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WO1992002794A1 - Thermocouple equipe d'un isolant et d'une gaine ceramiques, et procede de fabrication - Google Patents

Thermocouple equipe d'un isolant et d'une gaine ceramiques, et procede de fabrication Download PDF

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Publication number
WO1992002794A1
WO1992002794A1 PCT/US1991/005432 US9105432W WO9202794A1 WO 1992002794 A1 WO1992002794 A1 WO 1992002794A1 US 9105432 W US9105432 W US 9105432W WO 9202794 A1 WO9202794 A1 WO 9202794A1
Authority
WO
WIPO (PCT)
Prior art keywords
insulator
sheath
ceramic
thermowell
thermocouple
Prior art date
Application number
PCT/US1991/005432
Other languages
English (en)
Inventor
Alfred R. Brenholts
Original Assignee
Brenholts Alfred R
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 Brenholts Alfred R filed Critical Brenholts Alfred R
Publication of WO1992002794A1 publication Critical patent/WO1992002794A1/fr

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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
    • 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

Definitions

  • Tjtle Thermocouple Equipped with Ceramic Insulator and Sheath and Method of Making Same
  • the present invention relates to temperature sensing apparatus and more particularly to those devices adapted for use with internal combustion engines, nuclear reactors, and other apparatus which require high temperature monitoring.
  • thermocouples particularly the "J” and “K” types, which have been inserted to monitor reaction temperatures.
  • the materials which jacketed these temperature sensing elements were typically formed from stainless steel or other conductive metals.
  • Much of the read-out instrumentation to which the thermocouple was attached required electrically ungrounded thermoelements. Accordingly, the metal jackets were electrically isolated from the iron-constantin or chromel-alumel thermoelement wires, typically by filling the space between the elements and jacket with powdered magnesium oxide.
  • the major deficiency of these previous thermocouple designs was the use of a hygroscopic mineral oxide to insulate the metallic thermoelement wires from the metal, protective jacket.
  • thermocouple The insulative capacity of the mineral oxide was compromised by water vapor invading the insulative material from the surrounding atmosphere. Even a slight amount of moisture in the powdered mineral oxide permitted formation of at least a temporary ground between the jacket and the thermocouple wires, thereby rendering the device non-functional. Over the years, this problem was tolerated, with many operators simply discontinuing use of the thermocouple and associated pyrometer for a period of time. However, with the growth in use of unmanned machinery, the constan monitoring required for computer control and computer monitoring, and the dangers posed by excessive temperatures in combustion reactions, the need for a durable and reliable thermocouple has become paramount.
  • thermocouples for example, use of thermocouples in internal combustion engines, particularly in monitoring exhaust gas temperatures, has become more widespread and critical.
  • conventional thermocouples were frequently sized to project deeply into the exhaust gas stream.
  • the metallic jackets for such elongated thermocouples were subject to considerable wear from exposure to hot and corrosive gases.
  • thermocouples employed tapered pipe threads for attachment to the exhaust manifolds. Removal and replacement typically involved a cutting torch, thus requiring engine shutdown, so that possibly combustible gases in a classified location (i.g., Class 1, Group D, Division 1 or 2) or other engine room were not ignited by sparks from the torch. Likewise, in the absence of a relatively permanent thermowell from which the spent thermocouple could be extracted, engine shutdown was required so that poisonous exhaust gases would not escape through the opening in the exhaust manifold formed when the old thermocouple was removed.
  • thermocouple which was substantially impervious to moisture, capable of withstanding substantial heat and vibration, less exposed to the corrosive forces within the high temperature environment, and easily rermved and replaced.
  • thermocouple which is the subject of the present invention basically comprises at least one thermoelement, a unitary ceramic insulator formed with at least one thermoelement-receiving passageway, and a unitary ceramic sheath formed with an insulator-receiving chamber.
  • the present thermocouple may be equipped with a metal shell formed with a sheath-receiving bore and provided with cooperative fastening means for securing the thermocouple in an operative position.
  • the above-mentioned cooperative fastening means includes standard spark plug threads, but may also use NPT threads. It is also preferable for the above-mentioned metal shell or jacket to be constructed in such a manner that a sensor end of the thermoelement extends into the sampling area less deeply than what has been the norm in the past.
  • Fig. 1 is a front elevational view of a thermocouple according to the present invention equipped with a threaded metallic outer shell;
  • Fig. 2 is a vertical sectional view taken along line 2-2 of Fig. 1 and particularly illustrating the manner in which the present thermocouple is constructed
  • Fig. 3 is a front elevational view of a thermocouple according to the present invention equipped with an elongated metal tube or thermowell
  • Fig. 4 is a vertical sectional view taken along line 4-4 of Fig. 3 and particularly illustrating the manner in which the present thermocouple is mounted in the tube or thermowell.
  • the present thermocouple basically comprises at least one and preferably two thermoelements 11, a unitary ceramic insulator 12 formed with at least one and preferably two relatively spaced apart thermoelement-receiving passageways 13, and a unitary ceramic sheath 14 formed with an insulator-receiving chamber 15.
  • the thermoelements are either iron-constantin or chromel-alumel wires, although other thermocouple alloys may be employed.
  • thermoelement insulator 12 is preferably an elongated, cylindrical article fabricated from high purity calcined alumina oxide powder which is milled and blended with some plasticizers and flexing agents to provide an homogeneous material of ninety-six percent alumina oxide content.
  • Other material compositions fall within the scope of the present invention which is not to be restricted to this one preferred embodiment.
  • this alumina oxide material is extruded to form the insulator 12, and is then sintered at elevated temperatures to form it to its final dimensions.
  • thermocouple junction 16 is provided at a sensor end of the ceramic insulator 12 adjacent to the closed end of the insulator-receiving chamber 15 of the ceramic sheath 1 .
  • the ceramic sheath 14 is manufactured by those methods commonly used to fabricate spark plug insulators from high purity alumina oxide formulas.
  • the calcined alumina oxide powder is milled and blended with plasticizers and fluxing agents to form an homogeneous material of ninety-six percent alumina oxide content. This material is then extruded or isostatically pressed into blanks. The resulting blank is then shaped to its unfired profile and dimensioned by lathe cutting or form grinding. Alternatively, the unformed alumina oxide material may be injection molded into the desired shape.
  • the ceramic sheath 14 is shaped, it is sintered under controlled firing conditions at elevated temperatures where it is reduced in size to the final dimensions, within standard commercial tolerances.
  • thermoelement-bearing ceramic insulator 12 is then coated with a high temperature alumina ceramic cement and inserted into the ceramic sheath 14. This assembly is then cured under controlled temperature conditions to set the adhesive.
  • fillers such as powdery fillers (e.g., sand, magnesium oxide) are not necessary in the assembly of the present invention. If the foregoing assembly is intended for use in an existing thermowell, then no more needs to be done to the assembly 10 other than to apply ANSI standard colored insulation to the thermoelement wires 11 so that the connection to the instrumentation (not shown) will result in accurate temperature levels being monitored.
  • an externally threaded gland 18 (Fig. 4) may be screwed onto the cooperative internal threads of the thermowell in surrounding and overlying relation to an upper shoulder portion 19 of the ceramic sheath 14.
  • the present ceramic thermocouple 10 may be fitted cartridge-style into a stainless steel tube 20.
  • This tube 20 may be somewhat permanent to the manifold or other housing into which it is installed and thus may constitute the above-referenced thermowell.
  • the subject tube or thermowell 20 is formed with a sheath-receiving chamber 21, the sensor end of which is closed.
  • the tube 20 is designed to project into the manifold or other chamber no more than one-quarter of the distance between opposing walls thereof.
  • the outer tube or thermowell 20 is equipped with external threads for cooperative engagement with a threaded coupling (not shown) on the manifold wall.
  • a hexagonal or octagonal head or shoulder 23 is formed on the stainless steel tube for extracting and fastening the tube to the manifold or chamber wall.
  • the present ceramic thermocouple 10 may be fitted into a steel shell 23 which is hermetically sealed to the ceramic sheath 14 in a manner well known in the art of sealing a spark plug insulator to its surrounding metal shell.
  • the shell is formed with standard SAE spark plug threads 24, a gasket 25 and a hexagonal or octagonal head 26.
  • the shell 23 is mounted on the ceramic thermocouple 10 so that the sensor end 16 of the thermocouple projects at least one inch into the chamber which is to be monitored. In the case of exhaust gas temperature monitoring, the sensor end 16 preferably extends less than one-half of the distance between opposing walls of the manifold in which it is mounted.
  • the shell may be provided with ISO or DIN standard spark plug threads, as well as with NPT threads.
  • the subject thermocouple may be replaced as easily as a spark plug and/or retrofitted into an existing threaded socket. Since the majority of prior art exhaust gas thermocouples have used one-fourth, three-eights, one-half or three-fourths inch NPT threads, it would be advantageous to employ 18 millimeter by 1.5 millimeter SAE or ISO spark plug threads.
  • a range of thread lengths would be provided, typically 12.7 millimeters, 18.5 millimeters and 25.4 millimeters. The 18.5 millimeter length would be virtually identical to the thread length of a one-half inch NPT pipe thread.
  • the manufacturer or operator may attach additional threads to the shell 23, thereby allowing for attachment of various hazardous location protective heads (not shown) for suppressing sparks and/or corrosion.
  • the present invention provides a thermocouple which is readily adapted for use in a variety of applications, either in combination with a metal tube or thermowell projecting into the area whose temperature is to be monitored or in association with a threaded metal shell similar in construction to those employed with spark plugs.
  • the present ceramic thermocouple 10 is preferably of cartridge design for ready replacement and for relatively permanent attachment to a spark plug-type threaded metal shell 23.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Measuring Temperature Or Quantity Of Heat (AREA)
  • Insulators (AREA)
  • Insulated Conductors (AREA)
  • Insulating Bodies (AREA)

Abstract

Un ensemble à thermocouple comprend un isolant céramique unitaire axialement allongé (12) formé d'une paire de passages s'étendant axialement (13) pour recevoir une paire de thermo-éléments (11), ainsi qu'une gaine céramique unitaire axialement alongé (14) pourvue d'une chambre (15) ayant une extrémité fermée pour recevoir l'isolant céramique allongé (12). Cet ensemble à thermocouple (10) peut être logé à la manière d'une cartouche dans un thermo-puits existant, ou être introduit dans un tube en acier inox (20) qui est ensuite vissé dans la paroi d'une chambre à contrôler, où peut être pourvu d'une enveloppe filetée extérieurement (23) du type bougie d'allumage pour être montée dans un collecteur d'échappement ou autre. De cette manière, un ensemble à thermocouple (10) durable et aisément remplaçable est obtenu.
PCT/US1991/005432 1990-08-02 1991-07-31 Thermocouple equipe d'un isolant et d'une gaine ceramiques, et procede de fabrication WO1992002794A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US56184390A 1990-08-02 1990-08-02
US561,843 1990-08-02

Publications (1)

Publication Number Publication Date
WO1992002794A1 true WO1992002794A1 (fr) 1992-02-20

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Country Status (3)

Country Link
AU (1) AU8620891A (fr)
CA (1) CA2088675A1 (fr)
WO (1) WO1992002794A1 (fr)

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5242226A (en) * 1991-07-27 1993-09-07 Hoechst Aktiengesellschaft Temperature-measuring instrument
US5456761A (en) * 1993-07-15 1995-10-10 Alcan International Limited High temperature and abrasion resistant temperature measuring device
US6632018B2 (en) * 2000-04-24 2003-10-14 Isuzu Motors Ltd. Thermocouple-type temperature-detecting device
US7080941B1 (en) * 2001-11-13 2006-07-25 Lam Research Corporation Temperature sensing system for temperature measurement in a high radio frequency environment
US7083329B2 (en) 2003-04-19 2006-08-01 Haldor Topsoe A/S Method of measuring high temperatures and instrument therefore
GB2435520A (en) * 2006-02-24 2007-08-29 Immergas Spa A Device For Measuring The Temperature Of A Fluid
WO2008115904A1 (fr) * 2007-03-19 2008-09-25 Babcock & Wilcox Technical Services Y-12, Llc Protection de thermocouple
EP2647973A1 (fr) 2012-04-06 2013-10-09 RETECH Spólka z o.o. Procédé de fabrication d'un capteur de température et le capteur de température
US9243936B2 (en) 2012-03-16 2016-01-26 Janesko Oy Measuring sensor
RU2607338C1 (ru) * 2015-11-25 2017-01-10 Общество с ограниченной ответственностью "Производственная компания "ТЕСЕЙ" Датчик температуры
CN110470408A (zh) * 2018-05-09 2019-11-19 特索纳有限责任两合公司 护罩热电偶
WO2022146576A1 (fr) * 2020-12-30 2022-07-07 Rosemount Inc. Sonde de température dotée d'un temps de réponse amélioré
US11846547B2 (en) 2016-11-03 2023-12-19 Danfoss A/S Tubular wire shielding for an exhaust gas temperature sensor arrangement, exhaust gas temperature sensor arrangement and method for assembling an exhaust gas temperature sensor arrangement

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107144595B (zh) * 2017-06-06 2023-09-01 南昌大学 热电偶和取样杯可重复利用的铸造铝合金热分析取样装置

Citations (10)

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Publication number Priority date Publication date Assignee Title
US3580078A (en) * 1969-04-16 1971-05-25 American Standard Inc Thermocouple failure indicating device
US3913058A (en) * 1972-07-25 1975-10-14 Ngk Spark Plug Co Thermosensor
US3923552A (en) * 1972-12-21 1975-12-02 Ppg Industries Inc Hermetically sealed thermocouple assembly
US3929511A (en) * 1974-02-25 1975-12-30 Jade Controls Inc Thermocouple assembly
US3960604A (en) * 1973-04-20 1976-06-01 Schwarzkopf Development Corporation Device for temperature measurements
US4002924A (en) * 1973-10-17 1977-01-11 Vdo Adolf Schindling Ag Device for measurement and/or control of temperature
US4018624A (en) * 1973-08-22 1977-04-19 Engelhard Minerals & Chemicals Corporation Thermocouple structure and method of manufacturing same
US4721533A (en) * 1986-08-01 1988-01-26 System Planning Corporation Protective structure for an immersion pyrometer
US4776705A (en) * 1987-06-11 1988-10-11 Texaco Inc. Thermocouple for use in a hostile environment
US4778537A (en) * 1986-10-25 1988-10-18 W. C. Heraeus Gmbh Method of making a thermocouple and so-made thermocouple

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3580078A (en) * 1969-04-16 1971-05-25 American Standard Inc Thermocouple failure indicating device
US3913058A (en) * 1972-07-25 1975-10-14 Ngk Spark Plug Co Thermosensor
US3923552A (en) * 1972-12-21 1975-12-02 Ppg Industries Inc Hermetically sealed thermocouple assembly
US3960604A (en) * 1973-04-20 1976-06-01 Schwarzkopf Development Corporation Device for temperature measurements
US4018624A (en) * 1973-08-22 1977-04-19 Engelhard Minerals & Chemicals Corporation Thermocouple structure and method of manufacturing same
US4002924A (en) * 1973-10-17 1977-01-11 Vdo Adolf Schindling Ag Device for measurement and/or control of temperature
US3929511A (en) * 1974-02-25 1975-12-30 Jade Controls Inc Thermocouple assembly
US4721533A (en) * 1986-08-01 1988-01-26 System Planning Corporation Protective structure for an immersion pyrometer
US4778537A (en) * 1986-10-25 1988-10-18 W. C. Heraeus Gmbh Method of making a thermocouple and so-made thermocouple
US4776705A (en) * 1987-06-11 1988-10-11 Texaco Inc. Thermocouple for use in a hostile environment

Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5242226A (en) * 1991-07-27 1993-09-07 Hoechst Aktiengesellschaft Temperature-measuring instrument
US5456761A (en) * 1993-07-15 1995-10-10 Alcan International Limited High temperature and abrasion resistant temperature measuring device
US6632018B2 (en) * 2000-04-24 2003-10-14 Isuzu Motors Ltd. Thermocouple-type temperature-detecting device
US7080941B1 (en) * 2001-11-13 2006-07-25 Lam Research Corporation Temperature sensing system for temperature measurement in a high radio frequency environment
RU2347200C2 (ru) * 2003-04-19 2009-02-20 Хальдор Топсеэ А/С Способ измерения высоких температур перерабатываемого потока и устройство для его осуществления
US7083329B2 (en) 2003-04-19 2006-08-01 Haldor Topsoe A/S Method of measuring high temperatures and instrument therefore
GB2435520A (en) * 2006-02-24 2007-08-29 Immergas Spa A Device For Measuring The Temperature Of A Fluid
US7621672B2 (en) 2007-03-19 2009-11-24 Babcock & Wilcox Technical Services Y-12, Llc Thermocouple shield
WO2008115904A1 (fr) * 2007-03-19 2008-09-25 Babcock & Wilcox Technical Services Y-12, Llc Protection de thermocouple
US9243936B2 (en) 2012-03-16 2016-01-26 Janesko Oy Measuring sensor
EP2647973A1 (fr) 2012-04-06 2013-10-09 RETECH Spólka z o.o. Procédé de fabrication d'un capteur de température et le capteur de température
RU2607338C1 (ru) * 2015-11-25 2017-01-10 Общество с ограниченной ответственностью "Производственная компания "ТЕСЕЙ" Датчик температуры
EA031036B1 (ru) * 2015-11-25 2018-11-30 Общество с ограниченной ответственностью "Производственная компания "ТЕСЕЙ" Датчик температуры
US11846547B2 (en) 2016-11-03 2023-12-19 Danfoss A/S Tubular wire shielding for an exhaust gas temperature sensor arrangement, exhaust gas temperature sensor arrangement and method for assembling an exhaust gas temperature sensor arrangement
CN110470408A (zh) * 2018-05-09 2019-11-19 特索纳有限责任两合公司 护罩热电偶
WO2022146576A1 (fr) * 2020-12-30 2022-07-07 Rosemount Inc. Sonde de température dotée d'un temps de réponse amélioré
US11650106B2 (en) 2020-12-30 2023-05-16 Rosemount Inc. Temperature probe with improved response time

Also Published As

Publication number Publication date
AU8620891A (en) 1992-03-02
CA2088675A1 (fr) 1992-02-03

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