1、Designation: D4308 12D4308 13 An American National StandardStandard Test Method forElectrical Conductivity of Liquid Hydrocarbons by PrecisionMeter1This standard is issued under the fixed designation D4308; the number immediately following the designation indicates the year oforiginal adoption or, i
2、n the case of revision, 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
3、This test method covers and applies to the determination of the “rest” electrical conductivity of aviation fuels and othersimilar low-conductivity hydrocarbon liquids in the range from 0.1 to 2000 pS/m (see 3.1.2). This test method can be used in thelaboratory or in the field.1.2 The values stated i
4、n SI units are to be regarded as standard. No other units of measurement are included in this standard.1.3 WARNINGMercury has been designated by many regulatory agencies as a hazardous material that can cause centralnervous system, kidney and liver damage. Mercury, or its vapor, may be hazardous to
5、health and corrosive to materials. Cautionshould be taken when handling mercury and mercury containing products. See the applicable product Material Safety Data Sheet(MSDS) for details and EPAs websitehttp:/www.epa.gov/mercury/faq.htmfor additional information. Users should be awarethat selling merc
6、ury and/or mercury containing products into your state or country may be prohibited by law.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practi
7、ces and determine the applicability of regulatorylimitations prior to use. For specific warning statements, see 7.1.1, 7.2, 8.3, and Annex A1.2. Referenced Documents2.1 ASTM Standards:2D150 Test Methods for AC Loss Characteristics and Permittivity (Dielectric Constant) of Solid Electrical Insulation
8、D2624 Test Methods for Electrical Conductivity of Aviation and Distillate FuelsD4306 Practice for Aviation Fuel Sample Containers for Tests Affected by Trace ContaminationE1 Specification for ASTM Liquid-in-Glass Thermometers3. Terminology3.1 Definitions:3.1.1 picosiemens per metre, nthe unit of ele
9、ctrical conductivity is also called a conductivity unit (CU). A siemen is the SIdefinition of reciprocal ohm sometimes called mho.1pS/m51310212 21 m21 51cu51picomho/m (1)3.1.2 rest conductivity, nthe reciprocal of the resistance of uncharged fuel in the absence of ionic depletion or polarization.It
10、is the electrical conductivity at the initial instant of current measurement after a dc voltage is impressed between electrodes.4. Summary of Test Method4.1 Asample of liquid hydrocarbon is introduced into a clean conductivity cell which is connected in series to a battery voltagesource and a sensit
11、ive dc ammeter. The conductivity, automatically calculated from the observed peak current reading dc voltageand cell constant using Ohms law, appears as a digital value in either a manual or automatic mode of meter operation.1 This test method is under the jurisdiction of ASTM Committee D02 on Petro
12、leum Products and Lubricants and is the direct responsibility of Subcommittee D02.J0.04on Additives and Electrical Properties.Current edition approved Dec. 1, 2012June 15, 2013. Published March 2013July 2013. Originally approved in 1983. Last previous edition approved in 20102012 asD4308D4308 12.10.
13、 DOI: 10.1520/D4308-12.10.1520/D4308-13.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not
14、an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate.
15、 In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*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. United States15. S
16、ignificance and Use5.1 The generation and dissipation of electrostatic charge in fuel due to handling depend largely on the ionic species presentwhich may be characterized by the rest or equilibrium electrical conductivity. The time for static charge to dissipate is inverselyrelated to conductivity.
17、 This test method can supplement Test Method D2624 which is limited to fuels containing static dissipatoradditive.NOTE 1For low-conductivity fluids below 1 pS/m in conductivity, an ac measurement technique is preferable to a dc test method for sensing theelectrical conductivity of bulk fluid. This d
18、c test method can be used at conductivities from 0.1 to 1 pS/m if precautions are observed in cell cleaningand sample handling. A waiting period of 15 min is required after filling the cell before measuring dc conductivities below 1 pS/m. A single-laboratoryprogram was conducted comparing this test
19、method with ac Test Methods D150.36. Apparatus6.1 Conductivity ApparatusComponents of the dc conductivity apparatus are shown in Fig. 1.4,56.1.1 The conductivity cell shown in Fig. 1 consists of an inner electrode and an outer electrode separated by an insulator. Theouter electrode and cap provide a
20、 ground path and electrostatic (Faraday) shield.6.1.2 The electrometer shown in Fig. 1 contains a battery which supplies a voltage to the cell and a bridge circuit which sensesthe flow of current and converts the output signal directly into conductivity units, that is, pS/m. A pushbutton selector al
21、lowsselection of zero reading, calibration, and four range selections.6.1.3 The cell and electrometer are connected by a triaxial cable as shown in Fig. 1.6.2 Thermometer, general purpose type, having a range of 0 to 60C (see Specification E1). Temperature measuring devices thatcover the temperature
22、 range of interest, such as an ASTM 1C thermometer, or liquid-in-glass thermometers, thermocouples, orplatinum resistance thermometers that provide equivalent or better accuracy and precision than ASTM 1C thermometers may beused.3 Supporting data have been filed at ASTM International Headquarters an
23、d may be obtained by requesting Research Report RR:D02-1241.4 The sole source of supply of the apparatus, the KSLACell and Precision Conductivity Meter System, Emcee Model #1154, known to the committee at this time is EmceeElectronics, Inc., 520 Cypress Ave., Venice, FL 34285.5 If you are aware of a
24、lternative suppliers, please provide this information to ASTM International Headquarters. Your comments will receive careful consideration at ameeting of the responsible technical committee,1 which you may attend.FIG. 1 Precision Conductivity MeterD4308 1327. Reagents7.1 Cleaning Solvent, The follow
25、ing may be used:7.1.1 Toluene-Isopropyl Alcohol Mixture(WarningFlammable. Vapor harmful. See Annex A1.1. ) Mix two volumes oftoluene and three volumes of isopropyl alcohol both of reagent grade and distill. Discard the first 20 % and last 5 % fractions.7.2 n-Heptane(WarningFlammable. Harmful if inha
26、led. See Annex A1.2.) Prepare by percolating ASTM reference fuelgrade n-heptane through silica gel5,6 as follows:7.2.1 Activate approximately 2000 g of 100 to 200 mesh silica gel by heating at 180C for 24 h.Allow it to cool in a desiccatorunder nitrogen or in vacuum. Soak approximately 0.5 g of glas
27、s wool5,7 for 24 h in clean n-heptane.7.2.2 Take a tube of borosilicate glass having an inside diameter of 60 to 70 mm, a length 1500 mm, with a conically shapedlower end provided with a glass cock. Place a perforated porcelain disk (diameter 25 mm) in the lower end of the tube and putthe soaked gla
28、ss wool on top of the disk. Fill the tube with the activated silica gel while tapping to achieve homogeneous filling.The silica gel layer will be approximately 1250 mm high. Wrap the column in black paper to exclude light.7.2.3 Percolate n-heptane through the column at a rate of about 2 to 3 L/h. Di
29、scard the first 3 L. Never allow the column to rundry. The silica gel charge is sufficient for the percolation of 1000 L of n-heptane, provided the conductivity of the untreatedn-heptane is below 1 pS/m.NOTE 2If the conductivity of the n-heptane after treatment, measured in accordance with Section 1
30、1 in a thoroughly cleaned cell, is higher than 0.1pS/m, the treatment should be repeated.7.3 Hydrocarbon, for calibration. The dielectric constant must be known to 65 % at the temperature of calibration.88. Sampling8.1 The sample volume should be at least 0.7 L.8.2 Use a clean epoxy-lined can, or a
31、new glass bottle that has been rinsed successively with hot water, distilled water, acetone,and cleaning solvent then flush with dry nitrogen. Use only non-contaminating caps.NOTE 3Test method results are known to be sensitive to trace contamination from sampling containers. For recommended sampling
32、 containers referto Practice D4306.NOTE 4Bottle samples should be tested immediately, since the glass surface tends to absorb from the fuel the conductive substances that the testmethod is intended to measure.8.3 Rinse the container several at least three times with portions of the hydrocarbon liqui
33、d to be sampled. (When testing dieselor aviation turbine fuels JetAorA-1, WarningCombustible. Vapor harmful. SeeAnnex A1.3.) (When testing gasoline, aviationgasoline, or aviation turbine fuel Jet B, WarningExtremely flammable. Harmful if inhaled. Vapors can cause flash fire. SeeAnnex A1.4.) If possi
34、ble, fill the container, let stand, then empty and refill. Avoid taking the sample for test by pouring from thecontainer; pipet instead. The sample should be clean and bright when tested.9. Preparation of Apparatus9.1 Cleaning the CellThe cleaning procedure to be used depends on the estimated conduc
35、tivity of the sample to be tested.9.1.1 For samples that are expected to exhibit conductivities below 1 pS/m, the KSLAcell should be completely disassembled,the parts cleaned and the cell reassembled using protective gloves.9.1.1.1 Dismantle the cell by removing the loose battery cap, the outer elec
36、trode electrical connector and the bottom screw-oncap. Press the inner electrode towards the bottom of the outer electrode and remove the inner electrode TFE-fluorocarbon insulatorassembly.9.1.1.2 Each part of the cell should be rinsed thoroughly five times with cleaning solvent followed by rinsing
37、with treatedn-heptane. The parts should be dried with a stream of nitrogen gas.9.1.1.3 After reassembly, the cell should be rinsed with treated n-heptane.9.1.1.4 After cleaning, check the cleanliness of the cell by measuring the conductivity of treated n-heptane in accordance withSection 11. The cor
38、rected value should be lower than 0.05 pS/m.9.1.2 For samples that are expected to exhibit conductivities above 1 pS/m, the KSLAcell still assembled should be rinsed fivetimes with cleaning solvent, followed by rinsing with treated n-heptane. The cell should be dried with a stream of nitrogen gas.9.
39、1.2.1 After cleaning, check the cleanliness of the cell by measuring the conductivity of treated n-heptane in accordance withSection 11. The corrected value should be lower than 0.1 pS/m.9.2 Cleaning of Auxiliary Equipment:9.2.1 Pipets used to transfer samples should be rinsed inside and outside wit
40、h cleaning solvent using a non-contaminatingsqueeze bottle, then blown dry with clean, dry nitrogen. Thermometers should be similarly rinsed and maintained.6 The sole source of supply known to the committee at this time is Code 923, from W. R. Grace or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).D4308 137
