1、Designation: D3829 02 (Reapproved 2007)D3829 12Standard Test Method forPredicting the Borderline Pumping Temperature of EngineOil1This standard is issued under the fixed designation D3829; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revi
2、sion, 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.1. Scope Scope*1.1 This test method covers the prediction of the borderline pumping temperature (BPT) of engine
3、oils through the use of a 16-hcooling cycle over the temperature range from 0 to 40C. The precision is stated for temperatures from -34 to -15C.1.2 Applicability to petroleum products other than engine oils has not been determined.1.3 This test method uses the millipascal (mPas), as the unit of visc
4、osity. For information, the equivalent centipoise unit isshown in parentheses.The values stated in SI units are to be regarded as standard. No other units of measurement are included inthis standard.1.3.1 ExceptionThis test method uses the SI based unit of milliPascal second (mPas) for viscosity, wh
5、ich is equivalent tocentipoise (cP).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 practices and determine the applicability of regulatorylimita
6、tions prior to use.2. Referenced Documents2.1 ASTM Standards:E1137 Specification for Industrial Platinum Resistance Thermometers3. Terminology3.1 Definitions:3.1.1 apparent viscosityviscosity, nthe determined viscosity obtained by use of this test method.3.1.2 Digital Contact Thermometer (DCT), nan
7、electronic device consisting of a digital display and associated temperaturesensing probe.3.1.2.1 DiscussionThis device consists of a temperature sensor connected to a measuring instrument; this instrument measures the temperature-dependent quantity of the sensor, computes the temperature from the m
8、easured quantity, and provides a digital output, or displayof the temperature, or both. This device is sometimes referred to as a digital thermometer.3.1.3 Newtonian oil or fluidfluid, nan oil or fluid that at a given temperature exhibits a constant viscosity at all shear ratesor shear stresses.3.1.
9、4 non-Newtonian oil or fluidfluid, nan oil or fluid that at a given temperature exhibits a viscosity that varies withchanging shear stress or shear rate.3.1.5 shear raterate, nthe velocity gradient in fluid flow. For a Newtonian fluid in a concentric cylinder rotary viscometerin which the shear stre
10、ss is measured at the inner cylinder surface (such as the apparatus being described), and ignoring any endeffects, the shear rate is given as follows:1 This test method is under the jurisdiction of ASTM Committee D02 on Petroleum Products and Lubricants and is the direct responsibility of Subcommitt
11、ee D02.07 onFlow Properties.Current edition approved Nov. 1, 2007Nov. 1, 2012. Published January 2008April 2013. Originally approved in 1979. Last previous edition approved in 20022007 asD3829D382902(2007).02. DOI: 10.1520/D3829-02R07.10.1520/D3829-12.This document is not an ASTM standard and is int
12、ended 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. In all cases only the curr
13、ent 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 States1Gr 5 2Rs2Rs22R r2! (1)Gr5 4piRs
14、2tRs22Rr2! (2)where:Gr = shear rate at the surface of the rotor in reciprocal seconds, s1, = angular velocity, rad/s,Rs = stator radius, mm,Rr = rotor radius, mm, andt = time in seconds for one revolution of the rotor.For the specific apparatus being described in 5.1.16.1.1,Gr 563t (3)3.1.6 shear st
15、ressstress, nthe motivating force per unit area for fluid flow. Area is the area under shear. For the rotaryviscometer being described, the rotor surface is the area under shear.Tr59.81MRo1Rt!31026 (4)Sr 5 Tr2piRr2h 3109 (5)where:Tr = torque applied to rotor, Nm,M = applied mass, g,Ro = radius of th
16、e shaft, mm,Rt = radius of the thread, mm,Sr = shear stress at the rotor surface, Pa, andh = height of the rotor, mm.For the dimensions given in 5.1.16.1.1,Tr 531.7M 31026 (6)Sr 53.5M (7)3.1.7 viscosityviscosity, nthe ratio between the applied shear stress and rate of shear. It is sometimes called t
17、he coefficientof dynamic viscosity. This value is thus a measure of the resistance to flow of the liquid. The SI unit of viscosity is the pascalsecond (Pas). The centipoise (cP) is one millipascal second (mPas) and is often used.3.2 Definitions of Terms Specific to This Standard:3.2.1 borderline pum
18、ping temperaturetemperature, nthe maximum temperature at which the critical yield stress or criticalviscosity occurs, whichever is the higher temperature.3.2.2 calibration oilsoils, nthose oils for establishing the instruments reference framework of apparent viscosity versusspeed from which the appa
19、rent viscosities of test oils are determined. Calibration oils, which are essentially Newtonian fluids, areavailable commercially, and have an approximate viscosity of 30 000 mPas (30 000 cP) at 20C.223.2.3 critical viscosityviscosity, nthe maximum viscosity at a defined shear rate to allow adequate
20、 flow of oil to the oil pumpin an automotive engine.Ahigher viscosity can cause failure to maintain adequate oil pressure through the limiting of flow throughthe oil screen or oil inlet tubes.3.2.4 critical yield stressstress, nthe maximum yield stress that allows oil to flow to the inlet oil screen
21、 in an automotiveengine. With a higher yield stress, air may be drawn into the pump and cause failure to maintain adequate oil pressure throughair-binding of the pump.3.2.5 test oiloil, nany oil for which the apparent viscosity and yield stress are to be determined by use of the test methodunder des
22、cription.3.2.6 yield stressstress, nthe shear stress required to initiate flow. For all Newtonian fluids and some non-Newtonian fluids,yield stress is zero. Some engine oils have a yield stress that is a function of their low-temperature cooling rate, soak time, andtemperature.2 The sole source of s
23、upply of the apparatus known to the committee at this time is Cannon Instrument Co., P.O. Box 16, State College, PA 16801. If you are aware ofalternative suppliers, please provide this information to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of th
24、e responsibletechnical committee,1 which you may attend.D3829 1224. Summary of Test Method4.1 An engine oil sample is cooled from 80C to the desired test temperature at a nonlinear programmed cooling rate over a10-h period and held at the test temperature for the remainder of a 16-h period. After co
25、mpletion of the soak period, two standardtorques of increasing severity are applied to the rotor shaft and the speed of rotation in each case is measured. From the resultsat three or more temperatures, the borderline pumping temperature is determined.4.2 Alternatively, for some specification or clas
26、sification purposes it may be sufficient to determine that the BPT is less than acertain specified temperature.5. Significance and Use5.1 Borderline pumping temperature is a measure of the lowest temperature at which an engine oil can be continuously andadequately supplied to the oil pump inlet of a
27、n automotive engine.6. Apparatus6.1 Mini-Rotary Viscometer,2consisting of one or more viscometric cells including a calibrated rotor-stator assembly, which arecontained in a temperature-controlled aluminum block.6.1.1 The viscometric cell has the following nominal dimensions:Diameter of rotor 17.0 m
28、mLength of rotor 20.0 mmInside of diameter of cup 19.0 mmRadius of shaft 3.18 mmRadius of string 0.1 mm6.2 Thermometers,Temperature Measuring DeviceUse either a calibrated DCT described in 6.2.1 or liquid-in-glassthermometers as described in 6.2.2for measuring temperature of the block. Two are requi
29、red, one graduated from at least +70 to90C in 1C subdivisions, the other with a scale from at least 36 to +5C in 0.2C subdivisions The DCT or the calibrated lowtemperature liquid-in-glass thermometer shall be used as the thermometer for temperature measurement independent of theinstruments temperatu
30、re control, and shall be located in the thermowell.NOTE 1The display device and sensor must be correctly paired. Incorrect pairing will result in temperature measurement errors and possiblyirreversible damage to the electronics of the display.6.2.1 A DCT shall meet the following:(1) A range from -45
31、 to 100C with a display resolution to at least 0.01 C.(2) The only acceptable sensors are a resistance temperature device (RTD), such as a platinum resistance thermometer (PRT)or a thermistor that are either glass or metal sheathed.(3) For metal sheathed probe, use a 3 mm diameter probe with a sensi
32、ng element that is less than 30 mm in length; a metalsheathed probe requires a thermowell sleeve measuring 6 mm outside diameter by 58 mm long with a hole in the center toaccommodate the probe. For a glass sheathed probe, use a probe 6 mm in diameter containing a sensing element less than 12 mmin le
33、ngth.(4) A combined (display and probe) minimum accuracy of 650 mK (0.05C).(5) A response time of less than or equal to 25 s as defined in Specification E1137.(6) A drift of less than 50 mK (0.05C) per year.(7) Error of less than 50 mK (0.05C) over the range of intended use.(8) The DCT shall have a
34、report of temperature calibration from a calibration laboratory with demonstrated competency intemperature calibration which is traceable to a national calibration laboratory or metrology standards body.(9) The DCT shall be calibrated over a range from -40 to 85C with at least 4 data points evenly d
35、istributed over the rangeof -40 to -1C. The test report shall include the calibration data.6.2.1.1 The DCT calibration shall be checked at least annually by either measuring the ice point or against a referencethermometer in a constant temperature bath at the prescribed immersion depth to ensure com
36、pliance with 6.2.1 (6 and 7).NOTE 2When a DCTs calibration drifts in one direction over several calibration checks, that is, ice point, it may be an indication of deteriorationof the DCT.6.2.2 Two liquid-in-glass thermometers are required. One shall be a calibrated 76 mm partial immersion thermomete
37、r with ascale from +5C to 1 degree less than the lowest test temperature in 0.2C subdivisions. The low temperature thermometer shallhave a report of calibration showing the temperature deviation at each calibrated test temperature. The second shall be a 76 mmpartial immersion thermometer graduated f
38、rom at least +70 to 90C in 1C subdivisions.6.2.2.1 Calibration CheckVerify the low temperature thermometer at least annually against a reference thermometer in aconstant temperature bath or an ice bath. The thermometer is to be inserted to its immersion depth. If using an ice bath, the icepoint read
39、ing is to be taken within 60 min after the thermometer has been at test temperature for at least 3 min. If the correctedtemperature reading deviates from the reference thermometer or the ice point then repeat this calibration check. If the thermometerdeviates from the reference value on two successi
40、ve checks then a full thermometer recalibration is needed.D3829 1236.2.2.2 RecalibrationA complete recalibration of the liquid-in-glass thermometer, while permitted, is not necessary in orderto meet the accuracy ascribed to liquid-in-glass thermometers design until the thermometers corrected measure
41、d temperaturedeviates from the reference thermometer or ice point by one scale division, or until five years has elapsed since the last fullcalibration.6.3 Temperature Control SystemA means of lowering the temperature to the predetermined test temperature at a controlled,nonlinear rate.6.4 Circulati
42、ng System,2for supplying suitable liquid coolant to the block as needed. Methanol is a suitable coolant. One shouldobserve toxicity and flammability precautions that apply to the use of methanol. The circulating system must be capable ofmaintaining test temperature over a 16-h test period. If methan
43、ol is leaking from the system, discontinue the test and repair theleak before continuing.6.5 Chart Recorder, to verify that the correct cooling curve is being followed, it is recommended that a chart recorder be usedto monitor the block temperature.6.6 Cell CapAcover inserted into the top of the vis
44、cometer cell to minimize room air circulation into the cells is required forthermoelectrically cooled instruments.The cell cap is a stepped cylinder 3861 mm (1.560.05 in.) in length made of a low thermalconductivity material, for example, thermoplastic such as acetyl copolymers that have known solve
45、nt resistivity and are suitablefor use between the temperature ranges of this test method. The top half is 28 61 mm (1.10 60.05 in.) in diameter and the bottomhalf is 19 mm (0.745 in.) in diameter with a tolerance consistent with the cell diameter. The tolerance on the bottom half is suchthat it wil
46、l easily fit into cell but not allow the cap to contact the rotor shaft. The piece has a center bore of 1161 mm (0.43860.05in.). The cap is made in two halves to facilitate placement in the top of the cell.6.6.1 Cell caps shall not be used in the direct refrigeration instruments, since such use woul
47、d block the flow of cold, dry air intothe stators to keep them frost-free.6.7 Supply of Dry GasA supply of dry filtered dry gas to minimize moisture condensation on the upper portions of theinstrument.6.7.1 For thermoelectric cooled instruments, which use cell caps, the dry gas supply is connected t
48、o the housing cover. Thesupply of dry gas is discontinued when the cover is removed for the measurement phase of the test.6.8 Locking PinA device to keep the rotor from turning prematurely and able to stop the rotor at the nearest half revolutionby interaction with the rotor crossbar.7. Reagents and
49、 Materials7.1 Low Cloud-Point, Newtonian Oil,2of approximately 30 Pas (30 000 cP) viscosity at 20C for calibration of theviscometric cells.7.2 Methanol, commercial or technical grade of dry methanol is suitable for the cooling bath.7.3 Oil Solvent, commercial heptanes or similar solvent is suitable.7.4 Acetone, technical grade of acetone is suitable provided it does not leave a residue upon evaporation.8. Sampling8.1 A representative sample of test oil free from suspended solid material and water is neces
