EP1300816A1 - Method and system to detect fires in enclosed spaces - Google Patents

Abstract

The method involves passing electromagnetic radiation (3) over a defined path through a monitored space and to at least one electrooptical device (5,6) for detecting optical signals. The signals detected by the electrooptical device are compared with stored signals to detect variations in the shape and/or type an/or intensity and/or position of the radiation and to generate an alarm signal if at least one defined threshold is reached or transited. <??>AN Independent claim is also included for the following: a system for detecting fires in rooms.

Description

The present invention relates to a method and a system for recognition of fires in rooms, in particular freight spaces, sales rooms and the like, wherein electromagnetic radiation over a predetermined Route passed through a room to be monitored and at least in the process an electro-optical device for detecting optical signals becomes.

Such methods and systems are usually used in alarm reporting systems used to detect and display fires in rooms in order to target Initiate protective and / or auxiliary measures. Because protection and / or Aid measures are extremely costly to the detection of smoke increased reliability requirements as part of fire detection, especially in the area of cargo transportation by aircraft, where at False alarm messages due to protective and / or countermeasures in the cargo hold existing goods damaged or destroyed by fire fighting measures can become and sometimes unnecessary landing maneuvers. About that it is also necessary to detect smoke in rooms as quickly as possible.

Fire sensors conventionally used in the prior art are based on their Functionality primarily on the detection of smoke. This is about a usually short distance the occurrence of through the presence of Scattered light caused by smoke particles detected. Requirement for a detection is a sufficiently high concentration of smoke particles at the location of the Scattered light detection fire sensor to trigger a threshold to exceed a fire report, especially since the so far in Fire detection systems used sensors essentially only one enable punctiform acquisition. Due to the generally short On the one hand, the fire detection sensitivity must be high, on the other hand there must be a sufficient level difference to the resting behavior, i.e. to those of that Fire sensor in the smoke and / or fire-free state, signals are present, to avoid false alarms. In practice, false alarms often occur, and that Response speed to smoke due to fire is very fluctuating and does not meet the increased reliability requirements.

In view of this prior art, the object of the invention is to provide a method and a system of the type mentioned at the outset which enable fire detection in rooms, in particular cargo holds, sales rooms and the like, to be carried out extremely reliably and quickly and are less susceptible to faults.

The method, the object is achieved in that the part of a communicatively connected to the electro-optical device computing device based at least on a comparison of the electro-optical device detected signals of the electromagnetic radiation with stored signals of the electromagnetic radiation deviations of form and / or type and / or intensity and / or the position of the electromagnetic radiation is determined and an alarm signal is generated when it reaches, falls below or exceeds at least one predeterminable threshold value.

By the comparison according to the invention of the electro-optical device detected signals of electromagnetic radiation, preferably one Light beam with signals stored by the computing device electromagnetic radiation with regard to deviations in shape, type, The intensity and / or location of the electromagnetic radiation is smoke in the too monitoring room can be quickly detected with high reliability.

The invention is based on the finding that smoke is characteristic optical Features that can be used to detect smoke. This is how light becomes scattered diffusely on smoke particles, absorbed by smoke particles and by Multiple reflections on smoke particles depolarized. Smoke allows next to the Detection of direct radiation from the source of the fire, in addition to detection ascending heat streaks. The effects of a source of fire in The form of smoke thus enables extensive fire detection options.

On aerosols caused by combustion processes, smoke particles in the Ambient air, the light beam is scattered and reflected several times. Thereby the cross section of the light beam is enlarged. The cross-sectional enlargement the light beam is advantageously based on the comparison by the Computing device detected and when a certain one is exceeded Threshold value generates an alarm signal.

Smoke particles in the air caused by combustion processes bring you Light absorption with it, which leads to a weakening of the luminance of the light beam leads. This weakening is advantageously detected and if it is undershot a certain threshold value on the part of the computing device generates an alarm signal.

A band absorption given by gaseous combustion products in the form of particles in the air, for example carbon monoxide (CO) or carbon dioxide (CO ₂ ), is advantageously detected and an alarm signal is generated when a band absorption is detected. In the case of band absorption, individual wavelengths of the light beam that are characteristic of the particulate combustion products in the air are absorbed. Electromagnetic radiation of this wavelength is then missing in the detection by means of the electro-optical device. This lack is detected on the basis of the comparison. The missing wavelength provides information about the specific material properties of the combustion products in the air leading to band absorption and thus information about a possible fire. In addition, the burning substance, the cause of the fire or the like can advantageously be determined on the basis of the detected band absorption.

In a further advantageous embodiment of the invention, combustion processes Smoke particles in the air cause depolarization of the light beam is detected and if a threshold value is exceeded on the part the computing device generates an alarm signal. Advantageously, the of light beam generated by a light source has a defined polarization direction, which is preferably generated with a polarization filter. On the part of electro-optical device is advantageously an analyzer with a Polarization direction of the light beam crossed polarization direction arranged. In the absence of smoke particles depolarizing in the air is crossed by the electro-optical device due to the Polarization direction of analyzer and light beam or polarization filter none Signal detected because the polarized light beam is blocked by the analyzer. When the light beam is depolarized by combustion products in the air the direction of polarization of the light beam partially rotated, so that this in the Direction of polarization rotated part of the light beam in its direction of polarization is no longer crossed to the polarization direction of the analyzer and this therefore can happen partially or completely. This depolarized portion of the Light beam is detected by the electro-optical device and based on the Comparison if the threshold is exceeded by the Computer generates an alarm signal. In addition, based on the the depolarization given change in direction of the polarization direction of the Light beam further information about the smoke particle causing Fire can be determined, for example, the cause of the smoke particles generating burning substance, or the like.

In a further advantageous embodiment of the invention, an open fire due to the presence of electromagnetic radiation of certain wavelengths, preferably recognized in the infrared (IR) and / or ultraviolet (UV) range. The electro-optical device is advantageously in the region of the respective device Wavelength sensitive.

A fire is advantageously detected by detection of z. B. one Fire streaks caused by heat development are detected. The beam of light is distracted from the route by streaks. This distraction is based on the comparison is detected by the computing device and an alarm signal generated when a certain threshold is reached, fallen below or is exceeded. The deflection is advantageously a change in the Intensity of the light beam can be detected, which when reaching, falling below or Exceeding a certain threshold for alarm signal generation on the part leads the computing device. The streak detection is advantageously carried out in a brightfield or darkfield arrangement.

The light beam is advantageously a beam of collimated electromagnetic Radiation, the beam being collimated such that the light is parallel. The light beam advantageously has a defined polarization direction. The direction of vibration of the individual light wave packets of the light beam is thereby firmly defined. In a further advantageous embodiment of the invention, the Light beam coherent, i.e. Light of a uniform wavelength or one certain wavelength range. In a particularly preferred embodiment According to the invention, the light beam is generated by a laser, a light source with high coherence the collimated light beams with defined polarization direction provides.

In a particularly preferred embodiment of the invention, the light beam pulsed. So when synchronizing the pulsed light beam with the electro-optical device and the computing device interference and / or Switch off the effects of extraneous light.

According to a further particularly advantageous embodiment of the invention as an electro-optical device in addition to video cameras, which signals the Capture light beam in the form of images by the computing device stored, also radiation sensors for defined wavelengths or defined wavelength ranges, preferably radiation sensors for electromagnetic Radiation used in the IR and / or UV range.

According to a further particularly advantageous embodiment of the invention are several electro-optical devices on the part of the computing device Acquisition of signals of the light beam combined in terms of data technology, preferably such that those detected by the electro-optical devices Signals combined with each other and on the part of the computing device stored empirical records about smoke upon reaching, exceeding or falling below a certain threshold value generates an alarm signal becomes.

Fig. 1

in einer schematischen Darstellung den prinzipiellen Aufbau eines erfindungsgemäßen Systems zur Durchführung des erfindungsgemäßen Verfahrens;

Fig. 2

in einer schematischen Darstellung eine Anordnung zur erfindungsgemäßen Aufweitung des Lichtstrahls;

Fig. 3

in einer schematischen Darstellung eine Anordnung zur erfindungsgemäßen Schlierenerkennung und

Fig. 4

in einer schematischen Darstellung den prinzipiellen Ablauf des erfindungsgemäßen Verfahrens.

Further details, features and advantages of the invention are explained in more detail below with reference to the exemplary embodiments shown in the figures. Show:

Fig. 1

a schematic representation of the basic structure of a system according to the invention for performing the method according to the invention;

Fig. 2

a schematic representation of an arrangement for expanding the light beam according to the invention;

Fig. 3

in a schematic representation an arrangement for streak detection according to the invention and

Fig. 4

the basic sequence of the method according to the invention in a schematic representation.

Fig. 1 shows a schematic representation of a top view of one monitoring cargo hold 1. The light source 2 generates a collimated light beam 3, 3 'with a fixed direction of polarization, which according to deflection mirror 4 Requirement is passed through the cargo hold 3 over a predetermined distance. The path of the light beam 3, 3 'is individual via the deflecting mirror 4 the needs of the cargo hold 1 to be monitored with regard to spatial Customizable conditions and type and position of the cargo in the cargo hold 1. present the path of the light beam 3, 3 'advantageously runs in the region of Ceiling of the cargo hold 1. Usually rising in the event of fire and thus smoke reaching into the path of the light beam is so easy to detect. It also ensures that in the cargo hold stored cargo does not hinder the path of the light beam 3, 3 '. The Path of the light beam 3, 3 'is, however, also with the deflection mirror 4 Predeterminable that this runs across the cargo hold 1.

At the end of the path of the light beam 3, 3 'distant from the light source 2 an electro-optical device 5 for detecting signals of the light beam 3, 3 ', in the present case a video camera. In front of the camera 5 is a semi-transparent mirror 8 is arranged, over which the light beam 3, 3 ' is partially deflected into the light beam 11 shown in dotted lines in FIG. 1 Light beam 11 is transmitted through an analyzer 9 to another electro-optical one Device 10, in the present case a radiation sensor. Another electro-optical device 6, in the present case a video camera, is such in the Cargo compartment 1 arranged that the path of the light beam 3, 3 'at least partly in their field of vision, which is indicated by the reference number 7 marked lines is limited. The detection system also points in accordance with the present invention, another electro-optical device 12, present a radiation sensor, which in its field of vision is 7 ' marked lines is limited and for capturing serves electromagnetic radiation in the IR and UV range. The boundary lines 7 'of the electro-optical device 12 describe the same as that Field of vision of the electro-optical device 6 delimiting lines 7 the edges a rotating body protruding into the cargo hold 1 if necessary.

Changes in the optical properties of the light beam 3, 3 'caused due to aerosol or smoke particles or streaks caused by heat caused by A possible fire in the cargo hold 1 will be caused by the electro-optical devices 5, 6, 10 and 12 as follows and from that not shown in FIG. 1, communicatively connected to the electro-optical devices 5, 6, 10 and 12 Computing device evaluated. The electro-optical devices 5, 6, 10 and 12 detected signals or images are on the part of the computing device in stored in a database. The currently recorded signals are thereby on the part of the computing device with the stored signals previously recorded compared. To increase the reliability of the detection are advantageously the deviations found in the comparison also on the part of stored in the computing device and based on the time profile of the Stored deviations Information about smoke and / or fire in the Cargo hold 1 generated.

Aerosol or smoke particles caused by a fire get into the way of the light beam 3, 3 'and cause diffuse scattering of light to the Aersol or smoke particles, absorption of light by the smoke or aerosol particles and a depolarization of the light beam 3, 3 'by multiple reflections of smoke or aerosol particles. Through scattering and multiple reflections of the The cross section of the light beam becomes the light beam on the aerosol or smoke particles 3, 3 'enlarged. This cross-sectional enlargement is based on the comparison the image signals currently detected by the electro-optical device 5 that of the electro-optical device 5 at a previous time detected signals and recorded by the computing device. exceeds the cross-sectional enlargement becomes a predetermined threshold on the part of the computing device generates an alarm signal which is then used for Display is brought, for example to initiate protective and / or auxiliary measures. A temporal change is advantageous with the threshold value the cross-sectional enlargement is taken into account, which advantageously in the frame a second threshold value is used for alarm signal generation and further increases the reliability of smoke and / or fire detection.

Next is based on the signals detected by the electro-optical device 5 on the part of the computing device as part of the comparison, a weakening of Luminance of the light beam 3, 3 'due to light absorption by aerosol or Smoke particles are detected and when a threshold value is undershot Alarm signal generated. The computing device also advantageously the weakening of the luminance by absorption with another time-dependent Threshold combined to increase the reliability of the detection.

The signals detected by the electro-optical device 10 from the light beam 3, 3 'decoupled light beam 11 provide information about one by multiple reflections depolarization of the polarized took place on aerosol or smoke particles Light beam 3, 3 'and 11. The analyzer 9 in front of the electro-optical device 10 is set such that without depolarization by aerosol or smoke particles behind the analyzer 9 no signal of the light beam 3, 3 'or 11 is detectable. The direction of polarization of the analyzer 9 is perpendicular to the direction of polarization of the light beam 3, 3 'supplied by the light source 2 or 11. Due to aerosol or smoke particles due to multiple reflections given depolarization effects of the light beam 3, 3 'have a polarization direction which can cross or pass through the analyzer. When capturing of a signal by means of the electro-optical device 10, this is therefore a Indication that the light beam 3, 3 'or 11 by aerosol or smoke particles in its direction of polarization was changed. Those of the electro-optical are advantageous Device 10 detected signals of the light beam 11 in terms of shape, Type, intensity and / or location recorded and when exceeded, reached or undershot a threshold value on the part of the computing device an alarm signal generated. Deviations detected by the computing device are advantageous saved and evaluated depending on the time in the manner of a forecast.

The electro-optical device 6 is detected along by aerosol or smoke particles the path of the light beam 3, 3 'scattered electromagnetic radiation. The Signals detected by the electro-optical device 6 are correspondingly the electro-optical device 5 with regard to the deviation in shape, type, Intensity and / or location evaluated and when a threshold value is reached the deviation on the part of the computing device generates an alarm signal. The of the electro-optical device 6 signals are detected by the Computing device stored and advantageously for a time-dependent Threshold used to generate an alarm signal.

The electro-optical device 12, in the present case a radiation sensor for detection Electromagnetic radiation in the IR and UV range in cargo hold 1 is used for direct detection of fire in the cargo hold 1. On the part of the computing device the signals detected by the electro-optical device 12 are also thereby evaluated by shape, type, intensity and / or location, advantageously in Dependence on time and size of the deviations using a time-dependent Threshold.

Fig. 2 shows an arrangement for expanding the beam 3 of the light source 2. Der collimated light beam 3 with a fixed polarization direction supplied by the light source 2 is made up of one of two collecting optical systems Expansion optics 13 expanded to the light beam 3 '. This enables more accurate Detection of changes in the collimated light beam 3 'as changes the optical properties caused by smoke and / or fire in the cargo hold are recorded over a larger cross-section and are easier to quantify. For suppression undesired secondary radiation is in front of the electro-optical device 5 a notch filter 14 with high selective transmission of the wavelength of Light beam 3 ', ie the wavelength of the light or radiation source 2, upstream.

Fig. 3 shows the basic structure of an arrangement for detecting streaks through heat development. The collimated light beam 3 'is through the Schlieren optics 15 depicted in an intermediate image plane in which the streak diaphragms 16 are located. From there, the lens 17 is re-imaged electro-optical device 5, in the present case a camera. Are on the way of the light beam 3 'between the light source 2 and Schlieren optics 15 through Heat streaks are present, so part of the Light beam deflected and hits the intermediate image plane instead of the latter surrounding streaking 16. The part of the Light beam can no longer be imaged by the camera optics 17. thereby occurs a darkening of the image recorded by the camera 5 and a Illustration of the streaks on. If the darkening falls below this Loss of light a certain brightness threshold value, on the part of the Computing device generates an alarm signal corresponding to the darkening or Darkening by scattering the light beam on aerosol or smoke particles.

Fig. 4 shows in a block diagram the basic flow of inventive method. In the marked with 18 Method step are by means of the electro-optical devices 5, 6, 10 and 12 images or signals captured and stored by the computing device, such as shown in Fig. 4 with the arrow marked 19. On the part of The captured images and signals according to brightness, Polarization, beam expansion, specific radiation and streaks evaluated, as shown in Fig. 4 with the process step labeled 20. The The result of the evaluation is used to determine deviations from the Normal state in a comparison 22 by one of the computing device performed comparison algorithm, as shown in FIG. 4 with 21 marked arrow shown. Unless there is a deviation from Normal condition, i.e. in the fire-free case, is present within the scope of the Algorithm running algorithm using the arrow marked 23 to method step 18 for recording images or signals by means of the electro-optical devices 5, 6, 10 and 12 have returned and the Steps 18 to 22 are repeated. In case of deviations from Normal condition, i.e. in the event of a fire, is determined from the Deviations an alarm signal is generated, which over the 24 marked arrow is fed to an alarm device, which a Corresponding alarm signal to initiate protective and / or auxiliary measures displays.

The exemplary embodiments shown in the figures serve only the Explanation of the invention and are not restrictive for this.

LIST OF REFERENCE NUMBERS

1

hold

2

light source

3, 3 '

beam of light

4

deflecting

5

electro-optical device

6

electro-optical device

7, 7 '

Visual range limit

8th

semi-transparent mirror

9

analyzer

10

electro-optical device

11

Light beam (side arm)

12

electro-optical device

13

expansion optics

14

filter

15

Schlieren optics

16

Schlieren apertures (bright field method)

17

Lens (electro-optical device 5)

18

Process step ("taking an image / signal")

19

Storage (image / signal)

20

evaluation

21

Feeding (signal comparison)

22

Comparison "deviation from normal state"

23

Repetition of the procedure (no deviation from normal condition)

24

alarm

25

alarm display

Claims (20)

Method for detecting fires in rooms, in particular freight rooms, sales rooms or the like, wherein electromagnetic radiation (3) is guided over a predetermined distance through a room to be monitored and at least one electro-optical device (5, 6, 10, 12) for detecting optical ones Signals is supplied
characterized in that on the part of a computing device communicatively connected to the electro-optical device (5, 6, 10, 12) on the basis of at least one comparison of signals of the electromagnetic radiation (3) detected by the electro-optical device (5, 6, 10, 12) with stored Signals of the electromagnetic radiation deviations from the shape and / or type and / or intensity and / or position of the electromagnetic radiation (3) are determined and an alarm signal is generated when they reach, fall below or exceed at least one predeterminable threshold value. A method according to claim 1, characterized in that the alarm signal is displayed. Method according to claim 1 or claim 2, characterized in that the electromagnetic radiation is a light beam (3, 3 ', 11). Method according to one of claims 1 to 3, characterized in that the electromagnetic radiation is a beam of parallel electromagnetic radiation. Method according to one of claims 1 to 4, characterized in that the electromagnetic radiation is generated by a laser. Method according to one of claims 1 to 5, characterized in that the electromagnetic radiation is expanded. Method according to one of claims 1 to 6, characterized in that the electromagnetic radiation has a defined polarization direction. Method according to one of claims 1 to 7, characterized in that diffuse scattering of electromagnetic radiation on smoke particles is evaluated. Method according to one of claims 1 to 8, characterized in that the absorption of electromagnetic radiation by smoke particles is evaluated. Method according to one of claims 1 to 9, characterized in that the depolarization of electromagnetic radiation by smoke is upgraded. Method according to one of claims 1 to 10, characterized in that thermal streaks are detected and evaluated. A method according to claim 11, characterized in that electromagnetic radiation from a source of fire is detected and evaluated. System for detection of fires in rooms, in particular Cargo spaces, sales rooms, storage rooms or the like, for Implementation of the method according to one of claims 1 to 12, comprising a light source (2) for generating a light beam (3), at least one electro-optical device (5, 6, 10, 12) for detecting optical signals and one with the electro-optical device (5, 6, 10, 12) communicatively connected computing device for signal evaluation. System according to claim 13, characterized by at least one deflecting mirror (4) for guiding the light beam (3) generated by the light source (2) over a predetermined distance to the electro-optical device (5, 6, 10, 12). System according to one of claims 13 or 14, characterized in that the electro-optical device (5, 6) is a video camera. System according to one of claims 13 to 15, characterized in that the electro-optical device (10, 12) is a radiation sensor. System according to one of claims 13 to 16, characterized by an expansion optics (13) arranged in the region of the output of the light source (2) for generating a parallel light beam (3 '). System according to one of the preceding claims, characterized by a Schlieren optics (15) and Schlieren apertures (16) arranged in front of the electro-optical device (5, 6, 10, 12). System according to one of the preceding claims, characterized by a blocking filter (14) arranged in front of the electro-optical device (5, 6, 10, 12). System according to one of the preceding claims, characterized in that the path is arranged in the area of the ceiling of the cargo hold (1).

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