EP0542939A1 - PROCEDE POUR LA SURVEILLANCE DE L'APTITUDE AU FONCTIONNEMENT DE SONDES DE pH - Google Patents

PROCEDE POUR LA SURVEILLANCE DE L'APTITUDE AU FONCTIONNEMENT DE SONDES DE pH

Info

Publication number
EP0542939A1
EP0542939A1 EP19920908009 EP92908009A EP0542939A1 EP 0542939 A1 EP0542939 A1 EP 0542939A1 EP 19920908009 EP19920908009 EP 19920908009 EP 92908009 A EP92908009 A EP 92908009A EP 0542939 A1 EP0542939 A1 EP 0542939A1
Authority
EP
European Patent Office
Prior art keywords
probe
measuring
analog
voltage
electrode
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Withdrawn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
EP19920908009
Other languages
German (de)
English (en)
Inventor
Heinz-Jürgen BRINKMANN
Stefan Hellinge
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.)
Ingold Messtechnik AG
Original Assignee
Ingold Messtechnik 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 Ingold Messtechnik AG filed Critical Ingold Messtechnik AG
Publication of EP0542939A1 publication Critical patent/EP0542939A1/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Withdrawn legal-status Critical Current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
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/26—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
    • G01N27/416—Systems
    • G01N27/4163—Systems checking the operation of, or calibrating, the measuring apparatus
    • G01N27/4165—Systems checking the operation of, or calibrating, the measuring apparatus for pH meters

Definitions

  • the invention relates to a method for monitoring the functionality of pH probes according to the preamble of claim 1.
  • Electrode systems mainly glass electrodes, are being used to an increasing extent for measuring the hydrogen ion concentration in liquids, in particular for monitoring chemical and biological processes, for example in microbiological processes, and in food technology.
  • the increasing use of electrodes for the purposes mentioned leads to increasing requirements with regard to measuring accuracy in long-term use.
  • continuous monitoring of the condition of the electrodes used is necessary, since, for example, damage to the ion-sensitive membrane, contamination of the diaphragm, a line break and / or a short circuit within the electrode impair the Measurement accuracy.
  • EP-A-0 241 601 it is known from EP-A-0 241 601 to use an alternating voltage to monitor the state and function of the measuring electrode and / or the reference electrode of an electrode system for potentiometric measurements.
  • three different circuits are set up, which can be closed alternately, namely a first circuit between the measuring electrode and an auxiliary electrode also immersed in the measuring solution, a second circuit between the reference electrode and the auxiliary electrode and one third circuit between the measuring electrode and the reference electrode, the latter serving to determine the ion concentration in the measuring solution.
  • EP-A2-0 419 769 discloses a method for the continuous monitoring of an electrode system for potentiometric measurements, in which the monitoring is carried out using symmetrical bipolar current pulses.
  • the period of the current pulses is freely selectable and can be set differently according to the required test accuracy.
  • the symmetrical bipolar current pulses are generated by means of a voltage divider circuit. This method is characterized by a high measurement accuracy, but requires a relatively large amount of circuitry.
  • the object of the invention is to provide a simple and easy to carry out method for error detection in pH electrodes, in which the effort is low in terms of both the mechanical structure and the electronics required for the evaluation and also with a known device for automatic or partially automatic cleaning and / or calibration of pH electrodes can be combined or used to control them.
  • the measuring probe can remain in the measuring medium during the entire test procedure and must be removed, not even briefly. In this way, interruptions and disruptions in the course of the process to be monitored can be completely avoided or at least limited to a minimum.
  • the figure shows a functional diagram of a circuit arrangement for carrying out the method.
  • the figure shows a circuit arrangement 2 to a network 4 of a first capacitor 6, a second capacitor 8 and a first resistor 10.
  • Other constituents • the switching circuit 2, an analog-to-digital converter 12 which is controlled by a microprocessor 14, a Measuring probe 18 immersed in a measuring medium 16 with a measuring electrode 20 and a reference electrode 22, further a second resistor 24 and an impedance converter 26.
  • the microprocessor 14 has an analog output 28 and a serial interface 30.
  • the procedure is such that a rectangular pulse variable in amplitude and duration is controlled by means of the analog-digital converter 12 via the analog output 28 of the microprocessor 14 via the network 4, and its duration and amplitude are controlled by means of the microprocessor 14 are high-impedance to the measuring probe 18.
  • Switching on the second resistor 24 prevents a current from flowing through the dielectric of the first capacitor 6 into the high-resistance input of the impedance converter 26.
  • the voltage U j changed by the probe impedance. of the measuring probe 18 to be tested and compared with an experimentally or arithmetically determined target value, for example the voltage U Q of an intact, preferably new, measuring probe.
  • the voltage U Q can be determined experimentally by measuring a new or intact measuring probe in an analog manner using the same circuit arrangement. It • However , there is also the possibility of calculating the voltage U Q computationally, for example on the basis of tables and / or on the basis of manufacturer's information. The measured values can either be taken directly and read by a voltmeter or recorded by this. However, the measured values are advantageously fed into the microprocessor 14 and processed there. You can then either be fed via the analog output of the microprocessor 14 to the analog-digital converter 12 and used to control it, or fed via the serial interface 30 into a cleaning and / or calibration device and for controlling an automatic or semi-automatic cleaning and / or calibration method can be used.
  • the comparison between the measured voltage u ⁇ and the target value, i.e. the voltage U Q , allows direct conclusions to be drawn about existing disturbing factors, as mentioned above, both in terms of quality and quantity, and allows a continuous error analysis without the laborious expansion of the measuring probe and its Withdrawal from the measuring medium and thus without disturbing the process flow, for the monitoring of which the measuring probe is used.
  • the method can be carried out simply and easily both in laboratory operation and in the industrial field and allows the use of an uncomplicated circuit arrangement.
  • Circuit arrangement network first capacitor second capacitor first resistor analog-to-digital converter microprocessor measuring medium measuring probe measuring electrode reference electrode second resistor impedance converter analog output interface

Landscapes

  • Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Molecular Biology (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)

Abstract

Il est décrit un procédé pour la détection de dérangements, lequel permet de manière simple et sans problèmes de détecter différentes sources de dérangements au cours de la surveillance continue d'un système à électrodes. Selon ce procédé, on envoie au moyen d'un convertisseur analogique-numérique (12) par l'intermédiaire du réseau (4) une impulsion rectangulaire variable en amplitude et en durée à la sonde de mesure (18) plongeant dans un fluide dont le pH est à mesurer (16). La sonde mesure la tension U1 modifiée par l'impédance de la sonde et la compare avec une valeur de consigne correspondant à une sonde de mesure intacte. Des écarts entre les valeurs mesurées obtenues et la valeur de consigne prédéterminée permettent de tirer des conclusions quant à l'état des électrodes. Il ne faut plus démonter la sonde de mesure (18), et elle peut rester pendant le déroulement tout entier du procédé dans le fluide dont le pH est à mesurer. Une perturbation du processus à surveiller peut ainsi être complètement ou au moins partiellement évitée.
EP19920908009 1991-06-07 1992-04-10 PROCEDE POUR LA SURVEILLANCE DE L'APTITUDE AU FONCTIONNEMENT DE SONDES DE pH Withdrawn EP0542939A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CH1716/91 1991-06-07
CH171691 1991-06-07

Publications (1)

Publication Number Publication Date
EP0542939A1 true EP0542939A1 (fr) 1993-05-26

Family

ID=4216932

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19920908009 Withdrawn EP0542939A1 (fr) 1991-06-07 1992-04-10 PROCEDE POUR LA SURVEILLANCE DE L'APTITUDE AU FONCTIONNEMENT DE SONDES DE pH

Country Status (2)

Country Link
EP (1) EP0542939A1 (fr)
WO (1) WO1992021962A1 (fr)

Families Citing this family (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19628033C1 (de) * 1996-07-11 1997-11-13 Fraunhofer Ges Forschung Verfahren und Vorrichtung zur Driftkompensation bei chemischen Sensoren
FR2762395B1 (fr) * 1997-04-16 1999-07-09 Zellweger Analytics Dispositif et procede de controles de l'integrite des electrodes d'un systeme de mesure potentiometrique
WO2000014523A2 (fr) * 1998-09-09 2000-03-16 Cominco Ltd. Appareil de surveillance de l'exploitabilite d'un capteur electrochimique
EP1143239A1 (fr) * 2000-04-04 2001-10-10 Metrohm Ag Procédé de surveillance de la qualité de capteurs de mesures électrochimiques et dispositif de mesure avec un capteur électrochimique
ATE412888T1 (de) 2005-07-14 2008-11-15 Mettler Toledo Ag Signalübertragungsvorrichtung für eine messsonde sowie übertragungsverfahren
EP1818672B1 (fr) 2006-02-14 2012-08-29 Mettler-Toledo AG Dispositif de mesure et procédé destinés au fonctionnement du dispositif de mesure
CN101135662B (zh) 2006-08-30 2010-11-10 梅特勒-托利多仪器（上海）有限公司 电位分析电极测量的方法及装置
EP1936367A1 (fr) * 2006-12-22 2008-06-25 Mettler-Toledo AG Procédé et dispositif destinés à la surveillance et/ou la détermination de l'état d'une sonde de mesure
US10234417B2 (en) 2016-02-02 2019-03-19 Msa Technology, Llc Sensor interrogation with fast recovery
EP3594671B1 (fr) 2018-07-10 2022-09-07 ABB Schweiz AG Procédé permettant de surveiller la fonction de détection d'un capteur potentiométrique et ensemble de capteur potentiométrique correspondent

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4189367A (en) * 1978-10-19 1980-02-19 Leeds & Northrup Company Method for testing ion selective electrodes in continuous measuring systems
EP0241601B1 (fr) * 1986-04-15 1990-02-07 Yokogawa Europe B.V. Appareil pour tester l'intégrité d'une électrode dans un système d'électrodes de mesures potentiométriques
US4912417A (en) * 1989-02-21 1990-03-27 Fisher Scientific Company Measurement of pH and specific ion concentration
CH678978A5 (fr) * 1989-09-29 1991-11-29 Mettler Toledo Ag

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9221962A1 *

Also Published As

Publication number Publication date
WO1992021962A1 (fr) 1992-12-10

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