RU2665868C1 - Method of smoke detection and device for implementation thereof - Google Patents

Abstract

FIELD: fire safety; alarm system.SUBSTANCE: invention relates to the field of fire alarm. Method and a device implementing it are described, comprising a clock generator, a control and storage circuit, emitter of light pulses, main and additional receivers of reflected light pulse signals, synchronous detection and reset circuits, the determinant of the ratios of the change in the intensity of the scattering of light radiation, which contains two logarithm, connected through a divisor with an antilogarithmator, the identifier of the scattering of light radiation, the synchronization circuit of the information signal and the driver of the smoke detection signal or the process control signal.EFFECT: technical result consists in increasing the reliability of detection of the optical density of smoke with reducing the measurement error and eliminating dustiness factors, false triggering with the formation of technological control signals.3 cl, 10 dwg

Description

The invention relates to the field of fire safety, and in particular to methods for detecting smoke, and can be used to detect fire, accompanied by the appearance of smoke in the early stages of a fire in enclosed spaces of various buildings and structures.

A known method of detecting smoke, described in the patent of the Russian Federation No. 2134907, IPC G08B 17/10 (1995.01), published on 08/20/99, which consists in the formation of periodic bursts of light pulses emitted into an optical camera with light-absorbing walls, the subsequent reception of reflected signals at an angle different from the optical axis of the radiation, comparing them with a threshold value and memorizing with the subsequent formation of a smoke detection signal, provided that the entire packet of light pulses is received, and in the intervals between radiation with etovyh burst when reliable information about the absence of a useful signal with the subsequent formation of the signal or noise and smoke registration correction signal. If the generated signal is detected by the comparison circuit at the time of interrogation of the optical system, then a counting pulse is generated by the control and storing circuit, which is stored as the "first" burst pulse, and the smoke detection signal is generated after receiving the entire burst of pulses. The signal generated in the interval between the registration of the individual emitted light pulses of the burst and the threshold is exceeded, form a low-level logic signal, which is sent to the interference detection circuit, and then to the control and memory circuit, resetting the counter and inhibiting the pulse count, thereby preventing the formation of a smoke detection signal.

The disadvantage of this method is the low reliability due to the introduction of the operation of generating an interference signal with subsequent exposure to the formation of a smoke detection signal. At the same time, in the absence of smoke, the appearance of any interference caused by transients causing a decrease in the threshold value and comparable in duration with the duration of the pulse train can generate a false smoke detection signal.

As a prototype, the well-known method for detecting smoke is selected, described in the patent of the Russian Federation No. 2256229, IPC G08B 17/10 (2000.01) and published on July 10, 2005, which consists in the formation of synchronous periodic sequences of counting pulses and light pulses emitted into the optical camera with light-absorbing walls, the subsequent reception of the reflected signals arriving at an angle different from the optical axis of the radiation, converting the received reflected signals into electrical signals, comparing them with a threshold value and, if there is a reception of reflected signals, the corresponding electrical signals are synchronously detected before comparison with the threshold value, and signals exceeding the threshold value are set to the beginning of the period for the accumulation and counting of counting pulses synchronous to the corresponding periodic light pulses, followed by the formation of a smoke detection signal at the accumulation of a given number of counting pulses or a reset signal when there is a shortage. The main disadvantage of this method is the inability to determine the reliability of the measurement in the presence of foreign particles in the smoke detection zone, for example, industrial dust or all kinds of aerosols. The lack of control of the dustiness of the optical channel reduces the reliability of detection and registration of smoke at an early stage of ignition.

The objective of the invention is to increase the reliability of recording the optical density of smoke, regardless of the nature of smoldering or burning material, as well as to reduce the error in measuring the optical density of smoke by eliminating the dust factor of the received reflected signals during smoke registration and the subsequent formation of a fire alarm with high reliability, as in to white ", and to" black "smokes regardless of the nature of smoldering or burning material.

The problem is solved by the method of smoke detection, which consists in the formation of synchronous periodic sequences of counting pulses and emitted into the optical camera with light-absorbing walls of light pulses, the main receiver receiving the reflected light pulses arriving at an angle different from the optical axis of radiation, converting them into electrical signals, followed by synchronous detection and comparison with the first threshold value, determination by signals of reflected light pulses, etc. raising the threshold value, the beginning of the period for the accumulation and counting of the number of counting pulses synchronous to the corresponding light pulses, the formation of a smoke registration signal during the accumulation of a given number of counting pulses.

New in the claimed method is that simultaneously with the main receiver of the reflected signals form the reception and conversion into electrical signals of the reflected signals synchronous to the light pulses, an additional receiver located at an angle different from the optical axis of the radiation in the side scattering zone relative to the optical axis of the radiation of light pulses . The obtained values of the reflected signals are subsequently converted to the ratio of current changes in the corresponding values of the received and converted reflected signals between the main and additional receivers of the reflected signals in a given period of time synchronous to the emitted light pulses. Each generated ratio of the current changes in the corresponding values is simultaneously compared with the given second upper and third lower threshold signal values. If the comparison results coincide with the threshold signal values of the ratios of the received reflected signals with the signal values inside the interval of the specified second upper and third lower threshold values, then a smoke registration signal is generated during the accumulation of the specified number of counting pulses, and if there are corresponding signal values outside the interval of the specified second upper and a third lower threshold value form a process control signal. Moreover, the upper and lower threshold values of the signals are determined in proportion to the intensity of scattering of light radiation on the particles of the corresponding combustion products for comparison with the current changes in the ratios of the corresponding values of the reflected signals of the main receiver and the additional receiver.

The technical result consists in increasing the reliability of detecting optical density of smoke and ensuring smoke detection at an early stage of a fire by determining the current changes in the results of the ratios corresponding to the values of the synchronously received reflected signals of the main receiver and the additional receiver, and then comparing the obtained results of the ratios with the specified upper and lower threshold signal values. The generated smoke detection signal does not depend on the dustiness of the optical camera, since the compensation of errors from dustiness is excluded by determining the ratios of the measured values of the corresponding synchronously received reflected signals of the primary and secondary receivers, for example, with equal current-voltage characteristics or with given characteristics, taking into account which threshold values are formed. In addition, due to this, it is possible to significantly lower the threshold of sensitivity of the detector, which will increase the speed of its operation. When comparing and matching the signals of the results of the ratios with the values within the interval of the set threshold values, they provide the reliability of the formation of a fire signal, regardless of the nature of the smoldering or burning material, since the particles of the combustion products have stable sizes with a small spread. And the technological control signals are formed by comparing the current changes in the results of the ratios outside the interval of threshold values of the corresponding synchronously received reflected signals of the main and additional receivers. An informational message from the technological control signal about the presence of factors causing a false alarm is generated if, after comparing the signals of the current changes in the results of the ratios, it is greater than the threshold value. Process control signal for the presence of, for example, aerosols, steam, etc. form if, after comparing the signals of the current changes in the results of the ratios is less than the pore value. The specified upper and lower threshold signal values are determined in proportion to the intensity of scattering of light radiation on the linear particle sizes of the corresponding combustion products.

The claimed method for detecting smoke is based on measuring the intensity of scattering of light by suspended smoke particles in air aerosols, which can have sizes from 0.1 to 0.5 microns. When smoke spreads in convection air flows, smaller particles can form larger particles, causing a decrease in their concentration. In addition, the presence of accompanying particles from 0.5 to 10 microns of dust and all kinds of aerosols is possible. The scattering intensity of light radiation in the propagated medium depends on the size of the detected particles and the sensitivity of the light radiation receivers, which varies non-uniformly with its location in the smoke measurement registration area. So in the case of elastic scattering of light radiation of particles with linear dimensions “a” - a radius that is much less than the wavelength “λ” (the so-called Rayleigh scattering a≤.λ / 15), there is a partial polarization, depending on the angle of scattering of radiation. If the linear dimensions of particles with a radius “α” are larger or comparable with the wavelength “λ”, namely а> λ / 15, then according to the Mie theory developed by G. Mie in 1908, there is scattering asymmetry forward and backward - with prevailing forward scattering, due to the influence of re-emission by particles of the medium, and the scattering intensity in the direction of the beam exceeds the intensity by 2–3 times (Mie effect). In this case, the scattering indicatrix is symmetric about the optical axis of the primary radiation of the emitted light pulses into the optical camera and is relatively perpendicular to its plane. The scattering coefficient is determined by the formula ε _λ = α λ ^-α , where λ is the wavelength, α is the scattering coefficient varies from 0 to 4, α is proportional to the number of suspended particles. For large particles (kα >> 1), the attenuation coefficient of light radiation is ε = 2πα ² , i.e. it does not depend on λ, the wavelength of electromagnetic radiation, and is equal to twice the diameter of the spherical particle 2πα ² . This is explained by the fact that half the attenuation occurs due to scattering and absorption inside the particle, and the other, also πα ^{2, is} caused by diffraction (scattering) of light on the particle’s contour. The total scattering coefficient of a particle is represented by the sum of the coefficients for individual partial waves and is valid not only for spherical particles, but also for irregularly shaped particles, including particles with a refractive index that differs greatly from the refractive index of the medium. (Matveev A.N., Optics, ed. "Higher School", M., 1985. S. 290, 296; Van de Hulst, Scattering of Light by Small Particles, ed. Foreign Literature, M, 1961. P. 153-155 ; http://www.ereadr.org/book/nauka_i_ucheba/3760-rasseyanie-sveta-malymi-chasticami/153).

The applicant conducted laboratory tests for the smoke chambers of fire detectors, the compliance of the dependence of the intensity of radiation scattering by suspended smoke particles in air aerosols on their size, confirming the analytical solution - Mi in the form of series, in which kd = 2πd / λ, where

k is the wave number 2 π / λ;

d is the linear particle size;

π is a mathematical constant equal to approximately 3.14;

λ is the wavelength of electromagnetic radiation.

Based on the test results, the ratios of current changes in the corresponding values of the received and converted reflected signals between the primary and secondary receivers of the reflected signals are determined, which for smoke are 1.5-2.0, dust - 0.2-0.9, and for steam - 5-12. The choice of the values of the second upper and third lower threshold signal values for smoke detection includes the range covered by the values excluding steam and dust. The ratios of the current changes in the corresponding values of the received and converted reflected signals between the primary and secondary receivers do not affect the detector speed, which depends on the sensitivity threshold of the detector itself. However, in order to protect against false interference, most existing detectors are forced to raise the sensitivity threshold. In this method of smoke detection and device for its implementation, protection from false interference is provided by the ratio of the received reflected signals of the main receiver to the additional one, due to this it is possible to significantly lower the sensitivity threshold of the detector, which leads to an increase in the response speed.

In FIG. 1 is a flowchart of the inventive method for detecting smoke; FIG. 2, 3-9 show an example implementation of a method for detecting smoke; in FIG. 10 presents the test results - graphs of the correspondence of the intensity of radiation scattering by suspended smoke particles in air aerosols.

The flowchart of the inventive smoke detection method in FIG. 1 contains a clock generator 1, a control and memory circuit 2, an emitter of 3 light pulses, a main 4 and an additional 5 receivers of reflected signals of light pulses of an emitter 3, a synchronous detection circuit 6, a reset circuit 7, a determinant of 8 ratios of changes in the intensity of light radiation scattering, identifier 9 scattering of light radiation, an information signal synchronization circuit 10, a driver 11 of a smoke registration signal or a process control signal. Moreover, the clock generator 1, associated with the corresponding outputs with the first and second inputs of the control and memory circuit 2, is made on three binary counters - the first, second and third, and the V-input and R-input of each of them are sequentially the first and second, third and its fourth, fifth and sixth inputs, and the given output of each binary counter are its corresponding outputs, while its second output is connected to the C-inputs of its first and second binary counters, and the third output is connected to the C-input of its third binary counter and, while the first output of the first binary counter is connected to its third input of the second binary counter, the first input of the synchronous detection circuit 6 and the emitter 3 connected through an optical camera with light-absorbing walls to the main 4 receiver of the reflected signals, the output of which is connected to the second input of the circuit 6 synchronous detection associated with the third input with the reset circuit 7, and optically coupled with the emitter 3 additional 4 receiver of the reflected signals, the output of which is connected to the input of the determinant 8, the ratio the change in the scattering intensity associated with another input with the output of the main 3 receiver, and the output through the light scattering identifier 9 with the input of the synchronization circuit 10, the first input of which is connected to the output of the synchronous detection circuit 6, and the first output of the synchronization circuit 10 is connected to the fourth and the fifth inputs of the control and storing circuit 2, and the second output is connected to the sixth input of the control and storing circuit 2, the second and third outputs of which are connected to the corresponding inputs of the shaper 11.

The method of detecting smoke, which consists in the fact that the sequence of rectangular pulses generated at a given frequency by the clock generator 1 (Fig. 1, an implementation example in Fig. 2), and converted by the first binary counter of the control and storage circuit 2 (Fig. 1) into a sequence of determining the time for converting electrical signals into light pulses by the emitter 3 (Fig. 1, the implementation example in Fig. 3) is emitted into an optical camera with light-absorbing walls (not shown).

Arriving at an angle different from the optical axis of radiation, the reflected light pulses are simultaneously received by the main 4 receiver (Fig. 1, an example implementation in Fig. 4) and located in the side scattering zone relative to the optical axis of the radiation of light pulses by an additional 5 receiver (Fig. 1, the implementation example in Fig. 4), and then the received reflected signals are converted into electrical signals.

Simultaneously with the sequence for converting electrical signals to light emitter 3 (Fig. 1) form a synchronous periodic sequence of counting pulses to the third input of the control and memory circuit 2 - V-input of the second binary counter of the circuit (Fig. 1), for the formation of the RC circuit circuit 6 synchronous detection (Fig. 1, an example implementation in Fig. 5) of the enable signal through the synchronization circuit 10 to the fourth input of the control and memory circuit 2 - the R-input of the second binary counter (Fig. 1), which reset it second binary counter in the absence of reception of the reflected signal 4 main receiver.

The received and converted reflected light pulses of the main 4 receiver are subjected to synchronous detection and subsequent comparison with the first threshold value by the synchronous detection circuit 6, determining the beginning of the period for the accumulation and counting of the number of counting pulses of a given periodic sequence synchronous to the corresponding light pulses to form a fire signal. When receiving signals from the main 4 receiver below the first threshold signal, at the output of the synchronous detection circuit 6, signals are generated that are transmitted to the reset circuit 7 (Fig. 1, an implementation example of Fig. 6) and through the synchronization circuit 10 to the fourth input of the control circuit 2 and storing - the R-input of the second binary counter (Fig. 1), reset the second binary counter of the control and storing circuit 2 (Fig. 1).

If there is a reception and conversion of the reflected signals by the main 4 receiver, exceeding the first threshold signal value specified by the resistor and the second logic circuit AND NOT the synchronous detection circuit 6, the signals are synchronously detected. At the same time, at the output of the synchronous detection circuit 6, signals are generated that block the passage of the pulse signals of the reset circuit 7 and transmitted to the fourth input of the control and memory circuit 2 — the R-input of the second binary counter, by which counting pulses are recorded to generate a smoke registration signal.

At the same time, the obtained values of the converted reflected signals of the main 4 and additional 5 receivers are sequentially converted by the determinant 8 of the ratios of changes in the scattering intensity (Fig. 1, the implementation example in Fig. 7), into the ratio of the current changes in the corresponding values of the received and converted reflected signals between the signals of the main 4 and additional 5 receivers (Fig. 1), synchronous to the emitted light pulses. When receiving a sequence of reflected light pulsed signals by the main 4 and additional 5 receivers at the output of the determinant 8, the ratios of changes in the scattering intensity determine the change in the scattering intensity of the reflected signals by the ratio of the current changes in the scattered light intensity of the reflected signals that are synchronous to the emitted light pulses of the emitter 3. How many times the intensity change scattering across the particle diameter with linear polarization scattering of the main receiver is changed from the scattering (diffraction) distributed on the particles in the screen (optical camera).

The obtained ratio of the values of the signals of the intensity of scattering of light radiation is simultaneously compared with the specified second upper and third lower threshold signal values by the identifier 9 of the scattering of light radiation (Fig. 1, an example implementation in Fig. 8). Moreover, the second upper and third lower threshold values of the signals are determined in proportion to the intensity of scattering of light radiation on the particles of the corresponding combustion products and are selected in accordance with the scattering coefficients of the suspended particles in the recorded air aerosol, for example, according to the graphs of the dependence of the radiation scattering intensity shown in FIG. 10.

If the signal values of the obtained ratios (determinant of 8 ratios of changes in the scattering intensity) while simultaneously comparing with the second and third threshold values (identifier of light scattering 9) correspond to the signal values within the interval of the specified second upper and third lower threshold values, then the information signal synchronization circuit 10 ( Fig. 1) during the accumulation of a given number of counting pulses at the second output of the control and memory circuit 2, the second binary counter (f g 1) forming initiate registration signal at the output of smoke generator 11 (FIG. 1, FIG. 9), which is associated with the central hub of fire protection (Fig. not shown).

If the signal values of the obtained ratios (determinant of 8 ratios of changes in the scattering intensity) while simultaneously comparing with the second and third threshold values (identifier of light scattering 9) correspond to the values of the signals outside the interval of the specified second upper and third lower threshold values, then the information signal synchronization circuit 10, (Fig. 1) during the accumulation of a given number of counting pulses at the third output of the control and memory circuit 2 — the third binary counter ( Fig. 1), initiate the formation of a technological control signal at the output of the shaper 11 (Fig. 1, Fig. 9), while the output of the shaper 11 is connected to the central fire protection concentrator (not shown in Fig.).

The inventive method for detecting smoke can be implemented by a device that can be performed, for example, as shown in FIG. 1, 2-9, of the known components:

clock generator 1 (Fig. 1, Fig. 2), made on two NAND gates DD1.1, DD1.2, resistors R1, R2, R3, capacitances C1, C2, and R3, C1 - a time delay is formed by the circuit clock pulses at the second output of the clock generator 1 at 45-50 μs compared with the first output;

control and memory circuit 2 (Fig. 1) performed on three binary counters - the first DD2.2, the second DD2.1 and the third DD3.1, with the V-input and R-input of each of them being sequentially the first and second, third and its fourth, fifth and sixth inputs, and the given output of each binary counter are its corresponding outputs, while the first and second inputs of circuit 2, respectively, the V-input and R-input of the first binary counter DD2.2, are associated with the corresponding clock outputs generator 1, and the first output is the output of the first binary counter DD2.2, connected with the input of the emitter 3, the third input of circuit 2 - the V-input of the second binary counter DD2.1, and the first input of synchronous detection circuit 6 - with an RC circuit (Fig. 1), the fourth and fifth inputs of circuit 2, respectively - R-input the second (DD2.1) and V-input of the third (DD3.1) binary counters are connected to the first output of the information signal synchronization circuit 10, the second output of the circuit 2 being connected to the C-inputs of the first (DD2.2) and second (DD2. 1) its binary counters and the first input of the shaper 11, the sixth input of circuit 2 is the R-input of the third binary counter DD3.1, connected to the second output ohm of the circuit 10 synchronization of the information signal, and the third output of circuit 2, connected to the C-input of its third binary counter DD3.1, is connected to the second input of the shaper 11;

emitter 3 (Fig. 3), made on transistors VT1, VT2, LED VD3, resistors R5, R6, which convert the pulse sequence from the first output of the control and memory circuit 2 - the first binary counter DD2.2, into light pulses of a given duration and emit them into an optical camera with light-absorbing walls (not shown in Fig.), is optically connected to the inputs of the main 4 and additional 5 receivers (Fig. 1), which simultaneously receive reflected light pulses by the main 4 at an angle different from the optical axis of radiation a receiver and an additional 5 receiver located in the side scattering zone relative to the optical axis of the light pulse emission;

the main 4 and additional 5 receivers (Fig. 1, Fig. 4) of the reflected light signals, each of which is made with an amplifier covered by a negative feedback loop (R14) at a constant voltage for resistance to changes in ambient temperature in the range from -25 to + 60 ° C on VT7, VT8 - transistors, UD1 - a photodiode, multi-stage RC filter - R7C4, R8R9, C5R11R10C6, R15R16C7, which excludes the occurrence of pulsed noise in the power supply, with their inputs are optically coupled to emitter 3 (Fig. 1), while the output of the main 4 receivers connected to the second input of circuit 6 synchronous detection and the first input of the determinant 8 ratios of changes in the scattering intensity, and the output of the additional 5 receiver is associated with its second input;

synchronous detection circuit 6 (Fig. 1, Fig. 5) containing two logical elements AND NOT DD1.3, DD1.4, a limiting diode VD2, R17C8 - circuit, and the second input of circuit 6 is connected to the inputs of the first logical element And NOT, and its output is through a diode with an RC circuit, which is connected through a capacitor to the first input of circuit 6 and the input of the second logical element AND NOT, the other input of which is connected to the third input of circuit 6 and the output of reset circuit 7 (Fig. 1) , while the output of the second logical element AND is NOT with the output of circuit 6, associated with the input of circuit 10 synchronization information signal;

a reset circuit 7 (Fig. 1, Fig. 7) made on the transistor VT9, resistors R18, R19, R20, connected by an output to the third input of the synchronous detection circuit 6 (Fig. 1);

determinant of 8 ratios of changes in the scattering intensity (Fig. 1, the implementation example in Fig. 7), performed on well-known elements industrially produced by domestic manufacturers - three operational amplifiers ОУ3, ОУ4, ОУ5, three transistors VT10, VT11, VT12 and four resistors R25, R26 , R27, R28, associated with the corresponding outputs of the main 4 and additional 5 receivers, and the output is with the input of the identifier 9 of the scattering of light radiation. The signals from the output of the main 4 receiver are transmitted to the first input of the determinant 8 and subjected to its logarithm on the elements ОУ3, VT10 and R25, at the same time, the signals from the output of the additional 5 receiver are transmitted to the second input of the determinant 8, which are logarithm on the elements ОУ4, VT11 and R26 and then determine the relationship between the logarithmic signals of the main 4 receiver and the logarithmic signals from the additional 5 receiver, and on the elements ОУ5, VT12 and R27 perform the inverse logarithm (anti-logarithm), determine the ratio of the variation in the scattering intensity;

light scattering identifier 9 (Fig. 1, the implementation example in Fig. 8), made on two operational amplifiers ОУ1, ОУ5, eight resistors R25, R26, R31, R32, R33, R34, R35, R36 and AND-NOT logic associated with the output of the determinant 8 of the ratio of the variation of the scattering intensity and the input of the circuit 10 synchronization of the information signal. Resistors R32, R31 and R33, R36 are voltage dividers that specify the second upper and third lower threshold values. The signals coming from the output of the determinant 8 of the ratio of changes in the scattering intensity through the element R29 go to the direct input of the operational amplifier - the element ОУ1, and through the element R33 - to the inverse input of the operational amplifier - the element ОУ2. The signals from the outputs of the voltage dividers - elements R31, R32 and R35, R36, are transmitted to the inverse input of the operational amplifier - element ОУ1, and the direct input of the operational amplifier - element ОУ2. Identifier 9 with operational amplifiers - elements ОУ1 and ОУ2, works in such a way that if the signal at the direct input of the operational amplifier is greater than the signal at its inverse input, then the output will be converted into a “logical unit”, and if the signal is at the direct input of the operational If the amplifier is smaller than the signal at its inverse input, then the output signal will be converted into a "logical zero". If at each output of operational amplifiers - elements ОУ1 and ОУ2, as a result of the conversion there will be “logical units”, the result is identified as an information signal for smoke detection, and with subsequent conversion by the AND-NOT element, at the output of identifier 9, the signal will be converted into a “logical zero. " If at one of the outputs of operational amplifiers - elements ОУ1 and ОУ2, the signal will be converted as a “logical zero”, then the result is identified as an information signal of the absence of smoke, and with subsequent conversion by the AND-NOT element, at the output of identifier 9, the signal will be converted as “Logical unit”;

an information signal synchronization circuit 10 (Fig. 1) made on sequentially connected logical elements OR-NOT, the first AND-NOT and the second AND-NOT, and the inputs of the OR-NOT elements are inputs of the circuit 10, which are connected by one input to the output of the circuit 6 and the other with the release of the identifier 9 of the scattering of light radiation. The outputs of the elements AND are NOT the first and second outputs of the circuit 10, while the first output of the circuit 10 is connected to the R-input of the second binary counter DD2.1 and the V-input of the third binary counter DD3.1 of the control and memory circuit 2, and the second output of the circuit 10 is connected to the R-input of the third binary counter DD3.1 of the control and memory circuit 2;

shaper 11 (Fig. 1, Fig. 9), made on transistors VT13, VT14, resistors R37, R38, R39, R40, the inputs of which are connected respectively to the second output (second output of the binary counter DD2.1) and the third output (third output binary counter DD3.1) control and memory circuit 2, and the outputs are connected to the central fire protection concentrator (not shown in Fig.).

The device operates as follows:

Clock generator 1 produces rectangular pulses with a period of about 1 s. The circuit R3, C1 forms a time delay at the second output of generator 1 (DD1.2), on which the pulse appears 45-50 μs after it appears on the first output (DD1.1). The pulses from the clock generator 1 are transmitted to the first input of the control and memory circuit 2, the V-input of the first binary counter DD2.2, at the first output of which a positive pulse appears with a duration of the order of 45 μs, which determines the time of emission of light pulses by the emitter 3 emitted in an optical camera with light-absorbing walls (not shown in Fig.).

The reflected light pulses arriving at an angle different from the optical axis of the radiation are simultaneously received by the main 4 receiver (Fig. 1, an implementation example in Fig. 4) and an additional 5 receiver located in the lateral scattering zone relative to the optical axis of the radiation of light pulses (Fig. 1, implementation example in Fig. 4), and then the received reflected signals are converted into electrical signals. Simultaneously with the sequence for converting electrical signals to light emitter 3 (Fig. 1) form a synchronous periodic sequence of counting pulses to the third input of the control and memory circuit 2 - V-input of the second binary counter of the circuit (Fig. 1), for the formation of the RC circuit circuit 6 synchronous detection (Fig. 1, an example implementation in Fig. 5) of the enable signal with a duration of about 25 μs, determining the beginning of the period for the accumulation and counting of the number of counting pulses of a given periodic sequence awns synchronous respective light pulse and which, via synchronizing circuit 10 is supplied to the fourth input of the control circuit 2, and memory - R-input of the second binary counter (. Figure 1) is zeroed its second binary counter in the absence of reception of the reflected signal 4 main receiver. For each radiation pulse by the emitter 3 by the control and memory circuit 2 — its second binary counter DD2.1 is counted to “1” (pulses from its first output — the output of the first binary counter DD2.2, go to the counting V-input of the second binary counter DD2 .1) and discarded.

The reset pulses of the circuit 7 in the absence of received reflected signals by the main 4 receivers through the synchronization circuit 10 reset the second binary counter DD2.1 from the control and storage circuit 2.

The received and converted reflected light pulses of the main 4 receiver, which are fed to the second input of the synchronous detection circuit 6 and then to the first input of its second NAND gate, provide the level of a “logical unit”. In this case, the reset pulses from the circuit 7 do not pass to the first input of the information signal synchronization circuit 10. Simultaneously, the incoming signals from the main 4 and additional 5 receivers to the first and second inputs, respectively, of the determinant 8 of the ratio of changes in the intensity of scattering of light radiation are converted to determine changes in the results of the ratios corresponding to the values of the synchronously received reflected signals of the main and additional receiver.

The signals from the output of the main 4 receiver are transmitted to the first input of the determinant 8 and are logarithmed on its elements ОУ3, VT10 and R25, at the same time, the signals from the output of the additional 5 receiver are transmitted to the second input of the determinant 8, which are logarithmed on the elements ОУ4, VT11 and R26 and then the relationships between the logarithmic signals of the main 4 receiver and the logarithmic signals from the additional 5 receiver are determined, and on the elements ОУ5, VT12 and R27, the inverse logarithm of the obtained values is performed with signal ratio, determining changes in scattering intensity.

The signals from the determinant 8 of the ratio of changes in the scattering intensity of the signals of the ratios are simultaneously compared with the specified second upper and third lower threshold signal values by the scattering identifier 9 of the light radiation (Fig. 1, the implementation example in Fig. 8), namely, through the resistor element R29 come to the direct input of the operational amplifier - element ОУ1, and through the resistor - element R33, - to the inverse input of the operational amplifier - element ОУ2. The signals from the outputs of the voltage dividers - elements R31, R32 and R35, R36, are transmitted to the inverse input of the operational amplifier - element ОУ1, and the direct input of the operational amplifier - element ОУ2, respectively. Identifier 9 with operational amplifiers - elements ОУ1 and ОУ2, works this way: if the signal at the direct input of the operational amplifier is more than the signal at its inverse, then the output is converted into a “logical unit”. In the case when the signal at the direct input of the operational amplifier is less than the signal at its inverse input, then the signal will be converted as a “logical zero” at the output. If at each output of operational amplifiers - elements ОУ1 and ОУ2, as a result of the conversion there will be “logical units”, the result is identified as an information signal for smoke detection, and with subsequent conversion by the AND-NOT element, at the output of identifier 9, the signal will be converted into a “logical zero. " If at one of the outputs of operational amplifiers - elements ОУ1 and ОУ2, the signal will be converted as a “logical zero”, then the result is identified as an information signal of the absence of smoke, and with subsequent conversion by the AND-NOT element, at the output of identifier 9, the signal will be converted as "Logical unit."

The signal of the "logical unit" from the output of the identifier 9 of the scattering of light radiation is transmitted to the second input of the circuit 10 synchronization of the information signal. When the "logical units" appear on the first and second inputs of the information signal synchronization circuit 10, a logic zero signal is generated at its output, which is transmitted to the fourth input of the control and memory circuit 2 — the R-input of the second binary counter DD2.1, and - its fifth input is the V-input of the third binary counter DD3.1. The reset pulse of circuit 7 appears after the end of the radiation pulse of the emitter 3 and coincides in time with the received signal of the main 4 receiver, because the latter is delayed due to the inertia of its photodiode VD1.

When smoke occurs by the control and storing circuit 2 — the second binary counter DD2.1, a “count” is performed for about 4 seconds, in which, upon the arrival of the fourth pulse to the third input of the control and storing circuit 2, it is formed at its second output, the output of the second binary counter DD2.1 (the third pin of the binary counter chip) the level of the "logical unit" that blocks the C-input of the first binary counter DD2.2, and then goes to the first input of the shaper 11 of the smoke registration signal, the device goes into "fire" mode. In this case, the third binary counter DD3.1 of the control and memory circuit 2 is reset to the first input of the shaper 11

In the absence of signals at the inputs of the shaper 11 of the smoke registration signal or the process control signal, the device exits the “fire” mode and goes into standby mode. If dust detection zone - measuring chamber (not shown) contains dust particles, steam, etc., then the received reflected light signals are converted into electrical signals by the main 4 receiver and transmitted to the second input of the synchronous detection circuit 6 - to the input of its first logical element AND NOT, providing the signal level of the "logical unit". Since the reset pulses from the circuit 7 do not pass, then at the first input of the information signal synchronization circuit 10 there will be a “logical unit” signal.

Simultaneously, the incoming signals from the main 4 and additional 5 receivers to the determinant 8 of the ratio of changes in the intensity of scattering of light radiation are transmitted from its output to the identifier 9 of scattering of light radiation, from the output of which the "logical zero" signal is fed to the second input of the information signal synchronization circuit 10. When a "logical zero" occurs at the first and / or second inputs of the information signal synchronization circuit 10, a signal level "logical unit" is generated at its output, which is fed to the fourth input of the control and memory circuit 2 — the R-input of the second binary counter DD2.1, and - at its fifth input - the V-input of the third binary counter DD3.1. Scheme 2 control and memorization - the third binary counter DD3.1 performed "count". The reset pulse of circuit 7 appears after the end of the radiation pulse of the emitter 3 and coincides in time and coincides in time with the received signal of the main 4 receiver, because the latter is delayed due to the inertia of its photodiode VD1. The second binary counter DD2.1 of the control and memory circuit 2 is reset at this time.

When particles of dust, steam, etc. control and memory circuit 2 — by the third binary counter DD3.1, a “count” is performed for about 4 seconds, which, upon the arrival of the fourth pulse at its third output — the output of the third binary counter DD3.1 (third pin of the binary counter chip), the level appears logical unit, which blocks the C-input of the third binary counter DD3.1, and enters the second input of the shaper 11 of the process control signal, and the device switches to the "control" mode. In the absence of signals at the inputs of the shaper 11 of the smoke registration signal or the process control signal, the device exits the “control” mode and goes into standby mode.

The inventive method of detecting smoke and a device for its implementation with high reliability provides an alarm regardless of the nature of smoldering or burning material, they are resistant to false alarms, by eliminating dust factors and false alarms with the formation of technological control signals.

Claims (3)

1. The method of detecting smoke, which consists in the formation of synchronous periodic sequences of counting pulses and emitted into the optical camera with light-absorbing walls of light pulses, the main receiver receiving the reflected light pulses arriving at an angle different from the optical axis of radiation, converting them into electrical signals, followed by synchronous detecting and comparing with a threshold value, determining from the signals of reflected light pulses exceeding the threshold value, the beginning period for the accumulation and counting of the number of counting pulses synchronous to the corresponding light pulses, the formation of a smoke registration signal during the accumulation of a given number of counting pulses, characterized in that they simultaneously form the reception and conversion of reflected light pulses by an additional receiver located at an angle different from the optical axis of radiation in zone of lateral scattering relative to the optical axis of radiation, and during the accumulation of a given number of counting pulses, determine the ratio solving current changes in the corresponding values of the received and converted reflected signals between the main and additional reflected receivers, followed by a simultaneous comparison of the signals of each ratio of the received reflected signals of the main and additional receivers with the specified second upper and third lower threshold signal values, which are determined in proportion to the light scattering intensity by particles whose linear dimensions are equivalent to the corresponding burning products I, wherein the smoke detection signal is formed at the coincidence of said signal values with ratios of signal values corresponding to the values of signals within the predetermined interval of the second upper and lower threshold values of the third accumulation period into a predetermined number of counting pulses, and if their difference signal forming process control. 2. A smoke detection device comprising a clock generator connected by respective outputs to the first and second inputs of a control and memory circuit made on three binary counters — first, second and third, with the V input and R input of each of them being sequentially the first and its second, third and fourth, fifth and sixth inputs, and the given output of each binary counter are its corresponding outputs, while its second output is connected to the C-inputs of its first and second binary counters, and the third output is connected to C-input the house of its third binary counter, and the first output of the first binary counter is connected to its third input of the second binary counter, the first input of the synchronous detection circuit and the emitter connected through the optical camera with light-absorbing walls to the main receiver of the reflected signals, the output of which is connected to the second input of the synchronous circuit detection associated with the third input with a reset circuit, a shaper, characterized in that it contains an additional optically coupled to the emitter an additional receiver of reflected signals the output, which is connected to the input of the determinant of the ratios of changes in the scattering intensity associated with the other input to the output of the main receiver, and the output, through the light scattering identifier, to the input of the synchronization circuit, the first input of which is connected to the output of the synchronous detection circuit, while the first output of the circuit synchronization is connected with the fourth and fifth inputs of the control and storage circuits, and the second output is connected with the sixth input of the control and storage circuits, the second and third outputs of which are connected with tvetstvuyuschimi driver inputs. 3. The smoke detection device of claim 2, characterized in that the determinant of the ratios of changes in the scattering intensity is implemented in the form of logarithmators connected to its inputs, each of which is made on an operational amplifier with a transistor in negative feedback, and their outputs are connected through a divider with an anti-logarithm made on a transistor with an emitter input, to the collector of which a resistor and a third operational amplifier are connected in parallel, connected by the output of the determinant of the ratios of changes in scattering intensities.

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