1、Designation: D 2112 01a (Reapproved 2007)Standard Test Method forOxidation Stability of Inhibited Mineral Insulating Oil byPressure Vessel1This standard is issued under the fixed designation D 2112; the number immediately following the designation indicates the year oforiginal adoption or, in the ca
2、se 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.This standard has been approved for use by agencies of the Department of Defense.1. Scope1.1 This tes
3、t method covers and is intended as a rapidmethod for the evaluation of the oxidation stability of newmineral insulating oils containing a synthetic oxidation inhibi-tor. This test is considered of value in checking the oxidationstability of new mineral insulating oils containing 2,6-ditertiary-butyl
4、 para-cresol or 2,6-ditertiary-butyl phenol, orboth, in order to control the continuity of this property fromshipment to shipment. The applicability of this procedure foruse with inhibited mineral insulating oils of more than 12 cStat 40C (approximately 65 SUS at 100F) has not beenestablished.1.2 Th
5、is 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 establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. (See warning in6.7.)
6、NOTE 1A modification of this test method, which uses the sameprocedure and apparatus but a higher (150C) bath temperature, has beenpublished as Test Method D 2272.2. Referenced Documents2.1 ASTM Standards:2B1 Specification for Hard-Drawn Copper WireD 2272 Test Method for Oxidation Stability of Steam
7、 Tur-bine Oils by Rotating Pressure VesselE1 Specification for ASTM Liquid-in-Glass Thermometers3. Summary of Test Method3.1 The test specimen is agitated by rotating axially at 100rpm at an angle of 30 from the horizontal, under an initialoxygen pressure of 90 psi (620 kPa), in a stainless steel or
8、copper vessel (for rapid temperature equilibrium), with a glasstest specimen container and copper catalyst coil, in the pres-ence of water, at a bath temperature of 140C. The time for anoil to react with a given volume of oxygen is measured;completion of the test is indicated by a specific drop inpr
9、essure.4. Signifance and Use4.1 This is a control test of oxidation stability of new,inhibited mineral insulating oils for determining the inductionperiod of oxidation inhibitors under prescribed acceleratedaging conditions. There is no proven correlation between oilperformance in this test and perf
10、ormance in service. However,the test method may be used to check the continuity ofoxidation stability of production oils.5. Apparatus5.1 Oxidation Vessel Glass test specimen container withcover and catalyst coil, pressure gage, thermometer, test bath,and accessories as described in Annex A1. The ass
11、embledapparatus is shown in Fig. 1, and its design shown schemati-cally in Fig. 2.6. Reagents and Materials6.1 Purity of ReagentsUse reagent grade chemicals in alltests. Unless otherwise indicated, all reagents shall conform tothe specifications of the Committee on Analytical Reagents ofthe American
12、 Chemical Society, where such specifications areavailable.36.2 Hydrochloric Acid, 10 vol %.6.3 Silicon Carbide Abrasive Cloth, 100-grit with clothbacking.6.4 Acetone, cp.6.5 2-Propanol, 99 vol %, refined.6.6 Liquid Detergent.1This test method is under the jurisdiction of ASTM Committee D27 onElectri
13、cal Insulating Liquids and Gases and is the direct responsibility of Subcom-mittee D27.06 on Chemical Test.Current edition approved July 15, 2007. Published August 2007. Originallyapproved in 1962. Last previous edition approved in 2001 as D 211201a.2For referenced ASTM standards, visit the ASTM web
14、site, 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.3Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For sug
15、gestions on the testing of reagents notlisted by the American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.1Copyright ASTM Internationa
16、l, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.6.7 Oxygen, 99.5 %, with pressure regulation above 90 psi(620 kPa). (WarningOxygen vigorously accelerates com-bustion).6.8 Potassium Hydroxide, Alcohol Solution (1 mass %)Dissolve 7.93 g of potassium hydroxide (KO
17、H) pellets in 1 Lof 99 % refined 2-propanol.6.9 Silicone Stopcock Grease.6.10 Wire Catalyst AWG No. 14 (0.0641-in. (1.628-mm)diameter) electrolytic copper wire 99.9 % purity, conformingto Specification B1. Soft-drawn copper wire of an equivalentgrade may also be used.7. Hazards7.1 Consult Material S
18、afety Data Sheets for all materialsused in this test method.8. Preparation of Apparatus8.1 Catalyst PreparationImmediately before use, polishthe copper wire with silicon carbide abrasive cloth and wipefree from abrasives with a clean dry cloth. Wind approximately3 m of the wire into a coil having an
19、 outside diameter of 44 to48 mm and stretched to a height of 40 to 42 mm. Clean the coilthoroughly with acetone and allow it to air-dry. Immediatelyafter air drying, insert the coil with a twisting motion into theglass test specimen container. Handle the coil only with cleantongs to avoid contaminat
20、ion. Weigh the coil and the containerto the nearest 0.1 g and record the weight. Prepare a new coilfor each test specimen.8.2 Alternative Method of Catalyst PreparationWind ap-proximately3mofcopper wire into a coil of the dimensionsspecified in 8.1, and add to the glass container. Weigh the coiland
21、container to the nearest 0.1 g and record the weight. Washthe coil by filling the container above the level of the coil with10 % hydrochloric acid by volume for 30 s. Discard the acidand rinse the coils three times with tap water followed by threetimes with distilled water. Reweigh the coil and cont
22、ainer anddetermine by difference the water retained in the system. Thecoils are now ready for use. This procedure has been found tobe acceptable for treatment of commercially available, pre-packaged, preformed coils that meet the requirement describedin this test method. Use a new coil for each test
23、 specimen.8.3 Cleaning of Vessel Wash the vessel body, lid, andinside of vessel stem with hot detergent solution and withwater. Rinse inside of stem with 2propanol and blow dry withclean dry air. An alternative cleaning solution is the use of a50/50 volumetric blend of methanol and acetone; it has b
24、eenfound to be effective in cleaning sludge from the vessel. If thevessel body, lid, or inside of stem smells sour after simplecleaning, wash with alcoholic KOH solution and repeat asbefore (see Note 2).NOTE 2Insufficient cleaning of the vessel may adversely affect testresults.9. Procedure9.1 Chargi
25、ngWeigh 50 6 0.5 g of oil sample into thecontainer, add 5 mL of distilled water, and cover with a 2-in.(51-mm) watch glass or a 214-in. (57.2-mm) PTFE disk withone or four holes and retaining spring. If rinse water is presentin the container, compensate for it by using less added waterbased on the w
26、ater retention determined in 8.3.Add5mLofdistilled water to the vessel and slide the test specimencontainer and cover lid into the vessel body (see Note 3).Applya thin coating of silicone stopcock grease to the O-ring vesselseal located in the gasket groove of the vessel lid to providelubrication, a
27、nd insert the lid into the vessel body. Place thevessel cap over the vessel stem, and tighten by hand. Cover thethreads of the gage-nipple with a thin coating of stopcockgrease or TFE-fluorocarbon, or both, and screw the gage intothe top-center tap of the vessel stem. Flush the vessel twicewith oxyg
28、en supplied to the vessel at 90 psi (620 kPa) andrelease to the atmosphere. Adjust the regulating valve on theoxygen supply tank to 90 psi at a room temperature of 25C(77F). For each 2.8C (5.1F) above or below this tempera-ture, add or subtract 1 psi (7 kPa) unit to attain the requiredinitial pressu
29、re. Fill the vessel to this required pressure andclose the inlet valve securely by hand. If desired, test the vesselfor leaks by immersion in water (see Note 4). Prepare aduplicate test specimen in exactly the same way.NOTE 3The water between the vessel well and the test specimencontainer aids heat
30、transfer.NOTE 4If the vessel was immersed in water to check for leaks, dry theoutside of the wet vessel by any convenient means such as an air blast ora towel. Such drying is advisable to prevent subsequent introduction offree water into the hot oil bath, which would cause sputtering.9.2 OxidationBr
31、ing the heating bath to the test tempera-ture of 140C while the stirrer is in operation. Insert the vesselsinto the rotating carriages and note the time. If an auxiliaryheater is used, keep it on for the first 5 min of the run and thenturn it off (see Note 5). Allow the bath temperature to level out
32、at the test temperature; this must occur within 10 min after thevessels are inserted. Maintain the test temperature within60.1C (see Note 6).NOTE 5The time for the bath to reach the operating temperature afterinsertion of the vessels may differ for different apparatus assemblies andshould be observe
33、d for each unit. The objective is to find a set ofconditions that does not permit a drop of more than 2C after insertion ofthe vessels and allows the vessel pressure to reach a plateau within 15 minas shown in Curve A of Fig. 3.FIG. 1 Rotating Vessel Oxidation Test ApparatusD 2112 01a (2007)2NOTE 6M
34、aintaining the correct temperature within the specificationlimits of 60.1C during the entire test run is the most important singlefactor ensuring good repeatability and reproducibility of test results.9.3 Keep the vessels completely submerged and maintainrotation continuously and uniformly throughou
35、t the test. Astandard rotational speed of 100 6 5 rpm is required; anyappreciable variations in this speed could cause erratic results.If a dial gage is used, take readings every 5 min.9.4 The test is complete after the pressure drops more than25 psi (172 kPa) below the maximum pressure. The 25-psip
36、ressure drop usually, but not always, coincides with aninduction-type “period of rapid pressure drop.” When it doesnot, the operator should question whether a valid experimenthas been produced.NOTE 7A typical experiment is shown in Fig. 3 as Curve A. Themaximum pressure expected to be reached within
37、 30 min; a pressureplateau is established and an induction-type pressure drop is observed.Curve B, in which there is a gradual decrease in pressure before theinduction break is recorded, is more difficult to evaluate. The gradualdecrease in pressure could be due to a vessel leak; however, someFIG. 2
38、 Schematic Drawing of Rotary VesselFIG. 3 Pressure Versus Time Plot of Two Rotary Vessel Oxidation Test RunsD 2112 01a (2007)3synthetic fluids will generate this type of curve. If a leak is suspected,repeat the test in a different vessel. If the same type of curve is derivedwhen the test is repeated
39、, the experiment is likely valid.9.5 After termination of the test, remove the vessels fromthe oil bath, dip briefly into and swirl around in a bath of lightmineral oil or detergent and water to wash off the adhering bathoil. Rinse off the vessels with hot water, then immerse in coldwater to bring t
40、hem quickly to room temperature. Allow thevessel to fully cool before bleeding off excess oxygen pressureand opening the vessel.NOTE 8A hazardous situation can arise when excess oxygen is bledoff immediately upon removal of the vessel from the bath since it may beaccompanied by hot oil and steam. (S
41、ee 6.7).10. Interpretation of Results10.1 Observe a plot of the recorded pressure versus time andestablish the plateau pressure (see Note 7).Also record the timeat the point on the falling part of the curve where the pressureis 25 psi (172 kPa) less than the established plateau pressure.Plateau pres
42、sures in duplicate tests should not differ by morethan 5 psi (35 kPa).10.2 The vessel life of the test specimen is the time inminutes from the start of the test to a 25-psi pressure drop fromthe level of the established plateau.11. Report11.1 Report the time as the average of two duplicatedeterminat
43、ions and the difference of the individual determina-tions. The recipient of the report can then be reassured that thedetermination is not suspect, as specified in 12.1.12. Precision and Bias12.1 The following criteria should be used for judging theacceptability of results (95 % probability):12.1.1 R
44、epeatabilityDuplicate determinations by thesame operator should not be considered suspect unless theydiffer by more than 23 min. If the two results differ by morethan the specified value, another set of duplicate tests should beperformed.12.1.2 ReproducibilityResults submitted by each of twolaborato
45、ries based on the average of two determinations in eachlaboratory should not be considered suspect unless they differby more than 43 min.12.2 No justifiable statement can be made on the bias of theprocedure in this test method since there is no acceptedreference material suitable for determining oxi
46、dation stability.13. Keywords13.1 electrical; inhibitor; insulating oil; mineral oil; oxida-tion stability; pressure vessel; rotating vessel; transformer oilANNEX(Mandatory Information)A1. ROTATING VESSEL OXIDATION TEST APPARATUSA1.1 Oxidation VesselA1.1.1 Construct the oxidation vessel,4with lid, c
47、ap, andstem, as shown in Fig. A1.1.A1.1.2 Machine the vessel body and lid from a 3-in.(76-mm) solid copper rod for maximum rate of heat transfer.Give the interior surface a smooth finish to facilitate cleaning.Heavily chrome plate the vessel body and lid.Alternatively, thevessel body and cap may be
48、constructed of 18-8 or 321S12/321S20 Part 1 (BSI) stainless steel to ensure a proper rate ofheat transfer.A1.1.3 Construct the vessel stem of stainless steel, equippedwith an inside diameter of14 in. (6.35 mm) and equip with a14-in. needle valve.A1.1.4 Make the vessel cap (or closure ring) of plated
49、 steel.A1.1.5 The vessel shall withstand a working pressure of 500psi (3.4 MPa) at 150C.A1.1.6 O-ring gaskets, TFE-fluorocarbon resin reinforcedsilicone, 2 in. (50.8 mm) in inside diameter by 238 in. (60.3mm) in outside diameter, or alternatively Buna-N gaskets withthe same dimensions.A1.2 Glass Sample ContainerA1.2.1 Construct the glass test specimen container, 175-mLcapacity, with copper catalyst coil, of borosilicate glass asshown in Fig. A1.2.A1.2.2 Cover the top of the test specimen container with a2-in. (50.8-mm) diameter watch glass. Fir
