1、Designation: D7686 11Standard Test Method forField-Based Condition Monitoring of Soot in In-ServiceLubricants Using a Fixed-Filter Infrared (IR) Instrument1This standard is issued under the fixed designation D7686; the number immediately following the designation indicates the year oforiginal adopti
2、on 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 test method pertains to field-based monitoring ofsoot in diesel crank
3、case engine oils as well as in other types ofengine oils where soot may contaminate the lubricant as aresult of a blow-by due to incomplete combustion of fuels. It isapplicable to oils having soot levels of up to 12%.1.2 This test method uses filter-based infrared technologyfor monitoring of soot bu
4、ild-up in in-service petroleum andhydrocarbon-based lubricants as a result of normal machineryoperation. Soot levels in engine oils rise as soot particlescontaminate the oil as a result of exhaust gas recirculation fromblow-by. This test method is designed as a fast, simple and fieldcapable spectros
5、copic check for soot in in-servicehydrocarbon-based lubricants with the objective of helpingdiagnose the operational condition of the machine based onmeasuring the level of soot in the oil.1.3 This test method is intended as a field test only, andshould be treated as such. Critical applications shou
6、ld uselaboratory based methods, such as Thermal GravimetricAnaly-sis (TGA) described in Test Method D5967, Annex A4.1.4 Acquisition of spectral data for measuring soot inin-service oil and lubricant samples with the use of a fixed-filter IR instrument is described in this test method. Calibrationaga
7、inst prepared soot standards is also described.NOTE 1It is not the intent of this test method to establish orrecommend normal, cautionary, warning or alert limits for any machinery.Such limits should be established in conjunction with advice and guidancefrom the machinery manufacturer and maintenanc
8、e group.1.5 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.6 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 establ
9、ish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D5967 Test Method for Evaluation of Diesel Engine Oils inT-8 Diesel EngineD6299 Practice for Applying Statistical Quality Assuranceand Contr
10、ol Charting Techniques to Evaluate AnalyticalMeasurement System PerformanceD7418 Practice for Set-Up and Operation of Fourier Trans-form Infrared (FT-IR) Spectrometers for In-Service OilCondition MonitoringE131 Terminology Relating to Molecular SpectroscopyE2412 Practice for Condition Monitoring of
11、In-ServiceLubricants by Trend Analysis Using Fourier TransformInfrared (FT-IR) Spectrometry3. Terminology3.1 DefinitionsFor definitions of terms relating to infraredspectroscopy used in this test method, refer to TerminologyE131.3.2 DefinitionsFor definition of terms related to in-serviceoil conditi
12、on monitoring, refer to Practice D7418.4. Summary of Test Method4.1 This test method uses filter-based infrared spectrometryto monitor levels of soot in in-service petroleum and hydro-carbon based lubricants. The test method is meant to serve asa field-based method to provide an indicator of soot le
13、vel. Awell homogenized sample of oil is applied to a HorizontalAttenuated Total Reflectance (HATR) crystal. Infrared light istotally internally reflected through the HATR crystal and thenpassed through a broadband infrared filter centered on 3.9 m.The amount of infrared light reaching a detector is
14、converted to1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.96 on In-Service Lubricant Testing and Condition Monitoring Services.Current edition approved June 15, 2011. Published August 2011. DO
15、I:10.1520/D768611.2For 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.1Copyright ASTM International, 100 Barr Har
16、bor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.a soot concentration via a calibration curve generated from theinstrument response on various soot standards.5. Significance and Use5.1 This test method provides a simple field-based tech-nique for condition monitoring of soot i
17、n in-service lubricantsassociated with combustion engines, machinery, and equip-ment used in industry and by the military. Critical applicationsshould use laboratory based test methods, such as ThermalGravimetric Analysis (TGA) described in Test Method D5967,Annex A4. Infrared spectroscopy is a well
18、 established labora-tory method for evaluating soot levels in lubricants. This testmethod can be used to monitor soot build-up in lubricants andcan indicate whether soot has accumulated to an extent whichcould significantly degrade the performance of the oil. Highsoot content can compromise lubrican
19、t performance and causefilter and oil passage blockage. Soot concentration should beconsidered in conjunction with data from other conditionmonitoring tests as described in Practice E2412 to determinewhether the oil should be replaced to minimize machinery wearor failure, or both.6. Interferences6.1
20、 Some types of dirt or wear debris may cause a positivebias. In most cases the bias will be small and will likely alsoaffect Thermal Gravimetric Analysis (TGA) as described inTest Method D5967.6.2 Large amounts of free water in an oil sample may causea positive bias.7. Apparatus7.1 Filter Based Infr
21、ared Spectrometer:7.1.1 Infrared SpectrometerThe type of apparatus suitablefor this test method consists of a tungsten source, a 4 reflectioncubic zirconia horizontal attenuated total reflectance cell, aninfrared filter paired to a pyroelectric detector, an A/D con-verter and a microprocessor capabl
22、e of storing an internalcalibrations and converting instrument response into sootconcentration.7.1.2 Infrared Filter SpecificationsA broadband infraredfilter with a peak wavelength centered between 3.9 to 4.0 m,and a filter half width of 0.15 6 0.05 m shall be used.7.1.3 Other spectrometer configura
23、tions may provide ad-equate results; however the precision and bias data listed withthis test method was collected based on these apparatusspecifications. Any modifications may result in precision andor bias that differ from the numbers listed in this test method.8. Reagents and Materials8.1 Calibra
24、tion StandardsCalibration standards shallconsist of unused and sootfree 15w-40 diesel motor oiladulterated with various concentrations of sub micron particlesize, high structure carbon black dispersed in the oil and mixedthoroughly. The resulting soot concentration shall be deter-mined by Thermal Gr
25、avimetricAnalysis (TGA) as described inTest Method D5967. Five standards uniformly covering arange of approximately 0 to 12% soot are required. Precisioninformation for Thermal Gravimetric Analysis (TGA) in ac-cordance with Test Method D5967 can be found in Annex A1.9. Sampling, Test Specimens, and
26、Test Units9.1 General Requirements:9.1.1 It is recommended that in-service oil or lubricantsamples to be analyzed by this test method are sampled usingprocedures outlined in Practice D7418.9.1.2 Protect samples from excessive temperatures prior totesting.9.1.3 Do not test samples stored in leaky con
27、tainers. Discardand obtain a new sample if leaks are detected.9.2 When analyzing samples using this test method, shakethe sample vigorously until the sample is adequately homog-enized and no sediment is adhered to the bottom or sides of thevessel.10. Preparation of Apparatus10.1 Before use, the inst
28、rument needs to be calibratedaccording to the procedure described in Section 11. Thiscalibration can be performed by the instrument manufacturerprior to delivery of the instrument to the end user.10.2 Before analyzing samples, the instrument should beallowed to warm up for at least1htoensure the ana
29、lyzer isstabilized.10.3 Before use, the instrument should be qualified byrunning quality control check samples consisting of a knownsoot concentration as determined by Test Method D5967 thatspan the range that the instrument is calibrated in. Thesesamples should consist of at least one sample in the
30、 bottomthird of the range, one sample in the middle third of the rangeand one sample in the top third of the range. Apply the controlcharting procedures described in Practice D6299 to establishthat the analyzer is in-statistical-control. Any system that isfound to be out of statistical control canno
31、t be used until theroot cause(s) of out-of-control is identified and corrected.11. Calibration and Standardization11.1 Calibration StandardsRefer to 8.1 for calibrationstandard description.11.2 Calibration:11.2.1 Equilibrate all samples to the temperature of thelaboratory (15C to 27C) prior to analy
32、sis11.2.2 Allow the instrument to warm up for at least one hourbefore attempting a calibration.11.2.3 Calibration standards should be run in a randomizedorder.11.2.4 Clean the HATR sample crystal of any residual oil orother contamination by applying about 1 mL of unused andsootfree oil to the crysta
33、l and wiping across the crystal in onedirection with a disposable wipe. Avoid rubbing back and forthsince this can recontaminate the crystal.11.2.5 Introduce approximately 1 mL of unused, sootfreeoil sample of the same type as the oils to be analyzed to theinstrument, ensuring that the crystal is co
34、mpletely covered withsample. Remove any bubbles from the sample if needed.11.2.6 Obtain a baseline detector response (zero) accordingto the manufacturers instructions with the unused oil sampleon the crystal. A zero should be obtained before the first useand once every two hours the instrument is in
35、 use.11.2.7 Wipe the sample off using a disposable wipe once thesampling is complete.D7686 11211.2.8 Shake the first calibration standard vigorously untilthe sample is adequately homogenized and no sediment isadhered to the bottom or sides of the vessel.11.2.9 Introduce approximately 1 mL of the fir
36、st calibrationstandard to the instrument, ensuring that the crystal is com-pletely covered with sample. Remove any bubbles from thesample if needed by piercing the bubbles with the sampleapplicator.11.2.10 Obtain an infrared detector response according tothe manufacturers instructions and divide thi
37、s by the baselinedetector response. The ratio may be calculated internally by theinstrument. The acquisition of a detector response should beinitiated within 10 s of placing the sample on the crystal inorder to reduce any errors due to sample settling.11.2.11 Record the resulting response for later
38、use in deter-mining the calibration curve.11.2.12 Wipe the sample off using a disposable wipe, thenapply about 1 mL of unused and sootfree oil to the crystal andwipe across the crystal in one direction with a disposable wipeto clean the crystal of any soot residue.Avoid rubbing back andforth since t
39、his can recontaminate the crystal.11.2.13 Repeat 11.2.7-11.2.11 for each calibration standard.Standards should be run in a randomized order.11.2.14 Repeat steps 11.2.3-11.2.12 twice more, so that eachcalibration standard is run three times. Average the threeinstrument responses recorded for each cal
40、ibration standardand compute the difference from the mean for each of the threeresponses. If a response differs by more than 0.1x+2mAUfrom the mean response for that standard, where x is theparticular instrument response value, then the value should beexcluded as an outlier and another standard run
41、at thatconcentration level.11.2.15 After removal of outliers, compute the averageresponse at each concentration level. These concentrationversus response values should determine a point to point curve,with a linear fit applied between adjacent points. This curveshould be used to convert instrument r
42、esponse values to weight% soot. The point to point curve may be generated by theinstrument microprocessor.12. Procedure12.1 Equilibrate the samples to between 15C and 27Cbefore analysis.12.2 Clean the HATR sample crystal of any residual oil orother contamination by applying about 1 mL of unused ands
43、ootfree oil to the crystal and wiping across the crystal in onedirection with a disposable wipe. Avoid rubbing back and forthsince this can recontaminate the crystal.12.3 Introduce approximately 1 mL of an unused, sootfreesample of the same type as the oils to be analyzed to theinstrument, ensuring
44、that the crystal is completely covered withsample. Remove any bubbles from the sample if needed bypiercing the bubbles with the sample applicator.12.4 Obtain a baseline detector response (zero) according tothe manufacturers instructions with the unused oil sample onthe crystal. A zero should be obta
45、ined before the first use andonce every two hours the instrument is in use.12.5 Wipe the sample off using a disposable wipe once thesampling is complete.12.6 Shake unknown samples vigorously until the sample isadequately homogenized and no sediment is adhered to thebottom or sides of the vessel.12.7
46、 Introduce approximately 1 mL of unknown sample tothe instrument, ensuring that the entire crystal surface iscovered with sample. Remove any bubbles from the sample ifneeded by piercing the bubbles with the sample applicator.12.8 Obtain an infrared detector response and divide this bythe baseline de
47、tector response according to the manufacturersinstructions. The ratio may be calculated internally by theinstrument. The acquisition of a detector response should beinitiated within 10 seconds of placing the sample on the crystalin order to reduce any errors due to sample settling.12.9 Determine the
48、 soot concentration according to thepoint-to-point calibration generated in Section 11. This may beautomatically computed by an instrument microprocessor.12.10 Wipe the sample off using a disposable wipe, thenapply about 1 mL of unused and sootfree oil to the crystal andwipe across the crystal in on
49、e direction with a disposable wipeto clean the crystal of any soot residue.Avoid rubbing back andforth since this can recontaminate the crystal.13. Report13.1 Report the following information:13.1.1 Weight % Soot by Test Method D7686, to the nearest0.1%.14. Precision and Bias14.1 PrecisionThe repeatability has been determined tobe:0.016 X1.2wt % (1)where X is the calculated soot concentration in weight %. Thereproducibility of this test method is being determined and willbe available on or before December 1, 2014.15. Keywords15.1 condition monitoring; diesel
