US 3,942,357 A · Inspection apparatus

Abstract

An apparatus for checking the contents of closed containers, such as baggage, for the presence of substances, such as explosives and drugs, which are capable of emitting characteristic vapours. The baggage is located in a compartment having means to promote the diffusion of the vapours out of the baggage and into the compartment. Such means can be by vacuum pumping, by vibration of the atmosphere within the compartment or a combination of both. The vapours diffusing into the compartment are drawn at substantially constant flow rate into a detector assembly sensitive to the presence of the vapours. Initially the concentration of vapours in the atmosphere evacuated from the compartment is low and a major proportion of this evacuated flow by-passes the detector assembly. As the pressure in the compartment is reduced there is an increase in the concentration of the vapours in the atmosphere and at a lower pressure limit all the exhaust from the compartment passes into the detector.

Claims10

Dependent claims

Apparatus for checking the contents of closed containers for the presence of substances which are capable of emitting vapours comprising a compartment to receive the containers, means to promote the rapid diffusion of vapours out of the container into the compartment, a detector assembly sensitive to the presence of the vapours and connected to said compartment by a flow path so as to receive at least a proportion of the vapours diffusing into the compartment, means selectively permeable to the vapours and located in the flow path to the detector assembly, and means for maintaining the selectively permeable means at a constant temperature.

Apparatus for rapidly checking the contents of closed containers for the presence of substance capable of emitting vapours, comprising:

a compartment for receiving the containers and having an exhaust port;
a vacuum pump;
first relatively high flow rate passage means connecting said vacuum pump to said compartment exhaust port for rapid initial evacuation of said compartment to a lower limit of pressure whereat vapours seeping into the compartment from substances in a said container achieve a maximum concentration in the compartment;
second relatively low flow rate passage means in parallel with said first passage means and connecting said vacuum pump to said compartment exhaust port, said second passage means including a reduced cross-section portion receiving vapors from said compartment exhaust port, and a detector feed conduit coupled thereto;
means for maintaining a preselected flow rate through said reduced cross-section portion and including valve means interposed in said first passage means and (1) actuable to an open condition for maximizing the rate of evacuation of said compartment by said vacuum pump until said lower limit of pressure is reached, and (2) thereafter actuable to substantially close said first passage means for causing substantially all the exhaust flow from said compartment through said reduced cross-section portion;
detector means connected to said detector feed conduit for detecting the presence of vapours of interest passing through detector feed conduit;
whereby initial pumping is primarily through said first passage means and rapidly draws vapours from said containers in said compartment to maximize the amount of such vapours in the compartment exhaust, and subsequent pumped flow of compartment exhaust is at least primarily through said second passage means for detection of vapours of interest.

4 more elements

Dependencies are inferred from the claim text.

Inspection apparatus

Life of this patent

Inspection apparatus

Life of this patent

Abstract

Claims10