Brookfield Dial Stepper Viscometer - Manual (Page 5)

Brookfield Engineering Laboratories, Inc. Page 5 Manual No. M00-151-H0612
I. INTRODUCTION
The Brookfield Dial Reading 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 Dial Viscometer. The Dial Viscometer rotates a sensing element in a fluid and
measures the torque necessary to overcome the viscous resistance to the induced movement. This
is accomplished by driving the immersed element, which is called a spindle, through a beryllium
copper spring. The degree to which the spring is wound, indicated by the red pointer, is proportional
to the viscosity of the fluid.
The Viscometer is able to measure over a number of ranges since, for a given spring deflection, the
actual viscosity is proportional to the spindle speed and is related to the spindle's size and shape.
For a material of given viscosity, the resistance will be greater as the spindle size and/or rotational
speed increase. The minimum viscosity range is obtained by using the largest spindle at the highest
speed; the maximum range by using the smallest spindle at the slowest speed.
There are four basic spring torque series offered by Brookfield:
Model Spring Torque (Dyne-cm)
LV 673.7
RV 7,187.0
HA 14,374.0
HB 57,496.0
The higher the torque calibration, the higher the measurement range. The viscosity measurement
range for each torque calibration may be found in Appendix A.
All units of measurement are calculated in units of centipoise (cP) by using a look-up table
known as "the Brookfield Factor Finder" to convert torque reading. The equivalent units of
measurement in the SI system are calculated using the following conversions:
CGS SI
Viscosity: 1 cP = 1 mPa•s
Torque: 10
7
dyne-cm = 1 Newton•m
I.1 Components
The following items are provided with your instrument:
Quantity Description Part No.
1 Dial Reading Viscometer Depends on Model (Spring Torque)
1 Laboratory Stand Model A
1 Spindle Set (depends on torque range) SSL (LV 61-64, formerly called LV 1-4) or
SSR (RV 2-7) or
SSH (HA/HB 2-7)
1 Guard Leg B-20Y (LV) or
B-21Y (RV) or
No guardleg for HA/HB torque range
1 Power Supply AV-6 115 includes DVP-65 Power Cord
AV-6 230 includes DVP-66 Power Cord