1、Designation:D 4305 98a(Reapproved 2004)e1An American National StandardStandard Test Method forFilter Flow of Aviation Fuels at Low Temperatures1This standard is issued under the fixed designation D 4305;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(e)indicates an editorial change since the last revision or reapproval.e1NOTEWarning notes were editorially moved into the standard text in May 2004.INTRODUCTIONThis test met
3、hod describes a procedure for determining the simulated freezing point for aviationturbine fuels using an automated apparatus.The results from this test method have been found to beequivalent to Test Method D 2386,except for liquids which have a viscosity of more than 5 mm2/s(cSt)at 20C(see Test Met
4、hod D 445),which can give a higher(warmer)result than Test MethodD 2386.The procedure can also be used to investigate the formation of wax crystals or the cold flowproperties of other products.1.Scope1.1 This test method covers the determination of lowtemperature flow behavior,through a screen-type
5、test filter,ofaviation turbine fuels,which can contain separated solids aswax.1.2 Procedure A employs a 26-m test filter and is therecommended procedure.Some existing instruments are fittedwith a 42-m filter,and Procedure B is retained to enable theircontinued use.1.3 The use of ProcedureA(26-m test
6、 filter)with fuels thathave a viscosity of greater than 5.0 mm2/s(cSt)at 20C,asdetermined by Test Method D 445,can affect the precision andthe simulated freezing point obtained on such fuels and cangive a higher(warmer)result than the conventional freezingpoint obtained by Test Method D 2386.NOTE1Th
7、e principle of this test method relies on flow through afine-mesh test filter,and,hence,the result can be affected by the viscosityof the sample.When using Procedure A,a no-flow condition is reachedwhen crystals block the test filter or the viscosity exceeds about 14 mm2/s(cSt);sample with a viscosi
8、ty of greater than 5 mm2/s(cSt)at 20C mayexceed the 14-mm2/s(cSt)threshold at a temperature before crystals areformed.If viscosity affects the result before crystals are formed,then thereported value of the no-flow temperature of the sample will always bewarmer than the actual freezing point,and the
9、refore fail-safe and anindicator of possible flow anomalies at low temperature.1.4 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 determi
10、ne the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2D 445 Test Method for Kinematic Viscosity of Transparentand Opaque Liquids(the Calculation of Dynamic Viscos-ity)D 1655 Specification for Aviation Turbine FuelsD 2386 Test Method for Freezing Point
11、 of Aviation FuelsD 4057 Practice for Manual Sampling of Petroleum andPetroleum Products3.Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 flow pointrepresents the temperature correspondingto the unblockage of a test filter that previously was blocked byseparated solids.3.1.2 no-f
12、low pointrepresents the temperature corre-sponding to a specified degree of blockage of a test filter byseparated solids.4.Summary of Test Method4.1 A 5-mL specimen of fuel is subjected to a programmedtemperature cycle while a pump maintains an oscillating flowat constant rate across a metal mesh te
13、st filter.As thetemperature falls,separated wax tends to restrict the test filter1This 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 May 1,2004.Publish
14、ed May 2004.Originallyapproved in 1983.Last previous edition approved in 1998 as D 4305 98a.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 Summar
15、y page onthe ASTM website.1Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959,United States.causing an increase in pressure.When this pressure exceeds1.33 kPa for more than 0.95 s,the no-flow point is indicatedand the cooling cycle is stopped.The pump cont
16、inues tooperate and exert pressure as the fuel specimen is warmed.Atthe point when the test filter is unplugged and pressure fallsbelow 1.33 kPa for more than 0.95 s,the flow point is indicatedand the temperature of the specimen displayed and held.5.Significance and Use5.1 The lowest temperature at which aviation fuels remainfree of solid hydrocarbon crystals,which may restrict the flowof fuel through filters in an aircraft fuel system,is a key safetyparameter in the specification and use of fue
