1、Designation: D8164 18Standard Guide forDigital Contact Thermometers for Petroleum Products,Liquid Fuels, and Lubricant Testing1This standard is issued under the fixed designation D8164; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revisio
2、n, 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 guide establishes criteria for the various parametersneeded to define a digital contact thermomete
3、r (DCT) suitablefor measuring temperature in the test methods utilized byCommittee D02. The DCT criteria are based on the design andsensing characteristics of the liquid-in-glass thermometers thathave been used successfully in Committee D02 test methods.1.2 The values stated in SI units are to be re
4、garded asstandard. No other units of measurement are included in thisstandard.1.3 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, health, and environmental pra
5、ctices and deter-mine the applicability of regulatory limitations prior to use.1.4 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides a
6、nd Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D97 Test Method for Pour Point of Petroleum ProductsD445 Test Method for Kinematic Viscosity of Transparentand Opaque Liquids (and Calculation of Dynamic V
7、iscos-ity)D2162 Practice for Basic Calibration of Master Viscometersand Viscosity Oil StandardsD2386 Test Method for Freezing Point of Aviation FuelsD2500 Test Method for Cloud Point of Petroleum Productsand Liquid FuelsD2532 Test Method for Viscosity and Viscosity ChangeAfter Standing at Low Temper
8、ature of Aircraft TurbineLubricantsD2983 Test Method for Low-Temperature Viscosity of Au-tomatic Transmission Fluids, Hydraulic Fluids, and Lubri-cants using a Rotational ViscometerD3829 Test Method for Predicting the Borderline PumpingTemperature of Engine OilD4539 Test Method for Filterability of
9、Diesel Fuels byLow-Temperature Flow Test (LTFT)D4684 Test Method for Determination of Yield Stress andApparent Viscosity of Engine Oils at Low TemperatureD5853 Test Method for Pour Point of Crude OilsD6371 Test Method for Cold Filter Plugging Point of Dieseland Heating FuelsD6821 Test Method for Low
10、 Temperature Viscosity of DriveLine Lubricants in a Constant Shear Stress ViscometerD6896 Test Method for Determination of Yield Stress andApparent Viscosity of Used Engine Oils at Low Tempera-tureD7279 Test Method for Kinematic Viscosity of Transparentand Opaque Liquids by Automated Houillon Viscom
11、eterD7962 Practice for Determination of Minimum ImmersionDepth and Assessment of Temperature Sensor Measure-ment DriftE1 Specification for ASTM Liquid-in-Glass ThermometersE563 Practice for Preparation and Use of an Ice-Point Bathas a Reference TemperatureE644 Test Methods for Testing Industrial Res
12、istance Ther-mometersE1750 Guide for Use of Water Triple Point CellsE2251 Specification for Liquid-in-Glass ASTM Thermom-eters with Low-Hazard Precision LiquidsE2877 Guide for Digital Contact Thermometers2.2 ISO Standard:3ISO 17025 General requirements for the competence oftesting and calibration la
13、boratories1This guide is under the jurisdiction of ASTM Committee D02 on PetroleumProducts, Liquid Fuels, and Lubricants and is the direct responsibility of Subcom-mittee D02.91 on Coordinating Subcommittee on Thermometry.Current edition approved April 1, 2018. Published April 2018. DOI: 10.1520/D81
14、64-18.2For 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.3Available from American National Standards Institute (
15、ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardizati
16、on established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.13. Terminology3.1 Definitions:3.1.1 digital contact thermometer (DCT), nan electronicdevice consi
17、sting of a digital display and associated tempera-ture sensing probe.3.1.1.1 DiscussionThis device consists of a temperaturesensor connected to a measuring instrument; this instrumentmeasures the temperature-dependent quantity of the sensor,computes the temperature from the measured quantity, andpro
18、vides a digital output. This digital output goes to a digitaldisplay and/or recording device that may be internal or externalto the device.3.1.1.2 DiscussionThe devices are often referred to as a“digital thermometer,” however the term includes devices thatsense temperature by means other than being
19、in physicalcontact with the media.3.1.1.3 DiscussionPET is an acronym for portable elec-tronic thermometers, a subset of digital contact thermometers(DCT).3.1.2 immersion depth, ndepth that a thermometer shouldbe immersed in a uniform temperature environment, such thatfurther immersion does not prod
20、uce a change in indicatedtemperature greater than the specified tolerance.4. Summary of Guide4.1 This guide provides the criteria for several digitalcontact thermometers (DCT). The DCT criteria were selectedso that the temperature measured by a DCT would be expectedto be essentially the same as that
21、 measured by a LiG thermom-eter. These criteria focus on temperature measurement inCommittee D02 test methods or similar measurement situa-tions. In many D02 test methods, the temperature of a smallstatic sample volume is being made thus the difference betweendevice thermal conductivity will have a
22、large impact onequivalent measurements. It is the responsibility of the stan-dard developer and user to ensure that a specific DCT criteriawill adequately replace a cited liquid-in-glass thermometer.4.2 The DCT temperature sensing elements used in thisguide are platinum resistance temperature (PRT)
23、detector,thermistor or thermocouple which are in contact with thesubstance thus referred to as a digital contact thermometer.Both PRTs and thermistors are members of a group referred toas resistance temperature detectors (RTD) as their resistance isa function of temperature. Thermocouples are create
24、d bylinking two dissimilar metals which results in a temperaturedependent potential.5. Significance and Use5.1 The DCT criteria listed in Table 1 have been found to besuitable for replacing some of the noted liquid-in-glass ther-mometers with a DCT. The criteria stated are based on theliquid-in-glas
25、s (LiG) thermometer design which are the bulblength, immersion depth, precision of measurement, thermom-eter position, etc. The parameters for sensor length, immersiondepth, sheath diameter are especially critical when measuringthe temperature of small static samples due to temperatureprobe thermal
26、conductivity. A DCT that is suitable for use in astirred constant temperature bath will likely result in measure-ment errors when used to measure small sample temperature.These can be a degree or more when the sample temperaturediffers from room temperature by 40 C or more usinga7mmprobe. This error
27、 is due to the difference in thermal conduc-tivity of a DCT and LiG thermometer. The most effective wayto counter this is by reducing DCT sheath diameter, insulatingthe sheath above the immersion level, and using a probe thathas a small immersion depth as determined by Practice D7962.5.2 When replac
28、ing a LiG thermometer with one of theD02-DCTs listed in Table 1 and the test method does not listany DCT criteria, it is incumbent on the user to verify thesuitability of the DCT they have selected. This can be done bycomparing measurements made with the selected DCT to thoseof a LiG thermometer and
29、 following the test procedure.Comparative measurements are especially important whenmeasuring the temperature of a small static sample where thereis a large difference between sample and room temperature.6. DCT Criteria6.1 The DCT criteria shown in Table 1 are for varioustemperature measurement appl
30、ications used in Committee D02test methods.NOTE 1The DCTs electronics are typically limited to an environmentof 0 C to 35 C. A DCTs temperature limits can be found in its manualor in the manufacturers specifications.6.2 Probe Immersion DepthThis criteria quantifies thedistance from the DCT probe tip
31、 that should be covered by thematerial being measured in order to obtain an accurate tem-perature measurement. Immersing the probe in a material byless than its minimum immersion depth can result in tempera-ture measurements that differ from actual temperature. Theerror is dependent on the temperatu
32、re difference between thematerial being measured and surrounding (ambient) tempera-ture. Immersions greater than this immersion depth are accept-able.6.3 Measurement DriftThe drift in calibration should bechecked periodically and at least once per year. This can beaccomplished using Practice D7962 o
33、r Test Methods E644.When a DCTs calibration drifts in one direction over severalcalibration checks against a reference temperature, such as theice point, it may be an indication of deterioration of the DCT.The probe is to be recalibrated, when the check value differs bymore than the calibration drif
34、t listed in Table 1 from the lastprobe calibration. See Practice E563, Test Methods E644,orGuide E1750 for more information regarding checking cali-brations.NOTE 2For reference temperatures, additional information on prepar-ing and using an ice bath can be found in Practice E563. Guide E1750provides
35、 guidance for preparing and using a water triple point cell.6.4 Response Timeis the time it takes a DCT probe(sensor) to respond to a step change in temperature. This isdefined as 63.2 % of the time it takes a DCT to fully respondto a step change in temperature. The test is done according toSection
36、9 of Test Methods E644 where the step change beginswith the DCT at an initial temperature of 20 C 6 5 C airbefore transferring to water at 77 C 6 5 C with it flowing at0.9 m s 6 0.09 m s past the sensor.D8164 1826.5 CalibrationThe calibration temperature data shouldbe evenly distributed over a devic
37、es nominal temperaturerange (Table 1) or over the range of use if narrower than thenominal temperature range. The calibration data should beincluded in calibration report. The calibration report should beobtained from a calibration laboratory with demonstratedcompetency in temperature calibration wh
38、ich is traceable to anational calibration laboratory or metrology standards body.An example is a calibration laboratory with a ISO 17025accreditation that includes temperature calibration.6.6 ThermowellsWhen inserting a DCT probe into athermowell with a larger diameter, a sleeve is needed to ensureg
39、ood thermal transfer from the wall to the DCT sheath. Thissleeve is to be made from a thermally conductive substancesuch as metal such as copper, brass, bronze, aluminum, steel, orother material.6.7 A DCT Certification/Calibration report may differ froma liquid-in-glass thermometer since a system ad
40、justment canallow readings to be closely matched to the reference at the testpoint values. If system adjustments can not be made then thereport needs to include the correction factors needed to bringthe display temperature to the correct value along with guid-ance on applying them. A report may show
41、 AS FOUND valuesthat were documented before adjustments, andAS LEFT whichare the values documented after adjustments may have beenmade.ADCTs accuracy (tolerance) as shown in its calibrationreport is to be consistent with those listed for its “E2877Class”.7. DCT Citation7.1 The DCT citation referenci
42、ng these criteria in a standardshould include the D02-DCT designation, any variance fromthe criteria in Table 1, and include the information in subsec-tions 6.2 through 6.5.8. Keywords8.1 DCT; digital contact thermometers; LiG; liquid-in-glassthermometersD8164 183TABLE 1 DCT Criteria for D02 Test Me
43、thodsNOTE 1When making measurements below 40 C with a PRT, it may be necessary to use a 1000 PRT sensor in order to obtain accuratemeasurements.NOTE 2Additional information on PRT sensors and their testing can be found in Test Methods E644.D02DCT ID D02-DCT01 D02-DCT02 D02-DCT03 D02-DCT04E1 and E225
44、1 listed LiGThermometers5C, S5C(High Cloud and Pour)61C(Melt Point)6C(Low Cloud and Pour)43C, 72C, 73C, 74C, 114C,122C, 123C, 124C, 125C,126C, 127C, 128CPotential Application D97, D2500, D5853 D97, D5853 D97, D2500, D5853 D445Temperature sensor placementASample Sample Sample Temperature bathParamete
45、r DCT CriteriaE2877 Class, minimum F F F ANominal temperature range,BC 38 to 50 32 to 127 80 to 20 80 to 20Display resolution, C minimum 0.1 0.1 0.1 0.01Accuracy,CC minimum 0.5 0.5 0.5 0.05Sensor type (Note 1 and Note 2) PRT, Thermistor PRT, Thermistor PRT, Thermistor PRTSensor sheath,Dmax diameter,
46、 mm 4.2E4.2 4.2E7Sensor length,Fmax mm 10 10 10 45Probe immersion depth by D7962,Gmm(see 6.2)40 40 40 105Measurement drift,Hless than C(see 6.3)0.5 0.5 0.5 0.01Response time,Iless thanor equal to, seconds (see 6.4)44 4 8Calibration data,Jminimum(see 6.5)4AIndicates placement of the sensor which is t
47、ypically in the sample or the container (bath) holding the sample.BA devices minimum and maximum temperature may be different than the values shown provided the calibration requirements are met.CAccuracy is the combined accuracy of the DCT unit that is the display and sensor without correction facto
48、rs.DSensor sheath is the tube that holds the sensing element. The value is the nominal outside diameter of the sheath segment containing the sensing element.ESupporting data have been filed at ASTM international headquarters and may be obtained by requesting research report RR:D02-1849.FThe physical
49、 length of the temperature sensing element. Contact the DCT supplier to determine whether this parameter is met, as it will not be accessible to the user.GMinimum probe immersion depth needed for an accurate measurement as determined by Practice D7962 and is to be equal to or less than the value in the table.HAs determined by Practice D7962 or an equivalent procedure.IResponse time determined per 6.4 following procedure in Test Methods E644, Section 9.JMinimum number of calibration data points used to establish calibration, subsection 6.4.K
