1、Designation: D7647 10 (Reapproved 2018)Standard Test Method forAutomatic Particle Counting of Lubricating and HydraulicFluids Using Dilution Techniques to Eliminate theContribution of Water and Interfering Soft Particles by LightExtinction1This standard is issued under the fixed designation D7647; t
2、he number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the 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.1.
3、 Scope1.1 This test method covers the determination of particleconcentration and particle size distribution in new and in-service oils used for lubrication and hydraulic purposes.1.2 Particles considered are in the range from 4 m(c)to200 m(c)with the upper limit being dependent on the specificautoma
4、tic particle counter being used.NOTE 1For the purpose of this test method, water droplets not maskedby the diluent procedure are detected as particles, and agglomeratedparticles are detected and reported as a single larger particle.NOTE 2The subscript(c)is used to denote that the apparatus has beenc
5、alibrated in accordance with ISO 11171. This subscript(c)strictly onlyapplies to particles up to 50 m.1.3 Lubricants that can be analyzed by this test method arecategorized as petroleum products or synthetic based products,such as: polyalpha olefin, polyalkylene glycol, or phosphateester. Applicable
6、 viscosity range is up to 1000 mm2/s at 40 C.This procedure may be appropriate for other petroleum andsynthetic based lubricants not included in the precision state-ment.1.4 Samples containing visible particles may not be suitablefor analysis using this test method.1.5 Samples that are opaque after
7、dilution are not suitablefor analysis using this test method.1.6 The test method is specific to automatic particle coun-ters that use the light extinction principle and are calibratedaccording to the latest revision of ISO 11171.1.7 The values stated in SI units are to be regarded asstandard. No oth
8、er units of measurement are included in thisstandard.1.8 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, health, and environmental practices and deter-mine the
9、 applicability of regulatory limitations prior to use.1.9 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issue
10、d by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD4177 Practice for Automatic Sampling of Petroleum andPetroleum ProductsD6786 Test Method for Particle Count in
11、 Mineral InsulatingOil Using Automatic Optical Particle Counters2.2 ISO Standards:3ISO 3722 Hydraulic fluid powerFluid samplecontainersQualifying and controlling cleaning methodsISO 4406 Hydraulic fluid powerFluidsMethod for cod-ing level of contamination by solid particlesISO 11171 Hydraulic fluid
12、powerCalibration of automaticparticle counters for liquids3. Terminology3.1 Definitions:3.1.1 For the purposes of this test method, the followingdefinitions apply:1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products, Liquid Fuels, and Lubricants and is the direct re
13、sponsibility ofSubcommittee D02.96.05 on In-Service Lubricants Particle Counting Practices andTechniques.Current edition approved April 1, 2018. Published May 2018. Originallyapproved in 2010. Last previous edition approved in 2010 as D7647 10. DOI:10.1520/D7647-10R18.2For referenced ASTM standards,
14、 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 onthe ASTM website.3Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New
15、York, NY 10036, http:/www.ansi.org.Copyright 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 Pri
16、nciples for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.13.1.2 coincidence, nthe presence of more than one particlein the sensing zone of a particle analyzer at the same time,causing incorrec
17、t sizing and incorrect counting of the particlepresent. The coincidence limit of the counter is determined bythe maximum acceptable concentration of particles in thesensing zone and is supplied by the instrument manufacturer.Refer to Section 3.4 in ISO 11171.3.1.3 diluent, na solvent listed in Annex
18、 A1, Table A1.1,having viscosity less than 10 mm2/s at 40 C that is physicallyand chemically compatible with the apparatus used and easilysoluble at room temperature with the sample lubricant orhydraulic fluid.3.1.4 emulsified water, nwater that exists in oil betweenthe states of fully dissolved and
19、 phase-separated. An emulsi-fying agent in the oil causes the two immiscible liquids tocoexist in a heterogeneous mixture.3.1.5 free water, nwater that exists in a separate phase inan oil sample. This occurs when the water content of the oilexceeds the water holding capacity of the oil.3.1.6 interfe
20、ring soft particles, nan undissolved, dispersedmaterial (such as an additive) within an oil blend or substancethat is formed during the service life of an oil blend.3.1.6.1 DiscussionWhen these substances are present in asample and not completely solubilized, they are likely to becounted by an optic
21、al particle counter in a similar manner todirt and wear metal particles, air bubbles, and free waterdroplets.3.1.7 ISO Codes, na standard classification for coding thelevel of contamination by solid particles.3.1.7.1 DiscussionThis code simplifies the reporting ofparticle count data by converting th
22、e number of particles permL into three classes covering 4m(c), 6m(c)and14 m(c). ISO 4406 classifications are used as an option toreport results for this test method.3.1.8 particle size, m(c),ndiameter of a circle with anarea equivalent to the projected area of a particle passingthrough the detecting
23、 cell in accordance with ISO 11171.3.1.9 particle size cumulative count, ntotal number ofparticles with sizes greater than a specified particle size (forexample, 4m(c), 6m(c), 10 m(c), 14 m(c),21 m(c), 38 m(c), etc.).NOTE 3All particle counts are expressed on per 1 mL basis.3.1.10 soot-in-oil, na su
24、b-micron particulate product ofincomplete combustion commonly found in in-service dieselengine crankcase oil.3.1.11 water-masking diluent, na particular kind of di-luent capable of dissolving otherwise immiscible substancessuch as water or soft particles in the sample lubricant orhydraulic fluid. Se
25、e Annex A1, Table A1.1.4. Summary of Test Method4.1 Inspect sample.4.2 Agitate sample.4.3 Obtain aliquot from homogeneous sample if not dilutingin original container.4.4 Dilute with appropriate diluent for the sample type.4.5 Agitate diluted sample.4.6 Degas sample.4.7 Begin testing within 90 s (or
26、repeat agitation and degas-sing).4.8 Obtain particle counts in triplicate (for sample andmethod blank).4.9 Analyze data and conduct validity checks.4.10 Report results.5. Significance and Use5.1 This test method is intended for use in analyticallaboratories including onsite in-service oil analysis l
27、aborato-ries.5.2 Hard particles in lubricating or fluid power systems havea detrimental effect on the system as they cause operatingcomponents to wear and also accelerate the degradation of theoil. Hard particles in the oil originate from a variety of sourcesincluding generation from within an opera
28、ting fluid system orcontamination, which may occur during the storage and han-dling of new oils or via ingress into an operating fluid system.5.3 High levels of contaminants can cause filter blockagesand hard particles can have a serious impact on the life ofpumps, pistons, gears, bearings, and othe
29、r moving parts byaccelerating wear and erosion.5.4 Particle count results can be used to aid in assessing thecapability of the filtration system responsible for cleaning thefluid, determining if off-line recirculating filtration is needed toclean up the fluid system, or aiding in the decision of whe
30、theror not a fluid change is required.5.5 To accurately measure hard particle contaminationlevels, it is necessary to negate the particle counts contributedby the presence of small levels of free water. This methodincludes a process by which this can be accomplished using awater-masking diluent tech
31、nique whereby water droplets of asize below the target level are finely distributed.5.6 Certain additives or additive by-products that are semi-insoluble or insoluble in oil, namely the polydimethylsiloxanedefoamant additive and oxidation by-products, are known tocause light scattering in automatic
32、particle counters, which inturn causes falsely high counts. These and similar materials arecommonly termed “soft particles” (see 3.1.6) and are notknown to directly increase wear and erosion within an operat-ing system. The contribution of these particles to the particlesize cumulative count is nega
33、ted with this method.5.7 The use of dilution in this test method counteractsviscosity effects for highly viscous oils that impact the accu-racy of automatic optical particle counting results.6. InterferencesNOTE 4This section is consistent with the interferences described inTest Method D6786.6.1 Dir
34、ty environmental conditions and poor handling tech-niques can easily contaminate the sample or test specimen, orboth. Care shall be taken to ensure test results are not biased byintroduced particles.D7647 10 (2018)26.2 Air bubbles in the oil may be counted as particles givingfalse positive readings.
35、 Mixing or agitating the sample intro-duces bubbles into the oil, but these readily dissipate withsonication or vacuum degassing.6.3 Suspended or free water in the oil will generally becounted as particles.NOTE 5Free or emulsified water interference presented can benegated by using the water-masking
36、 diluent as described in this testmethod.6.4 Excessive concentrations of particles in the oil willcause coincidence or electronic saturation errors, or both.Limits are determined by ISO 11171 and are generally suppliedby the instrument manufacturer. These errors may be avoidedby increasing the dilut
37、ion ratio with the diluent used in this testmethod.6.5 Odd-shaped particles and fibers may be classified withincorrect calculated particle size, depending on their orienta-tion as they pass through the sensing zone of the instrument.6.6 Dye-in-oil is used by some lubricant manufacturers todistinguis
38、h certain lubricant types or brands. It is unusual forthat dye to have a discernible impact on particle count data.Nonetheless, it is worthwhile to evaluate possible interferencesfor dye-in-oil by testing a sample of filtered, dyed, lubricant. Ifthe automatic particle counter yields unusual results
39、or if itreports an optical warning message, then this may be anindication of this type of interference.6.7 Excessive soot-in-oil is an interference that makes itimpractical to test in-service diesel engine lubricants, espe-cially when soot level exceeds 1 %. This is not normally aproblem for natural
40、 gas and gasoline engine oils. Howeverheavy duty diesel engine oils typically produce excessive sootfor most automatic particle counters. The coincident, opaque,soot particles reduce light transmission and produce very highfalse particle counts.6.8 Solid lubricants, such as molybdenum disulfide orgr
41、aphite are used in some lubricating oils, especially forextreme pressure applications. These materials are typicallyused at levels high enough to render the fluid opaque or tocause coincidence errors due to high particle concentrations inthe detector. Even if these factors can be overcome withsuffic
42、ient dilution, increases in particle counts are difficult todetermine with adequate precision due to the inherently highparticle counts in these fluids.6.9 Specimen bottles shall not be reused. This is a source ofcross-contamination interference.7. Apparatus7.1 Liquid Automatic Particle Counter (APC
43、), liquid opticalparticle counter based on the light extinction principle. Theinstrument shall be capable of recording the size and number ofparticles as they pass across the detector. The particle countershall include a sampling apparatus that automatically deliversa predetermined volume of specime
44、n at a controlled flow rateto the sensing zone of the analyzer.7.2 Analytical Balance, for mass dilution, calibrated, with aresolution of 100 mg.7.3 Mechanical Shaker, paint shaker, table shaker, or othermechanical device to vigorously agitate sample containers.7.4 Ultrasonic Bath, rated at 3000 W m
45、2to 10 000 W m2.This bath aids in the removal of air bubbles generated in thesample during the agitation process while also working tosuspend particles in the sample and slow the settling process.7.5 Liquid Dispensers, fitted with 0.8 m or finer filter.7.6 Volumetric Pipette and Bulb, if volumetric
46、dilution orfluid transfer with a pipette is desired. Pipettes made ofgraduated glass or disposable polyethylene. Any glasswareused shall be cleaned and verified in accordance with ISO3722.7.7 Density Meter, with an accuracy of 0.01 g cm3,ifthemass dilution method is used.7.8 Filter Apparatus, for fi
47、ltering the diluent. There is norequirement for the apparatus itself but it shall be capable ofproducing acceptably clean diluent as necessary. Take appro-priate safety precautions in handling low flash materials.7.9 Vacuum Degassing Apparatus, capable of pulling fullvacuum on the sample container i
48、n a vacuum chamber (per12.4.1) or syringe degassing port (per 12.4.3) within time limitspecified.7.10 Glassware, any glassware used shall be cleaned andverified in accordance with ISO 3722.7.11 Sample Container, a container used for collecting theneat sample per 9.1 and 9.2, or for diluting sample s
49、pecimens.7.11.1 Sample containers shall not be reused.7.11.2 Recommended containers are cylindrical specimenbottles (or jars) typically made of polypropylene, polystyrene,PET, or glass with nominally flat bottoms, fitted with a suitablenon-shedding threaded cap.7.11.3 The dimensions and capacity of sample containersdepends on specimen requirements and APC design. Samplecontainers often have an approximate capacity of 125 mL.However individual specimen requirements and APC designmay call for substantially smaller or much larger sampl
