1、Designation: D446 12Designation: 71/2/95Standard Specifications and Operating Instructions forGlass Capillary Kinematic Viscometers1This standard is issued under the fixed designation D446; the number immediately following the designation indicates the year oforiginal adoption or, in the case of rev
2、ision, 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.This standard has been approved for use by agencies of the Department of Defense.1. Scope*1.1 These specificati
3、ons cover operating instructions forglass capillary kinematic viscometers of all the types describedin detail in Annex A1, Annex A2, and Annex A3 as follows:Modified Ostwald viscometers, Annex A1Suspended-level viscometers, Annex A2Reverse-flow viscometers, Annex A31.2 The calibration of the viscome
4、ters is described inSection 6.1.3 This standard covers some widely used viscometerssuitable for use in accordance with Test Method D445. Otherviscometers of the glass capillary type which are capable ofmeasuring kinematic viscosity within the limits of precisiongiven in Test Method D445 may be used.
5、1.4 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.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 B
6、asic Calibration of Master Viscometersand Viscosity Oil Standards2.2 ISO Documents:3ISO 3104 Petroleum ProductsTransparent and OpaqueLiquidsDetermination of Kinematic Viscosity and Cal-culation of Dynamic ViscosityISO 3105 Glass Capillary Kinematic ViscometersSpecifications and Operating Instruction
7、sISO 5725 Basic Methods for the Determination of Repeat-ability and Reproducibility of a Standard MeasurementMethodISO 17025 General Requirements for the Competence ofTesting and Calibration LaboratoriesISO Guide 25 General Requirements for the Calibration andTesting Laboratories2.3 NIST Standards:4
8、NIST 1297 Guidelines for Evaluating and Expressing theUncertainty of NIST Measurement Results3. Materials and Manufacture3.1 Fully annealed, low-expansion borosilicate glass shallbe used for the construction of all viscometers. The sizenumber, serial number, and manufacturers designation shall beper
9、manently marked on each viscometer. All timing marksshall be etched and filled with an opaque color, or otherwisemade a permanent part of the viscometer. See detailed descrip-tion of each type of viscometer in Annex A1, Annex A2, andAnnex A3.3.2 With the exception of the FitzSimons and Atlanticvisco
10、meters, all viscometers are designed to fit through a51-mm hole in the lid of a constant-temperature bath having aliquid depth of at least 280 mm; and it is assumed that thesurface of the liquid will be not more than 45 mm from the topof the bath lid. For certain constant-temperature baths, espe-cia
11、lly at low or high temperatures, it may be necessary toconstruct the viscometers with the uppermost tubes longer thanshown to ensure adequate immersion in the constant-temperature bath. Viscometers so modified can be used tomeasure kinematic viscosity within the precision of the testmethod.The lengt
12、hs of tubes and bulbs on the figures should beheld within 610 % or 610 mm, whichever is less, such thatthe calibration constant of the viscometer does not vary bymore than 615 % from the nominal value.1These specifications and operating instructions are under the jurisdiction ofASTM Committee D02 on
13、 Petroleum Products and Lubricants and are the directresponsibility of Subcommittee D02.07 on Flow Properties.Current edition approved Dec. 1, 2012. Published March 2013. Originallyapproved in 1966 as D2515 66. Redesignated D446 in 1977. Last previous editionapproved in 2007 as D446 07. DOI: 10.1520
14、/D0446-12.2For 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.3Available from American National Standards Institu
15、te (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036.4Available from National Institute of Standards and Technology (NIST), 100Bureau Dr., Stop 1070, Gaithersburg, MD 20899-1070, http:/www.nist.gov.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100
16、Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14. Nomenclature for Figures4.1 The figures in the annexes contain letters to designatespecific parts of each viscometer. These letters are also used inthe text of the standard when reference to the viscometers isgiven. T
17、he more frequently used letters on the figures in theannexes are as follows:A lower reservoirB suspended levelbulbC and J timing bulbsD upper reservoirE, F, and I timing marksG and H filling marksK overflow tubeL mounting tubeM lower vent tubeN upper vent tubeP connecting tubeR working capillary5. V
18、iscometer Holder and Alignment5.1 All viscometers which have the upper meniscus directlyabove the lower meniscus (Cannon-Fenske routine in AnnexA1 and all in Annex A2) shall be mounted in a constanttemperature bath with tube L held within 1 of the vertical asobserved with a plumb bob or other equall
19、y accurate inspectionmeans. A number of commercially available holders are sodesigned that the tube L is held perpendicular to the lid of aconstant-temperature bath; nevertheless, the viscometer shouldbe tested with a plumb line in order to ensure that the tube Lis in a vertical position.5.1.1 Those
20、 viscometers whose upper meniscus is offsetfrom directly above the lower meniscus (all others in AnnexA1and all in Annex A3) shall be mounted in a constant-temperature bath with tube L held within 0.3 of the vertical.5.2 Round metal tops, designed to fit above a 51-mm hole inthe lid of the bath, are
21、 frequently cemented on to the Zeitfuchs,Zeitfuchs cross-arm, and Lantz-Zeitfuchs viscometers whichthen are permanently mounted on the lid of the bath. Also arectangular metal top, 25 mm 59 mm, is often cemented onto the Zeitfuchs cross-arm and Zeitfuchs viscometers. Viscom-eters fitted with metal t
22、ops should also be set vertically in theconstant-temperature bath with the aid of a plumb line.5.3 In each figure, the numbers which follow the tubedesignation indicate the outside tube diameter in millimetres. Itis important to maintain these diameters and the designatedspacing to ensure that holde
23、rs will be interchangeable.6. Calibration of Viscometers6.1 Procedures:6.1.1 Calibrate the kinematic glass capillary viscometerscovered by this standard using the procedures described inAnnex A1, Annex A2, and Annex A3.6.2 Reference Viscometers:6.2.1 Select a clear petroleum oil, free from solid par
24、ticlesand possessing Newtonian flow characteristics, with a kine-matic viscosity within the range of both the reference viscom-eter and the viscometer to be calibrated. The minimum flowtime shall be greater than that specified in the appropriate tableof the annex in both the reference viscometer and
25、 the viscom-eter which is to be calibrated in order that the kinetic energycorrection (see 7.1 and 7.2) may be less than 0.2 %.6.2.2 Select a calibrated viscometer of known viscometerconstant C1. This viscometer may be a reference viscometer(driving head at least 400 mm) that has been calibrated by
26、thestep-up procedure using viscometers of successively largercapillary diameters, starting with distilled water as the basickinematic viscosity standard or a routine viscometer of thesame type that has been calibrated by comparison with areference viscometer. See Test Method D2162.6.2.3 Mount the ca
27、librated viscometer together with theviscometer to be calibrated in the same bath and determine theflow times of the oil in accordance with Test Method D445.6.2.3.1 The calibration of the reference viscometer shouldonly be carried out by a reputable laboratory meeting therequirements of, for example
28、, ISO Guide 25.6.2.4 Calculate the viscometer constant C1as follows:C15 t23C2!/t1(1)where:C1= the constant of the viscometer being calibrated,t1= the flow time to the nearest 0.1 s in the viscometerbeing calibrated,C2= the constant of the calibrated viscometer, andt2= the flow time to the nearest 0.
29、1 s in the calibratedviscometer.6.2.5 Repeat 6.2.1-6.2.3 with a second oil whose flow timesare at least 50 % longer than the first oil. If the two values ofC1differ by less than 0.2 % for those viscometers listed inAnnex A1 and Annex A2 and less than 0.3 % for thoseviscometers listed in Annex A3, us
30、e the average. If theconstants differ by more than this value, repeat the proceduretaking care to examine all possible sources of errors.6.2.5.1 The calibration constant, C, is dependent upon thegravitational acceleration at the place of calibration and thismust, therefore, be supplied by the standa
31、rdization laboratorytogether with the instrument constant. Where the accelerationof gravity, g, differs by more than 0.1 %, correct the calibrationconstant as follows:C25g2/g1!3C1(2)where subscripts 1 and 2 indicate respectively the standard-ization laboratory and the testing laboratory.6.3 Certifie
32、d Viscosity Reference Standards:6.3.1 Certified viscosity reference standards shall be certi-fied by a laboratory that has been shown to meet the require-ments of ISO 17025 by independent assessment. Certifiedviscosity reference standards shall be traceable to masterviscometer procedures described i
33、n Practice D2162.6.3.1.1 The uncertainty of the certified viscosity referencestandard shall be stated for each certified value (k=2, 95%confidence). See ISO 5725 or NIST 1297.6.3.2 Select from Table 1 a certified viscosity referencestandard with a kinematic viscosity at the calibration tempera-ture
34、within the kinematic viscosity range of the viscometer tobe calibrated and a minimum flow time greater than thatspecified in the appropriate table of the annex. Determine theD446 122flow time to the nearest 0.1 s in accordance with Test MethodD445 and calculate the viscometer constant, C, as follows
35、:C 5 /t (3)where: = the kinematic viscosity, mm2/s, for the certified viscos-ity reference standard, andt = the flow time, s.6.3.3 Repeat with a second certified viscosity referencestandard whose flow times are at least 50 % longer than thefirst certified viscosity reference standard. If the two val
36、ues ofC differ by less than 0.2 % for those viscometers listed inAnnex A1 and Annex A2 and less than 0.3 % for thoseviscometers listed in Annex A3, use the average as theviscometer constant for the viscometer being calibrated. If theconstants differ by more than this value, repeat the proceduretakin
37、g care to examine all possible sources of errors.6.4 Expression of Constant:6.4.1 Report the constant to the nearest 0.1 % of thedetermined value. This generally means four significant figuresfrom 1 10Nto 6.999 10Nand three significant figures from710Nto 9.99 10N.7. Kinematic Viscosity Calculation7.
38、1 Basic Formula:7.1.1 Kinematic viscosity, expressed in mm2/s, can becalculated from the viscometer dimensions as follows: 5 106gD4Ht/128 VL! 2 E/t2(4)where: = the kinematic viscosity, mm2/s,g = the acceleration due to gravity, m/s2,D = the diameter of the capillary, m,L = the length of the capillar
39、y, m,H = the average distance between the upper and lowermenisci, m,V = the timed volume of liquids passing through thecapillary, m3(approximately the volume of the timingbulb),E = the kinetic energy factor, mm2s, andt = the flow time, s.7.1.2 If the viscometer is selected so that the minimum flowti
40、me shown in the tables of Annex A1, Annex A2, and AnnexA3 are exceeded, the kinetic energy term, E/t2, becomesinsignificant and Eq 4 may be simplified by grouping thenon-variable terms into a constant, C, as follows: 5 Ct (5)7.2 Kinetic Energy Correction:7.2.1 The viscometers described in the Annex
41、A1, AnnexA2, and Annex A3 are designed such that the kinetic energycorrection term, E/t2, is negligible if the flow time is more than200 s. In the case of several sizes of viscometers for themeasurement of low-kinematic viscosity liquids, a minimumflow time greater than 200 s is required in order th
42、at the kineticenergy correction term, E/ t2, shall be negligible. The minimumflow times required are set out as footnotes to the appropriatetables of viscometer dimensions given in the AnnexA1, AnnexA2, and Annex A3.7.2.2 For viscometers whose constants are 0.05 mm2/s2orless, a kinetic energy correc
43、tion can be significant if theminimum 200 s flow is not observed. Where this is notpossible, Eq 5 takes on the following form:kinematic viscosity, mm2/s 5 Ct 2 E/t2(6)where:E = kinetic energy factor, mm2s,C = viscometer constant, mm2/s2,t = flow time, s.7.2.3 Although the kinetic energy factor, E,is
44、notaconstant, it may be approximated by means of the followingequation:E 5 52.5 V3/2/LCd!1/2(7)where:(using the units given in Figs. A1.1-A3.4)V = volume of the timing bulb, mL,L = capillary working length, mm,d = capillary working diameter, mm,C = viscometer constant, mm2/s2.NOTE 1The kinetic energ
45、y factor for certain viscometer designs andflow time use can result in significant kinematic viscosity errors. Deter-mine the effect of the kinetic energy factor for viscometers not describedin this specification.7.3 Maximum Flow Time:7.3.1 The limit of 1000 s has been set arbitrarily forconvenience
46、 as the recommended maximum flow time for theviscometers covered by this standard. Longer flow times maybe used.7.4 Surface Tension Correction :7.4.1 If the two menisci have different average diametersduring the flow time and if the surface tension of the samplediffers substantially from the calibra
47、ting liquid, a surfaceTABLE 1 Certified Viscosity Reference StandardsDesignationApproximate Kinematic Viscosity, mm2/s20C 25C 40C 50C 80C 100CS3 4.6 4.0 2.9 . . 1.2S6 11 8.9 5.7 . . 1.8S20 44 34 18 . . 3.9S60 170 120 54 . . 7.2S200 640 450 180 . . 17S600 2400 1600 520 280 67 32S2000 8700 5600 1700 .
48、 . 75S8000 37 000 23 000 6700 . . .S30000 . 81 000 23 000 11 000 . .D446 123tension correction is necessary. The changed C constant, C2,isgiven approximately as follows:C25 C1112/gh!1/ru2 1/rl!1/12 2/2!#(8)where:g = the acceleration due to gravity, m/s2,h = the average driving head, m,ru= the averag
49、e radius of the upper meniscus, m,rl= the average radius of the lower meniscus, m, = the surface tension, N/m, and = the density, in kg/m3.Subscripts 1 and 2 relate to values with the calibrating liquidand the test portion, respectively.7.4.2 While this correction applies to all viscometers, anumber of viscometers are designed to minimize the surfacetension correction. The greatest correction normally encoun-tered is with a viscometer calibrated with water and used foroils. Generally, viscometers are calibrated and used withhydrocar
