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Exposive detection screening system

  • US 4,987,767 A
  • Filed: 12/08/1989
  • Issued: 01/29/1991
  • Est. Priority Date: 06/09/1989
  • Status: Expired due to Fees
First Claim
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1. A walk-through explosive detection screening system for the detection of concealed explosives, chemical agents and other controlled substances such as drugs or narcotics by detecting their vapor or particulate emissions, said system comprising:

  • (a) a walk-through sampling chamber means for gathering a sample of the environment surrounding a person or object passing through said sampling chamber means by sweeping the vapor or particulate emissions from said person or object, said sampling chamber means having an entrance and exit portal defined by at least two walls, and a convergent ceiling which opens into an air plenum;

    (b) a pair of inwardly directed and vertically oriented air flow guide means on either side of each of said entrance and exit portals, said air flow guide means directing air towards a center region of said sampling chamber means with a predetermined velocity, the combination of said air flows from said pair of inwardly directed and vertically oriented air flow guide means creating a dynamic high pressure zone in said sampling chamber means;

    (c) means for recirculating air between said pair of inwardly directed and vertically oriented guide means and said air plenum, the recirculating air creating a dynamic low pressure zone in the region of said convergent ceiling, said dynamic high and low pressure zones creating a region within said sampling chamber means that does not allow an appreciable amount of air in or out of said entrance and exit portals;

    (d) a sample collection means to collect a sample volume of air that is swept off the individual or object passing through said sampling chamber means, said sample collection means including means for collecting a volume of air from a sampling port mounted in the plenum and centered in said convergent ceiling;

    (e) means for concentrating said vapor or particulate emissions collected by said sample collection means, said means for concentrating having a first means for adsorption and a second means for desorption of said concentrated vapor or particulates;

    (f) detecting means responsive to said vapor or particulate emissions desorbed from said second means for desorption to generate a first signal and an alarm.

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