1、Designation: D5188 13Standard Test Method forVapor-Liquid Ratio Temperature Determination of Fuels(Evacuated Chamber Method)1This standard is issued under the fixed designation D5188; 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.1. Scope*1.1 This test method covers the determination of the tem-perature at which the vapor formed from a selected
3、volume ofvolatile petroleum product saturated with air at 0 C to 1 C(32 F to 34 F) produces a pressure of one atmosphere in anevacuated chamber of fixed volume. This test method isapplicable to samples for which the determined temperature isbetween 36 C and 80 C (97 F and 176 F) and the vapor-liquid
4、 ratio is between 8 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 D2533.NOTE 2This test method may also be applicable at pressures otherthan one atmosphere, but the stated precision may not apply.1.2 This t
5、est method is applicable to both gasoline andgasoline-oxygenate blends.1.2.1 Some gasoline-oxygenate blends may show a hazewhen cooled to 0 C to 1 C. If a haze is observed in 12.5,itshall be indicated in the reporting of results. The precision andbias statements for hazy samples have not been determ
6、ined(see Note 10).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 st
7、andard to establish 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 Referenced Documents2.1 ASTM Standards:2D2533 Test Method for Vapor-Liquid Ratio of Spark-Ignition Engine Fuels (Withdrawn
8、2008)3D2892 Test Method for Distillation of Crude Petroleum(15-Theoretical Plate Column)D4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD6299 Practice for Applying Statistical Quality Assuranceand Control Charting Techniques to Evaluate AnalyticalMeasurement System Performance3.
9、 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 conditions 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 specifie
10、dtemperature and pressure of the volume of vapor in equilibriumwith liquid to the volume of sample charged, as a liquid, at0 C (32 F).4. Summary of Test Method4.1 A known volume of chilled, air-saturated sample isintroduced into an evacuated, thermostatically controlled testchamber of known volume.
11、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 chamber pressure of 101.3 kPa (14.69 psia) isachieved.5. Significance and Use5.1 The tendency of a fuel to vaporize in automotive eng
12、inefuel 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 volatility perfor-mance. For high ambient temperatures, a fuel with a high valueof T(V/L = 20), indicating a fuel with a low tende
13、ncy to vaporize,is generally specified; conversely for low ambienttemperatures, a fuel with a low value of T(V/L = 20)is specified.1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility ofSubcommittee D02.
14、08 on Volatility.Current edition approved Dec. 1, 2013. Published December 2013. Originallyapproved in 1991. Last previous edition approved in 2010 as D518810a. DOI:10.1520/D5188-13.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.o
15、rg. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,
16、100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States16. Apparatus6.1 Apparatus suitable for use shall employ a small volumetest chamber incorporating a transducer for pressure measure-ments and associated equipment for thermostatically control-ling the chamber temperat
17、ure, evacuating the test chamberprior to sample introduction, and cleaning and purging thechamber following the test. Critical elements of the apparatusshall meet the following specifications:6.1.1 Test Chamber, constructed of stainless steel oraluminum, designed to contain between 5 mL and 50 mL of
18、liquid plus vapor with a tolerance of 61 % of the nominalcapacity.NOTE 3The test chamber volumes of the instruments used for the1991 cooperative test program to determine the precision and biasstatements were between 5 mL and 15 mL of liquid plus vapor with atolerance of 61 % of the nominal capacity
19、.6.1.2 Pressure Transducer, minimum operational rangefrom 1 kPa to 177 kPa (0 psia to 25.6 psia) with minimumresolution of 0.1 kPa (0.01 psi) and minimum accuracy of60.8 kPa (60.12 psi). The pressure measurement system shallinclude associated electronics and readout devices to displaythe resulting p
20、ressure reading.6.1.3 Heater, thermostatically controlled heater capable ofmaintaining the test chamber within 0.1 C of the set tempera-ture for a minimum of 5 min.NOTE 4The use of automated instruments that automatically adjustthe temperature, after sample injection, to give a pressure of 101.3 kPa
21、(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 C to 80 C, minimum resolution of0.1 C (0.2 F) and minimum accuracy of 60.1 C (60.2 F).6.2 Vacuum Pump, capable of reducing the pressure in thetes
22、t chamber to less than 0.01 kPa (0.001 psia).6.3 Syringes, (if required for sample introduction), gas-tight, 1 mL to 20 mL capacity with minimum accuracy andprecision of 61%.6.4 Bath, iced water or air, for chilling the samples andsyringe (if required) to between 0 C and 1 C (32 F to 34 F).6.5 Press
23、ure 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 manometer is not used as thepressure measuring device, the calibration of the pressure
24、measuring 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 Calibrated Electronic VacuumMeasuring Device for Calibration, to cover at least the r
25、angefrom 0.01 kPa to 0.67 kPa (0.1 mm Hg to 5 mm Hg). Thecalibration of the electronic vacuum measuring device shall beregularly verified in accordance with the annex section onVacuum Sensors (A6.3) of Test Method D2892.7. Reagents and Materials7.1 Purity of ReagentsUnless otherwise indicated, allre
26、agents 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 reagent is ofsufficient purity to permit its use without lessening the accu
27、-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 laboratorysamples in accordance with Practice D4057 except forgasoline-oxygen
28、ate 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 mostmeticulous care in the handling of samples. (WarningExtremely flammable, harmful
29、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 %filled with sample.8.1.3 The precision statement will be derived using samplesin 1 L (1 qt) containers. Howev
30、er, samples taken in containersof other sizes as prescribed in Practice D4057 can be used if itis recognized that the precision could be affected. In the case ofreferee testing, the 1 L (1 qt) sample is mandatory.8.1.4 Perform the T(V/L)determination on the first testspecimen withdrawn from the samp
31、le container. Do not use theremaining sample in the container for a second T(V/L)determi-nation. If a second determination is necessary, obtain a newsample.8.1.5 Protect samples from excessive temperature prior totesting. This can be accomplished by storage in an appropriateice bath or refrigerator.
32、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 C and1 C (32 F to 34 F) prior to opening the sample container.Ensure sufficient time t
33、o reach this temperature by directmeasurement of the temperature of a similar liquid in a likecontainer placed in the cooling bath at the same time as thesample.8.3 Verification of Sample Container Filling:8.3.1 With the sample at a temperature of 0 C to 1 C, takethe container from the cooling bath
34、or refrigerator and wipe drywith absorbent material. If the container is not transparent,4Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For Suggestions on the testing of reagents notlisted by the American Chemical Society, see Annual Standards
35、 for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.D5188 132unseal it and using a suitable gage, confirm that the samplevolume equals 70 % to 80 % of the container capacity (seeNo
36、te 5). If the sample is contained in a transparent glasscontainer, verify that the container is 70 % to 80 % full bysuitable means (see Note 5).8.3.2 Discard the sample if the container is filled to less than70 % by volume of the container capacity.8.3.3 If the container is filled to more than 80 %
37、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 thesample volume equals 70 % to 80 % of the container capacity
38、 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 the dipstick into the sample container so that ittouch
39、es 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 70 %and 80 % levels clearly marked, has been found suitable.8.3.4 Reseal the container, if nece
40、ssary, 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 capacity, it is necessary to unseal the cap momentari
41、lybefore 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 C to1 C, take the container from the cooling bath or refrigerator,wipe it dry with an absorbent material, remove the capmome
42、ntarily, taking care that no water enters, reseal and shakevigorously. Return it to the bath or refrigerator for a minimumof 2 min.9. Preparation of Apparatus9.1 Prepare the instrument for operation in accordance withthe manufacturers instructions.9.2 Clean and dry the test chamber to avoid contamin
43、ationof 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 chamber containsno volatile materials from a pre
44、vious 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 samplespecimen, chill the syringe to between 0 C and 1.0 C (32 Fto 34 F) such as in a refrigerator or ice bath before drawing inthe s
45、ample specimen. Water contamination of the syringereservoir during this cooling procedure shall be avoided. Oneway to achieve this is by sealing the outlet of the syringe duringthe cooling process.9.5 Prior to introduction of the test specimen, set thetemperature of the test chamber to close to the
46、expected result,if known; or 40 C (104 F), if unknown.10. Calibration10.1 Perform a calibration check of the pressure transduceras indicated by the performance check (see 10.3). The calibra-tion of the transducer is accomplished using two referencepoints, zero pressure, and ambient barometric pressu
47、re.NOTE 6Calibration frequency of the pressure transducer may varywith instrument type and frequency of use. A calibration check of thepressure transducer at least once every six months is recommended.NOTE 7Pressure transducers can be sensitive to working temperature.Calibration should be performed
48、at the test chamber temperature mostfrequently used.10.1.1 Connect a McLeod gage or a calibrated electronicvacuum 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) ad
49、just the indicator to zero or to the actualreading on the vacuum measuring device as dictated by theinstrument design 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 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
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