ASTM D1092-2005 Standard Test Method for Measuring Apparent Viscosity of Lubricating Greases《润滑脂测量表观粘度的标准试验方法》.pdf

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1、Designation: D 1092 05An American National StandardStandard Test Method forMeasuring Apparent Viscosity of Lubricating Greases1This standard is issued under the fixed designation D 1092; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revisi

2、on, 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 test method cov

3、ers measurement, in poises, of theapparent viscosity of lubricating greases in the temperaturerange from 54 to 38C (65 to 100F). Measurements arelimited to the range from 25 to 100 000 P at 0.1 s1and1to100 P at 15 000 s1.NOTE 1At very low temperatures the shear rate range may be reducedbecause of th

4、e great force required to force grease through the smallercapillaries. Precision has not been established below 10 s1.1.2 This standard uses inch-pound units as well as SI(acceptable metric) units. The values stated first are to beregarded as standard. The values given in parentheses are forinformat

5、ion only. The capillary dimensions in SI units in Fig.A1.1 and Fig. A1.2 are standard.1.3 This 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 a

6、nd determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D88 Test Method for Saybolt ViscosityD 217 Test Methods for Cone Penetration of LubricatingGreaseD 3244 Practice for Utilization of Test Data to DetermineConformance with Specifications3

7、. Terminology3.1 Definitions:3.1.1 apparent viscosity, nof a lubricating grease is theratio of shear stress to shear rate calculated from Poiseuillesequation, and is measured in poises (see 10.1).3.1.2 capillary, nFor the purpose of this method, a capil-lary is any right cylindrical tube having a le

8、ngth to diameterratio of 40 to 1.3.1.3 shear rate, nthe rate at which a series of adjacentlayers of grease move with respect to each other; proportionalto the linear velocity of flow divided by the capillary radius,and is thus expressed as reciprocal seconds.4. Summary of Test Method4.1 The sample i

9、s forced through a capillary by means of afloating piston actuated by the hydraulic system. From thepredetermined flow rate and the force developed in the system,the apparent viscosity is calculated by means of Poiseuillesequation.Aseries of eight capillaries and two pump speeds areused to determine

10、 the apparent viscosity at sixteen shear rates.The results are expressed as a log-log plot of apparent viscosityversus shear rate.5. Significance and Use5.1 Apparent viscosity versus shear rate information can beuseful in predicting pressure drops in grease distributionsystems under steady-state flo

11、w conditions at constant tem-perature.6. Apparatus6.1 The assembled pressure viscometer consists of fourmajor divisions, the power system, the hydraulic system, thegrease system (described in the annex and shown in Fig. 1),and a bath of optional design. Fig. 2 is a photograph of the firstthree divis

12、ions as commonly used at room temperature. Thisform of the apparatus can be used with a cylindrical insulatedtank 178 mm (7 in.) in diameter and 508 mm (20 in.) deep. Thebath medium may be kerosene or alcohol cooled manually withdry ice. Alternatively the grease system, the grease andhydraulic syste

13、m, or all three major divisions can be built intoany liquid or air bath that will cover the temperature range andmaintain the grease at test temperature 60.25 C (60.5F).1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibil

14、ity of SubcommitteeD02.G0 on Lubricating Grease.Current edition approved Nov. 1, 2005. Published November 2005. Originallyapproved in 1950. Last previous edition approved in 1999 as D 109299.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serv

15、iceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.7. Sampling7.1 A single filling of the grease cylinder

16、requires about0.223 kg (12 lb) of grease which is the minimum size sample.NOTE 2It is possible for an experienced operator to complete the 16single determinations with a single filling. However, some samples reachthe equilibrium pressure slowly, making it advisable to have a sample ofseveral pounds

17、available.7.2 Generally no special preparation of the sample is nec-essary.NOTE 3The apparatus works the samples to some extent as they passthrough the capillary. Somewhat better precision is obtained if they arepreviously worked as described in Test Methods D 217. Working of somegreases may cause a

18、eration.NOTE 4It is desirable to filter some greases through a 60-mesh screento prevent plugging the No. 8 capillary. Follow prudent laboratory practiceto keep equipment cleaned and flushed before use.8. Calibration and Standardization8.1 To calibrate the hydraulic system, remove the greasecylinder

19、and replace it with a needle valve. Select a hydraulicoil of about 2000 cSt (2000 mm2/s) viscosity at the testtemperature. Fill the system with hydraulic oil and circulate theoil until it is free of air bubbles. At atmospheric pressure,quickly place a 60-mL Saybolt receiving flask (Test MethodD88),

20、under the outlet and start a timer. Determine the deliverytime for 60 mL and calculate the flow rate in cubic centimetresper second assuming 1 mL equal to 1 cm3. Repeat thisobservation at 500, 1000, 1500 psi (3.45, 6.89, 10.4 MPa) andat sufficient pressures above 1500 psi to develop a calibrationcur

21、ve of the type as shown in Fig. 3. The developed curve ofthe type is used to correct flow rates when grease is dispensed.Repeat the calibration at intervals to determine if wear ischanging the pump flow.8.2 An alternative procedure for the calibration of thehydraulic system is the measurement of the

22、 rate of flow of thetest grease. To cover the desired range of shear rates, flow ratesFIG. 1 Schematic Drawing of ApparatusFIG. 2 Photograph of ApparatusD1092052over an approximate range of pressure are determined. Anysuitable means of measuring the rate of grease flow may beused.9. Procedure9.1 Cha

23、rge the sample so as to reduce inclusion of air to aminimum. Soft greases may be poured into the cylinder ordrawn up by vacuum; heavy samples must be hand packed.When filling the cylinder by vacuum, remove the capillary endcap and place the piston flush with the open end and then insertinto the samp

24、le. Apply vacuum to the opposite end of thecylinder until the cylinder is fully charged with grease. Thismust be facilitated by tapping with a wooden block. Replacethe capillary end cap and fill the upper end of the cylinderabove the piston with hydraulic oil.9.2 Fill the entire hydraulic system wit

25、h hydraulic oil.Disconnect, invert and fill the gage and gage connections withoil. With the entire hydraulic system connected and completelyfilled with oil, adjust the temperature of the sample to the testtemperature 60.25C (60.5F) as determined by a thermo-couple inserted in the capillary end cap.

26、Operate the pump untiloil flows from the gage connection on the viscometer beforereconnecting the gage. With the entire viscometer assembled,circulate hydraulic oil with the return valve open until all traceof air is eliminated.9.2.1 The time to attain test temperature varies with thebath. At 54C (6

27、5F) the grease in an unstirred liquid bathshould be ready to test in 2 h. Air baths can take as long as 8h. An ASTM Thermometer 74F in the bath serves as aconvenient secondary means of measuring the temperature at54C (65F). In an air bath the thermometer must be within25.4 mm of the capillary.9.3 Wi

28、th No. 1 capillary in place and the 40-tooth gearconnected, operate the pump with the return valve closed untilequilibrium pressure is obtained. Record the pressure. Changeto the 64-tooth gear and again establish equilibrium. Recordand relieve the pressure. Replace the No. 1 capillary withsubsequent

29、 ones and repeat these operations until tests havebeen run with all capillaries at both flow rates. With some softor hard greases, it cannot be practical to use all of thecapillaries.NOTE 5It may be necessary to refill the cylinder with fresh greasewhen all 16 determinations are to be made.10. Calcu

30、lation10.1 Calculate apparent viscosity of the grease as follows:happarent viscosity! 5 F/S (1)where F is the shear stress, and S is the shear rate. Therefore:h5F/S 5ppR2/2pRL4v/t!/pR35 ppR4/8Lv/t! 5 P68944pR4/8Lv/t! (2)where:p = pressure dynes/cm2,L = capillary length, cm,P = observed gage pressure

31、, psi (multiply by 68944 toconvert to dynes per square centimetre),R = radius of capillary used, cm, andv/t = flow rate, cm3/s.10.2 Calculations may be reduced to a minimum by prepar-ing a table of 16 constants, one for each capillary and shear rate(Table 1). For example, viscosity with No. 1 capill

32、ary and the40-tooth gear is given as follows:h5Pobserved!68944pR4/8Lv/t! or PK140!(3)where:K1240!5 68944 p R4/8Lv/t (4)10.3 Also calculate the shear rates as follows:S 5 4v/t!/pR3(5)Correct the flow rate to correspond to the observed pressureby reference to Fig. 3. Calculate 16 shear rates for the e

33、ightcapillaries and two flow rates. This calculation need not berepeated for each run since it will remain constant untilrecalibration of the pump indicates a revision.10.4 Plot a curve of apparent viscosity versus shear rate onlog-log paper, as shown in Fig. 4.NOTE 6Shear stresses also can be calcu

34、lated by multiplying apparentviscosities by their corresponding shear rates. For solving various prob-lems involving the steady flow of greases, shear stress-shear rate relation-ships may be plotted on appropriate charts. Instructions on the use of thesecharts are given in the article by Rein and Mc

35、Gahey, “Predicting GreaseFlow in Large Pipes,” NLGI Spokesman, April 1965.11. Precision and Bias11.1 Due to the nature of the results, the precision of thistest method was not obtained according to RR:D02-1007,“Manual on Determining Precision Data for ASTM Methodson Petroleum Products and Lubricants

36、.”3The precision of thistest method as determined by statistical examination of inter-laboratory results is as follows:11.2 The data in 11.2.1 and 11.2.2 should be used forjudging the acceptability of results (95 % confidence) accord-ing to the concept of precision as given in Practice D 3244.11.2.1

37、 RepeatabilityThe difference between two test re-sults, obtained by the same operator with the same apparatusunder constant operating conditions on identical test material,would in the long run, in the normal and correct operation ofthe test method, exceed the values given in Table 2 only in onecase

38、 in twenty.3Filed at ASTM International Headquarters and may be obtained by requestingResearch Report RR:D02-1007.FIG. 3 A Typical Pump Calibration CurveD109205311.2.2 ReproducibilityThe difference between two singleand independent results obtained by different operators work-ing in different labora

39、tories on identical test material would, inthe long run, in the normal and correct operation of the testmethod, exceed the values given in Table 2 only in one case intwenty.TABLE 1 Suggested Data Sheet for Recording Test Results (With Illustrative Test Values)Sample . .No. 2 Grease Temperature .25CD

40、ate. .Nov. 1, 1948 Operator. .R.S.123 4A5B6A7CCapillary GearObservedPressure,P, psiK = 68944pR4/(8Lv/t)ApparentViscosity,n poises,= P 3 KShear Rate,S,s1=(4v/t)/pR3Shear Stress,dynes per sqcm = n 3 S1 40 25.5 28.10 716 15 10 7402 40 38.3 6.83 267 61 16 3003 40 48.8 3.61 176 120 21 1004 40 63.5 1.90 1

41、20 230 27 8005 40 96.5 0.89 86 480 41 3006 40 125 0.58 72.6 755 54 8007 40 286 0.139 39.8 3 140 125 0008 40 546 0.0464 25.3 9 320 235 5001 64 29.5 17.60 520 24 12 4702 64 45.8 4.27 195 98 19 1003 64 60 2.26 135.5 195 26 4004 64 82.3 1.19 97.9 370 36 2505 64 130 0.556 72.4 770 55 8006 64 165 0.363 59

42、.9 1 220 73 2007 64 384 0.087 33.4 5 020 167 5008 64 720 0.029 20.9 14 900 311 000AValues in this column are predetermined.BColumn 3 times Column 4.CColumn 5 times Column 6.FIG. 4 Typical Chart for Apparent Viscosity versus Shear RateD109205411.2.3 Reproducibility of the curve drawing operation var-

43、ies from 5 to 8 % for the above samples. These data are basedupon curve values of apparent viscosity at the six shear rates.A separate curve was drawn for each run.11.3 BiasSince there is no accepted reference materialsuitable for determining the bias for the procedure in TestMethod D 1092, bias has

44、 not yet been determined.11.4 There is no research report on Test Method D 1092because this test method was developed before research reportguidelines were instituted, and are no longer available.12. Keywords12.1 apparent viscosity; capillary; lubricating grease; shearrate; viscosityANNEX(Mandatory

45、Information)A1. APPARATUS FOR GREASE SYSTEMA1.1 ApparatusAssembled pressure viscometer appara-tus consists of four major parts: the power system, thehydraulic system, the grease system as shown in Fig. 1 and Fig.2 and constructed as described in A1.2-A1.6, and a bath ofoptional design.A1.2 Power Sys

46、tem, consisting of a13-hp, 1750-rpm induc-tion motor coupled to a 200 to 1 speed reducer. Interchangeable40 and 64-tooth gears are used to drive the hydraulic pump.A1.3 Hydraulic System, consisting of a gear pump fittedwith saddle mount and 42-tooth drive gear,4a hydraulic oilreservoir having a capa

47、city at least equal to that of the greasecylinder and fitted with a 50-mesh screen shall be provided.The pump and grease cylinder shall be connected with highpressure valves and fittings as shown in Fig. 1. Means shall beprovided for connecting interchangeable test gages.A1.4 GagesSince the gages ar

48、e used only in the middlerange, several are desirable to cover a wide variety of greases.Four gages having ranges from 0 to 60 (0.41), 0 to 100 (0.689),0 to 600 (4.14), and 0 to 4000 (27.58) psi (MPa) have beenfound suitable. Alternatively, the gages may be manifolded,provided proper means of elimin

49、ating air from the system isemployed (Fig. 1).A1.5 Grease Cylinder Assembly, consisting of cylinder,floating piston, and caps constructed to conform to the toler-ances shown in Fig. A1.1 with the piston moving the entirelength of the cylinder without appreciable friction. The cylin-der shall be constructed to withstand a working pressure of4000 psi (27.5 MPa). The exterior features and method offastening may be modified.A1.6 CapillariesCapillaries, eight of stainless steel andconforming to dimensions shown in Fig. A1.2, shall compri