1、Designation: D 7483 08Standard Test Method forDetermination of Dynamic Viscosity and Derived KinematicViscosity of Liquids by Oscillating Piston Viscometer1This standard is issued under the fixed designation D 7483; the number immediately following the designation indicates the year oforiginal adopt
2、ion 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 covers the measurement of dynamicviscosity and derivatio
3、n of kinematic viscosity of liquids, suchas new and in-service lubricating oils, by means of anoscillating piston viscometer.1.2 This test method is applicable to Newtonian and non-Newtonian liquids; however the precision statement was de-veloped using Newtonian liquids.1.3 The range of dynamic visc
4、osity covered by this testmethod is from 0.2 mPas to 20 000 mPas (which is approxi-mately the kinematic viscosity range of 0.2 mm2/s to 22 000mm2/s for new oils) in the temperature range between 40 to190C; however the precision has been determined only fornew and used oils in the range of 1.434 mPas
5、 to 154.4 mPasat temperatures of 40 and 100C (as stated in the precisionsection).1.4 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.5 This standard does not purport to address all of thesafety concerns, if any, associated wit
6、h 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 limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 445 Test Method for Kinematic Viscosity of Transparentand Opaque
7、Liquids (and Calculation of Dynamic Viscos-ity)D 2162 Practice for Basic Calibration of Master Viscom-eters and Viscosity Oil StandardsD 4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD 4177 Practice for Automatic Sampling of Petroleum andPetroleum ProductsD 5967 Test Method for
8、 Evaluation of Diesel Engine Oils inT-8 Diesel EngineD 6792 Practice for Quality System in Petroleum Productsand Lubricants Testing Laboratories2.2 ISO Standards:3ISO/EC 17025 General Requirements for the Competenceof Testing and Calibration Laboratories2.3 NIST Standard:4NIST Technical Note 1297 Gu
9、ideline for Evaluating andExpressing the Uncertainty of NIST Measurement Results3. Terminology3.1 Definitions:3.1.1 dynamic viscosity (h), nthe ratio between the ap-plied shear stress and rate of shear of a liquid.3.1.1.1 DiscussionIt is sometimes called the coefficient ofdynamic viscosity or, simpl
10、y, viscosity. Thus, dynamic viscos-ity is a measure of the resistance to flow or to deformation ofa liquid under external shear forces.3.1.1.2 DiscussionThe term dynamic viscosity can alsobe used in a different context to denote a frequency-dependantquantity in which shear stress and shear rate have
11、 a sinusoidaltime dependence.3.1.2 kinematic viscosity (n), nthe ratio of the dynamicviscosity (h) to the density (r) of a liquid.3.1.2.1 DiscussionFor gravity flow under a given hydro-static head, the pressure head of a liquid is proportional to itsdensity, (r). Therefore the kinematic viscosity, (
12、n), is a measureof the resistance to flow of a liquid under gravity.3.1.3 rate of shear (shear rate), n in liquid flow, thevelocity gradient across the liquid.3.1.4 shear stress, nthe force per unit area in the directionof the flow.3.1.4.1 DiscussionThe SI unit for shear stress is thepascal (Pa).1Th
13、is 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 Dec. 15, 2008. Published February 2009.2For referenced ASTM standards, visit the ASTM website, www.ast
14、m.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 International Organization for Standardization (ISO), 1, ch. dela Voie-Creuse, Case postale 56, CH-1211, Gen
15、eva 20, Switzerland, http:/www.iso.ch.4Available from http:/physics.nist.gov/ccu/Uncertainty/index.html.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.1.5 density (r), nmass per unit volume.3.2 Definitions of Terms Specific to Thi
16、s Standard:3.2.1 oscillating piston viscometer, na device that mea-sures the travel time of a piston driven electromagnetically intostationary oscillating motion through a liquid at a controlledforce in order to determine the dynamic viscosity of the liquid.4. Summary of Test Method4.1 A specimen of
17、 sample is placed in the thermallycontrolled measurement chamber where the piston resides. Thepiston is driven into oscillatory motion within the measurementchamber by a controlled magnetic field. Once the sample is atthe test temperature, as determined by the temperature detector,the piston is prop
18、elled repeatedly through the liquid (by themagnetic field). A shear stress (ranging from 5 Pa to 750 Pa) isimposed on the liquid under test due to the piston travel. Thedynamic viscosity is determined by measuring the averagetravel time of the piston. The kinematic viscosity is derived byadditionall
19、y measuring the ratio between the up and downtravel times. This information is then applied to a calibrationcurve using liquids of known viscosity to calculate the dynamicviscosity and kinematic viscosity of the liquid. See Fig. 1.5. Significance and Use5.1 Many petroleum products, as well as non-pe
20、troleummaterials, are used as lubricants for bearings, gears, compres-sor cylinders, hydraulic equipment, etc. Proper operation ofthis equipment depends upon the viscosity of these liquids.5.2 Oscillating piston viscometers allow viscosity measure-ment of a broad range of materials including transpa
21、rent,translucent and opaque liquids. The measurement principle andstainless steel construction makes the Oscillating Piston Vis-cometer resistant to damage and suitable for portable opera-tions. The measurement itself is automatic and does not requirean operator to time the oscillation of the piston
22、. The electro-magnetically driven piston mixes the sample while under test.The instrument requires a sample volume of less than 5 mLandtypical solvent volume of less than 10 mL which minimizescleanup effort and waste.6. Apparatus6.1 Oscillating Piston Viscometer:566.1.1 The oscillating piston viscom
23、eter (see Fig. 2) com-prises a measurement chamber and calibrated piston capable ofmeasuring the dynamic viscosity within the limits of precisiongiven in Section 16.6.1.2 PistonFree moving, magnetically driven bodywithin a Oscillating Piston Viscometer which is used formeasuring the viscosity of liq
24、uids. Individual pistons are sizedto measure specific viscosity ranges by varying the sensorannulus. See Table 1 for the selection of the piston accordingto the viscosity range.6.1.3 Measurement ChamberLocation within OscillatingPiston Viscometer where piston motion (through the liquidunder test) oc
25、curs due to an imposed electromagnetic field. SeeFig. 1.6.1.4 ElectronicsCapable of controlling the electromag-netic field to propel and detect the travel time of the piston witha discrimination of 0.01 s or better and uncertainty within60.07 %. The travel time is calibrated to be between 0.4 s and6
26、0 s, at a distance of 5 mm.5The Oscillating Piston Viscometer is covered by a patent. Interested parties areinvited to submit information regarding the identification of an alternative to thispatented item to the ASTM International headquarters. Your comments will receivecareful consideration at a m
27、eeting of the responsible technical committee, whichyou may attend.6The sole sources of supply for the apparatus known to the committee at thistime is Cambridge Viscosity Inc., 101 Station Landing, Medford, MA 02155(). If you are aware of alternative suppliers, pleaseprovide this information to ASTM
28、 International Headquarters. Your comments willreceive careful consideration at a meeting of the responsible technical committee,which you may attend.FIG. 1 Cross Sectional View of Measurement ChamberD74830826.1.5 Temperature Controlled JacketSufficient for main-taining measurement chamber temperatu
29、re within 60.06C.6.1.6 Temperature Measuring DeviceIndustrial platinumresistance thermometer (IPRT) or equivalent sensor with amaximum permissible error of 60.02C. It is recommended,that the temperature measuring device be verified with anindependent, calibrated temperature probe at the test tempera
30、-ture.6.2 Temperature Regulation System:6.2.1 Any liquid bath or thermoelectric means for regulatingthe jacket temperature.6.2.2 The temperature control must be such that the tem-perature of the measurement chamber is held within 60.06Cof the desired measurement temperature.6.3 Sample Introduction M
31、echanismA syringe, micropi-pette, or flow-through adapter for introducing between 3.2 mLand 5 mL, inclusive by pressure, into the measurementchamber.7. Reagents and Materials7.1 Certified viscosity reference standards shall be certifiedby a laboratory that has been shown to meet the requirementsof I
32、SO/EC 17025 by independent assessment. Viscosity stan-dards shall be traceable to master viscometer proceduresdescribed in Practice D 2162.7.2 The uncertainty of the certified viscosity referencestandard shall be stated for each certified value (k = 2, 95 %confidence). See ISO/EC 17025 or NIST TN 12
33、97.7.2.1 The certified viscosity reference should have a pub-lished viscosity in accordance with Test Method D 445 orequivalent means that is close to that of the liquids being testedat the test temperature. For example, if intended measurementsare to be made from 5-25 mPas at 100C, then a reference
34、 oilviscosity of 15 mPas at 100C would be appropriate.7.3 Cleaning solvents miscible with the sample and chemi-cally compatible with the wetted viscometer components (suchas alcohols, toluene, etc.). These wetted components aretypically 316L and 430 Stainless Steel.7.4 Quality control (QC) liquid si
35、milar to 7.1, but withviscosity values internally certified as noted in 12.2.8. 8. Sampling, Samples, and Test Units8.1 Ensure that the sample is homogenous. Engine samplingis generally specified in the test method, for example TestMethod D 5967. When applicable, refer to Practice D 4057(manual) or
36、Practice D 4177 (automatic) for proper samplingtechniques.9. Preparation of Apparatus9.1 Place the viscometer on a stable surface.9.2 Operate the unit according to the procedure in Section13.9.3 Verify calibration accuracy by testing a reference stan-dard or QC liquid at the test temperature. Follow
37、 the procedurein Section 13.FIG. 2 Viscometer with ElectronicsTABLE 1 Viscosity Ranges of Oscillating Viscometer PistonsMinimum Viscosity (mPas ) Maximum Viscosity (mPas ) Piston Designation Nominal Piston Diameter (mm) Recommended Sample Volume (mL)0.02 2 SP20 7.87 3.2 - 50.25 5 SP50 7.83 3.2 - 50.
38、5 10 SP11 7.81 3.2 - 51 20 SP21 7.76 3.5 - 52.5 50 SP51 7.68 3.5 - 55 100 SP12 7.62 3.5 - 510 200 SP22 7.54 3.5 - 525 500 SP52 7.34 3.5 - 550 1000 SP13 7.21 4.0 - 5100 2000 SP23 6.96 4.0 - 5250 5000 SP53 6.27 4.0 5500 10000 SP14 6.05 4.0 - 51000 20000 SP24 5.72 4.0 - 5D748308310. Calibration and Sta
39、ndardization10.1 Calibrate according to manufacturers instructions toobtain a calibration curve (using two test liquids with refer-enced viscosity values near, but within, the extremes of thepiston range being used).10.2 Certified Viscosity Standards may be used as confir-matory checks on the proced
40、ure in the laboratory. This proce-dure is outlined in Section 13. If the dynamic viscosity result,at the calibration test point, does not agree with the certifiedvalue within the limits of precision in Section 16, each step inthe procedure should be rechecked, as well as the temperaturemeasuring dev
41、ice and viscometer calibration, to locate thesource of error. If the source is not detected, consult themanufacturer.11. Sample Conditioning11.1 Shake all new and used oil samples using the followingprocedure.11.1.1 Ensure cap is tight on the container.11.1.2 Shake vigorously by hand for 30 s. Wait
42、10 s, orlonger if needed, for air bubbles to dissipate.11.1.3 A specimen of the sample shall be taken by pipette,pouring or pumping. Suspected nonhomogeneous samplesmust be conveyed for analysis promptly following the shakingand dissipation procedure of step 11.1.2.12. Quality Control/Quality Assura
43、nce (QC/QA)12.1 Confirm proper performance of the instrument and thetest procedure by analyzing reference oil as QC sample.12.2 If suitable reference oil is not available, prepare a QCsample by replicate analyses of a batch of oil sample. Thenstatistically analyze the data to assign a mean value and
44、uncertainty limit to the sample.12.3 When QC/QA protocols are already established in thetesting facility, these may be used to confirm the reliability ofthe test result.12.4 When there is no QC/QA protocol established in thetesting facility, guidance may be obtained from PracticeD 6792.13. Procedure
45、13.1 Verify or set the temperature control settings, as testedwith the control standard, so the viscometer temperature readsthe desired set point 60.06C while the piston is in motion.13.2 Remove the piston and clean the specimen from themeasurement chamber as described in the viscometer manual.13.3
46、Load the measurement chamber with sample using thevolume listed in Table 1 related to the piston size being usedfor the viscosity range anticipated. To minimize contamination,and if sample volume allows, pre-wet the chamber and pistonwith the sample material and dry wipe with a lint free cloth.13.4
47、Load the measurement chamber with a clean piston.The piston size should be selected such that the measuredviscosity is between the minimum and maximum viscosityvalues listed in Table 1. If the reported result is outside of thisrange, the measurement shall be repeated using the appropriatepiston size
48、.13.5 Start the reporting software in accordance with manu-facturers instructions, which in turn will:13.5.1 Allow the sample to equilibrate in the measurementchamber for at least 2 min while the piston is oscillating.13.5.2 Ensure that temperature stability is within the crite-rion set in 6.2.13.5.
49、3 Measure the upward and downward piston traveltimes for each cycle and compute viscosity until the standarddeviation as percent of mean, over the previous 20 dynamicviscosity computations, is less than 0.6%.13.6 Record the average result from the last 20 computa-tions.14. Calculation and Interpretation14.1 The calculation of dynamic viscosity and kinematicviscosity are computed and displayed automatically by theapparatus.15. Report15.1 Dynamic Viscosity result in mPas to three significantfigures, as displayed by the ap
