1、Designation: D7042 11aStandard Test Method forDynamic Viscosity and Density of Liquids by StabingerViscometer (and the Calculation of Kinematic Viscosity)1This standard is issued under the fixed designation D7042; the number immediately following the designation indicates the year oforiginal adoptio
2、n 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*1.1 This test method covers and specifies a procedure for theconcurrent measur
3、ement of both the dynamic viscosity, h, andthe density, r, of liquid petroleum products and crude oils, bothtransparent and opaque. The kinematic viscosity, n, can beobtained by dividing the dynamic viscosity, h, by the density,r, obtained at the same test temperature.1.2 The result obtained from th
4、is test method is dependentupon the behavior of the sample and is intended for applicationto liquids for which primarily the shear stress and shear rate areproportional (Newtonian flow behavior).1.3 While the precision has only been determined for baseoils in the viscosity range from 2.05 to 456 mPa
5、s at 40C andfrom 0.83 to 31.6 mPas at 100C and in the density range from0.82 to 0.92 g/cm3at 15C (see 15.5), the test method can beapplied to a wider range of materials, viscosity, density, andtemperature. For materials not listed in Precision and Bias(Section 15), the precision and bias may not be
6、applicable.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 with its use. It is theresponsibility of the user of this standard to est
7、ablish appro-priate safety and health practices and to determine theapplicability of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D445 Test Method for Kinematic Viscosity of Transparentand Opaque Liquids (and Calculation of Dynamic Viscos-ity)D2162 Practice for Basi
8、c Calibration of Master Viscometersand Viscosity Oil StandardsD2270 Practice for Calculating Viscosity Index from Kine-matic Viscosity at 40 and 100CD4052 Test Method for Density, Relative Density, and APIGravity of Liquids by Digital Density MeterD6299 Practice for Applying Statistical Quality Assu
9、ranceand Control Charting Techniques to Evaluate AnalyticalMeasurement System PerformanceD6300 Practice for Determination of Precision and BiasData for Use in Test Methods for Petroleum Products andLubricantsD6617 Practice for Laboratory Bias Detection Using SingleTest Result from Standard MaterialD
10、6708 Practice for StatisticalAssessment and Improvementof Expected Agreement Between Two Test Methods thatPurport to Measure the Same Property of a Material2.2 ISO Standards:3ISO 5725 Accuracy (trueness and precision) of measure-ment methods and resultsISO/IEC 17025 General Requirements for the Comp
11、etenceof Testing and Calibration Laboratories2.3 Other Documents:4NIST Technical Note 1297 Guideline for Evaluating andExpressing the Uncertainty of NIST Measurement Results3. Terminology3.1 Definitions:3.1.1 density (r), nmass per unit volume.3.1.2 dynamic viscosity (h), nthe ratio between the ap-p
12、lied shear stress and rate of shear of a liquid.3.1.2.1 DiscussionIt is sometimes called the coefficient ofdynamic viscosity or, simply, viscosity. Thus, dynamic viscos-ity is a measure of the resistance to flow or to deformation ofa liquid under external shear forces.3.1.2.2 DiscussionThe term dyna
13、mic viscosity can alsobe used in a different context to denote a frequency-dependentquantity in which shear stress and shear rate have a sinusoidaltime dependence.1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of
14、 SubcommitteeD02.07 on Flow Properties.Current edition approved Oct. 1, 2011. Published November 2011. Originallyapproved in 2004. Last previous edition approved in 2011 as D704211.DOI:10.1520/D7042-11a.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Ser
15、vice 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 York, NY 10036, http:/www.ansi.org.4Available from National Instit
16、ute of Standards and Technology (NIST), 100Bureau Dr., Stop 1070, Gaithersburg, MD 20899-1070, http:/www.nist.gov.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.1.3
17、 kinematic viscosity (n), nthe ratio of the dynamicviscosity (h) to the density (r) of a liquid.3.1.3.1 DiscussionFor gravity flow under a given hydro-static head, the pressure head of a liquid is proportional to itsdensity (r). Therefore the kinematic viscosity (n) is a measureof the resistance to
18、flow of a liquid under gravity.3.1.4 relative density (also called specific gravity (SG),nthe ratio of the density of a material at a stated temperatureto the density of a reference material (usually water) at a statedtemperature.4. Summary of Test Method4.1 The test specimen is introduced into the
19、measuring cells,which are at a closely controlled and known temperature. Themeasuring cells consist of a pair of rotating concentric cylin-ders and an oscillating U-tube. The dynamic viscosity isdetermined from the equilibrium rotational speed of the innercylinder under the influence of the shear st
20、ress of the testspecimen and an eddy current brake in conjunction withadjustment data. The density is determined by the oscillationfrequency of the U-tube in conjunction with adjustment data.The kinematic viscosity is calculated by dividing the dynamicviscosity by the density.5. Significance and Use
21、5.1 Many petroleum products, and some non-petroleummaterials, are used as lubricants and the correct operation ofthe equipment depends upon the appropriate viscosity of theliquid being used. In addition, the viscosity of many petroleumfuels is important for the estimation of optimum storage,handling
22、, and operational conditions. Thus, the accurate deter-mination of viscosity is essential to many product specifica-tions.5.2 Density is a fundamental physical property that can beused in conjunction with other properties to characterize boththe light and heavy fractions of petroleum and petroleumpr
23、oducts.5.3 Determination of the density or relative density ofpetroleum and its products is necessary for the conversion ofmeasured volumes to volumes at the standard temperature of15C.6. Apparatus6.1 Stabinger Viscometer5,66.1.1 Viscosity measurementThe Stabinger viscometeruses a rotational coaxial
24、 cylinder measuring system. The outercylinder (tube) is driven by a motor at a constant and knownrotational speed. The low-density inner cylinder (rotor) is heldin the axis of rotation by the centrifugal forces of the higherdensity sample and in its longitudinal position by the magnetand the soft ir
25、on ring. Consequently, the system works free ofbearing friction as found in rotational viscometers. A perma-nent magnet in the inner cylinder induces eddy currents in thesurrounding copper casing. The rotational speed of the innercylinder establishes itself as the result of the equilibriumbetween th
26、e driving torque of the viscous forces and theretarding eddy current torque. This rotational speed is mea-sured by an electronic system (Hall effect sensor) by countingthe frequency of the rotating magnetic field (see Fig. 1 and Fig.2, No. 2).6.1.2 Density MeasurementThe digital density analyzeruses
27、 a U-shaped oscillating sample tube and a system forelectronic excitation and frequency counting (see Fig. 2, No.3).6.1.3 Temperature ControlThe copper block surroundsboth the viscosity and the density measuring cell in a way thatboth cells are held at the same temperature. A thermoelectricheating a
28、nd cooling system (see Fig. 2, No. 1) ensures thetemperature stability of the copper block within 60.005Cfrom the set temperature at the position of the viscosity cellover the whole temperature range. The uncertainty (k = 2; 95 %confidence level) of the temperature calibration shall be nomore than 6
29、0.03C over the range from 15 to 100C. Outsidethis range the calibration uncertainty shall be no more than60.05C.6.1.4 The thermal equilibration time depends on the heatcapacity and conductivity of the liquid and on the differencebetween injection temperature and test temperature. Adequatetemperature
30、 equilibration of the test specimen is automaticallydetermined when successive viscosity values are constantwithin 60.07 % over 1 min and successive density values areconstant within 60.00003 g/cm3over 60 s.NOTE 1The Stabinger Viscometer, manufactured by Anton PaarGmbH, fulfills the stated requireme
31、nts when operated in the most precisemode of operation.6.2 Syringes, commercially available, at least 5 mL involume, with a Luer tip.All construction materials for syringesshall be fully compatible with all sample liquids and cleaningagents, which contact them.6.3 Flow-Through or Pressure Adapter, f
32、or use as analternative means of introducing the test specimen into themeasuring cells either by pressure or by suction, provided that5The Stabinger viscometer is covered by a patent. Interested parties are invitedto submit information regarding the identification of an alternative to this patentedi
33、tem to the ASTM International headquarters. Your comments will receive carefulconsideration at a meeting of the responsible technical committee, which you mayattend.6The sole source of supply of the apparatus known to the committee at this timeis Anton Paar GmbH, Anton-Paar-Str. 20, A-8054 Graz, Aus
34、tria. If you are aware ofalternative suppliers, please provide this information to ASTM Internationalheadquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend.FIG. 1 Viscosity CellD7042 11a2sufficient care and control is u
35、sed to avoid any bubbleformation in the test specimen. All construction materials foradaptors shall be fully compatible with all sample liquids andcleaning agents, which contact them.6.4 Autosampler, for use in automated injection analyses.The autosampler shall be designed to ensure the integrity of
36、 thetest specimen prior to and during the analysis and be equippedto transfer a representative portion of test specimen into themeasuring cells. The autosampler shall transfer the test speci-men from the sample vial to the measuring cells of theapparatus without interfering with the integrity of the
37、 testspecimen. The autosampler shall be able to mimic the proce-dure for sample handling as set forth in 11.1 and 11.2. Theautosampler may have heating capability as a means to lowerthe viscosity of the sample for filling the measuring cells.6.5 Screen, with an aperture of 75 m, to remove particlesf
38、rom the sample.6.6 Magnet, strong enough to remove iron fillings from thesample. Magnetic stirring rods are suitable.7. Reagents and Materials7.1 Sample Solvent, completely miscible with the sample.7.1.1 For most samples, a volatile petroleum spirit ornaphtha is suitable. If the solvent dries up wit
39、hout residues inan applicable time frame, the use of a separate drying solventis not required.7.1.2 For residual fuels, a prewash with an aromatic solventsuch as toluene or xylene may be necessary to remove asphalticmaterial.7.2 Drying Solvent, a volatile solvent miscible with thesample solvent (see
40、 7.1).7.2.1 Highly concentrated ethanol (96 % or higher) is suit-able.7.3 Dry Air or Nitrogen, for blowing the measuring cells.7.3.1 If the measuring cell temperature is below or near thedew point temperature of the ambient air, the use of anappropriate desiccator is required.8. Sampling, Test Speci
41、mens, and Test Units8.1 Sampling is defined as all the steps required to obtain analiquot of the contents of any pipe, tank, or other system, andto place the sample into the laboratory test container. Thelaboratory test container and sample volume shall be ofsufficient capacity to mix the sample and
42、 obtain a homoge-neous sample for analysis.8.2 ParticlesFor samples that are likely to contain par-ticles (for example, used oils or crude oils) pass the samplethrough a 75-m screen to remove the particles. For theremoval of iron filings the use of a magnet is appropriate. Waxysamples must be heated
43、 to dissolve the wax crystals prior tofiltration and a preheated filter shall be used.8.3 Test SpecimenAportion or volume of sample obtainedfrom the laboratory sample and delivered to the measuringcells. The test specimen is obtained as follows:8.3.1 Mix the sample, if required, to homogenize. Mixin
44、g atroom temperature in an open container can result in the loss ofvolatile material; mixing in closed, pressurized containers, or atsub-ambient temperatures is recommended.8.3.2 Draw the test specimen from a properly mixed labo-ratory sample using an appropriate syringe.Alternatively, if theproper
45、attachments and connecting tubes are used, the testspecimen may be delivered directly to the measuring cellsusing a flow through or pressure adapter (see 6.3) or autosam-pler (see 6.4) from the mixing container. For waxy or othersamples with a high pour point, before drawing the testspecimen, heat t
46、he laboratory sample to the desired testtemperature, which has to be high enough to dissolve the waxcrystals.9. Calibration and Verification9.1 Use only a calibrated apparatus as described in 6.1. Thecalibration shall be checked periodically using certified refer-ence standards as described in 9.2 a
47、nd 9.3. The recommendedinterval for viscosity and density calibration is once a month,for temperature control once a year. For the calibrationprocedure follow the instructions of the manufacturer of theapparatus.9.2 Certified Viscosity and Density Reference StandardsThese are for use as confirmatory
48、 checks on the procedure inthe laboratory. Certified viscosity and density reference stan-dards shall be certified by a laboratory, which has shown tomeet the requirements of ISO/IEC 17025 or a correspondingnational standard by independent assessment. Viscosity stan-dards shall be traceable to maste
49、r viscometer proceduresdescribed in Test Method D2162. Density standards shall havea certified uncertainty of the density values of 0.0001 g/cm3.The uncertainty of the reference standards shall be stated foreach certified value (k = 2; 95 % confidence level). SeeISO 5725 or NIST Technical Note 1297.9.3 ThermometerFor calibration and adjustment of thetemperature control, a digital thermometer with a probe diam-eter of 6.25 mm and a maximal length of 80 mm shall be used.For smaller probes the use of an adapter is suitable. Theuncertainty (k = 2; 95 % conf
