1、Designation:D 878 01e1Standard Test Method forInorganic Chlorides and Sulfates in Insulating Oils1This standard is issued under the fixed designation D 878;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A n
2、umber in parentheses indicates the year of last reapproval.Asuperscript epsilon(e)indicates an editorial change since the last revision or reapproval.This standard has been adopted for use by government agencies to replace Method 5703 of Federal Test Method Standard No.791b.e1NOTEEditorial changes w
3、ere made in January 2002.1.Scope1.1 This test method describes the qualitative determinationof inorganic chlorides and sulfates in electrical insulating oils.NOTE1It should be pointed out that if the strong acids,hydrochloricand sulfuric,are present,they will give positive results for chlorides ands
4、ulfates,respectively.1.2 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 u
5、se.2.Referenced Documents2.1 ASTM Standards:D 1193 Specification for Reagent Water23.Summary of Test Method3.1 Water is used to extract inorganic chlorides and sulfatesfrom a test specimen of insulating oil.A portion of the waterlayer is treated with nitric acid and silver nitrate to reveal awhite p
6、recipitate if chloride is present.A second portion istreated with hydrochloric acid and barium chloride.A whiteprecipitate indicates the presence of sulfate.4.Significance and Use4.1 The presence of inorganic chlorides and sulfates in oil incontact with metal surfaces in electrical equipment can res
7、ult incorrosion of transformer components.The deterioration ofmetal surfaces is dependent upon the quantity of the corrosiveagent and the operating environment.Although not quantita-tive,this test method is a means for recognizing the potentialfor such a hazard.5.Apparatus5.1Separatory Funnel,250-mL
8、 and 500-mL capacity.5.2Beakers,250-mL capacity.5.3Test Tubes,25-mL capacity.6.Reagents6.1 Purity of ReagentsUse reagent grade chemicals in alltests.Unless otherwise indicated,it is intended that all reagentsshall conform to the specifications of the Committee onAnalytical Reagents of the American C
9、hemical Society,wheresuch specifications are available.3Other grades may be used,provided it is first ascertained that the reagent is of sufficientlyhigh purity to permit its use without lessening the accuracy ofthe determination.6.2 Purity of WaterUnless otherwise indicated,referenceto water shall
10、be understood to mean reagent water conformingto Specification D 1193,Type I or Type II.6.3 Barium Chloride Solution(100 g/L)Dissolve 100 g ofbarium chloride(BaCl22H2O)in water and dilute to 1 L.6.4 n-Heptane.6.5 HydrochloricAcid(relativedensity1.19)Concentrated hydrochloric acid(HCl).6.6 Nitric Aci
11、d(relative density 1.42)Concentrated nitricacid(HNO3).6.7 Silver Nitrate Solution(100 g/L)Dissolve 100 g ofsilver nitrate(AgNO3)in water and dilute to 1 L.7.Procedure7.1 In a 250-mL separatory funnel,shake thoroughly 100mL(100 cm3)of the oil test specimen with 75 mL of water at95C.Allow to separate,
12、then draw off the water layer into a250-mL beaker.7.1.1 In case the separated water is not clear,filter it througha 10-cm diameter qualitative filter paper into a 250-mL beaker.1This test method is under the jurisdiction of ASTM Committee D27 onElectrical Insulating Liquids and Gases and is the dire
13、ct responsibility of Subcom-mittee D27.06on Chemical Test.Current edition approved Oct.10,2001.Published December 2001.Originallypublished as D 878 46 T.Last previous edition D 878 96a.2Annual Book of ASTM Standards,Vol 11.01.3Reagent Chemicals,American Chemical Society Specifications,AmericanChemic
14、al Society,Washington,DC.For suggestions on the testing of reagents notlisted by the American Chemical Society,see Analar Standards for LaboratoryChemicals,BDH Ltd.,Poole,Dorset,U.K.,and the United States Pharmacopeiaand National Formulary,U.S.Pharmaceutical Convention,Inc.(USPC),Rockville,MD.1Copyr
15、ight ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959,United States.The filtrate is then used for tests.As a check on the filter paper,75 mL of hot water,passed through the paper prior to filteringthe separated water,should give negative tests for chloridesand sul
16、fates.7.1.2 In the case of high-viscosity polybutene,dilute the100-mL sample with an equal amount of n-heptane.Stir untilthe test specimen is completely dissolved,transfer the solutionto a 500-mL separatory funnel,and proceed in accordance with7.1.NOTE2Polybutenes with a viscosity of 7 3 104m2/s at 100C canbe accommodated.Polybutenes with viscosities greater than 7 3 104m2/s at 100C have not been evaluated.7.2 Pour 15 mL of the separated water layer into a clean testtube,add a few drops of HNO3,