Cannon Instrument CMRV-5000 - Manual (Page 63)

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CANNON ® Mini-Rotary Viscometer CMRV-5000 Instruction & Operation Manual
Version 1.0b—August, 2011; CANNON ® Instrument Company
2139 High Tech Road • State College, PA • 16803 • USA
The temperature profile for this method consists of a 1.5-hour soak at
50°C ± 1°C, a 2-hour nonlinear cool-down to the test temperature, and a
14-hour soak ± 0.02°C at the test temperature. The entire temperature
profile, up to the point of measuring yield stress and viscosity, requires
17.5 hours.
ASTM D 6896 method
For the complete, definitive description of this method, obtain a copy of
the Standard Test Method for the Determination of Yield Stress and
Apparent Viscosity of Used Engine Oils at Low Temperature, Designa-
tion ASTM D 6896.
This test method covers the measurement of the yield stress and viscosity
of used diesel oils after cooling at controlled rates over a period of 43 or
45 hours to a final test temperature of -20 or -25°C. The viscosity
measurements are made at a shear stress of 525 Pa over a shear rate of
0.4 to 15 s
-1 . This method is suitable for measurement of viscosities
ranging from 4,000 mPa-s to 400,000 mPa-s, and is suitable for yield
stress measurements of 7 Pa to >350 Pa. The Method is quite similar to
ASTM D 4684 except that the preheat phase is accomplished in an oven
(not provided with the CMRV) immediately prior to commencing the
temperature profile.
SAE J300 notes
SAE Standard SAE J300, Engine Oil Viscosity Classification tempera-
tures, specified according to the viscosity grade, are as follows:
SAE Viscosity Grade Low-Temperature Pumping Viscosity
(cP Max With No Yield Stress)
0W 60,000 at -40°C
5W 60,000 at -35°C
10W 60,000 at -30°C
15W 60,000 at -25°C
20W 60,000 at -20°C
25W 60,000 at -15°C
Source: SAE J300 Revised DEC99
NOTE The user of the CMRV-5000 is advised to be alert for revisions of the
SAE J300 Viscosity Classification.
Delayed start option
Because of the length of the profile, the starting time should be chosen so
that the test temperature will be reached at a convenient time for testing.
The delayed start option is quite useful for starting the cooling cycle over
a weekend or holiday in preparation for running samples on the follow-
ing business day. For details, see Chapter 11.