RU2756593C1 - Scanning flame detector with a function of determining the angular coordinate of the fire source - Google Patents

Abstract

FIELD: firefighting.

SUBSTANCE: scanning flame detector with a function of determining the angular coordinate of the fire source relates to firefighting flame detectors and is intended for detecting fire sources by ultraviolet and/or infrared radiation of the flame and determining the angular coordinates thereof. The detector has a body, on the face part whereof a window is made in the form of an optically transparent side surface of a cylinder with an arc length limited by the maximum viewing angle of the detector in the horizontal plane. An emission receiver is installed near the central axis of the body, a rotary scanning apparatus constituting a rotating cylindrical slit obturator is installed outside of the window, a slit gap is made in the lateral and the lower parts of the obturator, ensuring illumination of the sensitive element. A sectoral cut is made in the obturator opposite the slit gap, following the form of the window. The aperture angle of the sectoral cut is equal to the maximum viewing angle of the sensitive element.

EFFECT: creation of a scanning flame detector with a function of determining the angular coordinate of the fire source.

9 cl, 5 dwg

Description

The detector belongs to fire alarm systems, in particular to fire flame detectors, and is designed to detect fires by ultraviolet (UV) and / or infrared (IR) radiation of the flame and determine their angular coordinates over the area of the protected room in order to increase efficiency and ensure targeting automatic fire extinguishing systems.

The existing traditional automatic detection systems based on point heat, smoke or gas fire detectors do not allow to determine the location of the fire in the premises with a given accuracy and inertia:

- for the implementation of coordinate detection of a fire inside a room, such systems should be built according to the address principle, where the resolution depends on the number of detectors (to ensure high accuracy, a large number of detectors are needed, which complicates and increases the cost of the system);

- topological complexity of scaling of coordinate fire detection systems based on point detectors.

Flame detectors are one of the types of detectors with high efficiency (speed) of detecting a fire at the initial phase of a flame combustion in comparison with other means of detection.

Modern traditional flame detectors have a fairly high sensitivity and, accordingly, a long range and a significant protected area (patents RU 2300807, RU 114547, RU 114386, RU 2296370). However, such detectors do not have the ability to identify the location and determine the number of flames.

To determine the angular coordinates of the position of the sources of ignition, flame detectors with a matrix structure of the sensitive element are used. Known flame detector FlameVision "TYCO" (patents US 6528788, US 6476859, US 6818893) with a sensitive element consisting of an array of single-element narrow-beam IR sensors (pixels), forming a rectangular detection zone in the form of an array of 16 × 16 cells with a radiation pattern of 90 ° in the horizontal plane and 80 ° - in the vertical plane.

However, the accuracy of coordinate detection in such devices depends on the resolution of the sensing element (the number of pixels per unit area).

Another way to determine the coordinates of a fire source in a room is to use the scanning method, which consists in analyzing the space of a controlled room by viewing and evaluating the radiation intensity of a fire source when the instantaneous field of view (directional pattern) moves across the detector's field of view.

Robotic fire extinguishing installations widely used to protect public and industrial facilities (RUE "Guard" patent RU 63692; "EFER" patents RU 2677622, RU 2424837; RU 191628) based on programmed fire nozzles (sprinklers) use the principle of targeted detection of a fire source on based on optical IR flame detectors with a narrow viewing angle (from 3 to 12 degrees).

In such installations, the scanning of the protected area (determination of the angular direction of the location of the hearth relative to the fire robot) is carried out by automatically moving the fire nozzle on which the flame sensor is installed (with the optical axis coinciding with the direction of supply of the extinguishing agent) along a given trajectory.

This approach requires the use of additional fire alarm devices that control the entire protected area and issue an "Alarm" signal in the event of a fire, since the IR sensor has a narrow viewing angle and is used only for automatic guidance of the fire barrel to the fire source at the specified coordinates.

In addition, the use of an IR receiver is susceptible to external sources of optical interference (for example, solar radiation, heated bodies), and to reduce the number of false alarms, additional detection channels (IR, UV or Video) and more complex signal processing algorithms are required, which significantly complicates and increases the cost of construction.

The aim of the invention is to create a device for the coordinate fire detection system for detecting one or more fire foci, determining the angular coordinates of the foci, providing noise immunity to optical interference, developing a functional system and method for implementing the device.

The technical result of solving this goal is the detection of the source (s) of the fire, quick and noise-free determination of the sector (s) of the protected premises, in which the source (s) of the fire are recorded.

The goal is achieved by creating a scanning flame detector with the function of determining the angular coordinate of the fire source, characterized by the execution of a cylindrical body with an upper rectangular base, through which the body is connected to a tilt-swivel bracket, a cutout is made in the front of the body, a transparent window is installed in the cutout in the form of a lateral surface cylinder with a radius equal to the radius of the cylindrical body and the arc length limited by the maximum viewing angle of the detector, a radiation photodetector is installed inside the body near its central part, behind the transparent window there is a rotary scanning device, which is a rotating cylindrical slotted obturator with the possibility of illumination of the sensitive element of the photodetector by a sector with an opening angle in the horizontal plane much smaller than the maximum viewing angle of the detector's sensitive element, in the obturator on the opposite side from the slot gap, a wide sector cutout is made, made in the shape of a window, the opening angle of the sector cutout is chosen equal to the maximum viewing angle of the sensing element and corresponds to the most complete illumination of the photodetector, a printed circuit board of a microprocessor unit with electronic elements is installed inside the housing in a cross section and with an electric one installed coaxially with the central axis of the housing shutter drive. The transparent window can be made of quartz glass or leucosapphire with the possibility of passing ultraviolet and infrared radiation.

The housing can have an additional window for an indicator LED located on the front.

The housing can have a sounder.

The photodetector can be made in the form of one or more optical sensors that register the electromagnetic radiation of the flame in the ultraviolet and / or infrared spectral ranges, characteristic radiation bands of various combustible substances and materials.

The region of maximum spectral sensitivity of the photodetector elements is made: for infrared sub-ranges: 1.4 ... 1.5 µm, 4.3 ... 4.5 µm; for the ultraviolet subrange: 0.18 ... 0.26 microns.

The functional system of the scanning flame detector with the function of determining the angular coordinate of the flame seat is characterized by the inclusion of a sensitive element and a high-level voltage generator connected to it, which is connected to a microprocessor unit, which is connected and controls the operation of the obturator electric drive, the operation of the light indication and sound warning unit, switching a block for activating external devices, a digital interface for inclusion in intelligent systems, in addition to the microprocessor block, a block for controlling the position of the shutter is connected, the sensing element is connected to the microprocessor block by means of an amplifier-shaper.

A method of implementing a scanning flame detector with the function of determining the angular coordinate of a fire center contains the stages in which:

- select the point of placement of the detector, taking into account the viewing angle and direction of the optical axis of the detector;

- divide the entire monitored detection area into N independent sectors, taking into account the required coordination accuracy (zone selectivity of detection), while fulfilling the requirement of compliance with the maximum viewing angle ϕ, divided into N equal independent sectors with a smaller viewing angle β, according to the formula ϕ = β⋅N ;

- control the protected space continuously in the "Standby mode" in the absence of a fire source with a maximum viewing angle ϕ of the photodetector in the horizontal and vertical planes;

- generate a "Fire" signal to the external circuit when a flame occurs in the detection zone of the detector and transfer the detector to the "Scanning" mode to search for the angular direction of the fire source;

- rotate the slotted shutter, evaluate the radiation intensity for each of the N detection sectors, determine the sector with the maximum value of the intensity of the incoming radiation;

- fixing in the memory of the microprocessor control unit of the detector information about the presence of each fire and the angular direction of the detected sector in which the fire is located;

- provide software masking (blocking) of one or several detection sectors to exclude false alarms from the constant or probable presence of natural sources of open radiation that are not fire;

- use in the photodetector of radiation several optical sensors that register the electromagnetic radiation of the flame in the ultraviolet and / or infrared spectral subranges;

- perform a self-test of the operational state, in which all internal electronic and optical circuits of the detector are checked in conditions of short-term complete overlap of the entire field of view;

- additionally provide high accuracy in determining the location of the fire source and high noise immunity due to the implementation of the multispectral principle of detection.

The invention is explained in more detail by means of the drawings shown in FIGS. 1 to FIG. 5.

.FIG. 1. General view of the detector in the "Scanning" mode from the front in perspective

...

.FIG. 2. General view of the detector in the "Standby mode" from the front in the foreshortening

...

.FIG. 3. General view of the detector in the "Scanning" mode from below in perspective

...

FIG. 4. Functional diagram of the detector.

FIG. 5. Plan for the placement of the detector in the protected room, indicating the boundaries of the survey by sectors and the location of the fire center.

The scanning-type flame detector contains a rectangular base 2 mounted on a tilt-swivel bracket 1 with the possibility of orientation in any required direction and a cylindrical body 3 fixed on it. An optically transparent window 4 is installed on the front of the body in the form of a lateral surface of a cylinder with a radius equal to the radius of the cylindrical body , and the length of the arc, limited by the maximum viewing angle of the detector in the horizontal plane. Window 4 is made of quartz glass or leucosapphire and allows UV and IR radiation to pass to the sensitive element of the detector. The housing is additionally equipped with a window for the indicator LED 5, located on the front of the detector. Radiation receiver 6 is installed inside the housing near its central axis.

A rotary scanning device is installed in the body behind the transparent window, which is a rotating cylindrical slotted obturator 7 for blocking the radiation flux incident on the photodetector. In the lateral surface and the lower base of the obturator, a slotted gap 8 is made, which ensures the formation of illumination of the sensitive element by a sector with an opening angle in the horizontal plane much smaller than the maximum viewing angle of the detector's sensitive element. In this case, in the obturator on the opposite side of the slotted gap 8 there is a sector cutout 9 made in the shape of a window. The opening angle of the sector cut-out is chosen equal to the maximum viewing angle of the detector's sensitive element and corresponds to the open state of the detector, in which the flame radiation unhindered reaches the receiver. A printed circuit board 10 with electronic elements of the microprocessor unit is installed inside the body in cross section. The obturator is attached to the axle and is driven by an electric drive 11 mounted on the printed circuit board coaxially with the central axis of the housing.

The photodetector is made in the form of one or more optical sensors that register the electromagnetic radiation of the flame in the UV and / or IR spectral subranges, characteristic of the radiation bands of various combustible substances and materials.

The simultaneous use of several sensors with different spectral sensitivity ranges (multispectral principle of detection in the UV and IR spectrum) will significantly increase the reliability and reliability of flame detection, as well as increase the level of noise immunity from external background noise (solar radiation, artificial light sources, heated objects, discharges lightning, etc.).

Functionally, the detector consists of: a sensitive element 12 (UV, IR sensor), a high-level voltage generator 13, a control unit for the position of the shutter 14, an amplifier-pulse shaper 15, a microprocessor unit 16, an electric drive of the shutter 17, a visual and sound indication unit 18, a switching unit to activate connected external devices 19, a digital interface for inclusion in intelligent systems 20.

The principle of operation of a scanning detector with the function of determining the angular coordinate of the fire source is explained by the plan, which shows: the location of the detector 21, the boundaries of the protected room 22, the location of the fire source 23, the boundaries of the sectors 24, the sector 25, in which the fire is located.

When turned on, the microprocessor unit 16 initiates the transition of the detector to the “Standby” mode by acting on the electric drive of the obturator 17 and monitoring the achievement of the initial position corresponding to the “Standby” mode using the control unit for the position of the obturator 14. The microprocessor unit 16 by means of controlling the high-level voltage generator 13 carries out the supply of electrical power to the optical sensor 12 with the required voltage.

If there is an open flame source in the sensor's field of view, pulses with a frequency correlating with the intensity of the radiation incident on the sensor are fed to the pulse shaping amplifier 15, where they are converted and fed to the input of the microprocessor unit.

The microprocessor unit processes the incoming signal according to a given algorithm. If the conditions laid down in the algorithm for reliable detection of a fire source are met, the microprocessor unit activates the "Scanning" mode, sending a signal to the shutter motor and switching unit 19, signaling the presence of a fire source, and analyzing the useful signal from the optical sensor.

In the detector's operation algorithm, the entire field of view of the optical sensor is divided into a certain fixed number of radial sectors, while the pulses generated by the sensor and corresponding to the presence of a flame in the detection zone are recorded for each sector separately.

The processing of the received information about the intensity of the flame radiation for each detection sector in the microprocessor unit makes it possible to select one or several areas in the angular representation relative to the optical axis of the detector, in which the probable fire source is located.

These data, as well as information about the current mode, are stored in the internal memory of the detector (microprocessor unit) and can be read by intelligent external systems using the digital interface 20. Information about the modes of operation of the detector is given unambiguously using the light and sound indication unit 18.

The detector operation algorithm consists in determining the angular direction of the position of the flame in the horizontal plane of the room by dividing the entire monitored detection zone with a maximum viewing angle ϕ into N equal independent sectors with a smaller viewing angle β (Fig. 5) so that ϕ = β⋅N.

The number of sectors N is selected taking into account the required coordination accuracy (zone selectivity of detection).

In "Standby mode", in the absence of a flame source, the detector is in the open state and continuously monitors the detection zone with the maximum viewing angle (p in the horizontal and vertical planes.

When a fire source occurs in the detector's detection zone, a "Fire" signal is generated, after which the detector switches to the "Scanning" mode of the protected zone to search for the angular direction of the fire source position.

In the "Scanning" mode, the detector sequentially evaluates the intensity of radiation from the flame for each of the N sectors of detection and determines the sector with the intensity of the incoming radiation exceeding a fixed threshold value.

Information about the presence of a fire and the radial direction of the detected sector, in which the flame is located, is stored in the detector's memory and can be read via a wired or wireless interface by an external device (for example, a coordinate fire extinguishing device).

This approach to building a detector based on sectoral selectivity makes it possible to detect and determine the angular coordinates of several fires in different sectors at once. In addition, it is possible to programmatically mask (block) one or more sectors of detection to exclude false alarms from the constant or probable presence of natural sources of open flames that are not fire.

Also, the detector has an additional function of self-monitoring of the operational state, in which all internal electronic and optical circuits of the detector are checked. The principle of self-testing is that at the moment the detector is triggered and the "Fire" signal is issued (before the start of the scanning process), the entire field of view of the detector is briefly covered and the absence of a signal from the sensitive element is checked in order to exclude false positive alarms of the detector due to failure sensing element.

The use of the scanning method in a flame detector to determine the angular coordinate of a fire in a room allows for a detection time of less than 5 s and a search time for the angular direction of the location of test foci TP-5, TP-6 in accordance with GOST R 53325-2012 no more than 30 s at a distance of at least 25 m.

The proposed scanning flame detector has new qualitative properties that distinguish it from existing analogues:

- a new principle of construction of scanning flame detectors;

- a new algorithm for detecting and determining the coordinates of the source of fire in the room;

- the ability to coordinate detection of several fires at once;

- the possibility of masking (blocking) individual sectors of the detection zone to exclude false alarms from known sources of interference that are not fire;

- the presence of a self-monitoring function, in which all internal electronic and optical circuits of the detectors are checked for operability and false alarms are excluded;

- high accuracy in determining the location of the fire source;

- high noise immunity in relation to optical interference due to the possibility of implementing the multispectral principle of detection in the UV or IR ranges.

The effectiveness of the introduction of a coordinate detection system (scanning detectors) into automatic fire extinguishing installations with a directed supply of extinguishing agent will increase the extinguishing efficiency and reduce damage:

- from a fire due to early detection and determination of the coordinates of the flame source and targeted supply of a fire extinguishing agent (OTV) to a given point (local zone);

- from the excessive use of OTS due to fast and guaranteed extinguishing and stopping the supply of OTS in the absence of signs of combustion.

Claims (19)

1. Scanning flame detector with the function of determining the angular coordinate of the fire center, characterized by the execution of a cylindrical body with an upper rectangular base, by means of which the body is connected to a tilting bracket, a cutout is made in the front part of the body, a transparent window is installed in the cutout in the form of a lateral surface of a cylinder with a radius , equal to the radius of the cylindrical body, and the arc length limited by the maximum viewing angle of the detector, a radiation photodetector is installed inside the body near its central part, behind the transparent window there is a rotary scanning device, which is a rotating cylindrical slotted obturator with the possibility of forming illumination of the sensitive element of the photodetector with a sector with opening angle in the horizontal plane, less than the maximum viewing angle of the detector's sensitive element, a wide sector cutout is made in the obturator on the opposite side of the slot gap, Based on the shape of the window, the opening angle of the sector cutout is chosen equal to the maximum viewing angle of the sensitive element and corresponds to the full illumination of the photodetector; inside the case, in the cross section behind the photodetector, there is a printed circuit board of a microprocessor unit with electronic elements and with an electric shutter drive installed coaxially with the central axis of the case. 2. The detector according to claim 1, characterized in that the transparent window is made of quartz glass with the possibility of passing ultraviolet and infrared radiation. 3. The detector according to claim 1, characterized in that the transparent window is made of leucosapphire with the possibility of passing ultraviolet and infrared radiation. 4. The detector according to claim 1, characterized in that the housing has an additional window for the indicator LED located on the front part. 5. The detector according to claim 1, characterized in that the housing has a sounder. 6. The detector according to claim. 1, characterized in that the photodetector can be made in the form of at least one optical sensor that registers the electromagnetic radiation of the flame in the ultraviolet and / or infrared spectral subranges, characteristic radiation bands of various combustible substances and materials. 7. The detector according to claim 1, characterized in that the area of maximum spectral sensitivity of the photodetector elements is made for infrared subranges: 1.4 ... 1.5 μm, 4.3 ... 4.5 μm; for the ultraviolet subrange: 0.18 ... 0.26 microns. 8. Functional system of the scanning flame detector with the function of determining the angular coordinate of the flame seat, characterized by the inclusion of a sensitive element and a high-level voltage generator connected to it, which is connected to a microprocessor unit, which is connected and controls the operation of the shutter motor, the operation of the light indication unit and sound notification, a switching unit for activating external devices, a digital interface for inclusion in intelligent systems, in addition to the microprocessor unit, a block for controlling the position of the shutter is connected, the sensitive element is connected to the microprocessor unit by means of an amplifier-shaper. 9. A method of implementing a scanning flame detector with the function of determining the angular coordinate of a fire center, comprising stages in which: - select the point of placement of the detector, taking into account the viewing angle and direction of the optical axis of the detector; - divide the entire monitored detection area into N independent sectors, taking into account the zone selectivity of detection, while fulfilling the requirement of compliance with the maximum viewing angle ϕ, divided into N equal independent sectors with a smaller viewing angle β, according to the formula ϕ = β⋅N; - control the protected space continuously in the "Standby mode" in the absence of a fire source with a maximum viewing angle ϕ of the photodetector in the horizontal and vertical planes; - generate a "Fire" signal to the external circuit when a flame occurs in the detection zone of the detector and transfer the detector to the "Scanning" mode to search for the angular direction of the fire source; - rotate the slotted shutter, evaluate the radiation intensity for each of the N detection sectors, determine the sector with the maximum value of the intensity of the incoming radiation; - fixing in the memory of the microprocessor control unit of the detector information about the presence of each fire and the angular direction of the detected sector in which the hearth is located; - provide software masking of one or more detection sectors to exclude false alarms from the constant or probable presence of natural sources of open radiation that are not fire; - use in the photodetector of radiation several optical sensors that register the electromagnetic radiation of the flame in the ultraviolet and / or infrared spectral subranges; - perform a self-test of the operational state, in which all internal electronic and optical circuits of the detector are checked in conditions of short-term complete overlap of the entire field of view; - additionally provide high accuracy in determining the location of the fire source and high noise immunity due to the implementation of the multispectral principle of detection.

Images