1、Designation: D1481 12D1481 17Standard Test Method forDensity and Relative Density (Specific Gravity) of ViscousMaterials by Lipkin Bicapillary Pycnometer1This standard is issued under the fixed designation D1481; the number immediately following the designation indicates the year oforiginal adoption
2、 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 the determination of the density of oils more visco
3、us than 15 cStmm2 at 20C (mm/s (cSt) at20 C,2/s), and of viscous oils and melted waxes at elevated temperatures, but not at temperatures at which the sample would havea vapor pressure of 100 mm Hg (13 kPa) 13.3 kPa (100 mmHg) or above.NOTE 1To determine the densities of less viscous liquids at 2020
4、C or 25C25 C use Test Method D1217.1.2 This test method provides a calculation procedure for converting density to relative density (specific gravity).1.3 WARNINGMercury has been designated by many regulatory agencies as a hazardous material that can cause centralnervous system, kidney and liver dam
5、age. Mercury, or its vapor, may be hazardous to health and corrosive to materials. Cautionshould be taken when handling mercury and mercury containing products. See the applicable product Material Safety Data Sheet(MSDS)(SDS) for details and EPAs websitehttp:/www.epa.gov/mercury/faq.htmfor additiona
6、l information. Users should beaware that selling mercury and/or mercury containing products into your state or country may be prohibited by law.1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.4.1 ExceptionOther units of
7、measurement are included in this standard for information only.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 practices and determine the applic
8、ability of regulatorylimitations prior to use.1.6 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the Wor
9、ld Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D1217 Test Method for Density and Relative Density (Specific Gravity) of Liquids by Bingham PycnometerD1250 Guide for Use of the Petroleum Measurement TablesD4052 Test Method for Density, Rel
10、ative Density, and API Gravity of Liquids by Digital Density Meter3. Terminology3.1 Definitions:3.1.1 density, nmass per unit volume at a specified temperature. D40523.1.2 relative density (specific gravity), nthe ratio of the density of a material at a stated temperature to the density of waterat a
11、 stated temperature. D40521 This test method is under the jurisdiction of ASTM Committee D02 on Petroleum Products Products, Liquid Fuels, and Lubricants and is the direct responsibility ofSubcommittee D02.04.0D on Physical and Chemical Methods.Current edition approved Nov. 1, 2012June 1, 2017. Publ
12、ished December 2012July 2017. Originally approved in 1957. Last previous edition approved in 20072012 asD148102(2007).D1481 12. DOI: 10.1520/D1481-12.10.1520/D1481-17.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual B
13、ook of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.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 tech
14、nically possible to adequately depict all changes 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
15、 standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14. Summary of Test Method34.1 The liquid is drawn into the bicapillary pycnometer through the removable siphon arm and adjusted to volume at thetemperature of test, in such a ma
16、nner that there is practically no drainage in the unfilled tubing. After equilibration at the testtemperature, liquid levels are read, and the pycnometer is removed from the thermostated bath, cooled to room temperature, andweighed.4.2 Density or relative density (specific gravity), as desired, is t
17、hen calculated from the volume at the test temperature and theweight of the sample. The effect of air buoyancy is included in the calculations.5. Significance and Use5.1 Density is a fundamental physical property that can be used in conjunction with other properties to characterize both thelight and
18、 heavy fractions of petroleum and to access the quality of crude oils.5.2 Determination of the density or relative density of petroleum and its products is necessary for the conversion of measuredvolumes to volumes at the standard temperatures of 15C.15 C.5.3 The determination of densities at the el
19、evated temperatures of 4040 C and 100C100 C is particularly useful in providingthe data needed for the conversion of kinematic viscosities in centistokes (mm2/s) to the corresponding dynamic viscosities incentipoises (mPas).6. Apparatus6.1 Pycnometer4Aside-arm type of pycnometer conforming to the di
20、mensions given in Fig. 1 and made of borosilicate glass.The weight shall not exceed 35 g 35 g without the side arm.6.2 RackA rack to use in filling the pycnometer (see Fig. 2).6.3 Constant-Temperature OvenAn oven for use in filling the pycnometer. Any oven capable of holding the filling rack, andof
21、maintaining a temperature of approximately 100C,100 C, can be used.6.4 Constant-Temperature BathAmixture of water and glycerin, or oil bath having a depth of at least 305 mm (12 in.) 305 mm(12 in.) and provided with heating, stirring, and thermostating devices adequate to maintain desired temperatur
22、es in the range from2020 C to 100C100 C with an accuracy of 60.01C.60.01 C.3 For a more complete discussion of this procedure, see Lipkin, M. R., Mills, I. W., Martin, C. C., and Harvey, W. T., Analytical Chemistry, ANCHA, Vol 21, 1949, p.504.4 The sole source of supply of the pycnometers known to t
23、he committee at this time is Reliance Glass Co., 220 Gateway Rd., Bensenville, IL 60106-0825 have been foundsatisfactory. 60106-0825. If you are aware of alternative suppliers, please provide this information to ASTM International Headquarters. Your comments will receive carefulconsideration at a me
24、eting of the responsible technical committee,1 which you may attend.FIG. 1 PycnometerD1481 1726.5 Bath ThermometersThermometers graduated in 0.1C0.1 C subdivisions and standardized for the range of use to thenearest 0.01C0.01 C (ASTM Saybolt Viscosity Thermometers 17C to 22C are recommended). For mo
25、st hydrocarbons, thedensity coefficient is about 0.0008 units/C, and therefore a temperature error of 60.013C60.013 C would cause an error of60.000 01 in density.6.6 Pycnometer HolderA holder, as shown in Fig. 3, is recommended for supporting the pycnometer in the bath. A singleclamp device may be u
26、sed.6.7 BalanceA balance able to reproduce weighings within 0.1 mg 0.1 mg when carrying a load of 35 g 35 g or less on eachpan. The balance shall be located in a room shielded from drafts and fumes and in which the temperature changes between relatedweighings (empty and filled pycnometer) do not cau
27、se a significant change in the ratio of the balance arms. Otherwise, weighingsshall be made by the substitution method in which the calibrated weights and pycnometer are alternatively weighed on the samebalance pan. The same balance shall be used for all related weighings.6.8 WeightsWeights shall be
28、 used whose relative values are known to the nearest 0.05 mg 0.05 mg or better. The same set ofweights shall be used for the calibration of the pycnometer and the determination of the densities, or the sets of weights shall becalibrated relative to each other.7. Reagents and Materials7.1 Acetone(War
29、ningWarningExtremely Extremely flammable. Use adequate ventilation.)7.2 Isopentane(Warning WarningExtremely Extremely flammable. Avoid buildup of vapors and remove all sources ofignition, especially nonexplosion-proof electrical apparatus.)7.3 Chromic Acid (Potassium Dichromate/Conc. Sulfuric Acid)(
30、WarningWarningCausesCauses severe burns. Arecognized carcinogen. Do not get in eyes, on skin or clothing.)7.4 Xylenes(WarningWarningFlammable Flammable liquid. Aspiration hazard. May irritate skin, eyes, respiratory tractor digestive tract, or both. May cause central nervous system depression, liver
31、 and kidney damage, or exhibit reproductive and fetaleffects, or both.)8. Preparation of Apparatus8.1 Thoroughly clean the pycnometer and side arm with hot chromic acid cleaning solution (WarningWarningSeeSee 7.4).Chromic acid solution is the most effective cleaning agent. However, surfactant cleani
32、ng fluids have also been used successfully.Rinse well with distilled water; and dry at 105105 C to 110C110 C for at least 1 h, 1 h, preferably with a slow current of filteredair passing through the pycnometer. Cleaning shall be done in this manner whenever the pycnometer is to be calibrated or whene
33、verliquid fails to drain cleanly from the walls of the pycnometer or its capillary. Ordinarily, the pycnometer may be cleaned betweenFIG. 2 Rack for Filling PycnometerD1481 173determinations by washing with a suitable solvent, such as isopentane or xylenes, and vacuum drying. If acetone is used as t
34、hewash liquid, the pycnometer should then be rinsed with isopentane or xylenes.9. Calibration of Pycnometer9.1 Weigh the clean, dry pycnometer (without the side arm) to the nearest 0.1 mg, 0.1 mg, and record the weight.9.2 Fill the pycnometer with freshly boiled distilled water. This may be convenie
35、ntly done by placing the pycnometer in theholder with the side arm dipping into a sample cup containing water. Allow the pycnometer to fill by siphoning. Break the siphonby removing the side arm when the liquid level in the bulb arm of the pycnometer reaches 6 on the scale.9.3 Remove the side arm wh
36、ich was used to fill the pycnometer and remove excess liquid from the capillary tip by wiping witha small piece of absorbent paper.9.4 Place the pycnometer in the holder in the constant-temperature bath at temperature t with the liquid level in the capillariesbelow the liquid level in the bath. When
37、 the liquid level has reached equilibrium (not less than 15 min), 15 min), read the scaleto the nearest 0.2 small division at the liquid level in each arm. After 5 min, 5 min, read the liquid level again. If the sum of thescale readings in each reading differs by more than 60.04, repeat readings at
38、5-min5 min intervals. When readings are constant,record.Metric Equivalentsin. mm in. mm in. mm12 3.2 12 12.7 158 41.314 6.4 916 14.3 2316 55.7516 7.9 34 19.1 712 19138 9.5 112 38.1FIG. 3 Pycnometer HolderD1481 1749.5 Remove the pycnometer from the bath and allow it to come to room temperature. Rinse
39、 the outer surface with distilledwater, with acetone, then with redistilled xylenes, and dry thoroughly with a chemically clean lint-free cloth, slightly damp withwater. Allow to stand a few minutes, and then weigh to nearest 0.1 mg.0.1 mg.NOTE 2In atmospheres of low humidity (60 % or lower), drying
40、 the pycnometer by rubbing with dry cotton cloth will induce static charges equivalentto a loss of about 1 mg 1 mg or more in the weight of the pycnometer.This charge may not be completely dissipated in less than 12 h h and can be detectedby touching the pycnometer to the wire hook on the balance an
41、d then drawing it away slowly. If the pycnometer exhibits an attraction for the wire hook,it may be considered to have a static charge.9.6 Repeat the above, but break the siphon when water has reached the 3 mark in the bulb arm, and in the next experiment, atthe 0 mark in the bulb arm. Obtain the ap
42、parent volume for each filling by dividing the weight of water held by the pycnometerin each experiment by the density of water at the calibration temperature t. Calibration shall be made at 20, 40,20 C, 40 C, and50C.50 C. Prepare a calibration curve for 20C20 C by plotting the sum of the two scale
43、readings versus the apparent volumeat 20C.20 C. If the curve is not a straight line, and future checks do not correct it, discard the pycnometer. The line shall not bemore than 0.00020.0002 mL mL/unit unit from any one determined point.9.7 Corresponding calibration curves shall be made for 4040 C an
44、d 50C.50 C. These calibration curves are checked usingthe following equation:V25V111ct! (1)where:where:V2 = apparent volume at test temperature,V1 = apparent volume at 20C, andV1 = apparent volume at 20 C, andc = cubical coefficient of expansion of borosilicate glass (9.9 106/C).The calculated and d
45、etermined curves at 4040 C and 50C50 C should check to within 60.000260.0002 mL mL/unit unitat all points. The calibration curves for higher temperatures shall be obtained by calculation.10. Procedure10.1 Weigh the clean, dry pycnometer, without the side arm, to 0.1 mg 0.1 mg and record the weight.1
46、0.2 Place a 10-mL10 mL sample beaker in the wooden rack (Fig. 2). Before attaching the side arm to the pycnometer, draina few drops of sample through the side arm to wet the inside surface and reduce the chance of trapping air bubbles in the capillaryduring the filling operation. Place the side arm
47、on the pycnometer, and place the assembly on the rack with the side arm dippinginto the sample beaker as shown in Fig. 4.10.3 In filling the pycnometer with very viscous oils or high-melting waxes, place the whole filling assembly in a hot-air ovento facilitate filling. An oven at approximately 100C
48、100 C is usually hot enough for this purpose.10.4 Apply gentle suction to the bulb arm of the pycnometer to start the siphoning action. The suction must be gentle to avoidthe formation of bubbles. After siphoning is started, allow filling by siphoning to continue until the liquid level in the bulb a
49、rmceases to rise. Then remove the pycnometer from the rack and place in the thermostated bath, in the same tilted position, until theoil ceases to contract.At this point, place the pycnometer in an upright position, and allow the liquid level in the bulb arm to reachthe upper portion of the calibrated capillary, but not above 6.4. Stop siphoning by removing the side arm.NOTE 3With viscous oils, it will reduce drainage errors to fill to the 6.0 to 6.4 mark, and it may be necessary
