Harmonic wireless transponder sensor and method

• US 20060044178A1
• Filed: 09/02/2004
• Published: 03/02/2006
• Est. Priority Date: 09/02/2004
• Status: Active Grant

• Current Assignee: The Dow Chemical Company (Dow, Inc.), Michigan State University
• Original Assignee: Michigan State University
• Inventors: Miller, Theodore E. Jr., Warren, Malcolm W. II, Charvat, Gregory L., Kempel, Leo C., Liening, Eugene L.
• Granted Patent: US 7,145,453 B2
• Time in Patent Office: Days
• US Class Current: 342/42
• CPC Class Codes: G06K 19/07749 the record carrier being capable of non-contact communication, e.g. constructional details of the antenna of a non-contact smart card
• CPC Class Codes: H04Q 9/00 Arrangements in telecontrol or telemetry systems for selectively calling a substation from a main station, in which substation desired apparatus is selected for applying a control signal thereto or for obtaining measured values therefrom

Abstract

A method for detecting a latent environmental effect (such as a corrosive environment under insulation) or a latent structural change (such as a crack in a concealed structural member) at a known remote concealed location. The method of the instant invention includes three steps. The first step is to use a harmonic electromagnetic transponder at the known remote concealed location of the latent environmental effect or the latent structural change, the harmonic electromagnetic transponder having a reactive portion which reacts to the latent environmental effect or latent structural change to modify the harmonic emission of the transponder. The second step is to remotely interrogate the transponder by directing electromagnetic radiation at the transponder. The third step is to use the harmonic emission of the transponder to remotely determine the latent environmental effect or the latent structural change.

Claims

1. A method for detecting a latent environmental effect or a latent structural change at a known remote concealed location, comprising the steps of:

(a) using a harmonic electromagnetic transponder at the known remote concealed location of the latent environmental effect or the latent structural change, the harmonic electromagnetic transponder having a reactive portion which reacts to the latent environmental effect or latent structural change to modify the harmonic emission of the transponder;

(b) remotely interrogating the transponder by directing electromagnetic radiation at the transponder; and

(c) using the harmonic emission of the transponder to remotely determine the latent environmental effect or latent structural change.

2. The method of claim 1, wherein the harmonic electromagnetic transponder is a passive harmonic electromagnetic transponder.

3. The method of claim 1, wherein the harmonic emission of the transponder is digitally coded so that the transponder can be uniquely identified.

4. The method of claim 3, wherein the harmonic electromagnetic transponder is an active harmonic electromagnetic transponder.

5. The method of claim 1, wherein the latent environmental effect is a condition that may lead to inadvertent latent corrosion of a metal structure.

6. The method of claim 5, wherein the metal structure is selected from the group consisting of a metal pipe, a metal vessel and a metal structural member.

7. The method of claim 6, wherein the metal structure is selected from the group consisting of an insulated steel pipe, an insulated steel vessel and an insulated steel structural member.

8. The method of claim 7, wherein the reactive portion of the transponder is an electrical conductor that corrodes when it is exposed to the condition that may lead to the inadvertent latent corrosion of the tank.

9. The method of claim 1, wherein the reactive portion of the transponder is a manually re-settable switch that opens or closes in response to an environmental effect or to a structural change.

10. The method of claim 1, wherein the reactive portion of the transponder is an automatically re-setting switch that opens and closes in response to an environmental effect or to a structural change.

11. The method of claim 1, wherein the reactive portion of the transponder is a non re-settable element which responds to an environmental effect or to a structural change.

12. The method of claim 1, wherein the reactive portion of the transponder is a thermistor.

13. The method of claim 1, wherein the reactive portion of the transponder is a humidity sensor whose resistance is a function of the humidity of the sensor.

14. The method of claim 1, wherein the reactive portion of the transponder is a humidity sensor whose capacitance is a function of the humidity of the sensor.

15. The method of claim 1, wherein the reactive portion of the transponder is a switch that opens or closes in the event of a structural change.

16. A method for detecting a latent environmental effect or a latent structural change at a known remote concealed location, comprising the steps of:

(a) directing electromagnetic radiation to the known remote concealed location;

(b) resonating the electromagnetic radiation at the known remote concealed location;

(c) converting the resonated electromagnetic radiation to a harmonic thereof at the known remote concealed location;

(c) transmitting the harmonic electromagnetic radiation from the known remote concealed location; and

(d) using the transmitted harmonic electromagnetic radiation to remotely determine the latent environmental effect or the latent structural change by measuring the relative strength of the transmitted harmonic electromagnetic radiation from the known remote concealed location.