1、Designation: D7647 10Standard 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; the number immediat
2、ely 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. Scope1.1 This tes
3、t 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)to 200m(c)with the upper limit being dependent on the specificautomatic particle count
4、er 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 beencalibrated in accor
5、dance 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 viscosity range i
6、s up to 1000 mm2/s 40C.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 dilution are not suita
7、blefor analysis using this test method.1.6 The test method is specific to automatic particlecounters that use the light extinction principle and are cali-brated according to the latest revision of ISO 11171.1.7 The values stated in SI units are to be regarded asstandard. No other units of measuremen
8、t are included in thisstandard.1.8 This test method 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 determine the applica-bility of regulatory limita
9、tions prior to use.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 Mineral InsulatingOil Using Automatic Optical Particle Co
10、unters2.2 ISO Standards:3ISO 3722 Hydraulic Fluid PowerFluid Sample ContainersQualifying and Controlling Cleaning MethodsISO 4406 Hydraulic Fluid PowerFluidsMethod for Cod-ing Level of Contamination by Solid ParticlesISO 11171 Hydraulic Fluid PowerCalibration of Auto-matic Particle Counters for Liqu
11、ids3. Terminology3.1 DefinitionsFor the purposes of this test method, thefollowing definitions apply:3.1.1 coincidence, nthe presence of more than one par-ticle in the sensing zone of a particle analyzer at the same time,causing incorrect sizing and incorrect counting of the particlepresent. The coi
12、ncidence 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 11171.3.1.2 diluent, na solvent listed in Annex A1, Table A1.1,having viscosity less than 10 mm2/s at 40C that
13、 is physically1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.96.05 on In-Service Lubricants Particle Counting Practices and Techniques.Current edition approved July 1, 2010. Published September
14、 2010. DOI:10.1520/D764710.2For 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 onthe ASTM website.3Available from American National
15、Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.and chemically compatible with the apparatus used and easilysoluble at room temperature with
16、 the sample lubricant orhydraulic fluid.3.1.3 emulsified water, nwater that exists in oil betweenthe states of fully dissolved and phase-separated. An emulsi-fying agent in the oil causes the two immiscible liquids tocoexist in a heterogeneous mixture.3.1.4 free water, nwater that exists in a separa
17、te phase inan oil sample. This occurs when the water content of the oilexceeds the water holding capacity of the oil.3.1.5 interfering soft particles, nan undissolved, dis-persed material (such as an additive) within an oil blend orsubstance that is formed during the service life of an oil blend.3.1
18、.5.1 DiscussionWhen these substances are present in asample and not completely solubilized, they are likely to becounted by an optical particle counter in a similar manner todirt and wear metal particles, air bubbles, and free waterdroplets.3.1.6 ISO Codes, na standard classification for coding thel
19、evel of contamination by solid particles.3.1.6.1 DiscussionThis code simplifies the reporting ofparticle count data by converting the number of particles permL into three classes covering $4m(c), $6m(c)and $14m(c). ISO 4406 classifications are used as an option to reportresults for this test method.
20、3.1.7 particle size, m(c), ndiameter of a circle with anarea equivalent to the projected area of a particle passingthrough the detecting cell in accordance with ISO 11171.3.1.8 particle size cumulative count, ntotal number ofparticles with sizes greater than a specified particle size (forexample, $4
21、m(c), $6m(c), $10 m(c), $14 m(c), $21m(c), $38 m(c), etc.).NOTE 3All particle counts are expressed on per 1 mL basis.3.1.9 soot-in-oil, na sub-micron particulate product ofincomplete combustion commonly found in in-service dieselengine crankcase oil.3.1.10 water-masking diluent, na particular kind o
22、f dilu-ent capable of dissolving otherwise immiscible substances suchas water or soft particles in the sample lubricant or hydraulicfluid. See 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 con
23、tainer.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 repeat agitation anddegassing).4.8 Obtain particle counts in triplicate (for sample andmethod blank).4.9 Analyze data and conduct validity checks.4.10 Report r
24、esults.5. Significance and Use5.1 This test method is intended for use in analyticallaboratories including onsite in-service oil analysis laborato-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 a
25、ccelerate the degradation of theoil. Hard particles in the oil originate from a variety of sourcesincluding generation from within an operating 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
26、contaminants can cause filter blockagesand hard particles can have a serious impact on the life ofpumps, pistons, gears, bearings, and other 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
27、cleaning thefluid, determining if off-line recirculating filtration is needed toclean up the fluid system, or aiding in the decision of whetheror not a fluid change is required.5.5 To accurately measure hard particle contamination lev-els, it is necessary to negate the particle counts contributed by
28、the presence of small levels of free water. This method includesa process by which this can be accomplished using a water-masking diluent technique whereby water droplets of a sizebelow the target level are finely distributed.5.6 Certain additives or additive by-products that are semi-insoluble or i
29、nsoluble in oil, namely the polydimethylsiloxanedefoamant additive and oxidation by-products, are known tocause light scattering in automatic particle counters, which inturn causes falsely high counts. These and similar materials arecommonly termed “soft particles” (see 3.1.5) and are notknown to di
30、rectly increase wear and erosion within an operat-ing system. The contribution of these particles to the particlesize cumulative count is negated 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 o
31、ptical particle counting results.6. InterferencesNOTE 4This section is consistent with the interferences described inTest Method D6786.6.1 Dirty environmental conditions and poor handling tech-niques can easily contaminate the sample or test specimen, orboth. Care shall be taken to ensure test resul
32、ts are not biased byintroduced particles.6.2 Air bubbles in the oil may be counted as particles givingfalse positive readings. 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 g
33、enerally becounted as particles.NOTE 5Free or emulsified water interference presented can be ne-gated by using the water-masking diluent as described in this test method.6.4 Excessive concentrations of particles in the oil willcause coincidence or electronic saturation errors, or both.Limits are det
34、ermined by ISO 11171 and are generally suppliedD7647 102by the instrument manufacturer. These errors may be avoidedby increasing the dilution ratio with the diluent used in this testmethod.6.5 Odd-shaped particles and fibers may be classified withincorrect calculated particle size, depending on thei
35、r orienta-tion as they pass through the sensing zone of the instrument.6.6 Dye-in-oil is used by some lubricant manufacturers todistinguish 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 possi
36、ble interferencesfor dye-in-oil by testing a sample of filtered, dyed, lubricant. Ifthe automatic particle counter yields unusual results 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 iti
37、mpractical to test in-service diesel engine lubricants, espe-cially when soot level exceeds 1 %. This is not normally aproblem for natural gas and gasoline engine oils. Howeverheavy duty diesel engine oils typically produce excessive sootfor most automatic particle counters. The coincident, opaque,s
38、oot particles reduce light transmission and produce very highfalse particle counts.6.8 Solid lubricants, such as molybdenum disulfide orgraphite are used in some lubricating oils, especially forextreme pressure applications. These materials are typicallyused at levels high enough to render the fluid
39、 opaque or tocause coincidence errors due to high particle concentrations inthe detector. Even if these factors can be overcome withsufficient dilution, increases in particle counts are difficult todetermine with adequate precision due to the inherently highparticle counts in these fluids.6.9 Specim
40、en bottles shall not be reused. This is a source ofcross-contamination interference.7. Apparatus7.1 Liquid Automatic Particle Counter (APC), liquid opticalparticle counter based on the light extinction principle. Theinstrument shall be capable of recording the size and number ofparticles as they pas
41、s across the detector. The particle countershall include a sampling apparatus that automatically deliversa predetermined volume of specimen 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 Sh
42、aker, paint shaker, table shaker, or othermechanical device to vigorously agitate sample containers.7.4 Ultrasonic Bath, rated at 3000 to 10 000 W/m2. Thisbath aids in the removal of air bubbles generated in the sampleduring the agitation process while also working to suspendparticles in the sample
43、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 dilution orfluid transfer with a pipette is desired. Pipettes made ofgraduated glass or disposable polyethylene. Any glasswareused shall be cleaned and verified in ac
44、cordance withISO 3722.7.7 Density Meter, with an accuracy of 0.01 g/cm3,ifthemass dilution method is used.7.8 Filter Apparatus, for filtering the diluent. There is norequirement for the apparatus itself but it shall be capable ofproducing acceptably clean diluent as necessary. Take appro-priate safe
45、ty precautions in handling low flash materials.7.9 Vacuum Degassing Apparatus, capable of pulling fullvacuum on the sample container in 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 ac
46、cordance with ISO 3722.7.11 Sample Container, a container used for collecting theneat sample per 9.1 and 9.2, or for diluting sample specimens.7.11.1 Sample containers shall not be reused.7.11.2 Recommended containers are cylindrical specimenbottles (or jars) typically made of polypropylene, polysty
47、rene,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 requiremen
48、ts and APC designmay call for substantially smaller or much larger samplecontainers.7.11.4 After performing any cleaning procedures, thesample containers shall meet the cleanliness criteria of contrib-uting less than 1 % of the total particles expected in thecleanest sample.7.11.5 Sample containers
49、shall be compatible with fluid andable to withstand the temperature of the fluid when collectingthe sample. Sample containers with certified cleanliness levels(for example, “ultra clean”) may be used to collect samples forparticle counting.7.12 Specimen Bottle, or sample specimen bottle, a samplecontainer used for diluting at least a portion of a sample. Aspecimen bottle shall meet the same criteria as the samplecontainer (7.11.1-7.11.5).7.13 Filters, to be used with filter apparatus (see 7.8).Recommended filters are cellulose or polycarbonat
