US20020079902A1 - Sensor for measuring the electrical conductivity of a fluid medium - Google Patents

Sensor for measuring the electrical conductivity of a fluid medium Download PDF

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Publication number
US20020079902A1
US20020079902A1 US09/435,784 US43578499A US2002079902A1 US 20020079902 A1 US20020079902 A1 US 20020079902A1 US 43578499 A US43578499 A US 43578499A US 2002079902 A1 US2002079902 A1 US 2002079902A1
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US
United States
Prior art keywords
sensor
input
excitation coil
signal
measuring
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.)
Abandoned
Application number
US09/435,784
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English (en)
Inventor
Christoph Wieland
Armin Zeller
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.)
Endress and Hauser Conducta GmbH and Co KG
Original Assignee
Endress and Hauser Conducta Gesellschaft fuer Mess und Regeltechnik mbH and Co KG
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 Endress and Hauser Conducta Gesellschaft fuer Mess und Regeltechnik mbH and Co KG filed Critical Endress and Hauser Conducta Gesellschaft fuer Mess und Regeltechnik mbH and Co KG
Assigned to ENDRESS HAUSER CONDUCTA GESELLSCHAFT FUR MESS-UND REGELTECHNIK MBH & CO. reassignment ENDRESS HAUSER CONDUCTA GESELLSCHAFT FUR MESS-UND REGELTECHNIK MBH & CO. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: WIELAND, CHRISTOPH, ZELLER, ARMIN
Publication of US20020079902A1 publication Critical patent/US20020079902A1/en
Priority to US10/434,183 priority Critical patent/US6812709B2/en
Abandoned legal-status Critical Current

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    • 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
    • G01N27/023—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance where the material is placed in the field of a coil

Definitions

  • the present invention relates to an inductively operating sensor for measuring the electrical conductivity of a fluid medium, having an excitation coil, to which an input signal is fed, and a receiver coil coupled with the former via the fluid medium, which provides an output signal, which is a measurement for the conductivity of the fluid medium.
  • Such sensors have an excitation coil which is for example designed as a toroid coil and is fed by an a.c. voltage.
  • a ring-shaped magnetic alternating field is generated in the interior of the excitation coil.
  • a receiver coil which can also be designed as a toroid coil, is arranged at the same level in which the excitation coil also lies. Because of the magnetic alternating field in the excitation coil, mobile ions in the fluid medium generate a ring-shaped current in the fluid medium to be measured, which in turn triggers an output signal in the receiver coil, whose strength is a function of the mobility and concentration of the ions, and therefore of the electrical conductivity of the fluid medium. Customarily the output signal appears as an induction current.
  • Sensors of this type are preferably employed in the food or drug industry for monitoring the production processes in production installations for producing food or drugs.
  • the sensors must always provide an accurate and dependable output signal, so that excessive changes in the conductivity of the medium to be measured can be rapidly detected and a correspondingly rapid reaction takes place in order to be able to prevent deterioration of the food or drugs to be produced.
  • the appropriate reactions to a change in conductivity can be triggered either indirectly by the production crews, or directly by the production installations.
  • the senor In the course of its employment, the sensor can be exposed to strong mechanical and thermal stresses. Because of this, damage to the windings of the excitation coil or the receiver coil can occur in some cases. Leak currents, or even short circuits, can occur between the damaged windings. The output signal can be distorted because of the leak currents between the windings, and a short circuit between the windings renders the entire sensor unusable.
  • the distorted signal is not detected as such by the production personnel, or respectively the production installation.
  • the production personnel, or respectively the production installation assumes that the output signal has detected a changed conductivity of the medium to be measured and reacts accordingly by matching the production processes to the new conductivity values of the medium. Only after some time, or respectively in case of a considerably distorted output signal, will it be possible to detect, for example by means of a probability check, that the output signal is distorted, or respectively that the sensor is defective.
  • the present invention is therefore based on the object of designing and further developing a sensor of the type mentioned at the outset in such a way that it allows an early detection of damage to the windings of the excitation coil or the receiver coil, or respectively of the service cable, which could lead to leak currents or short circuits.
  • the invention proposes, based on a sensor of the type mentioned at the outset, that the sensor has means for measuring a variable signal at the input of the excitation coil.
  • This signal at the input of the excitation coil acts in the same way in case of damage to the service cable of the sensor, which might lead to leak currents or short circuits.
  • the variable signal at the input of the excitation coil thus provides rapid and dependable information regarding the ability of the sensor to function. Damage to the windings of the excitation coil or the receiver coil, or respectively to the service cable of the sensor, which result in leak currents or short circuits, can be detected early and dependably by monitoring this signal at the input of the excitation coil.
  • the production crew can react without delay to such a detected sensor defect. For example, production can initially be stopped in order to prevent the production of defective products. The defective sensor can be exchanged for a new one, and production can then be started again. In addition, it would also be possible to perform a measurement check of the conductivity of the medium to be measured in order to check whether the sensor is actually defective. The shut-off and subsequent restart of production can also be performed directly by the control device of the production installation, without the production crew having an input on this.
  • the senor has a voltage source, which feeds an input voltage to the excitation coil, and that the means for measuring the variable signal pick up the input current at the input of the excitation coil.
  • the means for measuring the input current have a multiplier and measure the voltage dropping across the multiplier. Since the voltage changes proportionally with the input current, it is possible to determine the input current at a sensor designed in this way in a simple manner.
  • the senor has a measured value transducer for receiving the output signal, which is connected with the means for measuring the variable signal at the input of the excitation coil, that the means generate a status signal, which is a function of the measured value of the variable signal at the input of the excitation coil, and that the means feed the status signal to the measured value transducer.
  • the status signal lies within a defined threshold range as long as the sensor functions. However, if the monitored variable signal at the input of the excitation coil steeply increases as a result of damage, the means for measuring the variable signal generate an appropriate status signal which lies outside of the threshold range.
  • the measured value transducer can appropriately react without a time delay to such a status signal, from which it determines the lack of the ability of the sensor to function. As a reaction, the measured value transducer can stop the entire production, for example, so that a production of defective products does not even occur.
  • the measured value transducer corrects the output signal as a function of the strength of the status signal. If damage to the windings of the excitation coil or receiver coil, or respectively of the service cable of the sensor, only results in a slight distortion of the output signal, this will also lead to a small change of the variable signal at the output of the excitation coil.
  • the measured value transducer can react to such a change in the variable signal for example with a corresponding correction of the output signal. By means of this it is possible to continue the assurance of the function free of defects of the sensor.
  • the measured value transducer causes a signal to be issued if the status signal lies outside of a defined threshold range.
  • This report can be merely used to inform the production crew, which can then react accordingly. However, this report can also have the character of an alarm signal, which automatically triggers defined reactions, or respectively stops the production installation.
  • FIG. 1 shows a sensor in accordance with the invention in a preferred embodiment.
  • An inductively operating sensor in accordance with the invention is identified as a whole by 1 in FIG. 1.
  • the sensor 1 is used for measuring the electric conductivity of a fluid medium 2 .
  • the sensor 1 has an excitation coil 3 designed as a toroid coil, which is fed by an alternating voltage U Err .
  • a ring-shaped alternating magnetic field is generated in the interior of the excitation coil 3 .
  • a receiver coil 4 is also arranged on the same level on which the excitation coil 3 is located and is also designed as a toroid coil.
  • a ring-shaped current I Med is generated in the fluid medium 2 to be measured by ions moving in the fluid medium 2 because of the alternating magnetic field in the excitation coil 3 , which in turn triggers an induction current I Ind in the receiver coil 4 .
  • the strength of the induction current I Ind is a function of the mobility and concentration of the ions and therefore of the electric conductivity of the fluid medium 2 .
  • the sensor 1 has means for measuring the input current I Err , which are identified as a whole by the reference numeral 5 .
  • the means 5 for measuring the input current I Err have a multiplier R and measure the voltage U dropping across the multiplier R. Damage to the windings of the excitation coil 3 or the receiver coil 4 , or respectively to the service cable (not represented) of the sensor 1 , which result in leak currents or short circuits, can be detected early and dependably by monitoring the input current I Err of the excitation coil 3 .
  • the sensor 1 it is conceivable for the sensor 1 to have a measured value transducer (not represented) for receiving the induction current I Ind , with which the means 5 for measuring the input current I Err are connected.
  • the means 5 for measuring the input current I Err generate a status signal, which is a function of the measured value of the input current I Err and which is supplied by the means to the measured value transducer.
  • the measured value transducer can correct, for example, the induction current I Ind as a function of the strength of the status signal, so that an error-free function of the sensor 1 is assured in spite of damage to the sensor 1 .
  • the measured value transducer can also cause the issue of an alarm signal, if the status signal lies outside of a defined threshold range.

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)
  • Investigating Or Analyzing Materials By The Use Of Magnetic Means (AREA)
  • Measurement Of Resistance Or Impedance (AREA)
US09/435,784 1998-11-06 1999-11-08 Sensor for measuring the electrical conductivity of a fluid medium Abandoned US20020079902A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US10/434,183 US6812709B2 (en) 1998-11-06 2003-05-09 Sensor for measuring the electrical conductivity of a fluid medium

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19851146A DE19851146B4 (de) 1998-11-06 1998-11-06 Sensor und Verfahren zum Messen der elektrischen Leitfähigkeit eines flüssigen Mediums
DE19851146.9 1998-11-06

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US10/434,183 Continuation US6812709B2 (en) 1998-11-06 2003-05-09 Sensor for measuring the electrical conductivity of a fluid medium

Publications (1)

Publication Number Publication Date
US20020079902A1 true US20020079902A1 (en) 2002-06-27

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Family Applications (2)

Application Number Title Priority Date Filing Date
US09/435,784 Abandoned US20020079902A1 (en) 1998-11-06 1999-11-08 Sensor for measuring the electrical conductivity of a fluid medium
US10/434,183 Expired - Fee Related US6812709B2 (en) 1998-11-06 2003-05-09 Sensor for measuring the electrical conductivity of a fluid medium

Family Applications After (1)

Application Number Title Priority Date Filing Date
US10/434,183 Expired - Fee Related US6812709B2 (en) 1998-11-06 2003-05-09 Sensor for measuring the electrical conductivity of a fluid medium

Country Status (4)

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US (2) US20020079902A1 (de)
EP (1) EP0999441B1 (de)
AT (1) ATE256284T1 (de)
DE (1) DE19851146B4 (de)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20090302856A1 (en) * 2005-09-20 2009-12-10 Endress + Hauser Conducta Gmbh + Co. Kg Plug-In Module for a Liquid or Gas Sensor
CN101629984A (zh) * 2008-07-14 2010-01-20 梅特勒-托利多仪器（上海）有限公司 电磁式溶液电导率测量装置的断路和短路检测方法及装置

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6414493B1 (en) 2001-03-26 2002-07-02 Rosemount Analytical Inc. Toroid conductivity sensor
USRE49221E1 (en) 2002-06-14 2022-09-27 Parker Intangibles, Llc Single-use manifolds for automated, aseptic handling of solutions in bioprocessing applications
US9283521B2 (en) 2002-06-14 2016-03-15 Parker-Hannifin Corporation Single-use manifold and sensors for automated, aseptic transfer of solutions in bioprocessing applications
AU2005205611B2 (en) * 2004-01-15 2010-08-05 The University Of Southern Queensland Method and apparatus for measuring electrical conductivity
US7405572B2 (en) * 2005-05-02 2008-07-29 Invensys Systems, Inc. Non-metallic flow-through electrodeless conductivity sensor and leak detector
US7857506B2 (en) * 2005-12-05 2010-12-28 Sencal Llc Disposable, pre-calibrated, pre-validated sensors for use in bio-processing applications
DE102006025098B4 (de) * 2006-05-19 2008-06-05 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. Sensor zur Ermittlung der elektrischen Leitfähigkeit flüssiger Medien und ein Verfahren zu seiner Herstellung
DE102006025194A1 (de) 2006-05-29 2007-12-06 Endress + Hauser Conducta Gesellschaft für Mess- und Regeltechnik mbH + Co. KG Induktiver Leitfähigkeitssensor
DE102006056174A1 (de) * 2006-11-27 2008-05-29 Endress + Hauser Conducta Gesellschaft für Mess- und Regeltechnik mbH + Co. KG Induktiver Leitfähigkeitssensor
CN101688846B (zh) * 2007-05-31 2013-05-29 恩德莱斯和豪瑟尔测量及调节技术分析仪表两合公司 电感式电导率传感器
DE102008011380A1 (de) * 2008-02-27 2009-09-03 Endress + Hauser Conducta Gesellschaft für Mess- und Regeltechnik mbH + Co. KG Induktiver Messsensor zur induktiven Messung der Leitfähigkeit eines strömenden Mediums
DE102008047960A1 (de) 2008-09-18 2010-03-25 Endress + Hauser Conducta Gesellschaft für Mess- und Regeltechnik mbH + Co. KG Ringspule
DE102008048995A1 (de) 2008-09-25 2010-04-01 Endress + Hauser Conducta Gesellschaft für Mess- und Regeltechnik mbH + Co. KG Induktiver Leitfähigkeitssensor
DE102008048996A1 (de) 2008-09-25 2010-04-01 Endress + Hauser Conducta Gesellschaft für Mess- und Regeltechnik mbH + Co. KG Induktiver Leitfähigkeitssensor
DE102009026403A1 (de) 2009-05-20 2010-11-25 Endress + Hauser Conducta Gesellschaft für Mess- und Regeltechnik mbH + Co. KG Induktive Leitfähigkeits-Messzelle und Verfahren zum Betreiben derselben
DE102009026998A1 (de) * 2009-06-17 2010-12-23 Endress + Hauser Conducta Gesellschaft für Mess- und Regeltechnik mbH + Co. KG Leitfähigkeitssensor mit Umschaltung zwischen Sende- und Empfangsspule
DE102011002766A1 (de) 2011-01-17 2012-07-19 Endress + Hauser Conducta Gesellschaft für Mess- und Regeltechnik mbH + Co. KG Messanordnung zur Bestimmung einer elektrischen Leitfähigkeit einer Messflüssigkeit
DE102011102698A1 (de) * 2011-05-20 2012-11-22 Continental Automotive Gmbh Vorratsbehälter für eine Flüssigkeit und Verfahren zum Messen der elektrischen Leitfähigkeit einer Flüssigkeit
DE102011079572A1 (de) 2011-07-21 2013-01-24 Endress + Hauser Conducta Gesellschaft für Mess- und Regeltechnik mbH + Co. KG Gradiometer zur Bestimmung der elektrischen Leitfähigkeit eines in einem Behältnis enthaltenen Mediums
DE102012112388A1 (de) 2012-12-17 2014-07-03 Endress + Hauser Conducta Gesellschaft für Mess- und Regeltechnik mbH + Co. KG Induktiver Leitfähigkeitssensor und Verfahren zu dessen Herstellung
DE102014109366A1 (de) * 2014-07-04 2016-01-07 Endress + Hauser Conducta Gesellschaft für Mess- und Regeltechnik mbH + Co. KG Induktiver Leitfähigkeitssensor zum Messen der spezifischen elektrischen Leitfähigkeit eines Mediums
DE102014116415A1 (de) 2014-11-11 2016-05-12 Endress + Hauser Conducta Gesellschaft für Mess- und Regeltechnik mbH + Co. KG Gradiometer zur Bestimmung einer elektrischen Leitfähigkeit eines Mediums
DE102015104217A1 (de) 2015-03-20 2016-09-22 Endress + Hauser Conducta Gesellschaft für Mess- und Regeltechnik mbH + Co. KG Messsystem zum Bestimmen der spezifischen elektrischen Leitfähigkeit
DE102016119508A1 (de) 2016-10-13 2018-04-19 Krohne Messtechnik Gmbh Leitfähigkeitssensor und Verfahren zur Bestimmung der elektrischen Leitfähigkeit eines flüssigen Mediums
DE102021117833A1 (de) 2021-07-09 2023-01-12 Endress+Hauser Flowtec Ag Leitfähigkeitssensor
DE102021117837A1 (de) 2021-07-09 2023-01-12 Endress+Hauser Conducta Gmbh+Co. Kg Leitfähigkeitssensor

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20090302856A1 (en) * 2005-09-20 2009-12-10 Endress + Hauser Conducta Gmbh + Co. Kg Plug-In Module for a Liquid or Gas Sensor
US8847602B2 (en) * 2005-09-20 2014-09-30 Endress + Hauser Conducta Gesellschaft für Mess- und Regeltechnik mbH + Co. KG Plug-in module for a liquid or gas sensor
CN101629984A (zh) * 2008-07-14 2010-01-20 梅特勒-托利多仪器（上海）有限公司 电磁式溶液电导率测量装置的断路和短路检测方法及装置

Also Published As

Publication number Publication date
DE19851146B4 (de) 2008-12-11
EP0999441B1 (de) 2003-12-10
DE19851146A1 (de) 2000-05-11
ATE256284T1 (de) 2003-12-15
EP0999441A1 (de) 2000-05-10
US20030197499A1 (en) 2003-10-23
US6812709B2 (en) 2004-11-02

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AS Assignment

Owner name: ENDRESS HAUSER CONDUCTA GESELLSCHAFT FUR MESS-UND

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:WIELAND, CHRISTOPH;ZELLER, ARMIN;REEL/FRAME:010386/0048

Effective date: 19991028

STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION