SECURITY SYSTEM FOR UNDERGROUND CONDUIT

• US 20140091809A1
• Filed: 03/26/2012
• Published: 04/03/2014
• Est. Priority Date: 03/25/2011
• Status: Active Grant

• Current Assignee: Ohio University
• Original Assignee: Ohio University
• Inventors: Sargand, Shad M., Mitchell, Gayle F.
• Granted Patent: US 9,389,271 B2
• Time in Patent Office: Days
• US Class Current: 324/539
• CPC Class Codes: G01R 31/11 using pulse reflection methods
• CPC Class Codes: G01R 31/58 Testing of lines, cables or conductors testing of electric windings G01R31/72

Abstract

In a method for detecting disruptions proximate to an underground conduit, at least one signal carrying cable is positioned along a length of the conduit and between the conduit and a ground surface. At least one cable engaging member is connected to spaced apart locations on the at least one signal carrying cable to extend laterally outward of the at least one signal carrying cable. Each of the at least one cable engaging members is configured to transmit a force to the at least one signal carrying cable when impacted by an external force. A monitoring signal is provided to the at least one signal carrying cable, and a reflected monitoring signal is received in response to the supplied monitoring signal. One or more properties of the reflected monitoring signal are compared to one or more corresponding properties of a predicted reflected monitoring signal. An alert is initiated when the one or more properties of the reflected monitoring signal differ from the one or more properties of the predicted reflected monitoring signal by a predetermined amount.

Claims

1. A system for monitoring a protected structure, the system comprising:

at least one signal carrying cable;

a signal generating mechanism in electrical communication with the at least one signal carrying cable and configured to provide a monitoring signal on the at least one signal carrying cable;

a signal measuring mechanism in electrical communication with the at least one signal carrying cable and configured to receive a reflected monitoring signal from the at least one signal carrying cable in response to the monitoring signal, the signal measuring mechanism comparing one or more properties of the reflected monitoring signal with one or more corresponding properties of a predicted reflected monitoring signal, the signal measuring mechanism being further configured to initiate an alert when the one or more properties of the reflected monitoring signal differ from the one or more properties of the predicted reflected monitoring signal by a predetermined amount; and

at least one cable engaging member connected to spaced apart locations on the at least one signal carrying cable, wherein a force applied to one of the plurality of cable engaging members is transmitted to the at least one signal carrying cable to alter the at least one signal carrying cable at the corresponding spaced apart location, thereby altering the reflected monitoring signal, such that the properties of the reflected monitoring signal differ from the properties of the predicted reflected monitoring signal.

2. The system of claim 1, wherein the signal measuring mechanism is further configured to determine the altered location on the at least one signal carrying cable based on the properties of the reflected monitoring signal.

3. The system of claim 1, wherein the plurality of cable engaging members comprise cords.

4. The system of claim 1, wherein the at least one signal carrying cable comprises a plurality of substantially parallel signal carrying cables.

5. The system of claim 4, wherein each of the plurality of cable engaging members is connected with each of the plurality of signal carrying cables.

6. The system of claim 4, wherein the plurality of cable engaging members and the plurality of signal carrying cables form a monitoring grid.

7. The system of claim 1, wherein at least a portion of the plurality of cable engaging members extend substantially parallel to the at least one signal carrying cable.

8. The system of claim 1, wherein at least a portion of the plurality of cable engaging members extend substantially perpendicular to the at least one signal carrying cable.

9. The system of claim 1, wherein the alert comprises at least one of an audible alarm, indicator light, console display, e-mail message, text message, or automated telephone message.

10. The system of claim 1, wherein the at least one signal carrying cable comprises a coaxial cable.

11. The system of claim 1, wherein the at least one signal carrying cable comprises a fiber-optic cable.

12. The system of claim 1, wherein the one or more properties comprise at least one of timing of the reflected monitoring signal and magnitude of the reflected monitoring signal.

13. A method for detecting disruptions proximate to an underground conduit, the method comprising:

positioning at least one signal carrying cable along a length of the conduit and between the conduit and a ground surface;

positioning a plurality of cable engaging members connected to spaced apart locations on the at least one signal carrying cable to extend laterally outward of the at least one signal carrying cable, wherein each of the plurality of cable engaging members is configured to transmit a force to the at least one signal carrying cable when impacted by an external force;

providing a monitoring signal to the at least one signal carrying cable;

receiving a reflected monitoring signal in response to the supplied monitoring signal;

comparing one or more properties of the reflected monitoring signal to one or more corresponding properties of a predicted reflected monitoring signal; and

initiating an alert when the one or more properties of the reflected monitoring signal differ from the one or more properties of the predicted reflected monitoring signal by a predetermined amount.

14. The method of claim 13, further comprising determining a location of a disruption in the at least one signal carrying cable based on a detected difference between the one or more properties of the reflected monitoring signal and the one or more corresponding properties of the predicted reflected monitoring signal.

15. The method of claim 14, wherein the determined location corresponds with one of the spaced apart locations on the at least one signal carrying cable.

16. The method of claim 13, wherein each of the plurality of cable engaging members wherein a force applied to one of the plurality of cable engaging members is transmitted to the at least one signal carrying cable to alter the corresponding location on the at least one signal carrying cable, thereby altering the reflected monitoring signal, such that the properties of the reflected monitoring signal differ from the properties of the predicted reflected monitoring signal

17. The method of claim 13, wherein positioning at least one signal carrying cable along the length of the conduit comprises positioning a plurality of signal carrying cables in a substantially parallel array.

18. The method of claim 17, wherein each of the plurality of cable engaging members extends substantially perpendicular to the plurality of signal of signal carrying cables, thereby forming a monitoring grid.

19. The method of claim 13, further comprising delivering the alert signal to a user by wireless communication.

20. A conduit monitoring system comprising:

an underground conduit;

at least one signal carrying cable positioned outward of the underground conduit extending along a length of the underground conduit;

a signal generating mechanism in electrical communication with the at least one signal carrying cable and configured to provide a monitoring signal on the at least one signal carrying cable;

a signal measuring mechanism in electrical communication with the at least one signal carrying cable and configured to receive a reflected monitoring signal from the at least one signal carrying cable in response to the monitoring signal; and

a plurality of cable engaging members connected to spaced apart locations on the at least one signal carrying cable and extending laterally outward of the at least one signal carrying cable, wherein a force applied to one of the plurality of cable engaging members is transmitted to the at least one signal carrying cable to alter the at least one signal carrying cable at the corresponding spaced apart location, thereby altering the reflected monitoring signal;

wherein the system is configured to generate an alert when a reflected monitoring signal deviates from a predicted monitoring signal.

21. The system of claim 20, wherein the plurality of cable engaging members comprise laterally extending non-conductive cords woven with the at least one signal carrying cable to form a longitudinally extending web.