UA91922U - Multichannel smoke content detector - Google Patents

Abstract

A multichannel smoke content detector comprises emitters and photoreceivers arranged at different channels with different geometrical dimension. A temperature sensor and sensitive element of glass with sputtered gold layer are incorporated, and laser is used as emitter. An angle between incident and reflected optical radiation corresponds to plasmon resonance angle at presence of carbonic oxide molecules on the sensitive element.

Description

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Fig. 1

The proposed useful model belongs to smoke detectors and can be used to prevent fire in work, warehouse, hotel and office premises, as well as in railway and air transport.

Known optical sensors (1, 2) containing an optical module consisting of a light emitter, a light receiver and a measuring camera. In the presence of smoke, the radiation is scattered on the component particles of the smoke, and therefore the light receiver registers a reduced intensity of radiation.

Such sensors are compact, fast-acting, and consume a small amount of electrical energy.

Disadvantages of analogs include the fact that in the presence of dust, they give a false signal, because they do not distinguish dust particles from smoke particles.

The closest technical solution, accepted as a prototype, is the |Z)Y sensor, which implements multi-channels with different sizes of installation of radiation receivers according to the length of each channel. This allows to reduce the probability of false signals, but does not completely exclude the possibility of their occurrence.

The task of the proposed useful model is to create a smoke detector that can distinguish the smoke component from the dust component.

The task is solved by proposing a multi-channel smoke detector, which consists of emitters and photodetectors located in different channels with different geometric dimensions and differs in that it additionally includes a temperature sensor and a sensitive element made of glass with a sprayed layer of gold, and how a laser is used as the emitter, while the angle between the incident and reflected optical radiation corresponds to the plasmon resonance angle in the presence of carbon dioxide molecules on the sensitive element.

The proposed sensor is schematically depicted in fig. 1.

The sensor consists of semiconductor temperature sensors (1), diode emitters (2) and a laser radiation source (3), photodetectors that measure the intensity of scattering (9) and reflected radiation (7), a cylindrical lens with a metal layer sprayed on it (nanolayer thickness 50 nm gold or aluminum) (8), control and processing unit

From measured information (4), power supply unit (5) and detector (6). The smoke detector works as follows. When smoke appears in the working area, light scattering from the emitters (2) occurs on the smoke particles, which leads to the appearance of a signal at the output of the photodetectors (9), which fix the scattered light at different angles to the solid smoke particles.

The signal from the photodetectors (9) is sent to the control and processing unit of the measured information (4). To ensure the impossibility of false operation of the multi-channel detector, a sensitive element made of glass with a layer of conductive material sprayed on it (8) is additionally applied, which, due to the presence of the phenomenon of surface plasmon resonance, reacts to a greater extent to gaseous combustion products. At the same time, the angle of incidence of radiation from the source (3) and the angle of reflection on the photodetector (7) were chosen from previous studies of the sensitivity of plasmon resonance to gaseous combustion products. When, for example, carbon dioxide falls on a layer of conductive material (8), the intensity of the reflected light from the laser (3) changes, which changes the signal at the output of the photodetector (7), which is sent to the control unit and processing of the measured information (4). In addition, semiconductor temperature sensors (1) are installed, which respond to the increase in temperature in the measurement zone that accompanies ignition. The temperature change signal in the working area is also sent to the control unit and processing of the measured information (4). The detector is powered by block (5).

Information received from three physically distinct channels (the first channel based on the dependence of light scattering on solid smoke particles, the second channel based on the detected sensitivity of surface plasmon resonance to gaseous combustion products (Fig. 2) and the third temperature channel) is processed in block (4), which emits a fire alarm signal to the detector (b). In the case of dust, the signal will come only from the photodetectors (9), which will not be a sufficient condition for turning on the alarm system and transmitting a fire signal to the dispatcher.

An example of implementation

The implementation of the proposed technical solution was carried out on a working model according to the scheme shown in fig. 1. The layout consisted of three blocks: a temperature control block, an optical smoke control block, and a smoke control block using the phenomenon of surface plasmon resonance (SPR). The temperature control unit consisted of two highly sensitive small-sized semiconductor temperature sensors (1), which were developed at the Institute of Semiconductor Physics named after V.E. Lashkaryova of the National Academy of Sciences of Ukraine. The optical control unit consisted of two ALZO7A LEDs (2) located at angles of 45 and 25 degrees and two FD-24K photodetectors (9), which were located at the same angles to measure scattered light on smoke microparticles. The "PLAZMON-6" spectrometer, also developed at the Institute of Semiconductor Physics named after V.E.

Lashkaryova of the National Academy of Sciences of Ukraine. A semiconductor CaAv5 laser with a wavelength of 650 nm (3) was used as a source of p-polarized monochromatic light of the smog block on the PPR. The optical signal of reflected light from an optical lens with a metal layer sprayed on it (a 50-nm gold or aluminum nanolayer) (8) was converted into an electrical signal by the FD-2AK photoreceiver (7). The optical lens was made of optical silicate glass of the brand

FI with a refractive index of 1.61; first, a layer of chromium with a thickness of 2 to 8 nm was applied to the working face of the lens by thermal spraying in a vacuum, then a layer of gold with a thickness of 50 nm was applied to the chromium layer. The photodetector (7) and the semiconductor laser (3) were located at an angle of 43 degrees relative to the normal to the working surface of the lens (8), which corresponded to the conditions of excitation of the PIR. The control and registration unit (4) was assembled on a printed circuit board with software control and equipped with a power supply unit (5) and a sound and light signaling unit (b). To test the operation of the model, in a specially equipped room, artificially created conditions close to the conditions of the start of fire and smoke. These conditions were simulated by cigarette ignition and/or cotton ignition. Smoke caused the appearance of a signal at the outputs of all units. Artificial dusting of the room caused a signal only at the output of the optical smoke control unit. Thus, the working algorithm for block 4 adopted the condition of having at least two signals out of three at its input to turn on the sound and light alarm block (b). In this way, false activation of the smoke detector was prevented. In fig. 2. the kinetics of the appearance of signals at the output of the smog control unit on the surface plasma resonance is shown.

The positive effect of the proposed useful model is that the multi-channel smoke detector can distinguish between smoke and dust and therefore prevents false alarms.

The novelty of the proposed useful model is due to a combination of known and new features, which collectively create a new useful effect.

From the sources of information: 1. Limited Liability Company "UBEZH Group", Dyma alarm, patent of the Russian Federation Mo 2258259 pub. 10.08.2005 2. Limited Liability Company "Constructorskoe Bureau of Fire Automation", Smoke alarm, patent of the Russian Federation Mo 2317591, pub. 20.02.2008

Z. Horn V. Yu., Potetyunin S. V. Pozharnyi dymovoy izveshatel, patent Russian

Federation Mo 2417450, pub. 27.04.2011

Claims (1)

USEFUL MODEL FORMULA 40 Multi-channel smoke detector, which consists of emitters and photodetectors located in different channels with different geometric dimensions, which is distinguished by the fact that a temperature sensor and a sensitive element made of glass with a sputtered layer of gold are additionally introduced into it, and a laser is used as an emitter, with therefore, the angle between incident and reflected optical radiation corresponds to the angle of plasmon resonance when present on the sensitive 45 elements of carbon dioxide molecules.