1、Designation: E2975 14Standard Test Method forCalibration of Concentric Cylinder Rotational Viscometers1This standard is issued under the fixed designation E2975; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revi
2、sion. 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 describes the calibration (or perfor-mance validation) of rotational viscometers in which therotational elemen
3、t is immersed in the test fluid under ambienttemperature conditions. It is not intended for cone-and-plate orparallel plate viscometers.1.2 Calibration shall be performed using experimentalconditions, such as temperature, viscosity range and shear rate(rotational speed), as close as practical to tho
4、se to be used formeasurement of test specimens.1.3 The values stated in SI units are to be regarded asstandard. The values given in parentheses are mathematicalconversions to inch-pound units that are provided for informa-tion only and are not considered standard.1.3.1 Common viscosity units of Pois
5、e (P) are related to theSI units by the equivalency 1 cP = 1 mPas.1.4 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 establish appro-priate safety and health practices and determine the app
6、lica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E473 Terminology Relating to Thermal Analysis and Rhe-ologyE1142 Terminology Relating to Thermophysical PropertiesE1970 Practice for Statistical Treatment of ThermoanalyticalData3. Terminology3.1 Definition
7、sSpecific technical terms used in this testmethod are described in Terminologies E473 and E1142including Newtonian, non-Newtonian, stress, strain,viscometer, viscometry, and viscosity.3.2 Definitions of Terms Specific to This Standard:3.2.1 apparent viscosity (), nviscosity determined by thistest me
8、thod.3.2.1.1 DiscussionBecause the velocity gradient in thistest method may not be the same at all points of the rotationalelement for non-Newtonian fluids, the result determined maynot be the true viscosity. Therefore, the viscosity determined bythis test method is called the “apparent viscosity.”4
9、. Summary of Test Method4.1 An element is rotated in a Newtonian fluid at a known(or measured) speed. The viscous drag experienced by theimmersed element is measured (or known) as a torque.Viscosity may then be determined from these properties(torque and rotational speed) and the dimensions of thero
10、tational element by equations such as Eq 1 and 2. 5 E S 5 9.55 E S (1)S 5 rc22 rg2! 4 rc2rg2L!# (2)where: = viscosity (Pas), = rotational speed (revolutions/min),E = calibration coefficient (dimensionless), = torque (Nm),S = rotational element factor (mm-3) supplied by the appa-ratus vendor,L = leng
11、th of the cylindrically shaped rotational element(mm),rg= radius of the cylindrically shaped rotational element(mm),rc= radius of the cylindrically shaped container (mm), and = rotational speed (rad/s).NOTE 11 Pa = 1 N/m2; 1 cP = 1 mPas; 1 rev/min = 0.1047 rad/s.4.2 Calibration of a viscometer and i
12、ts associated rotationalelement may be achieved by comparing the viscosity indicatedby the apparatus with the known viscosity of a calibration fluidas their product using Eq 3, under experimental conditionsused in measuring an unknown fluid:E 5 t o(3)1This test method is under the jurisdiction ofAST
13、M Committee E37 on ThermalMeasurements and is the direct responsibility of Subcommittee E37.08 on Rheol-ogy.Current edition approved Aug. 1, 2014. Published August 2014. DOI: 10.1520/E2975-14.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at ser
14、viceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1where:t= the viscosity of the calibration fluid (Pas),
15、andt= the viscosity indicated by the apparatus (Pas).5. Significance and Use5.1 This test method may be used to calibrate a rotationalviscometer and its associated rotational element.5.2 The apparent viscosity () of a test specimen may thenbe obtained using Eq 4: 5 E o(4)6. Apparatus6.1 Viscometer,
16、Concentric Cylinder RotationalThe es-sential instrumentation required providing the minimum rota-tional viscometer analytical capabilities for this test methodinclude:6.1.1 A drive motor, to apply a rotational displacement tothe specimen at a rate from 3 to 380 rad/min (0.5 to 60revolutions/min) con
17、stant to 60.2 % of full scale or alterna-tively a torque to the specimen constant to 60.2 % of full scale.6.1.2 A coupling shaft, or other means to transmit therotational displacement from the motor to the specimen.NOTE 2It is convenient to have a mark on the shaft to indicate thefluid level of the
18、test specimen appropriate for the measurement.6.1.3 A cylindrical rotational element, spindle, bob, or tool,composed of material inert to the material being tested, to fixthe specimen between the drive shaft and a stationary position.NOTE 3Each rotational element typically covers about two decades o
19、fviscosity. The rotational element is selected so that the measured viscosityis between 15 and 95 % of the range that element.NOTE 4This test method is intended for rotational elements that areimmersed in the test specimen. It is not intended for cone-and-plate orparallel plate viscometers.6.1.4 A s
20、ensor to measure the torque within 61 % of fullscale developed by the specimen or alternatively to measurerotational speed within 61 % of full scale.6.1.5 A temperature sensor to provide an indication of thespecimen temperature of the range of 19C to 26C to within60.1C.6.1.6 A temperature bath to pr
21、ovide a controlled isothermaltemperature environment for the specimen within the appli-cable temperature range of this test method.6.1.7 A temperature controller, capable of maintaining thebath at a temperature constant to 60.1C over the range of19C to 26C.6.1.8 A data collection device, to provide
22、a means ofacquiring, storing, and displaying measured or calculatedsignals, or both. The minimum output signals required forrotational viscosity are torque, rotational speed, temperature,and time.6.1.9 A stand, to support, level, lower and raise the drivemotor, shaft and rotational element.6.1.10 A
23、specimen container, cylindrical in shape suitablefor the rotational element (6.1.3), to contain the test specimenduring testing.NOTE 5The specific container may depend upon the rotationalelement being used (see vendors recommendation). In the absence of otherinformation, a low form Griffin beaker of
24、 600 mL capacity shall be used.6.1.11 Auxiliary instrumentation considered necessary oruseful in conducting this test method includes:6.1.11.1 Data analysis capability to provide viscosity, stressor other useful quantities derived from measured signals.6.1.11.2 A level to indicate the vertical plumb
25、 of the drivemotor, shaft and rotational element.NOTE 6Viscometers and their rotational elements are precisionequipment and shall be kept from undue shock and mishandling. Physicaldamage to the instrument may reveal itself as erratic torque indicationwhen the instrument, with or without a rotational
26、 element in place, isoperated in air. When operating normally, the indicated signal will bestable and have a value of zero when operated in air.NOTE 7Care shall be taken in the storage and handling of rotationalelements and assemblies. Protect them from dust, corrosive deposits, andmechanical abuse.
27、 Avoid touching the calibrated section of the rotationalelements with the hands. Clean the element and sample containerthoroughly after each use.7. Reagents and Materials7.1 One or more viscosity reference fluid (with its accom-panying certification) in the range of that anticipated for thetest spec
28、imen measurement.NOTE 8Viscosity reference materials are typically available from theviscometer supplier.8. Preparation of Apparatus8.1 Perform any viscometer preparation or calibration pro-cedures described by the manufacturer in the operationsmanual.8.2 Operate the viscometer in air with a connect
29、ed rotationalelement in place. The indicator shall be stable and indicate azero value.8.3 Set the temperature bath to 23C and equilibrate for 30minutes. Measure the temperature bath and ensure that itstemperature is 23 6 0.2C.NOTE 9Other temperatures may be used but shall be reported.9. Procedure9.1
30、 Selection of the Rotational Element:9.1.1 From the estimated viscosity of the test specimen,select a rotational element that will produce readings in thedesired range.NOTE 10Where more than one rotational element is available for therange selected, choose an element that produces results nearest th
31、emidpoint of the measurable viscosity range. Viscometer scale reading shallbe within the range of 15 to 95 % of full scale.9.2 Preparation of the Viscosity Reference Material:9.2.1 Place the required amount of the reference materialmeasured to the nearest 0.5 mL in the sample container.NOTE 11Pour t
32、he reference material slowly down the side of thesample container taking care to prevent incorporation of air into thematerial.NOTE 12The amount of viscosity reference material varies with eachrotational element and container combination. See the manufacturersinstruction manual for the correct amoun
33、t of liquid for each element/container pair.E2975 1429.2.2 Place the container with its reference material in thetemperature bath at 23.0 6 0.2C and equilibrate for 30minutes (see Note 9).9.3 Assemble the Apparatus:9.3.1 Vertically aligned and level the viscometer on itssupporting stand.9.3.2 Connec
34、t the rotational element selected in 9.1.1 to thecoupling link.9.3.3 Align the rotational element (and apparatus) over thesample container.9.4 Rotational Element Insertion:9.4.1 Slowly lower the rotational element into the referencematerial container until the fluid covers the element reaches alevel
35、 approximately 3 mm above the active area of the element.NOTE 13The shaft may have a mark to indicate the appropriate fluidlevel for measurement.NOTE 14Take care not to trap any air bubbles under the geometry.9.4.2 Initiate the rotation of the rotational element at thelowest speed available for 30 m
36、inutes.9.4.3 Measure the temperature of the test specimen (T).NOTE 15If the temperature is not 23.0 6 0.2C, allow the testspecimen to equilibrate for an addition 30 min or until the desiredtemperature range and stability is observed.9.5 Viscosity Determination:9.5.1 Turn on the motor and rotate the
37、element at its lowestspeed.9.5.2 Increase the rotational speed (or torque) to that re-quired to produce a reading nearest the midpoint of the scale.9.5.3 Stop the rotation of the element and wait for 1 min.9.5.4 Restart the rotation of the element at the same rota-tional speed (or torque) and allow
38、at least 5 revolutions of theelement.9.5.5 Measure the observed viscosity (o(1) (or torque (1)and rotational speed (1).9.5.6 Repeat steps 9.5.3 9.5.5 two more times measuringthe indicated viscosity as o(2) and o(3), respectively.9.5.7 Calculate the mean value and standard deviation for , and ofrom s
39、teps 9.5.3 9.5.6 (see Practice E1970).9.5.8 Calculate the Calibration Constant and its standarddeviation using Eq 3 and 4.9.6 Shut Down:9.6.1 Remove the rotational element from the test fluid byelevating the measurement apparatus on its stand.9.6.2 Disassemble and clean the rotational element.NOTE 1
40、6The rotational element and sample container may be cleanedwith a solvent compatible with the test fluid and the element. Water,xylene, ethanol, or higher alcohols are commonly used.NOTE 17Care shall be taken to avoid scratching or deforming therotational element.9.6.3 Safely store or dispose of the
41、 reference material.10. Calculation or Interpretation of Results10.1 Calculate the experimental calibration coefficient (E)and its standard deviation (E) deviation (at the indicatedtemperature) using Eq 3 and 4.E 5 t t!21 o o!2#12E (5)where:E = calibration coefficient (dimensionless),o= observed vis
42、cosity (Pas),t= reference material viscosity from certificate (Pas),E = estimated standard deviation in calibration coefficient(dimensionless),o= standard deviation of observed viscosity measurement(Pas), andt= standard deviation of reference viscosity (obtainedfrom the reference material certificat
43、e) (Pas).10.2 The shear rate (d/dt) may be determined from:ddt5 2 rc2 rc22 rg2!# 60 s/min#5 4 rc rc22 rg2! (6)where:d/dt = shear rate (s-1). = rotation speed (revolutions/min). = rotational speed (rad/s),rc= inside radius of container (mm), andrg= radius of rotational element (mm).11. Report11.1 The
44、 report shall include the following:11.1.1 A complete description of the rotational viscometer,its mode of operation (that is, constant rotational velocity orconstant torque), and its rotational element;11.1.2 A complete description of the calibration fluid in-cluding its supplier, model number, and
45、 serial number (or dateof manufacture);11.1.3 A statement of viscosity and measurement conditionsincluding temperature and shear rate (or rotational speed androtational element);11.1.4 Calibration coefficient and its standard deviation; and11.1.5 The dated version of this test method used.11.1.6 For
46、 Example: Calibration Constant E = (value) 6(value) at 23C with (supplier) 25 mm bob, 8.3 mNm of torqueat shear rate of 10/s or (supplier) spindle 31, 48 % torque at 60rev/min.12. Precision and Bias12.1 An interlaboratory test is planned for 20152020 toestablish within laboratory repeatability, betw
47、een laboratoryreproducibility, and bias. Anyone wishing to participate in thisinterlaboratory study should contact the Committee E37 StaffManager at ASTM International Headquarters.12.2 Precision:12.2.1 A limited repeatability study was performed in 2013using a single calibration fluid in a single l
48、aboratory. Therepeatability standard deviation for this intralaboratory studywas 0.9 %.12.2.2 Within laboratory variability may be described usingthe repeatability value (r) obtained by multiplying the relativestandard deviation by 2.8. The repeatability value estimates the95 % confidence limit. Tha
49、t is, two results obtained in the samelaboratory, using the same apparatus, on the same specimen,closely spaced in time have a 95 % probability of being withinthe repeatability value of each other.12.3 Bias:E2975 14312.3.1 Bias is the difference between a mean determinedvalue and an accepted reference value.12.3.2 This test method is used to determine the bias in acalibration result.12.3.3 In a perfect system, the calibration coefficient valueshould be
