FR2811456A1 - Equipment for detecting start of fires in protected zone, comprises array of infra red detectors which are connected to microprocessor and visual warning units such as smoke generators or lights - Google Patents

Abstract

An array of infrared detectors (2) is deployed over an area to be protected and connected by wire or radio to a microprocessor (4) which also receives time of day data (5). When the microprocessor detects danger two visual alarms (3a,3b) are operated. The first alarm (3a) is a smoke generator of normal design and the second alarm (3b) is a high powered coloured light which may be pulsed

Description

The technical field of the invention is that of devices allowing

  detect the start of fires in an area, especially in a wooded area. Fire, especially in forest fires, is a scourge that is difficult to fight effectively.

  One of the essential conditions for an effective fight against these fires is their early detection.

  It is thus known to provide surveillance towers with observers near the forest massifs

humans or cameras.

  However, this observation technique is insufficient because fires generally start at ground level and

  are then invisible from a distance. When the fire and smoke were large enough to be visible above the tops of the trees, the intensity of the fire also became too great for it to be quickly stopped.

  Furthermore, the forest areas located in difficult-to-access areas (mountains) do not lend themselves to

  direct observation and the installation of observation towers20 is difficult.

  Patent WO91 / 09390 proposes to have on-site detection means comprising TV cameras and sensors

  infrared placed on a motorized platform. These means are linked by a radio transmitter to a remote alarm control center25.

  Such a solution is expensive. In addition, it is difficult to use in massifs located on difficult terrain. The need to monitor large areas is not limited to wooded areas. It may also be necessary to monitor the fire risk for areas at a lower cost

  large areas, such as cultivated areas, industrial areas, depots. ..

  It is the object of the invention to propose a device

  allowing to overcome such drawbacks.

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  Thus, the invention proposes a device allowing surveillance at low cost of large areas. Thus, the subject of the invention is a device making it possible to detect the start of fires in an area, in particular wooded area, and comprising at least one detector of

  heat and / or infrared, characterized in that the detector is connected to at least one visual signaling means which it triggers when the heat and / or infrared radiation level exceeds a given threshold.

  Advantageously, this device comprises several detectors and several visual signaling means

  distributed in the area to be monitored according to a monitoring mesh. 15 Each visual signaling means may be connected to at least two detectors.

  Preferably, each detector may be placed at a distance from the visual signaling means associated with it

  and connected to it by a wire or radio link means.20 The visual signaling means may include at least one smoke generator.

  The visual signaling means may include at least one light generator.

  According to a variant, remote observation means may be provided making it possible to identify the appearance of a light or smoke signal supplied by the means of

  visual signaling. These observation means may include at least one camera fixed on an observation pylon.

  These remote observation means may include at least one alarm transmitter linked by radio to a

  alarm management center. The invention will be better understood on reading the following description of different embodiments,

  description made with reference to the accompanying drawings and in which:

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  - Figure 1 shows a block diagram of a device according to a first embodiment of the invention, - Figure 2 shows a block diagram of a device according to a second embodiment of the invention, - Figure 3 represents in the form of a block diagram a device according to a third embodiment of the invention, 10 - Figure 4 schematically represents a smoke generator as well as a variant of the device according to the invention, - Figure 5 is an example of layout using a device according to the invention for monitoring a forest, - Figure 6 is a layout diagram of the device according to the invention for monitoring a forest, - Figure 7 is a layout diagram of the device according to the invention for monitoring an industrial area. 20 Referring to FIG. 1, a device for detecting the initiation of fire 1 according to a first embodiment of the invention comprises a u at least one heat and / or infrared detector 2, connected to at least one visual signaling means 3a, 3b.25 The detector (s) 2 may be infrared sensors or any other means sensitive to an increase in the

  temperature (thermocouple, cell containing an expandable gas, etc.). The signaling means 3a is a smoke generator.

  It will preferably include a pyrotechnic smoke generator. Such smoke generators are well known to those skilled in the art. It is also possible to produce a "chemical" smoke generator in which the smoke results from the triggering

  a chemical reaction (for example the reaction of titanium tetrachloride with water).

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  The advantage of pyrotechnic generators is their compactness for a given smoke generation capacity.

  The signaling means 3b is a generator of high-power light signals, such as a flash lamp of a specific color or a bright and high-power light projector. Such generators are also well known to those skilled in the art. They most often use a lamp

  strong power. They can also be made up of laser devices.

  According to this first embodiment, the heat detectors 2 are connected to the signaling means 3a, 3b by

  via a trigger means 4 for signaling means. 15 This triggering means may be constituted by an electronic circuit comprising for example a micro-

  processor. This circuit 4 can advantageously receive the signals supplied by a day / night sensor 5, constituted for example by a photoelectric cell arranged so as to receive the ambient lighting.

  The trigger means 4 can then activate the signaling means 3a or 3b most suitable for the instant considered. He will order the smoke generator 3a the day by

  example and the light generator 3b at night or in foggy weather.

  According to the invention, the heat detectors are distributed in the area considered so as to be able to

  detect a possible rise in temperature or infrared radiation following the start of a fire.

  These detectors will for example be arranged so as to be able to monitor the temperature or the heat at ground level. When the level of heat and / or infrared radiation exceeds a given threshold, the triggering means 35 causes the initiation of the smoke generator 3a and / or of the light generator 3b. These will be arranged so that the visual signal provided is visible from a distance. We could for example, in a forest, fix these devices in

  height, on masts or on top of trees.

  Thanks to the invention, the start of the fire is thus detected very early and the alert information is transmitted without delay. Indeed, the detection is carried out in the vicinity of the points where there is a risk of appearing the fire and the transmission of the visual signal is carried out at a location where this signal

is more particularly visible.

  This separates the detection and signaling functions. A fire is signaled at a distance by a visual signal of substantial amplitude (colored smoke column for example) while it is still only at the very beginning of its start and generates little smoke itself. Such a device can obviously be implemented for the surveillance of a zone other than a forest zone. The same guiding principles will be used. The detectors will be placed in the vicinity of the areas where the risk of fire starting exists (inside buildings or in the vicinity of these) and the signaling means will be placed at a point (preferably in height) where the signal will be easily visible from afar. Another advantage of the invention is that the signaling is ensured whatever the visibility conditions, day and night thanks to the possible association of a smoke generator and a light generator. However, it is possible to use only one of these signaling means, preferably the smoke signal. As a variant, it is possible to supplement the visual signaling means by adding an acoustic generator.

(loudspeaker, siren).

  FIG. 2 shows a second embodiment of a device for detecting the triggering of a fire 1 according to the invention. This mode differs from the previous one in that the infrared detectors 2 and the means of connection are directly connected

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  visual signaling 3a, 3b. These latter means will integrate

  each an energy source as well as the circuits making it possible to interpret the signals supplied by the infrared detectors 2. The triggering of the smoke generator 3a as well as of the light generator 3b will occur simultaneously whatever the visibility conditions.

  The different detectors 2 can be connected to the signaling means 3a / 3b by wired links or else by wireless (radio) links. FIG. 3 shows such an embodiment in which the detectors 2 are distributed over the area which have a

  transmitter device 6 (radio for example) which dialogs with a receiver 7 connected to each signaling means 3a or 3b.

  Preferably, the radio links between the detectors 2 and the signaling means 3a / 3b will be carried out in a coded manner in order to avoid nuisance trips and false alarms. Each detector 2 and each signaling means will be completely autonomous and will include its power source and its electronic signal processing circuits. This embodiment, by removing the wired links, makes it easier to set up in the field

  detectors and signaling means.

  According to an alternative embodiment, it is advantageously possible to provide remote observation means 8

  to identify the appearance of a light or smoke signal provided by the visual signaling means30 3a / 3b.

  These means may be constituted by at least one observation pylon 9 carrying at least one camera 10. The camera will advantageously be fixed on a rotating platform 11. Electronic means 12 for analyzing the signals35 supplied by the camera will be provided as well that transmission means 13 connected by radio to a central management

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  alarms 14 provided with an antenna 14a and located at a distance from the area, for example at an intervention station. The advantage of such a variant is that the observation means 8 make it possible to immediately detect the appearance of the visual signals (smoke or light) emitted by the signaling means 3a / 3b and ensure the immediate transmission of the alarm to intervention forces. Due to the presence of signaling means providing a visual signal of sufficient intensity, the contrast of these signals with the ambient space is high and the observation cameras as well as the signal analysis means can easily spot them ( we can for example use colored smoke bombs). It is therefore possible, thanks to the invention, to implement

  observation means 8 of simpler technology than the known means sometimes implementing expert systems.

  In addition, the visual signal emitted remains visible to all walkers present near the area. The latter can therefore also transmit an alarm thus remedying20 a possible failure of the observation means and they can take all protective measures at their level.

(evacuation of the area ...).

  FIG. 4 schematically represents a smoke generator 3a which is directly connected (by wire or by radio)

to an infrared detector 2.

  This generator comprises a housing 15, made for example of metal, and comprising a housing inside which are arranged tablets 16 of a smoke composition. The housing is sealed off by a metal cover 30, glued, screwed or welded to the housing 15. The cover 17 carries a pyrotechnic igniter 18 intended to

  initiate the composition which is connected to the detector 2 possibly via a triggering means (not shown).

  The igniter is linked to the lid by a cover

  ejectable 32 in thin sheet glued to cover 17.

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  During the initiation of the composition, the cover 32 is ejected and the hole 33 provided in the cover 17 is cleared allowing the passage of smoke. A free space 34 between the composition and the cover 17 makes it possible to maintain a certain pressure of the gases generated above the composition, which promotes combustion.

  The housing 15 will be provided with means (not shown) allowing it to be fixed to the area (on a tree or a mast).

  Smoke compositions, colored or not, are well known to those skilled in the art. They generally include an oxidant (such as a chlorate or a perchlorate) associated with a reducing agent such as lactose. We can possibly color the smoke by adding an organic dye (rhodamine, auramine ...)

or mineral (metal oxide).

  Figure 5 is an example of implementation of a device according to the invention for monitoring a forest.

  The detectors, for example infrared detectors 2, are arranged in the vicinity of the ground 19. A detector 2 can be carried by a stake 20 driven into the ground. It can be attached to a terminal

  21 sealed in the ground. They can also be fixed to a shaft by straps 22 or else by screws.

  The signaling means 3a or 3b will be fixed at a distance from the ground of the order of 10 to 20 meters. Such means may be attached to a shaft 23 at the level of the high branches, for example with straps 24. It may also be arranged at the top of a mat 25 secured to the ground. A smoke generator 3a and a light generator 3b.30 will advantageously be fixed at the top of each mast. The detectors 2 shown here as well as the signaling means are connected by short radio links.

  range (<100 m). Figure 6 shows a layout diagram of such a device for monitoring a forest.

  The forest is here represented by a rectangle 26 and the trees are not drawn for the sake of clarity.

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  Detectors 2 are regularly distributed in the forest according to a square mesh network comprising lines 27a, 27b, 27c, 27d parallel to each other and lines 28a, 28b, 28c and 28d perpendicular to the lines 27. The mesh may have dimensions of around 40 mx 40 m. A detector 2 is arranged substantially at each intersection of lines 27 and 28. The forest thus comprises n detectors 2.1, 2.2, 2.3, ......., 2.n. Signaling means 3a or 3b is placed substantially in the center of each elementary square of the network. We have shown here smoke generators 3a each arranged at the top of a mast 25. The drill thus comprises a network of n signaling means 3a.1, 3a.2, 3a.3, ......... .., 3a.n. The forest 26 is surrounded here by distant observation means 8a, 8b, 8c and 8d. These means each include an observation pylon 9 carrying a camera 10. Four pylons are shown here, but practically two pylons would be sufficient. The number of pylons will be multiplied as a function of the dimensions of the area to be monitored.20 The observation means 8 are connected by radio to an alarm management center 14 located at an emergency response station. Such a network of the forest by detectors and signaling means makes it possible to effectively locate the

place of departure of the fire.

  In fact each detector 2 will be programmed so that it can only trigger the four signaling means which are closest to it. Such an arrangement will be easily obtained by coding the signals.

  of transmission between detectors and signaling means.

  Furthermore, its detection area A will have a radius substantially equal to the half side of a mesh of the network. So

  the detection areas Ai of each detector 2.i are separated.35 Thus a start of fire 29 located in the detection area A.7 of detector 2.7 will only be detected by the latter.

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  It will then trigger the signaling means which are attached to it, ie here the smoke generators 3a.3, 3a.4, 3a.7 and 3a. 8. Four columns of smoke will be emitted which will be easily identified and located by means of observation

8a, 8b, 8c and 8d.

  Each observation means provides the four directions of observation corresponding respectively to each column of smoke. The intersection of the directions provided by the means of observation of at least two pylons makes it possible to determine the coordinates in the forest 26 of the four signaling means which have been activated. Thus the alarm management center 14 immediately receives an approximate value of the point coordinates

  29 starting fire detected (to the dimensions of the mesh of the surveillance network close).

  Due to the non-overlapping of the surveillance areas Ai, it is possible to complete the mesh shown in the

  FIG. 6 by other detectors 2j arranged in the vicinity of the ground and substantially at the level of the mats 25 (here only a detector 2j is represented at the level of the generator 3a.2).

  These detectors will have a radius of effectiveness of the same order as that of the other detectors and they will be configured so as to be able to cause only the triggering of the signaling means carried by their own mast. They make it possible to complete the monitoring of the forest area 26. A fire trigger 30 detected by the detector 2j will cause the emission of a single signal whose location will be easily ensured by the observation means 8.30 It is of course possible to vary the shape of the mesh of the forest area by providing a greater or lesser number of detectors having a variable range. We could for example only provide detectors 2j integral with the detection masts (or trees carrying the signaling means). Different detectors can be associated with an electronic triggering means analyzing the signals supplied by the detectors and determining the signaling means or means closest to the start of the fire. In all cases, and depending on the risk of fire in the area considered, the automatic detection provided by the observation means may be omitted and replaced by the only visual localization provided by observers or by walkers. FIG. 7 represents a layout diagram of the

  device according to the invention for monitoring an industrial area.

  This zone includes different buildings or storage zones 31a, 31b, 31c ...... 31h. At each building is

  associated with a signaling means 3a and / or 3b (3a.1 ... 3a.8) 15 which is shown here integral with a mast 25 but which could simply be fixed to the building considered.

  Heat and / or flame detectors 2 (2.1 .... 2.8) (the precise location of which cannot be shown here, taking into account the scale of the figure) will be placed inside and / or exterior of buildings 31. The detectors will be connected to a triggering means which will activate the signaling means associated with the building as soon as a fire starts. Thus the device according to the invention makes it possible to signal

  very quickly outside a fire which is still only minimal.

  Observation means 8a, 8b may be arranged in the vicinity or in the area to be monitored. They will allow, as in the previous example, to quickly locate the start-up of a signaling means 3a / 3b and will transmit the coordinates to the alarm management center 14

  approximate of the starting point of fire thus detected.

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Claims (5)

  1- Device (1) for detecting the start of fires in an area, in particular wooded area, and comprising at least one detector (2) of heat and / or infrared, characterized in that the detector (2) is connected at least one visual signaling means (3a, 3b) which it triggers when the level of heat and / or infrared radiation exceeds a given threshold.   2- Device according to claim 1, characterized in that it comprises several detectors (2) and several visual signaling means (3a, 3b) distributed in the area to   monitor using a monitoring mesh.   3- Device according to one of claims 1 or 2,   characterized in that each means (3a, 3b) of visual signaling is connected to at least two detectors (2).   4- Device according to one of claims 1 to 3, characterized in that each detector (2) is arranged at   distance from the visual signaling means (3a, 3b) associated with it and connected to it by a wired or radio link means.   - Device according to one of claims 1 to 4, characterized in that the signaling means (3a, 3b)   visual device include at least one smoke generator. 25 6- Device according to one of claims 1 to 5, characterized in that the signaling means (3a, 3b)   visual include at least one light generator. 7- Device according to one of claims 1 to 6, characterized in that remote observation means (8)   are provided to identify the appearance of a light or smoke signal provided by the means (3a, 3b) of visual signaling. 8A device according to claim 7, characterized in that the observation means (8) comprise at least one   camera (10) fixed on an observation pylon (9). 13 2811456   9- Device according to claim 8, characterized in that the remote observation means (8) comprise at least one alarm transmitter, (13) connected by radio to   an alarm management center (14).