1、Designation: E344 12Terminology Relating toThermometry and Hydrometry1This standard is issued under the fixed designation E344; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indi
2、cates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This terminology is a compilation of definitions of termsused by ASTM Committee E20 on Temperature Measurement.1.2 Terms with definitions generally applicable to
3、 the fieldsof thermometry and hydrometry are listed in 3.1.1.3 Terms with definitions applicable only to the indicatedstandards in which they appear are listed in 3.2.1.4 Information about the International Temperature Scaleof 1990 is given in Appendix X1.2. Referenced Documents2.1 ASTM Standards:2E
4、1 Specification for ASTM Liquid-in-Glass ThermometersE77 Test Method for Inspection and Verification of Ther-mometersE100 Specification for ASTM HydrometersE126 Test Method for Inspection, Calibration, and Verifica-tion of ASTM HydrometersE207 Test Method for Thermal EMF Test of Single Ther-moelemen
5、t Materials by Comparison with a ReferenceThermoelement of Similar EMF-Temperature PropertiesE220 Test Method for Calibration of Thermocouples ByComparison TechniquesE230 Specification and Temperature-Electromotive Force(EMF) Tables for Standardized ThermocouplesE452 Test Method for Calibration of R
6、efractory MetalThermocouples Using a Radiation ThermometerE574 Specification for Duplex, Base Metal ThermocoupleWire With Glass Fiber or Silica Fiber InsulationE585/E585M Specification for Compacted Mineral-Insulated, Metal-Sheathed, Base Metal ThermocoupleCableE601 Test Method for Measuring Electro
7、motive Force(emf) Stability of Base-Metal Thermoelement Materialswith Time in AirE608/E608M Specification for Mineral-Insulated, Metal-Sheathed Base Metal ThermocouplesE644 Test Methods for Testing Industrial Resistance Ther-mometersE667 Specification for Mercury-in-Glass, Maximum Self-Registering C
8、linical ThermometersE696 Specification for Tungsten-Rhenium Alloy Thermo-couple WireE710 Test Method for Comparing EMF Stabilities of Base-Metal Thermoelements in Air Using Dual, Simultaneous,Thermal-EMF Indicators3E780 Test Method for Measuring the Insulation Resistanceof Mineral-Insulated, Metal-S
9、heathed Thermocouples andThermocouple Cable at Room TemperatureE825 Specification for Phase Change-Type Disposable Fe-ver Thermometer for Intermittent Determination of HumanTemperatureE839 Test Methods for Sheathed Thermocouples andSheathed Thermocouple CableE879 Specification for Thermistor Sensors
10、 for ClinicalLaboratory Temperature MeasurementsE1061 Specification for Direct-Reading Liquid CrystalForehead ThermometersE1104 Specification for Clinical Thermometer Probe Cov-ers and SheathsE1112 Specification for Electronic Thermometer for Inter-mittent Determination of Patient TemperatureE1129/E
11、1129M Specification for Thermocouple Connec-torsE1137/E1137M Specification for Industrial Platinum Resis-tance ThermometersE1159 Specification for Thermocouple Materials, Platinum-Rhodium Alloys, and PlatinumE1256 Test Methods for Radiation Thermometers (SingleWaveband Type)E1299 Specification for R
12、eusable Phase-Change-Type Fe-ver Thermometer for Intermittent Determination of HumanTemperatureE1350 Guide for Testing Sheathed Thermocouples, Ther-mocouplesAssemblies, and Connecting Wires Prior to, andAfter Installation or Service1This terminology is under the jurisdiction of ASTM Committee E20 on
13、Temperature Measurement and is the direct responsibility of Subcommittee E20.91on Editorial and Terminology.Current edition approved May 1, 2012. Published June 2012. Originallyapproved in 1968. Last previous edition approved in 2010 as E344 10. DOI:10.1520/E0344-12.2For referenced ASTM standards, v
14、isit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Withdrawn. The last approved version of this historical standard is referencedon www.astm.org
15、.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.E1502 Guide for Use of Fixed-Point Cells for ReferenceTemperaturesE1594 Guide for Expression of TemperatureE1684 Specification for Miniature Thermocouple Connec-torsE1750 Guide for Use
16、 of Water Triple Point CellsE1751 Guide for Temperature Electromotive Force (EMF)Tables for Non-Letter Designated Thermocouple Combi-nations3E1965 Specification for Infrared Thermometers for Inter-mittent Determination of Patient TemperatureE2181/E2181M Specification for Compacted Mineral-Insulated,
17、 Metal-Sheathed, Noble Metal Thermocouplesand Thermocouple CableE2251 Specification for Liquid-in-Glass ASTM Thermom-eters with Low-Hazard Precision LiquidsE2593 Guide for Accuracy Verification of Industrial Plati-num Resistance Thermometers2.2 Other Standards, Supplementary Vocabularies, andSources
18、:4International Vocabulary of Basic and General Terms inMetrology (VIM) 1993Guide to the Expression of Uncertainty in Measurement(GUM) 1995IEC 61298-1 Process Measurement and Control DevicesGeneral Methods and Procedures for EvaluatingPerformance- Part 1: General Considerations53. Terminology3.1 Def
19、initions:accuracy, nof a temperature measurement, closeness ofagreement between the result of a temperature measurementand a true value of the temperature.DISCUSSIONAccuracy is a qualitative concept.base metal thermocouple, nthermocouple whose thermo-elements are composed primarily of base metals an
20、d theiralloys. (See also noble metal thermocouple; refractorymetal thermocouple.)DISCUSSIONBase metals used in thermoelements include nickel,iron, chromium, copper, aluminum. Letter-designated types E, J, K, T,and N are considered base metal thermocouples.bias, nthe scatter between the mean values o
21、f subsets ofdata, from each other or from the accepted value.blackbody, nthe perfect or ideal source of thermal radiantpower having a spectral distribution described by the Planckequation.DISCUSSIONThe term blackbody is often used to describe a furnaceor other source of radiant power which approxima
22、tes the ideal.bulb, nof a liquid-in-glass thermometer, reservoir for thethermometric liquid.calibration, n of a thermometer or thermometric system, theset of operations that establish, under specified conditions,the relationship between the values of a thermometricquantity indicated by a thermometer
23、 or thermometric systemand the corresponding values of temperature realized bystandards.DISCUSSION(1) The result of a calibration permits either theassignment of values of temperature to indicated values of thermomet-ric quantity or determination of corrections with respect to indications.(2)Acalibr
24、ation may also determine other metrological properties suchas the effect of influence quantities. (3) The result of a calibration maybe communicated in a document such as a calibration certificate or acalibration report. (4) The term calibration has also been used to referto the result of the operat
25、ions, to representations of the result, and to theactual relationship between values of the thermometric quantity andtemperature.calibration point, na specific value, established by a refer-ence, at which the indication or output of a measuring deviceis determined.Celsius, adjpertaining to or denoti
26、ng something related tothe expression of temperature in degrees Celsius.DISCUSSIONFor example, “A Celsius thermometer has a scalemarked in degrees Celsius.”center wavelength, na wavelength, usually near the middleof the band of radiant power over which a radiationthermometer responds, that is used t
27、o characterize its per-formance.DISCUSSIONThe value of the center wavelength is usually specifiedby the manufacturer of the instrument.clinical thermometer, nthermometer of any type designedto measure human body temperature.DISCUSSIONSome clinical thermometers may be designed to mea-sure the body te
28、mperature of animals.coaxial thermocouplea thermocouple consisting of a ther-moelement in wire form within a thermoelement in tubeform with the wire being electrically insulated from the tubeexcept at the measuring pensating extension wires, nthose extension wiresfabricated from materials basically
29、different in compositionfrom the thermocouple.DISCUSSIONThey have similar thermoelectric properties and withina stated temperature range effectively transfer the reference junction tothe other end of the plete immersion thermometer, na liquid-in-glass ther-mometer designed to indicate temperatures c
30、orrectly whenthe entire thermometer is exposed to the temperature beingmeasured. (Compare total immersion thermometer andpartial immersion thermometer.)connection head, na housing enclosing a terminal block foran electrical temperature-sensing device and usually pro-vided with threaded openings for
31、attachment to a protectingtube and for attachment of conduit.defining fixed point, nthermometric fixed point of anidealized system, to which a numerical value has beenassigned, used in defining a temperature scale.degree Celsius, C, nderived unit of temperature in the4Available from International Or
32、ganization for Standardization (ISO), 1, ch. dela Voie-Creuse, Case postale 56, CH-1211, Geneva 20, Switzerland, http:/www.iso.ch.5Available from International Electrotechnical Commission (IEC), 3 rue deVaremb, Case postale 131, CH-1211, Geneva 20, Switzerland, http:/www.iec.ch.E344 122International
33、 System of Units (SI). (See kelvin.)DISCUSSIONAt any temperature, an interval of one degree Celsius isthe same as an interval of one kelvin, by definition. For informationabout the relation between units and values of temperature expressed indifferent units, see Guide E1594.degree centigrade, nobsol
34、ete term. Use degree Celsius.degree Fahrenheit, F, nnon-SI unit of temperature com-monly used in the United States of America.DISCUSSIONAt any temperature, an interval of one degree Fahren-heit is the same as an interval of 5/9 kelvin (or 5/9 degree Celsius). Forinformation about the relation betwee
35、n units and values of temperatureexpressed in different units, see Guide E1594.electromotive force (emf), nthe electrical potential differ-ence which produces or tends to produce an electric current.error, nof a temperature measurement, result of a tempera-ture measurement minus a true value of temp
36、erature.extension wires, nthose having temperature-emf character-istics that when connected to a thermocouple effectivelytransfer the reference junction to the other end of the wires.(Compare compensating wires).Fahrenheit, adjpertaining to or denoting something relatedto the expression of temperatu
37、re in degrees Fahrenheit.DISCUSSIONFor example, “A Fahrenheit thermometer has a scalemarked in degrees Fahrenheit.”fixed point, n in thermometry, reproducible temperature ofequilibrium of a system of two or more phases underspecified conditions.freezing point, nfixed point of a single component syst
38、em inwhich liquid and solid phases are in equilibrium at aspecified pressure, usually 101 325 Pa, and the system islosing heat slowly. (Compare melting point.)grounded junction, n A measuring junction of a thermo-couple assembly that is electrically and physically connectedto its sheath. Also see St
39、yle G.DISCUSSIONThe term “grounded” has been historically accepted inthe field of thermometry to indicate the electrical connectivity of athermocouples measuring junction to its sheath; the term does notindicate whether or not the measuring junction is electrically connectedto earth or circuit groun
40、d.hysteresis, nThe property of a device or instrument wherebyit gives different output values in relation to its input valuesdepending upon the directional sequence in which the inputvalues have been applied. IEC 61298-1ice point, nthermometric fixed point of ice and watersaturated with air at a pre
41、ssure of 101 325 Pa.International Practical Temperature Scale (IPTS-48),nthe temperature scale adopted by the 11th GeneralConference on Weights and Measures in 1960 and replacedin 1968 by the International Practical Temperature Scale of1968.International Practical Temperature Scale of 1968 (IPTS-68)
42、, nthe temperature scale adopted by the 13th GeneralConference on Weights and Measures in 1968.DISCUSSIONThe IPTS-68 was superseded in 1990 by the Interna-tional Temperature Scale of 1990.International Temperature Scale of 1990 (ITS-90), nthetemperature scale prepared in accordance with instructions
43、of the 18th General Conference on Weights and Measures,and adopted on January 1, 1990.kelvin, K, nbase unit of temperature in the InternationalSystem of Units (SI).liquid-in-glass thermometer, na temperature-measuring in-strument whose indications are based on the temperaturecoefficient of expansion
44、 of a liquid relative to that of itscontaining glass bulb.lower range value, nthe lowest quantity that an instrumentis adjusted to measure.maximum permissible errors, nof a thermometer or ther-mometric system, extreme values permitted by regulation orspecification of the difference between the indic
45、ation of athermometer or thermometeric system and the true value oftemperature.DISCUSSIONThe term tolerance is sometimes used in ASTM stan-dards to represent this concept.maximum self-registering clinical thermometer, nclinicalthermometer designed to retain the indication of its maxi-mum measured te
46、mperature until reset.measuring junction, nthat junction of a thermocouplewhich is subjected to the temperature to be measured.melting point, nfixed point of a single component system inwhich liquid and solid phases are in equilibrium at aspecified pressure, usually 101 325 Pa, and the system isgain
47、ing heat slowly. (Compare freezing point.)noble metal thermocouple, nthermocouple whose thermo-elements are composed primarily of noble metals and theiralloys. (See also base metal thermocouple; refractorymetal thermocouple.)DISCUSSIONNoble metals used in thermoelements include platinum,rhodium, gol
48、d, palladium, iridium. Letter designated types B, R, and Sare considered noble metal thermocouples.partial immersion thermometer, na liquid-in-glass ther-mometer designed to indicate temperatures correctly whenthe bulb and a specified part of the stem are exposed to thetemperatures being measured. (
49、Compare complete immer-sion thermometer and total immersion thermometer.)Peltier coefficient, nthe reversible heat which is absorbed orevolved at a thermocouple junction when unit current passesin unit time.platinum 27 (Pt-27), nthe platinum standard to which theNational Bureau of Standards referred thermoelectric mea-surements prior to 1973.platinum 67 (Pt-67), nthe platinum standard used by theNational Bureau of Standards after 1972 as the reference towhich thermoelectric measurements are referred.
