1、Designation:D6940/D6940M20Standard Practice forMeasuring Sifting Segregation Tendencies of Bulk Solids1This standard is issued under the fixed designation D6940/D6940M;the number immediately following the designation indicates theyear of original adoption or,in the case of revision,the year of last
2、revision.A number in parentheses indicates the year of lastreapproval.A superscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope*1.1 This practice covers an apparatus and procedure forsimulating the segregation tendencies of bulk solids by meansof the sifting
3、mechanism.1.2 Temperature-and humidity-sensitive bulk solids mayneed to be tested at different temperatures and moisturecontents,as would happen in an industrial environment.1.3 The maximum particle size should be limited to 3 mm18in.,to reduce the likelihood of binding the slide gate.1.4 This stand
4、ard is not applicable to all bulk solids andsegregation mechanisms:while sifting is a common segrega-tion mechanism experienced by many bulk solids,othersegregation mechanisms not evaluated by this standard mightinduce segregation in practice.Practice D6941 covers anothercommon mechanism:fluidizatio
5、n.1.5 The extent to which segregation will occur in anindustrial situation is not only a function of the bulk solid andits tendency to segregate,but also the handling equipment(forexample,bin design),process(for example,transfer rates),andenvironment.1.6 UnitsThe values stated in either SI units or
6、inch-pound units are to be regarded separately as standard.Thevalues stated in each system may not be exact equivalents;therefore,each system shall be used independently of the other.Combining values from the two systems may result in noncon-formance with the standard.1.7 All observed and calculated
7、 values shall conform to theguidelines for significant digits and rounding established inPractice D6026.1.8 This practice offers a set of instructions for performingone or more specific operations.This document cannot replaceeducation or experience and should be used in conjunction withprofessional
8、judgment.Not all aspects of this practice may beapplicable in all circumstances.This ASTM standard is notintended to represent or replace the standard of care by whichthe adequacy of a given professional service must be judged,nor should this document be applied without consideration ofa projects ma
9、ny unique aspects.The word“Standard”in thetitle of this document means only that the document has beenapproved through the ASTM consensus process.1.9 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 standar
10、d to establish appro-priate safety,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.10 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Pr
11、inciples for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:2D653 Terminology Relating to Soil,Rock,and ContainedFluidsD2216 Test Methods for Laboratory Det
12、ermination of Water(Moisture)Content of Soil and Rock by MassD3740 Practice for Minimum Requirements for AgenciesEngaged in Testing and/or Inspection of Soil and Rock asUsed in Engineering Design and ConstructionD6026 Practice for Using Significant Digits in GeotechnicalDataD6941 Practice for Measur
13、ing Fluidization Segregation Ten-dencies of Powders3.Terminology3.1 Definitions:3.1.1 For common definitions of terms in this standard,referto Terminology D653.3.1.2 funnel flow pattern,nin storing,handling and pro-cessing bulk solids using industrial equipment,a flow sequencein a bin or hopper char
14、acterized by having some particlesmoving while other particles are stagnant during discharge.1This practice is under the jurisdiction of ASTM Committee D18 on Soil andRock and is the direct responsibility of Subcommittee D18.24 on Characterizationand Handling of Powders and Bulk Solids.Current editi
15、on approved Jan.1,2020.Published January 2020.Originallyapproved in 2003.Last previous edition approved in 2018 as D694018.DOI:10.1520/D6940_D6940M-20.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandard
16、svolume information,refer to the standards Document Summary page onthe ASTM website.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by