1、Designation:D674902(Reapproved 2012)Standard Test Method forPour Point of Petroleum Products(Automatic Air PressureMethod)1This standard is issued under the fixed designation D6749;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the
2、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.INTRODUCTIONThis test method covers an alternative procedure for the determination of pour point of petroleumproducts using an
3、 automatic apparatus.1.Scope1.1 This test method covers the determination of pour pointof petroleum products by an automatic apparatus that applies aslightly positive air pressure onto the specimen surface whilethe specimen is being cooled.1.2 This test method is designed to cover the range oftemper
4、atures from 57 to+51C;however,the range oftemperatures included in the(1998)interlaboratory test pro-gram only covered the temperature range from 51 to 11C.1.3 Test results from this test method can be determined ateither 1 or 3C testing intervals.1.4 This test method is not intended for use with cr
5、ude oils.NOTE1The applicability of this test method on residual fuel sampleshas not been verified.For further information on the applicability,refer to13.4.1.5 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.6 This standard doe
6、s 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 Standard
7、s:2D97 Test Method for Pour Point of Petroleum ProductsD4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD4177 Practice for Automatic Sampling of Petroleum andPetroleum Products2.2 Energy Institute Standard:IP 15 Test Method for Pour Point of Petroleum Products33.Terminology3.1 De
8、finitions:3.1.1 pour point,nin petroleum products,lowest tempera-ture at which movement of the test specimen is observed underprescribed conditions of test.3.2 Definitions of Terms Specific to This Standard:3.2.1 air pressure,nregulated slightly positive air pres-sure gently applied onto the specime
9、n surface in the airtighttest jar that causes upward movement of the specimen in thecommunicating tube,which has one end inserted into the testspecimen and the other end at atmospheric pressure.3.2.2 no-flow point,nin petroleum products,temperatureof the test specimen at which a wax crystal structur
10、e of the testspecimen or viscosity increase,or both,impedes movement ofthe surface of the test specimen under the conditions of the test.3.2.2.1 DiscussionThe no-flow point occurs when,uponcooling,the formation of wax crystal structures or viscosityincrease,or both,has progressed to the point where
11、the appliedobservation device no longer detects movement under theconditions of the test.The preceding observation temperature,at which flow of the test specimen is last observed,is the pourpoint.4.Summary of Test Method4.1 After inserting the test jar containing the specimen intothe automatic pour
12、point apparatus and initiating the test1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.07 on Flow Properties.Current edition approved Nov.1,2012.Published November 2012.Originallyapproved in 200
13、2.Last previous edition approved in 2007 as D674902(2007).DOI:10.1520/D6749-02R12.2For 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 ont
14、he ASTM website.3Available from Energy Institute,61 New Cavendish St.,London,WIG 7AR,U.K.,http:/www.energyinst.org.uk.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 program,the specimen is automatically heated to the desig-nated temperat
15、ure and then cooled at a controlled rate.Attemperature intervals of 1 or 3C,depending on the selectionmade by the user prior to the test,a slightly positive airpressure is gently applied onto the surface of the specimenwhich is contained in an airtight test jar equipped with acommunicating tube.Sinc
16、e one end of the communicating tubeis inserted into the specimen while the other end is maintainedat atmospheric pressure,a small amount of downward move-ment or deformation of the specimen surface,as a result of theapplication of air pressure,is observed by means of upwardmovement of the specimen in the communicating tube.Thisupward movement of the specimen is detected by a pressuresensor which is installed at the atmospheric end of thecommunicating tube.The lowest temperature at which defor-ma
