Cannon Instrument miniPV Addendum - Manual (Page 6)

Following is a synopsis of the calculations used for viscosity
determination.
Absolute viscosity, n, is defined by the equation: n = Ctr - Er/t2
Where:
C = tube calibration constant (cSt/s)
t = flow time (seconds)
r = is the solution (or solvent) density (g/ml)
E = kinetic energy correction constant (cSt·s2)
Rules for calculations
The VISCPRO® software will calculate for viscosity based on all
available data. The following rules govern the method of calculation,
including calculation in the event of missing information:
1. In cases where sample density and/or tube calibration constants are
unknown (set to default values r = “1”, C = “1”, E = “0”), absolute
viscosity is reported as “N/A” (not available) in relative viscosity
analyses. This is because the absolute viscosity cannot be reliably
calculated in the absence of this information.
2. The only exception to the rule above occurs when density and tube
constants are available for the solvent blank in a relative viscosity
determination. In that event, the absolute viscosity of the sample can
be calculated using the absolute viscosity of the solvent blank and
the relative viscosity value that was automatically calculated for the
solution at the time of the test (see relative viscosity equation, next
page).
For additional rules relating to relative viscosity calculations, see the
section
on relative viscosity calculation, following.
Kinematic viscosity, v, is defined by the equation:
v = Ct - E/t 2
Where: v =
kinematic viscosity (cSt)
C = tube calibration constant (cSt/s)
E = kinetic energy correction constant (cSt·s 2 )
t = flow time (seconds)
Relative Viscosity is defined by the equation:
) /t E - t (C
) /t E - t (C
2
0 0 0 0 0
2
1 1 1 1 1
ρ
ρ
=
rel
n
Where:
ρ = density
1. The tube calibration constants (C) are only factored into the relative
viscosity equation if constant actual values (not default values) for
the solution and the solvent blank were available at the times the
blank and the solution were tested.
2. The kinetic energy correction, E, is used in relative viscosity
calculations only if both tube calibration constants (C and E values)
are available for both the solution and the solvent blank.
3. Density is factored into relative viscosity equations only if available
for both the solution and the solvent blank ( ρ│1).
NOTE