Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B64—AIRCRAFT; AVIATION; COSMONAUTICS
  • B64D—EQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLIGHT SUITS; PARACHUTES; ARRANGEMENT OR MOUNTING OF POWER PLANTS OR PROPULSION TRANSMISSIONS IN AIRCRAFT
  • B64D45/00—Aircraft indicators or protectors not otherwise provided for
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
  • G01N15/06—Investigating concentration of particle suspensions
  • G01N15/0606—Investigating concentration of particle suspensions by collecting particles on a support
  • G01N15/0637—Moving support
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
  • G01N15/06—Investigating concentration of particle suspensions
  • G01N15/0656—Investigating concentration of particle suspensions using electric, e.g. electrostatic methods or magnetic methods
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
  • G01R29/00—Arrangements for measuring or indicating electric quantities not covered by groups G01R19/00 - G01R27/00
  • G01R29/12—Measuring electrostatic fields or voltage-potential
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01W—METEOROLOGY
  • G01W1/00—Meteorology
  • G01W1/08—Adaptations of balloons, missiles, or aircraft for meteorological purposes; Radiosondes

Definitions

• the invention relates to apparatus and methods for aerosol detection, and particularly to the detection of solid particles, such as particles of ash, dust, ice, snow, rain or pollution, in the atmosphere.
• Airborne particulates are typically detected and analysed over large regions of the atmosphere by means of complex particle-sensing instrumentation mounted on aircraft.
• an aerosol spectrometer may be mounted on an aircraft, and the aircraft may then be flown through the atmosphere with air being drawn through the spectrometer by a vacuum pump.
• Certain commercially available aerosol spectrometers such as the Model 1.129 Sky-OPC manufactured by Grimm Aerosoltechnik GmbH & Co KG, are specifically designed for atmospheric research, and allow data relating to particle size and particle density to be recorded on an integrated data storage card as a function of time and/or the position of an aircraft on which the spectrometer is mounted.
• Such devices are complex and expensive. They require significant time and effort to be fitted to aircraft.
• Particle analysis in such devices is typically carried out by means of optical scattering measurements in which light from a laser or LED is scattered by the particles , and the presence, size and density of the particles is inferred from measurements of scattered light.
• optical scattering measurements in which light from a laser or LED is scattered by the particles , and the presence, size and density of the particles is inferred from measurements of scattered light.
• dedicated research aircraft are generally required because of aircraft safety certification regulations. This means that commercial aircraft which fly through a given region of the atmosphere, and which could potentially gather data on airborne particulates as a function of position in the region, are not able to be exploited to gather such data.
• a first aspect of the present invention provides aerosol detection apparatus comprising an aircraft having a dielectric member comprised in the body thereof such that a surface of the dielectric member forms part of the exterior surface of the aircraft, and detection means located in the interior of the aircraft and arranged to detect an electric field resulting from polarisation of the dielectric member.
• the polarisation of the dielectric member may take place by one or more of a number of different mechanisms . Aerosol particles which are already charged can transfer their charge to the surface of the dielectric member forming part of the exterior of the aircraft, as the aircraft is flown through the aerosol. Uncharged aerosol particles may also cause charging of that surface by a frictional mechanism.
• the dielectric member may be a window of the aircraft, in which case any general purpose aircraft may be used. In other words no special dielectric member is required to be retro-fitted to an aircraft, or used in the construction of a new aircraft, in order to implement the invention.
• a window of BAe ' 146' aircraft comprises an external layer of acrylic, which serves well as a dielectric member.
• the detection means may be a static monitor mounted within the aircraft.
• An electro-static voltmeter such as electro-mechanical field mill instrument, may be used.
• a suitable electro-mechanical field mill is the JCI 140 static monitor manufactured by Chilworth Technology Ltd of Southampton, U.K.
• the apparatus further comprises a data acquisition system arranged to record the output of the static monitor, or the rate of change of the output of the static monitor, as a function of position of the aircraft.
• the electric field resulting from accumulated charge on the surface of the dielectric as the aircraft is flown through airspace containing particles indicates the presence of an aerosol. Recording the output of the static monitor (or its rate of change) as a function of position allows the presence of aerosol particles to be mapped.
• Aircraft position may be obtained in a number of ways. For example when flying at constant velocity, total elapsed flight time is a measure of aircraft position.
• the apparatus may instead comprise processing means arranged to convert the output of the static monitor, or the rate of change of the output of the static monitor, directly (i.e. in real time) to a values of aerosol particle density on the basis of an assumed functional form for aerosol particle as a function of the output of the static monitor, or as the case may be the rate of change of the output of the static monitor.
• the apparatus may further comprise a data acquisition system arranged to record values of aerosol particle density output by the processing means as a function of the position of the aircraft, so that the data acquisition system stores a mapping of aerosol particle density.
• the apparatus further comprises a global positioning system (GPS) arranged to output positional information for the aircraft to the data acquisition system for the reasons given above.
• GPS global positioning system
• a second aspect of the invention provides a method of detecting particles in an aerosol comprising the step of causing an apparatus of the invention to pass through a region of the atmosphere containing the particles.
• Figure 1 shows a portion of a first example apparatus of the invention
• Figure 2 shows a dielectric member of the Figure 1 portion in more detail
• Figure 3 shows a portion of a second example apparatus of the invention
• Figure 4 shows traces of aerosol particle density obtained using a nephelometer and of the output of a static monitor comprised in apparatus of the invention
• Figure 5 shows traces of aerosol particle density obtained using an optical spectrometer and of the output of a static monitor comprised in apparatus of the invention.
• Figure 6 shows traces of aerosol mass density obtained using dedicated instrumentation and of the rate of change of the output of a static monitor comprised in apparatus of the invention.
• Figure 1 shows a portion of a first example apparatus of the invention, the apparatus comprising a BAe ' 146' aircraft having metallic fuselage 12 having a window 10, an outer surface of which forms part of the exterior of the aircraft.
• An instrument package 20 is mounted on the interior of the aircraft, the instrument package 20 comprising an electro-mechanical field mill sensor 16 (e.g. model JCI 140 static monitor manufactured by Chilworth Technology Ltd, Southampton , U.K.) .
• the output of the sensor 16 is coupled to a data acquisition system 18 which is arranged to record the output of the sensor 18 at regular intervals, each value of the output of the sensor 16 being recorded together with the position of the aircraft at the time the output is recorded.
• a global positioning system (GPS) unit 22 is arranged to supply positional information relating to the aircraft to the data acquisition system 18.
• a processor 24 coupled to the data acquisition system 18 is arranged to process information stored in the data acquisition system 18.
• the aircraft is flown through a region of the atmosphere containing particles of dust, ash, pollution etc, in other words a region of the atmosphere which is an aerosol.
• Aerosol particles which are charged and which impinge on the outer surface of the window 10 can transfer their charge to the outer surface of the window 10.
• uncharged particles which impinge on the window 10 can cause additional charging of the window 10 by a frictional mechanism.
• Charged and uncharged particles can also give rise to charging of parts of the exterior of the aircraft other than the outer surface of the window 10.
• the window 10 becomes polarised as a result of an electric field generated by one or more of these mechanisms .
• the output of the sensor 16 may be a more complex function of particle density.
• the rate of change of the output of the sensor 16 may be a linear or a more complex function of aerosol particle density.
• the functional relationship for a particular type of aerosol may be guessed or found previously from experience using other instruments or measurements.
• the processor 24 thus allows aerosol particle density as a function of position to be found, i.e. aerosol particle density to be mapped.
• Output from the processor 117 corresponds directly to aerosol particle density, which is recorded at each of a series of times by a data acquisition system 118, together with the position of the aircraft as indicated by a GPS 122.
• the data acquisition system 118 therefore stores information mapping aerosol particle density as a function of position.
• trace 220 (referred to vertical axis 221) is the same as trace 200 in Figure 4.
• Figure 5 also shows a trace 230 of the output of a passive cavity aerosol probe (PCASP) , also mounted on the research aircraft, during the same four hour time period during which the trace 220 was recorded.
• PCASP passive cavity aerosol probe
• Track 230 is referred to vertical axis 231) .
• a PCASP is an optical spectrometer for detecting and analysing aerosols .
• Figure 5 shows a close correlation between aerosol particle density, as measured by the PCASP, and the output of the electromechanical field mill sensor mounted within the research aircraft.
• Figure 6 shows a trace 240 of the rate of change of the output of the same electromechanical field mill sensor over a period of 3.5 hours (referred to vertical axis 241) and also a trace 250 of the mass concentration of volcanic ash over the same period as determined by a dedicated particle- density measuring instrument fixed to the research aircraft.
• Figure 6 shows a close correlation between the rate of change of the output of the sensor and the aerosol particle density of the volcanic ash cloud through which the research aircraft was flown.
• the output of the detection means may be monitored (e.g. input to a comparator) so that a warning signal may be generated if the output exceeds a threshold level associated with a level of aerosol particle density likely to damage the aircraft in some way (e.g. engine damage) .
• the warning signal could be used to give a visual and/or audible signal to the pilot of the aircraft.
• the warning signal may be used to automatically control the flight control systems of the aircraft so that the aircraft is steered to a region of airspace with a lower aerosol particle density.

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• Chemical & Material Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• General Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Pathology (AREA)
• Environmental & Geological Engineering (AREA)
• General Health & Medical Sciences (AREA)
• Analytical Chemistry (AREA)
• Immunology (AREA)
• Health & Medical Sciences (AREA)
• Dispersion Chemistry (AREA)
• Biochemistry (AREA)
• Aviation & Aerospace Engineering (AREA)
• Atmospheric Sciences (AREA)
• Biodiversity & Conservation Biology (AREA)
• Ecology (AREA)
• Environmental Sciences (AREA)
• Investigating Or Analysing Materials By Optical Means (AREA)
• Other Investigation Or Analysis Of Materials By Electrical Means (AREA)
• Traffic Control Systems (AREA)

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• 2010
  • 2010-09-27 GB GBGB1016222.0A patent/GB201016222D0/en not_active Ceased
• 2011
  • 2011-09-19 CA CA2812752A patent/CA2812752C/en active Active
  • 2011-09-19 BR BR112013007332-2A patent/BR112013007332B1/pt active IP Right Grant
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