ASTM E1137 E1137M-2004 Standard Specification for Industrial Platinum Resistance Thermometers《工业用铂阻尼式温度计标准规范》.pdf

1、Designation: E 1137/E 1137M 04Standard Specification forIndustrial Platinum Resistance Thermometers1This standard is issued under the fixed designation E 1137/E 1137M; the number immediately following the designation indicates theyear of original adoption or, in the case of revision, the year of las

2、t revision. A number in parentheses indicates the year of lastreapproval. A superscript epsilon (e) 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 (PRTs)suitable

3、 for direct immersion temperature measurement. Itapplies to PRTs with an average temperature coefficient ofresistance between 0 and 100 C of 0.385 %/C and nominalresistance at 0 C of 100 V or other specified value. Thisspecification covers PRTs suitable for all or part of thetemperature range 200 to

4、 650 C. 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 or SI

5、(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 of the u

6、ser 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:3A 269 Specification for Seamless and Welded AusteniticStainless Steel Tubing for General ServiceB 167 Specific

7、ation for Nickel-Chromium-Iron Alloys(UNS N06600, N06601, N06603, N06690, N06693,N06025, and N06045) and Nickel-Chromium-Cobalt-Molybdenum Alloy (UNS N06617) Seamless Pipe andTubeE 344 Terminology Relating to Thermometry and Hydrom-etryE 644 Test Methods for Testing Industrial Resistance Ther-momete

8、rsE 1652 Specification for Magnesium Oxide and AluminumOxide Powder and Crushable Insulators Used in theManufacture of Metal-Sheathed Platinum Resistance Ther-mometers, Base Metal Thermocouples, and Noble MetalThermocouples3. Terminology3.1 DefinitionsFor definitions of terms used in this speci-fica

9、tion see Terminology E 344.3.2 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 to prevent the sensors insulation resistance fromdropping b

10、elow 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, nacceleration of an object relative to thelocal acceleration of grav

11、ity.3.2.4.1 DiscussionFor example, a g-level of 5 is equiva-lent to an acceleration of approximately 5 3 9.8 m/s2= 49.0m/s2.3.2.5 minimum immersion length, ndepth that a thermom-eter should be immersed, in a uniform temperature environ-ment, such that further immersion does not produce a change inin

12、dicated temperature greater than the specified tolerance.3.2.6 PRT design, ngeneric term used to differentiatebetween different PRT construction details, such as elementand connecting wire construction, insulation methods, sealingtechniques, and mounting methods (for example, spring loadedor direct

13、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 Aug. 1, 2004. Published August 2004. Originallyapproved in 1987. Last previous edition ap

14、proved in 1997 as E 1137 97.2Preston-Thomas, H., “The International Temperature Scale of 1990 (ITS-90),”Metrologia, Vol 27, No. 1, 1990, pp. 310. For errata see ibid, Vol 27, No. 2, 1990,p. 107.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at s

15、erviceastm.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.3.2.7 self-heating, nchange in temperature of the el

16、ementcaused 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 provide common termi-nology, resistance versus temperature characteristics,

17、accuracyclassification, and inspection requirements for a specifiedconfiguration of a typical industrial platinum resistance ther-mometer (PRT).4.2 This specification may be used as part of the documen-tation to support negotiations for the purchase and discussionof such thermometers.5. Classificati

18、on of Tolerances5.1 The PRT shall conform to the resistance-temperaturerelation (see 9.2.1) within the following tolerances:Grade A 560.13 1 0.0017|t|C (1)Grade B 560.25 1 0.0042|t|C (2)where:| t | = value of temperature without regard to sign, C.5.1.1 The tolerances are given in Table 1 for a PRT w

19、ith anominal resistance of 100 V at 0 C.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 Sheath diameter and overall length (see Fig. 1),6.1.3 Sheath material,6

20、.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),6.1.7 Tolerance, (Grade A, or Grade B),6.1.8 Nominal resistance at 0 C (

21、100 V 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 with thefollowing requirements:7.1.1 Sheath MaterialsFor temperature

22、s not exceeding480 C, austenitic stainless steel tubing, conforming to Speci-fication A 269. For temperatures not exceeding 650 C, high-nickel alloy tubing, conforming to Specification B 167.7.1.2 Sensing ElementSensing element shall be platinum.7.1.3 InsulationThe insulating material within the PRT

23、shall be compatible with the temperature range 200 C to 650C or as specified in 6.1.4. Magnesium oxide (MgO) andaluminum oxide (Al2O3) powders and crushable insulatorsconforming to Specification E 1652 satisfy this requirement.7.1.4 Connecting Wire End Closure MaterialsClosurematerials shall provide

24、 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 materials are used for ambienttemperatures less than 200 C and moistu

25、re impervious ce-ramic adhesives are used over 200 C, but the connecting wireend closure shall not be limited to these materials if the endclosure meets all other requirements of this specification.7.1.5 Connecting WiresTypically, materials of connectingwires are: nickel plated copper, nickel, plati

26、num, 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 materials are used, care mustbe exercised in their selection to mini

27、mize 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 withstand an external pressureof 21 MPa (3000 psig) and shall be

28、 tested in accordance withTest Methods E 644 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 E 644 using the test parameters in Table 2.8.2.2 The PRT shall be mounted by installation in

29、 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 monitored trace during the test.8.2.4 After the PRT is tested fo

30、r vibration the insulationresistance of the PRT shall remain within the tolerance of Table3 and the resistance at 0 C within the tolerance specified in5.1.8.3 Mechanical Shock:8.3.1 The PRT shall withstand mechanical shock testing asdescribed in Test Methods E 644. The half-sine pulse shallhave a pe

31、ak g-level of 50 and duration of 11 ms.TABLE 1 Classification TolerancesA, BTemperature, t,CGrade A Grade BC V C V 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 0.53400 0.81 0.28 1.9 0.66500 0.98 0.33 2.4 0.78600 1.1

32、5 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 V (nominal) at 0 C.E 1137/E 1137M 0428.3.2 The PRT shall be co

33、ntinuously 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 within thetolerance of Table 3 and the resistance at 0 C

34、 within thetolerance in 5.1.8.4 Thermal:8.4.1 The PRT shall 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 operating tem-perature range. As a minimum, these materi

35、als 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 effects shall be considered.9.1.2 The PRT shall be capable

36、 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 EquationsWithin the speci-fied tolerances (see 5.1), the PR

37、T shall have resistance-temperature characteristics defined as follows:for the range 200 C # t 0 C:Rt5 Ro1 1 At 1 Bt21 Ct 2 100!t3# V (3)for the range 0 C # t # 650 C:Rt5 Ro1 1 At 1 Bt2# V (4)where:FIG. 1 Typical Industrial Platinum Resistance ThermometerFIG. 2 Connection ConfigurationsTABLE 2 Vibra

38、tion 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 unsupported stem length less than 100 mm (4 in.).Frequency 5

39、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 As normally mounted including the mating thermowell,if app

40、licable.TABLE 3 Insulation ResistanceApplied dc Voltage, Volts dc Minimum Insulation Resistancemin max C MV10 50 25 6 5 10010 50 300 6 10 1010 50 650 6 15 2E 1137/E 1137M 043t = temperature (ITS-90), C,Rt= resistance at temperature (t),Ro= resistance at 0 C,A = 3.9083 3 103C1,B = 5.775 3 107C-2, and

41、C = 4.183 3 1012C4.9.2.2 Resistance TableResistance values of the PRT ver-sus temperature using the equations of 9.2.1 and Roof 100 Vare 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 X1.9.3 Insulation Re

42、sistanceThe insulation resistance be-tween each connecting wire and the sheath shall meet therequirements of Table 3 when tested in accordance with TestMethods E 644. The PRT shall be tested with at least theminimum immersion length exposed to the temperature envi-ronment.9.4 Self-HeatingA power of

43、at least 33 mW shall berequired to produce a self-heating of 1 C when the PRT istested in water in accordance with Test Methods E 644.9.5 Thermal Response TimeThe 63.2 % response timeshall not exceed the values in Table 5 when determined inaccordance with Test Methods E 644. The step change intemper

44、ature shall be from 20 6 5 C air to 77 6 5 C 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 E 644 at the upper operating temperature, thePRT shall remain within the tolerances specified in 5.1 with anexcitation current of 1-mA dc

45、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 thisthermoel

46、ectric 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 with Test

47、Meth-ods E 644, the PRT shall remain within the tolerances specifiedin 5.1 for a four-week test. During this test, the resistance at 0C shall be checked at regular intervals (two times per week).9.8 Minimum Immersion LengthWhen determined in ac-cordance with Test Methods E 644, the PRT minimum immer

48、-sion length shall be less than 51 mm (2 in.). The limit ofuncertainty shall be 0.13 C and 0.25 C for Grade A and GradeB PRTs respectively.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 acc

49、ordance with this specifica-tion shall be able to pass through the straightness ring gagewith the gage 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 manufacturer shall perform these tests atleast one time to qualify the PRT design. Thereafter, it isrecommended these tests be used on a periodic basis to verifyprocess control.11.1.1 Qualification Test ReportThe