1、Designation: E2820 11Standard Test Method forEvaluating Thermal EMF Properties of Base-MetalThermocouple Connectors1This standard is issued under the fixed designation E2820; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year
2、 of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This standard describes a thermal emf test method forbase-metal thermocouple connectors including Types E, J, K,N
3、and T. Standard connectors such as found in SpecificationsE1129/E1129M and E1684 as well as non-standard connectorconfigurations and connector components can be evaluatedusing this method.1.2 The measured emf is reported as an equivalent tempera-ture deviation or error relative to a reference thermo
4、couple ofthe same type. This method can be used to verify deviationsintroduced by the connector greater than or equal to 1C.1.3 The connector is tested with thermocouple contactsaxially aligned with a temperature gradient using a specifiedthermal boundary condition. The actual temperature difference
5、developed across the connector and corresponding error willdepend on the connector design.1.4 Connector contacts are often fabricated from raw mate-rials having temperature-emf relationships in accordance withSpecification E230. However, verifying Specification E230tolerances is not within the scope
6、 of this method.1.5 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.6 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard t
7、o establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E220 Test Method for Calibration of Thermocouples ByComparison TechniquesE230 Specification and Temperature-Electromotive Force(EMF)
8、 Tables for Standardized ThermocouplesE344 Terminology Relating to Thermometry and Hydrom-etryE563 Practice for Preparation and Use of an Ice-Point Bathas a Reference TemperatureE1129/E1129M Specification for Thermocouple Connec-torsE1684 Specification for Miniature Thermocouple Connec-torsE2488 Gui
9、de for the Preparation and Evaluation of LiquidBaths Used for Temperature Calibration by Comparison3. Terminology3.1 DefinitionsThe definitions given in TerminologyE344 apply to the terms used in this standard.4. Summary of Test Method4.1 The connector is tested as part of a thermocouple circuitand
10、compared to a reference thermocouple of the same typeand material lot.4.2 Measurements are made while the connector is sub-jected to a temperature gradient established by a specifiedboundary condition.4.3 Performance is evaluated at a fixed position within adry-well furnace or stirred liquid bath (M
11、ethod 1 or 2Arespectively) or variable position within a stirred liquid bath(Method 2B). The latter method can be used to survey theconnector to identify a position within the thermal gradient thatproduces a maximum output deviation.4.4 Results are interpreted relative to the properties of therefere
12、nce thermocouple.5. Significance and Use5.1 A thermocouple connector, exposed to a temperaturedifference, contributes to the output of a thermocouple circuit.The output uncertainty allocated to the connector depends onthe connector design and temperature gradient.1This test method is under the juris
13、diction of ASTM Committee E20 onTemperature Measurement and is the direct responsibility of Subcommittee E20.04on Thermocouples.Current edition approved May 1, 2011. Published June 2011 DOI: 10.1520/E282011.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer
14、 Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.2 Connector performance can be classi
15、fied based on theresults of this method and used as part of a componentspecification.5.3 The method can be used as an engineering tool forevaluating different connector designs tested under similarthermal conditions.6. Apparatus6.1 The apparatus includes a temperature source, thermo-couple readout d
16、evice or voltmeter and ice-bath as shown inFig. 1 and Fig. 2.An ice-bath is needed only if the readout doesnot provide cold junction compensation.6.2 The thermocouple readout device or voltmeter shallhave two or more channels and have equivalent temperatureresolution of at least 0.1C. The difference
17、 between channelsshall not exceed the equivalent of 0.1C when supplied withthe same voltage input.6.3 The temperature source heats the measuring junctionsand produces a temperature gradient across the connector. Thesource is either a dry-well furnace or stirred liquid bathdepending on the specified
18、method.6.3.1 Method 1a temperature controlled dry-well furnacewith an immersion depth of at least 100 mm and the capabilityof maintaining the specified test temperature within 1C.6.3.2 Method 2a temperature controlled stirred liquidbath of non-conductive fluid with an immersion depth of atleast 150
19、mm and the capability of maintaining the specifiedtemperature within 1C. Comparison calibration baths asdescribed in Guide E2488 are suitable for this test.7. Hazards7.1 Review the Material Safety Data Sheet (MSDS) beforeusing a fluid in a temperature-controlled bath. Temperaturelimits, flammability
20、, vapor pressure, toxicity and chemicalstability are important factors in determining a suitable fluid.8. Preparation of Apparatus8.1 The apparatus requires a dual thermocouple circuit witha common measuring junction. The circuit shall be fabricatedfrom the same spool of wire. Except for the connect
21、or undertest, the length of wire shall be continuous without splices orother connections between the measuring junction and thereadout device.8.2 The thermocouple wire shall carry the same letterdesignation (for example, Type K) as the connector under test.The wire shall conform to the special toler
22、ance in SpecificationE230 over the range of 0C to the maximum specifiedconnector test temperature. The wire size shall be 24 gage (0.5mm) unless specified otherwise.8.3 The test connector shall be installed approximately 70mm from the measuring junction. When testing in a dry-wellfurnace per Method
23、1, a thermally and electrically insulatinggasket shall be used to seal the furnace entrance, accentuatingthe temperature gradient across the connector. Placing thegasket between the plug and jack is generally the easiest wayto control the position of the connector within the temperaturegradient (Fig
24、. 3a).FIG. 1 Test Schematic Using a Readout Device with Cold Junction Compensation, Providing Temperature Indications of the TestThermocouple Ttestand Reference Thermocouple TrefE2820 1128.4 When testing per Method 2 in a liquid bath, theconnector and a portion of the thermocouple shall be attachedt
25、o an insulating rod to support the sample during the test (Fig.3b).8.5 The 0C reference junctions (if needed) shall be pre-pared using the same approach used for thermocouple calibra-tion per Test Method E220. The copper wires shall be thermo-couple type TP per Specification E230 and shall all be cu
26、t fromthe same spool.8.6 The 0C ice-bath (if needed) shall be prepared inaccordance Practice E563.9. Procedure9.1 Set up the temperature source for the specified testcondition (Table 1).9.2 Connect both thermocouple circuits to the readoutdevice or meter. With the common measuring junction andconnec
27、tor at room temperature, verify the difference betweencircuits is within the equivalent of 0.1C. For voltage outputs,the difference expressed in C is determined as follows.DT 5 Etest2Eref!/S (1)where:Eref= voltage output of reference thermocouple, mVEtest= voltage output of test thermocouple (with c
28、onnec-tor), mVS = nominal Seebeck coefficient (see Appendix X1),mV/CFIG. 2 Test Schematic Using a Voltmeter and Reference Junctions at 0CE2820 1139.3 Method 1using a dry-well furnace at fixed depth.9.3.1 Insert the thermocouples into the furnace with theconnector positioned at the furnace entrance w
29、ith an insulatinggasket.9.3.2 Adjust the furnace temperature until the referencethermocouple channel indicates the specified test temperaturewithin 6 1C.9.3.3 Allow the thermocouple and connector to equilibrateas indicated by a stable output difference between the referenceand test thermocouples. Th
30、is typically requires 15 to 30 min,depending on connector design.9.3.4 Record the output of the test and reference thermo-couples.9.4 Method 2Ausing a stirred liquid bath at fixed depth.9.4.1 Insert the thermocouple into the bath with the connec-tor suspended just above the bath surface (approximate
31、ly 70mm).9.4.2 Adjust the bath temperature until the reference ther-mocouple channel indicates the specified test temperaturewithin 6 1C.9.4.3 Lower the thermocouple to the specified connectorimmersion depth.9.4.4 Allow the thermocouple and connector to equilibrateas indicated by a stable output dif
32、ference between the referenceand test thermocouples. This typically requires 15 to 30 min,depending on connector design.9.4.5 Record the output of the test and reference thermo-couples.9.5 Method 2Busing a stirred liquid bath at variabledepth.9.5.1 Insert the thermocouple into the bath with the conn
33、ec-tor suspended just above the bath surface (approximately 70mm).9.5.2 Adjust the bath temperature until the reference ther-mocouple channel indicates the specified test temperaturewithin 6 1C.9.5.3 Allow the thermocouple and connector to equilibrateas indicated by a stable output difference betwee
34、n the referenceand test thermocouples. This typically requires 15 to 30 min,depending on connector design.9.5.4 Record the output of the test and reference thermo-couples.9.5.5 Repeat the stabilization step of 9.5.3 and the measure-ment of 9.5.4 at incrementally increasing depths until theconnector
35、is completely immersed. Each step shall not exceed25 % of the connector length.10. Calculation and Interpretation of Results10.1 The connector error is calculated from the differencebetween the test and reference thermocouple outputs.10.1.1 When using a temperature readout device:Error 5 Ttest Tref(
36、2)where:Ttest= temperature indicated by the test thermocouple(with connector), CTref= temperature indicated by the reference thermo-couple, C10.1.2 When using a voltmeter:FIG. 3 Connector Hook-Up Examples: (a) E1129 Connector Prepared for Method 1 Testing in a Dry-Well Furnace and (b) A TerminalAsse
37、mbly Prepared for Method 2 Testing in a Stirred Liquid BathTABLE 1 Standard Test ConditionsCondition Nominal TestTemperature (C)A65B 100C 200D 260or user specifiedE2820 114Error 5 Etest Eref!/S (3)where:Etest= output of test thermocouple (with connector), mVEref= output of reference thermocouple, mV
38、S = nominal Seebeck coefficient (see Appendix X1),mV/C10.2 The connector error can be positive or negative. Whentesting at a fixed position or depth, the connector error typicallychanges linearly with test temperature as shown in Fig. 4.10.3 When surveying the connector at multiple immersiondepths (
39、Method 2B), the connector is characterized by themaximum error without regard to sign.10.4 When the connector is completely immersed in thebath, the connector will be approximately isothermal and theresulting error should be zero.11. Report11.1 The report shall include the following minimum infor-ma
40、tion:11.1.1 Connector identification,11.1.2 Test method and specified connector immersiondepth, if applicable, and11.1.3 Test condition (Table 1) or specified test temperatureand corresponding connector error expressed in C.12. Precision and Bias12.1 PrecisionThe repeatability standard deviation de-
41、pends on the connector design and test condition. For Speci-fication E1129/E1129M connectors, the repeatability standarddeviation for Method 1 is typically less than 0.1C. Thereproducibility of the test method is being determined and willbe available in January 2012.12.2 BiasNo information can be pr
42、esented on the bias ofmeasuring connector emf because no material having anacceptable reference value is available.13. Keywords13.1 connector emf; thermocouple connector; thermocouplecontact; thermocouple pin; thermocouple socket; thermocoupleterminalE2820 115APPENDIX(Nonmandatory Information)X1. SE
43、EBECK COEFFICIENT CALCULATIONX1.1 The Seebeck coefficient describes the rate of changeof thermal emf with temperature at a given temperature. Thisstandard uses the nominal Seebeck coefficient for the specifiedthermocouple type.X1.2 The Seebeck coefficient can be estimated from thetabulated values of
44、 emf versus temperature included in Speci-fication E230.S 5 E2 E1!/T2 T1! (X1.1)where:Tt= nominal test temperature, CT2=Tt+ 1CT1=Tt 1CE2= nominal emf at T2per Specification E230,mVE1= nominal emf at T1per Specification E230,mVX1.2.1 For example, the Seebeck coefficient for a Type Kthermocouple teste
45、d at 100C is calculated as follows:T2= 101CT1= 99CE2= 4.138 mVE1= 4.055 mVS = (4.138 4.055)/(101 99) = 0.041 mV/CASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advi
46、sed that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either
47、reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If
48、 you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individ
49、ual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).FIG. 4 Example of Connector Error Versus Temperature for an E1129 Type K Connector Tested per Method 1E2820 116
