1、Designation: D7596 10D7596 14Standard Test Method forAutomatic Particle Counting and Particle ShapeClassification of Oils Using a Direct Imaging IntegratedTester1This standard is issued under the fixed designation D7596; the number immediately following the designation indicates the year oforiginal
2、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. Scope Scope*1.1 This test method covers the determination of particle concent
3、ration, particle size distribution, particle shape, and sootcontent for new and in-service oils used for lubrication and hydraulic systems by a direct imaging integrated tester.1.1.1 The test method is applicable to petroleum and synthetic based fluids. Samples from 2 to 150 mm2/s at 40C may beproce
4、ssed directly. Samples of greater viscosity may be processed after solvent dilution.1.1.2 Particles measured are in the range from 4 m to 70 m 70 m with the upper limit dependent upon passing througha 100 m 100 m mesh inlet screen.1.1.3 Particle concentration measured may be as high as 5,000,0005 00
5、0 000 particles per mL without significant coincidenceerror.1.1.4 Particle shape is determined for particles greater than approximately 20 m in length. Particles are categorized into thefollowing categories: sliding, cutting, fatigue, nonmetallic, fibers, water droplets, and air bubbles.1.1.5 Soot i
6、s determined up to approximately 1.5 % by weight.1.1.6 This test method uses objects of known linear dimension for calibration.1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.3 This standard does not purport to address a
7、ll of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D445 Test Method for
8、Kinematic Viscosity of Transparent and Opaque Liquids (and Calculation of Dynamic Viscosity)D2896 Test Method for Base Number of Petroleum Products by Potentiometric Perchloric Acid TitrationD4057 Practice for Manual Sampling of Petroleum and Petroleum ProductsD4175 Terminology Relating to Petroleum
9、, Petroleum Products, and LubricantsD4177 Practice for Automatic Sampling of Petroleum and Petroleum ProductsD5185 Test Method for Multielement Determination of Used and Unused Lubricating Oils and Base Oils by InductivelyCoupled Plasma Atomic Emission Spectrometry (ICP-AES)D5967 Test Method for Eva
10、luation of Diesel Engine Oils in T-8 Diesel EngineD6304 Test Method for Determination of Water in Petroleum Products, Lubricating Oils, and Additives by Coulometric KarlFischer TitrationD6595 Test Method for Determination of Wear Metals and Contaminants in Used Lubricating Oils or Used Hydraulic Flu
11、ids byRotating Disc Electrode Atomic Emission SpectrometryD7279 Test Method for Kinematic Viscosity of Transparent and Opaque Liquids by Automated Houillon ViscometerE2412 Practice for Condition Monitoring of In-Service Lubricants by TrendAnalysis Using Fourier Transform Infrared (FT-IR)Spectrometry
12、1 This test method is under the jurisdiction of ASTM Committee D02 on Petroleum Products Products, Liquid Fuels, and Lubricants and is the direct responsibility ofSubcommittee D02.96 on In-Service Lubricant Testing and Condition Monitoring Services.Current edition approved May 1, 2010June 1, 2014. P
13、ublished August 2010July 2014. Originally approved in 2010. Last previous edition approved in 2010 as D7596 10.DOI: 10.1520/D759610.10.1520/D7596-14.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standa
14、rdsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible t
15、o adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright
16、 ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1G40 Terminology Relating to Wear and Erosion2.2 ISO Standards:3ISO 12103-1 1997 Road vehicles - Test dust for filter evaluation - Part 1: Arizona test dustVehiclesTest Dust for FilterEvaluationPa
17、rt 1: Arizona Test DustISO 4406 Hydraulic fluid power Fluids Method for coding level of contamination by solid particlesFluid PowerFluidsMethod for Coding Level of Contamination by Solid Particles2.3 SAE Standards:4SAE AS 4059 Aerospace Fluid Power Cleanliness Classification for Hydraulic Fluids3. T
18、erminology3.1 Definitions of Terms Specific to This Standard:3.1.1 contaminant particles, nparticles introduced from an extraneous source into the lubricant of a machine or engine.3.1.2 direct imaging integrated tester, nan instrument for counting particles as they flow through a cell by means of im
19、aging;instrument may also determine particle shape and fluid viscosity.3.1.3 ISO Codes, nstandard method for coding the level of contamination by solid particles. This code simplifies the reportingof particle count data by converting the number of particles per mL into three classes covering 4 m, 6
20、4 m, 6 m, and 14 14 m. ISO 4406 classifications are used as an option to report results for this test method.3.1.4 new oil, noil taken from the original manufacturers packaging, prior to being added to the machinery. E24123.1.5 particle size, circular diameter, m, ndiameter of a circle with an area
21、equivalent to the projected area of a particlepassing through the direct imaging integrated tester flow cell.3.1.6 soft particles, nparticles present in the sample that are related to undissolved oil additives or additive by-products.Without dilution, at room temperature these particles are likely t
22、o be counted by an optical particle counter in a similar mannerto dirt and wear metal particles, air bubbles, and free water droplets. They are not considered contaminants as they are eitherpurposefully left undissolved, or are not harmful to the fluid system, or both.3.1.7 soot, nin internal combus
23、tion engines, sub-micron size particles, primarily carbon, created in the combustion chamberas products of incomplete combustion. D41753.1.8 wear, ndamage to a solid surface, usually involving progressive loss or displacement of material, due to relative motionbetween that surface and a contacting s
24、ubstance or substances. D4175, G403.1.9 wear particles, nparticles generated from wearing surfaces of a machine or engine.4. Summary of Test Method4.1 Lubricant samples are acquired periodically from a machine or engine being monitored. Samples are taken using cleanreceptacles in order to avoid alte
25、ring the sample by method or container.4.2 Particles are counted and sized by drawing oil through a flow cell. Seeprocessing a sample through an Fig. 1. The cell isilluminated by a pulsed laser. The duration of the pulse is sufficiently fast to freeze the motion of the particles in the cell. The pul
26、sefrequency is 30appropriate particle sizing instrument. Sample size is instrument dependent. The instrument determines the size andshape of each particle detected in the sample as described in Section 1 Hz. Images of the particles flowing through the cell aremagnified by 4 using a lens between the
27、cell and the CCD video chip onto which the images of the particles are focused. Softwarecounts and sizes each particle. Sizing is done by comparison to objects of known linear dimension. The number of particles permL is determined by dividing particle counts by the volume of oil examined. Each image
28、 taken corresponds to a small volume ofoil equal to the image area, which is 1600 1200 m, multiplied by the cell thickness, nominally 100 m.The actual cell thickness,to the closest m for each cell, is provided by the manufacturer and is entered into the software for theof this test method.Adjustable
29、 cell gap instruments are set at a fixed gap width that allows for comprehensive analysis. Gap of 100 to 300 m is acommon distance, however instruments may vary and other gap distances may be employed as long as there is no restriction ofparticle flow into the measurement zone. See Fig. 1purpose of
30、calculating the volume of oil examined for each sample. The totaloil volume examined is the volume per image multiplied by the number of images collected4.3 The direct imaging integrated tester software performs particle shape recognition instrument calculates the shape of allparticles 20 m by using
31、 a neural network. An algorithm 20 m in size. The instrument software sorts particles into thefollowing categories: cutting, fatigue, severe sliding, nonmetallic, fibers, air bubbles and water droplets. fibers. Air bubbles and3 Available from International Organization for Standardization (ISO), 1,
32、ch. de la Voie-Creuse, Case postale 56, CH-1211, Geneva 20, Switzerland, http:/www.iso.ch.4 Available from SAE International (SAE), 400 Commonwealth Dr., Warrendale, PA 15096-0001, http:/aerospace.sae.org.D7596 142water droplets 20 m are 20 m must be eliminated from the particle counting results. re
33、sults by analysis or treatment. Furtherinformation regarding wear particle shape recognition may be found in AndersonsAnderson report.5.4.4 Nonmetallic particles are recognized by their partial transparency. Nonmetallic particles, in thin sections, do not block light,as do metallic particles. Theref
34、ore, particles displaying transparent interior pixels are classified as nonmetallic. Nontransparentparticles are sorted into one of three metallic categories, namely, cutting, sliding, and fatigue.4.5 Cutting wear particles are recognized by their elongated, curved, or curly shape.4.6 Sliding wear p
35、articles are recognized by being longer than wide, often with straight edges.4.7 Fatigue particles are recognized by being more or less as long as they are wide and often with jagged, irregular edges.4.8 Fibers are recognized by their elongated shape and by partial transparency indicating nonmetalli
36、c composition.4.9 Air bubbles are dark round circles, either completely dark or with small bright centers.4.10 Water droplets are dark round circles with large bright centers. The difference in appearance between air bubbles and waterdroplets is due to the much different refractive index of each. Wh
37、en present in oil, air bubbles refract much of the light passingthrough them away from the direction of transmission, whereas water droplets, having a refractive index more nearly equal to thatof oil, allow much of the light incident upon them to transmit through them to the CCD video chip.4.11 Soot
38、 is measured by performing an optical extinction measurement with reference to new oil.Absorbance of the laser lightis calculatedmeasured and calibration is made to diesel engine oil samples with known percentage of soot as determined by thermalgravimetric analysis in accordance with Test Method D59
39、67, Annex A4.4.12 Condition alerts and alarms, based on trend and level, can be issued for the system being monitored according to particlecount, size distribution, types of particles recognized and soot content.5. Significance and Use5.1 This test method is intended for use in analytical laboratori
40、es including on-site in-service oil analysis laboratories. Periodicsampling and analysis of lubricants have long been used as a means to determine overall machinery health. Atomic emission5 Anderson, D.P., Wear Particle Atlas (Revised), Prepared for Advanced Technology Office, Support Equipment Engi
41、neering Department, Naval Air Engineering Center,Lakehurst, NJ, 08733, 28 June 1982, Report NAEC 92 163, approved for public release, distribution unlimited.Anderson, D., Wear Particle Atlas (Revised), PreparedforAdvanced Technology Office, Support Equipment Engineering Department, NavalAir Engineer
42、ing Center, Lakehurst, NJ, 08733, 28 June 1982, Report NAEC 92 163,approved for public release, distribution unlimited.FIG. 1 Schematic of Direct Imaging Integrated TesterTesterD7596 143spectroscopy (AES) is often employed for wear metal analysis (Test Methods D5185 and D6595). A number of physical
43、propertytests complement wear metal analysis and are used to provide information on lubricant condition (Test Methods D445, D2896,D6304, and D7279). Molecular spectroscopy (Practice E2412) provides direct information on molecular species of interestincluding additives, lubricant degradation products
44、 and contaminating fluids such as water, fuel and glycol. The direct Directimaging integrated tester providestesters provide complementary information on particle count, particle size, particle type, and sootcontent.5.2 Particles in lubricating and hydraulic oils are detrimental because they increas
45、e wear, clog filters and accelerate oildegradation.5.3 Particle count may aid in assessing the capability of a filtration system to clean the fluid, determine if off-line recirculatingfiltration is needed to clean the fluid, or aid in the decision whether or not to change the fluid.5.4 An increase i
46、n the concentration and size of wear particles is indicative of incipient failure or component change out.Predictive maintenance by oil analysis monitors the concentration and size of wear particles on a periodic basis to predict failure.5.5 High soot levels in diesel engine lubricating oil may indi
47、cate abnormal engine operation.6. Interferences6.1 Dirty environmental conditions and poor handling techniques can easily contaminate the sample. Care must be taken toensure test results are not biased by introduced particles.6.2 Air bubbles 20 m may be counted as particles giving false positive rea
48、dings. Air bubbles 20 m are recognized andautomatically eliminated from the count. Mixing or agitating the sample introduces air bubbles into the oil, but these readilydissipate with ultra-sonication or vacuum degassing.6.3 Water droplets 20 m may be counted as particles giving false positive readin
49、gs. If water droplets 20 m are detectedin a sample by the direct imaging integrated tester, there is reason to suspect water droplets 20 m are present and have spuriouslyincreased particle count. Small amounts of water in the sample may be negated by the use of water masking solvent. See AppendixX1.6.4 Certain additives or additive by-products that are not fully dissolved in the oil, most notably polydimethylsiloxanedefoamant additive, are known to be present as soft particles that are not contami
