1、Designation:D332113Standard 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 the
2、 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 approximate
3、 freezing protectionprovided by ethylene and propylene glycol-based coolantsolutions as used in engine cooling systems and specialapplications.NOTE1Some instruments have a supplementary freezing protectionscale for methoxypropanol coolants.Others carry a supplemental scalecalibrated in density or sp
4、ecific 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 standard does
5、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 Documents2.1 ASTM Standards:
6、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 are critical-angle
7、 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.The instrument is ru
8、gged,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 coolants only,while othe
9、r 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 index.It hasbeen empiricall
10、y 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 andpropylene glycol-based coolant.A
11、 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 forglycol and water solutions,and is not
12、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 freezing point errors of 18 andmore deg
13、rees 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.Originallyapproved in 1974.Last previous editio
14、n 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 Document Summary page onthe ASTM website.*A Summary of
15、Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 4.4 Ethylene glycol/propylene glycol mixtures will result ininaccurate freezing point measurements using either freezingpoint scale.5.Inter
16、ferences5.1 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 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
