Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Referring to FIG. 1, the invention provides a labyrinth optimization design and dust pollution resistance method for a smoke sensor, which comprises the following steps of step1, transmitting and receiving a first wave band signal and a second wave band signal to an air detection area through a signal transmitting device so as to detect fusion particles of smoke and dust and vapor particles.
The signal transmitting device specifically comprises an LED1 and an LED2 which adopt different wavelengths to respectively transmit optical signals of a first wave band and a second wave band, and a double-channel signal processing circuit is configured to respectively receive reflected signals from the LED1 and the LED 2.
In a preferred embodiment, the first and second band signals are transmitted to and received from the air detection region, specifically, fused particles of smoke and dust are detected by the first band optical signal.
And detecting the water vapor particles through the second band optical signal.
The first wavelength band is typically chosen to be shorter (e.g., blue or ultraviolet) because of the strong scattering effect of these wavelengths on smoke and dust particles. The size of the smoke and dust particles is typically small (micron-sized), and is more sensitive to scattering of short wavelength light.
The second band of wavelengths is typically chosen to be longer (e.g., red or infrared light) because the absorption and scattering properties of the vapor particles are more pronounced for these wavelengths of light. The water vapor particles absorb long wavelength light strongly, and their size distribution and optical properties are different from those of smoke and dust.
Step2, based on the second wave band signal, the detection precision of the smoke sensor is adjusted.
In a preferred embodiment, the smoke sensor detection accuracy adjustment based on the second band signal includes comparing the second band signal with a preset band signal threshold, and uploading the weather environment humidity through the cloud network when the second band signal is higher than the preset band signal threshold.
The method comprises the steps of matching the meteorological environment humidity in a preset humidity-alarm parameter mapping table to obtain alarm precision limiting data of a corresponding smoke sensor in an air detection area, wherein the alarm precision limiting data comprise an alarm timing frequency threshold value and an alarm delay time, the alarm precision limiting data are used for mapping the precision state of a smoke detector, and the alarm precision limiting data are reasonably set according to specific application scenes, so that the sensitivity and the anti-interference capability of the detector are balanced, and the optimal detector performance is realized.
The humidity-alarm parameter mapping table comprises meteorological environment humidity and alarm precision limiting data, the humidity-alarm parameter mapping table is used for representing mapping relations between different meteorological environment humidity and alarm precision limiting data, and the data of the humidity-alarm parameter mapping table are as follows:
TABLE 1 mapping table of humidity to alarm parameters
Specifically, the second band signal is used for detecting the water vapor particles, the intensity of the second band signal is related to the ambient humidity, and whether the current ambient humidity is abnormal can be judged by comparing the preset intensity signal. And the meteorological environment humidity is uploaded to the cloud, so that centralized management and analysis of data can be realized, and the smoke sensor can be regulated and controlled uniformly. The adaptability and the reliability of the smoke sensor under different humidity environments can be improved according to the limitation data of the humidity adjustment alarm precision of the meteorological environment.
Because the detection accuracy of the smoke sensor is interfered by water vapor particles generated by air humidity, when the light signals generated by water vapor are identified, the alarm delay time is required to be increased and the alarm threshold value is required to be improved so as to achieve the water mist and water vapor false alarm resistance.
According to the invention, the smoke alarm precision limiting data is adjusted by detecting the ambient humidity, so that the smoke alarm triggered by water vapor particles by mistake is weakened.
Step3, processing the first wave band signal by adopting a differential signal processing technology, distinguishing fusion particles for identifying smoke and dust, and introducing the fusion particles into the labyrinth measuring cavity.
Referring to fig. 2, in a preferred embodiment, the labyrinth measuring chamber includes a moisture adsorption device, an air flow control device, a smoke channel 1 and a dust channel 2.
The water vapor adsorption device is used for screening out water vapor particles.
Specifically, the water vapor adsorption device can adopt a water vapor guide plate of a physical adsorption material (such as silica gel, molecular sieve and the like) or a chemical adsorption material (such as calcium chloride and the like), and is arranged in the inlet 4 or the channel of the labyrinth measuring cavity, and the materials can efficiently adsorb water vapor and have no interference to the detection of smoke and dust, so that the water vapor is ensured to be effectively adsorbed before entering a detection area.
The detection precision of smog and dust can be disturbed to steam granule, especially in high humidity environment, can effectively reduce the interference of steam to testing result through steam adsorption equipment, improves the accuracy of sensor.
The air flow control device is used for leading the smoke particles into or out of the smoke channel 1 from the inlet 4 on one side and leading the dust particles into or out of the dust channel 2 from the inlet 4 on the other side.
The smoke channel 1 is used for collecting smoke particles.
The dust channel 2 is used for collecting dust particles.
In a further preferred embodiment, the differential signal processing technology is adopted to process the first band signal, the fusion particles of the smoke and the dust are distinguished and identified, and the fusion particles are introduced into the labyrinth measuring cavity, specifically, B1, the differential signal processing technology is adopted to process the first band signal, so as to determine the signal reflection intensity of the smoke particles and the dust particles, and reflect the concentration of the smoke particles and the concentration of the dust particles in the air detection area.
Differential signal processing techniques are methods of extracting useful information based on differences between signals. In its simplest form, it involves a subtraction operation of two related signals, typically measurements of the same physical quantity under different conditions, or from measurements of different but related physical phenomena. For smoke particles and dust particles, there are significant differences in the frequency, amplitude, phase, etc. of the signals, so that the smoke particles and the dust particles can be distinguished by differential signal processing techniques.
And B2, respectively determining low-speed air flow and high-speed air flow in the labyrinth measuring cavity according to the signal reflection intensity of the smoke particles and the dust particles.
Where smoke particles are typically small and light, with low signal reflection intensity (e.g. 1-100 relative units), a slow air flow rate (e.g. 0.1-1 m/s) is typically required to effectively capture and measure these particles to prevent particles from bypassing the sensor due to too fast an air flow, dust particles are larger and heavier than smoke particles with high signal reflection intensity (e.g. 100-1000 relative units), and due to their high weight a fast air flow rate (e.g. 1-10 m/s) may be required to ensure that they can be transported to the detection area without settling.
In actual measurement, calibration and optimization are required according to factors such as light source wavelength, particle concentration, detector sensitivity, environmental conditions and the like, so as to ensure the accuracy of measurement results.
And B3, generating an air flow control instruction of an air flow control device according to the low-speed air flow and the high-speed air flow, and introducing particles through the air flow control device.
Specifically, a baffle may be disposed at the detector inlet 4 to divide the air flow into two parts, namely a low speed and a high speed. According to the physical characteristic difference of the smoke particles and the dust particles, the smoke particles can be carried into the smoke channel 1 by the low-speed air flow, and the dust particles can be carried into the dust channel 2 by the high-speed air flow. The smoke particles are generally small in particle size (0.0-1 micron), light in weight, easy to move along with the airflow, small in inertia and capable of entering the smoke channel 1 along with the low-speed airflow, and the dust particles are generally large in particle size (1-100 microns), heavy in weight, large in inertia and difficult to change direction along with the airflow, so that the dust particles can follow the high-speed airflow area and finally enter the dust channel 2.
Step4, measuring the smoke concentration and the dust concentration in the labyrinth measuring cavity through an optical detection device.
In a preferred embodiment, the smoke concentration and the dust concentration are measured by an optical detection device in the labyrinth measuring cavity, and the content comprises that the optical signal intensity of the smoke particles and the dust particles corresponding to the smoke channel 1 and the dust channel 2 is measured by the optical detection device in the labyrinth measuring cavity and is compared with the signal reflection intensity of the smoke particles and the dust particles so as to determine the guiding deviation coefficient of the smoke channel 1 and the guiding deviation coefficient of the dust channel 2.
The guiding deviation coefficient of the smoke channel 1 is used for reflecting the interference of the smoke channel 1 on the detection of the smoke particles due to the existence of the dust particles, and the guiding deviation coefficient of the dust channel 2 is used for reflecting the interference of the dust channel 2 on the detection of the dust particles due to the existence of the smoke particles.
On the one hand, in a complex airflow environment, the movement track of the smoke particles is more easily influenced by airflow disturbance due to light weight, and the smoke particles are difficult to stably enter the smoke channel 1 along an expected path of gravity, while the dust particles are relatively less influenced by airflow, but can also deviate from a settling path guided by gravity to enter an error channel under strong airflow impact. On the other hand, the dust particles are easy to agglomerate, the volume and the mass of the agglomerated particles are increased, the sedimentation characteristics of the agglomerated particles are changed, and partial dust which originally enters the smoke channel 1 according to the characteristics of small particles possibly enters the dust channel 2 due to agglomeration, so that guiding deviation is caused. Meanwhile, smoke particles can be agglomerated under specific conditions, and the smoke particles can be influenced to accurately enter the corresponding channels according to gravity difference.
Guide deviation coefficient in smoke channel 1The concentration of the dust particles entering is corrected downwards to generate the smoke concentration of the smoke channel 1I.e.,For the optical signal intensity of the smoke particles in the smoke channel 1,For converting the optical signal intensity into a smoke particle concentration value, e.g. determined experimentally, for a smoke concentration at a corresponding unit optical signal intensity of predetermined smoke particlesThe content of the acid in the solution is 0.1,For correcting measured data of smoke particles to be more closely related to true values, e.g. for a predetermined smoke concentration offsetAt 0.05, the smoke concentration generation data for the smoke channel 1 is as follows:
TABLE 2 exemplary Table of Smoke concentration Generation data for Smoke channels
Guide deviation coefficient in dust channel 2The concentration of the smoke particles entering is corrected downwards to generate the dust concentration of the dust channel 2I.e.,For the optical signal intensity of the dust particles in the dust channel 2,The dust concentration of the preset dust particles under the corresponding unit optical signal intensity is used for converting the optical signal intensity into a dust particle concentration value, and is determined through experiments,For the preset dust concentration offset, the measurement data of the dust particles are corrected to be closer to the true value.
Analysis of dust concentration helps to assess the air quality of the smoke detection environment. Dust is similar to smoke particles in physical properties and behavior, and high concentrations of dust can interfere with the operation of the smoke detector, resulting in false positives or false negatives. By monitoring the dust concentration of the smoke detection environment, the sensitivity of the detector can be adjusted or measures can be taken to reduce the influence of dust on the detector, so that the accuracy and reliability of smoke detection are improved.
In a further preferred embodiment, the coefficient of guiding deviation of the smoke channel 1 is derived by dividing the optical signal intensity of the smoke particles in the dust channel 2 by the optical signal intensity of the smoke particles in the smoke channel 1.
The guide deviation coefficient is ideally 0, indicating that all smoke particles have entered the smoke channel 1. In practice the guiding deviation coefficient is greater than 0, indicating that part of the smoke particles has entered the dust channel 2.
The guiding deviation coefficient of the dust channel 2 is obtained by dividing the optical signal intensity of the dust particles in the dust channel 1 by the optical signal intensity of the dust particles in the dust channel 2.
Step5, automatically adjusting the width of the labyrinth channel in the labyrinth measuring cavity according to the smoke concentration to divide the space of smoke particles and dust particles.
In a preferred embodiment, the method for automatically adjusting the width of the labyrinth channel in the labyrinth measuring cavity according to the smoke concentration to space-divide the smoke particles and the dust particles comprises the steps of comparing the smoke concentration with the dust concentration to obtain the concentration ratio of the smoke particles compared with the dust particles, and mapping the concentration ratio of the smoke particles to the space ratio of the smoke channel 1.
And controlling the width of the labyrinth channel in the labyrinth measuring cavity according to the space occupation ratio of the smoke channel 1 so as to realize the space division of smoke particles and dust particles.
Specifically, in order to enable the width of the labyrinth passage in the labyrinth measuring cavity to be freely changed to generate a partition space, a movable baffle plate 3 can be arranged in the labyrinth measuring cavity, so that the labyrinth measuring cavity is beneficial to dynamically introducing proper smoke quantity, and dust particles are prevented from interfering smoke detection and identification, so that a smoke detection result is more accurate.
The width of the labyrinth channel in the labyrinth measuring cavity refers to the width of the opening and closing position of the movable baffle 3, the total length of the width of the labyrinth channel is a fixed value, for example, 10mm, and the data of the width of the labyrinth channel in the labyrinth measuring cavity are exemplified as follows:
TABLE 3 maze measuring cavity maze channel width exemplary Table
The concentration ratio of the smoke particles compared with the dust particles is calculated in a way of [ smoke concentration/(smoke concentration+dust concentration) ], namely 100%, representing the proportion of the smoke particles relative to the total particles (smoke+dust).
According to the invention, the water vapor particles are removed through screening, the width of the labyrinth channel is automatically adjusted according to the smoke concentration, smoke and dust are respectively introduced into the channels in the labyrinth measuring cavity, so that the space division of the smoke particles and the dust particles is realized, the detector can stably work in a complex environment with high humidity and multiple dust, and the adaptability of the detector is increased. Meanwhile, the smoke concentration and the dust concentration are measured through the optical detection device, so that the stability and the accuracy of detection are enhanced.
Step6, carrying out fire early warning judgment on the smoke concentration in the labyrinth measuring cavity, and starting a cleaning device additionally arranged in the labyrinth measuring cavity according to the smoke concentration and the dust concentration to carry out cleaning treatment.
Referring to fig. 3, in a preferred embodiment, the method for performing fire early warning judgment on the smoke concentration in the labyrinth measurement cavity includes obtaining the smoke concentration in the smoke channel 1, and judging whether the smoke concentration of the smoke channel 1 in the labyrinth measurement cavity reaches a fire early warning standard according to a preset smoke concentration judgment model.
And carrying out fire early warning when the smoke concentration of the smoke channel 1 in the labyrinth measuring cavity reaches the fire early warning standard.
Specifically, the predetermined smoke concentration determination model is as followsWhereinA smoke concentration determination result instruction of the smoke channel 1 in the maze measuring cavity is represented,Representing the smoke concentration of the smoke channel 1,The smoke concentration representing the smoke channel 1 corresponds to a preset threshold value, which, by empirical development,Indicating that the smoke concentration of the smoke channel 1 in the labyrinth measuring cavity does not reach the fire early warning standard,The smoke concentration of the smoke channel 1 in the maze measuring cavity reaches the fire early warning standard.
In a further preferred embodiment, the cleaning device additionally arranged in the labyrinth measuring cavity is started for cleaning according to the smoke concentration and the dust concentration, specifically, the cleaning device and the air flow control device are installed in a linkage mode, after fire early warning judgment is finished, the air flow control device is used for leading out the particles in the smoke channel 1 and the dust channel 2, and meanwhile, the particle retention in each channel is detected.
The particle retention refers to the concentration of residual smoke particles or residual dust particles after the air flow in the channel is led out.
The cleaning device is started to perform cleaning treatment when at least one of the accumulation amounts of particles in the smoke passage 1 and the dust passage 2 exceeds a preset accumulation amount.
Specifically, the cleaning device is respectively connected with the smoke channel 1 and the dust channel 2, so that the cleaning device can independently clean different channels, for example, when the accumulation amount of particles in the smoke channel 1 exceeds the preset accumulation amount, the cleaning device is started to clean the particles in the smoke channel 1.
According to the invention, the cleaning device additionally arranged in the labyrinth measuring cavity is started to perform cleaning treatment according to the smoke concentration and the dust concentration, so that the labyrinth measuring cavity is automatically cleaned, and the continuity and the accuracy of detection are ensured.
In a further preferred embodiment, the smoke sensor maze optimization design and dust pollution resistance method further comprises the step of alternately detecting the signals of the LEDs 1 and the LEDs 2 in the standby state of the smoke sensor based on a time division multiplexing technology so as to realize energy-saving operation.
The basic idea of the time division multiplexing technology is to divide the time of a channel into a plurality of time slices, each time slice is used for transmitting data of a different signal source, and only one signal source occupies the channel for data transmission in a specific time period. In the case of two LEDs used in a smoke sensor, each LED may be illuminated by assigning different time periods so that only one LED is in an active state at a time and the other is in an off or low power state.
By time-sharing control of the operating states of the LEDs, only one LED is operating at any given time, thereby reducing the total energy consumption required to turn on all LEDs simultaneously, not only saving electrical energy, but also reducing thermal effects due to continuous high power operation, and contributing to an increase in device lifetime. Meanwhile, as only one LED is activated for measurement at a time, the interference between the LEDs is reduced, and the quality of signal detection is improved.
The working period of each LED can be dynamically adjusted according to actual needs by utilizing a time-sharing multiplexing technology. For example, in the case of lower smoke concentrations, the detection frequency may be reduced, further saving energy, while in highly sensitive areas where there may be a risk of fire, the detection frequency may be increased to ensure timely response.
The foregoing is merely illustrative and explanatory of the principles of this invention, as various modifications and additions may be made to the specific embodiments described, or similar arrangements may be substituted by those skilled in the art, without departing from the principles of this invention or beyond the scope of this invention as defined in the claims.