1、Designation: E2821 13Standard Specification forCompacted Mineral-Insulated, Metal-Sheathed Cable Usedin Industrial Resistance Thermometers1This standard is issued under the fixed designation E2821; the number immediately following the designation indicates the year oforiginal adoption or, in the cas
2、e of revision, the year 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 specification covers the requirements forcompacted, mineral-insulated, metal-sheathed
3、(MIMS) cablesused to manufacture metal-sheathed, industrial resistance ther-mometers referred to in this document as Resistance Tempera-ture Detectors or RTDs.1.2 The materials of construction include copper, nickel-clad copper, copper-45 % nickel (constantan), or nickelconductors, an austenitic sta
4、inless steel or nickel-chromiumalloy sheath, and either magnesia (MgO) or alumina (Al2O3)insulation.1.3 The cable diameter is between 0.093 and 0.500 in. (2.33and 12.70 mm) and contains between two and eightconductors, set in various design configurations and wirespacings.1.4 The values of temperatu
5、re in this specification are basedon the International Temperature Scale of 1990 (ITS-90).1.5 The values stated in inch-pound units are to be regardedas standard. The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered stan
6、dard.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 to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referen
7、ced Documents2.1 The latest issues of the following documents form a partof this specification to the extent specified herein. In the eventof a conflict between this specification and other specificationsreferenced herein, this specification shall take precedence.2.2 Due to the similarity between Co
8、mpacted MIMS Ther-mocouple Cable and Compacted MIMS Cable, some Thermo-couple ASTM Standards may apply.2.3 ASTM Standards:2A213/A213M Specification for Seamless Ferritic and Aus-tenitic Alloy-Steel Boiler, Superheater, and Heat-Exchanger TubesA249/A249M Specification for Welded Austenitic SteelBoile
9、r, Superheater, Heat-Exchanger, and CondenserTubesA269 Specification for Seamless and Welded AusteniticStainless Steel Tubing for General ServiceA632 Specification for Seamless and Welded AusteniticStainless Steel Tubing (Small-Diameter) for General Ser-viceB163 Specification for Seamless Nickel and
10、 Nickel AlloyCondenser and Heat-Exchanger TubesB167 Specification for Nickel-Chromium-Iron Alloys (UNSN06600, N06601, N06603, N06690, N06693, N06025,N06045, and N06696), Nickel-Chromium-Cobalt-Molybdenum Alloy (UNS N06617), and Nickel-Iron-Chromium-Tungsten Alloy (UNS N06674) Seamless Pipeand TubeB5
11、16 Specification forWelded Nickel-Chromium-IronAlloy(UNS N06600, UNS N06603, UNS N06025, and UNSN06045) TubesE344 Terminology Relating to Thermometry and Hydrom-etryE780 Test Method for Measuring the Insulation Resistanceof Mineral-Insulated, Metal-Sheathed Thermocouples andThermocouple Cable at Roo
12、m TemperatureE839 Test Methods for Sheathed Thermocouples andSheathed Thermocouple CableE1137/E1137M Specification for Industrial Platinum Resis-tance ThermometersE1652 Specification for Magnesium Oxide and AluminumOxide Powder and Crushable Insulators Used in theManufacture of Metal-Sheathed Platin
13、um ResistanceThermometers, Base Metal Thermocouples, and NobleMetal Thermocouples1This specification is under the jurisdiction of ASTM Committee E20 onTemperature Measurement and is the direct responsibility of Subcommittee E20.03on Resistance Thermometers.Current edition approved May 1, 2013. Publi
14、shed July 2013. DOI: 10.1520/E2821-132For referenced ASTM standards, visit 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.Copyright ASTM Internati
15、onal, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States12.4 ANSI Standard:3ANSI B46.1 Surface Texture, Surface Roughness, Wavinessand Lay3. Terminology3.1 DefinitionsThe definitions given in Terminology E344shall apply to this specification.3.2 Definitions:3.2.1 lot
16、, na quantity of finished MIMS RTD cablemanufactured from tubing from the same heat, wire from thesame spool and heat, and insulation from the same batch, thenassembled and processed together under controlled productionconditions to the required final outside diameter.3.2.2 raw material, ntubing, in
17、sulation, and wires used infabrication of MIMS RTD cable.4. Significance and Use4.1 MIMS RTD cable may be used as follows:4.1.1 As a cable for attaching the sensing element to asensor termination within a thermometer (see SpecificationE1137/E1137M).4.1.2 As an extension cable connecting a thermomete
18、r toanother device.5. Ordering Information and Basis for Purchase5.1 The purchasing documents shall specify the followingoptions:5.1.1 The total length of finished MIMS RTD cable or thelength of each piece of finished MIMS RTD cable.5.1.2 The material and number of conductors (see Fig. 1)and the all
19、owable variation in conductor resistances if otherthan that specified in 6.2. Consult individual manufacturers forthe number of conductors which are limited by cable size.5.1.3 The sheath material (see 7.3) and whether it shall beseamless or welded and drawn. Note that other sheath materialmay be us
20、ed with purchaser and producer agreement.5.1.4 The nominal outside diameter of the sheath (see 6.3).5.1.5 The insulating material (either MgO or Al2O3) and itsrespective type (see 7.2). Note that other insulation composi-tion and impurity levels may be used with purchaser andproducer agreement.5.1.6
21、 The seal to be applied to the exposed insulation at thecable end(s) prior to shipment (see 11.1).5.1.7 Supplementary testing or material requirements (seeSupplementary Requirements).5.1.8 Any deviations from this specification or the refer-enced documents.5.1.9 The Optional Clearance if applicable
22、(see Fig. 1).6. General Requirements6.1 MIMS RTD CableCable shall be in accordance withthis specification (see Fig. 2). Fig. 2 shows a cable with twoconductors, but more than two conductors may be specified.6.2 Conductor Resistance MatchThe resistance of eachconductor shall be measured. The differen
23、ce between themaximum conductor resistance and minimum conductor resis-tance shall not exceed 10 % of the minimum conductorresistance.6.3 DimensionsThe dimensional and tolerance require-ments for sheath diameter and wall thickness, conductordiameter, and insulation thickness depicted in Fig. 2 andsu
24、mmarized in Table 1 shall be based on the nominal sheathoutside diameters. The purchaser need only specify the cablesoutside diameter and number of conductors required in theordering documents. The preferred cable sizes are listed inTable 2. For any nominal sheath size:6.3.1 The outside diameter tol
25、erance, A, shall be 0.001 in.(0.025 mm) or 6 1 % of the outside diameter, whichever isgreater.6.3.2 The wall thickness, B, shall be at least 8 % of thenominal sheath outside diameter and shall be uniform within1.6 % of the minimum sheath outside diameter.6.3.3 The conductor diameter, D, shall be at
26、least 8 % of thenominal sheath outside diameter.6.3.4 The insulation thickness, C, either between conductorsor between any conductor and the inside surface of the sheath,shall be at least 4 % of the nominal sheath outside diameter.6.3.5 An optional clearance “F” (see Figs. 1 and 2) may bespecified w
27、hen the area between the conductors will beremoved to make room for a sensing element. This construc-tion is one that is used when manufacturing Platinum Resis-tance Thermometers (PRTs) using this cable. Unless otherwisespecified, the other dimensional requirements shall be main-tained. Consult the
28、cable manufacturer regarding this optionalfeature.6.3.6 Dimensions shall be measured in accordance with TestMethods E839.6.4 MaterialsThe RTD cable shall be fabricated fromcomponent parts specified in Section 7.6.5 Insulation Resistance at Room TemperatureThe mini-mum insulation resistance between c
29、onductors and betweeneach conductor and the sheath (at room temperature) shall be as3Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.FIG. 1 Examples of Conductor Wire Configurations FIG. 2 Sheathed RTD Material Constructio
30、nE2821 132specified in Table 3 when tested in accordance with TestMethod E780 for the voltages noted. The values of insulationresistance, shall apply to the supplied lengths.6.6 Minimum Insulation DensityThe minimum density ofthe compacted mineral oxide insulation shall exceed the valuewhich represe
31、nts 70 % of the maximum theoretical density ofthe material. This 70 % value is 0.090 lb/in.3(2506 kg/m3) forMgO, and 0.101 lb/in.3(2780 kg/m3) for Al2O3.4See alsoSupplementary Requirement S5.6.7 Sheath ConditionThe sheath shall be free of visiblesurface contaminants and oxidation and shall be anneal
32、ed s tothe extent that the conductors will permit. Tests for provingconformance are in Supplementary Requirement S2 or S8.6.8 Sheath IntegrityThe sheath of the finished RTD cableshall exclude gases and liquids. There shall be no holes, cracks,or other void defects that penetrate through the sheath w
33、all.Tests for proving conformance to this requirement are inSupplementary Requirement S3.6.9 Additional optional supplementary requirements arelisted in the Supplementary Requirements section and may beincluded in the purchasing order requirements, if desired by thepurchaser.7. Material Requirements
34、7.1 Conductors:7.1.1 The conductors shall be solid, round wire of copper,nickel, nickel clad copper, or copper-45 % nickel (constantan)with maximum operating temperatures as specified in Table 4.7.1.2 All conductors used in a specific cable shall be fromthe same lot of material in order to minimize
35、the generation ofspurious Electromotive Forces (EMF) when placed in a tem-perature gradient.7.1.3 Prior to assembly, the producer shall verify all con-ductors used are free of visible surface oxides, scale andcontaminates such as drawing compounds, carbon, dirt anddust. The absence of scale and cont
36、aminants can be verified bywiping the wire with a solvent-saturated lint-free cloth.Acetone, isopropyl alcohol, methanol and ethanol are allacceptable solvents. A light discoloration of the cloth isacceptable unless particles of grit or metal flakes are visuallydetectable without use of magnificatio
37、n. If acetone or any othersolvent that may leave a residual film is used for initialcleaning, a final cleaning with an acceptable cleaning solvent,such as isopropyl alcohol, methanol or ethanol shall beperformed.7.2 Insulation:7.2.1 The insulation shall be magnesia (MgO) or alumina(Al2O3) conforming
38、 to Specification E1652.7.3 Sheath Material:7.3.1 The sheath material shall be austenitic stainless steel,or heat-resistant nickel-chrome alloy. If tubing is used, eitherseamless or welded is acceptable.7.3.2 A nickel-chrome-iron sheath, as in SpecificationsB163, B167,orB516, is recommended for fres
39、h water serviceand for applications with exposure to temperatures greater than896F (480C). There are high molybdenum stainless steelsthat are specifically made for use in salt water, such as type 316and proprietary alloys.7.3.3 Alternate heat-resistant tubing materials may be speci-fied for the shea
40、th by the producer provided the annealingrequirements imposed by 6.7 are satisfied.7.3.4 Prior to assembly, the producer shall verify that eachpiece of sheath material used in the fabrication of RTD cable isfree of visible surface oxides, scale and contaminants such asdrawing compounds, carbon, dirt
41、 and dust. The absence ofscale and contaminants can be verified by passing a solvent-saturated swatch of lint-free yarn or cloth against the innersurface of the sheath material. Acetone, isopropyl alcohol,methanol and ethanol are all acceptable solvents. A lightdiscoloration of the swatch or plug is
42、 acceptable unlessparticles of grit or metal flakes are visually detectable withoutthe use of magnification. If acetone or any other solvent thatleaves a harmful residual film upon evaporation is used for4Handbook of Chemistry and Physics, Chemical Rubber Publishing Co., No. 76(1995) edition.TABLE 1
43、 Summary of RTD Cable Dimensional Requirements(Percentage of Outside Diameter)2, 3, 4, 6, or 8 WiresMinimum Sheath Thickness “B” 8 %Minimum Conductor Diameter “D” 8 %Minimum Insulation Thickness “C” 4 %Optional Clearance “F” 25 %TABLE 2 Dimensions of Metal Sheathed RTD Cable in SI andInch-Pound Unit
44、sPreferred SizesNominal Outside Diameter “A”Millimetres Inches3.00 0.1254.50 0.1886.00 0.2508.00 0.3139.50 0.375TABLE 3 Room Temperature Insulation Resistance Requirementsin SI and Inch-Pound UnitsNominal SheathOutside DiameterApplied VoltageMinimum VDCInsulation Resistance(Megohms) MinimumLess than
45、 3.2 mm 500 50003.2 mm and larger 500 10 000Less than 125 in. 500 5000125 in. and larger 500 10 000TABLE 4 Recommended Maximum Conductor OperatingTemperaturesConductor Type C F SpecificationCopper 250 482 ASTM B286,UNS C11000,or UNS C01200Nickel CladCopper400 752 ASTM B366Nickel 201 650 1200 UNS N02
46、201Copper-45 %Nickel (Constantan)650 1200 ASTM B367Class 5UNS N04401E2821 133initial cleaning, a final cleaning with an acceptable cleaningsolvent such as isopropyl alcohol, methanol or ethanol shall beperformed.8. Processing Requirements8.1 The producer shall be responsible for raw materialsand all
47、 processing to ensure that the overall requirements ofthis specification are met.9. Quality Verification and Test Requirements9.1 The following tests are required for all MIMS RTDcable furnished under this specification:9.1.1 Dimensional inspection.9.1.2 Insulation resistance at room temperature.9.1
48、.3 Comparison of Conductor Resistances9.1.4 Dielectric Breakdown Test.9.2 DocumentationCertificate of conformance in accor-dance with Section 10.9.3 Optional testing is defined in the Supplementary Re-quirements section. If the purchaser desires that these tests beperformed in whole, or in part, the
49、y shall so state in thepurchasing documents.9.4 Standard TestsThe producer shall perform an inspec-tion and tests in accordance with Table 5, using the methodsdelineated in Test Methods E839. Sampling shall be performedfrom each lot.9.5 Dimensional InspectionThe producer shall measure asample of finished RTD cable to determine conformance to 6.3for the following: outside diameter, conductor diameter, sheathwall thickness, and insulation thickness. Dimensions shall bemeasured per Test Methods E839.9.6 Insulation Resistance at Room TemperatureThe insu-lation resis
