiels - Google Patents

Détecteur de fumée optique linéaire doté de plusieurs rayons partiels Download PDF

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Publication number
EP2093731A1
EP2093731A1 EP08101741A EP08101741A EP2093731A1 EP 2093731 A1 EP2093731 A1 EP 2093731A1 EP 08101741 A EP08101741 A EP 08101741A EP 08101741 A EP08101741 A EP 08101741A EP 2093731 A1 EP2093731 A1 EP 2093731A1
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EP
European Patent Office
Prior art keywords
light
detector
measuring light
measuring
spatial part
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP08101741A
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German (de)
English (en)
Inventor
Kurt Dr. Müller
Peter Steiner
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Siemens AG
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Siemens AG
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Publication date
Application filed by Siemens AG filed Critical Siemens AG
Priority to EP08101741A priority Critical patent/EP2093731A1/fr
Publication of EP2093731A1 publication Critical patent/EP2093731A1/fr
Withdrawn legal-status Critical Current

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    • 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
    • G08B17/103—Actuation by presence of smoke or gases, e.g. automatic alarm devices for analysing flowing fluid materials by the use of optical means using a light emitting and receiving device
    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B29/00—Checking or monitoring of signalling or alarm systems; Prevention or correction of operating errors, e.g. preventing unauthorised operation
    • G08B29/18—Prevention or correction of operating errors
    • G08B29/185—Signal analysis techniques for reducing or preventing false alarms or for enhancing the reliability of the system
    • G08B29/188—Data fusion; cooperative systems, e.g. voting among different detectors
    • 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
    • G08B17/11—Actuation by presence of smoke or gases, e.g. automatic alarm devices for analysing flowing fluid materials by the use of optical means using an ionisation chamber for detecting smoke or gas
    • G08B17/113—Constructional details

Definitions

  • the present invention relates to the technical field of fire detection technology.
  • the present invention relates to a device for detecting smoke, which detects an extinction caused by smoke along a linear measuring beam and, depending on the respective weakening, initiates an alarm message.
  • the present invention further relates to a system for detecting smoke with at least two of said smoke detection devices, and to a method for detecting smoke by means of a smoke detection device of the above type.
  • an area of up to 1,400 m 2 can be monitored for the formation of smoke.
  • the distance between a transmitter or a light source and a receiver or a light detector can be up to approximately 100 m.
  • the operating principle is based on the fact that the transmitter emits a focused light beam, especially in the infrared spectral range to the receiver. In a fire, smoke or heat changes the infrared rays.
  • the receiver evaluates the parameters light absorption, frequency development and temporal change of the received light intensity and thus allows a reliable detection of smoke.
  • a disadvantage of such a system is the fact that the transmitter and the receiver must be located at widely spaced locations.
  • modified linear smoke detectors in which a reflector is used, which directs the light beam emitted by the light emitter back to the light receiver, which next or at least is arranged near the light transmitter.
  • a reflector which directs the light beam emitted by the light emitter back to the light receiver, which next or at least is arranged near the light transmitter.
  • HEKATRON security system such a linear smoke detector is known, which has the type designation Boomerang.
  • This smoke detector is described in the complete catalog for fire alarm systems of HEKATRONmaschines GmbH, Brühlmatten 9, D-70295 Sulzberg, valid from 06/2005 on page 164.
  • the Boomerang system consists of a transmitter / receiver unit, a reflector and an interface for the detection of smoke or smoke modulation. Thanks to the linear design with transmitter and receiver, the Boomerang system is used everywhere where due to structural conditions no conventional point detectors can be installed, or where with conventional point detectors optimal protection can no longer be guaranteed.
  • the invention has for its object to simplify the detection of smoke with respect to the apparatusiven requirements of a linear fire detector while ensuring a high detection security and a low false alarm rate.
  • a device for detecting smoke in particular on the basis of a measurement of the extinction of a measuring light.
  • the device has (a) a light source configured to emit a measuring light, (b) a first light detector which is arranged relative to the light source such that a first spatial part of the measuring light after reflection by at least approximately 180 °, ie between 170 ° and 190 °, is incident on an at least partially scattering object on the first light detector, and (c) a second light detector, which is arranged relative to the light source such that a second spatial part of the measurement light after reflection by at least approximately 180 ° at an at least partially scattering object hits the second light detector.
  • the first spatial part of the measuring light and the second spatial part of the measuring light directly adjoin one another.
  • the described optical smoke detection device is based on the finding that the use of at least two different parts of a measuring light can be realized in a simple and effective way, a spacious room monitoring.
  • a part of the measurement beam is also referred to below as partial beam.
  • the size and shape of the different parts of the measuring light are determined by the spatial arrangement or by the optical imaging relationships between the light source and the respective light detector.
  • the two partial beams therefore only include light beams emitted by the light source, which actually reach the respective light detector.
  • the optical smoke detection device can be constructed within a compact arrangement and yet a large area or volume area can be monitored for smoke build-up or penetration.
  • a temporal change of the received light intensity can be evaluated by an evaluation unit connected downstream of the first and / or the second light detector. Since the received light intensity, apart from drifts with regard to the intensity of the measuring light and / or the reflectivity of the respective at least partially scattering object depends mainly on the extinction within the two spatial parts of the measuring light, a significant change in the output signal of the first and / or the second Light detector can be closed to the presence of smoke and thus the presence of a source of fire.
  • Drifts can be eliminated by a signal evaluation, which is based on a so-called compensation principle. This means that the quiescent level is updated and only deviations from this quiescent level trigger an alarm. It is irrelevant whether reflections on objects, on the scattering background or crosstalk from possibly other light signals are responsible for a change in the resting level recorded by the two light detectors.
  • the two partial beams of the measuring light can be transmitted radially outward starting from the light source.
  • a compact smoke detector in which the light source and the two light detectors are arranged close to each other, a large volume and / or surface area can be monitored.
  • the first and / or the second light detector can be a special reflector, which is attached or formed, for example, to the wall of a room to be monitored.
  • the optical smoke detector described also works without special reflectors.
  • the at least partially scattering object can namely be any object which has at least a certain reflectivity.
  • the walls and in particular the side walls of a monitored space are particularly suitable for reflecting the measuring light emitted by the light source back to the two light detectors.
  • the at least partially scattering object can be the same for both partial beams. However, it is also possible that the two partial beams impinge on different objects and are at least partially reflected back by them.
  • the light source may include not only a light-emitting element but also a plurality of light-emitting elements which together generate the measurement light.
  • the measuring light can be generated, for example, by a first light-emitting element, for example a first light-emitting diode, and by a second light-emitting element, for example a second light-emitting diode.
  • the light of the first light-emitting diode can be assigned to the first partial beam and the light of the second light-emitting diode can be assigned to the second partial beam.
  • the beam pair can have a slightly fanned-out geometry, so that a comparatively large area or volume range can be monitored.
  • the use of at least one pair of beams has the advantage that the smoke detector described can be insensitive to an optical interruption of only a partial beam. This can be realized for example by a suitable evaluation of the output signals of the two light detectors, which takes into account the redundancy of the measurements of the extinction within the two partial beams. Thus, for example, by a flying insect in the first part of the first partial beam shaded and shadowed at a later time, the second part of the beam. This sequential shadowing can then be distinguished in a simple manner from an at least approximately uniform darkening by penetrating smoke, which in a good approximation is distributed uniformly over both partial beams.
  • the device additionally has an evaluation unit, which is connected downstream of the first and second light detectors and which is set up for jointly evaluating at least one first output signal of the first light detector and one second output signal of the second light detector.
  • the evaluation unit can thus perform a common signal processing of the two measuring light signals of the first and the second light detector.
  • a redundancy of the extinction measurements along the optical paths of the two partial beams can be utilized. This also allows the fault tolerance of the smoke detector described, for example be improved in the passage of an insect.
  • the evaluation unit is set up to analyze (a) the signal level of at least one of the light detectors, (b) a time change of the signal level of at least one of the light detectors, (c) a cross-correlation between the two signal levels of the two Light detectors, and / or (d) a cross-correlation between the two signal level changes of the two light detectors.
  • the signal level is indicative of the received light intensity.
  • the respective light detector and optionally an amplifier connected downstream of the respective light detector has a linear response, so that the strength of the respective signal level is directly proportional to the respectively received light intensity.
  • the specified signal evaluations are not an exhaustive list of possible evaluation procedures.
  • the evaluation procedures described can also process other measurement results such as, for example, a temperature or further optical attenuation or scattered light intensities. In this way, suitable input variables can be used for different external conditions and an optimal evaluation procedure can be used.
  • the light source is set up to emit a pulsed measuring light
  • the evaluation unit is set up to carry out at least one distance measurement between the light source and the at least partially scattering object.
  • .DELTA.t is the time difference between the emission of a light pulse and the reception of the backscattered light pulse and c the speed of light.
  • Performing a distance measurement has the advantage that an object introduced into the light path can be detected quickly and reliably by a reduced time difference between transmission and reception of a light pulse.
  • an introduced object in the case of the presence of smoke, most of the measuring light is still reflected on the originally scattering object.
  • beam interruptions by a discrete object can be well discriminated against an increasing extinction.
  • the evaluation unit can also analyze a double correlation. For example, a relationship between (a) the measured distance and (b) the correlation between the different signal levels within a pair of beams may be analyzed.
  • the device additionally has a printed circuit board on which the light source and the light detectors are mounted.
  • a cylindrical lens can be used, which converts a conically emitted measurement light into a light form which represents a light line in a cross-sectional plane perpendicular to the propagation direction of the light beam.
  • the light intensity can be focused, for example, in the vertical direction and expanded in the horizontal direction.
  • Such light shaping can be a good compromise between (a) the available light intensity, which should be as large as possible, and (b) the size of the area monitored by the measuring light beam.
  • the device additionally has (a) at least one Fresnel optical system which is arranged in the first spatial part of the measuring light and / or in the second spatial part of the measuring light.
  • a Fresnel optics which is often referred to as a Fresnel lens or as a Fresnel array, thus serves to form the first and / or the second partial beam.
  • Fresnel optics have the advantage over conventional lenses that they can be adapted in a simple manner exactly to the geometry of the respective beam cross-section. In this way, the described Fresnel optical system can contribute to the high efficiency of the backscattered light intensity being received by the respective light detector.
  • the Fresnel optics can be arranged in a partial beam, for example in the vicinity of the respective light detector.
  • the device additionally has at least one secondary reflector, which is arranged in the first spatial part of the measuring light and / or in the second spatial part of the measuring light.
  • a secondary reflector has the advantage that the component (s) light source and / or light detector can be mounted in different orientations, for example on a printed circuit board.
  • the secondary reflector in the measuring light emitted by the light source, it is therefore not necessary for the original direction of the measuring light emitted by the light source to coincide with the direction in which the at least partially scattering object is located.
  • the secondary reflector can provide a suitable beam deflection of the measuring light.
  • the described secondary reflector images the first spatial part of the measuring light onto the first light receiver and / or the second spatial part of the measuring light onto the second light receiver.
  • the secondary mirror may have a negative focal length. The negative focal length thus increases the effective detection range of the respective light detector. So that can reliably ensure that a projection spot of the light source on the at least partially scattering object is actually detected by the respective light detector.
  • the secondary reflector can also have different facets, one facet being assigned to each one light detector.
  • a plurality of partial beams can advantageously be deflected in such a way by a common secondary reflector that in each case a partial beam impinges on a light detector.
  • secondary reflector is used because the at least partially scattering object is absolutely necessary for the operation of the described linear detector. This can therefore be regarded as a primary reflector.
  • the device additionally has (a) a housing and (b) at least one optical element for an optical imaging of the first and / or the second spatial part of the measuring light.
  • the optical element is integrated in the housing.
  • the optical element is in particular a refractive optical element such as a lens.
  • the optical element may also be the Fresnel optic described above.
  • the design of the optical element as an integral part of the housing or the cover of the described linear optical smoke detector has the advantage that it can be produced inexpensively.
  • the entire smoke detector can be realized in a flat and / or inconspicuous construction.
  • the optical element may preferably be attached to the inside of the housing so that it is not visible from the outside and also exposed to less dirt. In addition, the optical element is automatically positioned correctly in a correct position mounting of the housing.
  • the optical element is not limited to conventional mostly round lenses.
  • the optical element is a Fresnel optic
  • a front side of the housing of the described smoke detector can be optimally utilized for the formation of a large-area optical element.
  • the housing may be formed in various shapes.
  • the housing may be configured with respect to a simple mounting on flat walls or a flat ceiling or for mounting in a corner of a space to be monitored.
  • the device additionally comprises a holder to which the housing is pivotally mounted.
  • a pivotally mounted housing has the advantage that the orientation of all optical components can be easily changed. Thereby, the optical axis or the optical axes of the smoke detector inclined in a simple manner and so the area of a room, which is monitored by the measuring beam or by the two sub-beams, adapted to the particular circumstances.
  • the device additionally comprises (a) a third light detector which is arranged relative to the light source such that a third spatial part of the measurement light, after being reflected by at least approximately 180 ° on an object which is at least partially scattering, third light detector meets, and (b) a fourth light detector, which is arranged relative to the light source such that a fourth spatial part of the measurement light after reflection by at least approximately 180 °, ie between 170 ° and 190 °, on an at least partially scattering object meets the fourth light detector.
  • the use of at least two further sub-beams and at least two further light detectors, wherein one light detector is associated with a sub-beam, has the advantage that, starting from a single smoke detector, a particularly large area or a particularly large volume within a surveillance area on the formation of smoke can be monitored.
  • the described further partial beams can be formed as well as the first two partial beams or be influenced by suitable optical components or interact with these. This applies in particular to a contiguity of the third spatial part and the fourth spatial part of the measuring light, so that the third partial beam and the fourth partial beam form a double beam.
  • the third and the fourth partial beam can also be generated by a light-emitting element other than the first and the second partial beam.
  • the other light-emitting element is also considered to belong to the light source.
  • the described linear smoke detector is not limited to the use of four partial beams or to the use of two double beams. In order to achieve an even better area or volume coverage in the fire monitoring, in principle any number of double beams can be used. It is then possible that the extinction be measured separately by smoke particles in each of the individual sub-beams can. Furthermore, the evaluation unit can then be set up in such a way that the measurement signals of all the light detectors can be recorded separately and possibly evaluated together.
  • the smoke detector described can cover, for example, an angular range of 90 °.
  • the smoke detector can be oriented such that the optical axes of the individual partial or double beams are parallel to the ceiling of the room.
  • the volume area just below the ceiling can be completely monitored.
  • an angular range of approximately 90 degrees is detected by means of four to eight double beams.
  • N double beams evenly distributed over an angular range of approximately 90 ° - ⁇ / 2 can then start from the described smoke detector.
  • ⁇ 90 ° / N.
  • the angle between an outer double jet and a wall of a space to be monitored can also be selected to be somewhat larger than ⁇ / 2. As a result, it could be ensured, for example, that no wall projections project into the region of the partial beam located at the edge of the fan beam.
  • a system for detecting smoke is described in particular on the basis of a measurement of the extinction of a measuring light.
  • the system described has at least two devices of the above type.
  • the described system is based on the finding that a particularly large angular range and thus a particularly large area or volume range of a room can be covered by a combination of at least two of the smoke detection devices described above.
  • four smoke detectors each covering an angular range of 90 °, can be placed in the middle of a room so that each smoke detector monitors one quadrant of the room.
  • the optical axes of the individual smoke detectors When attached to the ceiling of the room, the optical axes of the individual smoke detectors can also be tilted slightly downwards.
  • the volume effectively monitored by the entire system can be further increased.
  • a method for detecting smoke is specified, in particular on the basis of a measurement of the extinction of a measuring light.
  • the specified method comprises (a) emitting a measurement light by means of a light source, (b) receiving a first spatial part of the measurement light after reflection by at least approximately 180 ° on an at least partially scattering object by means of a first light detector, and (b) receiving a second spatial part of the measuring light after reflection by at least approximately 180 ° on an at least partially scattering object by means of a second light detector, in which the first spatial part of the measuring light and the second spatial part of the measuring light directly adjoin one another.
  • the specified method is based on the knowledge that a spacious room monitoring can be realized by using at least two different parts or partial beams of a measuring light.
  • the size and shape of the different parts of the measuring light are determined according to the invention by the spatial arrangement and by the optical imaging relationships between the light source and the respective light detector.
  • the two adjoining partial beams of the measuring light which form a so-called beam pair, may preferably have a slightly fanned-out geometry. As a result, a comparatively large area or volume range can be monitored. A targeted focusing of the partial beams on a given reflector is not required. Thus, the specified method is insensitive to misalignments.
  • FIG. 1a shows in a cross-sectional view of a smoke detector with four double beams, which are emitted by a light emitting diode and received after reflection on a side wall of a space of a total of eight photodiodes.
  • FIG. 1b shows the in FIG. 1 illustrated smoke detector in a plan view.
  • FIG. 2 shows the installation of a smoke detector, which uses four double beams for smoke detection, in the corner of a room to be monitored.
  • FIG. 3 shows a system with four smoke detectors, each of which uses four double beams for smoke detection, in the middle of a room to be monitored.
  • FIG. 4 shows in a perspective view the assembly of in FIG. 1 shown smoke detector on a side wall of a space to be monitored.
  • FIG. 5 shows in a perspective view the assembly of in FIG. 1 shown smoke detector in a corner of a room to be monitored.
  • FIG. 6 shows in a schematic representation of a smoke detector and a holder which allows mounting of the smoke detector with different angles of inclination of the measuring light.
  • FIG. 1a shows in a cross-sectional view of a smoke detection device 100, which is also referred to as a smoke detector in the context of this application.
  • the smoke detector 100 uses a measuring light 135 for detecting smoke with a total of four double beams, which are emitted from a light source 130 in the radial direction and in a fanned outward manner and received after reflection on a side wall of a space of a total of eight photodiodes.
  • the side wall therefore serves as a primary reflector for the smoke detector 100 described herein.
  • the light source 130 for each double beam each have a light emitting diode.
  • a sufficiently high and in particular a sufficiently highly focused intensity of the measuring light can be provided.
  • each light-emitting diode 130 In order to transmit the measuring light 135 preferably along a beam axis 135a, each light-emitting diode 130 also has an optical system 134.
  • the optics 134 may, for example, be a cylinder optic which imparts a spatial shape to the measurement light 135 so that an illumination row is formed on a side wall, not shown, of a space to be monitored, which is hit by the measurement light 135.
  • the optic 134 may also be part of the housing 110. In any case, optics 134 should be positioned as accurately as possible relative to the photodiodes, respectively, to the circuit board.
  • the smoke detector 100 has a housing 110, in which, fixed by means of a holder 112, a circuit board 120 is arranged.
  • a circuit board 120 On the printed circuit board 120, a plurality of electronic and optoelectronic components 121 are preferably mounted using the known SMD (Surface Mount Device) technology, which are electrically connected to each other in a suitable manner via interconnects and pads not shown.
  • SMD Surface Mount Device
  • a driver circuit 122 is provided for the light source 130 embodied as a light-emitting diode.
  • a microprocessor is attached to the circuit board, which serves as an evaluation unit 125 for the output signals provided by the individual LEDs.
  • a mechanical support 132 is further attached, in which the light-emitting diode 130 by means of a simple Einklippvorgangs is fixed.
  • the light-emitting diode is thus precisely captured in the holder 132. As a result, a high quality of the beam alignment can be ensured.
  • a holder 143 is provided, which is also secured to the circuit board 120 and which holds a mirror formed secondary reflector 142 in a fixed spatial position.
  • the secondary reflector 142 is disposed in the vicinity of the photodiode 140 and serves to image or the beam deflection of the measurement light 135 received by the photodiode 140.
  • the secondary reflector 142 has a faceted shape, wherein each one facet of one of the photodiodes 140 is assigned. In the cross-sectional representation of FIG. 1 is only one facet to recognize.
  • the secondary reflector 142 may be a planar or a hyperbolic reflector.
  • a hyperbolic reflector By means of a hyperbolic reflector, even with a slight optical misalignment it can be ensured that the light spot projected from the light-emitting diode 130 onto the side wall or onto the primary reflector is reliably imaged onto the photodiode 140. Of course, this only applies to that part of the light spot which is associated with a partial beam of the measuring light 135 and thus with one of the photodiode 140.
  • the smoke detector 100 also has a Fresnel optics 115.
  • the Fresnel optical system 115 serves for the efficient imaging of the measuring light onto the photodiode 140.
  • the Fresnel optical system 115 is formed integrally with the housing 110. To minimize the risk of contamination for the Fresnel optics 115, this is formed on the inner wall of the housing 110.
  • the optical cover of the smoke detector 100 is thus part of the outer housing.
  • the optical cover has the material polycarbonate.
  • the optical cover has a dark infrared filter coloring.
  • FIG. 1b shows the smoke detector 100 in a highly simplified plan view.
  • the four double beams which (a) from the light source 130, not shown in the radial outward along a respective beam axis 135a emitted and (b) detected after an at least partial reflection on a side wall of a space to be monitored by two photodiodes 140 become.
  • Each double beam has a first spatial part 136a of the measuring light 135 and a second spatial part 136b of the measuring light 135.
  • the first spatial part is also referred to as the first partial beam 136a.
  • the second spatial part is also referred to as the second partial beam 136b.
  • a photodiode detects in each case a part of the measuring light or a partial beam of the double beam.
  • each received double beam Fresnel optics 115 is assigned. This can be optimally adapted to the shape of the double jet and / or to the shape of the housing 110.
  • the optics and the sensor technology of the smoke detector 100 will be explained in more detail below. Even with the use of four double beams, an implementation of the present invention by means of a respective transmitter-receiver pair for each signal path or for each sub-beam would be very expensive. If in each case a complete transmitter-receiver pair were used, then the smoke detector 100 would require a total of eight light sources and eight photodiodes. Therefore, it is advantageous, in particular for cost reasons, that only one light source is present in the smoke detector 100.
  • a useful effective opening angle of the partial beams 136a, 136b depends on the tolerances that can be achieved. So that no adjustments are necessary, taking into account all mechanical tolerances, the light spot of the respective light-emitting diode 130 in the far region should be slightly larger than the image of the respective photodiode projected onto the scattering background.
  • the term far field is understood to mean the respective backscattering background and in particular an opposite wall. Due to the principle of reversibility of the beam path, the image of the respective photodiode determines the spatial detection range of the respective photodiode.
  • the described concept of the double beams provides that the two adjacent photodiodes define, generate or define the double beams via the reflector and the Fresnel lens.
  • the first round illumination spot on the wall of a room to be monitored could not be optimally approximated to a rectangular shape resulting from two partial beams located side by side.
  • the entire electronics of the smoke detector 100 may be constructed on the single circuit board 120. So that the light-emitting diodes 130 can be easily used with the holder 132 in the beam axes 135a on the one side and the photodiodes 140 by means of SMD technology on the other side, a 90 ° beam deflection is advantageous for the measurement light 135 received by the photodiodes 140.
  • each pair of receivers is assigned a receiving optics on the receiving side, which images the two partial beams on two directly adjacent photodiodes as a receiver.
  • the receiver electronics must be made double.
  • the use of a time division multiplex Although it is possible to separate the reflections from both partial beams, this does not currently appear to be advantageous due to the expected higher power consumption. Namely, the transmission power would have to be applied twice as much as the solution described. Even if a single photodiode would be cheaper due to the imaging geometry, beam pairs are significantly more advantageous for detection and signal processing.
  • the light source can emit a pulsed measuring light. By measuring the light transit time between the light source and at least one photodetector, a distance measurement between the light source and the primary reflector can be performed.
  • signal characteristics may be (a) the signal levels, (b) the behavior of signal rise and / or fall, (c) cross-correlation in a double beam, (d) cross-correlation between different beam pairs, (e) distance of the optical path , (f) correlation between distance of the optical path and signal rise and / or fall, (g) correlation between the distance of the optical path for different partial beams and / or different double beams.
  • the correlation of the measuring light intensity of the different pairs of beams scattered back from the opposite wall is evaluated as a fundamental criterion.
  • at least one further adjacent beam pair also detect smoke development.
  • the resulting signal curve will be correlated less strongly than within a double-beam pair.
  • an essential criterion in the detection of smoke is that the distance does not change.
  • the measuring light will continue to be reflected essentially on the fixed background.
  • the signal properties described above and a distance evaluation, together with their many dependencies, can provide a dense network of decision bases. These can be used for better detection properties and for increased suppression of disturbances.
  • the partial beams or beam pairs of the smoke detector should not protrude into the zone in which people move. Movements of persons from smoke to discriminate is possible in principle. However, this typically requires a high computational effort.
  • the smoke detection can be performed by means of a variable sampling rate.
  • the smoke detector is initially operated with a low repetition rate and / or with a low light intensity. Only when a suitable preprocessing of the measurement signals obtained provides an indication of the formation of smoke, then the repetition rate and / or the current for the LEDs are increased and carried out an accurate signal evaluation.
  • FIG. 2 shows a smoke detector 200 mounted in the corner of a room 260 to be monitored.
  • the upper part of FIG. 2 shows the optical paths in a plan view parallel to an xy plane.
  • the lower part of FIG. 2 shows the beam paths in a side view parallel to an xz or yz plane.
  • the smoke detector 200 has four double beams for smoke detection.
  • the corresponding measuring light 235 of the double beams respectively runs along a beam axis 235a.
  • the space 260 to be monitored has four side walls 261 and 262.
  • the measuring light 235 impinges on the two side walls 262 and is at least partially reflected back to the smoke detector 200.
  • the side walls 262 thus represent the partially scattering article or the primary reflector.
  • all the rays of the measuring light 235 run in a horizontal direction substantially parallel to a ceiling 265 and to a floor 266 of the space 260 to be monitored. This is in the lower part of FIG. 2 clarified.
  • the smoke detector can also use more than four double beams for smoke detection.
  • the smoke detector 200 described is a so-called extinction detector. In contrast to known based on the principle of extinction smoke detectors, however, no special reflectors are provided in the smoke detector 200. Rather, any object which has at least a certain reflection at least for the respective spectral range of the measuring light is sufficient. In the present case, this means that at least some reflection from the surrounding walls 262 is assumed.
  • FIG. 3 Figure 4 shows a system with four smoke detectors 300 which each use four double beams for smoke detection.
  • the upper part of FIG. 3 shows the beam paths of the double beams in a plan view parallel to an xy plane.
  • the lower part of FIG. 3 shows the beam paths in a side view parallel to an xz or yz plane.
  • the four smoke detectors 300 are arranged in the middle of a room 360 to be monitored in such a way that the total of 16 double beams extend in a star shape radially outward from the center of the room.
  • a fan beam is formed in the smoke detector 300.
  • smoke detectors shown this beam fan is not horizontal over the room. Rather, starting from a height near the ceiling 365 of the room 360 in the center of the room, the fan-beam is inclined slightly downwards in the direction of the floor 366. However, the inclination should be chosen so moderately that the rays of the measuring light do not protrude as far as possible into the space typically used by people.
  • FIG. 4 shows in a perspective view the assembly of in FIG. 1 illustrated smoke detector, which is now designated by the reference numeral 400.
  • the smoke detector 400 which has a housing 410 with a total of four integrated Fresnel optics 415, is attached to a side wall of a space to be monitored.
  • the housing 410 is designed such that for horizontal beam arrangements mounting without a holder flat on the side wall is possible.
  • FIG. 5 shows in a perspective view the assembly of in FIG. 1 illustrated smoke detector, which is now designated by the reference numeral 500.
  • the smoke detector 500 which has a housing 510, is disposed in a corner of a room to be monitored. How out FIG. 5 can be seen, the housing 510 is designed such that for horizontal beam arrangements, a mounting without a holder in a corner of the room is possible.
  • FIG. 6 shows a schematic representation of a smoke detector 600, which can be attached by means of a holder 618, for example, on a side wall of a space to be monitored.
  • the smoke detector 600 has a housing 610.
  • the entire smoke detector 600 is pivotally mounted on the holder 618 about a rotation axis 618a.
  • the smoke detector 600 can be easily adjusted with different inclination angles of the measuring light. This means that the detector axis can be tilted down or up.
  • This application describes a novel linear smoke detector. This can monitor with several double beams a 90 ° segment, ie a segment, with an opening angle between 80 ° and 100 °, with a total of up to 20m x 20m edge length. Thus, a higher detection reliability is possible in comparison to a single-beam smoke detector with increased false alarm immunity.
  • linear surface protection can be realized inexpensively. This results in one of the lower number of mechanical parts and on the other from the omission of optical elements such as lenses. Furthermore, the structure of the smoke detector described is much simpler than in known linear smoke detectors. An adjustment of the optical components is not required. This makes assembly easy and reduces production costs considerably.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Computer Security & Cryptography (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Business, Economics & Management (AREA)
  • Emergency Management (AREA)
  • Fire-Detection Mechanisms (AREA)
  • Investigating Or Analysing Materials By Optical Means (AREA)
EP08101741A 2008-02-19 2008-02-19 Détecteur de fumée optique linéaire doté de plusieurs rayons partiels Withdrawn EP2093731A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP08101741A EP2093731A1 (fr) 2008-02-19 2008-02-19 Détecteur de fumée optique linéaire doté de plusieurs rayons partiels

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EP08101741A EP2093731A1 (fr) 2008-02-19 2008-02-19 Détecteur de fumée optique linéaire doté de plusieurs rayons partiels

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EP2093731A1 true EP2093731A1 (fr) 2009-08-26

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Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102012022051A1 (de) * 2012-11-09 2014-05-15 Kidde-Deugra Brandschutzsysteme Gmbh Optische Detektoreinrichtung zur Branderkennung
EP2908297A1 (fr) * 2014-02-12 2015-08-19 Robert Bosch Gmbh Dispositif linéaire d'alerte d'incendie et procédé de fonctionnement du dispositif linéaire d'alerte d'incendie
EP3009999A1 (fr) * 2014-10-16 2016-04-20 Société d'Etude et de Fabrication Industrielle Detecteur lineaire de fumee encastre
US10989368B2 (en) 2017-04-13 2021-04-27 Carrier Corporation Notification device for a surface of a building interior
CN113168752A (zh) * 2018-10-15 2021-07-23 庞巴迪运输有限公司 用于分段探测烟雾的烟雾探测器和具有烟雾探测器的车辆
CN113939727A (zh) * 2019-06-11 2022-01-14 ams有限公司 光学微粒传感器
CN115240358A (zh) * 2022-05-25 2022-10-25 中国船舶重工集团公司第七0三研究所 一种用于烟雾浓度检测的吸气式感烟探测结构

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1439325A (en) * 1972-05-06 1976-06-16 Kgm Electronics Ltd Alarm detectors
WO1982003487A1 (fr) * 1981-03-25 1982-10-14 Telefon Ab L M Ericsson Detecteur optique de feu
EP0472039A2 (fr) * 1990-08-23 1992-02-26 Nohmi Bosai Ltd. Procédé et dispositif pour la détection d'incendie
WO2001067415A1 (fr) * 2000-03-09 2001-09-13 Robert Bosch Gmbh Detecteur d'incendie imageur
WO2002069297A1 (fr) * 2001-02-27 2002-09-06 Robert Bosch Gmbh Procede de reconnaissance d'incendie

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1439325A (en) * 1972-05-06 1976-06-16 Kgm Electronics Ltd Alarm detectors
WO1982003487A1 (fr) * 1981-03-25 1982-10-14 Telefon Ab L M Ericsson Detecteur optique de feu
EP0472039A2 (fr) * 1990-08-23 1992-02-26 Nohmi Bosai Ltd. Procédé et dispositif pour la détection d'incendie
WO2001067415A1 (fr) * 2000-03-09 2001-09-13 Robert Bosch Gmbh Detecteur d'incendie imageur
WO2002069297A1 (fr) * 2001-02-27 2002-09-06 Robert Bosch Gmbh Procede de reconnaissance d'incendie

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102012022051A1 (de) * 2012-11-09 2014-05-15 Kidde-Deugra Brandschutzsysteme Gmbh Optische Detektoreinrichtung zur Branderkennung
EP2908297A1 (fr) * 2014-02-12 2015-08-19 Robert Bosch Gmbh Dispositif linéaire d'alerte d'incendie et procédé de fonctionnement du dispositif linéaire d'alerte d'incendie
EP3009999A1 (fr) * 2014-10-16 2016-04-20 Société d'Etude et de Fabrication Industrielle Detecteur lineaire de fumee encastre
FR3027438A1 (fr) * 2014-10-16 2016-04-22 Soc D'etude Et De Fabrication Ind Detecteur lineaire de fumee encastre.
US10989368B2 (en) 2017-04-13 2021-04-27 Carrier Corporation Notification device for a surface of a building interior
CN113168752A (zh) * 2018-10-15 2021-07-23 庞巴迪运输有限公司 用于分段探测烟雾的烟雾探测器和具有烟雾探测器的车辆
CN113168752B (zh) * 2018-10-15 2023-09-22 庞巴迪运输有限公司 用于分段探测烟雾的烟雾探测器和具有烟雾探测器的车辆
CN113939727A (zh) * 2019-06-11 2022-01-14 ams有限公司 光学微粒传感器
CN115240358A (zh) * 2022-05-25 2022-10-25 中国船舶重工集团公司第七0三研究所 一种用于烟雾浓度检测的吸气式感烟探测结构

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