1、Designation: D1481 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 or, in
2、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 densityof oils more viscous than 1
3、5 mm2/s (cSt) at 20 C, and ofviscous oils and melted waxes at elevated temperatures, but notat temperatures at which the sample would have a vaporpressure of 13.3 kPa (100 mmHg) or above.NOTE 1To determine the densities of less viscous liquids at 20 C or25 C use Test Method D1217.1.2 This test metho
4、d provides a calculation procedure forconverting density to relative density (specific gravity).1.3 WARNINGMercury has been designated by manyregulatory agencies as a hazardous material that can causecentral nervous system, kidney and liver damage. Mercury, orits vapor, may be hazardous to health an
5、d corrosive tomaterials. Caution should be taken when handling mercury andmercury containing products. See the applicable product SafetyData Sheet (SDS) for details and EPAs websitehttp:/www.epa.gov/mercury/faq.htmfor additional information.Users should be aware that selling mercury and/or mercuryco
6、ntaining products into your state or country may be prohib-ited by law.1.4 The values stated in SI units are to be regarded asstandard.1.4.1 ExceptionOther units of measurement are includedin this standard for information only.1.5 This standard does not purport to address all of thesafety concerns,
7、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 applica-bility of regulatory limitations prior to use.1.6 This international standard was developed in accor-dance with internationally recogn
8、ized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D1217 Test Method for
9、Density and Relative Density (Spe-cific Gravity) of Liquids by Bingham PycnometerD1250 Guide for Use of the Petroleum Measurement TablesD4052 Test Method for Density, Relative Density, and APIGravity of Liquids by Digital Density Meter3. Terminology3.1 Definitions:3.1.1 density, nmass per unit volum
10、e at a specifiedtemperature. D40523.1.2 relative density (specific gravity), nthe ratio of thedensity of a material at a stated temperature to the density ofwater at a stated temperature. D40524. Summary of Test Method34.1 The liquid is drawn into the bicapillary pycnometerthrough the removable siph
11、on arm and adjusted to volume atthe temperature of test, in such a manner that there ispractically no drainage in the unfilled tubing. After equilibra-tion at the test temperature, liquid levels are read, and thepycnometer is removed from the thermostated bath, cooled toroom temperature, and weighed
12、.4.2 Density or relative density (specific gravity), as desired,is then calculated from the volume at the test temperature andthe weight of the sample. The effect of air buoyancy is includedin the calculations.1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products, Li
13、quid Fuels, and Lubricants and is the direct responsibility ofSubcommittee D02.04.0D on Physical and Chemical Methods.Current edition approved June 1, 2017. Published July 2017. Originally approvedin 1957. Last previous edition approved in 2012 as D1481 12. DOI: 10.1520/D1481-17.2For referenced ASTM
14、 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.3For a more complete discussion of this procedure, see Lipkin, M. R., Mills, I.W.
15、, Martin, C. C., and Harvey, W. T., Analytical Chemistry, ANCHA, Vol 21, 1949,p. 504.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was devel
16、oped in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.15. Significance and
17、 Use5.1 Density is a fundamental physical property that can beused in conjunction with other properties to characterize boththe light and heavy fractions of petroleum and to access thequality of crude oils.5.2 Determination of the density or relative density ofpetroleum and its products is necessary
18、 for the conversion ofmeasured volumes to volumes at the standard temperatures of15 C.5.3 The determination of densities at the elevated tempera-tures of 40 C and 100 C is particularly useful in providing thedata needed for the conversion of kinematic viscosities incentistokes (mm2/s) to the corresp
19、onding dynamic viscositiesin centipoises (mPas).6. Apparatus6.1 Pycnometer4Aside-arm type of pycnometer conform-ing to the dimensions given in Fig. 1 and made of borosilicateglass. The weight shall not exceed 35 g without the side arm.6.2 RackA rack to use in filling the pycnometer (see Fig.2).6.3 C
20、onstant-Temperature OvenAn oven for use in fillingthe pycnometer. Any oven capable of holding the filling rack,and of maintaining a temperature of approximately 100 C, canbe used.6.4 Constant-Temperature BathA mixture of water andglycerin, or oil bath having a depth of at least 305 mm (12 in.)and pr
21、ovided with heating, stirring, and thermostating devicesadequate to maintain desired temperatures in the range from20 C to 100 C with an accuracy of 60.01 C.6.5 Bath ThermometersThermometers graduated in0.1 C subdivisions and standardized for the range of use to thenearest 0.01 C (ASTM Saybolt Visco
22、sity Thermometers 17Cto 22C are recommended). For most hydrocarbons, the densitycoefficient is about 0.0008 units/C, and therefore a tempera-ture error of 60.013 C would cause an error of 60.000 01 indensity.6.6 Pycnometer HolderA holder, as shown in Fig. 3,isrecommended for supporting the pycnomete
23、r in the bath. Asingle clamp device may be used.6.7 BalanceAbalance able to reproduce weighings within0.1 mg when carrying a load of 35 g or less on each pan. Thebalance shall be located in a room shielded from drafts andfumes and in which the temperature changes between relatedweighings (empty and
24、filled pycnometer) do not cause asignificant change in the ratio of the balance arms. Otherwise,weighings shall be made by the substitution method in whichthe calibrated weights and pycnometer are alternativelyweighed on the same balance pan. The same balance shall beused for all related weighings.6
25、.8 WeightsWeights shall be used whose relative valuesare known to the nearest 0.05 mg or better. The same set ofweights shall be used for the calibration of the pycnometer andthe determination of the densities, or the sets of weights shallbe calibrated relative to each other.4The sole source of supp
26、ly of the pycnometers known to the committee at thistime is Reliance Glass Co., 220 Gateway Rd., Bensenville, IL 60106-0825. If youare aware of alternative suppliers, please provide this information to ASTMInternational Headquarters. Your comments will receive careful consideration at ameeting of th
27、e responsible technical committee,1which you may attend.FIG. 1 PycnometerFIG. 2 Rack for Filling PycnometerD1481 1727. Reagents and Materials7.1 Acetone(WarningExtremely flammable. Use ad-equate ventilation.)7.2 Isopentane(WarningExtremely flammable. Avoidbuildup of vapors and remove all sources of
28、ignition, especiallynonexplosion-proof electrical apparatus.)7.3 Chromic Acid (Potassium Dichromate/Conc. SulfuricAcid)(WarningCauses severe burns. A recognized car-cinogen. Do not get in eyes, on skin or clothing.)7.4 Xylenes(WarningFlammable liquid. Aspirationhazard. May irritate skin, eyes, respi
29、ratory tract or digestivetract, or both. May cause central nervous system depression,liver and kidney damage, or exhibit reproductive and fetaleffects, or both.)8. Preparation of Apparatus8.1 Thoroughly clean the pycnometer and side arm with hotchromic acid cleaning solution (WarningSee 7.4). Chromi
30、cacid solution is the most effective cleaning agent. However,surfactant cleaning fluids have also been used successfully.Rinse well with distilled water; and dry at 105 C to 110 C forat least 1 h, preferably with a slow current of filtered airpassing through the pycnometer. Cleaning shall be done in
31、 thismanner whenever the pycnometer is to be calibrated orwhenever liquid fails to drain cleanly from the walls of thepycnometer or its capillary. Ordinarily, the pycnometer may becleaned between determinations by washing with a suitablesolvent, such as isopentane or xylenes, and vacuum drying. Ifac
32、etone is used as the wash liquid, the pycnometer should thenbe 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, and record the weight.9.2 Fill the pycnometer with freshly boiled distilled water.This may be
33、conveniently done by placing the pycnometer inthe holder with the side arm dipping into a sample cupcontaining water. Allow the pycnometer to fill by siphoning.Break the siphon by removing the side arm when the liquidlevel in the bulb arm of the pycnometer reaches 6 on the scale.9.3 Remove the side
34、arm which was used to fill thepycnometer and remove excess liquid from the capillary tip bywiping with a 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 thecapillaries below the liquid level in the bath.
35、 When the liquidlevel has reached equilibrium (not less than 15 min), read thescale to the nearest 0.2 small division at the liquid level in eacharm. After 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 5 min interval
36、s. When readings are constant,record.9.5 Remove the pycnometer from the bath and allow it tocome to room temperature. Rinse the outer surface withdistilled water, with acetone, then with redistilled xylenes, anddry thoroughly with a chemically clean lint-free cloth, slightlydamp with water.Allow to
37、stand a few minutes, and then weighto nearest 0.1 mg.NOTE 2In atmospheres of low humidity (60 % or lower), drying thepycnometer by rubbing with dry cotton cloth will induce static chargesequivalent to a loss of about 1 mg or more in the weight of thepycnometer. This charge may not be completely diss
38、ipated in less than12 h and can be detected by touching the pycnometer to the wire hook onthe balance and then drawing it away slowly. If the pycnometer exhibitsan attraction for the wire hook, it may be considered to have a staticcharge.9.6 Repeat the above, but break the siphon when water hasreach
39、ed the 3 mark in the bulb arm, and in the next experiment,at the 0 mark in the bulb arm. Obtain the apparent volume foreach filling by dividing the weight of water held by thepycnometer in each experiment by the density of water at thecalibration temperature t. Calibration shall be made at 20 C,40 C
40、, and 50 C. Prepare a calibration curve for 20 C byplotting the sum of the two scale readings versus the apparentvolume at 20 C. If the curve is not a straight line, and futureMetric Equivalentsin. mm in. mm in. mm12 3.212 12.7 158 41.314 6.4916 14.3 2316 55.7516 7.934 19.1 712 19138 9.5 112 38.1FIG
41、. 3 Pycnometer HolderD1481 173checks do not correct it, discard the pycnometer. The line shallnot be more than 0.0002 mLunit from any one determinedpoint.9.7 Corresponding calibration curves shall be made for40 C and 50 C. These calibration curves are checked usingthe following equation:V25 V111ct!
42、(1)where:V2= apparent volume at test temperature,V1= apparent volume at 20 C, andc = cubical coefficient of expansion of borosilicate glass(9.9 106/C).The calculated and determined curves at 40 C and 50 Cshould check to within 60.0002 mLunit at all points. Thecalibration curves for higher temperatur
43、es shall be obtained bycalculation.10. Procedure10.1 Weigh the clean, dry pycnometer, without the side arm,to 0.1 mg and record the weight.10.2 Place a 10 mL sample beaker in the wooden rack (Fig.2). Before attaching the side arm to the pycnometer, drain afew drops of sample through the side arm to
44、wet the insidesurface and reduce the chance of trapping air bubbles in thecapillary during the filling operation. Place the side arm on thepycnometer, and place the assembly on the rack with the sidearm dipping into the sample beaker as shown in Fig. 4.10.3 In filling the pycnometer with very viscou
45、s oils orhigh-melting waxes, place the whole filling assembly in ahot-air oven to facilitate filling. An oven at approximately100 C is usually hot enough for this purpose.10.4 Apply gentle suction to the bulb arm of the pycnometerto start the siphoning action. The suction must be gentle toavoid the
46、formation of bubbles. After siphoning is started,allow filling by siphoning to continue until the liquid level inthe bulb arm ceases to rise. Then remove the pycnometer fromthe rack and place in the thermostated bath, in the same tiltedposition, until the oil ceases to contract.At this point, place
47、thepycnometer in an upright position, and allow the liquid level inthe bulb arm to reach the upper portion of the calibratedcapillary, but not above 6.4. Stop siphoning by removing theside arm.NOTE 3With viscous oils, it will reduce drainage errors to fill to the6.0 to 6.4 mark, and it may be necess
48、ary to apply a little suction to the longarm during cooling to prevent the meniscus in the bulb arm from falling.Maintain the meniscus at about the same level in the long arm throughoutthe whole determination.FIG. 4 Pycnometer Filling AssemblyD1481 17410.5 After removing the side-arm cap from the sh
49、ort arm ofthe pycnometer, wipe the tip and ground joint of thepycnometer, and adjust it to an upright position in the thermo-stated bath. The bath liquid level shall be above the 6 mark onthe pycnometer and below the ground glass tip of the pycnom-eter.10.6 Allow 15 min for equilibrium to be obtained. After thestated 15 min time for coming to equilibrium, read the menis-cus levels in both arms of the pycnometer to the nearest 0.2 ofthe smallest scale division. Wait 5 min and check read
