1、Designation: D 5188 09Standard Test Method forVapor-Liquid Ratio Temperature Determination of Fuels(Evacuated Chamber Method)1This standard is issued under the fixed designation D 5188; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revisio
2、n, 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 tem-perature at which the vapor formed from a selecte
3、d volume ofvolatile petroleum product saturated with air at 0 to 1C (32 to34F) produces a pressure of one atmosphere in an evacuatedchamber of fixed volume. This test method is applicable tosamples for which the determined temperature is between 36and 80C (97 and 176F) and the vapor-liquid ratio is
4、between8 to 1 and 75 to 1.NOTE 1When the vapor-liquid ratio is 20:1, the result is intended tobe comparable to the results determined by Test Method D 2533.NOTE 2This test method may also be applicable at pressures otherthan one atmosphere, but the stated precision may not apply.1.2 This test method
5、 is applicable to both gasoline andgasoline-oxygenate blends.1.2.1 Some gasoline-oxygenate blends may show a hazewhen cooled to 0 to 1C. If a haze is observed in 11.5, it shallbe indicated in the reporting of results. The precision and biasstatements for hazy samples have not been determined (seeNot
6、e 9).1.3 The values stated in SI units are to be regarded asstandard. The values given in parentheses are provided forinformation only.1.4 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 est
7、ablish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. For specificwarnings, see 7.2 and 8.1.1.2. Referenced Documents2.1 ASTM Standards:2D 2533 Test Method for Vapor-Liquid Ratio of Spark-Ignition Engine Fuels3D 2892 Test Method for
8、Distillation of Crude Petroleum(15-Theoretical Plate Column)D 4057 Practice for Manual Sampling of Petroleum andPetroleum Products3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 T(V/L = 20), nthe equilibrium temperature at whichthe partial pressure of a sample under test condi
9、tions is equalto 101.3 kPa (14.69 psia) and the vapor-liquid ratio is 20.3.1.2 vapor-liquid ratio of a fuel, nthe ratio at a specifiedtemperature and pressure of the volume of vapor in equilibriumwith liquid to the volume of sample charged, as a liquid, at 0C(32F).4. Summary of Test Method4.1 A know
10、n volume of chilled, air-saturated sample isintroduced into an evacuated, thermostatically controlled testchamber of known volume. The sample volume is calculated togive the desired vapor-liquid ratio for the chamber volume inuse. After injection, the chamber temperature is adjusted untila stable ch
11、amber pressure of 101.3 kPa (14.69 psia) isachieved.5. Significance and Use5.1 The tendency of a fuel to vaporize in automotive enginefuel systems is indicated by the vapor-liquid ratio of the fuel.5.2 Automotive fuel specifications generally include T(V/L = 20) limits to ensure products of suitable
12、 volatility perfor-mance. For high ambient temperatures, a fuel with a high valueof T(V/L = 20), indicating a fuel with a low tendency to vaporize,is generally specified; conversely for low ambient tempera-tures, a fuel with a low value of T(V/L = 20)is specified.1This test method is under the juris
13、diction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.08 on Volatility.Current edition approved July 1, 2009. Published August 2009. Originallyapproved in 1991. Last previous edition approved in 2004 as D 518804a.2For referenced ASTM st
14、andards, 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.3Withdrawn. The last approved version of this historical standard is referencedon ww
15、w.astm.org.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.6. Apparatus6.1 Apparatus suitable for use shall employ a small volumetest chamber incorporating a transduce
16、r for pressure measure-ments and associated equipment for thermostatically control-ling the chamber temperature, evacuating the test chamberprior to sample introduction, and cleaning and purging thechamber following the test. Critical elements of the apparatusshall meet the following specifications:
17、6.1.1 Test Chamber, constructed of stainless steel or alumi-num, designed to contain between 5 and 50 mL of liquid plusvapor with a tolerance of 61 % of the nominal capacity.NOTE 3The test chamber volumes of the instruments used for the1991 cooperative test program to determine the precision and bia
18、sstatements were between 5 and 15 mLof liquid plus vapor with a toleranceof 61 % of the nominal capacity.6.1.2 Pressure Transducer, minimum operational rangefrom 1 to 177 kPa (0 to 25.6 psia) with minimum resolution of0.1 kPa (0.01 psi) and minimum accuracy of 60.8 kPa (60.12psi). The pressure measu
19、rement system shall include associ-ated electronics and readout devices to display the resultingpressure reading.6.1.3 Heater, thermostatically controlled heater capable ofmaintaining the test chamber within 0.1C of the set tempera-ture for a minimum of 5 min.NOTE 4The use of automated instruments t
20、hat automatically adjustthe temperature, after sample injection, to give a pressure of 101.3 kPa(14.69 psia) is allowed.6.1.4 Platinum Resistance Thermometer, used to measurethe temperature of the test chamber, having a minimumtemperature range of 36 to 80C, minimum resolution of 0.1C(0.2F) and mini
21、mum accuracy of 60.1C (60.2F).6.2 Vacuum Pump, capable of reducing the pressure in thetest chamber to less than 0.01 kPa (0.001 psia).6.3 Syringes, (if required for sample introduction), gas-tight, 1- to 20-mL capacity with minimum accuracy andprecision of 61%.6.4 Bath, iced water or air, for chilli
22、ng the samples andsyringe (if required) to between 0 and 1C (32 to 34F).6.5 Pressure Measuring Device, capable of measuring localstation pressure with an accuracy of 0.20 kPa (0.03 psi) orbetter, at the same elevation relative to sea level as theapparatus in the laboratory.6.5.1 When a mercury manom
23、eter is not used as thepressure measuring device, the calibration of the pressuremeasuring device employed shall be periodically checked(with traceability to a nationally recognized standard) to ensurethat the device remains within the required accuracy specifiedin 6.5.6.6 McLeod Vacuum Gage or Cali
24、brated Electronic VacuumMeasuring Device for Calibration, to cover at least the rangefrom 0.01 to 0.67 kPa (0.1 to 5 mm Hg). The calibration of theelectronic vacuum measuring device shall be regularly verifiedin accordance with the annex section on Vacuum Sensors(A6.3) of Test Method D 2892.7. Reage
25、nts and Materials7.1 Purity of ReagentsUnless otherwise indicated, allreagents shall conform to the specifications of the Committeeon Analytical Reagents of the American Chemical Society4where such specifications are available. Lower purities can beused, provided it is first ascertained that the rea
26、gent is ofsufficient purity to permit its use without lessening the accu-racy of the determination. Reagents used for performancechecks (see 10.3) shall be of at least 99 % purity.7.2 n -pentane, (WarningFlammable, health hazard.)8. Sampling8.1 General:8.1.1 Conduct bulk sampling to obtain the labor
27、atorysamples in accordance with Practice D 4057 except forgasoline-oxygenate blends where water displacement is notused. The extreme sensitivity of T(V/L)measurements to lossesthrough evaporation and the resulting changes in compositionis such as to require the utmost precaution and the mostmeticulo
28、us care in the handling of samples. (WarningExtremely flammable, harmful if inhaled or ingested. Skinirritant on repeated contact. Aspiration hazard.)8.1.2 The size of the sample container from which thesample is taken shall be 1 L (1 qt). It shall be 70 to 80 % filledwith sample.8.1.3 The precision
29、 statement will be derived using samplesin 1-L (1-qt) containers. However, samples taken in containersof other sizes as prescribed in Practice D 4057 can be used ifit is recognized that the precision could be affected. In the caseof referee testing, the 1-L (1-qt) sample is mandatory.8.1.4 Perform t
30、he T(V/L)determination on the first testspecimen withdrawn from the sample container. Do not use theremaining sample in the container for a second T(V/L)deter-mination. If a second determination is necessary, obtain a newsample.8.1.5 Protect samples from excessive temperature prior totesting. This c
31、an be accomplished by storage in an appropriateice bath or refrigerator.8.1.6 Do not test samples stored in leaky containers. Discardand obtain a new sample if leaks are detected.8.2 Sampling TemperatureCool the sample container andcontents in an iced bath or refrigerator to between 0 and 1C(32 to 3
32、4F) prior to opening the sample container. Ensuresufficient time to reach this temperature by direct measurementof the temperature of a similar liquid in a like container placedin the cooling bath at the same time as the sample.8.3 Verification of Sample Container Filling:8.3.1 With the sample at a
33、temperature of 0 to 1C, take thecontainer from the cooling bath or refrigerator and wipe drywith absorbent material. If the container is not transparent,unseal it and using a suitable gage, confirm that the samplevolume equals 70 to 80 % of the container capacity (see Note5). If the sample is contai
34、ned in a transparent glass container,verify that the container is 70 to 80 % full by suitable means(see Note 5).4Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For Suggestions on the testing of reagents notlisted by the American Chemical Societ
35、y, see Annual Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.D51880928.3.2 Discard the sample if the container is filled to less than70 % by volume of the container c
36、apacity.8.3.3 If the container is filled to more than 80 % by volume,pour out enough sample to bring the container contents towithin the 70 to 80 % by volume range. Do not return anysample to the container once it has been withdrawn.NOTE 5For non-transparent containers, one way to confirm that thesa
37、mple volume equals 70 to 80 % of the container capacity is to use adipstick that has been pre-marked to indicate the 70 and 80 % containercapacities. The dipstick should be of such material that it shows wettingafter being immersed and withdrawn from the sample. To confirm thesample volume, insert t
38、he dipstick into the sample container so that ittouches the bottom of the container at a perpendicular angle, beforeremoving the dipstick. For transparent containers, using a marked ruler orby comparing the sample container to a like container which has the 70and 80 % levels clearly marked, has been
39、 found suitable.8.3.4 Reseal the container, if necessary, and return thesample container to the cooling bath or refrigerator.8.4 Air Saturation of the Sample in the Sample Container:8.4.1 Transparent Container OnlySince 8.3.1 does notrequire that the sample container be opened to verify thesample ca
40、pacity, it is necessary to unseal the cap momentarilybefore resealing it, so that samples in transparent containers aretreated the same as samples in non-transparent containers.8.4.2 With the sample again at a temperature of 0 to 1C,take the container from the cooling bath or refrigerator, wipe itdr
41、y with an absorbent material, remove the cap momentarily,taking care that no water enters, reseal and shake vigorously.Return it to the bath or refrigerator for a minimum of 2 min.9. Preparation of Apparatus9.1 Prepare the instrument for operation in accordance withthe manufacturers instructions.9.2
42、 Clean and dry the test chamber to avoid contaminationof the test sample.9.3 Prior to sample introduction, visually determine fromthe instrument display that the test chamber pressure is stableand does not exceed 0.1 kPa (0.01 psia). If the pressure is notstable or exceeds this value, check that the
43、 chamber containsno volatile materials from a previous sample, the seals aresatisfactory, the calibration of the transducer is correct, and theapparatus does not leak.9.4 If a syringe is used for introduction of the sample, chillthe syringe to between 0 and 1.0C (32 to 34F) in arefrigerator or ice b
44、ath before drawing in the sample. Thesyringe must be kept completely dry during this cooling. Placethe clean and dry syringe in a water tight plastic bag and placethe sealed bag in the ice bath or refrigerator maintained at 0 to1.0C (32 to 34F).9.5 Prior to introduction of the test specimen, set the
45、temperature of the test chamber to close to the expected result,if known; or 40C (104F), if unknown.10. Calibration10.1 Perform a calibration check of the pressure transducerat least once every six months, or sooner, as indicated by theperformance check (see 10.3). The calibration of the transduceri
46、s accomplished using two reference points, zero pressure, andambient barometric pressure.NOTE 6Pressure transducers can be sensitive to working temperature.Calibration should be performed at the test chamber temperature mostfrequently used.10.1.1 Connect a McLeod gage or a calibrated electronicvacuu
47、m measuring device to the vacuum source in line with thetest chamber. Apply vacuum to the test chamber. When thevacuum measuring device registers a pressure less than 0.1 kPa(0.8 mm Hg) adjust the indicator to zero or to the actualreading on the vacuum measuring device as dictated by theinstrument d
48、esign or manufacturers instructions.10.1.2 Open the test chamber to the atmosphere and observethe indicator reading. If the pressure reading is not equal to theambient barometric pressure, adjust the indicator span controluntil the appropriate reading is observed. Ensure that theinstrument is set to
49、 display the total pressure and not acalculated or corrected value.10.1.3 Repeat 10.1.1 and 10.1.2 until the zero and baromet-ric pressure read correctly without further adjustments.10.2 Calibrate the platinum resistance thermometer andindicator used to monitor the temperature of the test chamberat least every six months against a National Institute ofStandards and Technology (NIST) traceable thermometer.10.3 Check the performance of the instrument each day it isin use by running a sample consisting of air saturatedn-pentane, T(V/L = 20)= 36.1C
