Cannon Instrument miniAV-LT - Manual (Page 6)

CANNON ® miniAV-LT Automatic Viscometer with VISCPRO ® Instruction & Operation Manual
Version 1.a— May, 2009; CANNON ® Instrument Company
2139 High Tech Road • State College, PA 16803 • USA
2
Measuring kinematic viscosity
Kinematic viscosity is a measure of the internal resistance to flow of a
fluid under gravity with the pressure head being proportional to the
density of the fluid. For any particular viscometer, the time of flow of a
fixed volume of fluid is directly proportional to its kinematic viscosity.
Units of measure An accepted unit of kinematic viscosity is one centimeter squared per
second, which is called one stoke. The centistoke (which is equivalent to
1 mm
2 /s) is the unit of measure most frequently used.
Methodology
ASTM Methods D445 and D2532, describe appropriate test methodolo-
gies and instruments for glass capillary viscometry.
Manual viscometers
Sections 9 through 11 of ASTM D445 provide detailed instructions for
using manual viscometers.
Automatic viscometers
For automatic viscometers, ASTM D445 Section 6.1.2 states, “Auto-
mated apparatus may be used as long as they mimic the physical condi-
tions, operations or processes of the manual apparatus they replace ... The
automated apparatus shall be capable of determining kinematic viscosity
of a certified viscosity reference standard within the limits stated ...”
Thus, automated viscometers can be used with flow times less than 200
seconds, as long as the kinetic energy correction and precision require-
ments are met.
miniAV-LT tube characteristics Each standard miniAV-LT viscometer tube has one bulb. The normal flow
times for each bulb are 40-400 seconds. Each tube has a ten fold mea-
surement range (for example, range from 1-10 cSt or 1000-10000 cSt ).
NOTE CANNON ® Instrument Company has not recommended the use of
longer flow times with the miniAV-LT, as shorter flow times allow greater
productivity. With longer flow times, the sample throughput would be
significantly reduced. However, the viscometer and software design does
permit longer efflux times (up to 600 seconds) as desired by the user.
Safety cautions
Please observe the following safety procedures and notices for proper
operation of the miniAV-LT:
Do NOT lift the unit by the side panel “ears”. Always support the
unit from the base when moving or lifting.