RU2222803C2 - System of operative diagnostics of biological contamination of air in ventilation ducts of buildings and structures - Google Patents

Abstract

FIELD: environmental monitoring, proximate method of control over quality of air in ventilation ducts of buildings and structures for detection of finely divided organic powders and aerosols carrying pathogenic microorganisms dusted in them. SUBSTANCE: system includes optical fibers, beam splitters, inlet channels coupled to diagnostic center and meant for input of monochromatic radiation of laser into optical fibers to excite light signals of scattering and fluorescence in points of control in case of detection of dusted finely divided organic substances, exit channels intended for transportation of excited signals of scattering and fluorescence for their transmission to proper photodetectors of diagnostic center, unit making decision on basis of amplitude evaluation of received excited signals of scattering and integrated evaluation of received excited signals of fluorescence in fluorescence band and generating diagnostic signals of biological contamination of air in each point of control as DETECTED or NOT DETECTED. EFFECT: provision for operative diagnostics of biological contamination of air in assemblage of points of control in ventilation ducts of buildings and structures. 1 dwg

Description

 The invention relates to environmental monitoring and can be used in systems that carry out rapid control of air quality in the ventilation ducts of buildings and structures to identify sprayed fine organic powders and aerosols containing pathogenic microorganisms that are dangerous to humans.

 Currently, the need for air quality control in the ventilation ducts of buildings and structures, including express control in order to quickly detect bacteriological contamination, is becoming especially urgent in connection with the threats of using bacteriological weapons by terrorists. The fact is that existing ventilation systems, see for example [1], which are equipped with residential buildings, hotels, official institutions, commercial centers, as well as crowded places, for example metro rooms and tunnels, halls of large commercial, social and cultural sports centers, etc., are available for carrying out bacteriological attacks by attackers.

 At the same time, as the events of the fall of 2001 in the USA showed, the greatest danger is hidden infection of the airspace by spraying and dispersing finely dispersed organic powders and aerosols containing pathogenic microorganisms - bacteria, viruses, fungi, rickettsia, as well as microbial toxins that are extremely pathogenic severe infectious diseases (plague, anthrax, smallpox, glanders, etc.) with a fatal outcome. Since the damaging effect of biological weapons depends on the number of pathogenic microbes or toxins that enter the body, the task of quickly detecting traces of biological airborne contamination is vital. In this regard, the effectiveness of control in relation to many points become determining factors affecting the safety of the masses of people.

 The vast majority of air quality control methods to assess its gas composition and / or the presence of biological pollutants, including those hazardous to humans, are based on laboratory analysis of air samples. Moreover, in particular, when analyzing the composition of air, optical-radiometric methods [2] based on the use of a tunable laser, laser atomic fluorescence analysis methods [3], laser gas analyzers [4], [5] can be used. Diagnosis of pathogens of infectious and parasitic diseases can be carried out, for example, by analyzing appropriately prepared laboratory preparations based on air samples using luminescent microscopy [6]. In essence, the considered methods and means of analyzing air quality are closer to laboratory than to industrial ones, and with all their advantages (accuracy, reliability) cannot solve the problem of providing operational control with respect to many points, i.e. ineffective in solving practical problems arising from the threat of bioterrorism.

 Operational remote monitoring of the state of the air by such a specific parameter as dustiness, including monitoring dustiness of air in ventilation ducts, can be carried out using optical dust meters [7], operating on the principle of monitoring the transmitted light beam. In connection with the specifics of the problem being solved, optical dust meters are “roughened” and with their help it is impossible to solve the problem of detecting atomized finely dispersed organic powders and aerosols containing pathogenic microorganisms.

 Operational remote monitoring of the current state of the air at a variety of control points is carried out in well-known fire alarm systems, see for example [8], [9]. These systems contain an extensive network of sensors that respond to changes in the parameters of the air at control points due to air pollution from combustion products. In most cases, fire alarm systems are equipped with sensitive optical sensors that respond to smoke, see for example [10], [11], [12].

 In the best systems, especially sensitive sensors are used, for example, similar ones [13], operating both on the principle of recording scattered radiation and on the principle of monitoring transmitted light. These sensors are connected through signal transmission channels to a diagnostic center that receives and analyzes signals, as well as generates alarms in case of smoke detection. At its core, fire alarm systems function as systems for the operational diagnosis of air pollution at monitoring points, and through an analysis of changes in the optical parameters of the air, a particular case of pollution, smoke, is diagnosed.

 In a generalized form, the system of operational diagnostics of air pollution, implemented in [9], is the closest to the claimed system in terms of its main function - operational diagnostics of air pollution at controlled points, as well as by the possibility of implementing this function in relation to ventilation ducts of buildings and structures, adopted as a prototype.

 The system, adopted as a prototype, contains means for exciting signals characterizing the state of the air at the control points. In the example considered in [9], these tools are made on the basis of optical smoke sensors, that is, diagnostics of air pollution by combustion products is carried out. These sensors are located in certain controlled points of a building or structure and are connected to the diagnostic center by electric communication lines. On these lines in accordance with a specific survey program, the sensors are periodically initialized and the signals generated by them are received. When smoke appears at any of the monitored points, the corresponding sensor, in response to a request, generates a signal different from the “normal” one, which is perceived by the data processing center as an “alarm” signal. The information processing center identifies the "alarm point" and generates a corresponding message for the operating personnel and / or a command to automatically activate the fire fighting devices at this point.

 Since the sensors of the system react to changes in the transparency of air at a controlled point, then, to a certain extent, the prototype system can solve the problems of detecting atomized finely dispersed organic powders and aerosols containing pathogenic microorganisms, namely, to the extent that this atomization is accompanied by deterioration transparency of air. In this capacity and to this extent, the prototype system can perform the functions of operational diagnostics of biological air pollution in the ventilation ducts of buildings and structures, however, the real effect of its application to solve practical problems arising from the threat of bioterrorism will be small.

 The task to be solved by the claimed invention is aimed at providing the possibility of real-time diagnostics of biological air pollution with respect to many points in the ventilation ducts of buildings and structures under the threat of bioterrorism, i.e. under the conditions of possible spraying and dispersion by attackers of finely dispersed organic powders and aerosols containing pathogenic microorganisms.

 The essence of the claimed invention lies in the fact that in the system for the operational diagnosis of biological air pollution in the ventilation ducts of buildings and structures, containing means associated with the diagnostic center for generating signals characterizing the state of the air at the control points, these means are made in the form of optical fibers introduced by their chipped or polished ends to the ventilation ducts at the control points.

 Moreover, the opposite ends of these optical fibers are connected through the beam splitters to the input and output optical channels of the diagnostic center, respectively, intended for the input of monochromatic laser radiation, which is part of the diagnostic center, into the optical fibers to excite light scattering and fluorescence signals at the control points if they appear in them dispersed dispersed organic substances and transportation in the opposite direction of the optical fibers received by said ends n excited scattering and fluorescence signals for transmission in their respective photodetectors belonging to the diagnostic center, provided with a spectrally selective optical filters with frequency bands corresponding to frequency bands excited fluorescence and scattering signals.

 In this case, the outputs of the photodetectors are electrically connected to a decision unit that generates, on the basis of the amplitude estimate of the received excited scattering signals and the integrated estimate of the received excited fluorescence signals in the fluorescence band, diagnostic signals for "detecting" or "not detecting" biological air pollution at each control point.

 The invention and the possibility of its implementation are illustrated by the structural diagram of the system shown in the drawing.

The inventive system in this example implementation contains a system of controlled ventilation channels 1 of a building or structure, in which N control points 2 (2 ₁ , 2 ₂ , ..., 2 _N ) are selected as control points. (Here and below, the term "point" is used not in the geometric sense, but in the sense of "place", "local zone").

The system also contains a diagnostic center 3, with which N means are connected for exciting signals characterizing the state of the air at the control points 2 (2 ₁ , 2 ₂ , ..., 2 _N ). The composition of the diagnostic center 3 includes transmitting 4 and receiving 5 blocks.

Means for exciting signals characterizing the state of the air at the control points 2 (2 ₁ , 2 ₂ , ..., 2 _N ) are made in the form of optical fibers 6 (6 ₁ , 6 ₂ , ..., 6 _N ), introduced by the chipped or polished ends into the ventilation ducts 1 at the control points 2 (2 ₁ , 2 ₂ , ..., 2 _N ).

The opposite ends of each of the optical fibers 6 are connected through the respective beam splitters 7 (7 ₁ , 7 ₂ , ..., 7 _N ) with input 8 (8 ₁ , 8 ₂ , ..., 8 _N ) and output 9 (9 ₁ , 9 ₂ , ..., 9 _N ) optical channels. Introductory optical channels 8 are intended for introducing monochromatic radiation from the transmitting unit 4 into optical fibers 6 for exciting light scattering and fluorescence signals at the control points 2 of the ventilation channels 1 in the case of dispersed organic substances - powders or aerosols containing pathogenic microorganisms that appear in them danger to people. The output optical channels 9 are intended for transportation in the opposite direction of the optical fibers 6 of the indicated ends indicated by the excited scattering and fluorescence signals for transmission to the receiving unit 5.

The input optical channels 8 (8 ₁ , 8 ₂ , ..., 8 _N ) are connected to the N optical outputs of the transmitting unit 4, formed by the N outputs of its optical switch 10.

The output optical channels 9 (9 ₁ , 9 ₂ , ..., 9 _N ) are connected to the N optical inputs of the receiving unit 5 formed by the N inputs of its optical switch 11.

In the transmitting unit 4, the input of the optical switch 10 is connected optically to a source of exciting optical radiation - a nitrogen laser 12, which generates UV radiation pulses at a wavelength λ _in = 337 nm with a radiation frequency determined by the frequency of the output signal connected to the laser 12 of the master oscillator 13.

 In the receiving unit 5, the output of the optical switch 11 is connected to the inputs of the photodetectors 14 and 15, equipped with input optical spectrally selective filters with frequency bands corresponding to the frequency bands of the received excited scattering signals (for example, in the photodetector 14) and fluorescence (for example, in the photodetector 15) . The outputs of the photodetectors 14, 15 are connected electrically to the decision unit 16 (processor), which generates, based on the amplitude estimate of the excited scattering signals received by the photodetector 14 and an integrated assessment of the excited fluorescence signals in the fluorescence band of the photodetector 15, diagnostic output signals, including signals signaling about the detection of "or" non-detection "of biological air pollution at each of the control points 2. The decision block 16 is connected to the computer 17, which in turn is connected to the channels and transmitting control (synchronizing) signals with a master oscillator 13 and optical switches 10 and 11, and information transfer channels with external devices, systems or services.

 The inventive system is implemented on the basis of the existing component base and means of fiber-optic equipment and technology used in modern fiber-optic information transmission systems.

 The work of the inventive system for the operational diagnosis of biological air pollution in the ventilation ducts is as follows.

At certain successive times, in accordance with a predetermined program installed by computer 17, the laser 12 of the transmitting unit 4 emits short (τ _and = 3 ns) pulses of UV radiation at a wavelength of λ _in = 337 nm. These pulses pass through the channels of the optical switch 10, which are closed for these moments of time, then pass through the input optical channels 8 connected with them, pass through the beam splitters 7, and enter the optical fibers 6. Passing through the optical fiber 6, the radiation pulses exit from the chip or polished fiber end, probing the air at the control point.

In the case of biological contamination, i.e. in the presence of organic impurities in the air (for example, anthrax spores), fluorescence emission in the longer wavelength range of the spectrum λ _f = 360-460 nm is excited at the control point. In the most dangerous cases, at a high concentration of impurities, sufficiently strong light scattering signals are also excited in the spectral region λ _at = 337 nm. Excited light scattering and fluorescence signals are received at the cleaved or polished ends of the same optical fibers 6 and transported to the receiving unit 5, passing through the corresponding beam splitters 7, output optical channels 9 and closed channels of the optical switch 11.

 From the output of the optical switch 11, the excited light scattering and fluorescence signals from different control points 2 are sequentially delivered to the inputs of photodetectors 14 and 15 in time. Here, the signals are selected by input optical spectrally selective filters, the frequency bands of which correspond to the frequency bands of the received excited scattering signals (in photodetector 14) and fluorescence (in the photodetector 15). Photodetectors 14, 15 convert the received excited light signals from each control point 2 into electrical signals. These electrical signals are fed to the corresponding inputs of the decision block 16.

 The decision unit 16 performs an amplitude estimation of the excited scattering signals received by the photodetector 14 and an integrated assessment of the excited fluorescence signals received by the photodetector 15 in the fluorescence band. Integral assessment of excited fluorescence signals in the best way allows you to diagnose the presence of biological contamination of unknown origin, since the fluorescence spectra of organic substances in the ventilation ducts are blurred and wide bands. The amplitude estimate of the excited scattering signals in the best way allows you to diagnose the presence of a large amount of atomized substance.

 The joint use of both estimates increases the efficiency of diagnostics, allows for a qualitative gradation of pollution according to the degree of danger (the highest danger when both factors coincide). Quantitative gradation is carried out on the basis of comparison with certain threshold values. Based on the estimates of the excited signals for each control point 2, the decisive unit 16 generates output diagnostic signals for "detecting" or "not detecting" biological air pollution of one degree or another of danger (safety). These signals are presented in the form of digital codes generated in accordance with the accepted procedure for bypassing (scanning) control points 2. From the output of the decision block 16, the diagnostic signals are sent to the computer 17.

 The computer 17 synchronizes the operation of the master oscillator 13 and the optical switches 10 and 11, scans and multiplexes the optical channels, identifies and systematizes the diagnostic results by time and control points, and stores information. In addition, the computer 17 communicates, if necessary, with external devices, systems or services, for example, through a modem with rescue services, civil defense, warning equipment, and via communication lines laid inside the building with executive mechanisms that control the position corresponding valves in the ventilation ducts. For example, when diagnosing a high degree of biological pollution at any of the monitoring points 2, computer 17 transmits alarms to the relevant public warning services about the threat of infection, generates control signals to turn on protective equipment that provides localization of the pollution source in controlled ventilation ducts.

 Thus, the claimed system implements multi-channel express control of air quality in the ventilation ducts of buildings and structures in order to identify sprayed finely dispersed organic powders and aerosols of unknown origin that could be dangerous to people.

 The above shows that the claimed invention is feasible, industrially applicable and solves the problem - it provides the possibility of an operational multi-point (multi-channel) diagnosis of biological air pollution in the ventilation ducts of buildings and structures under the threat of bioterrorism, i.e. under the conditions of possible spraying and dispersion by attackers of finely dispersed organic powders and aerosols containing pathogenic microorganisms.

Sources of information
1. RU 2091672 C1, F 24 F 7/06, publ. 09/27/1997.

 2. SU 1641083 A1, G 01 N 21/39, publ. 04/15/1994.

 3. SU 1818958 A1, G 01 N 21/64, publ. 11/10/1998.

 4. RU 1795737 C, G 01 N 21/61, 21/39, publ. 02/27/1995.

 5. RU 2068557 C1, G 01 N 21 // 39, publ. 10/27/1996.

 6. RU 2123682 C1, G 01 N 21/76, 33/48, publ. 12/20/1998.

 7. RU 2095792 C1, G 01 N 21/85, publ. 11/10/1995.

 8. RU 2024064 C1, G 08 B 17/10, publ. 11/30/1994.

 9. RU 2032225 C1, G 08 B 17/10, publ. 03/27/1995.

 10. RU 2125739 C1, G 08 B 17/10, publ. 01/27/1999.

 11. RU 2168767 C1, G 08 B 17/10, publ. 06/10/2001.

 12. RU 2037883 C1, G 08 B 17/10, publ. 06/19/1995.

 13. RU 2173887 C1, G 08 B 17/10, publ. 09/20/2001.

Claims (1)

A system for the operational diagnosis of biological air pollution in the ventilation ducts of buildings and structures, containing means associated with the diagnostic center for generating signals characterizing the state of the air at the control points, characterized in that the means for exciting signals characterizing the state of the air at the control points are made in the form of optical fibers introduced by their chipped or polished ends into the ventilation ducts at the control points, the opposite ends of these optical their fibers are connected through beam splitters to the input and output optical channels of the diagnostic center, intended, respectively, for the input of monochromatic laser radiation, which is part of the diagnostic center, into optical fibers to excite light signals of scattering and fluorescence at the control points in the case of dispersed dispersed particles organic substances and transportation in the opposite direction of the optical fibers of the indicated ends of the excited scattering and fluorescence signals escences for transferring them to the corresponding photodetectors included in the diagnostic center, equipped with optical spectrally selective filters with frequency bands corresponding to the frequency bands of the excited scattering and fluorescence signals, while the outputs of the photodetectors are electrically connected to a decision unit that generates based on the amplitude estimate of the received excited scattering signals and integrated estimation of the received excited fluorescence signals in the fluorescence band diagnostic systems Nala "detection" or "non-detection" biological pollution in each of the control points.