Brookfield DV-II+ Programmable Viscometer - Manual (Page 3)

Brookfield Engineering Labs., Inc. Page 3 Manual No. M/97-164-F1 102
I. INTRODUCTION
The Brookfield Programmable DV-II + Viscometer measures fluid viscosity at given shear rates.
Viscosity is a measure of a fluid’s resistance to flow. You will find a detailed description of the
mathematics of viscosity in the Brookfield publication ”More Solutions to Sticky Problems” a copy
of which was included with your DV-II
+ .
The principal of operation of the DV-II + is to drive a spindle (which is immersed in the test
fluid) through a calibrated spring. The viscous drag of the fluid against the spindle is measured
by the spring deflection. Spring deflection is measured with a rotary transducer. The measure-
ment range of a DV-II
+ (in centipoise or milliPascal seconds) is determined by the rotational
speed of the spindle, the size and shape of the spindle, the container the spindle is rotating in, and
the full scale torque of the calibrated spring.
There are four basic spring torque series offered by Brookfield:
Spring Torque
Model dyne-cm milli Newton - m
LVDV-II + 673.7 0.0673
RVDV-II + 7,187.0 0.7187
HADV-II + 14,374.0 1.4374
HBDV-II + 57,496.0 5.7496
The higher the torque calibration, the higher the measurement range. The measurement range for
each torque calibration may be found in Appendix B.
All units of measurement are displayed according to either the CGS system or the SI system.
1. Viscosity appears in units of centipoise (shown as “cP”) or milliPascal-seconds (shown
as “mPa•s”) on the DV-II + Viscometer display.
2. Shear Stress appears in units of dynes/square centimeter (“D/cm 2 ”) or Newtons/square
meter (“N/m 2 ”).
3. Shear Rate appears in units of reciprocal seconds (“1/SEC”).
4. Torque appears in units of dyne-centimeters or Newton-meters (shown as percent “%”
in both cases) on the DV-II + Viscometer display.
Note: To change CGS to SI units on the display - see Section III.2.2.
The equivalent units of measurement in the SI system are calculated using the following conversions:
SI CGS
Viscosity: 1 mPa•s = 1 cP
Shear Stress: 1 Newton/m 2 = 10 dyne/cm 2
Torque: 1 Newton-m = 10 7 dyne-cm
References to viscosity throughout this manual are done in CGS units. The DV-II+ Viscometer
provides equivalent information in SI units.