1、Designation: E2975 15Standard 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 with Newtonian refer-ence materials using experimental conditions, such astemperature, viscosity range and shear rate (rotational
4、 speed),as close as practical to those to be used for measurement of testspecimens.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.
5、1.3.1 Common viscosity units of Poise (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 he
6、alth practices and determine the applica-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 Thermoanalyt
7、icalData3. Terminology3.1 DefinitionsSpecific 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 (),
8、nviscosity determined by thistest method.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
9、is called the “apparent viscosity.”4. 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 rotationa
10、l speed) and the dimensions of therotational element by equations such as Eq 1 and 2. 5 9.55 E S (1)S 5 rc22 rg2! 4 rc2rg2L!# (2)where: = viscosity (Pas), = rotational speed (r/min),E = calibration coefficient (dimensionless), = torque (Nm),S = rotational element factor (mm-3) supplied by the appa-r
11、atus vendor,L = length of the cylindrically shaped rotational element(mm),rg= radius of the cylindrically shaped rotational element(m), andrc= radius of the cylindrically shaped container (m).NOTE 11 Pa = 1 N/m2; 1 cP = 1 mPas; 1 r/min = 0.1047 rad/s.4.2 Calibration of a viscometer and its associate
12、d 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)where:t= the viscosity of the calibration fluid (Pas), and1Th
13、is test method is under the jurisdiction ofASTM Committee E37 on ThermalMeasurements and is the direct responsibility of Subcommittee E37.08 on Rheol-ogy.Current edition approved Sept. 1, 2015. Published October 2015. Originallyapproved in 2014. Last previous edition approved in 2014 as E2975 14. DO
14、I:10.1520/E2975-15.2For 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.Copyright ASTM International, 100 Barr Har
15、bor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1o= 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
16、 may thenbe obtained using Eq 4: 5 E o(4)6. Apparatus6.1 Viscometer, 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 sp
17、ecimen at a rate from 0.5 to 60 r/min constant to 60.2 %of full scale or alternatively a torque to the specimen constantto 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 sh
18、aft to indicate thefluid level of the 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 elemen
19、t typically covers about two decades ofviscosity. 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
20、orparallel plate viscometers.6.1.4 A sensor 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 with
21、in60.1C.6.1.6 A temperature bath to provide 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
22、 A data collection device, to provide 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,
23、shaft and rotational element.6.1.10 A 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 otherinf
24、ormation, a low form Griffin beaker of 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
25、A level to indicate the vertical plumb 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 in
26、strument, with or without a rotational 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, co
27、rrosive deposits, andmechanical abuse. 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 rang
28、e of that anticipated for thetest specimen 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 Operat
29、e the viscometer in air with a connected 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
30、 but shall be reported.9. Procedure9.1 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 el
31、ement that produces results nearest themidpoint 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
32、 in the sample container.NOTE 11Pour the 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 manufacturersin
33、struction manual for the correct amount of liquid for each element/container pair.9.2.2 Place the container with its reference material in thetemperature bath at 23.0 6 0.2C and equilibrate for 30minutes (see Note 9).E2975 1529.3 Assemble the Apparatus:9.3.1 Vertically aligned and level the viscomet
34、er on itssupporting stand.9.3.2 Connect 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 f
35、luid covers the element reaches alevel 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
36、 at thelowest speed available for 30 minutes.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
37、.5.1 Turn on the motor and rotate the 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 ro
38、ta-tional speed (or torque) and allow 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 an
39、d standard deviation for , and ofrom steps 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 a
40、nd clean the rotational element.NOTE 16The 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 elemen
41、t.9.6.3 Safely store or dispose of the 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 coeff
42、icient (dimensionless),o= observed viscosity (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 (obtained
43、from the reference material certificate) (Pas).10.2 The shear rate (d/dt) may be determined from:ddt5 2 rc2! rc22 rg2!# (6)where:d/dt = shear rate (s-1), = rotational speed (rad/s),rc= inside radius of container (mm), andrg= radius of rotational element (mm).11. Report11.1 The report shall include t
44、he 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 serial number (or date
45、of 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 Example: Calibration C
46、onstant 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 60r/min.12. Precision and Bias12.1 An interlaboratory test involving 20 laboratories wasconducted in 2015 to establish the within laboratory repeat-ability o
47、f this standard.3Two specimens were examined; acalibration material and a Newtonian test specimen. Partici-pants used nine instrument models from five manufacturers.12.2 Precision:12.2.1 Within laboratory variability may be described usingthe repeatability value (r) obtained by multiplying the relat
48、ivestandard deviation by 2.8. The repeatability value estimates the95 % confidence limit. That 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.12.2.2 The
49、 relative repeatability value (r) for the determi-nation of the calibration constant was 0.67 %.12.2.3 The relative repeatability value (r) for a Newtonianfluid was 1.8 %.12.2.4 No statistically significant difference (at the 95 %confidence level) was observed in within laboratory precisionfor apparatus from differing vendors.3Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:E37-1047. ContactASTM
