Standard Test Method for Calibration of Refractory Metal Thermocouples Using a Radiation Thermometer

SCOPE
1.1 This test method covers the calibration of refractory metal thermocouples using a radiation thermometer as the standard instrument. This test method is intended for use with types of thermocouples that cannot be exposed to an oxidizing atmosphere. These procedures are appropriate for thermocouple calibrations at temperatures above 800°C (1472°F).
1.2 The calibration method is applicable to the following thermocouple assemblies:
1.2.1 Type 1—Bare-wire thermocouple assemblies in which vacuum or an inert or reducing gas is the only electrical insulating medium between the thermoelements.
1.2.2 Type 2—Assemblies in which loose fitting ceramic insulating pieces, such as single-bore or double-bore tubes, are placed over the thermoelements.
1.2.3 Type 2A—Assemblies in which loose fitting ceramic insulating pieces, such as single-bore or double-bore tubes, are placed over the thermoelements, permanently enclosed and sealed in a loose fitting metal or ceramic tube.
1.2.4 Type 3—Swaged assemblies in which a refractory insulating powder is compressed around the thermoelements and encased in a thin-walled tube or sheath made of a high melting point metal or alloy.
1.2.5Type 4—Thermocouple assemblies in which one thermoelement is in the shape of a closed-end protection tube and the other thermoelement is a solid wire or rod that is coaxially supported inside the closed-end tube. The space between the two thermoelements can be filled with an inert or reducing gas, or with ceramic insulating materials, or kept under vacuum.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

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ASTM E452-02 - Standard Test Method for Calibration of Refractory Metal Thermocouples Using a Radiation Thermometer
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:E452–02
Standard Test Method for
Calibration of Refractory Metal Thermocouples Using a
1
Radiation Thermometer
This standard is issued under the fixed designation E452; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope 2. Referenced Documents
1.1 This test method covers the calibration of refractory 2.1 ASTM Standards:
metal thermocouples using a radiation thermometer as the E344 Terminology Relating to Thermometry and Hydrom-
2
standard instrument. This test method is intended for use with etry
types of thermocouples that cannot be exposed to an oxidizing E563 Practice for Preparation and Use of Freezing Point
2
atmosphere. These procedures are appropriate for thermo- Reference Baths
couple calibrations at temperatures above 800°C (1472°F). E988 Temperature-Electromotive Force (EMF) Tables for
2
1.2 The calibration method is applicable to the following Tungsten-Rhenium Thermocouples
thermocouple assemblies: E1256 Test Methods for Radiation Thermometers (Single
2
1.2.1 Type 1—Bare-wire thermocouple assemblies in which Waveband Type)
vacuum or an inert or reducing gas is the only electrical E1751 Guide for Temperature Electromotive Force (EMF)
insulating medium between the thermoelements. Tables for Non-Letter Designated Thermocouple Combi-
2
1.2.2 Type 2—Assemblies in which loose fitting ceramic nations
insulating pieces, such as single-bore or double-bore tubes, are
3. Terminology
placed over the thermoelements.
1.2.3 Type 2A—Assemblies in which loose fitting ceramic 3.1 Definitions:
3.1.1 For definitions of terms used in this test method see
insulating pieces, such as single-bore or double-bore tubes, are
placed over the thermoelements, permanently enclosed and Terminology E344.
3.1.2 radiation thermometer, n—radiometer calibrated to
sealed in a loose fitting metal or ceramic tube.
indicate the temperature of a blackbody.
1.2.4 Type 3—Swaged assemblies in which a refractory
insulating powder is compressed around the thermoelements 3.1.2.1 Discussion—Radiationthermometersincludeinstru-
ments having the following or similar names: (1) optical
and encased in a thin-walled tube or sheath made of a high
melting point metal or alloy. radiation thermometer, (2) photoelectric pyrometer, (3) single
wavelength automatic thermometer, (4) disappearing filament
1.2.5 Type 4—Thermocouple assemblies in which one ther-
moelement is in the shape of a closed-end protection tube and pyrometer, (5) dual wavelength pyrometer or ratio radiation
thermometer, (6) visual optical thermometer, (7) infrared
the other thermoelement is a solid wire or rod that is coaxially
supported inside the closed-end tube. The space between the thermometer, (8) infrared pyrometer, and permutations on the
terms above as well as some manufacturer-specific names.
twothermoelementscanbefilledwithaninertorreducinggas,
or with ceramic insulating materials, or kept under vacuum. 3.2 Definitions of Terms Specific to This Standard:
3.2.1 automatic radiation thermometer, n—radiation ther-
1.3 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the mometer whose temperature reading is determined by elec-
tronic means.
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica- 3.2.2 disappearing filament pyrometer, n—radiation ther-
mometer that requires an observer to match visually the
bility of regulatory limitations prior to use.
brightness of a heated filament mounted inside the radiation
thermometer to that of the measured object.
1
This test method is under the jurisdiction of ASTM Committee E20 on
Temperature Measurementand is the direct responsibility of Subcommittee E20.04
on Thermocouples.
Current edition approved May 10, 2002. Published June 2002. Originally
2
published as E452–72. Last previous edition E452–97. Annual Book of ASTM Standards, Vol 14.03.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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E452
3.2.3 equalizing block, n—object, usually metal, that when 5. Significance and Use
placed in a nonuniform temperature region, has greater tem-
5.1 This test method is intended to be used by wire
perature uniformity (due to its relatively high thermoconduc-
producers and thermocouple manufacturers for certification of
tivity and mass) than the medium surrounding the object.
refractory metal thermocouples. It is intended to provide a
3.2.4 spectral emissivity, n—ratioofthespectralradiancea
...

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