1、Designation: D 6660 01 (Reapproved 2007)Standard Test Method forFreezing Point of Aqueous Ethylene Glycol Base EngineCoolants by Automatic Phase Transition Method1This standard is issued under the fixed designation D 6660; the number immediately following the designation indicates the year oforigina
2、l adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of the freez-ing point
3、of an aqueous engine coolant solution.1.2 This test method is designed to cover ethylene glycolbase coolants up to a maximum concentration of 60 % (v/v) inwater; however, the ASTM interlaboratory study mentioned in12.2 has only demonstrated the test method with sampleshaving a concentration range of
4、 40 to 60 % (v/v) water.NOTE 1Where solutions of specific concentrations are to be tested,they shall be prepared from representative samples as directed in TestMethod D 1176. Secondary phases separating on dilution need not beseparated.NOTE 2The products may also be marketed in a ready-to-use form(p
5、rediluted).1.3 The values stated in SI units are to be regarded as thestandard. The values given in parenthesis are for informationonly.1.4 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 es
6、tablish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 1176 Practice for Sampling and Preparing Aqueous So-lutions of Engine Coolants or Antirusts for Testing Pur-posesD 1177 Test Method fo
7、r Freezing Point of Aqueous EngineCoolantsD 3306 Specification for Glycol Base Engine Coolant forAutomobile and Light-Duty ServiceD 6210 Specification for Fully-Formulated Glycol BaseEngine Coolant for Heavy-Duty Engines3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 automatic
8、 phase transition method, nin this stan-dard, the procedures of automatically cooling an enginecoolant sample until solid crystals appear, followed by con-trolled warming and recording the temperature at which thecrystals redissolve into the liquid phase.3.1.2 freezing point, nthe temperature at whi
9、ch crystalli-zation begins in the absence of supercooling, or the maximumtemperature reached immediately after initial crystal formationin the case of supercooling, or the temperature at which solidcrystals, formed on cooling, disappear when the temperature ofthe specimen is allowed to rise.3.1.3 pe
10、ltier device, na solid state thermoelectric deviceconstructed with dissimilar semiconductor materials, config-ured in such a way that it will transfer heat to and away froma test specimen dependent on the direction of electric currentapplied to the device.4. Summary of Test Method4.1 A specimen is c
11、ooled by a Peltier device while continu-ously being illuminated by a light source. The specimen iscontinuously monitored by an array of optical detectors for thefirst formation of crystals. Once the crystals are formed, thespecimen is then warmed at controlled rates until all thecrystals return to t
12、he liquid phase. The detectors are sufficientin number to ensure that any crystals are detected. Thespecimen temperature at which the crystals return to the liquidphase is recorded by the temperature sensor as the freezingpoint.5. Significance and Use5.1 The freezing point of an engine coolant indic
13、ates thecoolant freeze protection.5.2 The freezing point of an engine coolant may be used todetermine the approximate glycol content, provided the glycoltype is known.5.3 Freezing point as measured by Test Method D 1177 orapproved alternative method is a requirement in SpecificationsD 3306 and D 621
14、0.1This test method is under the jurisdiction of ASTM Committee D15 on EngineCoolants and is the direct responsibility of Subcommittee D15.03 on PhysicalProperties.Current edition approved April 1, 2007. Published May 2007. Originallyapproved in 2001. Last previous edition approved in 2001 as D 6660
15、 - 01e1.2For 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.1Copyright ASTM International, 100 Barr Harbor Drive,
16、 PO Box C700, West Conshohocken, PA 19428-2959, United States.5.4 This test method provides results that are equivalent toTest Method D 1177 and expresses results to the nearest 0.1Cwith improved reproducibility over Test Method D 1177.5.5 This test method determines the freezing point in ashorter p
17、eriod of time than Test Method D 1177.5.6 This test method removes most of the operator time andjudgement required by Test Method D 1177.6. Apparatus6.1 Automatic Apparatus3The apparatus described in thismethod consists of a test chamber controlled by a micropro-cessor that is capable of cooling and
18、 heating the test specimen,optically observing the appearance and disappearance of solidcrystals and recording the temperature of the specimen.6.2 The apparatus shall be equipped with a specimen cup,optical detector array, light source, digital display, Peltierdevice and a specimen temperature measu
19、ring device.6.3 The temperature measuring device in the specimen cupshall be capable of measuring the temperature of the testspecimen from -80C to +50C at a resolution of 0.1C.6.4 The apparatus shall be equipped with fittings to permitthe circulation of liquid cooling media to remove heat gener-ated
20、 by the Peltier device and other electronic components ofthe apparatus.7. Reagents and Materials7.1 Cooling MediaLiquid heat exchange media to removethe heat generated by the Peltier device and other electroniccomponents from the apparatus.NOTE 3Some apparatus are designed to use tap water as coolin
21、gmedia to bring specimen temperature to -60C. To achieve cooling ofspecimen to -80C, provide circulation of liquid cooling media at -30C orlower to the apparatus. Refer to manufacturers operating instructions onthe relationship between cooling media temperature and the minimumspecimen temperature.7.
22、2 Adjustable Volume Pipette4, capable of dispensing 0.156 0.01 ml of sample.7.3 Cotton Swabs5Plastic or paper shaft cotton swabs toclean the specimen cup.NOTE 4Caution: The use of swabs with wooden shafts may damagethe mirrored surface of the specimen cup.8. Preparation of Apparatus8.1 Install the a
23、nalyzer for operation in accordance withmanufacturers instructions.8.2 Make liquid cooling media connections and ensure thatthey do not leak.8.3 Turn on the liquid cooling media.8.4 Turn on the main power switch of the analyzer.After theautomatic self diagnostics start-up sequence is completed, thei
24、nstrument will display a “READY” message.9. Calibration and Standardization9.1 Ensure that all of the manufacturers instructions forcalibrating, checking and operating the apparatus are followed.9.2 A sample with a mutually agreed upon freezing pointcan be used to verify performance of the apparatus
25、.10. Procedure10.1 Open the test chamber lid and clean the specimen cupinside the test chamber with a cotton swab.10.2 Use the pipette to deliver 0.15 ml 6 0.01 ml ofspecimen into the specimen cup. Clean the specimen out of thecup by using a cotton swab. The cup should be cleaned to thepoint where n
26、o visible droplets of specimen remain in the cup.10.3 Repeat step 10.2.10.4 Carefully measure 0.15 ml 6 0.01 ml of specimen intothe specimen cup.10.5 Close and lock the test chamber lid.10.6 Push the “RUN” button located on the front panel ofthe apparatus. The specimen is cooled by the Peltier devic
27、ewhile the appearance of solid crystals is continuously moni-tored by the optical detectors. The temperature of the specimenis continuously monitored and displayed on the front panel ofthe apparatus. Once the crystals are detected, the specimen isthen warmed until all the crystals re-dissolve into t
28、he liquidphase. The measurement is automatically terminated once thefreezing point is detected.10.7 When the measurement is complete the freezing pointvalue per D 6660 will be displayed on the front panel of theapparatus.10.8 Unlock and open the test chamber lid and clean thespecimen out of the spec
29、imen cup with a cotton swab.11. Report11.1 Report the temperature recorded in 10.7 as the freezingpoint, Test Method D 6660.12. Precision and Bias12.1 PrecisionThe precision of this test method as deter-mined by the statistical examination of the interlaboratory6testresults is as follows:12.1.1 Repe
30、atabilityThe difference between two test re-sults obtained by the same operator with the same apparatusunder constant operating conditions on identical test materialwould, in the long run, in the normal and correct operation ofthe test method, exceed 0.6C (1.1F) only in one case intwenty.12.1.2 Repr
31、oducibilityThe difference between two singleand independent results obtained by different operators work-ing in different laboratories on identical test material would, inthe long run, in the normal and correct operation of the testmethod, exceed 0.8C (1.4F) only in one case in twenty.3The following
32、 instrument has been found suitable for use in this test method:Phase Technology Freezing Point Analyzer model series 70 and 70V. The solesource of supply of the apparatus known to the committee at this time is PhaseTechnology, i 1168 Hammersmith Gate, Richmond, B.C. Canada, V7A 5H8. If youare aware
33、 of alternative suppliers, please provide this information to ASTMInternational Headquarters. Your comments will receive careful consideration at ameeting of the responsible technical committee,1which you may attend.4A suitable pipette is an Eppendorf pipette.5Suitable cotton swabs are Q-tips or equ
34、ivalent with paper or plastic shafts.6The results of the 1999 Interlaboratory Cooperative Test Program are availablefrom ASTM Headquarters. Request ASTM RR:D15-1020.D 6660 01 (2007)212.2 Relative BiasThe automatic method displayed amean bias of 0.67 C relative to the manual procedure, TestMethod D 1
35、177. It is not statistically significant at the 95 %confidence level.The precision statements were derived from a 1999 inter-laboratory cooperative test program. Participants analyzed 5sample sets comprised of ethylene glycol base coolant theconcentration range of 40 to 60 volume in 5 % volumeincrem
36、ents. Eight laboratories participated with the automaticphase transition apparatus and seven participated with themanual D 1177 test method. The interlaboratory program wasconducted double blind. Two analysts measured different setsof samples by each method at seven of the laboratories. Onelaborator
37、y performed only the automatic method. Each labo-ratory received two sets of randomized samples labelled Athough E and 1 to 5.Atotal of twenty five repeat measurementswere distributed over the laboratories. The precision statisticswere compiled and calculated based on the 0.1C resolutionoffered by t
38、he automatic phase transition method. Informationon the types of samples and their respective average freezingpoint is contained in the research report.13. Keywords13.1 aqueous engine coolants; crystals; engine coolants;freezing point; Peltier; thermoelectricANNEX(Mandatory Information)A1. APPARATUS
39、A1.1 Test Chamber, comprised of optical detectors, lens,light source, specimen cup, temperature sensor, Peltier deviceand heat sink arranged in a configuration as shown in Fig.A1.1. The lid of the test chamber can be opened to allowcleaning of specimen cup and introduction of new specimen.Once close
40、d and locked, the chamber becomes airtight. AnO-ring is used to seal the mating surfaces between the lid andthe rest of the chamber. The test chamber wall is made ofblack-colored metal and plastic components to minimize lightreflection.A1.1.1 Specimen Cup, comprised of black plastic wall and ahighly
41、 polished metal bottom. The polished surface of thebottom serves as a reflective surface for light. The transfer ofheat to and away from the specimen, through the metal bottom,is controlled by the Peltier device.A1.1.2 Temperature Sensor, reading to 0.1C, permanentlyembedded into the bottom of the s
42、pecimen cup and positionedless than 0.1 mm below the top surface of the cup bottom. Thistemperature sensor, which is made of a single strand platinum,provides accurate measurement of the specimen temperature.A1.1.3 Peltier Device, capable of controlling the specimentemperature over a wide range. The
43、 range varies depending onthe model series. During specimen cooling, heat is transferredfrom the top of the device to the bottom. Since the top is inthermal contact with the bottom of the specimen cup thespecimen will be chilled. The bottom of the Peltier device is inFIG. A1.1 Schematic of Test Cham
44、berD 6660 01 (2007)3thermal contact with the heat sink, where heat is dissipated tothe cooling media. During specimen warming, the reverseprocess will take place.A1.1.4 Light Source, to provide a beam of light with awavelength of 660 6 10 nm. The light source is positionedsuch that it provides an in
45、cident beam (Fig. A1.1) impingingonto the specimen at a specified angle. The light is reflectedfrom the polished bottom of the specimen cup. When thespecimen is a homogeneous liquid, the reflected beam im-pinges onto the chamber lid, which is black in color. Thereflected light is then absorbed by th
46、e black surface. Whensolid crystals appear in the specimen, the reflected beam isscattered by the solid liquid phase boundaries. A significantamount of scattered light impinges onto the lens (Fig. A1.2)A1.1.5 Optical Detectors positioned above the lens tomonitor the clarity of the specimen. The dist
47、ance between theoptical detectors and the lens is adjusted such that the image ofthe specimen is projected onto the light sensitive surface of theoptical detectors. Sufficient optical detectors are used to coverthe image area.A1.2 Apparatus Exterior Interface is composed of severaldisplays and butto
48、ns as shown in Fig. A1.3 (the exact layout ofthe displays and buttons may vary slightly depending on themodel series).A1.2.1 Message Display provides information on the statusof the apparatus. It displays a READY message when theapparatus is idle and no fault is found. At the end of a test, theresul
49、t is displayed. It displays a diagnostic message if a fault isdetected in any of the major components of the apparatus.Detailed explanation of the diagnostic messages are availablein the manufacturers users manual.A1.2.2 Specimen Temperature Display gives an update ofthe specimen temperature, recorded to 0.1 C, every 2 s.A1.2.3 Light Signal Display gives an update of the scat-tered light level received by the optical detectors every 2 s.This information is used by service personnel for troubleshoot-ing purposes.A1.2.4 RUN Button allows the operator t
