1、Designation: D 1698 03Standard Test Method forSediments and Soluble Sludge in Service-Aged InsulatingOils1This standard is issued under the fixed designation D 1698; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last
2、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 This test method covers the determination of sedimentand soluble sludge in service-aged insulating oils of petroleumorigin
3、. Also, provision is made for determining organic andinorganic content of the sediment. The method is intendedprimarily for oils of comparatively low viscosity; for example5.7 to 13.0 cSt (mm2/s) at 40C (104F). Suitability for highviscosity oils have not been determined.1.2 This standard may involve
4、 hazardous materials, opera-tions, and equipment. This standard does not purport toaddress all of the safety concerns, if any, associated with itsuse. It is the responsibility of the user of this standard toestablish appropriate safety and health practices and deter-mine the applicability of regulat
5、ory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:D 923 Practices for Sampling Electrical Insulating Liquids2D 2440 Test Method for Oxidation Stability of MineralInsulating Oil23. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 inorganic sedimentthat portion
6、of the total sedimentwhich remains after ignition at 500C.3.1.2 organic sedimentthat portion of the total sedimentwhich is lost during ignition at 500C.3.1.3 sedimentany solid substance or substances that areinsoluble in the oil under test at ordinary room temperatures,and that can be separated by c
7、entrifuging under certainprescribed conditions.3.1.4 soluble sludgeoil deterioration products or contami-nants, or both, which become insoluble upon dilution withn-pentane under prescribed conditions.4. Summary of Test Method4.1 A sample portion is centrifuged to separate sedimentfrom the oil. The u
8、pper, sediment-free portion is decanted andretained for determination of soluble sludge. The sediment isdislodged and filtered through a filtering crucible. After dryingand weighing to obtain total sediment the crucible is ignited at500C and reweighed. Loss in weight is organic and theremainder is i
9、norganic content of sediment. Soluble sludge isdetermined on the sediment-free portion by dilution withn-pentane to precipitate n-pentane insolubles, and filtrationthrough a filtering crucible or 0.45 m filter membrane.5. Significance and Use5.1 Sediment in insulating oil may deposit on transformerp
10、arts and interfere with heat transfer and may choke oil ducts;thus hindering oil circulation and heat dissipation. Inorganicsediment usually indicates contamination of some type andorganic sediment indicates either deterioration of the oil orcontamination.5.2 Soluble sludge indicates deterioration o
11、f the oil, pres-ence of contaminants, or both. It serves as a warning thatformation of sediment may be imminent.5.3 The determination of sediment and soluble sludge in aused insulating oil assists in deciding whether the oil maycontinue to be used in its existing condition or should bereplaced, recl
12、aimed, or reconditioned.6. Apparatus6.1 Centrifuge Tube, 30-mL capacity, preferably with roundor elliptical bottom to facilitate removal of sediment. Pear-shaped tubes are not recommended.6.2 Centrifuge, capable of whirling two or more filledcentrifuge tubes at a speed which can be controlled to giv
13、e arelative centrifugal force (rcf) between 600 and 700 at the tipsof the tubes. The revolving head, trunnion rings, and trunnioncups, including the rubber cushion, shall be soundly con-structed to withstand the maximum centrifugal force capable ofbeing delivered by the power source. The trunnion cu
14、ps andcushions shall firmly support the tubes when the centrifuge isin motion. The centrifuge shall be enclosed by a metal shield or1This test method is under the jurisdiction of ASTM Committee D27 onElectrical Insulating Liquids and Gases and is the direct responsibility of Subcom-mittee D27.07 on
15、Physical Tests.Current edition approved May 10, 2003. Published July 2003. Originallyapproved in 1959. Last previous edition approved in 1997 as D 1698 97.2Annual Book of ASTM Standards, Vol 10.03.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, Un
16、ited States.case strong enough to eliminate danger if any breakage occurs.Calculate the speed of the rotating head by means of thefollowing equation:rpm 5 265 =rcf/dwhere:rcf = relative centrifugal force, andd = diameter of swing, in., measured between tips ofopposite tubes when in rotating position
17、,or:d = diameter of swing cm/2.54, measured between tips ofopposite tubes when in rotating position.6.3 Electric Muffle Furnace, capable of maintaining a tem-perature of 500 6 15C.6.4 Explosion-Proof Oven, capable of maintaining a tem-perature of 105 6 3C.6.5 Filtering CrucibleGlass filter crucible
18、having a maxi-mum diameter of the pores of between 5 and 15 m asdetermined in accordance with the Appendix in Test MethodD 2440.6.6 Filter MembraneA 47 mm diameter, 0.45 m poresize cellulose ester type filter.7. Reagents and Materials7.1 AcetoneReagent grade.7.2 Chloroform, Reagent grade.7.3 Normal
19、Pentane, Reagent grade.8. Sampling8.1 Obtain the sample of used oil in accordance withPractices D 923. In addition, protect the sample from light.9. Procedure for Total Sediment9.1 Clean the glass filtering crucible and dry in an air ovenat 105 to 110C until it has reached constant weight. Dry filte
20、rmembranes in an oven at 105C for 15 min. Cool and store thecrucible in a desiccator and, when needed, weigh to the nearest0.0001 g.9.2 Thoroughly agitate the sample of used oil to produce ahomogenous mixture, and place 25 g of the well-mixed oil ineach of two centrifuge tubes. Balance the two centr
21、ifuge tubesand their respective trunnion cups, place them on oppositesides of the centrifuge head, and centrifuge for 30 min at arelative centrifugal force between 600 and 700 at the tips of thetubes.9.3 Carefully decant the supernatant liquid without dispers-ing the precipitated sediment, saving th
22、e decanted portion fordetermination of soluble sludge. Dislodge and wash the sedi-ment from the centrifuge tube into a tared, filtering crucible,using n-pentane as the washing agent. Make certain that anysediment adhering to instruments used in cleaning the tube isalso transferred to the filtering c
23、rucible. A filter membrane maybe used instead of the filtering crucible if only total sediment isto be determined.9.4 Wash the sediment in the filtering crucible thoroughlywith n-pentane to remove all traces of oil. Normally, threewashes of 25-mL portions each are sufficient. A drop of thefinal n-pe
24、ntane washing should show no oil stain on a filterpaper.9.5 Dry the sediment in the filtering crucible by suction, andplace in an oven at 105C for drying to constant weight. Coolin a desiccator and weigh to the nearest 0.0001 g.10. Procedure for Organic and Inorganic Sediment10.1 Wash the sediment i
25、n the filtering crucible with chlo-roform or acetone until it is free of chloroform or acetone-soluble material (see Note). Three washes of 25-mL portionseach are usually sufficient.10.2 Dry the sediment by suction and ignite in the cruciblein an electric muffle furnace at 500C for 1 h, cool in ades
26、iccator, and weigh to the nearest 0.0001 g.NOTE 1If so desired, the chloroform or acetone washes can becombined and retained for further chemical analysis.11. Procedure for Soluble Sludge11.1 Place the crucible in an oven and dry at 105 to 110Cto constant weight or dry a 0.45 m filter membrane filte
27、r in anoven at 105C for 15 min. Cool in a desiccator and weigh to thenearest 0.0001 g.11.2 Transfer 20 g of the decanted portion of the centrifugedoil to a 600-mL high-form beaker with pouring spout. Add 200mL of n-pentane, mix thoroughly, and place a cover glass oralumninum foil on the beaker. Plac
28、e the covered beaker in anarea protected from light and drafts, and let it stand overnight,or approximately 16 h, at ordinary room temperature.11.3 Filter the oil-pentane solution through the tared filter-ing crucible or filter membrane, making certain that all solidmaterial is transferred to the cr
29、ucible or filter membrane bythoroughly cleaning and washing the beaker with n-pentane.11.4 Wash the soluble sludge in the filtering crucible thor-oughly with n-pentane to remove all traces of oil. Normallythree washes of 25-mL portions each are sufficient.11.5 Dry the soluble sludge in the filtering
30、 crucible or filtermembrane by suction and place in an oven at 105C for dryingto constant weight. Cool in a desiccator and weigh to thenearest 0.0001 g.12. Calculation12.1 Calculate the percentage of total sediment in the usedoil as follows:Total sediment, % 5 100/25B 2 A! or 4B 2 A!where:A = weight
31、 of tared ignited filtering crucible, andB = weight of oven-dried sediment and filtering crucible, g.12.2 Calculate the percentage of organic sediment in theused oil as follows:Organic sediment, % 5 100/25B 2 C! or 4B 2 C!where:D 1698 032B = weight of oven-dried sediment and filtering crucible, g,an
32、dC = weight of ignited sediment and filtering crucible, g.12.3 Calculate the percentage of inorganic sediment in theused oil as follows:Inorganic sediment, % 5 100/25C 2 A! or 4C 2 A!where:A = weight of tared, ignited filtering crucible, g, andC = weight of ignited sediment and filtering crucible, g
33、.12.4 Calculate the percentage of soluble sludge in the usedoil as follows:Soluble sludge, % 5 100/20E 2 D! or 5E 2 D!where:D = weight of tared, oven-dried filtering crucible or filtermembrane, g, andE = weight of soluble sludge and filtering crucible or filtermembrane, g.13. Report13.1 Report the f
34、ollowing information and data, recordingpercentages below 1 % to three digits and percentages of 1 %or more to two digits:13.1.1 Date on which the sample of used oil was removedfrom service,13.1.2 Date on which the sample was tested,13.1.3 Total sediment, in %,13.1.4 Organic sediment, in %,13.1.5 In
35、organic sediment, in %, and13.1.6 Soluble sludge, in %.14. Precision and Bias14.1 RepeatabilityTwo distinct measurements of solublesludge, made in one laboratory on different days, should differby no more than 0.013 % soluble sludge, 95 % of the time.14.2 ReproducibilityTwo laboratories, each report
36、ing theaverage of two distinct measurements of soluble sludge, shoulddiffer by no more than 0.044 % soluble sludge, 95 % of thetime.14.3 BiasThe foregoing statements are restricted to themeasurement of soluble sludge, which may be assumed to beuniformly dispersed through the oil sample. Since solid
37、sedi-ment is not uniformly dispersed but occurs in discrete particles,no meaningful statement as to bias can be made.15. Keywords15.1 insulating oils; oils; sediments; sludge; soluble-sludgeASTM International takes no position respecting the validity of any patent rights asserted in connection with
38、any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent 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 technic
39、al committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration
40、 at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing 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 Harbo
41、r 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 1698 033
