1、Designation: E1137/E1137M 08 (Reapproved 2014)Standard Specification forIndustrial Platinum Resistance Thermometers1This standard is issued under the fixed designation E1137/E1137M; the number immediately following the designation indicates the yearof original adoption or, in the case of revision, t
2、he year of last revision. A number in parentheses indicates the year of last reapproval.A superscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This specification covers the requirements for metal-sheathed industrial platinum resistance thermometers (
3、PRTs)suitable for direct immersion temperature measurement. Itapplies to PRTs with an average temperature coefficient ofresistance between 0 and 100C of 0.385 %C and nominalresistance at 0C of 100 or other specified value. Thisspecification covers PRTs suitable for all or part of thetemperature rang
4、e 200 to 650C. The resistance-temperaturerelationship and tolerances are specified as well as physical,performance, and testing requirements.1.2 The values of temperature in this specification are basedon the International Temperature Scale of 1990 (ITS-90).21.3 The values stated in inch-pound units
5、 or SI (metric)units may be regarded separately as standard. The values statedin each system are not exact equivalents, and each system shallbe independent of the other.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility o
6、f 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. Referenced Documents2.1 ASTM Standards:3A269 Specification for Seamless and Welded AusteniticStainless Steel Tubing for General ServiceB167 Spe
7、cification 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 TubeE344 Terminology Relating to Thermometry and Hydrom-etryE
8、644 Test Methods for Testing Industrial Resistance Ther-mometersE1652 Specification for Magnesium Oxide and AluminumOxide Powder and Crushable Insulators Used in theManufacture of Base Metal Thermocouples, Metal-Sheathed Platinum Resistance Thermometers, and NobleMetal Thermocouples3. Terminology3.1
9、 DefinitionsFor definitions of terms used in this speci-fication see Terminology E344.3.2 Definitions of Terms Specific to This Standard:3.2.1 connecting wire end closure, nmoisture barrier atthe connecting wire end of the sheath.3.2.1.1 DiscussionThe closure is intended to provide aseal sufficient
10、to prevent the sensors insulation resistance fromdropping below the minimum requirements.3.2.2 connecting wires, nwires that run from the elementthrough the connecting wire end closure and external to thesheath.3.2.3 excitation, nelectrical current passing through theelement.3.2.4 g-level, naccelera
11、tion of an object relative to thelocal acceleration of gravity.3.2.4.1 DiscussionFor example, a g-level of 5 is equiva-lent to an acceleration of approximately 5 9.8 m/s2= 49.0m/s2.3.2.5 minimum immersion length, ndepth that a thermom-eter should be immersed, in a uniform temperatureenvironment, suc
12、h that further immersion does not produce achange in indicated temperature greater than the specifiedtolerance.3.2.6 PRT design, ngeneric term used to differentiatebetween different PRT construction details, such as elementand connecting wire construction, insulation methods, sealingtechniques, and
13、mounting methods (for example, spring loadedor direct mounting).1This 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 Dec. 1, 2014. Published December 20
14、14. Originallyapproved in 1987. Last previous edition approved in 2008 as E1137 08. DOI:10.1520/E1137_E1137M-08R14.2Preston-Thomas, H., “The International Temperature Scale of 1990 (ITS-90),”Metrologia , Vol 27, No. 1. 1990, pp 3 10, ibid, Vol 27, No. 2, 1990, p1073For referenced ASTM standards, vis
15、it 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 International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-29
16、59. United States13.2.7 self-heating, nchange in temperature of the elementcaused by the heating effect of the excitation.3.2.8 sheath, ncylindrical metal tube with an integralwelded closure at the end in which the element is located.4. Significance and Use4.1 This specification is written to provid
17、e commonterminology, resistance versus temperature characteristics, ac-curacy classification, and inspection requirements for a speci-fied configuration of a typical industrial platinum resistancethermometer (PRT).4.2 This specification may be used as part of the documen-tation to support negotiatio
18、ns for the purchase and discussionof such thermometers.5. Classification of Tolerances5.1 The PRT shall conform to the resistance-temperaturerelation (see 9.2.1) within the following tolerances:Grade A 560.1310.0017? t ? #C (1)Grade B 560.2510.0042 ? t ? #C (2)where:| t | = value of temperature with
19、out regard to sign, C.5.1.1 The tolerances are given in Table 1 for a PRT with anominal resistance of 100 at 0C.6. Ordering Information6.1 The purchase order documents shall specify the follow-ing information to ensure that the PRT is adequately described:6.1.1 The number of this specification,6.1.2
20、 Sheath diameter and overall length (see Fig. 1),6.1.3 Sheath material,6.1.4 Minimum and maximum sensed temperature,6.1.5 Maximum and minimum temperature at connectingwire end closure,6.1.6 Connection configuration; 2-Wire, 3-Wire, 4-Wire(potentiometric), and compensating loop (4-Wire) (see Fig. 2),
21、6.1.7 Tolerance, (Grade A, or Grade B),6.1.8 Nominal resistance at 0C (100 unless otherwisespecified), and6.1.9 Serial Number identification requirement (mandatoryif an individual calibration or test record will be maintained).7. Materials and Manufacture7.1 All materials used shall be in accordance
22、 with thefollowing requirements:7.1.1 Sheath MaterialsFor temperatures not exceeding480C, austenitic stainless steel tubing, conforming to Speci-fication A269. For temperatures not exceeding 650C, high-nickel alloy tubing, conforming to Specification B167.7.1.2 Sensing ElementSensing element shall b
23、e platinum.7.1.3 InsulationThe insulating material within the PRTshall be compatible with the temperature range 200 to 650Cor as specified in 6.1.4. Magnesium oxide (MgO) and alumi-num oxide (Al2O3) powders and crushable insulators conform-ing to Specification E1652 satisfy this requirement.7.1.4 Co
24、nnecting Wire End Closure MaterialsClosurematerials shall provide a barrier against water and other liquidsand generally prevent the penetration of water vapor. Anymaterial used shall be compatible with the ambient tempera-tures specified for the application (see 6.1.5).7.1.4.1 Typically, epoxy mate
25、rials are used for ambienttemperatures less than 200C and moisture impervious ceramicadhesives are used over 200C, but the connecting wire endclosure shall not be limited to these materials if the end closuremeets all other requirements of this specification.7.1.5 Connecting WiresTypically, material
26、s of connectingwires are: nickel plated copper, nickel, platinum, constantan, ormanganin. Individual connecting wires may be comprised oftwo or more different materials and sizes over their length toaccommodate different requirements internal and external tothe sensor sheath.Where different material
27、s are used, care mustbe exercised in their selection to minimize thermoelectricallyinduced measurement error (see 9.6). Any material used injoining the connecting wires to the PRT element must with-stand the maximum operating temperature of the PRT.8. Other Requirements8.1 PressureThe PRT shall with
28、stand an external pressureof 21 MPa (3000 psig) and shall be tested in accordance withTest Methods E644 pressure test. The PRT shall remain withinthe tolerance specified in 5.1.8.2 Vibration:8.2.1 The PRT shall withstand vibration testing as describedin Test Methods E644 using the test parameters in
29、 Table 2.8.2.2 The PRT shall be mounted by installation in thethermowell or by threaded connection to simulate normalmounting procedure as limited by Table 2.8.2.3 The PRT shall be continuously energized with anoscilloscope-monitored 1.0-mA dc excitation. There shall beno discontinuity of the monito
30、red trace during the test.8.2.4 After the PRT is tested for vibration the insulationresistance of the PRT shall remain within the tolerance of Table3 and the resistance at 0C within the tolerance specified in 5.1.8.3 Mechanical Shock:8.3.1 The PRT shall withstand mechanical shock testing asdescribed
31、 in Test Methods E644. The half-sine pulse shall havea peak g-level of 50 and duration of 11 ms.TABLE 1 Classification TolerancesA, BTemperature, t,CGrade A Grade BC C 200 0.47 0.20 1.1 0.47 100 0.30 0.12 0.67 0.270 0.13 0.05 0.25 0.10100 0.30 0.11 0.67 0.25200 0.47 0.17 1.1 0.40300 0.64 0.23 1.5 0.
32、53400 0.81 0.28 1.9 0.66500 0.98 0.33 2.4 0.78600 1.15 0.37 2.8 0.89650 1.24 0.40 3.0 0.94AThe table represents values for 3-wire and 4-wire PRTs. Caution must beexercised with 2-wire PRTs because of possible errors caused by connectingwires.BTabulated values are based on elements of 100.0 (nominal)
33、 at 0C.E1137/E1137M 08 (2014)28.3.2 The PRT shall be continuously energized with anoscilloscope-monitored 1.0-mA dc excitation. There shall beno discontinuity of the monitored trace during the test.8.3.3 After the PRT is tested for mechanical shock, theinsulation resistance of the PRT shall remain w
34、ithin thetolerance of Table 3 and the resistance at 0C within thetolerance in 5.1.8.4 Thermal:8.4.1 The PRTshall be capable of continuous operation overthe specified temperature range (see 6.1).8.4.2 The connecting wire end closure and external connect-ing wires need not withstand the entire PRT ope
35、rating tem-perature range. As a minimum, these materials must withstandthe ambient temperature limits specified for the application(see 6.1.5).9. Performance9.1 Excitation:9.1.1 The PRT must be constructed such that it is usable inac or dc measurement systems. In ac measuring systems,reactance effec
36、ts shall be considered.9.1.2 The PRTshall be capable of operating with continuousexcitation of 10 mA. However, excitation of 1 mA or less isrecommended to minimize measurement errors associated withself-heating (see 9.4).9.2 Resistance versus Temperature Relation:9.2.1 Resistance-Temperature Equatio
37、nsWithin the speci-fied tolerances (see 5.1), the PRT shall have resistance-temperature characteristics defined as follows:for the range 200C t 0C:Rt5 Ro11At1Bt21Ct 2 100!t3# (3)for the range 0C t 650C:Rt5 Ro11At1Bt2# (4)where:t = temperature (ITS-90), C,FIG. 1 Typical Industrial Platinum Resistance
38、 ThermometerFIG. 2 Connection ConfigurationsTABLE 2 Vibration Test ParametersNOTE 1 The values in Table 2 apply to a PRT mounted in athermowell with nominal diametral clearance of less than 0.25 mm (0.01in.). If the PRT is not mounted in a thermowell, the values in Table 2 applyto a PRT with an unsu
39、pported stem length less than 100 mm (4 in.).Frequency 5 to 500 HzTest Level 1.27-mm (0.05-in.) double amplitude displacement orpeak g-level of 3, whichever is lessResonant Dwell Time 30 min for each resonant pointCycling Time 3 h per axis less the time spent at resonant dwells atthe axis.Mounting A
40、s normally mounted including the mating thermowell,if applicable.TABLE 3 Insulation ResistanceApplied dc Voltage, Volts dc Minimum Insulation Resistancemin max C M10 50 25 5 10010 50 300 10 1010 50 650 15 2E1137/E1137M 08 (2014)3Rt= resistance at temperature (t),Ro= resistance at 0C,A = 3.9083 103C1
41、,B = 5.775 107C2, andC = 4.183 1012C4.9.2.2 Resistance TableResistance values of the PRT ver-sus temperature using the equations of 9.2.1 and Roof 100 are given in Table 4.9.2.3 Inverse equations that may be used to compute valuesof temperature (C) as a function of resistance are given inAppendix X1
42、.9.3 Insulation ResistanceThe insulation resistance be-tween each connecting wire and the sheath shall meet therequirements of Table 3 when tested in accordance with TestMethods E644. The PRT shall be tested with at least theminimum immersion length exposed to the temperature envi-ronment.9.4 Self-H
43、eatingA power of at least 33 mW shall berequired to produce a self-heating of 1C when the PRT istested in water in accordance with Test Methods E644.9.5 Thermal Response TimeThe 63.2 % response timeshall not exceed the values in Table 5 when determined inaccordance with Test Methods E644. The step c
44、hange intemperature shall be from 20 6 5C air to 77 6 5C waterflowing at 0.9 6 0.09 m/s (3.0 6 0.3 ft/s).9.6 Thermoelectric Effect When tested in accordance withTest Methods E644 at the upper operating temperature, thePRT shall remain within the tolerances specified in 5.1 with anexcitation current
45、of 1-mA dc 6 15 %, regardless of polarity.NOTE 1Internal and external connecting wire composition, wireinhomogeneity, and temperature gradients within the PRT can be sourcesfor generation of thermoelectric EMF. Some resistance determinationerror can result from this EMF. The magnitude and sense of t
46、histhermoelectric effect error depends on the excitation current, temperaturedistribution, and construction of the PRT. For a given PRT, the thermo-electric effect can be minimized by using an alternating polarity excitationwith a suitable measurement circuitry.9.7 StabilityWhen tested in accordance
47、 with Test MethodsE644, the PRT shall remain within the tolerances specified in5.1 for a four-week test. During this test, the resistance at 0Cshall be checked at regular intervals (two times per week).9.8 Minimum Immersion LengthWhen determined in ac-cordance with Test Methods E644, the PRT minimum
48、 immer-sion length shall be less than 51 mm (2 in.). The limit ofuncertainty shall be 0.13 and 0.25C for Grade A and Grade BPRTs respectively.9.9 End Seal IntegrityWhen tested in accordance withTest Methods E644, the PRT shall meet the minimum insula-tion resistance value at 25 6 5C as specified in
49、Table 3.10. Dimensions, Mass, and Permissible Variations10.1 A PRT without a process fitting or other means ofattachment is shown in Fig. 1.10.2 PRTs manufactured in accordance with this specifica-tion shall be able to pass through the straightness ring gaugewith the gauge sizes listed in Table 6.11. Required Tests11.1 Qualification TestsThe PRT shall be subjected to thetests outlined in Table 7 to demonstrate conformance to thisspecification. The man
