WO2001067082A1 - Electrochemical detecting element - Google Patents

Electrochemical detecting element Download PDF

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Publication number
WO2001067082A1
WO2001067082A1 PCT/DE2001/000079 DE0100079W WO0167082A1 WO 2001067082 A1 WO2001067082 A1 WO 2001067082A1 DE 0100079 W DE0100079 W DE 0100079W WO 0167082 A1 WO0167082 A1 WO 0167082A1
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WO
WIPO (PCT)
Prior art keywords
protective tube
fiber material
ceramic fiber
sensor element
gas
Prior art date
Application number
PCT/DE2001/000079
Other languages
German (de)
French (fr)
Inventor
Helmut Weyl
Jens Stefan Schneider
Frank Stanglmeier
Original Assignee
Robert Bosch Gmbh
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 Robert Bosch Gmbh filed Critical Robert Bosch Gmbh
Publication of WO2001067082A1 publication Critical patent/WO2001067082A1/en

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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
    • G01N27/403—Cells and electrode assemblies
    • G01N27/406—Cells and probes with solid electrolytes
    • G01N27/407—Cells and probes with solid electrolytes for investigating or analysing gases
    • G01N27/4077—Means for protecting the electrolyte or the electrodes

Definitions

  • the inflow and outflow openings 24 are arranged such that the measuring gas penetrates into the measuring gas space 23 perpendicular to the axis of the sensor element, while in the exemplary embodiment shown in FIG. 2, the measuring gas also penetrates into the measuring gas space 23 parallel to the axis of the sensor element 20.
  • the ceramic fiber material 21 is arranged between the two walls of the double-walled protective tube 22 in such a way that the measuring gas only reaches the measuring gas space 23 after it has flowed through the ceramic fiber material 21.

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  • 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)
  • Measuring Oxygen Concentration In Cells (AREA)

Abstract

The invention relates to an electrochemical detecting element for determining gas constituents and/or gas concentrations in gas mixtures which comprises a sensor element (20) that is surrounded by a protective tube (22). The protective tube (22) provides access to the sensor element (20) for a gas to be analyzed. A ceramic fiber material (21) is located in the protective tube (22) and is arranged at a distance from the sensor element (20) in the protective tube (22).

Description

Elektrochemischer MeßfühlerElectrochemical sensor
Stand der TechnikState of the art
Die Erfindung geht aus von einem elektrochemischen Meßfühler nach dem Oberbegriff des Anspruchs 1.The invention relates to an electrochemical sensor according to the preamble of claim 1.
Aus der EP 0 587 350 Bl ist ein Gassensor der gattungsgemäßen Art zur Bestimmung derEP 0 587 350 B1 describes a gas sensor of the generic type for determining the
Sauerstoffkonzentration in einem Meßgas bekannt, der ein Sensorelement und ein Schutzrohr aufweist. In das Schutzrohr sind Locher eingebracht, die den Zutritt des Meßgases zum Sensorelement erlauben. Weiterhin ist der Raum zwischen dem Schutzrohr und dem Sensorelement mit einem Isoliermaterial gepackt, das beispielsweise aus einem gasdurchlässigen, keramischen Fasermaterial besteht. Bei dieser Anordnung tritt das Problem auf, daß der Kontakt des Isoliermaterials zu einer auf dem Sensorelement aufgebrachten Elektrode aufgrund der verwendungstypisch auftretenden Erschütterungen zu einem Abrieb fuhrt, der die bestimmungsgemaße Funktion des Gassensors stört. Daneben können bei einerOxygen concentration in a measuring gas is known, which has a sensor element and a protective tube. Holes are made in the protective tube, which allow the sample gas to enter the sensor element. Furthermore, the space between the protective tube and the sensor element is packed with an insulating material which consists, for example, of a gas-permeable, ceramic fiber material. With this arrangement, the problem arises that the contact of the insulating material with an electrode applied to the sensor element leads to abrasion due to the vibrations which typically occur in use and which disturbs the intended function of the gas sensor. In addition, at one
Verunreinigung des Isoliermaterials bei entsprechenden Potentialverhaltnissen Fehlerstrome von der Elektrode über das Isoliermaterial abfließen, die die bestimmungsgemaße Funktion des Gassensors stören. Der Kontakt des im Betrieb verunreinigten Isoliermaterials mit dem Sensorelement kann weiterhin zu Verunreinigungen der Oberflache des Sensorelements fuhren.Contamination of the insulation material with appropriate potential conditions, fault currents flow from the electrode via the insulation material, which interfere with the intended function of the gas sensor. The contact of the insulating material contaminated during operation with the sensor element can continue to lead to contamination of the surface of the sensor element.
Vorteile der ErfindungAdvantages of the invention
Der erfindungsgemaße Gassensor mit den kennzeichnenden Merkmalen des unabhängigen Anspruchs hat gegenüber dem Stand der Technik den Vorteil, daß Abrieb, Verunreinigung der Oberflache des Sensorelements und Fehlerstrome vermieden werden.The gas sensor according to the invention with the characterizing features of the independent claim has the advantage over the prior art that abrasion, contamination of the surface of the sensor element and fault currents are avoided.
Ist weiterhin das keramische Fasermaterial so angeordnet, daß das Meßgas zumindest zum überwiegenden Teil nur durch das keramische Fasermaterial zum Sensorelement strömen kann, so ergibt sich der weitere Vorteil, daß im Meßgas mitgefuhrtes Kondenswasser nicht das Sensorelement beaufschlagen kann, sondern im keramischen Fasermaterial zurückgehalten wird und verdampft.If the ceramic fiber material is further arranged so that at least the majority of the measuring gas can only flow through the ceramic fiber material to the sensor element, there is the further advantage that condensed water carried in the measuring gas cannot act on the sensor element, but is retained in the ceramic fiber material and evaporated.
Durch die in den Unteranspruchen aufgeführten Maßnahmen sind vorteilhafte Weiterbildungen des im Hauptanspruch angegebenen Gassensors möglich.The measures listed in the subclaims allow advantageous developments of the gas sensor specified in the main claim.
Eine besonders sichere beabstandete Fixierung des Fasermaterials ist durch ein doppelwandiges Schutzrohr erreichbar .A particularly secure, spaced fixing of the fiber material can be achieved by means of a double-walled protective tube.
Zeichnungdrawing
Zwei Ausfuhrungsbeispiele sind in der Zeichnung dargestellt und in der nachfolgenden Beschreibung naher erläutert. Es zeigen Figur 1 als erstes Ausfuhrungsbeispiel und Figur 2 als weiteres Ausfuhrungsbeispiel den Meßbereich eines Gassensors in Schnittdarstellung. Die Figuren 1 und 2 zeigen als Ausfuhrungsbeispiel der vorliegenden Erfindung den Meßbereich einen Gassensors 10, der ein in einem Meßgasraum 23 befindliches Sensorelement 20, ein doppelwandiges Schutzrohr 22 mit Zu- und Ausströmöffnungen 24 sowie ein keramisches Fasermaterial 21 aufweist. Die in Figur 1 und 2 dargestellten Ausfuhrungsbeispiele unterscheiden sich in der Ausfuhrung des doppelwandigen Schutzrohres 22. In dem in Figur 1 dargestellten Ausfuhrungsbeispiel sind die Zu- und Ausströmöffnungen 24 so angeordnet, daß das Meßgas senkrecht zur Achse des Sensorelements in den Meßgasraum 23 eindringt, wahrend in dem in Figur 2 dargestellten Ausfuhrungsbeispiel das Meßgas auch parallel zur Achse des Sensorelements 20 in den Meßgasraum 23 eindringt. In beiden Ausfuhrungsbeispielen ist das keramische Fasermaterial 21 derart zwischen den beiden Wanden des doppelwandigen Schutzrohres 22 angeordnet, daß das Meßgas den Meßgasraum 23 nur nach Durchfluß durch das keramische Fasermaterial 21 erreicht. Das keramischeTwo exemplary embodiments are shown in the drawing and explained in more detail in the following description. 1 shows as a first exemplary embodiment and FIG. 2 as a further exemplary embodiment shows the measuring range of a gas sensor in a sectional view. 1 and 2 show, as an exemplary embodiment of the present invention, the measuring range of a gas sensor 10 which has a sensor element 20 located in a measuring gas space 23, a double-walled protective tube 22 with inflow and outflow openings 24 and a ceramic fiber material 21. The exemplary embodiments shown in FIGS. 1 and 2 differ in the design of the double-walled protective tube 22. In the exemplary embodiment shown in FIG. 1, the inflow and outflow openings 24 are arranged such that the measuring gas penetrates into the measuring gas space 23 perpendicular to the axis of the sensor element, while in the exemplary embodiment shown in FIG. 2, the measuring gas also penetrates into the measuring gas space 23 parallel to the axis of the sensor element 20. In both exemplary embodiments, the ceramic fiber material 21 is arranged between the two walls of the double-walled protective tube 22 in such a way that the measuring gas only reaches the measuring gas space 23 after it has flowed through the ceramic fiber material 21. The ceramic
Fasermaterial 21 kann beispielsweise als Watte, Wolle oder Flies eingesetzt werden. Das keramische Fasermaterial 21 kann in den Innenraum des doppelwandigen Schutzrohres 22 außerdem durch Einlegen von gestanzten Keramikfaserscheiben oder durch Wicklung von Keramikfaserband eingebracht werden.Fiber material 21 can be used, for example, as cotton wool, wool or fleece. The ceramic fiber material 21 can also be introduced into the interior of the double-walled protective tube 22 by inserting punched ceramic fiber discs or by winding ceramic fiber tape.
In bevorzugter Ausfuhrung weist das keramische Fasermaterial 21 Fasern aus A1203 und/oder Zr0 auf. Die keramischen Fasern haben in bevorzugter Ausfuhrung eine Dicke von 2 bis 5 μm. Die Lange der Einzelfasern des keramischen Fasermaterials ist in bevorzugter Ausfuhrung großer oder gleich 1 mm.In a preferred embodiment, the ceramic fiber material 21 has fibers made of A1 2 0 3 and / or Zr0. In a preferred embodiment, the ceramic fibers have a thickness of 2 to 5 μm. In a preferred embodiment, the length of the individual fibers of the ceramic fiber material is greater than or equal to 1 mm.
Es ist für den Fachmann ohne weiteres möglich, dieIt is readily possible for a person skilled in the art to
Beabstandung des keramischen Fasermaterials 21 vom Sensorelement 20 auch auf andere Weise zu verwirklichen. So kann das keramische Fasermaterial 21 beispielsweise durch ein in den Meßgasraum 23 eingebrachtes Drahtgitter von dem Sensorelement 20 beabstandet gehalten werden. The ceramic fiber material 21 can also be spaced apart from the sensor element 20 in another way. So For example, the ceramic fiber material 21 can be kept at a distance from the sensor element 20 by means of a wire mesh introduced into the measuring gas space 23.

Claims

Ansprüche Expectations
1. Elektrochemischer Meßfühler zur Bestimmung von Gaskomponenten und/oder Gaskonzentrationen in Gasgemischen mit einem Sensorelement, das von einem Schutzrohr umgeben ist, das den Zutritt eines Meßgases zum Sensorelement erlaubt, wobei sich im Schutzrohr ein keramisches Fasermaterial befindet, dadurch gekennzeichnet, daß das keramische Fasermaterial (21) beabstandet vom Sensorelement (20) im Schutzrohr (22) angeordnet ist.1. Electrochemical sensor for determining gas components and / or gas concentrations in gas mixtures with a sensor element which is surrounded by a protective tube that allows access of a measuring gas to the sensor element, wherein a ceramic fiber material is located in the protective tube, characterized in that the ceramic fiber material (21) is arranged at a distance from the sensor element (20) in the protective tube (22).
2. Meßfühler nach Anspruch 1, dadurch gekennzeichnet, daß das Schutzrohr (22) zumindest bereichsweise doppelwandig ausgeführt ist und daß das keramische Fasermaterial (21) zumindest im Bereich von Zu- und Ausstromöffnungen (24) zwischen den beiden Wanden des Schutzrohres (22) angeordnet ist.2. Sensor according to claim 1, characterized in that the protective tube (22) is at least partially double-walled and that the ceramic fiber material (21) is arranged at least in the area of inflow and outflow openings (24) between the two walls of the protective tube (22) is.
3. Meßfühler nach Anspruch 2, dadurch gekennzeichnet, daß im Bereich der Zu- und Ausströmöffnungen (24) das Schutzrohr doppelwandig ausgebildet ist. 3. Sensor according to claim 2, characterized in that in the region of the inflow and outflow openings (24) the protective tube is double-walled.
4. Meßfühler nach Anspruch 1, dadurch gekennzeichnet, daß das keramische Fasermaterial (21) Fasern aus Al203 und/oder Zr02 aufweist.4. Sensor according to claim 1, characterized in that the ceramic fiber material (21) has fibers made of Al 2 0 3 and / or Zr0 2 .
5. Meßfühler nach Anspruch 1, dadurch gekennzeichnet, daß die keramischen Fasern eine Dicke von 2 bis 5 um haben.5. Sensor according to claim 1, characterized in that the ceramic fibers have a thickness of 2 to 5 µm.
6. Meßfühler nach Anspruch 1, dadurch gekennzeichnet, daß die keramischen Fasern eine Lange von großer oder gleich 1 mm aufweisen. 6. Sensor according to claim 1, characterized in that the ceramic fibers have a length of greater than or equal to 1 mm.
PCT/DE2001/000079 2000-03-10 2001-01-11 Electrochemical detecting element WO2001067082A1 (en)

Applications Claiming Priority (2)

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DE20004514U DE20004514U1 (en) 2000-03-10 2000-03-10 Electrochemical sensor
DE20004514.8 2000-03-10

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2005121763A1 (en) * 2004-06-05 2005-12-22 Robert Bosch Gmbh Sensor for determining the oxygen concentration in internal combustion engines
US7537383B2 (en) 2004-11-05 2009-05-26 Emitec Gesellschaft Fuer Emissionstechnologie Mbh Protective element for a measuring probe and corresponding measuring probe, honeycomb body and motor vehicle
EP2554984A1 (en) * 2011-08-03 2013-02-06 Robert Bosch Gmbh Gas sensor with thermal shock protection
WO2014099753A1 (en) * 2012-12-20 2014-06-26 Robert Bosch Gmbh Gas sensor with thermal shock protection

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102004015783A1 (en) * 2004-03-17 2005-10-06 Robert Bosch Gmbh Sensor for determining the oxygen concentration in the exhaust gas of internal combustion engines
DE102006060312A1 (en) * 2006-12-20 2008-06-26 Robert Bosch Gmbh gas sensor
DE102007016976B4 (en) * 2007-04-10 2021-07-29 Bayerische Motoren Werke Aktiengesellschaft Protective cap for a gas sensor and gas sensor
DE102008000463A1 (en) 2008-02-29 2009-09-03 Robert Bosch Gmbh exhaust gas sensor
DE102013204943A1 (en) * 2013-03-20 2014-09-25 Continental Automotive Gmbh Sensor for detecting a gas content
DE102013221260A1 (en) 2013-10-21 2015-04-23 Robert Bosch Gmbh Sensor device for detecting at least one property of a fluid medium
DE102013221270A1 (en) 2013-10-21 2015-04-23 Robert Bosch Gmbh Sensor device for detecting at least one property of a fluid medium
DE102013221262A1 (en) 2013-10-21 2015-04-23 Robert Bosch Gmbh Sensor device for detecting at least one property of a fluid medium

Citations (3)

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Publication number Priority date Publication date Assignee Title
US4712419A (en) * 1985-05-13 1987-12-15 Toyota Jidosha Kabushiki Kaisha Air/fuel ratio detector
US4830727A (en) * 1987-05-19 1989-05-16 Osaka Sanso Kogyo Ltd. Composite probe for measuring the concentration of an impurity element in molten iron
US5762771A (en) * 1996-02-06 1998-06-09 Denso Corporation Air-fuel ratio sensor

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4712419A (en) * 1985-05-13 1987-12-15 Toyota Jidosha Kabushiki Kaisha Air/fuel ratio detector
US4830727A (en) * 1987-05-19 1989-05-16 Osaka Sanso Kogyo Ltd. Composite probe for measuring the concentration of an impurity element in molten iron
US5762771A (en) * 1996-02-06 1998-06-09 Denso Corporation Air-fuel ratio sensor

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2005121763A1 (en) * 2004-06-05 2005-12-22 Robert Bosch Gmbh Sensor for determining the oxygen concentration in internal combustion engines
US7537383B2 (en) 2004-11-05 2009-05-26 Emitec Gesellschaft Fuer Emissionstechnologie Mbh Protective element for a measuring probe and corresponding measuring probe, honeycomb body and motor vehicle
EP2554984A1 (en) * 2011-08-03 2013-02-06 Robert Bosch Gmbh Gas sensor with thermal shock protection
WO2014099753A1 (en) * 2012-12-20 2014-06-26 Robert Bosch Gmbh Gas sensor with thermal shock protection
US9297791B2 (en) 2012-12-20 2016-03-29 Robert Bosch Gmbh Gas sensor with thermal shock protection

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Publication number Publication date
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