1、Designation: D3321 13Standard Test Method forUse of the Refractometer for Field Test Determination of theFreezing Point of Aqueous Engine Coolants1This standard is issued under the fixed designation D3321; the number immediately following the designation indicates the year oforiginal adoption or, in
2、 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.1. Scope*1.1 This test method covers the use of a portable refracto-meter for determining the a
3、pproximate freezing protectionprovided by ethylene and propylene glycol-based coolantsolutions as used in engine cooling systems and specialapplications.NOTE 1Some instruments have a supplementary freezing protectionscale for methoxypropanol coolants. Others carry a supplemental scalecalibrated in d
4、ensity or specific gravity readings of sulfuric acid solutionsso that the refractometer can be used to determine the charged conditionof lead acid storage batteries.1.2 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.3 This s
5、tandard 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 and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.
6、1 ASTM Standards:2D1177 Test Method for Freezing Point of Aqueous EngineCoolantsE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3. Summary of Test Method3.1 These coolant testers
7、are critical-angle refractometersdesigned for rapid, approximate measurement of ethylene andpropylene glycol coolant freezing point protection. Only a fewdrops of test solution are required. Some testers automaticallycorrect for ambient air temperature and the temperature of thesolution being tested
8、. The instrument is rugged, simple to read,and easy to clean and maintain.3.2 The coolant freezing point readings are taken at pointswhere the dividing line between light and dark crosses thescales. Some refractometers have a coolant scale for indicatingthe freezing point of aqueous ethylene glycol
9、coolants only,while other refractometers also have a scale for indicating thefreezing point of aqueous propylene glycol coolants. The rangeof the scales varies from one device to another.3.3 Freezing point measurements are concentration-relatedvalues and are in turn directly related to refractive in
10、dex. It hasbeen empirically determined that freezing point measurementsare accurate within 1C (2F).4. Significance and Use4.1 This practice is commonly used by vehicle servicepersonnel to determine the freezing point, in degrees Celsius orFahrenheit, of aqueous solutions of commercial ethylene andpr
11、opylene glycol-based coolant. A durable hand-held refracto-meter is available that reads the freezing point, directly, indegrees Celsius or Fahrenheit, when a few drops of enginecoolant are properly placed on the temperature-compensatedprism surface of the refractometer. This refractometer is forgly
12、col and water solutions, and is not suitable for other coolantsolutions.4.2 The hand-held refractometer should be calibrated beforeuse (see Section 7).4.3 Care must be taken to use the correct glycol freezingpoint scale for the glycol type being measured. Use of thewrong glycol scale can result in f
13、reezing point errors of 18 andmore degrees Fahrenheit.1This test method is under the jurisdiction of ASTM Committee D15 on EngineCoolants and Related Fluids and is the direct responsibility of SubcommitteeD15.03 on Physical Properties.Current edition approved May 1, 2013. Published June 2013. Origin
14、allyapproved in 1974. Last previous edition approved in 2012 as D3321 12. DOI:10.1520/D3321-13.2For 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 Documen
15、t Summary page onthe ASTM website.*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 States14.4 Ethylene glycol/propylene glycol mixtures will result ininaccurate freezing point m
16、easurements using either freezingpoint scale.5. Interferences5.1 Interference can occur if the mixture is contaminated orif the prism surface is not clean. The presence of other glycolssuch as diethylene glycol in small amounts will not causeinterference.6. Apparatus6.1 The hand-held critical angle
17、refractometer is a ruggeddie-cast portable instrument that is covered with a high-impactplastic to minimize damage to the eyepiece lens if dropped. Apolished glass prism is opposite the viewing end. A hingedplastic cover is moved over the prism (sampling end) to allowfor even sample distribution and
18、 prevent liquid sample spillageduring the test. No eyepiece or prism adjustments are requiredfor sample testing.6.2 The telescopic recessed eyepiece is located at one endand the graduated, translucent prism on the opposite end (seeFig. 1).7. Calibration7.1 Calibration of these coolant testers should
19、 periodicallybe verified by testing a water sample in accordance with theprocedure outlined in Section 8.7.2 If the sample tested deviates from 0C (+32F) thecoolant tester is out of calibration and should be recalibrated.7.3 This calibration test is best performed with the coolanttester and water sa
20、mple at room temperature. If the instrumentused is designed to be automatically temperature compensated,work within the stated temperature-compensated range.8. Procedure8.1 CleaningBefore using, swing back the plastic cover atthe slanted end of the tester exposing both the measuringwindow and the bo
21、ttom of the plastic cover. Wipe both cleanand dry with tissue or clean soft cloth. Close the plastic cover(see Fig. 2).8.2 Testing Coolant SolutionCommercial instruments areusually equipped with a small suction pipet for samplingsolutions. This tube should be used to remove a sample (frombelow the c
22、oolant surface) and eject a few drops on themeasuring window (see Fig. 3). Flush suction pipet with testsolution before withdrawing sample for testing.8.3 Readings:8.3.1 Point the instrument toward any light source (forexample, a headlight) and look into the eyepiece (Fig. 4).8.3.2 The freeze point
23、protection is the point where thedividing line between light and dark (edge of the shadow)crosses the scale; read the scale marked for the type of coolantbeing tested (see Fig. 5).NOTE 2Tester temperature scales are reversed from standard ther-mometer scales. Below zero readings are located on upper
24、 half of scale.8.3.3 A little experience is required to obtain the bestcontrast between the light and dark portions of the scale. Tiltthe instrument towards the light source until best results areobtained.NOTE 3Refractometer freezing point scales are available in C and Ffor both propylene glycol and
25、 ethylene glycol-base coolants.8.3.4 If the edge of the shadow is not sharp, the measuringsurfaces were not sufficiently well cleaned or dried or aninsufficient amount of coolant sample was used. Clean and drythe window. Conduct a new test.FIG. 1 Hand-Held Critical Angle RefractometerFIG. 2 Cleaning
26、D3321 132NOTE 4Oil contamination will reduce the sharpness of the dividingline.8.3.5 A completely dark scale indicates insufficient coolantsample was used. Completely light scale indicates that thecoolant freezing point is below the scale range.8.3.6 There is a danger of the loss of water vapor from
27、 themixture, due to the small amount of sample required, if thesolution is sampled at elevated temperatures. Under thesecircumstances the reading should be taken immediately. Moreaccurate readings are obtained when testing at ambient tem-perature.9. Precision and Bias9.1 The precision of this test m
28、ethod is based on aninterlaboratory study conducted in 2011. Twelve laboratoriestested four different materials for two different properties. Each“test result” represents an individual determination. Eachlaboratory reported triplicate test results for each analysis.Practice E691 was followed for the
29、 design and analysis of thedata; the details are given in RR:D15-1032.39.1.1 Repeatability Limit, rTwo test results obtainedwithin one laboratory shall be judged not equivalent if theydiffer by more than the r value for that material; r is the intervalrepresenting the critical difference between two
30、 test results forthe same material, obtained by the same operator using thesame equipment on the same day in the same laboratory.9.1.1.1 Repeatability limits are listed in Tables 1 and 2.9.1.2 Reproducibility Limit, RTwo test results shall bejudged not equivalent if they differ by more than the R va
31、luefor that material; R is the interval representing the criticaldifference between two test results for the same material,obtained by different operators using different equipment indifferent laboratories.9.1.2.1 Reproducibility limits are listed in Tables 1 and 2.9.1.3 The above terms (repeatabili
32、ty limit and reproducibil-ity limit) are used as specified in Practice E177.9.1.4 Any judgment in accordance with statements 9.1.1and 9.1.2 would have an approximate 95% probability of beingcorrect.9.2 BiasAt the time of the study, there was no acceptedreference material suitable for determining the
33、 bias for this testmethod, therefore no statement on bias is being made.9.3 The precision statement was determined through statis-tical examination of 288 results, from twelve laboratories, onfour different materials.10. Keywords10.1 engine coolants; freezing point; refractometer3Supporting data are
34、 available from ASTM Headquarters. Request RR:D15-1032.NOTE 1Do not remove clear plastic pump from tester. Release tip ofpump from tester housing and insert into radiator filler neck or coolantreservoir tank. Be sure to insert well below level of fluid. Press and releasebulb to draw up a sample of c
35、oolant. Eject the liquid to flush the tube.Repeat filling to obtain sample. Bend plastic tube around tester so that tipcan be inserted in cover plate opening. Eject a few drops of coolant ontomeasuring surface by pressing bulb. Ensure that the sample is notcontaminated with oil.FIG. 3 SamplingFIG. 4
36、 ReadingFIG. 5 Tester Temperature ScaleD3321 133SUMMARY OF CHANGESCommittee D15.03 has identified the location of selected changes to this standard since the last issue(D332112) that may impact the use of this standard.(1) Remove note 3 sole source reference. (2) Change note 4 to note 3.ASTM Interna
37、tional takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely th
38、eir own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should
39、 be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standa
40、rds, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-83
41、2-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).TABLE 1 Ethylene Glycol (EG), %Material Average, ARepeatabilityStandard Deviatio
42、n, SrReproducibilityStandard Deviation, SRRepeatabilityLimit, rReproducibilityLimit, RSample No. 1:Ethylene Glycolin Water50.50 0.00 1.00 0.00 2.80Sample No. 2:Conventional FullyFormulated EG49.53 0.17 0.63 0.47 1.75Sample No. 3:ELC #150.44 0.17 0.87 0.47 2.43Sample No. 4:ELC #251.58 0.29 0.83 0.81
43、2.32AThe average of the laboratories calculated averages.TABLE 2 Freeze Point, CMaterial Average, ARepeatabilityStandard Deviation, SrReproducibilityStandard Deviation, SRRepeatabilityLimit, rReproducibilityLimit, RSample No. 1:Ethylene Glycolin Water-35.67 0.33 2.09 0.93 5.84Sample No. 2:Conventional FullyFormulated EG-32.92 0.47 1.86 1.32 5.21Sample No. 3:ELC #1-35.03 0.37 1.85 1.04 5.17Sample No. 4:ELC #2-38.44 0.29 2.05 0.81 5.74AThe average of the laboratories calculated averages.D3321 134
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