Method and apparatus for detecting and locating explosives, biological, and chemical substances in ducts and structures using tracers

• US 20060248941A1
• Filed: 10/06/2004
• Published: 11/09/2006
• Est. Priority Date: 10/06/2003
• Status: Active Grant

• Current Assignee: Kurion Inc. (Veolia Environnement SA)
• Original Assignee: Vista Engineering Technologies LLC (Veolia Environnement SA)
• Inventors: Maresca, Joseph W. Jr., Bratton, Wesley L.
• Granted Patent: US 7,331,248 B2
• Time in Patent Office: Days
• US Class Current: 73/23.200
• CPC Class Codes: G01M 3/22 for pipes, cables or tubes; for pipe joints or seals; for valves; for welds; for containers, e.g. radiators
• CPC Class Codes: G01M 3/30 using progressive displacement of one fluid by another
• CPC Class Codes: G01N 1/26 with provision for intake from several spaces
• CPC Class Codes: G01N 2001/022 sampling for security purposes, e.g. contraband, warfare agents
• CPC Class Codes: G01N 35/085 Flow Injection Analysis
• CPC Class Codes: Y10T 436/117497 with a continuously flowing sample or carrier stream
• CPC Class Codes: Y10T 436/13 Tracers or tags

Abstract

A method and an apparatus for detecting, locating, and quantifying explosive materials and devices, and naturally occurring and man-made dangerous or hazardous biological and chemical materials and devices in ducts or piping systems, or other fluid flow systems in buildings such as residential, office, industrial, and power plants, transportation systems such as ships, airplanes, subways, and trains, and various types of infrastructure such as dams, tunnels, or bridges, and in the rooms, compartments, enclosures, containers, or difficult to access areas in these buildings, transportation systems, and structures. The preferred embodiment of this detection and location method uses a conservative tracer and one or more interactive tracers that are injected into the duct or area to be searched at one location and then monitored at the same or another location in the duct or area. Alternative embodiments, which are quicker and just as accurate for detection and location, require only the use of interactive tracers. Detection, location, and quantification are accomplished by analysis of the characteristic features of measured curves of tracer concentration. Various types of interactive tracers may be used, including partitioning and reactive tracer gaseous tracers.

Claims

1. A method for characterizing a contaminant in a structure, comprising the steps of:

(a) injecting at a first location an interactive tracer into or onto a region where the contaminant may be located;

(b) extracting at a second location the tracer used to interrogate the contaminant region, wherein the second location may be collocated with the first location;

(d) measuring the concentration of the extracted tracer at one or more periods in time; and

(e) characterizing the contaminant from the concentration of the tracer.

2. The method of claim 1 wherein the characterizing includes locating a specific contaminant of interest in the structure.

3. The method of claim 1 wherein the characterizing includes quantifying the amount of a specific contaminant in the structure.

4. The method of claim 1 wherein a known volume of tracer is injected into the structure.

5. The method of claim 1, further comprising the step of advecting the injected tracer throughout the region containing the contaminant.

6. The method of claim 5 where the injected tracer is advected at an approximately known flow rate throughout the region containing the contaminant.

7. The method of claim 6 where the injected tracer is advected throughout the region containing the contaminant where the geometry of the structure is approximately known.

8. The method of claim 1 wherein a plurality of tracers are injected.

9. The method of claim 1 wherein a conservative tracer is injected with said interactive tracer.

10. The method of claim 1 wherein a plurality of tracers are used and at least one of the tracers is a conservative tracer.

11. The method of claim 1 wherein the interactive tracer is a partitioning tracer.

12. The method of claim 1 wherein the interactive tracer is a reactive tracer.

13. The method of claim 1 wherein the first location and the second location are in communication with the structure.

14. The method of claim 1 wherein the first location and the second location are not in direct communication with the structure.

15. The method of claim 1 wherein the tracer is extracted with an extraction system that includes a pump system that is used to enhance the collection of tracer samples from the structure.

16. The method of claim 1 wherein the tracer is injected with an injection system that includes a pump system used to enhance the distribution of tracer in the structure being interrogated.

17. The method of claim 1 wherein the interactive tracer is injected throughout the entire structure and is allowed sufficient time for the tracer and the contaminant to interact before extraction of the tracer is initiated.

18. The method of claim 1 wherein the tracers are removed from the structure by introducing a fluid into the system that does not interact with the tracer or contaminant and replaces the tracer in the structure.

19. The method of claim 1 where the concentration is measured as a function of time.

20. The method of claim 1 where detection of the presence of a contaminant is determined from the amplitude, shape, or time of arrival of the concentration curve of at least one interactive tracer.

22. The method of claim 6 wherein the location of the contaminant in the structure can be determined from the time of arrival of the tracer emitted from the contaminant and the speed of the advection fluid.

23. The method of claim 6 wherein the location of the contaminant in the structure can be determined from the ratio of the mean time of arrival of the tracer before and after the tracer was removed from the structure and the total distance travel of the tracer between the first location and second location.

21. A method for characterizing a contaminant in a fluid flow system, comprising the steps of:

(a) injecting a conservative tracer and an interactive tracer into the flow system at a first location;

(b) advecting the tracers along the flow system with a fluid that does not interact with the contaminant;

(c) extracting the tracers at a second location in the flow system;

(d) measuring the concentration of the extracted tracers over a period of time; and

(e) characterizing the contaminant using the measured concentrations of the conservative and interactive tracers.

24. A method for determining the location of a contaminant in a flow system, comprising the steps of:

(a) injecting a conservative tracer and a partitioning tracer into the flow system at a first location;

(b) advecting the tracers along the flow system at a first speed to create an advection flow field;

(c) extracting the tracers at a second location in the flow system;

(d) introducing a perturbation to the advection flow field at a perturbation time by changing and then re-establishing the advection flow at a second advection speed, which may be different than the first advection speed, creating a unique change in the concentration of the partition tracer;

(e) extracting the partitioning tracer as a function of time relative to the perturbation time;

(f) measuring the concentration of the partitioning tracer as a function of the time; and

(g) determining the location of contamination from the time of arrival of the partitioning tracer relative to the perturbation time and the advection flow speed.

25. The method of claim 24 wherein detection of the presence of a contaminant is determined from the presence of the interactive tracer that is being emitted from the contaminant after the tracers originally injected into the structure have been removed.

26. The method of claim 24 wherein the distance from the contaminant to the extraction point is determined from the time of arrival of the partitioning tracer after said advection flow field has been re-established.

27. The method of claim 26 wherein the mean time of arrival is determined from the first arrival of the tracer at the extraction point.

28. The method of claim 26 wherein the mean time of arrival is determined from the leading edge of the measured concentration curve at the extraction point.

29. A method for characterizing a contaminant in a fluid flow system, comprising the steps of:

(a) injecting a partitioning tracer into the flow system containing the contaminant;

(b) allowing sufficient time for the partitioning tracer to interact with and partition into the contaminant;

(c) removing the partitioning tracer from the system;

(d) establishing a flow field at one location in the structure with a fluid that does not interact with the contaminant to advect the partitioning tracer being emitted from the contaminant to a second location;

(e) extracting the partitioning tracer at a second location in the flow structure;

(f) measuring the concentration of the extracted tracers over a period of time; and

(g) characterizing the contaminant from the concentration of the partitioning tracer.

30. An apparatus for characterizing a contaminant in a structure, comprising:

(a) a tracer injection system for injecting known amounts of conservative and interactive tracers into the flow system;

(b) an advection driving system for moving the tracers along the flow system;

(c) a tracer extraction system for removing the tracers from the structure;

(d) a measurement system for determining the concentration of the tracers extracted from the structure; and

(e) a processor for analyzing the concentration measurements.

31. The apparatus of claim 30, wherein the injection system includes a container with a valve holding tracers at pressure, whereby the tracers can be injected into the flow system by depressurizing the container by opening the valve on the container.

32. A method for determining the quantity of a contaminant in a structure comprising the method of 47, wherein the quantity of extracted tracer, which is related to the quantity of contaminant, is related to the concentration of the conservative tracer.

33. The method of claim 32 for determining the quantity of a contaminant in a structure that is a fluid flow system, further comprising the steps of:

(a) using conservative and partitioning tracers with known partitioning coefficients;

(b) measuring of the concentration of said tracers as a function of time;

(c) computing the mean arrival time of the conservative and partitioning tracers; and

(d) determining the quantity of contamination from said mean arrival times, said partitioning coefficients, and a factor accounting for the geometry of the structure.

34. The method of claim 33 in which the volume of the contaminant is computed using the formula, S_DPipe=α

(<

t_p>

/<

t_c22 )−

1)/(K_i+(<

t_p>

/<

t_c>

)−

1), where α

is a constant that accounts for the fact that the contaminant layer is on the bottom of the fluid flow system, <

t_p>

is the mean time of travel of the partitioning tracer, <

t_c>

is the mean time of travel of the conservative or non-partitioning tracer, S_D is the average contamination saturation (the fraction of the volume occupied by contamination in the total swept volume of the pipeline), and K_i is the partitioning coefficient of said partitioning tracer.