EP2158464A2 - Kapazitive kraftsensoranordnung - Google Patents
Kapazitive kraftsensoranordnungInfo
- Publication number
- EP2158464A2 EP2158464A2 EP08758041A EP08758041A EP2158464A2 EP 2158464 A2 EP2158464 A2 EP 2158464A2 EP 08758041 A EP08758041 A EP 08758041A EP 08758041 A EP08758041 A EP 08758041A EP 2158464 A2 EP2158464 A2 EP 2158464A2
- Authority
- EP
- European Patent Office
- Prior art keywords
- conductor
- sensor
- dielectric
- sensor arrangement
- arrangement according
- Prior art date
- Legal status (The legal status 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 status listed.)
- Withdrawn
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L1/00—Measuring force or stress, in general
- G01L1/14—Measuring force or stress, in general by measuring variations in capacitance or inductance of electrical elements, e.g. by measuring variations of frequency of electrical oscillators
Definitions
- the present invention relates to the preamble claimed and thus relates to sensors responsive to applied forces.
- TDR time domain reflectometry
- a device for leak detection in pipes is known.
- a fluid conducting leak detection conduit surrounded around its periphery with a flexible fluid permeable conductive material and comprising a series of parallel insulated electrical conductors extending generally longitudinally along the Conductor and wrapped around the outside of said flexible conductive material, the insulated electrical conductors having bare conductor elements exposed in the adjacent regions of the insulated conductor material at the location of the insulated conductor material adjacent to the flexible conductive material.
- the object of the present invention is to provide new products for commercial use.
- the present invention thus proposes, in a first aspect, a sensor having a conductor arrangement and an inter-conductor dielectric for detecting local sensor impedance changes in response to external forces, wherein the conductor arrangement is provided comprising elongated conductor strips, between which the inter-conductor dielectric is arranged compressible insulation medium.
- the intermediate conductor dielectric is still completely isolated even in the compressed state. It should be noted, however, that it would be possible to first observe an impedance change during compression, which is due to a continuous change in the conductor geometry, in order then to effect a contacting of the conductors in a final state, such as per se out of state known to the art. In such a case, an end position of the compression movement could be displayed. In the preferred variant, however, this is precisely what is prevented because, as a rule, local contacting of conductors results in Art strong changes in impedance can be obtained that quantitative measurements are affected elsewhere.
- the intermediate conductor dielectric is protected in a preferred variant against water and / or moisture absorption or against the inclusion of any fluids that can lead to changes in impedance, which are not due to force; Mention may be made here, for example, of measurements in or on chemical containers in which a swelling effect caused by chemicals could occur and that the thickness of the intermediate conductor dielectric could change.
- the protection against such fluids can be done in different ways. It is possible to use an intermediate conductor dielectric which has no or only closed pores, so that no fluids can penetrate into the intermediate conductor and this is protected per se. Alternatively and / or additionally, it is possible to cover the overall arrangement of conductors and intermediate conductor dielectric, which offers several advantages.
- the conductors are better protected against corrosion and possibly abrasion when inserting a sensor into an opening or recess;
- changes in the environment for example due to soil moisture, can not lead to a change in the measured values if, for example, a stronger discharge to ground along the cable would occur due to moisture.
- intermediate conductor dielectric formed as a compressible insulating medium, which is protected against water and / or moisture absorption
- intermediate conductor dielectric intended for moisture absorption.
- the interposer dielectric layer of the present invention formed as a compressible insulating medium is preferably sandwiched between two conductor strips. This results in particularly stable sensors that are easy to install.
- the intermediate conductor dielectric will be elastically compressible or only at higher levels
- Loads have a plastic deformation or a significant hysteresis.
- the use of such intermediate conductor dielectrics is advantageous because, for example, low vibrations of the substrate are easier to detect and, moreover, there are a multiplicity of applications in which the alternating load behavior has to be investigated, for example in rail construction for railways, in bridges and the like.
- the senor may have very considerable lengths. It can easily be manufactured and used for lengths well over a meter.
- the essential limitation of the sensor length results, on the one hand, from the ever present transverse attenuation of the high-frequency measurement or reflection pulse running along the conductor arrangement and interference from the occurrence of multiple reflections, for example between two sensor locations changed in impedance by external forces but spaced apart from one another. Nevertheless, it will be appreciated that a sensor can have several decameters in length. In particular, measurements in long tunnels, tension bridges and the like are thus possible.
- a plastic in particular a foamed plastic, is used as the intermediate conductor dielectric, wherein the plastic foaming causes the compressibility.
- a plastic hermetically surrounding the conductors is typically preferred.
- - s - Protection is also claimed for the use of a time domain reflectometry sensor, particularly as described above in general or preferred form to quantify deformations and mechanical stresses.
- Examples of applications include excavation enclosures, determination of embankment and soil deformations, pressure and deformation measurements on components for structural safety assessment, damage and fatigue determination for long-term measurements, in particular in underground mining, preferably in moisture distribution corrected manner, in particular for separation between environmental conditions such as Humidity changes, etc. associated signals and changes due to z. Tectonic rock pressures and the like. This is z. B. advantageous if slipping endangered slopes should be observed len to deliver a long-term behavioral prognosis, which is readily possible due to the readability of the measurements obtained with the present sensor and the large sensor lengths.
- the use of the sensor arrangement for detecting pressure distributions with regard to orientation and strength and for determining moisture distributions in a continuous or quasi-continuous manner and with time resolution is mentioned as being particularly preferred.
- inter-conductor dielectrics that are sufficiently temperature-stable to be used in deep wells or well below ground for the measurement purposes mentioned. It is possible to determine deformation and pressure profiles with a high information density, processes coupled with moisture such as swelling, shrinkage, crack pattern and / or relief, in particular if moisture is measured in parallel and / or alternatingly.
- the measurements can be automated without great equipment expense, which is particularly preferred for monitoring purposes, the sensors are also inexpensive to produce and it is readily possible to create sensor configurations that are particularly adapted to a particular task, such as moisture at a given pressure is detected , an adjustment is made with regard to the operating temperature, an adjustment with respect to the expected
- Loads on the sensor is made by choosing the intermediate conductor dielectric, a load distribution to avoid
- temperature-resistant or chemical-resistant sensors are used, which in addition to geotechnical application possibilities significantly expand the spectrum towards industrial monitoring in plant operation.
- Fig. 1 shows a sensor arrangement of the present invention
- FIG. 2 shows time domain reflection signals obtained at different local loads of a sensor according to FIG. 1, measured once from the left and once from the right side;
- FIG. Fig. 3 shows an example of a sensor hysteresis at
- a sensor 1 generally designated 1, comprises a ladder assembly of two conductors 2a, 2b between which an inter-conductor dielectric 3 is provided to detect local sensor impedance changes in response to external forces represented by force vector f, the conductor assembly is formed by elongated conductor strips 2a, 2b, between which the insectsdielektri- kum is arranged as a compressible insulation medium 3.
- the sensor 1 is formed in the present case as a sensor for detecting the local distribution of deformations and mechanical pressures over a longer distance of several meters. It is strip-shaped with a width of, for example, about 2 cm and a thickness of about 2.5 cm formed here. In this case, it has, via the conductors 2a, 2b, an enveloping layer 4 extending outward beyond the conductor edge, which is welded or otherwise sealed at the edges and which is made stiffer than the intermediate conductor dielectric layer 3.
- the conductors 2a, 2b are led out of the end of the sensor and connected for contacting with a coaxial cable, cf. 5, wherein the connection point should not be charged in use, but may be provided with a strain relief and the like.
- the coaxial cable will be routed to a time domain reflectometer in use.
- the conductors 2a, 2b may be copper strips or copper braids formed over the entire width of the sensor arrangement or may be formed from one or more wires.
- the training is as a copper strip; the use of other conductor materials such as aluminum, stainless steel and the like may be mentioned.
- the spacing of the conductors 2a, 2b is constant over the entire length of the sensor in the unloaded state, cf. d in Figure 1.
- the intermediate conductor dielectric 3 is formed in the present case as a closed cell, compressible plastic having an at least largely compression-independent dielectric constant. It is preferred if the inter-conductor dielectric has no piezoelectric properties or has the same.
- the inter-conductor dielectric 3 is arranged as a continuous layer between conductors 2a, 2b and isolates them from one another in each state of the sensor, that is, both in the unloaded state and in compression.
- the inter-conductor dielectric is hermetically encapsulated or at least substantially protected from the ingress of moisture or other swelling or dielectric constant-change fluids; the stiffness of the cladding layer is such that point loads on the sensor result in compression of the inter-conductor dielectric extending over a greater length.
- the use of the sensor arrangement of FIG. 1 is carried out after installation or introduction into a layer in which forces act in one direction of the surface normal of the intermediate layer medium 3.
- a sensor strip of a given length, here of 1 m at four different points (1, 2, 3, 4 in FIG. 2) along the sensor is loaded with different weights.
- the load is varied over the course of the experiment, compare the "load sequence" table, which shows the kilogram load during the test.
- time domain reflectometer It is determined with a time domain reflectometer, as the sensor relies on the task of a steeply sloping voltage pulse at the different loads at different Jobs answers.
- the time domain reflectometer is connected once (upper figure) on the left and once (middle figure) on the right side of the sensor. The difference of the signals from the left and right side terminals is shown in Figure 2 below.
- the impedance that is to say the characteristic impedance between conductors 2a, 2b
- the impedance is constant over the entire sensor length. If a load is exerted on the sensor at one or more points, for example at position 2 with up to 50 kilos, clear impulse reflections result, which are recognizable in the diagrams. These impulse reflections have their cause in the compression of the insulating intermediate conductor medium, which leads to a change in the conductor geometry, in this case to a compression of the conductors 2a to 2b, but without touching them.
- FIG. 3 shows how a sponge rubber as intermediate conductor dielectric leads to hysteresis.
- the deformation is shown at different loads and a subsequent relief, in the right half of the figure is shown how the duration of an injected pulse varies depending on a load or discharge.
- a hysteresis occurs in the used intermediate conductor dielectric.
- other intermediate conductor media except sponge rubber with lower hysteresis, are preferred.
- FIG 4 a first sensor with square intermediate conductor medium 3 'is shown, in the middle of which a first conductor 2d extends, which is not wide here, but is designed as a wire.
- a first conductor 2d extends, which is not wide here, but is designed as a wire.
- two further conductor wires 2e, 2f are arranged, which lie freely on the outer sides. It can thus be used to measure impulse responses when applying voltage pulses to the pair of conductors (2d 2e), (2d 2f) and (2e 2f).
- the impulse response of the sensor to pairs (2d 2e) and (2d 2f) respectively indicates a deformation in a different direction.
- the sensor is therefore sensitive to direction.
- the impedance ie the characteristic impedance of a pulse propagating along the conductor pair (2e 2f)
- the impedance ie the characteristic impedance of a pulse propagating along the conductor pair (2e 2f)
- the properties of the surrounding soil and thus be dependent on the substrate moisture. It is thus possible by simple measurement of different conductor pairs to determine both the direction of force and the soil moisture. This can be advantageous for many applications.
- the sensor arrangement of FIG. 4 above provides a remedy insofar as several conductors are spirally wound there via an intermediate conductor medium formed here. It can thus be a measurement against the inner conductor, also shown done. A twist is not critical here. By determining the location along which a deformation occurs occurs, then can be closed simultaneously on direction.
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Geophysics And Detection Of Objects (AREA)
- Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)
- Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)
- Measurement Of Resistance Or Impedance (AREA)
Abstract
Description
Claims
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE102007022039A DE102007022039B4 (de) | 2007-05-08 | 2007-05-08 | Sensoranordnung |
PCT/DE2008/000783 WO2008135040A2 (de) | 2007-05-08 | 2008-05-08 | Kapazitive kraftsensoranordnung |
Publications (1)
Publication Number | Publication Date |
---|---|
EP2158464A2 true EP2158464A2 (de) | 2010-03-03 |
Family
ID=39868649
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP08758041A Withdrawn EP2158464A2 (de) | 2007-05-08 | 2008-05-08 | Kapazitive kraftsensoranordnung |
Country Status (4)
Country | Link |
---|---|
US (1) | US20110037483A1 (de) |
EP (1) | EP2158464A2 (de) |
DE (2) | DE102007022039B4 (de) |
WO (1) | WO2008135040A2 (de) |
Families Citing this family (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE102009011278B4 (de) * | 2009-03-05 | 2017-04-20 | Imko Micromodultechnik Gmbh | Sonde sowie Vorrichtung zur Ermittlung der Materialfeuchte oder Leitfähigkeit eines Mediums |
ES2376453B1 (es) * | 2010-02-25 | 2013-01-29 | Micromag 2000 S.L. | Sistema sensor capacitivo para dispositivos de protección perimetral. |
EP2746729A1 (de) | 2012-12-20 | 2014-06-25 | GN Store Nord A/S | Anordnung und Verfahren zur Bestimmung einer Kapazitätsänderung |
US9429463B2 (en) | 2013-03-04 | 2016-08-30 | International Road Dynamics, Inc. | System and method for measuring moving vehicle information using electrical time domain reflectometry |
DE102014222485B4 (de) | 2014-11-04 | 2019-11-21 | Technische Universität Dresden | Verzerrungsdetektion von Bauteilen |
DE102016210615A1 (de) * | 2016-06-15 | 2017-12-21 | Leoni Kabel Gmbh | Vorrichtung, Versorgungsleitung für eine solche, Sensorleitung und Verfahren zur Torsionsmessung |
CN108008198B (zh) * | 2017-12-01 | 2019-10-22 | 广东电网有限责任公司佛山供电局 | 一种计及地网温度的冲击接地电阻测量方法 |
DE102018204173A1 (de) * | 2018-03-19 | 2019-09-19 | Leoni Kabel Gmbh | Messanordnung zur Überwachung eines biegeflexiblen Strangs und biegeflexibler Strang sowie Verfahren zur Überwachung eines biegeflexiblen Strangs |
DE102018204176A1 (de) * | 2018-03-19 | 2019-09-19 | Leoni Kabel Gmbh | Koaxialleitung, Messanordnung und Verfahren zur Messung eines Umgebungseinflusses bei einer Koaxialleitung |
DE102018204184A1 (de) * | 2018-03-19 | 2019-09-19 | Leoni Kabel Gmbh | Verfahren zur Überwachung eines Versorgungssystems eines Roboters |
WO2021231047A1 (en) * | 2020-05-14 | 2021-11-18 | Raymond & Lae Engineering, Inc. | Hydrocarbon leak detection cable |
Family Cites Families (14)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
AT355836B (de) * | 1977-02-10 | 1980-03-25 | Semperit Ag | Kondensator zur messung von kraeften |
DE3236056A1 (de) * | 1982-09-29 | 1984-03-29 | Siemens AG, 1000 Berlin und 8000 München | Detektormatte |
DE3642088A1 (de) * | 1986-12-10 | 1988-06-23 | Wolfgang Brunner | Anordnung zur messung von kraftverteilungen |
US4910998A (en) * | 1987-05-01 | 1990-03-27 | Andrew Corporation | Fluid detection system and method having a coaxial cable with solid, stranded dielectric elements |
DE4021664A1 (de) * | 1990-07-07 | 1992-01-16 | Wrede & Niedecken Verwaltung | Vorrichtung und verfahren zur ermittlung von leckagen an isolierten, ein stroemungsmedium beinhaltenden beziehungsweise fuehrenden bauteilen |
US5203202A (en) | 1992-02-25 | 1993-04-20 | W. L. Gore & Associates, Inc. | Apparatus for detecting leaks in circuits |
DE4322859C2 (de) * | 1993-07-08 | 1996-01-11 | Sepp Mueller | Einrichtung zur Langzeit-Lecküberwachung an doppelwandigen Gefäßsystemen, insbesondere doppelwandigen Tankböden |
JP2913022B2 (ja) * | 1996-08-19 | 1999-06-28 | 農林水産省農業研究センター所長 | 土壌水分計測方法及び土壌水分計測用プローブ |
US5905194A (en) * | 1997-11-21 | 1999-05-18 | Strong; Thomas P. | Pipe line with integral fault detection |
US6956381B2 (en) * | 2001-10-12 | 2005-10-18 | The Board Of Regents Of University And Community College System Of Nevada On Behalf Of The Desert Research Institute | Flexible probe for measuring moisture content in soil |
US6889557B2 (en) * | 2002-02-11 | 2005-05-10 | Bechtel Bwxt Idaho, Llc | Network and topology for identifying, locating and quantifying physical phenomena, systems and methods for employing same |
DE10220478A1 (de) * | 2002-05-07 | 2003-11-27 | Framatome Anp Gmbh | Elektrische Durchführung und Verwendung der elektrischen Durchführung |
US7196529B2 (en) * | 2003-05-06 | 2007-03-27 | Profile Technologies, Inc. | Systems and methods for testing conductive members employing electromagnetic back scattering |
US6967584B2 (en) * | 2003-07-28 | 2005-11-22 | Senstar-Stellar Corporation | Integrated sensor cable for ranging |
-
2007
- 2007-05-08 DE DE102007022039A patent/DE102007022039B4/de not_active Expired - Fee Related
-
2008
- 2008-05-08 EP EP08758041A patent/EP2158464A2/de not_active Withdrawn
- 2008-05-08 WO PCT/DE2008/000783 patent/WO2008135040A2/de active Application Filing
- 2008-05-08 US US12/599,045 patent/US20110037483A1/en not_active Abandoned
- 2008-05-08 DE DE112008001742T patent/DE112008001742A5/de not_active Withdrawn
Non-Patent Citations (1)
Title |
---|
See references of WO2008135040A2 * |
Also Published As
Publication number | Publication date |
---|---|
WO2008135040A3 (de) | 2009-02-26 |
DE102007022039B4 (de) | 2009-07-09 |
WO2008135040A2 (de) | 2008-11-13 |
US20110037483A1 (en) | 2011-02-17 |
DE112008001742A5 (de) | 2010-04-08 |
DE102007022039A1 (de) | 2008-11-20 |
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Legal Events
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RIN1 | Information on inventor provided before grant (corrected) |
Inventor name: BECKER, ROLF Inventor name: SCHUHMANN, RAINER Inventor name: SCHLAEGER, STEFAN Inventor name: BIEBERSTEIN, ANDREAS Inventor name: WOERSCHING, HOLGER Inventor name: HUEBNER, CHRISTOF Inventor name: SCHEUERMANN, ALEXANDER |
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RIN1 | Information on inventor provided before grant (corrected) |
Inventor name: BECKER, ROLF Inventor name: SCHUHMANN, RAINER Inventor name: SCHLAEGER, STEFAN Inventor name: BIEBERSTEIN, ANDREAS Inventor name: WOERSCHING, HOLGER Inventor name: HUEBNER, CHRISTOF Inventor name: SCHEUERMANN, ALEXANDER |
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