1、Designation: D6660 01 (Reapproved 2014)1Standard Test Method forFreezing Point of Aqueous Ethylene Glycol Base EngineCoolants by Automatic Phase Transition Method1This standard is issued under the fixed designation D6660; the number immediately following the designation indicates the year oforiginal
2、 adoption or, in the case of 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.1NOTEUnits information was corrected and Note 4 was changed to a warning statem
3、ent and included in Section 7.3editorially in July 2014.1. Scope1.1 This test method covers the determination of the freez-ing point 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; howev
4、er, the ASTM interlaboratory study mentioned in12.2 has only demonstrated the test method with sampleshaving a concentration range of 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
5、D1176. Secondary phases separating on dilution need not beseparated.NOTE 2The products may also be marketed in a ready-to-use form(prediluted).1.3 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.4 This standard does not purpor
6、t 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 and health practices and determine the applica-bility of regulatory limitations prior to use. Some specifichazards statements are given in 7.
7、3.2. Referenced Documents2.1 ASTM Standards:2D1176 Practice for Sampling and Preparing Aqueous Solu-tions of Engine Coolants or Antirusts for Testing PurposesD1177 Test Method for Freezing Point of Aqueous EngineCoolantsD3306 Specification for Glycol Base Engine Coolant forAutomobile and Light-Duty
8、ServiceD6210 Specification for Fully-Formulated Glycol Base En-gine Coolant for Heavy-Duty Engines3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 automatic phase transition method, nin thisstandard, the procedures of automatically cooling an enginecoolant sample until solid cr
9、ystals 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 which crystalli-zation begins in the absence of supercooling, or the maximumtemperature reached immediately after initial cryst
10、al 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 peltier device, na solid state thermoelectric deviceconstructed with dissimilar semiconductor materials, config-ured in such a
11、 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 cooled by a Peltier device while continu-ously being illuminated by a light source. The specimen iscontinuously monitored by
12、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 the liquid phase. The detectors are sufficientin number to ensure that any crystals are detected. Thespecimen temperature at
13、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 indicates thecoolant freeze protection.1This test method is under the jurisdiction of ASTM Committee D15 on EngineCoolants and Re
14、lated Fluids and is the direct responsibility of SubcommitteeD15.03 on Physical Properties.Current edition approved July 1, 2014. Published July 2014. Originally approvedin 2001. Last previous edition approved in 2007 as D6660 - 01(2007). DOI:10.1520/D6660-01R14E01.2For referenced ASTM standards, vi
15、sit 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 19428-2
16、959. United States15.2 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 D1177 orapproved alternative method is a requirement in SpecificationsD3306 and D6210.5.4 This test me
17、thod provides results that are equivalent toTest Method D1177 and expresses results to the nearest 0.1Cwith improved reproducibility over Test Method D1177.5.5 This test method determines the freezing point in ashorter period of time than Test Method D1177.5.6 This test method removes most of the op
18、erator time andjudgement required by Test Method D1177.6. Apparatus6.1 Automatic Apparatus3The apparatus described in thismethod consists of a test chamber controlled by a micropro-cessor that is capable of cooling and heating the test specimen,optically observing the appearance and disappearance of
19、 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 measuring device.6.3 The temperature measuring device in the specimen cupshall be capab
20、le 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 by the Peltier device and other electronic components ofthe apparatus.7. Reagents
21、 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 coolingmedia to bring specimen temperature to -60C. To achieve cooling ofspecimen to -80
22、C, 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.7.2 Adjustable Volume Pipette,4capable of dispensing 0.156 0.01 ml of sample.7.3 Cot
23、ton Swabs5Plastic or paper shaft cotton swabs toclean the specimen cup. (WarningThe use of swabs withwooden shafts may damage the mirrored surface of thespecimen cup.)8. Preparation of Apparatus8.1 Install the analyzer for operation in accordance withmanufacturers instructions.8.2 Make liquid coolin
24、g 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, theinstrument will display a “READY” message.9. Calibration and Standardization9.1 Ensure tha
25、t 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.10. Procedure10.1 Open the test chamber lid and clean the specimen cupinside the test ch
26、amber 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 no visible droplets of specimen remain in the cup.10.3 Repeat step 10.2.10.4 Carefully mea
27、sure 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 devicewhile the appearance of solid crystals is continuously moni-tored by the optical detecto
28、rs. 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 the liquidphase. The measurement is automatically terminated once thefreezing point is det
29、ected.10.7 When the measurement is complete the freezing pointvalue per Test Method D6660 will be displayed on the frontpanel of the apparatus.10.8 Unlock and open the test chamber lid and clean thespecimen out of the specimen cup with a cotton swab.11. Report11.1 Report the temperature recorded in
30、10.7 as the freezingpoint, Test Method D6660.12. Precision and Bias12.1 PrecisionThe precision of this test method as deter-mined by the statistical examination of the interlaboratory6testresults is as follows:3The following instrument has been found suitable for use in this test method:Phase Techno
31、logy 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 of alternative suppliers, please provide this information to ASTMInternatio
32、nal 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 equivalent with paper or plastic shafts.6The results of the 1999 Interlaborator
33、y Cooperative Test Program are availablefrom ASTM Headquarters. Request ASTM RR:D15-1020.D6660 01 (2014)1212.1.1 RepeatabilityThe 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
34、 run, in the normal and correct operation ofthe test method, exceed 0.6C only in one case in twenty.12.1.2 ReproducibilityThe difference between two singleand independent results obtained by different operators work-ing in different laboratories on identical test material would, inthe long run, in t
35、he normal and correct operation of the testmethod, exceed 0.8C only in one case in twenty.12.2 Relative BiasThe automatic method displayed amean bias of 0.67C relative to the manual procedure, TestMethod D1177. It is not statistically significant at the 95 %confidence level.12.3 The precision statem
36、ents were derived from a 1999interlaboratory cooperative test program. Participants analyzedfive sample sets comprised of ethylene glycol base coolant theconcentration range of 40 to 60 volume in 5 % volumeincrements. Eight laboratories participated with the automaticphase transition apparatus and s
37、even participated with themanual D1177 test method. The interlaboratory program wasconducted double blind. Two analysts measured different setsof samples by each method at seven of the laboratories. Onelaboratory performed only the automatic method. Each labo-ratory received two sets of randomized s
38、amples labelled Athough E and 1 to 5. A total of 25 repeat measurements weredistributed over the laboratories. The precision statistics werecompiled and calculated based on the 0.1C resolution offeredby the automatic phase transition method. Information on thetypes of samples and their respective av
39、erage freezing point iscontained in the research report.13. Keywords13.1 aqueous engine coolants; crystals; engine coolants;freezing point; Peltier; thermoelectricANNEX(Mandatory Information)A1. APPARATUSA1.1 Test Chamber, comprised of optical detectors, lens,light source, specimen cup, temperature
40、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 closed and locked, the chamber becomes airtight. AnO-ring is used to seal the mating surfaces between
41、 the lid andthe rest of the chamber. The test chamber wall is made ofblack-colored metal and plastic components to minimize lightreflection.FIG. A1.1 Schematic of Test ChamberD6660 01 (2014)13A1.1.1 Specimen Cup, comprised of black plastic wall and ahighly polished metal bottom. The polished surface
42、 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 specimen cup and positionedless than 0.1 mm b
43、elow 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 range varies depending onthe model series.
44、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 inthermal contact with the heat sink, where heat is dissipated tothe cooling m
45、edia. 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 incident beam (Fig. A1.1) impingingonto the specimen at a specified angle. The light is reflectedf
46、rom 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 the black surface. Whensolid crystals appear in the specimen, the reflected beam isscattered by th
47、e 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 distance between theoptical detectors and the lens is adjusted such that the image ofthe specimen is
48、 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 buttons as shown in Fig. A1.3 (the exact layout ofthe displays and buttons may vary slightly dependin
49、g 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, theresult 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 0.1C, every 2 s.A1.2.3 Light Signal Displa
