DE2908368A1 - MEASURING PROBE FOR DETERMINING THE OXYGEN PARTIAL PRESSURE IN MELTS - Google Patents
MEASURING PROBE FOR DETERMINING THE OXYGEN PARTIAL PRESSURE IN MELTSInfo
- Publication number
- DE2908368A1 DE2908368A1 DE19792908368 DE2908368A DE2908368A1 DE 2908368 A1 DE2908368 A1 DE 2908368A1 DE 19792908368 DE19792908368 DE 19792908368 DE 2908368 A DE2908368 A DE 2908368A DE 2908368 A1 DE2908368 A1 DE 2908368A1
- Authority
- DE
- Germany
- Prior art keywords
- tube
- tablet
- solid electrolyte
- melt
- solid
- 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.)
- Granted
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
- G01N27/403—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
- G01N27/4073—Composition or fabrication of the solid electrolyte
-
- 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
- G01N27/4071—Cells and probes with solid electrolytes for investigating or analysing gases using sensor elements of laminated structure
Description
Meßfühler zur Bestimmung des Sauerstoff-Partialdruckes in Sensor for determining the partial pressure of oxygen in
heißen Flüssigkeiten, insbesondere Schmelzen Die Erfindung betrifft eine neuartige Meßsonde, mit welcher der Sauerstoff-Partialdruck in heißen Schmelzen, wie z.B, solchen aus Glas, Metallen o.ä. einfach und zuverlässig bestimmt werden kann. hot liquids, especially melts The invention relates to a new type of measuring probe, with which the oxygen partial pressure in hot melts, such as those made of glass, metals or the like can be easily and reliably determined can.
Die Kenntnis des Sauerstoff-Partialdruckes (pg ) in Schmelzen ist aus vielen Gründen von großer technischer edeutung, beispielsweise beim Läutern oder bei der Einstellung der Farbe in Gläsern.The knowledge of the partial pressure of oxygen (pg) in melts is of great technical importance for many reasons, for example for lautering or when setting the color in glasses.
Man hat bereits versucht, zur Durchführung derartiger Messungen Festkörperelektrolytsonden, die nach elektrochemischem Prinzip arbeiten, einzusetzen. Derartige Sonden bestehen im Prinzip aus einem einseitig verschlossenen Rohr aus- einem Festkörperelektrolyten, wie z.B. Zirkondioxid, in einer Festkörper-Meßkette, deren eine Halbzelle die Schmelze darstellt, die zu untersuchen ist (s. z.B. DE-OS 2 001 012).Attempts have already been made to use solid-state electrolyte probes to carry out such measurements, that work on the electrochemical principle. Such probes exist in principle from a tube closed on one side made of a solid electrolyte, how e.g. zirconium dioxide, in a solid-state electrode, one half-cell of which is the melt which is to be examined (see e.g. DE-OS 2 001 012).
Bisher ist jedoch nur im Labormeßstab gelungen, dieses Meßsystem auf z.B. Glasschmelzen zu übertragen. Einer Anwendung dieser bekannten, aus einseitig geschlqssenen Festkörperelektrolytrohren bestehenden Meßsonden in der aktuellen Glasproduktion standen bisher folgende Nachteile entgegen: - schlechte Temperaturwechselbeständigkeit, - schlechte mechanische Stabilität, - Bildung einer Spülkante an der Dreiphasengrenze "Luft-Glas-Sonde", - korrosiver Angriff der Glasschmelze und damit- verbundene unerwünschte Korrosionsprodukte im Glas, - kurze Standzeit, - hoher Preis.So far, however, this measuring system has only been successful in the laboratory measuring stick e.g. to transfer molten glass. An application of this well-known, from one-sided closed solid electrolyte tubes existing measuring probes in the current The following disadvantages have prevented glass production so far: - poor thermal shock resistance, - poor mechanical stability, - formation of a flushing edge at the three-phase boundary "Air-glass probe" - corrosive attack on the glass melt and associated undesirable effects Corrosion products in the glass, - short service life, - high price.
Ziel der vorliegenden Erfindung ist eine Meßsonde, welche die vorstehend geschilderten Nachteile nicht aufweist.The object of the present invention is a measuring probe, which the above does not have the disadvantages described.
Dieses Ziel wird mit einer Meßsonde gemäß den Patentansprüchen erreicht.This aim is achieved with a measuring probe according to the claims.
Das Meßprinzip beruht auf der Fähigkeit einiger keramischer Materialien (z.B. stabilisiertes ZrO2 oder ThO2)O²-Ionen bei erhöhten Temperaturen zu leiten. Befinden sich nämlich auf beiden Seiten eines festen Ionenleiters verschiedene 02-Partialdrücke (z.B. PO (1) in einem Referenzgas, PO 2) in einer Glasschmelze) so entsteht nach Nernst eine elektromotorische Kraft EMK der Größe: RT EMK = zF ln(P02 (1)/P02 (2)) (z = Wertigkeitswechsel; hier = 4);F = Faradaykonst.; R = Gaskonst.; T = abs. Temp.).The measuring principle is based on the ability of some ceramic materials (e.g. stabilized ZrO2 or ThO2) to conduct O² ions at elevated temperatures. If there are different O2 partial pressures on both sides of a solid ionic conductor (e.g. PO (1) in a reference gas, PO 2) in a glass melt) so arises after Nernst an electromotive force EMK of the size: RT EMK = zF ln (P02 (1) / P02 (2)) (e.g. = Change in value; here = 4); F = Faraday const .; R = gas const.; T = abs. Temp.).
Die EMK wird mittels eines hochohmigen Volmeters zwischen zwei Elektroden auf beiden Seiten des Festkörperelektrolyten gemessen.The EMF is generated by means of a high-resistance voltmeter between two electrodes measured on both sides of the solid electrolyte.
Die Elektroden bestehen in der Regel aus Platin. Dabei wird die Elektrode auf der Referenzseite über eine poröse Pt-Schicht auf der Festkörperelektrolyt-Oberfläche kontaktiert. Die andere Elektrode wird lediglich in die Glasschmelze eingetaucht. Dabei sorgt die Schmelze zwischen Festkörperelektrolyt und Elektrode für elektrischen Kontakt.The electrodes are usually made of platinum. In doing so, the electrode on the reference side via a porous Pt layer on the solid electrolyte surface contacted. The other electrode is simply immersed in the glass melt. The melt between the solid electrolyte and the electrode provides electrical energy Contact.
In Figur 1 ist der prinzipielle Aufbau der erfindungsgemäßen Meßvorrichtung schematisch dargestellt. Es stellen dar: 1 - EMK-Meßgerät 2 - Referenzgas 3 - Metallrohr (z.B. Pt/Rh) 4 - Pt-Innenelektrode 5 - Pt-Elektrodenkontakt 6 - Festelektrolyt (z.B. ZrO2 (CaO)) 7 - Rohrbodenbördelung 8 - Glasschmelze 9 - Pt-Außenelektrode Die in Figur 1 dargestellte Meßkette sieht demnach folgendermaßen aus.In Figure 1 is the basic structure of the measuring device according to the invention shown schematically. It shows: 1 - EMF measuring device 2 - Reference gas 3 - Metal pipe (e.g. Pt / Rh) 4 - Pt inner electrode 5 - Pt electrode contact 6 - solid electrolyte (e.g. ZrO2 (CaO)) 7 - Tube sheet flange 8 - Glass melt 9 - Pt outer electrode The in The measuring chain shown in FIG. 1 therefore looks as follows.
Pt, 02(pro )/ZrO2(CaO)//Schmelze, 02(P ,xVPt.Pt, 02 (pro) / ZrO2 (CaO) // melt, 02 (P, xVPt.
2 02 Die erfindungsgemäße Vorrichtung wird hergestellt, indem eine Tablette aus einem sauerstoffionenleitenden Festkörperelektrolyten in ein Metallrohr derart eingesetzt wird, daß diese Tablette das untere Ende dieses Metallrohres temperaturbeständig und gasdicht abschließt. 2 02 The device according to the invention is produced by a Tablet made from a solid electrolyte that conducts oxygen ions in a metal tube is used in such a way that this tablet is temperature-resistant to the lower end of this metal tube and seals in a gastight manner.
Das Metallrohr kann aus einem Edelmetall (z.B. Platin oder Platin/Rhodium) oder z.B. aus Edelstahl bestehen.The metal tube can be made of a precious metal (e.g. platinum or platinum / rhodium) or made of stainless steel, for example.
Gemäß einer bevorzugten Ausführungsform der Erfindung wird die Festkörperelektrolyttablette durch Heißpressen auf den durchbohrten Boden des Metallrohres aufgesintert, wobei Sinterdruck und -temperatur einander angepaßt werden können. Der Festkörperelektrolyt ist ein sauerstoffionenleitendes Oxid, wie z.B. ZrO2, Th02, HfO2 oder LaO2, der gegebenenfalls mit z.B Zr0 2 einem niedrigerwertigen Oxid, wie CaO, MgO, y203 oder Sc203 dotiert ist.According to a preferred embodiment of the invention, the solid electrolyte tablet sintered by hot pressing onto the drilled bottom of the metal tube, wherein Sintering pressure and temperature can be adapted to one another. The solid electrolyte is an oxide that conducts oxygen ions, such as ZrO2, Th02, HfO2 or LaO2, which optionally with e.g. Zr0 2 a lower value oxide such as CaO, MgO, y203 or Sc203 is doped.
Vorzugsweise wird die Bezugselektrode über eine poröse Pt-Schicht auf der Oberfläche der Tablette kontaktiert, Dabei kann der Pt-Draht auf die Schicht aufgesintert oder einfach nur aufgedrückt (Druckkontakt) werden. Eine dritte Möglichkeit besteht darin, in der Tablette eine Vertiefung anzubringen und in ihr die Elektrode, die an dieser Stelle zum besseren Kontakt etwas aufgewickelt sein kann, mit Hilfe eines Pulvers bei maximal 15000C einzusintern.The reference electrode is preferably over a porous Pt layer contacted on the surface of the tablet, the Pt wire can be attached to the layer sintered on or simply pressed on (pressure contact). A third possibility consists in making a recess in the tablet and in it the electrode, which can be wound up a bit at this point for better contact, with help sintering a powder at a maximum of 15000C.
Vorzugsweise wird die Referenzelektrode durch ein .Ein-bzw. Mehrkapillarenrohr aus einem isolierendem Feuerfest-Material (z.B. Al203) vor elektrischem Kontakt zum metallischen Außenrohr geschützt. Mit seiner Hilfe kann auch ein Thermoelement zur Messung der Temperatur bis an den Festelektrolyten herangeführt, Referenzgas durchgeleitet und schließlich bei Druckkontakt der Druck der Bezugselektrode1 die um das untere Ende des Kapillarenrohres gebogen ist, auf die Metallisierungsfläche aufgebracht werden.The reference electrode is preferably connected by a .ein or. Multi-capillary tube made of an insulating refractory material (e.g. Al203) in front of electrical contact protected from the metallic outer tube. With its help, a thermocouple can also be used to measure the temperature brought up to the solid electrolyte, reference gas and finally the pressure of the reference electrode1 on contact with pressure is bent around the lower end of the capillary tube, onto the metallization surface be applied.
Da an der Unterseite der Tablette Blasen eingefangen werden können, die aus der Schmelze aufsteigen, kann gemäß einer anderen Ausführungsform diese Tablette von außen am Boden des Metallrohres befestigt werden. Ganz besonders vorteilhaft ist es, dieser Tablette eine abgerundete Gestalt, z.B. Halbkugelform zu geben.Since bubbles can be trapped at the bottom of the tablet, which rise from the melt can, according to another embodiment, this Tablet from the outside at the bottom of the metal tube be attached. It is particularly advantageous to give this tablet a rounded shape, e.g. To give hemispherical shape.
In Figur 2 ist als Beispiel der "EMK-Zeit-Verlauf" einer "ZrO2(Y203)-Pt/Rh-Sonde" in einer Na2B407-Schmelze bei 9000C und verschiedenen Atmosphären dargestellt. In dieser Darstellung bedeuten: L = Luft (P02 = 0.21 atm) 02 = Sauerstoff (P02 = 1 atm) L/O2(r) = Luft über der Glasschmelze und O2 als Bezugsgas L/L(r) = Luft über der Glasschmelze und Luft als Bezugsgas 02/L(r) = °2 über der Glasschmelze und Luft als Bezugsgas O2/O2(r) = O2 auf beiden Seiten - = Theoretische EMK für O2/L(r) bei 900°C -------- = Theoretische EMK für P02 (Bezugsgas) = P02 (Glas); also L/L(r) oder O2/O2(r) ......... = Theoretische EMK für L/02(r)As an example, FIG. 2 shows the "EMF time curve" of a "ZrO2 (Y203) -Pt / Rh probe" shown in a Na2B407 melt at 900C and different atmospheres. In in this representation: L = air (P02 = 0.21 atm) 02 = oxygen (P02 = 1 atm) L / O2 (r) = air above the glass melt and O2 as reference gas L / L (r) = air above the glass melt and air as reference gas 02 / L (r) = ° 2 above the glass melt and air as reference gas O2 / O2 (r) = O2 on both sides - = Theoretical EMF for O2 / L (r) at 900 ° C -------- = Theoretical EMF for P02 (reference gas) = P02 (glass); so L / L (r) or O2 / O2 (r) ......... = Theoretical EMF for L / 02 (r)
Claims (10)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE19792908368 DE2908368C2 (en) | 1979-03-03 | 1979-03-03 | Measuring probe for determining the partial pressure of oxygen in hot media |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE19792908368 DE2908368C2 (en) | 1979-03-03 | 1979-03-03 | Measuring probe for determining the partial pressure of oxygen in hot media |
Publications (2)
Publication Number | Publication Date |
---|---|
DE2908368A1 true DE2908368A1 (en) | 1980-09-04 |
DE2908368C2 DE2908368C2 (en) | 1985-05-09 |
Family
ID=6064412
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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DE19792908368 Expired DE2908368C2 (en) | 1979-03-03 | 1979-03-03 | Measuring probe for determining the partial pressure of oxygen in hot media |
Country Status (1)
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DE (1) | DE2908368C2 (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE3109454A1 (en) * | 1981-03-12 | 1982-09-23 | Schott Glaswerke | Probe for measuring oxygen partial pressures in highly aggressive media |
DE4138409A1 (en) * | 1991-11-22 | 1993-05-27 | Schott Glaswerke | Reference electrode for partial pressure measurements in high temperature medium - has protective ceramic sleeve enclosing solid electrolyte probe of small size with external connection head to eliminate water cooling |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3752753A (en) * | 1971-04-30 | 1973-08-14 | G Fitterer | Method of fabricating a sensor for the determination of the oxygen content of liquid metals |
US3768259A (en) * | 1971-07-06 | 1973-10-30 | Universal Oil Prod Co | Control for an engine system |
DE2357117A1 (en) * | 1972-11-15 | 1974-05-30 | Us Atomic Energy Commission Wa | DEVICE FOR MEASURING THE OXYGEN ACTIVITY IN LIQUID SODIUM |
DE2754522A1 (en) * | 1976-12-07 | 1978-06-08 | Commw Scient Ind Res Org | SOLID MIXED ELECTROLYTE MATERIAL AS WELL AS OXYGEN SENSORS THEREOF AND PROCESS FOR THE PRODUCTION OF IT |
-
1979
- 1979-03-03 DE DE19792908368 patent/DE2908368C2/en not_active Expired
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3752753A (en) * | 1971-04-30 | 1973-08-14 | G Fitterer | Method of fabricating a sensor for the determination of the oxygen content of liquid metals |
US3768259A (en) * | 1971-07-06 | 1973-10-30 | Universal Oil Prod Co | Control for an engine system |
DE2357117A1 (en) * | 1972-11-15 | 1974-05-30 | Us Atomic Energy Commission Wa | DEVICE FOR MEASURING THE OXYGEN ACTIVITY IN LIQUID SODIUM |
DE2754522A1 (en) * | 1976-12-07 | 1978-06-08 | Commw Scient Ind Res Org | SOLID MIXED ELECTROLYTE MATERIAL AS WELL AS OXYGEN SENSORS THEREOF AND PROCESS FOR THE PRODUCTION OF IT |
Non-Patent Citations (1)
Title |
---|
RÖMPP Chemie Lexikon, 7. Aufl., Bd. 5, 1975, Stickwort "Sintern" * |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE3109454A1 (en) * | 1981-03-12 | 1982-09-23 | Schott Glaswerke | Probe for measuring oxygen partial pressures in highly aggressive media |
DE4138409A1 (en) * | 1991-11-22 | 1993-05-27 | Schott Glaswerke | Reference electrode for partial pressure measurements in high temperature medium - has protective ceramic sleeve enclosing solid electrolyte probe of small size with external connection head to eliminate water cooling |
Also Published As
Publication number | Publication date |
---|---|
DE2908368C2 (en) | 1985-05-09 |
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Legal Events
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OAP | Request for examination filed | ||
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8127 | New person/name/address of the applicant |
Owner name: SCHOTT GLASWERKE, 6500 MAINZ, DE |
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8181 | Inventor (new situation) |
Free format text: FREY, THOMAS, DIPL.-ING. DR., 8520 ERLANGEN, DE BAUCKE, FRIEDRICK G.K., DIPL.-CHEM. DR., 6500 MAINZ, DE SCHAEFFER, HELMUT A., DR., 8520 ERLANGEN, DE |
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D2 | Grant after examination | ||
8364 | No opposition during term of opposition | ||
8339 | Ceased/non-payment of the annual fee |