1、Designation: D287 12bStandard Test Method forAPI Gravity of Crude Petroleum and Petroleum Products(Hydrometer Method)1This standard is issued under the fixed designation D287; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the yea
2、r 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 by means ofa glass hydrometer in conjunction with a series of calculat
3、ionsof the API gravity of crude petroleum and petroleum productsnormally handled as liquids and having a Reid vapor pressure(Test Method D323) of 101.325 kPa (14.696 psi) or less.Gravities are determined at 60F (15.56C), or converted tovalues at 60F, by means of Adjunct to D1250 Guide forPetroleum M
4、easurement Tables (API MPMS Chapter 11.1).These tables are not applicable to nonhydrocarbons or essen-tially pure hydrocarbons such as the aromatics.1.2 The initial values obtained are uncorrected hydrometerreadings and not density measurements. Values are measuredon a hydrometer at either the refer
5、ence temperature or atanother convenient temperature, and readings corrected for themeniscus effect, the thermal glass expansion effect, alternatecalibration temperature effects and to the reference temperatureby means of volume correction tables.1.3 The hydrometer readings determined shall be recor
6、dedbefore performing any calculations. Then the calculationsrequired in Section 9 shall be performed and documentedbefore using the final result in a subsequent calculationprocedure (measurement ticket calculation, meter factor calcu-lation, or base prover volume determination).1.4 The values stated
7、 in inch-pound units are to be regardedas standard. The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its use.
8、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. For specificwarning statement, see 8.3.2. Referenced Documents2.1 ASTM Standards:2D323 Test Method for Vapor Pressure of
9、 Petroleum Prod-ucts (Reid Method)D1250 Guide for Use of the Petroleum Measurement TablesD1298 Test Method for Density, Relative Density, or APIGravity of Crude Petroleum and Liquid Petroleum Prod-ucts by Hydrometer Method (API MPMS Chapter 9.1)D6822 Test Method for Density, Relative Density, and AP
10、IGravity of Crude Petroleum and Liquid Petroleum Prod-ucts by Thermohydrometer Method (API MPMS Chapter9.3)E1 Specification for ASTM Liquid-in-Glass ThermometersE100 Specification for ASTM Hydrometers2.2 EI Standards:3Specifications for IP Standard ThermometersIP Specifications for Petroleum Hydrome
11、ters2.3 API Standards:4MPMS Chapter 9.1 Test Method for Density, Relative Den-sity, or API Gravity of Crude Petroleum and LiquidPetroleum Products by Hydrometer Method (ASTM TestMethod D1298)MPMS Chapter 9.3 Test Method for Density, Relative Den-sity, and API Gravity of Crude Petroleum and LiquidPet
12、roleum Products by Thermohydrometer Method(ASTM Test Method D6822)MPMS Chapter 11.1 Temperature and Pressure VolumeCorrection Factors for Generalized Crude Oils, RefinedProducts, and Lubricating Oils (Adjunct toASTM D1250)2.4 ASTM Adjuncts:Adjunct to D1250 Guide for Petroleum Measurement Tables(API
13、MPMS Chapter 11.1)51This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and the API Committee on Petroleum Measure-ment, and is the direct responsibility of Subcommittee D02.02 /COMQ, the jointASTM-API Committee on Hydrocarbon Measurement for Custody
14、Transfer (JointASTM-API).Current edition approved June 1, 2012. Published October 2012. Originallyapproved in 1928. Last previous edition approved in 2012 as D28712a. DOI:10.1520/D0287-12B.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at servic
15、eastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from Energy Institute, 61 New Cavendish St., London, WIG 7AR,U.K., http:/www.energyinst.org.4Available from American Petroleum Institute (API), 1220 L. St., NW,
16、Wash-ington, DC 20005-4070, http:/www.api.org.5Available from ASTM International Headquarters. Order Adjunct No.ADJD1250. Original adjunct produced in 1983.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Consho
17、hocken, PA 19428-2959, United States.3. Terminology3.1 Definitions:3.1.1 API gravity, na special function of relative density60/60F (15.56/15.56C), represented by:API 5 141.5 / relative density 60/60F!# 2 131.5 (1)No statement of reference temperature is required, since60F is included in the definit
18、ion.3.1.2 hydrometer reading, nthe point on the hydrometerscale at which the surface of the liquid cuts the scale.3.1.2.1 DiscussionIn practice for transparent fluids thiscan be readily determined by aligning the surface of the liquidon both sides of the hydrometer and reading the Hydrometerscale wh
19、ere these surface readings cut the scale (HydrometerReading Observed). For nontransparent fluids the point atwhich the liquid surface cuts the Hydrometer scale cannot bedetermined directly and requires a correction (Meniscus Cor-rection). The value represented by the point (Meniscus Read-ing) at whi
20、ch the liquid sample rises above the main surface ofthe liquid subtracted from the value represented by where themain surface of the liquid cuts the Hydrometer scale is theamount of the correction or Meniscus correction. This menis-cus correction is documented and then subtracted from thevalue repre
21、sented by the Meniscus Reading to yield theHydrometer Reading corrected for the Meniscus (HydrometerReading Observed, Meniscus Corrected).3.1.3 specific gravity, nhistorical term, no longer used,which has been replaced by relative density.4. Summary of Test Method4.1 This test method is based on the
22、 principle that thegravity of a liquid varies directly with the depth of immersionof a body floating in it. The floating body, which is graduatedby API gravity units in this test method, is called an APIhydrometer.4.2 The API gravity is read by observing the freely floatingAPI hydrometer and noting
23、the graduation nearest to theapparent intersection of the horizontal plane surface of theliquid with the vertical scale of the hydrometer, after tempera-ture equilibrium has been reached. The temperature of thesample is read from a separate accurate ASTM thermometer inthe sample.4.3 The observed hyd
24、rometer reading is corrected for themeniscus effect, the thermal glass expansion effect, alternatecalibration temperature effects and reduced to the referencetemperature by means of the volume correction tables. Ifnecessary, the hydrometer cylinder and its contents are placedin a constant temperatur
25、e bath to avoid excessive temperaturevariation during the test.5. Significance and Use5.1 Accurate determination of the gravity of petroleum andits products is necessary for the conversion of measuredvolumes to volumes at the standard temperature of 60F(15.56C).5.2 This procedure is most suitable fo
26、r determining the APIgravity of low viscosity transparent liquids. This test methodcan also be used for viscous liquids by allowing sufficient timefor the hydrometer to reach temperature equilibrium, and foropaque liquids by employing a suitable meniscus correction.Additionally for both transparent
27、and opaque fluids the read-ings shall be corrected for the thermal glass expansion effectbefore correcting to the reference temperature.5.3 When used in connection with bulk oil measurements,volume correction errors are minimized by observing thehydrometer reading at a temperature as close to refere
28、ncetemperature as feasible.5.4 Gravity is a factor governing the quality of crude oils.However, the gravity of a petroleum product is an uncertainindication of its quality. Correlated with other properties,gravity can be used to give approximate hydrocarbon compo-sition and heat of combustion.5.5 Gr
29、avity is an important quality indicator for automotive,aviation and marine fuels, where it affects storage, handlingand combustion.6. Apparatus6.1 Hydrometers, of glass, graduated in degrees API aslisted in Table 1 and conforming to Specification E100.6.1.1 The user should ascertain that the instrum
30、ents used forthis method conform to the requirements set out above withrespect to materials, dimensions, and scale errors. In caseswhere the instrument is provided with a calibration certificateissued by a recognized standardizing body, the instrument isclassed as certified and the appropriate corre
31、ctions for themeniscus effect, the thermal glass expansion effect, and alter-native calibration temperature effects shall be applied to theobserved readings prior to corrections. Instruments that satisfythe requirements of this test method, but are not provided witha recognized calibration certifica
32、te, are classed as uncertified.6.2 Thermometers, having a range from 5 to +215F andconforming to the requirements for Thermometer 12F asprescribed in Specification E1 or Thermometer 64F of theSpecification for IP Standard Thermometers.6.2.1 Alternate measuring devices or systems may be used,provided
33、 that the total uncertainty of the calibrated system is nogreater than when using liquid-in-glass thermometers. Thestated repeatability and reproducibility values are not appli-cable if alternate fluids are used in the liquid-in-glass thermom-eters.NOTE 1TheASTM Gravity Thermometer 12F has 0.5F subd
34、ivisionsand allowable 60.25F scale error.6.3 Hydrometer Cylinder, clear glass, plastic, or metal (see6.3.1). The inside diameter of the cylinder shall be at least 25mm greater than the outside diameter of the hydrometer and theheight shall be such that the appropriate hydrometer floats inthe test po
35、rtion with at least 25 mm clearance between thebottom of the hydrometer and the bottom of the cylinder.TABLE 1 Available Hydrometers Scaled, Degrees APIDesignation TypeAPI Range, deg ScaleSeries Total Each Unit Division Error1H to 10H long plain 1 to 101 12 0.1 0.121H to 40H short plain 0 to 101 6 0
36、.1 0.251H to 60H thermo 1 to 101 12 0.1 0.171H to 74H thermo 1 to 41 12 0.1 0.1Athermo 15 to 51 8AEight-degree range thermohydrometers are available.D287 12b26.3.1 Hydrometer cylinders constructed of plastic materialsshall be resistant to discoloration or attack by oil samples andshall not affect th
37、e material being tested.They shall not becomeopaque under prolonged exposure to sunlight.7. Temperature of Test7.1 The gravity determined by the hydrometer method ismost accurate at or near the standard temperature of 60F(15.56C). Use this or any other temperature between 0 and195F (18 and + 90C) fo
38、r the test, so far as it is consistentwith the type of sample and necessary limiting conditionsshown in Table 2.8. Procedure8.1 For referee testing, use the long plain form of hydrom-eter (1H to 10H). For field testing, use the thermohydrometermethod in Test Method D6822 (API MPMS Chapter 9.3).8.2 A
39、djust the temperature of the sample in accordance withTable 2. For field testing, test temperatures other than thoselisted in Table 2 may be used. The hydrometer cylinder shall beapproximately the same temperature as the sample to be tested.8.3 Transfer the sample into the clean hydrometer cylinderw
40、ithout splashing, so as to avoid the formation of air bubblesand to reduce to a minimum the evaporation of the lowerboiling constituents of the more volatile samples. (WarningExtremely flammable. Vapors may cause flash fire.) For themore volatile samples, transfer to the hydrometer cylinder bysiphon
41、ing. (Do not start the siphon by mouth.) Use a rubberaspirator bulb. Remove any air bubbles formed, after they havecollected on the surface of the sample, by touching them witha piece of clean filter paper or other suitable means beforeinserting the hydrometer. For field testing, make the gravitymea
42、surement directly in the sampling thief. Place the cylindercontaining the sample in a vertical position in a location freefrom air currents. Take precautions to prevent the temperatureof the sample from changing appreciably during the timenecessary to complete the test. During this period, the tempe
43、ra-ture of the surrounding medium should not change more than5F (2C).8.4 Lower the hydrometer gently into the sample and, whenit has settled, depress it about two scale divisions into the liquidand then release it; keep the rest of the stem dry, as unnecessaryliquid on the stem changes the effective
44、 weight of the instru-ment, and so affects the reading obtained. With samples of lowviscosity, a slight spin imparted to the instrument on releasingassists in bringing it to rest, floating freely away from the wallsof the hydrometer cylinder. Allow sufficient time for thehydrometer to become complet
45、ely stationary and for all airbubbles to come to the surface. This is particularly necessary inthe case of the more viscous samples.8.5 When the hydrometer has come to rest, floating freely,and the temperature of the sample is constant to 0.2F (0.1C),read the hydrometer to the nearest scale division
46、. The correctreading is that point on the hydrometer scale at which thesurface of the liquid cuts the scale. Determine this point byplacing the eye slightly below the level of the liquid and slowlyraising it until the surface, first seen as a distorted ellipse,appears to become a straight line cutti
47、ng the hydrometer scale.8.6 To make a reading with nontransparent liquids, observethe point on the hydrometer scale to which the sample risesabove its main surface, placing the eye slightly above the planesurface of the liquid. This reading requires a correction.Determine this correction for the par
48、ticular hydrometer in useby observing the height above the main surface of the liquid towhich the sample rises on the hydrometer scale when thehydrometer in question is immersed in a transparent liquidhaving a surface tension similar to that of a sample under test.8.7 Observe the temperature of the
49、sample to the nearest0.25F (0.1C) immediately before and after the observation ofthe gravity, the liquid in the cylinder being thoroughly butcautiously stirred with the thermometer (Note 2), and thewhole of the mercury thread being immersed. Should thesetemperature readings differ by more than 1F (0.5C), repeatthe temperature and gravity observations when the temperatureof the sample has become more stable. Record the mean of thethermometer reading before and after the final hydrometerreading, to the nearest 1F, as the temperature of the t
