1、Designation:D 2755 90(Reapproved 1997)e1An American National StandardStandard Test Method ofSampling and Reduction to Test Weight of Electrical GradeMagnesium Oxide1This standard is issued under the fixed designation D 2755;the number immediately following the designation indicates the year oforigin
2、al 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.e1NOTEKeywords were added in October 1997.1.Scope1.1 This test method covers techn
3、iques for sampling largelots of magnesium oxide(MgO)and reducing representativesamples to test weight.1.2 The values stated in acceptable metric units are to beregarded as the standard.The values in parentheses may beapproximate.1.3 This standard does not purport to address the safetyproblems associ
4、ated with its use.It is the responsibility of theuser of this standard to establish appropriate safety and healthpractices and determine the applicability of regulatory limita-tions prior to use.2.Referenced Documents2.1 ASTM Standards:D 2772 Test Method for Sieve Analysis of Electrical GradeMagnesi
5、um Oxide23.Apparatus3.1 Splitter,consisting of a series of chutes fed by a singlehopper.The chutes are so placed that each alternate chutedischarges to the same side of the sampler.The spacing ofplates must remain 1.6 to 3.2 mm(116to18in.).The splittershould be capable of obtaining homogeneous split
6、s.33.2 Scoop.3.3 BlenderAny commercially acceptable blender with a45 kg(100 lb)minimum capacity.44.Procedure4.1 For Reduction of Bulk(Approximately 45 kg(100lb)Quantities:4.1.1 Blend the entire content of one or more standardcontainers for a minimum of 15 min in a suitable sized blender.4.1.2 Remove
7、 1 L of material in a minimum of five scoopsfrom the various parts of the blender.4.2 For Reduction of 1 L Samples:4.2.1 Pour the sample evenly into the splitter,across thesplitter opening.4.2.2 When the entire sample has been poured through,tapthe side of the splitter to make sure no build-up has o
8、ccurred.Discard the content of one pan.4.2.3 If a smaller sample is required,repeat the splittingprocess.5.Precision5.1 When samples from both sides of the splitter are testedin accordance with Test Method D 2772,the percent weightretained on any given sieve shall be within 3.0%of theaverage percent
9、 weight retained on that sieve.6.Keywords6.1 electrical grade;magnesium oxide;sampling and reduc-tion;test weight1This method is under the jurisdiction of ASTM Committee D-9 on Electricaland Electronic Insulating Materials and is the direct responsibility of SubcommitteeD09.14 on Electric Heating Un
10、it Insulation.Current edition approved July 27,1990.Published September 1990.Originallypublished as D 2755 68.Last previous edition D 2755 68(1977).2Annual Book of ASTM Standards,Vol 10.02.3Splitters available from C.E.Tyler Industrial Products,8200 Tyler Blvd.,Mentor,OH or Microsplitter(Model SS162
11、)Carpco Research and Engineering,4120 Haines St.,P.O.Box 3272,Jacksonville,FL have been found satisfactory forthis method.4The MacLellan batch mixer manufactured by Daffin Manufacturing Co.,Lancaster,PA(formerly Anglo American Co.)has been found satisfactory for thismethod.1Copyright ASTM Internatio
12、nal,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959,United States.NOTICE:This standard has either been superceded and replaced by a new version or discontinued.Contact ASTM International(www.astm.org)for the latest information.The American Society for Testing and Materials takes no
13、 position respecting the validity of any patent rights asserted in connectionwith any item mentioned in this standard.Users of this standard are expressly advised that determination of the validity of any suchpatent rights,and the risk of infringement of such rights,are entirely their own responsibi
14、lity.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 be addressed to AST
15、M Headquarters.Your comments will receive careful consideration at a meeting of the responsibletechnical committee,which you may attend.If you feel that your comments have not received a fair hearing you should make yourviews known to the ASTM Committee on Standards,at the address shown below.This s
16、tandard is copyrighted byASTM,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA19428-2959,United States.Individual reprints(single or multiple copies)of this standard may be obtained by contacting ASTM at the above address or at610-832-9585(phone),610-832-9555(fax),or serviceastm.org(e-mail);or through the ASTM website(www.astm.org).D 27552NOTICE:This standard has either been superceded and replaced by a new version or discontinued.Contact ASTM International(www.astm.org)for the latest info
