WO2015099982A1 - Appareil et système de marqueur magnéto-mécanique - Google Patents

Appareil et système de marqueur magnéto-mécanique Download PDF

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Publication number
WO2015099982A1
WO2015099982A1 PCT/US2014/068812 US2014068812W WO2015099982A1 WO 2015099982 A1 WO2015099982 A1 WO 2015099982A1 US 2014068812 W US2014068812 W US 2014068812W WO 2015099982 A1 WO2015099982 A1 WO 2015099982A1
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WO
WIPO (PCT)
Prior art keywords
marker
housing
mmr
spacer elements
magneto
Prior art date
Application number
PCT/US2014/068812
Other languages
English (en)
Inventor
David P. Erickson
Steven E. Turch
Original Assignee
3M Innovative Properties Company
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 3M Innovative Properties Company filed Critical 3M Innovative Properties Company
Publication of WO2015099982A1 publication Critical patent/WO2015099982A1/fr

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
    • G01V15/00—Tags attached to, or associated with, an object, in order to enable detection of the object

Definitions

  • Magneto-mechanical resonators are well known and have been used in retail security applications for decades.
  • magneto-mechanical resonators are also suitable for buried infrastructure due to their low cost, low profile and flexible components. They can be stand-alone markers or physically attached to an underground pipe or utility. They can be used to identify a buried asset and its location accurately. For example, see US 2012/068823; US 2012/0325359; and US 2013/0099790, each of which is incorporated herein by reference in its entirety.
  • a housing for a magneto-mechanical marker comprises a base portion, a cover portion, and a separator portion disposed between the base portion and the cover portion.
  • the separator portion provides a physical separation between at least one resonator strip and a magnetic bias.
  • the separator portion includes a plurality of spacer elements protruding towards the cover portion.
  • the spacer elements have a curved or pointed shape in cross section and are configured to reduce the amount of surface contact with the at least one resonator strip.
  • the cover portion further includes a plurality of protrusions that protrude towards the separator portion.
  • Fig. 1 A is an exploded view of a magneto mechanical marker according to a first aspect of the invention.
  • Fig. IB is a side, partial cross-section view of the magneto mechanical marker of Fig. 1A.
  • Fig. 1C is a side, partial cross-section view of a magneto mechanical marker according to another aspect of the invention.
  • Figs. 2 A and 2B show distance test data for bias up and bias down samples from Tables 1-4.
  • Figs. 3A and 3B show Q test data for bias up and bias down samples from Tables 1-4.
  • Figs. 4 A and 4B show frequency test data for bias up and bias down samples from Tables 1-4.
  • Figs. 5A and 5B show signal strength test data for bias up and bias down samples from Tables 1-4.
  • a magneto mechanical resonator (MMR) marker for use in locating and identifying buried assets is described herein.
  • MMR magneto mechanical resonator
  • Such a magneto-mechanical resonator can be suitable for buried infrastructure due to its low cost, low profile and flexible components.
  • MMR marker can be a stand-alone marker, it can be physically attached to an underground asset, such as a pipe or other utility, or it can be attached to another device, such as caution or warning tape, located at or near the underground asset.
  • Figs. 1A and IB show a first aspect of the present invention, an MMR marker 100, in an exploded view and a side view, respectively.
  • MMR marker 100 includes a housing 110 that encloses at least one magneto restrictive material, referred to as a resonator strip 150, and a bias magnet 170 therein.
  • a resonator strip 150 can be included in marker 100.
  • a conventional MMR marker is designed to couple to an external magnetic field at a particular frequency and convert the magnetic energy into mechanical energy, in the form of oscillations of the resonator strip(s). The radiated energy from the oscillating strip(s) can then be detected by a detection device.
  • MMR marker housing 110 provides a structure for more consistent performance, especially when a non-annealed magneto restrictive material is used as the resonator strip(s) 150.
  • a resonator strip material that is not annealed a down-web curl can be formed. This curl can also be affected by strip cutting or slitting. This curled shape may result in performance issues caused by damped resonation, possibly due to a varying distance between the bias magnet and the one or more resonator strips, especially at the ends of the strips, or due to rotation effects of the marker that can occur in use.
  • MMR marker housing 110 can also house an annealed or other treated resonator strip. An annealed resonator strip material does not exhibit such a pronounced down web curl.
  • the housing 110 includes a base portion 114, a cover portion 112, and a separator portion 120 disposed between the base portion 114 and the cover portion 112.
  • the separator portion 120 provides a physical separation between the at least one resonator strip 150 and a magnetic bias material 170.
  • the separator portion 120 includes a plurality of spacer elements 125, formed on pedestals 122. The spacer elements 125 protrude towards the cover portion 112. The spacer elements 125 are configured to reduce the amount of surface contact with resonator strip(s) 150.
  • the spacer elements 125 are spread apart, with a spacer elements located at the lengthwise ends of the resonator strip(s) 150. In this manner, the resonator strip(s) can be suspended on a limited number of very small contact points, thus substantially reducing potential contact due to the magnetic field produced by the bias material 170 pulling the resonator strip(s) 150 against the surface of the separator portion 120.
  • the spacer elements 125 can be placed closer together, where each spacer element can be located near a central portion of the housing 110.
  • an MMR marker 100' can include spacer elements 125 placed closer together, where each spacer element can be located near a central portion of the housing 110.
  • cover 112 can include a corresponding number of downward protrusions 115 that are configured to oppose the spacer elements 125.
  • the spacer element 125 has a curved or rounded (e.g., bump) shape in cross section.
  • the spacer element 125 can have a pointed shape in cross section.
  • the shape and size of the spacer elements can all be the same or they can each be different.
  • the shape and size of the spacer elements can be configured to accommodate resonator strips of different curls and lengths.
  • the shape and size of the downward protrusions 115 can all be the same or they can each be different.
  • the center downward protrusion is slightly smaller than the end protrusions, in this case, to minimize touch points of the tag when the tag is flipped over in use (e.g, the "bias up" position - explained further below).
  • Resonator strip 150 comprises a ferromagnetic material with magnetostrictive properties, such as a magnetic amorphous alloy or crystalline material such as Metglas 2826 MB, 2605SA1 or 2605S3A made by Metglas, Inc. of Conway, S.C.
  • Resonator strip 150 can also comprise a similar material, such as those made by Vacuumschmelze GmbH of Hanau, Germany.
  • the physical dimensions, such as the length, width, and thickness, of the resonator strip(s) can be chosen based on the desired response frequency.
  • the resonator strip material is magnetically biased by a magnetic bias material 170, such as a permanent magnet or a magnetically hard or semi-hard metal strip.
  • a magnetic bias material 170 such as a permanent magnet or a magnetically hard or semi-hard metal strip.
  • magnetically hard magnetic bias material 170 that is not readily changeable can be utilized herein because its bias characteristics are unlikely to change when buried underground.
  • the magnetic bias layer 170 can be made from any magnetic material that has sufficient magnetic remanence when magnetized to appropriately bias the resonators, and sufficient magnetic coercivity so as to not be magnetically altered in normal operating environments.
  • a commercially available magnetic material such as ArnokromeTM III from The Arnold
  • the magnetic bias layer 170 can have dimensions similar to those of resonator strip(s) 150. As with linear or bar magnets, magnetic bias layer 170 has magnetic poles, one at each end.
  • the housing 110 can be formed from a plastic or any other non-conductive material, such as PVC, or other polymers.
  • the housing can be formed using a conventional vacuum forming process.
  • the housing material can maintain its shape and spacing around the resonator strip and bias material.
  • the housing and component material can be formed as a non-rigid or flexible structure, either as a result of material composition or thickness of the housing walls.
  • the spacer elements 125 can be formed as non-rigid or flexible structures.
  • the MMR marker 100 can be placed within a protective capsule or outer housing designed to withstand rugged conditions.
  • the protective capsule can be formed from a rugged material such as high density polyethylene (HDPE).
  • HDPE high density polyethylene
  • MMR marker 100 can be disposed on or near an underground asset, such as a pipe, conduit, or other facility.
  • an MMR marker can be a stand-alone marker, it can be physically attached to an underground asset, such as a pipe or other utility, or it can be attached to another device, such as caution or warning tape, located at or near the underground asset.
  • the MMR markers described herein can be utilized in non- underground environments, such as for use in locating and identifying above-ground assets otherwise hidden from view (such as in a container or within a building wall, ceiling, or floor).
  • the MMR markers can be specifically designed to operate at different frequencies which are associated with unique asset types such as different utility infrastructure (e.g., water, waste water, electric, telephone/cable/data, and gas).
  • asset types such as different utility infrastructure (e.g., water, waste water, electric, telephone/cable/data, and gas).
  • the MMR marker has a frequency range of from about 34 kHz to about 80 kHz. It is noted that for some applications, for example, for plastic pipe locating, frequency shifts are not desirable where multiple MMR markers may be combined to achieve additional detection depth. Accordingly, the MMR markers disclosed herein can be clustered (for additional depth), without demonstrating substantial frequency shifts. In addition, especially for pipe locating applications, the MMR markers can be employed to provide not only asset location, but also asset directionality.
  • MMR marker 100 can be utilized as part of a sterilization indicator system that provides time, temperature, and/or chemical information.
  • MMR marker 100 can be utilized as part of a perishable (e.g., food spoilage) indicator system that provides time and temperature information.
  • MMR marker 100 can be utilized as part of a leak detection system that provides leak information for above or below ground utilities.
  • the MMR marker can further incorporate an embedded antenna to wirelessly communicate sensor information.
  • the MMR marker can be designed to be physically affected by changing conditions so that a signal response may vary over time or conditions, indicating certain information to the user.
  • MMR marker 100 In operation, MMR marker 100 resonates at its characteristic frequency when interrogated with an alternating magnetic field tuned to this frequency. Energy is stored in the marker during this interrogation period in the form of both magnetic and mechanical energy (manifested as resonator vibrations). When the interrogation field is removed, the resonator continues to vibrate and releases significant alternating magnetic energy at its resonant frequency that can be remotely sensed with a suitable detector. Such a response alerts a locating technician to the presence of MMR marker 100.
  • frequency can be impacted as the markers/resonators are allowed to move closer and farther away from the biasing field.
  • the magnetic near fields drop off rapidly as a function of distance (1/r 3 ).
  • the embodiments of the invention described herein reduce the amount of distance the resonator strips can fall away from the magnetic bias material, thus minimizing this affect.
  • the detector may not be configured as a broad band interrogation device.
  • frequency shifts are not desirable for multiple reasons where multiple MMR markers may be combined to achieve additional detection depth. Accordingly, for that implementation, minimizing frequency shifts can improve performance. Differences in the frequencies of tags that are being combined must be very close in frequency to achieve improved performance.
  • this characteristic is a measure of how long the MMR
  • marker/resonator strip(s) continues to resonate after the interrogating field is turned off.
  • frictional forces can be reduced.
  • dampening of the resonation resulting in higher Q.
  • the cost of locating equipment, speed of the locating device, the distance the MMR marker is positioned from the locating device, and the amount of power provided to the MMR marker all affect the system performance.
  • An exemplary portable locating device such as described in US 2012/068823, incorporated by reference above, can comprise a single antenna that is used to generate an electromagnetic field and to detect a response of the MMR marker 100.
  • one antenna could be used for generating an electromagnetic field and a second antenna could be used for detecting the response of the MMR marker to the generated field.
  • the locating device can be battery powered for better portability.
  • An integrated display can provide a user with a variety of information about located MMR markers and the assets that the MMR markers are associated with. For example, the display can provide information about marker and asset depth, direction, or other information about the MMR markers.
  • One exemplary portable locating device is the 3MTM DynatelTM 1420 Locator, distributed by 3M Company of St. Paul, Minn.
  • the locating device firmware can be programmed so as to tune the locator antenna to radiate a particular, or several particular desired frequencies.
  • MMR marker 100 can be associated with an asset buried underground.
  • An article including an MMR marker 100 can also be associated with an asset.
  • An MMR marker 100 or an article including MMR marker 100 can be associated with an asset so that it is physically attached to the asset, incorporated into the asset, in the same vertical plane as the asset, whether disposed above or below the asset, or offset from the asset, including being offset to the side of the asset.
  • the MMR marker or article may be within a 30 cm, 60 cm or 1 meter radius of the asset.
  • a single MMR marker can be used to identify an asset.
  • multiple MMR markers, arranged in series, parallel, or in clusters can be utilized. Clusters can be generally arranged so that the signals from multiple MMR markers are additive.
  • the MMR markers can be oriented so the magnetic polarity of each marker's magnetic bias layer is the same.
  • the magnetic north poles can generally face the same direction and the magnetic south poles can face the same direction as each other, and in the opposite direction of the north poles.
  • each MMR marker can be spaced an appropriate distance from each other.
  • the magnetic bias layer of one marker can influence a neighboring marker, causing a shift in resonant frequency.
  • long distances between two neighboring or adjacent MMR markers can diminish the received signal amplitude advantages from grouping the tags, for example, as the locating/interrogation device may be placed outside of the range of a neighboring tag.
  • the resonator materials were selected to operate at 41.4 kHz and were supplied by Metglas, Inc. of Conway, S.C. Each marker included two resonator strips, with a first strip being 12mm wide and a second strip being 10mm wide. The length of each strip was selected based on its material properties and was approximately 53mm. The bias was approximately 47mm long.
  • Test Sample 1 10 sample metal sets, with each metal set comprising a 12 mm resonator strip, a 10mm resonator strip and a biasing magnet were placed in a housing that did not include spacer elements formed on the separator layer.
  • the test samples were first measured in a bias "down" orientation (i.e., the bias magnet is disposed below the resonator strip (such as is shown in Fig. 1 A)) and then those same 10 sample markers were measured in a bias "up” orientation (i.e., the bias magnet is disposed above the resonator strip (such that the marker is flipped with respect to the orientation shown in Fig. 1A)).
  • Test Sample 2 the same 10 sample metal sets used in the above experiment, were each placed in a housing that included spacer elements formed on the separator layer (similar to the configuration shown in Fig. 1A). These 10 sample markers were first measured in a bias "down” orientation and then those same 10 sample markers were measured in a bias "up” orientation.
  • the separator layers for both Test Sample 1 and Test Sample 2 had a thickness of about 1.5 mm.
  • the detection distance was measured using a detector/locator device designed specifically for use with the tested MMR markers. This measurement corresponds to the distance between the locator end and the MMR marker where the signal strength drops below a predetermined threshold that is calibrated to be 10 dB above the environment noise floor. For example, for Test Sample 1, the average detection distance is about 32 inches (81.28 cm) for bias down and 39 inches (99.06 cm) for bias up. For Test Sample 2, the average detection distance is about 38 inches (96.5 cm) for bias down and 39 inches (99.06 cm) for bias up. This data indicates substantial advantages are realized in the "bias down" condition, which appears to be more impacted by the minimized surface contact between the spacer element and the resonator strip(s).
  • frequency corresponds to the frequency of the emitted signal from the MMR marker after excitation.
  • the average measured frequency was about 41.6 KHz for bias down and about 41.5 KHz for bias up.
  • the average measured frequency was about 41.4 KHz for both bias down and for bias up.
  • a final characteristic measured was Q-value, which corresponds to the length of time the marker continues to resonate after the alternating magnetic field provided by the locating device is removed.
  • the Q-value also impacts the amount of energy needed to be transmitted to the MMR marker in order to maximize the signal response.
  • Tables 1 to 4 provide information relating to read distance, frequency, signal strength, and Q calculations for bias up and bias down orientations for each of the Test Sample sets 1 and 2. The results for these tests are shown in Figs. 2A, 2B (Distance), Figs. 3A, 3B (Q), Figs. 4A, 4B (Frequency), and Figs. 5A, 5B (Signal Strength).
  • a commercial function generator was used to generate the signal at a known frequency, amplitude, and was connected to a custom-wound transmit coil.
  • the receive coil which is disposed inside the transmit coil, was connected to an oscilloscope.
  • the tests used an industry standard communications protocol/bus to communicate from the oscilloscope and function generator.
  • the inclusion of spacer elements as an integral part of the separator layer provides better detection range independent of MMR marker orientation, more consistent frequency results when the MMR markers are flipped, better Q and better overall performance.
  • an MMR marker can be a standalone marker, it can be physically attached to an underground asset, such as a pipe or other utility, or it can be attached to another device, such as caution or warning tape, located at or near the underground asset.
  • an MMR marker described herein can be utilized in non-underground environments, such as for use in locating and identifying above-ground assets otherwise hidden from view (such as in a container or within a building wall, ceiling, or floor).

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  • Physics & Mathematics (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Geophysics (AREA)
  • Geophysics And Detection Of Objects (AREA)

Abstract

L'invention concerne un boîtier pour un marqueur magnéto-mécanique, qui comprend une partie de base, une partie de couvercle et une partie de séparateur disposée entre la partie de base et la partie de couvercle. La partie de séparateur fournit une séparation physique entre au moins une bande de résonateur et une polarisation magnétique, la partie de séparateur comprenant une pluralité d'éléments d'espacement faisant saillie vers la partie de couvercle, les éléments d'espacement ayant une forme incurvée ou pointue en coupe transversale configurée pour réduire la quantité de contact de surface avec la ou les bandes de résonateur.
PCT/US2014/068812 2013-12-23 2014-12-05 Appareil et système de marqueur magnéto-mécanique WO2015099982A1 (fr)

Applications Claiming Priority (2)

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US201361919950P 2013-12-23 2013-12-23
US61/919,950 2013-12-23

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WO2015099982A1 true WO2015099982A1 (fr) 2015-07-02

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20020171548A1 (en) * 2001-05-16 2002-11-21 Wing Ho Apparatus for electronic article surveillance tag pollution reduction
US20090195386A1 (en) * 2006-02-15 2009-08-06 Johannes Maxmillian Peter Electronic article surveillance marker
US20100259391A1 (en) * 2006-08-07 2010-10-14 Gadonniex Dennis M Electronic Article Surveillance Marker
US20120068823A1 (en) * 2010-09-22 2012-03-22 3M Innovative Properties Company Magnetomechanical markers for marking stationary assets
US20130099790A1 (en) * 2011-10-21 2013-04-25 3M Innovative Properties Company Multi-axis marker locator

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20020171548A1 (en) * 2001-05-16 2002-11-21 Wing Ho Apparatus for electronic article surveillance tag pollution reduction
US20090195386A1 (en) * 2006-02-15 2009-08-06 Johannes Maxmillian Peter Electronic article surveillance marker
US20100259391A1 (en) * 2006-08-07 2010-10-14 Gadonniex Dennis M Electronic Article Surveillance Marker
US20120068823A1 (en) * 2010-09-22 2012-03-22 3M Innovative Properties Company Magnetomechanical markers for marking stationary assets
US20130099790A1 (en) * 2011-10-21 2013-04-25 3M Innovative Properties Company Multi-axis marker locator

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