Magnetomechanical markers for marking stationary assets

• US 9,638,822 B2
• Filed: 04/21/2015
• Issued: 05/02/2017
• Est. Priority Date: 09/22/2010
• Status: Active Grant

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Doany, Ziyad H., Dowdle, Dean M., Hamerly, Michael E., Egbert, William C., Joyce, Jr., Terrence H.
• Primary Examiner(s): Girma, Fekadeslassie
• Application Number:
  US14/691,654
• Publication Number:
  US 20150226872A1
• Time in Patent Office: 742 Days
• CPC Class Codes: G01V 15/00 Tags attached to, or associated with, an object, in order to enable detection of the object record carriers for use with machines having a detectable tag or marker G06K19/00
• CPC Class Codes: G01V 3/081 the magnetic field is produced by the objects or geological structures characterised by the method of magnetic field measurement G01R33/00
• CPC Class Codes: G01V 3/38 Processing data, e.g. for analysis, for interpretation, for correction
• CPC Class Codes: G06K 19/0672 with resonating marks
• CPC Class Codes: G08B 13/2437 Tag layered structure, processes for making layered tags

Abstract

An article, system and method related to a magnetomechanical marker used to mark stationary assets. Magnetomechanical markers can be arranged in clusters and associated with stationary assets, including assets buried underground. Markers can be associated with an asset by being attached to the asset, arranged in a particular spatial relationship with the asset, or in any other appropriate way. A portable locating device can be used to generate an alternating magnetic field to activate the magnetomechanical marker and thus locate the asset.

Claims

1. A system for locating a pipe buried underground, the system comprising:

a first cluster of magnetomechanical markers disposed on the pipe at a first pipe location;

a second cluster of magnetomechanical markers disposed on the pipe at a second location, wherein each cluster comprises at least two magnetomechanical markers, wherein a distance separating the first location from the second location is greater than a distance separating each magnetomechanical marker within the first cluster; and

a portable locating device, wherein the locating device includes at least a single antenna and a battery, wherein each magneto mechanical marker includes a ferromagnetic material that resonates at its characteristic frequency when interrogated with an alternating magnetic field generated by the portable locating device tuned to the characteristic frequency.

2. The system of claim 1, wherein the first cluster of magnetomechanical markers is arranged in a parallel array.

3. The system of claim 2, wherein a magnetic bias layer polarity of each magnetomechanical marker within the cluster is the same.

4. The system of claim 1, wherein the first cluster of magnetomechanical markers includes a first magnetomechanical marker tuned to a first frequency and a second magnetomechanical marker tuned to a second frequency, wherein the first frequency is different from the second frequency.

5. The system of claim 1, wherein at least one magnetomechanical marker is tuned to a resonant frequency within the range of 57 kHz to 59 kHz.

6. The system of claim 1, wherein a spacing of adjacent magnetomechanical marker clusters provides information regarding the path of the pipe.

7. The system of claim 1, wherein the first cluster of magnetomechanical markers is arranged in an end-to-end configuration.

8. The system of claim 1, wherein the first cluster of magnetomechanical markers is arranged in a side by side configuration.