1、Designation: D4871 11 (Reapproved 2016)Standard Guide forUniversal Oxidation/Thermal Stability Test Apparatus1This standard is issued under the fixed designation D4871; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of la
2、st revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This guide covers an apparatus used to measure theoxidation or thermal stability of liquids by subjecting them totempera
3、tures in the range from 50 C to 375 C in the presenceof air, oxygen, nitrogen, or other gases at flow rates of 1.5 L hto 13 L h, or in the absence of gas flow. Stability may bemeasured in the presence or absence of water or soluble orinsoluble catalysts. Gases evolved may be allowed to escape,conden
4、sed and collected, or condensed and returned to the testcell.1.2 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is the
5、responsibility 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 ASTM Standards:2D91 Test Method for Precipitation Number of LubricatingOilsD156 Test Method for Saybolt
6、 Color of Petroleum Products(Saybolt Chromometer Method)D445 Test Method for Kinematic Viscosity of Transparentand Opaque Liquids (and Calculation of Dynamic Viscos-ity)D664 Test Method for Acid Number of Petroleum Productsby Potentiometric TitrationD974 Test Method for Acid and Base Number by Color
7、-Indicator TitrationD1500 Test Method for ASTM Color of Petroleum Products(ASTM Color Scale)D3339 Test Method for Acid Number of Petroleum Productsby Semi-Micro Color Indicator TitrationD5763 Test Method for Oxidation and Thermal StabilityCharacteristics of Gear Oils Using Universal GlasswareD5770 T
8、est Method for Semiquantitative Micro Determina-tion of Acid Number of Lubricating Oils During Oxida-tion TestingD5846 Test Method for Universal Oxidation Test for Hy-draulic and Turbine Oils Using the Universal OxidationTest ApparatusD6514 Test Method for High Temperature Universal Oxida-tion Test
9、for Turbine Oils3. Summary of Guide3.1 An apparatus is described in which a sample of testfluid, typically from 100 mL or 100 g, is subjected to thermalor oxidative degradation or both. Insoluble or soluble catalystmay be added. Gas may be bubbled through the liquid toprovide agitation or to promote
10、 oxidation or both. Water orwater vapor may be added. At the end of the test or at intervalsthroughout the test, the liquid is monitored for change inneutralization number, viscosity, weight loss, formation ofsludge, or for other parameters. The corrosivity of the fluidtoward any catalyst metals can
11、 be determined from theappearance and weight change of the metal test specimens, ifpresent, or by monitoring the oil and any sludge or water formetal content. The test is terminated after a fixed time periodor when a selected parameter reaches a condemning value.NOTE 1The volume of liquid at test te
12、mperature should be sufficientto cover the catalysts and should not extend beyond the heated portion ofthe bath.4. Significance and Use4.1 This standard describes an apparatus that provides theversatility required to conduct oxidation or thermal stabilitytests on liquids using a wide variety of test
13、 conditions. It issufficiently flexible so that new test conditions can be chosen inresponse to the changing demands of the marketplace.4.2 Procedures using this apparatus are described in thefollowing ASTM standard test methods: D5763, D5846, andD6514. Other procedures may be in use, but they have
14、not beendeveloped as ASTM standard test methods.1This guide is under the jurisdiction of ASTM Committee D02 on PetroleumProducts, Liquid Fuels, and Lubricants and is the direct responsibility of Subcom-mittee D02.09.0D on Oxidation of Lubricants.Current edition approved Oct. 1, 2016. Published Novem
15、ber 2016. Originallyapproved in 1988. Last previous edition approved in 2011 as D4871 11. DOI:10.1520/D4871-11R16.2For 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 th
16、e standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States15. Apparatus5.1 Heating Block, as shown at the lower right in Fig. 1,toprovide a controlled constant temperature for conducting tests
17、.5.1.1 Test cells are maintained at constant elevated tempera-ture by means of a heated aluminum block which surroundseach test cell.5.1.2 Holes in the aluminum block to accommodate the testcells shall provide 1.0 mm max clearance for 38 mm outsidediameter glass tubes. The glass test cells shall fit
18、 into the blockto a depth of 225 mm 6 5 mm.NOTE 2The original test blocks were made with spaces for ten testcells. Blocks with different number of holes are acceptable if otherrequirements are met.5.1.3 The heating system shall be geometrically and ther-mally balanced. For thermal balance, sizes and
19、 locations of theheaters are proportioned against heat losses.5.1.4 The block is cylindrical and constructed from forgedaluminum. The block has a minimum thickness of 38 mm ofinsulation on all sides, top and bottom. An insulation ofthermally efficient ceramic fiber material is suggested.5.1.5 The ex
20、terior jacket, sides and top are stainless steel orequivalent.5.1.6 The block is equipped with a well for a temperaturemeasuring device and a thermometer.5.2 Temperature Control System, as shown at lower left inFig. 1, to maintain the heating block at a set temperature.5.2.1 The temperature controll
21、er shall be capable of main-taining the block temperature within 60.5 C of the desiredtest temperature for the duration of the test. The preferredcontroller shall have proportional and integral control modes,and a heater malfunction alarm.5.2.2 The range for operation is from at least 50 C to375 C.
22、(WarningAn adjustable deviation alarm that auto-matically shuts down the system if temperature varies outsidepreset limits is desirable as a safety feature and to avoidFIG. 1 Universal Oxidation Test ApparatusD4871 11 (2016)2erroneous test results. A separate adjustable high temperaturemonitor and s
23、hutoff is desirable as a safety device.)5.2.3 Temperature control and uniformity is the most im-portant parameter affecting test result precision. Therefore, theheating system design is critical. Temperature from hole-to-hole and at all sides of each hole in the block shall be uniformwithin the 0.5
24、C tolerance of the total system.5.3 Gas Flow Control System, as shown in Fig. 1, to provideair or other gases to each test cell.5.3.1 A gas flow controller is required for each test cell, toprovide air or other desired gases. (WarningIf reactive gasesare to be used in the test procedure, all fitting
25、s in the gascontrol system must be compatible with these gases.)5.3.2 The standard gas flow range shall be from 1.5 L h to13 L h. Flowmeters shall have a scale length sufficiently longto permit accurate reading and control to within 65 % of fullscale. Floats and tubes may be interchangeable for alte
26、rnate gasflow ranges.5.3.3 The system shall have a pressure regulator to provideconstant inlet pressure and 10 flow indicators with individual,integral needle valves with regulating stems for flow adjust-ment.5.3.4 The total system accuracy shall meet or exceed thefollowing tolerances:5.3.4.1 Inlet
27、pressure regulator within 0.34 kPa (0.05 psig)of setpoint,5.3.4.2 Total flow control system reproducibility within 7 %of full scale, and5.3.4.3 Repeatability of measurement within 0.5 % of fullscale.5.4 Alternative DesignsThe equipment in 5.1 5.3 repre-sents a preferred configuration. Alternative ap
28、paratus designsfor sample heating, and for temperature and flow control shallbe acceptable providing they are shown to maintain tempera-ture and gas flow within the specified limits.5.5 Glassware (Note 3), is used to contain the test sample,deliver gas into the sample, and collect, carry off or retu
29、rncondensable volatiles.NOTE 3Not all glassware is used in a single test procedure.5.5.1 Test Cell, borosilicate glass, standard wall; 38 mmoutside diameter, 300 mm 6 5 mm length, with open end fittedwith a 34/45 standard-taper, ground-glass outer joint (Note 4).See Fig. 2.NOTE 4Initial lots of glas
30、sware were made with 45/50 standard-taper,ground-glass joints. These are also acceptable for test work; however, the34/45 joints are preferred.5.5.2 Condenser, Allihn-Type, borosilicate glass, 330 mm 65 mm jacket, 34/45 standard-taper ground-glass inner joint onlower end. Upper opening must admit ga
31、s delivery tube. SeeFig. 2.5.5.3 Gas Inlet Tube I, 8-mm outside diameter, 850 mm 65 mm long, lower end with fused capillary 1.5 mm to 3.5 mminside diameter. The capillary bore shall be at 15 mm 6 1mmlong. The lower tip is cut at a 45 angle. The gas inlet tube mayoptionally include a glass ring 15 mm
32、 in diameter to supportwasher-type catalysts, or the support ring (see 5.5.8), fromwhich catalyst specimens may be suspended. The position ofthe ring on the gas inlet tube shall be specified in the testmethod requiring such catalyst support. The gas inlet tube I isillustrated in Fig. 2 with a glass
33、ring suitable for support ofwasher-type catalyst.5.5.3.1 The 850 mm tube is required for testing configura-tions using the condenser and sampling head or the interme-diate head in order that the tube extend beyond the top of thecondenser so that a gas supply hose can be attached. A tube ofshorter le
34、ngth may be substituted when other assemblies areused, provided it is long enough to attach the gas supply.5.5.4 Gas Inlet Tube II, 8 mm outside diameter 455 mm 65 mm long, lower tip cut at 45 angle. The top 50 mm of thetube may optionally be bent at a 90 angle. See Fig. 2.5.5.5 Basic Head, with 34/
35、45 standard-taper, ground-glassinner joint, opening for gas inlet tube, septum port for samplewithdrawal, and exit tube to conduct off-gases and entrainedvapors. Overall length shall be 125 mm 6 5 mm. The headshall have an adapter by which an air-tight seal may be madewith the gas inlet tube.3The se
36、ptum port is preferably designedto accept a flat polytetrafluoroethylene (PTFE)-faced siliconeseptum such as used with gas chromatographic instrumenta-tion. See Fig. 3.5.5.6 Intermediate Head, with standard-taper inner joint atbottom for test cell and outer joint at top for condenser. Overalllength
37、shall be 170 mm 6 5 mm. The outlet for removal ofoff-gases and condensed liquids is located far enough belowthe gas-escape holes to ensure that condensed liquid will exitthrough the side tube rather than returning to the test cell. Aseptum port (same as in 5.5.5) is provided for sample with-drawal.
38、See Fig. 3.5.5.7 Sampling Head, with standard-taper inner joint atbottom for test cell and outer joint at top for condenser. Overalllength shall not exceed 175 mm. A septum port (same as in5.5.5) is provided for sample withdrawal. See Fig. 3.3A Wheaton-type thermometer adapter is suitable, with an O
39、-ring seal. Allwetted parts should be of poly-tetrafluoroethylene (PTFE) or similar inert material.FIG. 2 ApparatusD4871 11 (2016)35.5.8 Support Ring, 9.5 mm inside diameter, 12.7 mm out-side diameter, 7 mm long, to fit on inlet tube I fitted withhigh-mounted glass ring. Four glass hooks are spaced
40、at 90intervals from which catalyst coupons may be suspended. SeeFig. 3.5.5.9 Spacer Ring, 9.5 mm inside diameter, 12.7 mm out-side diameter, 7 mm long, to fit on inlet tube I fitted withlow-mounted glass ring. The spacer is added to separate metalwashers used as catalyst and corrosion test specimens
41、. See Fig.3.6. Procedure6.1 Test Conditions:6.1.1 Stability tests can be run for a fixed time period, withmeasurement of selected parameters at the end of the testperiod or at intervals throughout the test.6.1.2 Stability tests can be run until a predetermined failurepoint, with measurement of selec
42、ted parameters to determinefailure. Samples of fluid are withdrawn at intervals to measurechanges in the parameters.6.1.3 Fixed time tests are convenient for setting perfor-mance specifications; variable time tests can offer more usefulinformation in screening tests and evaluating formulationchanges
43、.6.2 Possible test parameters that can be monitored include:6.2.1 Change in acid number (Test Methods D664, D974,D3339,orD5770),6.2.2 Change in precipitation number (Test Method D91),6.2.3 Change in viscosity (Test Method D445),6.2.4 Change in color of fluid (Test Methods D156 orD1500),6.2.5 Evapora
44、tion loss from test fluid,6.2.6 Formation of an insoluble sludge,6.2.7 Formation of a spot on a test blotter,6.2.8 Formation of varnish,6.2.9 Change in weight of catalyst specimens,6.2.10 Change in appearance of catalyst specimens,6.2.11 Weight of material volatilized from sample, and6.2.12 Acid num
45、ber of volatilized material (Test MethodD3339 or D5770).7. Keywords7.1 accelerated testing-petroleum products; gear oil-stabilitytest apparatus; hydraulic oil-stability test apparatus; oxidationtesting-petroleum; stability-oxidation; stability-thermal; tur-bine oil-stability test apparatus; universa
46、l oxidation test appa-ratusASTM 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 rights, and the riskof infri
47、ngement 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 for revision of this standar
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