Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B64—AIRCRAFT; AVIATION; COSMONAUTICS
  • B64F—GROUND OR AIRCRAFT-CARRIER-DECK INSTALLATIONS SPECIALLY ADAPTED FOR USE IN CONNECTION WITH AIRCRAFT; DESIGNING, MANUFACTURING, ASSEMBLING, CLEANING, MAINTAINING OR REPAIRING AIRCRAFT, NOT OTHERWISE PROVIDED FOR; HANDLING, TRANSPORTING, TESTING OR INSPECTING AIRCRAFT COMPONENTS, NOT OTHERWISE PROVIDED FOR
  • B64F1/00—Ground or aircraft-carrier-deck installations
  • B64F1/36—Other airport installations
  • B64F1/368—Arrangements or installations for routing, distributing or loading baggage
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F42—AMMUNITION; BLASTING
  • F42D—BLASTING
  • F42D5/00—Safety arrangements
  • F42D5/04—Rendering explosive charges harmless, e.g. destroying ammunition; Rendering detonation of explosive charges harmless
  • F42D5/045—Detonation-wave absorbing or damping means

Definitions

• the present invention relates to the field of air cargo screening systems for the detection of the presence of explosive devices therein.
• a bomb which terrorists have used with success is a bomb which has a pressure sensitive trigger device which may require a pressure cycling between normal atmospheric (airport level) pressure and a reduced pressure characteristic of flight at normal altitudes a predetermined number of times, such as one or two, before the bomb is initiated upon an additional drop in pressure indicative of another flight at altitude. It is believed that in at least some cases, the pressure sensitive trigger device does not itself set off the bomb, but rather initiates a timing device set to trigger the bomb before the then current flight is over. Thus, a bomb may be placed in air cargo for a particular destination, to go off in the second or third leg of the trip to the air cargo destination, with the bomb being successfully set off during the desired leg of the trip, independent of intervening flight delays and the like.
• Inspection techniques for the inspection of passengers, carryon baggage, stowed (checked) baggage and other more general forms of air cargo are well known. Such techniques generally include x-raying of baggage, the use of metal detectors for searching passengers themselves, and the use of dogs for
• the apparatus includes a pressure vessel with large blowout ports for venting the same to the atmosphere upon an
• the pressure vessel being a metallic enclosure or at least having a conductive layer, acts as a screen room, isolating the pressure vessel interior from external electromagnetic
• Figure 1 is a perspective schematic view of one embodiment of the invention.
• pressure vessel herein and in the appended claims is meant to mean a vessel having one or more doors thereon, which when closed, form a sealed enclosure capable of withstanding a substantial positive (super-ambient internal pressure) and negative (sub-ambient internal pressure) differential pressures.
• the pressure vessel preferably is a metallic enclosure, and therefore when the door or doors thereof are closed, forms a complete metal enclosure shielding the interior volume thereof from substantially all external electromagnetic radiation.
• the pressure vessel illustrated in Figure 1 is preferably large enough to receive air cargo shipping containers on some
• the pressure vessel 20 has a single door 22 at the front thereof, and some form of floor for receiving a dolly, or conveyor, such as a roller conveyor 24, for receiving air cargo. Also,
• blowout ports 26 are provided across the top of the pressure vessel 20, which ports will blow out to vent the interior of the pressure vessel to ambient pressure upon the buildup of the pressure within the pressure vessel to some pressure well above normal operating pressures, but of course still well below the rupture pressure for the pressure vessel.
• a second door may be disposed conveniently at the other end of the pressure vessel so that the same may be loaded from one end and unloaded from the other end, if desired.
• an air pump or compressor 30 coupled to the pressure vessel 20 though an air line 28 is an air pump or compressor 30 controlled by a controller 32.
• pump or compressor 30 should be capable of producing positive or negative pressures with the respect to ambient pressure, or alternatively might be two devices, one for producing a sub- ambient pressure at its output and the other for producing a super-ambient pressure.
• a single compressor may appropriately be used, with valving to couple line 28 to the low pressure side of compressor 30 or to the high pressure side .of the compressor, and to vent the same to ambient pressure.
• a single compressor may appropriately be used, with valving to couple line 28 to the low pressure side of compressor 30 or to the high pressure side .of the compressor, and to vent the same to ambient pressure.
• compressor could be used in this way to pump up or pump down the pressure within the pressure vessel upon command.
• the controller 32 is preferably some form of automatic programmable controller, such as by way of example, a personal computer with appropriate interface therein so as to be
• the sensors 34 are coupled to a receiver/warning system or monitor 36, which in turn may be coupled to the controller 32 as shown.
• the sensors 34 preferably may be any form of electromagnetic radiation sensors suitable for detecting electromagnetic radiation and noise characteristic of a switch turning on power to a electronic device.
• the triggering device mechanically senses changes in pressure, and upon a preset number of pressure cyclings (typically a small number such as one or two) each indicative of a takeoff and a landing, a trigger mechanism turns on electrical power to a timer for the bomb upon a subsequent drop in pressure indicative of the takeoff for another leg of the journey.
• a switch closure turning on power to an electronic device normally will cause the switch and lead wires through which the current surge passes to emit electromagnetic radiation, normally as a fairly wide band noise pulse, as mechanical switches generally exhibit contact bounce which increases the amplitude and extends the duration of the resulting electromagnetic noise.
• electromagnetic radiation normally as a fairly wide band noise pulse
• mechanical switches generally exhibit contact bounce which increases the amplitude and extends the duration of the resulting electromagnetic noise.
• Suitable sensors may include antennas of various kinds, including simple metallic antennas and ferrite antennas, though preferably a plurality of such sensors are used, perhaps of different kinds and preferably if directional, oriented in different directions to maximize the opportunity for detection of such a switch closure.
• one or more sensors on cables may be disposed on or directly within the air cargo for better sensing capability.
• air cargo packaged within an aluminum shipping container preferably would have such a sensor disposed within the shipping container, as such containers themselves may provide undesired shielding of the radiation given off by such switch closures.
• air cargo which may be or include baggage and even carryon items, would be loaded into the pressure vessel 20, and if moveable electromagnetic sensors are used,
• controller 32 will normally be programmed to first reduce the pressure in pressure vessel 20 to a pressure at least below the pressure the cargo would be expected to encounter in flight. Suitable reduced pressures might be by way of example a pressure corresponding to approximately 5,000 to 10,000 feet or perhaps even higher.
• the controller 32 would allow the pressure in the pressure vessel 20 to return to ambient, either by reversing the connections of compressor 30 or alternatively merely venting line 28 to ambient pressure, with the compressor 30 then pressurizing the chamber to a super- ambient pressure, again adequate to advance a pressure sensitive detonation device in its operating cycle.
• the super-ambient pressure may be in the range of 15 to 20 psia, or more
• the controller 32 will normally be preprogrammed to cycle between these sub-ambient pressures and the super-ambient pressures a
• predetermined number of times typically at least three, or alternatively, at least a number of times equal to or greater than the number of pressure cycles corresponding to the number of takeoffs and landings before the air cargo is to be unloaded at its final destination.
• the sensor monitor 36 may monitor the various radiation sensors within the pressure vessel and upon the detection of a switch closure, will provide an audible alarm, and may provide a signal to the controller 32 to perhaps immediately vent the pressure vessel 20 so that the contents thereof may be immediately removed and moved to a remote or armored location, or alternatively to drive the pressure in the pressure vessel 20 to a level that is calculated to allow the pressure vessel to best withstand the detonation of an explosive charge therein, such as a grossly reduced pressure.
• sensing may be used to cause the controller to pressure cycle the pressure vessel additional times
• pressure vessel described herein is a fabricated steel pressure vessel, it should be noted that the same may be lined with an energy absorbing composite
• the main structure of the vessel itself may be a high strength composite material
• the pressure vessel or at least some layer thereof should be conductive or should at least include a conductive screen to shield the interior from exterior electromagnetic radiation to avoid false sensing of external light switch operation, vehicle starter solenoid operation, etc.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Aviation & Aerospace Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Investigating Or Analyzing Materials Using Thermal Means (AREA)
• Filling Or Discharging Of Gas Storage Vessels (AREA)
• Measuring Fluid Pressure (AREA)

Priority Applications (3)

Applications Claiming Priority (2)

Publications (1)

Family

ID=24741704

Family Applications (1)

Country Status (5)

Cited By (2)

Citations (3)

• 1992
  • 1992-04-09 AU AU17990/92A patent/AU1799092A/en not_active Abandoned
  • 1992-04-09 JP JP4510269A patent/JPH06508921A/ja active Pending
  • 1992-04-09 DE DE4291053T patent/DE4291053T1/de not_active Withdrawn
  • 1992-04-09 WO PCT/US1992/002884 patent/WO1992018960A1/en active Application Filing
• 1993
  • 1993-10-11 GB GB9320924A patent/GB2272065A/en not_active Withdrawn

Patent Citations (3)

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