1、Designation: D 446 07Designation: 71/2/95An American National StandardStandard Specifications and Operating Instructions forGlass Capillary Kinematic Viscometers1This standard is issued under the fixed designation D 446; 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 (e) indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defens
3、e.1. Scope*1.1 These specifications 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.
4、2 The calibration of the viscometers is described inSection 6.1.3 This standard covers some widely used viscometerssuitable for use in accordance with Test Method D 445. Otherviscometers of the glass capillary type which are capable ofmeasuring kinematic viscosity within the limits of precisiongiven
5、 in Test Method D 445 may be used.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:2D 445 Test Method for Kinematic Viscosity of Transparentand Opaque Liquids (and Calculation of Dyna
6、mic Viscos-ity)D 2162 Practice for Basic Calibration of Master Viscom-eters and 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 ViscometersSp
7、ecifications and Operating InstructionsISO 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 andTe
8、sting Laboratories2.3 NIST Standards:4NIST 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
9、 manufacturers designation shall bepermanently 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 excepti
10、on of the FitzSimons and Atlanticviscometers, 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 certai
11、n constant-temperature baths, espe-cially 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
12、 precision of the testmethod.The lengths 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 th
13、e jurisdiction ofASTM Committee D02 on Petroleum Products and Lubricants and are the directresponsibility of Subcommittee D02.07 on Flow Properties.Current edition approved Jan. 1, 2007. Published January 2007. Originallyapproved in 1966 as D 2515 66. Redesignated D 446 in 1977. Last previousedition
14、 approved in 2006 as D 446 06.2For 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 Nation
15、al Standards Institute (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.1*A Summary of Changes section appears at the end of this standard.Copyright AS
16、TM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4. 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
17、viscometers isgiven. The 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
18、 working capillary5. Viscometer 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 plu
19、mb bob or other equally 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 vertica
20、l position.5.1.1 Those viscometers whose upper meniscus is offsetfrom directly above the lower meniscus (all others inAnnexA1and 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
21、 lid of the bath, are 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 3 59 mm, is often cemented onto the Zeitfuchs cross-arm and Zeitfuchs viscometers. Viscom-et
22、ers fitted with metal tops 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 designatedspaci
23、ng to ensure that holders 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 o
24、il, free from solid particlesand 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 r
25、eference viscometer and 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
26、has been calibrated by 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 D
27、 2162.6.2.3 Mount the calibrated viscometer together with theviscometer to be calibrated in the same bath and determine theflow times of the oil in accordance with Test Method D 445.6.2.3.1 The calibration of the reference viscometer shouldonly be carried out by a reputable laboratory meeting thereq
28、uirements of, for example, ISO Guide 25.6.2.4 Calculate the viscometer constant C1as follows:C15 t23 C2!/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 f
29、low time to the nearest 0.1 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 thoseviscomet
30、ers listed in Annex A3, use 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,
31、 be supplied by the standardization laboratorytogether with the instrument constant. Where the accelerationof gravity, g, differs by more than 0.1 %, correct the calibrationconstant as follows:C25 g2/g1! 3 C1(2)where subscripts 1 and 2 indicate respectively the standard-ization laboratory and the te
32、sting laboratory.6.3 Certified 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 mastervisc
33、ometer procedures described in Practice D 2162.6.3.1.1 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
34、 the calibration tempera-ture 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 theflow time to the nearest 0.1 s in accordance with Test MethodD 445 and calculate the viscometer
35、constant, C, as follows:C 5n/t (3)D446072where:n = the kinematic viscosity, mm2/s, for the certified vis-cosity 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 ref
36、erence standard. If the two values 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 v
37、alue, repeat the proceduretaking 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 3 10Nto 6.999 3 10Nand three significant figuresfrom 7 3 10Nto 9.99 3
38、10N.7. Kinematic Viscosity Calculation7.1 Basic Formula:7.1.1 Kinematic viscosity, expressed in mm2/s, can becalculated from the viscometer dimensions as follows:n5106pgD4Ht/128 VL! 2 E/t2(4)where:n = the kinematic viscosity, mm2/s,g = the acceleration due to gravity, m/s2,D = the diameter of the ca
39、pillary, m,L = the length of the capillary, 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 viscomet
40、er is selected so that the minimum flowtime 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:n5Ct (5)7.2 Kinetic Energy Correction:7.2.1
41、 The viscometers described in the Annex 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 gr
42、eater than 200 s is required in order that 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 theAnnexA1,AnnexA2, and Annex A3.7.2.2 For viscometers whose constants are 0.05
43、 mm2/s2orless, a kinetic energy correction 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 E/t2(6)where:E = kinetic energy factor, mm23 s,C = viscometer constant, mm2/s2,t = flow time, s.7.2.3 Al
44、though the kinetic energy factor, E, is not a con-stant, 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 = viscomet
45、er constant, mm2/s2.NOTE 1The kinetic energy 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 100
46、0 s has been set arbitrarily forconvenience 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 sa
47、mplediffers substantially from the calibrating liquid, a surfacetension correction is necessary. The changed C constant, C2,isgiven approximately as follows:C25 C11 1 2/gh!1/ru2 1/rl!g1/r12g2/r2!# (8)TABLE 1 Certified Viscosity Reference StandardsDesignationApproximate Kinematic Viscosity, mm2/s20C
48、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 . . 75S8000 37 000 23 000 6700 . . .S30000 . 81 000 23 000 11 000 . .D446073where:g = the acceleration due to gravity, m/s2
49、,h = the average driving head, m,ru= the average radius of the upper meniscus, m,rl= the average radius of the lower meniscus, m,g = the surface tension, N/m, andr = 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 calibr
