GB2428517A - Ceramic thermocouple - Google Patents

Ceramic thermocouple Download PDF

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Publication number
GB2428517A
GB2428517A GB0514994A GB0514994A GB2428517A GB 2428517 A GB2428517 A GB 2428517A GB 0514994 A GB0514994 A GB 0514994A GB 0514994 A GB0514994 A GB 0514994A GB 2428517 A GB2428517 A GB 2428517A
Authority
GB
United Kingdom
Prior art keywords
tube
rod
coating
thermocouple
ceramic
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Withdrawn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
GB0514994A
Other versions
GB0514994D0 (en
Inventor
Paul Lincoln Bowen
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.)
Weston Aerospace Ltd
Original Assignee
Weston Aerospace Ltd
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 Weston Aerospace Ltd filed Critical Weston Aerospace Ltd
Priority to GB0514994A priority Critical patent/GB2428517A/en
Publication of GB0514994D0 publication Critical patent/GB0514994D0/en
Priority to DE602006002445T priority patent/DE602006002445D1/en
Priority to EP06253753A priority patent/EP1746397B1/en
Priority to CA2552124A priority patent/CA2552124C/en
Priority to US11/489,713 priority patent/US7771116B2/en
Publication of GB2428517A publication Critical patent/GB2428517A/en
Withdrawn legal-status Critical Current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
    • G01K7/00—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements
    • G01K7/02—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using thermoelectric elements, e.g. thermocouples
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
    • G01K7/00—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements
    • G01K7/02—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using thermoelectric elements, e.g. thermocouples
    • G01K7/04—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using thermoelectric elements, e.g. thermocouples the object to be measured not forming one of the thermoelectric materials
    • G01K7/06—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using thermoelectric elements, e.g. thermocouples the object to be measured not forming one of the thermoelectric materials the thermoelectric materials being arranged one within the other with the junction at one end exposed to the object, e.g. sheathed type

Abstract

The thermocouple comprises a molybdenum tube 3 and a silicon carbide rod 2. The hot junction is defined by a molybdenum silicide coating on the inner wall of the tube and a silicon carbide rod 2. An aluminium oxide coating on the rod separates the rod from the coating in regions away from the junction so that the hot junction is formed in the tip region of the rod/tube assembly only.

Description

Ceramic Thermocouple The present invention relates to a thermocouple
assembly and more particularly to a thermocouple formed by two ceramic elements joined at a junction.
It is known to produce thermocouples which measure temperature by measuring the electromotive force generated at the junction of two semiconducting ceramics. GB 2, 288, 908 (Rowan Technologies Limited) discloses a ceramic thermocouple comprising two ceramics elements. The first ceramic element is a silicon carbide tube closed at one end, and the second ceramic element is a molybdenum disilicide rod placed inside the tube. The molybdenum disilicide rod is pressed by a spring arrangement against the closed end of the silicon carbide tube to form a thermocouple junction. The remainder of the molybdenum disilicide rod is separated from the silicon carbide tube by aluminium oxide washers ranged at intervals along the rod.
A problem of known ceramic thermocouples including that disclosed in GB 2, 288, 908 is their lack of mechanical integrity. They are not sufficiently rugged to withstand difficult environments such as a gas turbine.
The present invention provides a thermocouple as defined in independent claims 1 and 6 to which reference should now be made. Preferred features of the invention are set out in claims 2 to 5 to which reference should now be made.
By way of illustration of the invention, a preferred embodiment of the invention will now be described with reference to the aftached figures in which: Figure 1 is a cross-section through a thermocouple embodying the invention; Figure 2 is a magnified cross-section through item 2 of Figure 1; Figure 3 is a magnified section through item 3 of Figure 1; and Figure 4 is a magnified view of the circled portion A of Figure 1.
Referring to Figure 1, a thermocouple assembly 10 comprises two elements 2, 3 of semi-conducting ceramic material. The first element 2 is a silicon carbide rod. The second element 3 is a molybdenum tube having a coating on its inner wall of molybdenum disilicide for contacting an end portion of the silicon carbide rod.
The silicon carbide rod has a tapered end portion and is coated with an insulator such as aluminium oxide along its non-tapered portion. The rod has a diameter of about 4.5mm.
The molybdenum tube has an internal tapered portion at one end. The shape and dimensions of the internal bore of the tube (including the taper of the molybdenum tube) match the external shape and dimension (including the taper) of the silicon carbide tube so that when the rod is pushed into the tube the rod is in contact with the tube along its length. The molybdenum tube has an external diameter of about 6.5mm and an internal diameter of about 4.5mm.
The molybdenum tube is coated with an insulator such as aluminium oxide on its internal and external surfaces. The internal bore of the tube has an additional coating of molybdenum disilicide on top of the aluminium oxide to form an element of semi-conducting ceramic.
As illustrated in figure 4, the molybdenum disilicide coating on the tube is in contact with the silicon carbide rod only where the respective tapers of the rod and tube are in contact. The insulating aluminium oxide coating on the non- tapered portion of the silicon carbide rod separates the remainder of the semi- conducting silicon carbide from the remainder of the molybdenum disilicide coating.
The junction at the respective tapered end portions between the different semi-conducting elements defined by the silicon carbide rod and molybdenum disilicide coating produce an electromotive force dependent on the temperature of the junction and thereby form a thermocouple.

Claims (6)

  1. Claims 1. A thermocouple assembly comprising two different ceramics in
    contact with each other at a thermocouple junction, wherein the assembly comprises a coating of a first ceramic on a metal tube, and a rod having a surface of a second ceramic, the rod being inside the tube with at least part of said rod surface in contact with said tube coating - to define the junction.
  2. 2. A thermocouple assembly according to claim 1 wherein the tube is a metal tube coated with an insulating material and the coating of the first ceramic is on top of the insulating coating.
  3. 3. A thermocouple assembly according to any preceding claim wherein the rod is a rod of the second ceramic.
  4. 4. A thermocouple assembly according to any preceding claim wherein portions of the tube and rod have corresponding and matching tapers so that the respective tapered portions of the tube and rod are in intimate contact and define the thermocouple junction.
  5. 5. A thermocouple assembly according to any preceding claim comprising a molybdenum tube with an internal tapered portion and having a first coating of aluminium oxide on its inner and outer surfaces and a second coating of molybdenum disilicide on its inner surface, and a rod of silicon carbide inside the tube and having a tapered portion matching the tapered portion of the tube so as to form contact therewith, the silicon carbide tube also having a coating of aluminium oxide on its non-tapered portion so as to electrically separate the non-tapered portions of the rod and rube.
  6. 6. A thermocouple assembly substantially as hereinbefore described with reference to the attached figures.
GB0514994A 2005-07-21 2005-07-21 Ceramic thermocouple Withdrawn GB2428517A (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
GB0514994A GB2428517A (en) 2005-07-21 2005-07-21 Ceramic thermocouple
DE602006002445T DE602006002445D1 (en) 2005-07-21 2006-07-18 Ceramic thermocouple
EP06253753A EP1746397B1 (en) 2005-07-21 2006-07-18 Ceramic thermocouple
CA2552124A CA2552124C (en) 2005-07-21 2006-07-18 Ceramic thermocouple
US11/489,713 US7771116B2 (en) 2005-07-21 2006-07-20 Ceramic thermocouple

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB0514994A GB2428517A (en) 2005-07-21 2005-07-21 Ceramic thermocouple

Publications (2)

Publication Number Publication Date
GB0514994D0 GB0514994D0 (en) 2005-08-31
GB2428517A true GB2428517A (en) 2007-01-31

Family

ID=34976323

Family Applications (1)

Application Number Title Priority Date Filing Date
GB0514994A Withdrawn GB2428517A (en) 2005-07-21 2005-07-21 Ceramic thermocouple

Country Status (5)

Country Link
US (1) US7771116B2 (en)
EP (1) EP1746397B1 (en)
CA (1) CA2552124C (en)
DE (1) DE602006002445D1 (en)
GB (1) GB2428517A (en)

Families Citing this family (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102008007740B3 (en) * 2008-02-05 2009-07-30 Uhde Gmbh Device for measuring high temperatures, particularly temperature of hot gases, which are formed on coal combustion or gasification process, includes thermocouple pair containing two ceramic materials
KR101262698B1 (en) * 2010-12-13 2013-05-15 두산중공업 주식회사 Device for measuring plane temperature distribution of an electrode for the fuel cell
JP6421690B2 (en) * 2014-07-17 2018-11-14 株式会社デンソー Temperature sensor
DE102014227033A1 (en) 2014-12-30 2016-06-30 Siemens Aktiengesellschaft Thermocouple and method for applying such
FR3034463B1 (en) * 2015-04-02 2017-05-19 Hispano Suiza Sa OIL SPRINKLER FOR TURBOMACHINE
US10690551B2 (en) * 2016-02-12 2020-06-23 Rhode Island Council On Postsecondary Education Temperature and thermal gradient sensor for ceramic matrix composites and methods of preparation thereof
US10371588B2 (en) 2016-07-01 2019-08-06 Rhode Island Council On Postsecondary Education High resolution strain gages for ceramic matrix composites and methods of manufacture thereof
US10782190B1 (en) 2017-12-14 2020-09-22 University Of Rhode Island Board Of Trustees Resistance temperature detector (RTD) for ceramic matrix composites
DE102020203166A1 (en) 2020-03-12 2021-09-16 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung eingetragener Verein Sensor structure for determining high temperatures and method for manufacturing the sensor structure
DE102020113903B3 (en) 2020-05-25 2021-11-18 Temperaturmeßtechnik Geraberg GmbH Thermocouple for measuring high temperatures and method for drift detection on a thermocouple

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3305405A (en) * 1963-07-17 1967-02-21 Charles P Jamieson Graphite thermocouples and method of making
US4450314A (en) * 1981-08-14 1984-05-22 Mtu Motoren-Und Turbinen Union Munchen Gmbh Thermocouple for measuring temperatures and method of making the thermocouple
JPS63169081A (en) * 1987-01-07 1988-07-13 Tokai Kounetsu Kogyo Kk Thermocouple consisting of silicon carbide and carbon
US5986261A (en) * 1996-04-29 1999-11-16 Nanoptics, Inc. Tapered structure suitable for microthermocouples microelectrodes, field emission tips and micromagnetic sensors with force sensing capabilities
GB2352816A (en) * 1999-08-04 2001-02-07 Bowthorpe Components Ltd A thermistor probe or catheter comprising a temperature dependent material placed between concentric conductors

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Publication number Priority date Publication date Assignee Title
US4721533A (en) * 1986-08-01 1988-01-26 System Planning Corporation Protective structure for an immersion pyrometer
DE3636468C1 (en) * 1986-10-25 1987-09-17 Heraeus Gmbh W C Sheathed wire thermocouple
US5221916A (en) * 1988-05-02 1993-06-22 Fluid Components, Inc. Heated extended resistance temperature sensor
US5336851A (en) * 1989-12-27 1994-08-09 Sumitomo Electric Industries, Ltd. Insulated electrical conductor wire having a high operating temperature
US6012565A (en) * 1997-05-07 2000-01-11 Cummins-Allison Corp. Intelligent currency handling system
US5456761A (en) * 1993-07-15 1995-10-10 Alcan International Limited High temperature and abrasion resistant temperature measuring device
JPH07181085A (en) * 1993-12-24 1995-07-18 Sumitomo Electric Ind Ltd Thermocouple having insulated temperature measuring contact and production thereof
US5520461A (en) * 1994-03-02 1996-05-28 Alliedsignal Inc. Airtight thermocouple probe
GB2288908B (en) 1994-04-27 1997-08-20 Rowan Technologies Ltd Ceramic thermocouple
US6124579A (en) * 1997-10-06 2000-09-26 Watlow Electric Manufacturing Molded polymer composite heater
US6337470B1 (en) * 1997-10-06 2002-01-08 Watlow Electric Manufacturing Company Electrical components molded within a polymer composite
KR19990066851A (en) * 1998-01-12 1999-08-16 카와무라 히데오 Thermocouples for Metal Melt Temperature Measurement
EP1677087A1 (en) * 2004-12-21 2006-07-05 Vesuvius Crucible Company Thermocouple assembly and method of use

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3305405A (en) * 1963-07-17 1967-02-21 Charles P Jamieson Graphite thermocouples and method of making
US4450314A (en) * 1981-08-14 1984-05-22 Mtu Motoren-Und Turbinen Union Munchen Gmbh Thermocouple for measuring temperatures and method of making the thermocouple
JPS63169081A (en) * 1987-01-07 1988-07-13 Tokai Kounetsu Kogyo Kk Thermocouple consisting of silicon carbide and carbon
US5986261A (en) * 1996-04-29 1999-11-16 Nanoptics, Inc. Tapered structure suitable for microthermocouples microelectrodes, field emission tips and micromagnetic sensors with force sensing capabilities
GB2352816A (en) * 1999-08-04 2001-02-07 Bowthorpe Components Ltd A thermistor probe or catheter comprising a temperature dependent material placed between concentric conductors

Also Published As

Publication number Publication date
GB0514994D0 (en) 2005-08-31
US7771116B2 (en) 2010-08-10
EP1746397B1 (en) 2008-08-27
CA2552124C (en) 2011-08-23
CA2552124A1 (en) 2007-01-21
US20070029303A1 (en) 2007-02-08
DE602006002445D1 (en) 2008-10-09
EP1746397A1 (en) 2007-01-24

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WAP Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1)