1、Designation: D7042 12aD7042 14Standard 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
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*1.1 This test method covers and specifies a procedure for the concurre
3、nt measurement of both the dynamic viscosity, , and thedensity, , of liquid petroleum products and crude oils, both transparent and opaque. The kinematic viscosity, , can be obtainedby dividing the dynamic viscosity, , by the density, , obtained at the same test temperature.1.2 The result obtained f
4、rom this test method is dependent upon the behavior of the sample and is intended for application toliquids for which primarily the shear stress and shear rate are proportional (Newtonian flow behavior).1.3 The precision has only been determined for those materials, viscosity ranges, density ranges,
5、 and temperatures as indicatedin Section 15 on Precision and Bias. The test method can be applied to a wider range of materials, viscosity, density, andtemperature. For materials not listed in Section 15 on Precision and Bias, the precision and bias may not be applicable.1.4 The values stated in SI
6、units are to be regarded as standard. No other units of measurement are included in this standard.1.5 This standard does not purport to address all 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
7、 practices and to determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D445 Test Method for Kinematic Viscosity of Transparent and Opaque Liquids (and Calculation of Dynamic Viscosity)D975 Specification for Diesel Fuel OilsD2162 Practice for Ba
8、sic Calibration of Master Viscometers and Viscosity Oil StandardsD2270 Practice for Calculating Viscosity Index from Kinematic Viscosity at 40 and 100CD4052 Test Method for Density, Relative Density, and API Gravity of Liquids by Digital Density MeterD6299 Practice for Applying Statistical Quality A
9、ssurance and Control Charting Techniques to Evaluate Analytical Measure-ment System PerformanceD6300 Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products and LubricantsD6617 Practice for Laboratory Bias Detection Using Single Test Result from Standard
10、MaterialD6708 Practice for Statistical Assessment and Improvement of Expected Agreement Between Two Test Methods that Purportto Measure the Same Property of a MaterialD6751 Specification for Biodiesel Fuel Blend Stock (B100) for Middle Distillate FuelsD7467 Specification for Diesel Fuel Oil, Biodies
11、el Blend (B6 to B20)2.2 ISO Standards:3ISO 5725 Accuracy (trueness and precision) of measurement methods and resultsISO/IEC 17025 General Requirements for the Competence of Testing and Calibration Laboratories2.3 Other Documents:4NIST Technical Note 1297 Guideline for Evaluating and Expressing the U
12、ncertainty of NIST Measurement Results1 This test method is under the jurisdiction ofASTM Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of SubcommitteeD02.07 on Flow Properties.Current edition approved Nov. 1, 2012May 1, 2014. Published March 2013
13、July 2014. Originally approved in 2004. Last previous edition approved in 2012 asD7042D7042 12a.121. DOI:10.1520/D7042-12A. DOI:10.1520/D7042-14.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsv
14、olume information, refer to the standards Document Summary page on the ASTM website.3 Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http:/www.ansi.org.4 Available from National Institute of Standards and Technology (NIST), 100 Bureau Dr.,
15、 Stop 1070, Gaithersburg, MD 20899-1070, http:/www.nist.gov.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 to adequately depict all chan
16、ges 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 ASTM International, 100 Bar
17、r Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13. Terminology3.1 Definitions:3.1.1 density (), nmass per unit volume.3.1.2 dynamic viscosity (), nthe ratio between the applied shear stress and rate of shear of a liquid.3.1.2.1 DiscussionIt is sometimes called the coeffi
18、cient of dynamic viscosity or, simply, viscosity. Thus, dynamic viscosity is a measure of theresistance to flow or to deformation of a liquid under external shear forces.3.1.2.2 DiscussionThe term dynamic viscosity can also be used in a different context to denote a frequency-dependent quantity in w
19、hich shear stressand shear rate have a sinusoidal time dependence.3.1.3 kinematic viscosity (), nthe ratio of the dynamic viscosity () to the density () of a liquid.3.1.3.1 DiscussionFor gravity flow under a given hydrostatic head, the pressure head of a liquid is proportional to its density (). The
20、refore thekinematic viscosity () is a measure of the resistance to 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 temperature to thedensity of a reference material (usually water) at a stated temperature.4
21、. Summary of Test Method4.1 The test specimen is introduced into the measuring cells, which are at a closely controlled and known temperature. Themeasuring cells consist of a pair of rotating concentric cylinders and an oscillating U-tube. The dynamic viscosity is determinedfrom the equilibrium rota
22、tional speed of the inner cylinder under the influence of the shear stress of the test specimen and an eddycurrent brake in conjunction with adjustment data. The density is determined by the oscillation frequency of the U-tube inconjunction with adjustment data. The kinematic viscosity is calculated
23、 by dividing the dynamic viscosity by the density.5. Significance and Use5.1 Many petroleum products, and some non-petroleum materials, are used as lubricants and the correct operation of theequipment depends upon the appropriate viscosity of the liquid being used. In addition, the viscosity of many
24、 petroleum fuels isimportant for the estimation of optimum storage, handling, and operational conditions. Thus, the accurate determination ofviscosity is essential to many product specifications.5.2 Density is a fundamental physical property that can be used in conjunction with other properties to c
25、haracterize both thelight and heavy fractions of petroleum and petroleum products.5.3 Determination of the density or relative density of petroleum and its products is necessary for the conversion of measuredvolumes to volumes at the standard temperature of 15C.6. Apparatus6.1 Stabinger Viscometer5,
26、66.1.1 Viscosity MeasurementThe Stabinger viscometer uses a rotational coaxial cylinder measuring system.The outer cylinder(tube) is driven by a motor at a constant and known rotational speed. The low-density inner cylinder (rotor) is held in the axis ofrotation by the centrifugal forces of the high
27、er density sample and in its longitudinal position by the magnet and the soft iron ring.Consequently, the system works free of bearing friction as found in rotational viscometers. A permanent magnet in the innercylinder induces eddy currents in the surrounding copper casing. The rotational speed of
28、the inner cylinder establishes itself as theresult of the equilibrium between the driving torque of the viscous forces and the retarding eddy current torque. This rotationalspeed is measured by an electronic system (Hall effect sensor) by counting the frequency of the rotating magnetic field (see Fi
29、g.1 and Fig. 2, No. 2).5 The Stabinger viscometer is covered by a patent. Interested parties are invited to submit information regarding the identification of an alternative to this patented itemto the ASTM International headquarters. Your comments will receive careful consideration at a meeting of
30、the responsible technical committee, which you may attend.6 The sole source of supply of the apparatus known to the committee at this time is Anton Paar GmbH, Anton-Paar-Str. 20, A-8054 Graz, Austria. If you are aware ofalternative suppliers, please provide this information to ASTM International hea
31、dquarters. Your comments will receive careful consideration at a meeting of the responsibletechnical committee, which you may attend.D7042 1426.1.2 Density MeasurementThe digital density analyzer uses a U-shaped oscillating sample tube and a system for electronicexcitation and frequency counting (se
32、e Fig. 2, No. 3).6.1.3 Temperature ControlThe copper block surrounds both the viscosity and the density measuring cell in a way that bothcells are held at the same temperature. A thermoelectric heating and cooling system (see Fig. 2, No. 1) ensures the temperaturestability of the copper block within
33、 60.005C60.005 C from the set temperature at the position of the viscosity cell over thewhole temperature range. The uncertainty (k = 2; 95 % confidence level) of the temperature calibration shall be no more than60.03C60.03 C over the range from 1515 C to 100C.100 C. Outside this range the calibrati
34、on uncertainty shall be no morethan 60.05C.60.05 C.6.1.4 The thermal equilibration time depends on the heat capacity and conductivity of the liquid and on the difference betweeninjection temperature and test temperature. Adequate temperature equilibration of the test specimen is automatically determ
35、inedwhen successive viscosity values are constant within 60.07 % over 1 min and successive density values are constant within60.00003 g/cm3 over 60 s.NOTE 1The Stabinger Viscometer, manufactured by Anton Paar GmbH, fulfills the stated requirements when operated in the most precise mode ofoperation.6
36、.2 Syringes, commercially available, at least 5 mL in volume, with a Luer tip. All construction materials for syringes shall befully compatible with all sample liquids and cleaning agents, which contact them.6.3 Flow-Through or Pressure Adapter, for use as an alternative means of introducing the tes
37、t specimen into the measuring cellseither by pressure or by suction, provided that sufficient care and control is used to avoid any bubble formation in the test specimen.All construction materials for adaptors shall be fully compatible with all sample liquids and cleaning agents, which contact them.
38、6.4 Autosampler, for use in automated injection analyses. The autosampler shall be designed to ensure the integrity of the testspecimen prior to and during the analysis and be equipped to transfer a representative portion of test specimen into the measuringcells. The autosampler shall transfer the t
39、est specimen from the sample vial to the measuring cells of the apparatus withoutinterfering with the integrity of the test specimen. The autosampler shall be able to mimic the procedure for sample handling asset forth in 11.1 and 11.2. The autosampler may have heating capability as a means to lower
40、 the viscosity of the sample for fillingthe measuring cells.FIG. 1 Viscosity CellFIG. 2 Cell BlockD7042 1436.5 Screen, with an aperture of 75 m, to remove particles from the sample.6.6 Magnet, strong enough to remove iron fillings from the sample. Magnetic stirring rods are suitable.6.7 Ultrasonic B
41、ath, Unheated (optional), with an operating frequency between 25 kHz to 60 kHz and a typical power outputof 100 W, of suitable dimensions to hold container(s) placed inside of bath, for use in effectively dissipating and removing airor gas bubbles that can be entrained in viscous sample types prior
42、to analysis. It is permissible to use ultrasonic baths with operatingfrequencies and power outputs outside this range, however it is the responsibility of the laboratory to conduct a data comparisonstudy to confirm that results determined with and without the use of such ultrasonic baths does not ma
43、terially impact results.7. Reagents and Materials7.1 Sample Solvent, completely miscible with the sample.7.1.1 For most samples, a volatile petroleum spirit or naphtha is suitable. If the solvent dries up without residues in an applicabletime frame, the use of a separate drying solvent is not requir
44、ed.7.1.2 For residual fuels, a prewash with an aromatic solvent such as toluene or xylene may be necessary to remove asphalticmaterial.7.2 Drying Solvent, a volatile solvent miscible with the sample solvent (see 7.1).7.2.1 Highly concentrated ethanol (96 % or higher) is suitable.7.3 Dry Air or Nitro
45、gen, for blowing the measuring cells.7.3.1 If the measuring cell temperature is below or near the dew point temperature of the ambient air, the use of an appropriatedesiccator is required.8. Sampling, Test Specimens, and Test Units8.1 Sampling is defined as all the steps required to obtain an aliquo
46、t of the contents of any pipe, tank, or other system, and toplace the sample into the laboratory test container. The laboratory test container and sample volume shall be of sufficient capacityto mix the sample and obtain a homogeneous sample for analysis.8.1.1 For some sample types, such as viscous
47、lube oils that are prone to having entrained air or gas bubbles present in thesample, the use of an ultrasonic bath (see 6.7) without the heater turned on (if so equipped), has been found effective in dissipatingbubbles typically within 1 min.8.2 ParticlesFor samples that are likely to contain parti
48、cles (for example, used oils or crude oils) pass the sample through a75-m75 m screen to remove the particles. For the removal of iron filings the use of a magnet is appropriate. Waxy samples mustbe heated to dissolve the wax crystals prior to filtration and a preheated filter shall be used.8.3 Test
49、SpecimenA portion or volume of sample obtained from the laboratory sample and delivered to the measuring cells.The test specimen is obtained as follows:8.3.1 Mix the sample, if required, to homogenize. Mixing at room temperature in an open container can result in the loss ofvolatile material; mixing in closed, pressurized containers, or at sub-ambient temperatures is recommended.8.3.2 Draw the test specimen from a properly mixed laboratory sample using an appropriate syringe.Alternatively, if the properattachments and connecting tubes
