1、Designation: D 1807 00 (Reapproved 2005)Standard Test Methods forRefractive Index and Specific Optical Dispersion ofElectrical Insulating Liquids1This standard is issued under the fixed designation D 1807; the number immediately following the designation indicates the year oforiginal adoption or, in
2、 the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 These test methods cover the determination of therefractive index and the specific
3、 optical dispersion of electricalinsulating liquids such as are used in capacitors, transformers,circuit breakers, and oil-filled cables.1.2 Two test methods are described, a routine method and amore precise referee method. Both methods are applicable totransparent, light-colored, insulating liquids
4、.1.2.1 The routine method is used to determine refractiveindex and specific optical dispersion as described in these testmethods.1.2.2 The referee method is used when a test of highaccuracy is desired. These methods are described in TestMethod D 1218. Specific optical dispersion is calculated bydivi
5、ding the refractive dispersion value determined in TestMethod D 1218 by the relative density (specific gravity) (seeTest Method D 1298) of the liquid under test.1.3 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.4 This stand
6、ard 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 establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 AS
7、TM Standards:2D 1218 Test Method for Refractive Index and RefractiveDispersion of Hydrocarbon LiquidsD 1298 Test Method for Density, Relative Density (SpecificGravity), or API Gravity of Crude Petroleum and LiquidPetroleum Products by Hydrometer Method3. Terminology3.1 Definitions:3.1.1 refractive i
8、ndex, nthe ratio of the velocity of light inair to its velocity in the substance under test.3.1.2 relative density (specific gravity), nthe ratio of themass of a given volume of liquid at 15C (60F) to mass of anequal volume of pure water at the same temperature.3.1.3 specific optical dispersion, nth
9、e difference betweenthe refractive indexes of light of two different wavelengths,both indexes measured at the same temperature, and divided bythe relative density (specific gravity), also measured at the testtemperature.4. Significance and Use4.1 Refractive IndexThe refractive index of an insulating
10、liquid varies with its composition and with the nature andamount of contaminants held in solution. Changes of refractiveindex with time and service may form a basis for estimatingany change in composition or the degree of containmentacquired in service. For electrical insulating mineral oils, thewav
11、elength of 5893 Afor the spectral line of sodium iscommonly used. The test temperature is 25C.4.2 Specific Optical DispersionSpecific optical dispersionserves as a quick index to the amount of unsaturated com-pounds present in an oil. Dispersion values for paraffinic andnaphthenic compounds are near
12、ly the same and are essentiallyindependent of molecular weight and structural differences.Values above 97 bear a direct relationship to the amount ofaromatic compounds present in insulating oil. For convenience,the specific dispersion value is multiplied by 104. For electri-cal insulating mineral oi
13、ls, the wavelengths of 6563 and 48611These test methods are under the jurisdiction of ASTM Committee D27 onElectrical Insulating Liquids and Gases and are the direct responsibility ofSubcommittee D27.07 on Physical Tests.Current edition approved Oct. 1, 2005. Published November 2005. Originallyappro
14、ved in 1960. Last previous edition approved in 2000 as D 1807 00.2For referenced ASTM standards, 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 webs
15、ite.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.Acorresponding to the spectral lines of hydrogen are com-monly used. Alternatively, the wavelengths of 6678 and 5016Acorresponding to the spectral lines of helium may be used.5. App
16、aratus5.1 RefractometerThe refractometer to be used in theroutine method shall have an index range of approximately1.33 to 1.5 and be readable to 60.0002 units. The refractome-ter used in the referee method is described in Test MethodD 1218.5.2 Light SourceA suitable incandescent illuminator shallbe
17、 used as a light source for determinations made by theroutine method; suitable light sources for the referee methodare described in Test Method D 1218.5.3 ThermostatA thermostat capable of supplying waterto the jacketed prisms of the refractometer shall be capable ofmaintaining a temperature constan
18、t to within 60.1C.6. Procedure for Routine Method6.1 Periodically check the adjustment of the refractometerwith the reference standard supplied with the instrument.6.2 Clean the instrument in accordance with the instructionsfurnished by the apparatus manufacturer before testing eachspecimen. If no s
19、pecial instructions are provided, clean theprisms with a swab of surgical grade absorbent cotton saturatedwith a suitable solvent such as toluene. Do not dry the prismfaces by rubbing with dry cotton. Allow 4 to 5 min fortemperature equilibration before applying the test specimen tothe prism.6.3 Adj
20、ust the bath thermostat to 25.0C, reading thistemperature on the refractometer thermometer on the dischargeside. Continue the flow of water long enough before testing toensure that a constant temperature has been reached. If only thespecific optical dispersion is desired, the measurements may bemade
21、 at room temperature without use of a temperature-controlled bath.6.4 Apply the test specimen to the surface of the refractingprism or to the capillary opening with a small pipet or medicinedropper.6.5 Read the refractive index to three decimal places andestimate the fourth place.6.6 Test additional
22、 specimens until three readings that donot show a spread of more than two units in the fourth decimalplace have been secured. Record the refractive index as theaverage of these readings to four decimal places.6.7 Read the compensator dial in two positions and averagethe values.6.8 Calculate the spec
23、ific optical dispersion by first comput-ing the refractive dispersion. Use the nomograph or tableprovided with the instrument. Divide the dispersion value bythe relative density (specific gravity) of the oil corrected to thetemperature at which the dispersion readings were made.Determine the relativ
24、e density (specific gravity) in accordancewith Test Method D 1298.7. Procedure for Referee Method7.1 Determine the refractive index and refractive dispersionin accordance with Test Method D 1218.7.2 Calculate the specific optical dispersion by dividing thedispersion value by the relative density (sp
25、ecific gravity) of theoil. Correct to the temperature at which the dispersion readingswere made. Determine the specific gravity in accordance withTest Method D 1298.8. Report8.1 Report the following:8.1.1 A description of the sample, such as fluid type, samplelocation, physical appearance, etc.8.1.2
26、 Refractive index, reported to the fourth decimal place,and the temperature at which the test was made.8.1.3 Multiply the specific optical dispersion value by 104,and for the routine method report the result as a whole numberof two or three digits. For the referee method, report the resultsas a thre
27、e or four-digit number, the last digit occupying the firstdecimal place.8.1.4 The spectral line, or lines, used in the measurements.9. Precision and Bias9.1 Precision:9.1.1 The precision of the routine method for measuringrefractive index and specific optical dispersion of this testmethod is being d
28、etermined.9.1.2 The precision of the referee method for measuringrefractive index and specific optical dispersion is essentiallyspecified in Test Method D 1218.9.2 Bias:9.2.1 No information can be presented on the bias of theroutine procedure in this test method for measuring refractiveindex and spe
29、cific optical dispersion because no materialhaving an accepted reference value is available.9.2.2 The bias of the referee procedure for measuringrefractive index and specific optical dispersion is essentiallyspecified in Test Method D 1218.10. Keywords10.1 insulating liquids; refractive index; refra
30、ctometer; spe-cific optical dispersionD 1807 00 (2005)2ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent
31、rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either
32、for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hear
33、ing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).D 1807 00 (2005)3
