1、Designation: D 3321 94 (Reapproved 2002)Standard Test Method forUse of the Refractometer for Field Test Determination of theFreezing Point of Aqueous Engine Coolants1This standard is issued under the fixed designation D 3321; the number immediately following the designation indicates the year oforig
2、inal 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 use of a portable refracto-meter f
3、or determining the approximate 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
4、scalecalibrated in density 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 inform
5、ationonly.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 and health practices and determine the applica-bility of regulatory limitations prior to use.2. Re
6、ferenced Documents2.1 ASTM Standards:D 1177 Test Method for Freezing Point of Aqueous EngineCoolants23. Summary of Test Method3.1 These coolant testers3are critical-angle refractometersdesigned for rapid, approximate measurement of ethylene andpropylene glycol coolant freezing point protection. Only
7、 a fewdrops of test solution are required. Some testers automaticallycorrect for ambient air temperature and the temperature of thesolution being tested. 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 divid
8、ing line between light and dark crosses thescales. Some refractometers have a coolant scale for indicatingthe freezing point of aqueous ethylene glycol coolants only,while other refractometers also have a scale for indicating thefreezing point of aqueous propylene glycol coolants. The rangeof the sc
9、ales varies from one device to another.3.3 Freezing point measurements are concentration-relatedvalues and are in turn directly related to refractive index. It hasbeen empirically determined that freezing point measurementsare accurate within 1C (2F).4. Significance and Use4.1 This practice is commo
10、nly used by vehicle servicepersonnel to determine the freezing point, in degrees Celsius orFahrenheit, of aqueous solutions of commercial ethylene andpropylene glycol-based coolant. A durable hand-held refracto-meter is available that reads the freezing point, directly, indegrees Celsius or Fahrenhe
11、it, when a few drops of enginecoolant are properly placed on the temperature-compensatedprism surface of the refractometer. This refractometer is forglycol and water solutions, and is not suitable for other coolantsolutions.4.2 The hand-held refractometer should be calibrated beforeuse (see Section
12、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 freezing point errors of 18 andmore degrees Fahrenheit.4.4 Ethylene glycol/propylene glycol mixtures will result ininaccurate freezing point measurem
13、ents 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 refract
14、ometer 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 allow1This test method is under the jurisdic
15、tion of ASTM Committee D15 on EngineCoolants and is the direct responsibility of Subcommittee D15.03 on PhysicalProperties.Current edition approved Aug. 15, 1994. Published October 1994. Originallypublished as D 3321 74. Last previous edition D 3321 93.2Annual Book of ASTM Standards, Vol 15.05.3Cool
16、ant testers are available from Leica Inc., P.O. Box 123, Buffalo, NY 14240and Misco Products, 3401 Virginia Rd., Cleveland, OH 44122.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.for even sample distribution and prevent liquid samp
17、le 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 periodicallybe veri
18、fied 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 sample at room tempera
19、ture. 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 bottom of the plastic
20、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 coolant surface) and
21、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 protection is the po
22、int 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 half of scale.8.3.3
23、 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 ethylene glycol-bas
24、e 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.NOTE 4Oil contamination will reduce the sharpness of the dividingline.8.3.5 A co
25、mpletely 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 themixture, due to the small amount of sample required, if thesolution is sampled at ele
26、vated temperatures. Under thesecircumstances the reading should be taken immediately. Moreaccurate readings are obtained when testing at ambient tem-perature.9. Precision and Bias49.1 PrecisionThe precision of this test method, as deter-mined by the examination of the interlaboratory test results, i
27、sas follows:4Supporting data are available from ASTM Headquarters. Request RR:D15-1012.FIG. 1 Hand-Held Critical Angle RefractometerFIG. 2 CleaningD 3321 94 (2002)29.1.1 For different test operators using the specified equip-ment and the procedure in Section 8, the results should not varymore than 0
28、.5C (1.0F) when the temperature of the coolantsolution is 24C (75F) or more than 1C (2F) from theaverage value when the coolant solution temperature is 82C(180F).9.1.2 Table 1 lists the freezing points obtained by TestMethod D 1177 and the refractometer for representative glycolantifreeze/coolant mi
29、xtures and water.9.2 BiasSince there is no acceptable reference materialsuitable for determining the bias for this test method, bias hasnot been determined.10. Keywords10.1 engine coolants; freezing point; refractometerASTM International takes no position respecting the validity of any patent rights
30、 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 their own responsibility.This standard is subject to revision at any ti
31、me 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 be addressed to ASTM International Headquarters. Your comments will
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33、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 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or t
34、hrough the ASTM website(www.astm.org).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 coolant. Eject the
35、 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 ReadingFIG. 5 Te
36、ster Temperature ScaleTABLE 1 Comparison of Freezing Points by Refractometerversus Test Method D 1177Base Glycol MixtureFreezing Point 50/50 Aqueous SolutionRefractometer, C (F)Test Method D 1177,C (F)95 % Ethylene glycol 33; 34 (28; 29) 34 (30)5%H2O90 % Ethylene glycol 34; 35 (30; 31) 34; 35 (30;31)5 % Propylene glycol5%H2O90 % Ethylene glycol 34; 34 (30; 30) 35 (31)5 % Diethylene glycol5%H2O90 % Ethylene glycol 34; 34 (29; 29) 34 (30)2.5 % Propylene glycol2.5 % Diethylene glycol5%H2OD 3321 94 (2002)3
