초록 ▼

A portal trace detection apparatus is provided for detecting minute particles of interest, such as traces of narcotics, explosives and other contraband. The apparatus includes a portal through which a human suspect will pass. A detection apparatus is disposed at least partly in the ceiling of the po

A portal trace detection apparatus is provided for detecting minute particles of interest, such as traces of narcotics, explosives and other contraband. The apparatus includes a portal through which a human suspect will pass. A detection apparatus is disposed at least partly in the ceiling of the portal, and hence above the human subject in the portal. Particles of interest will be entrained in the human thermal plume that exists in the boundary layer of air adjacent the suspect, and will flow upwardly from the suspect to the detection apparatus in the ceiling of the portal. The portal includes a plurality of vertically aligned arrays of air jets. The air jets are fired sequentially from bottom to top to produce short bursts of air sufficient to disturb the clothing of the suspect and to dislodge particles of interest from the clothing. The dislodged particles of interest are entrained in the air in the human thermal plume and are transported upwardly to the detector.

대표청구항 ▼

A portal trace detection apparatus is provided for detecting minute particles of interest, such as traces of narcotics, explosives and other contraband. The apparatus includes a portal through which a human suspect will pass. A detection apparatus is disposed at least partly in the ceiling of the po

A portal trace detection apparatus is provided for detecting minute particles of interest, such as traces of narcotics, explosives and other contraband. The apparatus includes a portal through which a human suspect will pass. A detection apparatus is disposed at least partly in the ceiling of the portal, and hence above the human subject in the portal. Particles of interest will be entrained in the human thermal plume that exists in the boundary layer of air adjacent the suspect, and will flow upwardly from the suspect to the detection apparatus in the ceiling of the portal. The portal includes a plurality of vertically aligned arrays of air jets. The air jets are fired sequentially from bottom to top to produce short bursts of air sufficient to disturb the clothing of the suspect and to dislodge particles of interest from the clothing. The dislodged particles of interest are entrained in the air in the human thermal plume and are transported upwardly to the detector. tter and a second ultrasonic wave receiver, the first phase difference detector and the second phase difference detector may be combined to be a phase difference detector and the first loop connection and the second loop connection may be combined to be a loop connection. 4. An ultrasonic flow rate meter, which measures a flow rate of a fluid flowing through a conduit, comprising: an ultrasonic wave transmitter disposed in the conduit; an ultrasonic wave receiver disposed at a predetermined distance from the ultrasonic wave transmitter; a PLL circuit connected to the ultrasonic wave transmitter and the ultrasonic wave receiver, said PLL circuit being operative iteratively to adjust an output frequency of an oscillator until a detected phase difference becomes zero, whereby a first oscillating frequency is selected; and a measurement controller for obtaining said first oscillating frequency and converting the oscillating frequency to a flow rate; wherein the PLL circuit has a phase difference detector for detecting a phase difference between an ultrasonic wave transmitted from the ultrasonic wave transmitter and an ultrasonic wave received by the ultrasonic wave receiver, an integrating circuit for integrating an output waveform outputted from the phase difference detector, and the oscillator, which is controlled by an output signal outputted from the integrating circuit. 5. An ultrasonic flow rate, which measures a flow rate of a fluid flowing through a conduit, comprising: an ultrasonic wave transmitter disposed in the conduit; a first ultrasonic wave receiver and a second ultrasonic wave receiver disposed at a predetermined distance from the ultrasonic wave transmitter in the opposite direction respectively; a PLL circuit connected to the ultrasonic wave transmitter; a switching device connected to the PLL circuit; and a measurement controller for obtaining an oscillating frequency of an oscillator and converting the oscillating frequency to a flow rate; wherein the switching device alternatively changes connection of the PLL circuit to be connected either to the first ultrasonic wave receiver or to the second ultrasonic wave receiver, and the PLL circuit has a phase differences detector for detecting a phase difference between an ultrasonic wave transmitted from the ultrasonic wave transmitter and an ultrasonic wave received by the first or the second ultrasonic wave receiver respectively, an integrating circuit for integrating an output waveform outputted from the phase difference detector, and the oscillator, which is controlled by an output signal outputted from the integrating circuit. 6. An ultrasonic flow rate meter, which measures a flow rate of a fluid flowing through a conduit, comprising: an ultrasonic wave generator for generating an ultrasonic wave; an ultrasonic wave transmitter disposed in the conduit, the transmitter transmitting an ultrasonic wave generated from the ultrasonic wave generator; an ultrasonic wave receiver disposed at a predetermined distance from the ultrasonic wave transmitter; a phase difference detector for detecting a phase difference between an ultrasonic wave transmitted from the ultrasonic wave transmitter and an ultrasonic wave received by the ultrasonic wave receiver; an integrating circuit for integrating an output waveform outputted from the phase difference detector; an oscillator controlled by an output signal outputted from the integrating circuit, said oscillator having its output frequency adjusted until a detected phase difference becomes zero, whereby a first oscillating frequency is selected; and a measurement controller for obtaining said first oscillating frequency of the oscillator and converting the oscillating frequency to a flow rate. 7. An ultrasonic flow rate meter according to claim 4 comprising two sets of the ultrasonic flow rate meter. 8. An ultrasonic flow rate meter, which measures a flow rate of a fluid flowing through the condui