EP2286196A1 - Enveloppe de protection pour détecteurs en fonte d'aluminium - Google Patents

Enveloppe de protection pour détecteurs en fonte d'aluminium

Info

Publication number
EP2286196A1
EP2286196A1 EP09761395A EP09761395A EP2286196A1 EP 2286196 A1 EP2286196 A1 EP 2286196A1 EP 09761395 A EP09761395 A EP 09761395A EP 09761395 A EP09761395 A EP 09761395A EP 2286196 A1 EP2286196 A1 EP 2286196A1
Authority
EP
European Patent Office
Prior art keywords
measuring device
wettable
aluminum
protective cover
aluminum material
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Withdrawn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
EP09761395A
Other languages
German (de)
English (en)
Inventor
Paul Verstreken
Jozef Theodoor Aegten
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.)
Heraeus Electro Nite International NV
Original Assignee
Heraeus Electro Nite International NV
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 Heraeus Electro Nite International NV filed Critical Heraeus Electro Nite International NV
Publication of EP2286196A1 publication Critical patent/EP2286196A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
    • G01K1/00—Details of thermometers not specially adapted for particular types of thermometer
    • G01K1/08—Protective devices, e.g. casings
    • G01K1/10—Protective devices, e.g. casings for preventing chemical attack
    • G01K1/105—Protective devices, e.g. casings for preventing chemical attack for siderurgical use
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
    • G01K1/00—Details of thermometers not specially adapted for particular types of thermometer
    • G01K1/08—Protective devices, e.g. casings
    • G01K1/12—Protective devices, e.g. casings for preventing damage due to heat overloading
    • G01K1/125—Protective devices, e.g. casings for preventing damage due to heat overloading for siderurgical use

Definitions

  • the invention relates to a measuring device with a protective cover and a sensor arranged in the protective cover.
  • such measuring devices are e.g. from JP 57-101730 or from US 4,124,465. These measuring devices are used for temperature measurements in aluminum melts or cryolite melts.
  • measurements in such or in other aggressive high-temperature melts have the problem that the sensor itself can be attacked by the aggressive melt and, on the other hand, must be adequately protected.
  • such protection is important in measuring devices that are used for long-term measurement. In such measuring devices, on the one hand, it must be ensured that the sensor itself reaches sufficient contact with the melt to be measured, but that, on the other hand, it is also sufficiently protected.
  • thermocouples For temperature sensors such as thermocouples, for example, this means that a good thermal contact between the sensor and the melt must be ensured with simultaneous protection against chemical corrosion, electrochemical corrosion and mechanical damage caused by thermal shocks when immersing the measuring device in the melt.
  • Sensors intended for use in molten aluminum or cryolite melts must be protected against electrochemical corrosion otherwise generated by the electric field in the bath.
  • cryolite is a chemically relatively aggressive material.
  • the aluminum melt has a strong reducing effect, so that the measuring device must be protected against reduction. At the same time protection against oxidation is necessary because, for example, the usually present carbon dioxide favors oxidation of the measuring device.
  • coatings of the known materials do not adequately protect a sensor, in particular a temperature sensor, in order to enable measurement over a longer period of time, so that the measuring device can be used reliably beyond a one-time temperature measurement.
  • the present invention has for its object to improve the known measuring devices, in particular those for use in salt, cryolite or aluminum melts, so that a longer use is possible.
  • the object is achieved with a measuring device with the features of the independent claims.
  • Advantageous embodiments are specified in the subclaims.
  • the protective cover is formed multi-layer, wherein it has a closed on one side support tube made of metal, in which the sensor is arranged and on the outer surface of a coating of a non-wettable by aluminum material is disposed, wherein on this coating, a further layer of an aluminum-wettable material is applied.
  • the life of the protective cover is significantly increased, it is achieved a lifetime of more than 24 h.
  • liquid aluminum is very aggressive. This can not penetrate the non-wettable layer, so that the support tube is protected with the sensor disposed therein.
  • the wettable layer has the effect, when the measuring device is used for the measurement in aluminum melts, that the protective cover is coated with a light aluminum layer as it passes through the cryolite layer resting on the aluminum melt, so that cryolite can not adhere to the measuring device.
  • the protective cover is sealed to the outside to protect against oxidation and cracking by mechanical stresses and against chemical corrosion and electrochemical corrosion.
  • This is the support tube with the sensor arranged therein, which in particular a temperature sensor, as bei- For example, a thermocouple may be protected by the liquid aluminum against almost all harmful influences, except against the reactivity of the
  • the aluminum coating which is not wetted by the aluminum, serves as protection against the aluminum on the support tube.
  • the wettable layer is therefore soaked in liquid aluminum, which remains in this layer and can not penetrate into the underlying layer, so that the aluminum also does not come into contact with the support tube.
  • the (ideally perfect) wettability of the layer arranged on the non-wettable layer causes the aluminum layer to be renewed virtually continuously.
  • Both coatings can be applied by means of spray methods, for example by plasma spraying.
  • an adhesion promoter layer can be arranged below the non-wettable layer.
  • the primer layer may be of any suitable commercially available material, for example, NiCrAlY. This layer can provide additional protection of the carrier tube against oxidation in the atmosphere.
  • the support tube is formed of titanium or martensitic or ferritic stainless steel.
  • the non-wettable material is essentially formed of one or more oxides, preferably alumina or magnesia or a mixture thereof.
  • the material which is not wettable by aluminum is preferably not an ion conductor, that is to say an insulator or electron conductor, in order to protect the support tube also electrically against the aluminum-wettable coating and against electrochemical effects.
  • the aluminum-wettable material is formed essentially of at least one transition-metal boride, it being possible for preference to use one or more borides from the group consisting of TiB 2 , ZrB 2 and HfB 2 .
  • the aluminum-wettable material is coated on its outer surface with a metal, which metal may be useful aluminum.
  • the outer aluminum layer necessary for measurements in aluminum melts is already present when the measuring device is immersed and does not first have to be formed in the melt itself. This layer liquefies when immersed in the molten aluminum bath or already during passage through the cryolite layer, fills possibly existing microcracks or porosities in the aluminum-wettable layer and thus forms the protective layer described above.
  • the aluminum layer can also be applied by spraying.
  • the individual coatings are preferably each about 50 to 1000 microns thick.
  • the aluminum layer regenerates virtually continuously on the wettable layer, since this wettable layer, when formed of borides, is itself an electron conductor and makes electrical contact to the molten aluminum, the cathode in the electrochemical cell. As a result, the wettable layer itself becomes the cathode, so that aluminum is constantly deposited on it electrochemically. This process can be enhanced when the boride coating is bonded to the cathode present in electrolyzers.
  • the protective cover preferably the interior of the support tube, is connected to a source of cooling gas.
  • the cooling gas source may be a gas bottle.
  • air or an inert gas can be used as the cooling gas.
  • the gas cooling By the gas cooling, a melting edge is formed / frozen on the protective tube around the protective tube at the interface between ambient gas and Cryolithschelze, which avoids the corrosion at this point.
  • a melting device in particular for the production of aluminum, with a melting tank having at least one bus bar and a measuring device according to one of claims 1 to 13, characterized in that the wettable by aluminum material of the measuring device via a connecting cable with at least one busbar electrically is conductively connected.
  • This electrically conductive compound promotes the electrochemical formation of aluminum on the aluminum wettable material
  • Fig. 1 is a melting tank for aluminum production, schematically
  • Fig. 2 is a sensor protective cover in section
  • Fig. 3 shows another melting tank.
  • a cryolite layer 3 is arranged on the liquid aluminum 2, into which the anodes 4 protrude.
  • the busbars 5 are arranged in the bottom of the melting tank 1.
  • the melting tank 1 forms with the busbars 5 and the aluminum 2, the cathode.
  • the measuring device is formed by a thermocouple arranged in a protective sheath 6 which is connected to a measuring instrument 8 via a cable 7.
  • the protective sheath 6 of the thermocouple is immersed in the aluminum layer 2 through the cryolite layer 3, so that it must withstand the influence of both materials.
  • the temperature of the melt is optimally between 950 and 970 0 C, but can also drop to 930 0 C or rise up to 1000 0 C.
  • the wettable Layer 12 may be connected via a connecting cable 14 to the busbar 5.
  • the interior of the protective cover 6 is connected via a gas line 15 with a cooling gas cylinder 16.
  • the protective cover for the sensor shown in Fig. 2 comprises an inner metal tube 9 made of ferritic or martensitic stainless steel or titanium.
  • the metal tube 9 has a diameter of about 14 mm and a wall thickness of about 3 mm.
  • the adhesion promoter layer 10 of NiCrAlY arranged on the outer surface of the metal tube 9 closed at one end has a thickness of approximately 80 ⁇ m.
  • the non-wettable layer 11 is arranged on the adhesion promoter layer 10.
  • This is preferably formed of aluminum oxide and has a thickness of about 150 microns.
  • the wettable layer 12 disposed thereon is formed of TiB 2 and has a thickness of about 250 ⁇ m.
  • an outer aluminum layer 13 is arranged with a thickness of about 500 microns.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Measuring Temperature Or Quantity Of Heat (AREA)
  • Electrolytic Production Of Metals (AREA)

Abstract

L'invention concerne un dispositif de mesure qui présente une enveloppe de protection et un détecteur disposé dans l'enveloppe de protection, et est caractérisée en ce que l'enveloppe de protection présente un tube de support en métal, fermé d'un côté, à la surface extérieure duquel est disposé un revêtement en un matériau qui ne peut être mouillé par l'aluminium, et en ce que sur ce revêtement est appliquée une autre couche en un matériau qui peut être mouillé par l'aluminium.
EP09761395A 2008-06-10 2009-05-28 Enveloppe de protection pour détecteurs en fonte d'aluminium Withdrawn EP2286196A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102008027505A DE102008027505A1 (de) 2008-06-10 2008-06-10 Messeinrichtung
PCT/EP2009/003792 WO2009149832A1 (fr) 2008-06-10 2009-05-28 Enveloppe de protection pour détecteurs en fonte d'aluminium

Publications (1)

Publication Number Publication Date
EP2286196A1 true EP2286196A1 (fr) 2011-02-23

Family

ID=41037799

Family Applications (1)

Application Number Title Priority Date Filing Date
EP09761395A Withdrawn EP2286196A1 (fr) 2008-06-10 2009-05-28 Enveloppe de protection pour détecteurs en fonte d'aluminium

Country Status (10)

Country Link
US (1) US8425112B2 (fr)
EP (1) EP2286196A1 (fr)
CN (1) CN102057262A (fr)
AU (1) AU2009256994B2 (fr)
BR (1) BRPI0915048A2 (fr)
CA (1) CA2723943A1 (fr)
DE (1) DE102008027505A1 (fr)
RU (1) RU2010153997A (fr)
WO (1) WO2009149832A1 (fr)
ZA (1) ZA201008821B (fr)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103017916B (zh) * 2012-12-05 2014-08-06 山东科技大学 新型高温抗冲蚀热电偶保护套管及其制备方法
CN106917109B (zh) * 2017-03-24 2018-10-12 宁波东方之光安全技术有限公司 一种用于电解槽阴极钢棒的测温装置及分布式测温系统

Family Cites Families (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH566402A5 (fr) 1972-07-18 1975-09-15 Alusuisse
US3975212A (en) * 1975-01-10 1976-08-17 Aluminum Company Of America Thermocouple protective composite tube
US4088509A (en) * 1977-03-04 1978-05-09 Mcdanel Refractory Porcelain Company Thermocouple protection tubes
JPS5791424A (en) * 1980-11-28 1982-06-07 Kobe Steel Ltd Temperature sensor for measuring temperature of molten aluminum or aluminum alloy
JPS57101730A (en) 1980-12-17 1982-06-24 Sumitomo Alum Smelt Co Ltd Protecting tube for measuring temperature of fused salt bath
US4560448A (en) 1982-05-10 1985-12-24 Eltech Systems Corporation Aluminum wettable materials for aluminum production
JPS629239A (ja) * 1985-07-05 1987-01-17 Omron Tateisi Electronics Co 高速応答型温度センサ
US4977001A (en) * 1986-08-01 1990-12-11 Vesuvius Crucible Company Protective cladding for a molybdenum substrate
US5310476A (en) 1992-04-01 1994-05-10 Moltech Invent S.A. Application of refractory protective coatings, particularly on the surface of electrolytic cell components
US5772324A (en) * 1995-10-02 1998-06-30 Midwest Instrument Co., Inc. Protective tube for molten metal immersible thermocouple
DE19714433C2 (de) 1997-04-08 2002-08-01 Celanese Ventures Gmbh Verfahren zur Herstellung einer Beschichtung mit einem Titanborid-gehald von mindestens 80 Gew.-%
DE102006013552B3 (de) 2006-03-24 2007-06-14 Maschinenfabrik Gustav Wiegard Gmbh & Co. Kg Unterpulverschweißverfahren zur Aufschweißung einer Nutzschicht auf einen Grundwerkstoff
DE102006013729A1 (de) 2006-03-24 2007-10-04 Esk Ceramics Gmbh & Co. Kg Gesinterter Werkstoff, sinterfähige Pulvermischung, Verfahren zur Herstellung des Werkstoffs und dessen Verwendung

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO2009149832A1 *

Also Published As

Publication number Publication date
CN102057262A (zh) 2011-05-11
BRPI0915048A2 (pt) 2015-10-27
CA2723943A1 (fr) 2009-12-17
WO2009149832A1 (fr) 2009-12-17
AU2009256994A1 (en) 2009-12-17
ZA201008821B (en) 2011-10-26
US8425112B2 (en) 2013-04-23
RU2010153997A (ru) 2012-07-20
DE102008027505A1 (de) 2010-01-28
US20110083958A1 (en) 2011-04-14
AU2009256994B2 (en) 2012-11-29

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