EP1869438A1 - Dispositif et procede pour controler un echantillon solide oblong - Google Patents

Dispositif et procede pour controler un echantillon solide oblong

Info

Publication number
EP1869438A1
EP1869438A1 EP06705378A EP06705378A EP1869438A1 EP 1869438 A1 EP1869438 A1 EP 1869438A1 EP 06705378 A EP06705378 A EP 06705378A EP 06705378 A EP06705378 A EP 06705378A EP 1869438 A1 EP1869438 A1 EP 1869438A1
Authority
EP
European Patent Office
Prior art keywords
electrode
measuring
capacitor
output signal
protective
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Withdrawn
Application number
EP06705378A
Other languages
German (de)
English (en)
Inventor
Philipp Ott
Peter Schmid
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Uster Technologies AG
Original Assignee
Uster Technologies AG
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 Uster Technologies AG filed Critical Uster Technologies AG
Publication of EP1869438A1 publication Critical patent/EP1869438A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
    • G01N33/36—Textiles
    • G01N33/365—Filiform textiles, e.g. yarns
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
    • G01N27/22—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating capacitance
    • G01N27/226—Construction of measuring vessels; Electrodes therefor

Definitions

  • the present invention is in the field of testing with capacitive means of solid, elongated, preferably textile structures such as card sliver, roving, yarn or fabric. It relates to a device and a method for the investigation of a solid, elongate test material, according to the preambles of the independent claims. Such an investigation may, for example, have as its objective the detection of foreign substances or the detection of changes in mass per unit length.
  • a reference capacitor is used in a preferred embodiment of the device disclosed in EP-O '924' 513 A1 simultaneously with the actual measuring capacitor. This can be arranged by adding a third, parallel to the two measuring capacitor plates Capacitor plate are formed, wherein the three capacitor plates are connected together to form a capacitive bridge. Typical dimensions of the capacitor plates are approx. 7 mm x 7 mm, typical plate distances approx. 2 mm.
  • the distances between the measuring part electrode and the protective electrodes have to be increased.
  • this reduces the desired protective effect of the protective electrodes, because it makes the electric field at the edges of the measuring part electrode inhomogeneous.
  • a measuring head with such enlarged electrodes claimed more space, which is a disadvantage in terms of use.
  • the invention is based on the idea to operate with at least one of the protective electrodes active guarding, d. H. to apply a time-varying voltage to the at least one protective electrode.
  • the device according to the invention for testing a solid, elongate test material comprises a measuring capacitor with a measuring part electrode and at least one protective electrode electrically insulated from the measuring part electrode, means for applying an alternating voltage to the measuring capacitor for generating an alternating electric field in the measuring capacitor and a passage opening for the test material in the measuring capacitor , Which passage opening from the alternating electric field can be acted upon.
  • At least one of the at least one guard electrode is set up for active guarding.
  • an AC voltage can be applied to the at least one protective electrode in such a way that the at least one protective electrode is at least AC-connected at approximately the same potential as the measuring partial electrode.
  • the invention also includes the use of active guarding by means of at least one protective electrode in the capacitive examination of a solid, elongate test material.
  • the test material is exposed to an alternating electric field in a measuring capacitor with a measuring part electrode and at least one protective electrode electrically insulated from the measuring part electrode.
  • Active guarding is operated with at least one of the at least one protective electrodes.
  • an alternating voltage is applied to the at least one protective electrode in such a way that the at least one protective electrode is at least alternating voltage at approximately the same potential as the measuring partial electrode.
  • the active guarding according to the invention prevents the undesired effects of the parasitic capacitances between the measuring part electrode and the protective electrodes. It allows much smaller designs of the measuring head.
  • FIG. 1 shows a first embodiment of a measuring head for the device according to the invention in a perspective view
  • FIG. 2 shows curves of electric field lines in a measuring capacitor (a) according to the prior art
  • Figures 3-5 three further embodiments of a
  • Measuring head for the device according to the invention in perspective views
  • FIG. 1 A first embodiment of a measuring head 1 for the device according to the invention is shown in Figure 1 in a perspective view.
  • the measuring head 1 essentially comprises a measuring capacitor 2.
  • this is a planar two-plate capacitor with a first, essentially flat capacitor plate 21 and a second, essentially flat capacitor plate 22.
  • the capacitor plates 21, 22 are each approximately 0.8 mm thick, consist for. B. made of brass and can to achieve a higher Abrasion resistance z. B. be coated with nickel.
  • the two capacitor plates 21, 22 are separated by an approximately 1-3 mm, preferably about 1.5-2.0 mm thick air gap, which forms a passage opening 26 for a solid, elongated fürgut 9.
  • the scholar 9 can z. B. be a yarn. It is preferably moved in the longitudinal direction x through the passage opening 26 and thereby exposed to an alternating electric field 29 (see FIG. 2 (b)) generated between the two capacitor plates 21, 22.
  • the measuring capacitor 2 includes at least one protective electrode 24.1, 24.2 for reducing the influence of edge effects of the alternating electric field 29 on an output signal of the measuring capacitor 2.
  • the second capacitor plate 22 is divided into three mutually electrically isolated sub-electrodes 23, 24.1, 24.2: a central measuring part electrode 23 and two outer part electrodes 24.1, - 24.2, which form two protection electrodes.
  • insulating material 25.1, 25.2, z As ceramic or plastic, so that the three sub-electrodes 23, 24.1, 24.2 mechanically form a unit, just the capacitor plate 22.
  • the lengths in the x direction of the individual parts 23, 24.1, 24.2, 25.1, 25.2 can z. B. as follows: protective electrodes 24.1. 24.2 each approx. 1 mm, insulation material 25.1, 25.2 each approx. 0.5 mm, measuring part electrode 23 approx. 4 mm.
  • the second Capacitor plate 22 has a total length of about 7 mm; their height in z-direction can also be about 7 mm.
  • the dimensions of the first capacitor plate 21 are preferably substantially the same.
  • the aspect ratios of measuring part electrode 23 and protective electrodes 24.1, 24.2 can be optimized depending on the application. In any case, the length of the insulating material 25.1, 25.2 should be as small as possible in order to ensure an optimum protective effect through the protective electrodes 24.1, 24.2 and to keep the geometric dimensions of the measuring head 1 small.
  • the first capacitor plate 21 and the three sub-electrodes 23, 24.1, 24.2 of the second capacitor plate 22 are contacted by separate electrical leads 27.1-27.4, so that individually applied to them electrical voltage and / or can be tapped.
  • the electrical circuit diagram will be discussed in more detail with reference to FIGS. 6 and 7.
  • Figure 2 shows a side view of a snapshot of progressions of electric field lines of an electric
  • FIG. 3 shows, in an analogous representation as in FIG. 1, a second embodiment of a measuring head 1 for the device according to the invention. From the embodiment of
  • FIG 1 shows this embodiment, by the two
  • Protective electrodes 24.1, 24.2 along a front edge of the second capacitor plate 22 are interconnected. This results in a C-shaped protective electrode 24, the lower and upper leg are in the input or output region of the passage opening 26.
  • the central connection part of the C-shaped guard electrode 24 offers various
  • Measuring capacitor 2 and thus reduces the dependence of Output signal from the position of the yarn 9 in the z direction. Third, it reduces the sensitivity of the measurement to contact (eg, by an operator) of the measuring head 1 from the front.
  • FIG. 3 A further development of the embodiment of FIG. 3 is drawn in FIG. Here, the two legs of the C-shaped guard electrode 24 were bonded together along a trailing edge of the second capacitor plate 22, thereby closing the C into a rectangle or ring.
  • the advantages described with reference to FIG. 3 are present here to an even greater degree.
  • FIG. 5 A fourth embodiment of a measuring head 1 for the device according to the invention is shown in FIG. 5. This measuring head
  • 1 includes a measuring capacitor 2, as he on the occasion of
  • FIG. 1 has been described, and in addition a Reference capacitor 3.
  • the middle capacitor plate 22 is common to both capacitors 2, 3.
  • the middle, common capacitor plate 22 is the one which includes the protective electrodes 24.1, 24.2.
  • the reference capacitor 3 is used to eliminate interference caused by external influences such as air temperature or humidity.
  • the middle capacitor plate 22 may also be formed according to the embodiments of Figure 3 or 4, or in another way.
  • FIG. 5 An electrical circuit diagram of a first embodiment of the device according to the invention with measuring capacitor 2 and reference capacitor 3 (see Fig. 5) is shown in FIG.
  • the device includes an AC generator 4 for applying an AC voltage to the measuring capacitor 2 and to the reference capacitor 3.
  • the frequency of the applied AC voltage is preferably between 1 MHz and 100 MHz, z. B. 10 MHz.
  • the capacitors 2, 3 are preferably followed by an impedance converter 5, with whose input line 51 the measuring part electrode 23 is connected.
  • An output line 59 of the impedance converter 5 connects the impedance converter 5 with a detector circuit 6.
  • the detector circuit 6 is used for analogous detection of the output signal of the capacitors 2, 3. In the embodiment of Figure 6, it essentially performs a multiplication of the output signal of the measuring capacitor 2 with the voltage applied to the capacitors 2, 3 AC signal. The thus demodulated output signal is output on an output line 69 of the detector circuit 6.
  • the impedance converter 5 adjusts the high impedance of the measuring capacitor 2 of the low impedance of the detector circuit 6.
  • the demodulated output signal is fed to the output line 69 of an evaluation circuit 7.
  • the evaluation circuit 7 determines therefrom the actual result of the test and outputs an output signal on an output line 79 of the device.
  • the result may be, for example, measuring changes in mass per unit length or detecting foreign matter in the tested yarn 9. With suitable evaluation methods, it is even possible to determine the quantitative proportion of foreign substances and possibly the material of the foreign substances.
  • the evaluation circuit 7 may be formed as an analog electrical circuit or as a digital circuit with a processor. Methods and devices for the capacitive detection and quantification of solid foreign substances in textile test material 9 are known from EP-O '924' 513 A1 and can also be adopted for the present invention.
  • EP-O '924' 513 Al and in particular the Paragraphs [0022] - thereof are incorporated by reference into the present specification.
  • the impedance converter 5 is formed as a collector circuit.
  • the input line 51 is connected to a base 53 of a transistor 52, preferably a bipolar transistor.
  • a collector 54 of the Bipolar transistor 52 is applied a constant operating voltage V C c.
  • An emitter 55 of the bipolar transistor 52 is connected to the output line 59.
  • Various resistors 56-58 serve to adjust the operating point of the impedance converter 5.
  • active guarding is used, i. H. an alternating voltage is applied to the protective electrodes 24.1, 24.2, in such a way that they are at least alternating current at approximately the same potential as the measuring sub-electrode 23.
  • This is achieved in the embodiment of FIG. 6 by the output line 59 of the collector circuit 5 with the protective electrodes 24.1 , 24.2 is electrically connected.
  • the output signal of the collector circuit 5 can be used as an input signal for the protective electrodes 24.1, 24.2, because the collector circuit 5 has a small output resistance.
  • FIG. 7 shows an alternative to the collector circuit 5 of FIG. 6, namely a transimpedance amplifier circuit 8 having an operational amplifier 82 acting as an impedance converter.
  • a noninverting input + of the operational amplifier 82 is electrically connected to the measuring part electrode 23 by means of an input line 81.
  • An inverting input - the operational amplifier 82 is on the one hand via a Feedback line 83 with an output line 89, on the other hand electrically connected to the protective electrodes 24.1, 24.2.
  • this alternative can have the disadvantages that the operational amplifier is comparatively expensive and - at least in the embodiments currently available on the market - either has too low an input impedance or too narrow a bandwidth, so that it will be overwhelmed by high excitation frequencies in the MHz range could.
  • the invention is not limited to the embodiments described above. So it is z. B. conceivable to provide more than two protective electrodes in the measuring capacitor 2. By dividing the second capacitor plate 22 into a plurality of measuring part electrodes and a corresponding plurality of protective electrodes, the local resolution of the measurement can be increased. It is also possible for more than one capacitor plate to be equipped with one or more protective electrodes. It is also not necessary to use measuring capacitors with flat capacitor plates for the invention; other capacitor forms are also possible. The embodiments described above may also be combined with each other. LIST OF REFERENCE NUMBERS

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Biochemistry (AREA)
  • General Physics & Mathematics (AREA)
  • Analytical Chemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Textile Engineering (AREA)
  • Electrochemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Food Science & Technology (AREA)
  • Medicinal Chemistry (AREA)
  • Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)

Abstract

L'invention concerne un dispositif pour contrôler un échantillon (9) solide oblong. Ce dispositif comprend un condensateur de mesure (2), pourvu d'une électrode partielle de mesure (23) et d'électrodes de protection (24.1, 24.2) isolées électriquement de cette dernière, ainsi que des moyens (4) servant à appliquer une tension alternative aux bornes du condensateur de mesure (2) dans le but de produire un champ électrique alternatif dans ce dernier. Les électrodes de protection (24.1, 24.2) sont conçues pour assurer une protection active dans la mesure où elles sont maintenues, sur le plan de la tension alternative, au même potentiel que l'électrode partielle de mesure (23). Grâce à cette protection active, il est possible de contrôler des échantillons (9) de différentes épaisseurs au moyen d'une seule et même tête de mesure (1). Ainsi, le bruit de signal est réduit, le signal de sortie est, dans une large mesure, indépendant de la position de l'échantillon (9) dans le sens transversal et la tête de mesure (1) présente de faibles dimensions géométriques.
EP06705378A 2005-04-05 2006-03-06 Dispositif et procede pour controler un echantillon solide oblong Withdrawn EP1869438A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CH6212005 2005-04-05
PCT/CH2006/000138 WO2006105676A1 (fr) 2005-04-05 2006-03-06 Dispositif et procede pour controler un echantillon solide oblong

Publications (1)

Publication Number Publication Date
EP1869438A1 true EP1869438A1 (fr) 2007-12-26

Family

ID=36297222

Family Applications (1)

Application Number Title Priority Date Filing Date
EP06705378A Withdrawn EP1869438A1 (fr) 2005-04-05 2006-03-06 Dispositif et procede pour controler un echantillon solide oblong

Country Status (5)

Country Link
US (1) US20080111563A1 (fr)
EP (1) EP1869438A1 (fr)
JP (1) JP2008534988A (fr)
CN (1) CN101166970A (fr)
WO (1) WO2006105676A1 (fr)

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Publication number Priority date Publication date Assignee Title
US20060267321A1 (en) * 2005-05-27 2006-11-30 Loadstar Sensors, Inc. On-board vehicle seat capacitive force sensing device and method
DE102008031130A1 (de) * 2008-07-02 2010-01-21 Sipra Patententwicklungs- Und Beteiligungsgesellschaft Mbh Kapazitiv arbeitende Sensoreinheit zur Überwachung der Qualität von Fasermaterial und damit ausgerüstete Maschine zur Herstellung von Maschenware
DE102008031108A1 (de) 2008-07-02 2010-01-21 Sipra Patententwicklungs- Und Beteiligungsgesellschaft Mbh Kapazitiv arbeitende Sensoreinheit zur Überwachung der Qualität von Fasermaterial und damit ausgerüstete Maschine zur Herstellung von Maschenware
CH699774A2 (de) 2008-10-16 2010-04-30 Uster Technologies Ag Kapazitive messschaltung.
CH699752A1 (de) * 2008-10-16 2010-04-30 Uster Technologies Ag Vorrichtung und verfahren zum ausmessen einer kapazität.
CH699753A1 (de) * 2008-10-16 2010-04-30 Uster Technologies Ag Vorrichtung und verfahren zum ausmessen einer kapazität.
DE102008059176A1 (de) 2008-11-25 2010-05-27 Sipra Patententwicklungs- Und Beteiligungsgesellschaft Mbh Kapazitiv arbeitende Sensoreinheit zur Überwachung der Qualität von Fasermaterial und damit ausgerüstete Maschine zur Herstellung von Maschenware
KR101669418B1 (ko) * 2009-11-12 2016-10-27 삼성전자주식회사 서리 착상 감지 장치 및 그를 냉각 시스템 및 냉장고
DE102010003710A1 (de) * 2010-04-08 2011-10-13 Endress + Hauser Gmbh + Co. Kg Verfahren und Vorrichtung zur Bestimmung eines in einem Adsorbermaterial enthaltenen Anteils eines adsorbierten Stoffes
CH703736A1 (de) * 2010-09-07 2012-03-15 Uster Technologies Ag Justierung einer textilen messvorrichtung.
FR2978828B1 (fr) 2011-08-02 2013-09-06 Snecma Capteur multi-electrode pour determiner la teneur en gaz dans un ecoulement diphasique
GB201306914D0 (en) * 2013-04-16 2013-05-29 Univ Southampton Apparatus for electrically measuring individual particles flowing in a liquid
GB201306913D0 (en) 2013-04-16 2013-05-29 Univ Southampton A method of electrically measuring the size of individual particles flowing in a liquid
JPWO2015029904A1 (ja) * 2013-09-02 2017-03-02 アルプス電気株式会社 水分検出装置
WO2016149842A1 (fr) * 2015-03-20 2016-09-29 Uster Technologies Ag Ensemble d'électrodes pour le test capacitif d'une matière textile allongée
EP4314794A1 (fr) * 2021-03-22 2024-02-07 Uster Technologies AG Dispositif d'analyse capacitive d'un objet d'essai allongé et mobile

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US3039051A (en) * 1959-08-12 1962-06-12 Zellweger Uster Ag Apparatus for gaging textile materials
GB1097760A (en) * 1965-04-27 1968-01-03 Ilford Ltd Testing material for irregularities of thickness
DE4105857C2 (de) * 1991-02-25 1994-07-07 Claas Ohg Vorrichtung zur Messung eines Massestromes
DE59200669D1 (de) * 1991-02-25 1994-12-01 Claas Ohg Vorrichtung zur Messung eines Massestromes mit einem Messkondensator.
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Also Published As

Publication number Publication date
WO2006105676A1 (fr) 2006-10-12
CN101166970A (zh) 2008-04-23
JP2008534988A (ja) 2008-08-28
US20080111563A1 (en) 2008-05-15

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