1、Designation: D8164 18D8164 18aStandard 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 o
2、f 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. Scope Scope*1.1 This guide establishes criteria for the various parameters needed to define a digital c
3、ontact thermometer (DCT) suitable formeasuring temperature in the test methods utilized by Committee D02. The DCT criteria are based on the design and sensingcharacteristics of the liquid-in-glass thermometers that have been used successfully in Committee D02 test methods.1.2 The values stated in SI
4、 units are to be regarded as standard. No other units of measurement are included in this standard.1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety, health,
5、and environmental practices and determine the applicability ofregulatory limitations prior to use.1.4 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International St
6、andards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers 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 Transparent and Opaque Liquids (and Calcula
7、tion of Dynamic Viscosity)D2162 Practice for Basic Calibration of Master Viscometers and Viscosity Oil StandardsD2386 Test Method for Freezing Point of Aviation FuelsD2500 Test Method for Cloud Point of Petroleum Products and Liquid FuelsD2532 Test Method for Viscosity and Viscosity Change After Sta
8、nding at Low Temperature of Aircraft Turbine LubricantsD2983 Test Method for Low-Temperature Viscosity of Automatic Transmission Fluids, Hydraulic Fluids, and Lubricants usinga Rotational ViscometerD3829 Test Method for Predicting the Borderline Pumping Temperature of Engine OilD4539 Test Method for
9、 Filterability of Diesel Fuels by Low-Temperature Flow Test (LTFT)D4684 Test Method for Determination of Yield Stress and Apparent Viscosity of Engine Oils at Low TemperatureD5853 Test Method for Pour Point of Crude OilsD6371 Test Method for Cold Filter Plugging Point of Diesel and Heating FuelsD682
10、1 Test Method for Low Temperature Viscosity of Drive Line Lubricants in a Constant Shear Stress ViscometerD6896 Test Method for Determination of Yield Stress and Apparent Viscosity of Used Engine Oils at Low TemperatureD7279 Test Method for Kinematic Viscosity of Transparent and Opaque Liquids by Au
11、tomated Houillon ViscometerD7962 Practice for Determination of Minimum Immersion Depth and Assessment of Temperature Sensor Measurement DriftE1 Specification for ASTM Liquid-in-Glass ThermometersE563 Practice for Preparation and Use of an Ice-Point Bath as a Reference TemperatureE644 Test Methods fo
12、r Testing Industrial Resistance ThermometersE1750 Guide for Use of Water Triple Point CellsE2251 Specification for Liquid-in-Glass ASTM Thermometers with Low-Hazard Precision Liquids1 This guide is under the jurisdiction of ASTM Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants and i
13、s the direct responsibility of SubcommitteeD02.91 on Coordinating Subcommittee on Thermometry.Current edition approved April 1, 2018July 1, 2018. Published April 2018August 2018. Last previous edition approved in 2018 as D8164 18. DOI: 10.1520/D8164-18.10.1520/D8164-18A.2 For referencedASTM standard
14、s, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM
15、standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by
16、 ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1E2877 Guide for Digital Contact Thermometers2.2 ISO Standard:3ISO 17025 G
17、eneral requirements for the competence of testing and calibration laboratories3 Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http:/www.ansi.org.D8164 18a23. Terminology3.1 Definitions:3.1.1 digital contact thermometer (DCT), nan electron
18、ic device consisting of a digital display and associated temperaturesensing probe.3.1.1.1 DiscussionThis device consists of a temperature sensor connected to a measuring instrument; this instrument measures the temperature-dependent quantity of the sensor, computes the temperature from the measured
19、quantity, and provides a digital output. This digitaloutput goes to a digital display and/or recording device that may be internal or external to the device.3.1.1.2 DiscussionThe devices are often referred to as a “digital thermometer,”thermometers,” however the term includes devices that sensetempe
20、rature by means other than being in physical contact with the media.3.1.1.3 DiscussionPET is an acronym for portable electronic thermometers, a subset of digital contact thermometers (DCT).3.1.2 immersion depth, ndepth that a thermometer should be immersed in a uniform temperature environment, such
21、thatfurther immersion does not produce a change in indicated temperature greater than the specified tolerance.4. Summary of Guide4.1 This guide provides the criteria for several digital contact thermometers (DCT). The DCT criteria were selected so that thetemperature measured by a DCT would be expec
22、ted to be essentially the same as that measured by a LiG thermometer. Thesecriteria focus on temperature measurement in Committee D02 test methods or similar measurement situations. In many D02 testmethods, the temperature of a small static sample volume is being made thus the difference between dev
23、ice thermal conductivitywill have a large impact on equivalent measurements. It is the responsibility of the standard developer and user to ensure that aspecific DCT criteria will adequately replace a cited liquid-in-glass thermometer.4.2 The DCT temperature sensing elements used in this guide are p
24、latinum resistance temperature (PRT) detector, thermistoror thermocouple which are in contact with the substance thus referred to as a digital contact thermometer. Both PRTs andthermistors are members of a group referred to as resistance temperature detectors (RTD) as their resistance is a function
25、oftemperature. Thermocouples are created by linking two dissimilar metals which results in a temperature dependent potential.5. Significance and Use5.1 The DCT criteria listed in Table 1 have been found to be suitable for replacing some of the noted liquid-in-glassthermometers with a DCT. The criter
26、ia stated are based on the liquid-in-glass (LiG) thermometer design which are the bulb length,immersion depth, precision of measurement, thermometer position, etc. and so forth. The parameters for sensor length, immersiondepth, sheath diameter are especially critical when measuring the temperature o
27、f small static samples due to temperature probethermal conductivity. A DCT that is suitable for use in a stirred constant temperature bath will likely result in measurement errorswhen used to measure small sample temperature. These can be a degree or more when the sample temperature differs from roo
28、mtemperature by 40 C or more using a 7 mm probe. This error is due to the difference in thermal conductivity of a DCT and LiGthermometer. The most effective way to counter this is by reducing DCT sheath diameter, insulating the sheath above theimmersion level, and using a probe that has a small imme
29、rsion depth as determined by Practice D7962.5.2 When replacing a LiG thermometer with one of the D02-DCTs listed in Table 1 and the test method does not list any DCTcriteria, it is incumbent on the user to verify the suitability of the DCT they have selected. This can be done by comparingmeasurement
30、s made with the selected DCT to those of a LiG thermometer and following the test procedure. Comparativemeasurements are especially important when measuring the temperature of a small static sample where there is a large differencebetween sample and room temperature. Covering the DCT probe sheath ex
31、cept for the sensing portion with a glass, plastic, ortubing with a lower thermoconductivity can improve the agreement between LiG and DCT measurements.6. DCT Criteria6.1 The DCT criteria shown in Table 1 are for various temperature measurement applications used in Committee D02 testmethods. DCT cri
32、teria listed in a test method take precedence over those shown in Table 1.NOTE 1The DCTs electronics are typically limited to an environment of 0 C to 35 C. A DCTs temperature limits can be found in its manual orin the manufacturers specifications.D8164 18a36.2 Probe Immersion DepthThis criteria qua
33、ntifies the distance from the DCT probe tip that should be covered by the materialbeing measured in order to obtain an accurate temperature measurement. Immersing the probe in a material by less than itsminimum immersion depth can result in temperature measurements that differ from actual temperatur
34、e. The error is dependent onthe temperature difference between the material being measured and surrounding (ambient) temperature. Immersions greater thanthis immersion depth are acceptable.6.3 Measurement DriftThe drift in calibration should be checked periodically and at least once per year. This c
35、an beaccomplished using Practice D7962 or Test Methods E644. When a DCTs calibration drifts in one direction over severalcalibration checks against a reference temperature, such as the ice point, it may be an indication of deterioration of the DCT. Theprobe is to be recalibrated, when the check valu
36、e differs by more than the calibration drift listed in Table 1 from the last probecalibration. See Practice E563, Test Methods E644, or Guide E1750 for more information regarding checking calibrations.NOTE 2For reference temperatures, additional information on preparing and using an ice bath can be
37、found in Practice E563. Guide E1750 providesguidance 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 is defined as63.2 % of the time it takes a DCT to fully respond to a step change in tempe
38、rature. The test is done This parameter is typicallymeasured by the DCT supplier and noted in the DCT specifications. The determination of response time is to be measuredaccording to Section 9 of Test Methods E644, where the step change begins with the DCT probe at an initial temperature of 20 C6 5
39、C air before transferring to water at 77 C 6 5 C with it flowing at 0.9 ms 6 0.09 ms past the sensor.sensor, or anequivalent method.6.5 CalibrationThe calibration temperature data should be evenly distributed over a devices When a device is calibrated forthe full nominal temperature range (Table 1)
40、or over the range of use if narrower than the nominal temperature range. the“range-of-use” is greater than 90 C, the calibration data should consist of a minimum of four data points. When the“range-of-use“ is from 30 C to 90 C then a minimum of three data points are sufficient. When the “range-of-us
41、e” is less than30 C then a minimum of two data points are sufficient. The calibration data should be included in calibration report. Thecalibration report should be obtained from a calibration laboratory with demonstrated competency in temperature calibration whichis traceable to a national calibrat
42、ion laboratory or metrology standards body. An example is a calibration laboratory with a ISO17025 accreditation that includes temperature calibration.6.6 ThermowellsWhen inserting a DCT probe into a thermowell with a larger diameter, a sleeve is needed to ensure goodthermal transfer from the wall t
43、o the DCT sheath. This sleeve is to be made from a thermally conductive substance such as metalsuch as copper, brass, bronze, aluminum, steel, or other material.6.7 A DCT Certification/Calibration report may differ from a liquid-in-glass thermometer since a system adjustment can allowreadings to be
44、closely matched to the reference at the test point values. If system adjustments can not be made then the report needsto include the correction factors needed to bring the display temperature to the correct value along with guidance on applying them.Areport may showAS FOUND values that were document
45、ed before adjustments, andAS LEFT which are the values documentedafter adjustments may have been made. A DCTs accuracy (tolerance) as shown in its calibration report is to be consistent withthose listed for its “E2877 Class”.7. DCT Citation7.1 The DCT citation referencing these criteria in a standar
46、d should include the D02-DCT designation, any variance from thecriteria in Table 1, and include the information in subsections 6.2 through 6.5.8. Keywords8.1 DCT; digital contact thermometers; LiG; liquid-in-glass thermometersD8164 18a4TABLE 1 DCT Criteria for D02 Test MethodsNOTE 1When making measu
47、rements 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 E2251 listed LiGThermometers5C,
48、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 D445Potential application D97, D2500, D5853 D97, D5853 D97, D2500, D5853 D445Temperature sensor placementA
49、 Sample Sample Sample Temperature bathTemperature sensor placementA Sample Sample Sample Temperature BathParameter DCT CriteriaE2877 Class, minimum F F F ANominal temperature range,B C 38 to 50 32 to 127 80 to 20 80 to 20Display resolution, C minimum 0.1 0.1 0.1 0.01Accuracy,C C minimum 0.5 0.5 0.5 0.05Sensor type (Note 1 and Note 2) PRT, Thermistor PRT, Thermistor PRT, Thermistor PRTSensor sheath,D max diameter, mm 4.2E 4.2 4.2E 7Sensor length,F max mm 10 10 10 45Probe immersion depth by D7962,Gmm(see 6.2)40 40 40 105Measurement dr
