1、Designation: D1217 12Standard Test Method forDensity and Relative Density (Specific Gravity) of Liquids byBingham Pycnometer1This standard is issued under the fixed designation D1217; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision,
2、 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 This test method covers
3、 the measurement of the densityof pure hydrocarbons or petroleum distillates boiling between90 and 110C that can be handled in a normal fashion as aliquid at the specified test temperatures of 20 and 25C.1.2 This test method provides a calculation procedure forthe conversion of density to relative d
4、ensity (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 and corrosive tomaterials. Caution should be taken when handling mercury
5、 andmercury containing products. See the applicable product Ma-terial Safety Data Sheet (MSDS) for details and EPAswebsitehttp:/www.epa.gov/mercury/faq.htmfor addi-tional information. Users should be aware that selling mercuryand/or mercury containing products into your state or countrymay be prohib
6、ited by law.1.4 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.5 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 es
7、tablish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. Specific warningstatements are given in Section 7.2. Referenced Documents2.1 ASTM Standards:2D4052 Test Method for Density, Relative Density, and APIGravity of Liquids by Digital
8、 Density MeterE1 Specification for ASTM Liquid-in-Glass Thermometers3. Terminology3.1 Definitions:3.1.1 density, nmass per unit volume at a specifiedtemperature. D40523.1.2 relative density, nthe ratio of the density of amaterial at a stated temperature to the density of water at astated temperature
9、. D40524. Summary of Test Method4.1 The liquid sample is introduced into a pycnometer,equilibrated to the desired temperature, and weighed. Therelative density (specific gravity) or density is then calculatedfrom this weight and the previously determined weight ofwater that is required to fill the p
10、ycnometer at the sametemperature, both weights being corrected for the buoyancy ofair.5. Significance and Use5.1 Density is a fundamental physical property which can beused in conjunction with other properties to characterize purehydrocarbons and their mixtures.5.2 This test method was originally de
11、veloped for thedetermination of the density of the ASTM Knock Test Refer-ence Fuels n-heptane and isooctane, with an accuracy of1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.04.0D on Physical
12、and Chemical Methods.Current edition approved Nov. 1, 2012. Published December 2012. Originallyapproved in 1952. Last previous edition approved in 2007 as D121793(2007).DOI: 10.1520/D1217-12.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serv
13、iceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.*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. Unite
14、d States10.00003 g/mL. Although it is no longer employed extensivelyfor this purpose, this test method is useful whenever accuratedensities of pure hydrocarbons or petroleum fractions withboiling points between 90 and 110C are required.6. Apparatus6.1 Pycnometer, Bingham-type,3conforming to the dime
15、n-sions given in Fig. 1, constructed of borosilicate glass, andhaving a total weight not exceeding 30 g.6.2 Constant-Temperature Bath, provided with suitable py-cnometer holders or clips and means for maintaining tempera-tures constant to 60.01C in the desired range.6.3 Bath Thermometer, graduated i
16、n 0.1C subdivisions andstandardized for the ice point and the range of use to the nearest0.01C. ASTM Saybolt Viscosity Thermometer 17C as pre-scribed in Specification E1, designed for tests at 21.1C and25C, is recommended. A standardized platinum resistancethermometer may also be used, and offers th
17、e best means forobserving minute temperature changes in the bath. Whichevermeans are available, it must be realized that for most hydro-carbons the density coefficient is about 0.0008 units/C, andtherefore an error of 60.013C would cause an error of60.00001 in density.6.4 Hypodermic Syringe, 30-mL c
18、apacity, of chemicallyresistant glass, equipped with a 152-mm needle made ofstainless steel tubing as shown in Fig. 2.6.5 Draw-Off Needle, made of stainless steel tubing asshown in Fig. 2.6.6 Solvent-Cleaning Assembly, as shown in Fig. 3.6.7 Chromic Acid Cleaning Apparatus, similar to thatshown in F
19、ig. 4.6.8 Balance, capable of reproducing weighings within 0.1mg. Mechanical balances should have sensitivity which causesthe pointer to be deflected 2 or 3 scale divisions per 1 mg whencarrying a load of 30 g or less on each pan. The balance shouldbe located in a room shielded from drafts and fumes
20、 and inwhich the temperature changes between related weighings(empty and filled pycnometer) do not cause a significantchange in the ratio of the balance arms. Otherwise weighingsshall be made by the method of substitution, in which thecalibrated weights and pycnometer are alternately weighed onthe s
21、ame balance pan. The same balance shall be used for allrelated weighings.6.9 Weights, whose relative values are known to the nearest0.05 mg or better. The same set of weights shall be used for thecalibration of the pycnometer and the determination of densi-ties.7. Reagents and Materials7.1 Acetone(W
22、arningExtremely flammable. Use ad-equate ventilation.)7.2 Isopentane( WarningExtremely flammable. Avoidbuildup of vapors and remove all sources of ignition, especiallynon-explosion proof electrical apparatus.)7.3 Chromic Acid (Potassium Dichromate/Conc. SulfuricAcid)(WarningCauses severe burns. A re
23、cognized car-cinogen. Do not get in eyes, or on skin or clothing.)8. Preparation of Apparatus8.1 Thoroughly clean the pycnometer with hot chromic acidcleaning solution by means of the assembly shown in Fig. 4.Chromic acid solution (WarningSee 7.3) is the most effec-tive cleaning agent. However, surf
24、actant cleaning fluids havealso been used successfully. Mount the apparatus firmly andconnect the trap to the vacuum. Warm the necessary amount ofcleaning acid in the beaker, place the pycnometer on theground joint, and evacuate by opening the stopcock to vacuum.Fill the pycnometer with acid by turn
25、ing the stopcock, repeatseveral times or remove the filled pycnometer, and allow it tostand for several hours at 50 to 60C. Remove the acid from thepycnometer by evacuation, empty the acid from the trap, andflush the pycnometer with water. Cleaning should be made inthis manner whenever the pycnomete
26、r is to be calibrated orwhenever liquid fails to drain cleanly from the walls of thepycnometer or its capillary. Ordinarily, the pycnometer may be3The sole source of supply of the pycnometer known to the committee at thistime is Reliance Glass Co., 220 Gateway Rd., Bensenville, IL 60106-0825. If you
27、are aware of alternative suppliers, please provide this information to ASTMInternational Headquarters. Your comments will receive careful consideration at ameeting of the responsible technical committee,1which you may attend.FIG. 1 Bingham-Type Pycnometer, 25 mLD1217 122cleaned between determination
28、s by washing with a suitablesolvent, rinsing with pure, dry acetone, followed by isopentane,and vacuum drying.8.2 Transfer the pycnometer to the cleaner assembly shownin Fig. 3, with vacuum line and trap attached to the side tubeas indicated. Place the pycnometer on the cleaner with theupper hypoder
29、mic needle extending upward into thepycnometer, and press the edge of the ground joint on therubber stopper until the vacuum holds it in place. Draw out allthe liquid or sample. Immerse the lower end of the hypodermictube in a suitable solvent and draw 20 to 25 mL through thepycnometer. Leaving the
30、pycnometer in place, draw air throughit until it is dry. Clean the hypodermic syringe with the sameapparatus.9. Calibration of Pycnometer9.1 Proceeding as directed in Section 10, determine theweight of freshly-boiled and cooled distilled water (distilledfrom alkaline permanganate through a tin conde
31、nser) held bythe pycnometer when equilibrated to volume at the bathFIG. 2 Accessories for Bingham-Type PycnometerFIG. 3 Cleaner Assembly for Bingham-Type PycnometerD1217 123temperature to be used in the determination. Repeat until atleast three values agree to 60.2 mg.10. Procedure10.1 Using another
32、 25-mL pycnometer as a tare (Note 1),weigh the clean, dry pycnometer to 0.1 mg and record theweight.NOTE 1It is convenient to use the lightest of a set of pycnometers asa tare. For best results the treatment and environment of both pycnometerand tare should be identical for some time prior to weighi
33、ng.10.2 Cool the sample to 5 to 10C below the testtemperature, and fill the clean 30-mL hypodermic syringe.Transfer the sample to the pycnometer through the fillingneedle; avoid trapping air bubbles (WarningExtremelyflammable. Avoid buildup of vapors and remove all sources ofignition, especially non
34、-explosion proof electrical apparatus) inthe bulb or capillary of the pycnometer. If any are present, drawthem into the syringe where possible. Also remove with thesyringe or draw-off needle any liquid above the calibrationmark in the capillary or overflow reservoir. Dry the remainderwith a cotton f
35、iber pipe cleaner or cotton swab which has beendampened slightly with acetone.NOTE 2For work of highest accuracy on pure compounds, dissolvedair may be removed from the sample by repeated freezing and remeltingof the sample under vacuum in the pycnometer.10.3 Close the pycnometer with the glass stop
36、per andimmerse it to a point above the calibration mark in theconstant-temperature bath adjusted to a constancy of 60.01Cat the desired temperature. Periodically, or before the liquidexpands into the overflow chamber, remove the stopper, raisethe pycnometer sufficiently to expose the calibration mar
37、k toview, and readjust the liquid level to the mark by withdrawingliquid through the steel draw-off needle until expansion hasstopped, indicating that the liquid has reached the temperatureof the thermostat. Do not allow the liquid to expand more than10 mm above the calibration mark at any time, to
38、minimizeerrors caused by faulty drainage. Allow the contents to equili-brate an additional 10 min and draw the level down exactly tothe calibration line, avoiding parallax and using a magnifier, ifnecessary, to obtain good visibility. Remove any liquid adher-ing to the walls above the calibration ma
39、rk, with the draw-offneedle or pipe cleaner, depending upon the volatility of thesample. Portions in the overflow bulb may be removed with acotton swab moistened with acetone.10.4 Replace the glass stopper, remove the pycnometerfrom the bath, wash the outside surface with acetone, and drythoroughly
40、with a chemically clean, lint-free, slightly dampcloth. Place the pycnometer in or near the balance case for 20min and weigh to the nearest 0.1 mg. In atmospheres of lowhumidity (60 % or lower), drying the pycnometer by rubbingwith a dry cotton cloth will induce static charges equivalent toa loss of
41、 about 1 mg in the weight of the pycnometer. Thischarge need not be completely dissipated in less than 30 min.The use of about 0.1-mg radium bromide- or polonium-coatedfoil in the balance case, or maintaining the relative humidity at60 % or higher, aids in reducing weighing difficulties due tostatic
42、 charges.10.5 Record temperature of the balance, barometricpressure, and relative humidity.11. Calculation11.1 Calculate the true density of the sample as follows:Density, g/mL at C 5 Ws11da/ds! 2 da/dwt!dw/Ww11da/dw!2 da/dwt!where:Ws= weight in air of sample contained in the pycnometer atthe test t
43、emperature, g,Ww= weight in air of the water contained in the pycnometerat the calibration temperature, g,dw= density of water at the calibration temperature, asobtained from Table 1,da= density of air in balance case at the time of weighing,as calculated from 10.3,dwt= density of weights used in we
44、ighing the sample andwater (brass = 10.4 g/mL, stainless steel = 7.75g/mL), andds= approximate density of sample orWs3 d!/Ww11.2 The equation assumes that the weighings of the pyc-nometer empty and filled are made in such a short time intervalthat the air density has not changed. If significant chan
45、geFIG. 4 All-Glass Pycnometer Cleaner Assembly for Use with Hot Chromic Acid Cleaning SolutionD1217 124should occur, the calculated apparent weight of the sample, Ws,in this equation, must be corrected for the difference in airbuoyancy exerted on the pycnometer as follows:Ws5 W2PS2 Wp11da/2.2! (3)2d
46、a/dwt!)/11da2/2.2! 2 da2/dwt!where:W2PS= weight of pycnometer and contained sample undersecond or final air density,WP= weight of pycnometer in air of first density,da= density of air when weighing empty pycnometer,da2= density of air when weighing filled pycnometer,dwt= density of weights, and2.2 =
47、 borosilicate glass.Likewise, if the pycnometer, empty and filled with water forcalibration, is weighed under different air densities a similarcorrection for different air buoyancies shall be applied.11.3 Calculate the relative density (specific gravity) of thesample by dividing the density as obtai
48、ned in 11.1 by therelative density of water at the reference temperature obtainedfrom Table 1.11.4 Calculate the density of air in the balance room asfollows:Air density da!, g/mL (4)5 B 2 0.3783 Hp!0.000465!#/2731t!where:B = barometric pressure, mm Hg, corrected to 0C,H = relative humidity, decimal
49、 fraction,p = vapor pressure of water at temperature t, mm Hg, andt = room temperature, C.NOTE 3If this test method is to be used frequently, a considerableamount of calculation can be avoided by use of a gas density balance todetermine the air density. Weigh a sealed 250-mL glass bulb at severaldifferent air densities and plot the weight against the air density. Todetermine the air density at some later time, weigh the bulb and read theair density from the point on the curve corresponding to the weight.11.5 To calculate
