Brookfield DV-III Rheometer - Manual (Page 3)

Brookfield Engineering Laboratories, Inc. Page 3 Manual No. M/98-211-A0701
I. INTRODUCTION
The Brookfield DV-III+ Programmable Rheometer measures fluid parameters of Shear Stress and
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-III+.
The principle of operation of the DV-III+ 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 measuring range of
a DV-III+ (in centipoise) 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 mN•m
LVDV-III+ 673.7 0.0673
RVDV-III+ 7,187.0 0.7187
HADV-III+ 14,374.0 1.4374
HBDV-III+ 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).
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).
The equivalent units of measurement in the SI system are calculated using the following conver-
sions:
SI CGS
Viscosity: 1 mPa•s = 1 cP
Shear Stress: 1 Newton/m 2 = 10 dyne/cm 2
Torque: 1 N•m = 10 7 dyne•cm
References to viscosity throughout this manual are done in CGS units.
WARNING: Use of this instrument in a manner not specified by Brookfield may result in incorrect
readings or instrument failure. Please read this manual prior to using the instrument.