Cannon Instrument CMRV-4500 - Manual (Page 61)

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CANNON ® Mini-Rotary Viscometer CMRV-4500 Instruction & Operation Manual
Version 1.1e—October, 2011 • CANNON ® Instrument Company
2139 High Tech Road • State College, PA • 16803 • USA
CHAPTER
10
SUMMARY OF TEST PROCEDURE
In the ASTM D 3829, ASTM D 4684 and ASTM D 6821 test methods, a
10-ml sample is placed in a test cell, pre-heated to a specified tempera-
ture, and held at that temperature for a specified time to ensure complete
solution of all components of the oil. The temperature of the cell is then
lowered to the test temperature at a programmed cooling rate. The test
temperature and the cooling program (profile) are determined by the
nature of the sample being tested and by the test method being used.
ASTM D 3829 method ASTM D 3829 uses slow cooling followed by a soak period at the test
temperature and requires about 19 hours for completion of the entire test.
The test is designed for engine oils.
ASTM D 4684 method ASTM D 4684 uses much slower cooling and requires between 45 and
54 hours for completion of the test. (The D 4684 temperature cycle is
sometimes referred to as the TP-1 cycle.) The test is designed for engine
oils.
ASTM D 6821 method ASTM D 6821 uses slow cooling and requires about 18 hours for
completion of the test.The test is designed for drive line lubricants.
ASTM D 6896 method ASTM D 6896 uses slow cooling and requires between 43 and 45 hours
for completion of the test. This test method covers the measurement of
the yield stress and viscosity of used diesel oils.
NOTE CANNON may provide copies of a relevant ASTM Method with your CMRV
instrument purchase. The ASTM D 6821 method is currently provided with
any order for the special drive line rotors available for the MRV. Additional
reprints of the ASTM test methods may be purchased from:
ASTM
100 Barr Harbor Drive
West Conshohocken, PA 19428
The CMRV-4500 determines the yield stress and apparent viscosity of the
sample by measuring the rotational speed of a cylindrical rotor immersed
in the sample in the test cell. For ASTM D 3829, yield stress is measured
by adding 10-gram disks successively until discernible rotation occurs.
Apparent viscosity is then determined by measuring the angular velocity
of the rotor when a 150-gram weight is applied.
ASTM D 4684 method
ASTM Method D 4684 describes the procedure for measuring yield
stress and apparent viscosity. Yield stress is an indication of a structure
that has formed within the oil under the cooling conditions of the test.