1、Designation:D 941-88 AMERICAN SOCIETY FOR TESTING AND MATERIALS 1916 Race SI.,Philadelphia.Pa.19103 Reprinted from the Annual Book of ASTM Standards.Copyright ASTM If not listed in the current combined index.will appear in the next edition.An An&an National Standard Standard Test Method for Density
2、and Relative Density(Specific Gravity)of Liquids by Lipkin Bicapillary Pycnometer This standard is issued under the fixed designation D 941;the number immediately following the designation indicates the year of original adoption or,in the case of revision,the year of last revision.A number in parent
3、heses indicates the year of last reapprovat.A superscript epsilon(3 indicates an editorial change since the last revision or reapproval.This standard has been approvedfor use by agencies of the Department of Defense to replace Method 402 of Test Method Standard No 791b.Consult the DOD Index of Speci
4、jcations and Standards for the speci/ic year of issue which has been adopted by the Department of Defense.1.Scope 1.1 This test method covers the measurement of the density of any hydrocarbon material that can be handled in a normal fashion as a liquid at the specified test temperatures of 20 to 25C
5、.Its application is restricted to liquids having vapor pressures less than 80 kPa(600 mm Hg)and having viscosities less than 15 mm/s(cst)at 20C.Ii2 Two procedures are covered as follows:1.2.1 Procedure A,for pure compounds and mixtures which are not highly volatile.1.2.2 Procedure B,for highly volat
6、ile mixtures.1.3 This test method provides a calculation procedure for converting density to relative density.1.4 This standard may involve hazardous materials,oper-ations,and equipment.This standard does not purport to address all of the.safety problems associated with its use.It is the responsibil
7、ity of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.Specific hazard statements are given in Notes 1,2,6 and Annex Al,2.Referenced Documents 2.1 ASTM Standards:D 1250 Petroleum Measurement Tables2
8、 E 1 Specification for ASTM Thermometers3 3.Teiminology 3.1 density-mass per unit volume.3.1.1 Discussion-In this test method,the measurement is at any given temperature and the units are grams per millilitre.3.1.2 relative density-the ratio of the density of a mate-rial at a stated temperature to t
9、he density of water at a stated temperature,r This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricanfs and is the direct responsibility of Subcom-mittee DO2.04 on Hydrocarbon Analysis.Current edition approved Ott 31,-1988.Published December 1988.Originall
10、y published as D 941-47.Last previous edition D 941-83.2 Annual Book of ASTM Standards,VolO5.0 1.Annual Book of ASTM Standards,Vols 05.03 and 14.01.4.Summary of Test Method4 4.1 The liquid sample is drawn into the pycnometer and weighed.It is then equilibrated at the test temperature,and the positio
11、ns of the liquid levels are observed.The density or relative density of the sample is then calculated from its weight,a calibration factor proportional to an equal volume of water,and a term that corrects for the buoyancy of air.5.Significance and Use 5.1 Density is a fundamental physical property w
12、hich can be used in conjunction with other properties to characterize both the light and heavy fractions of petroleum and to assess 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 measured volumes to volu
13、mes at the standard temperatures of 15C or 60F.6.Apparatus 6.-l Pycnometer-A pycnometer conforming to the di-mensions given in Fig.1,constructed of borosilicate glass,and having a total weight not exceeding 30 g.6.2 Constant-Temperature Bath-A water bath having a depth of at least 12 in.(305 mm),pro
14、vided with means for maintaining a temperature of 20 f 0.02”C or 25+-0.02”C.6.3 Bath Thermometer-No suitable ASTM Celsius ther-mometers are available;ASTM Kinematic Viscosity Ther-mometers 44F and 45F designed for tests at 68F(20C)and 77F(25C)and conforming to the requirements prescribed in Specific
15、ation E 1 are therefore specified.Ice point and bore corrections must be known to the nearest 0.02”F.In use,the thermometers must be immersed to a point at least 2F above the test temperature,6.4 Pycnometer Holder-Figure 2 shows the structural details of the holder proper.It can be made of brass.or
16、any other available metal that can be hard-or soft-soldered and that will not corrode in the thermostat liquid.Figure 3 illustrates a convenient mounting for suspending the holders in the thermostat.It consists of a bra&bar/8 in.(3.2 mm)in thickness by 1 in.(25 mm)in width,of a length suitable for 4 For a more complete discussion of this method,see Davidson,J.A.,Harvey,T.,Kurtz,S.S.,Jr.,Lipkin,M.R.,“Pycnometer for Volatile Liquids,”Indusfrial andEngineering Chemistry,Analytical Edition,IENAA Vol