Brookfield Spiral Adapter - Manual (Page 5)

Brookfield Engineering Labs., Inc. Page 5 Manual No. M93-270-D0812
I. INTRODUCTION
When used with any Brookfield Viscometer/Rheometer, the Spiral Adapter can measure fluid viscosity
at various 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 Viscometer/Rheometer and is also available as a
pdf file on the Brookfield website.
The Spiral Adapter has an inner, threaded spindle surrounded by a concentric outer cylinder, as shown in
Figure 1
. This combination causes the sample to be continuously pumped up through the gap between
the rotating spindle and the outer cylinder. The material reaches a steady state of flow during which
viscosity is measured.
Sample
Material
Paste
Container
Spiral
Chamber
Spiral
Spindle
Figure 1
The principle of viscosity measurement is to drive the spiral spindle (which is immersed in the test
fluid) through a calibrated spring in the Viscometer/Rheometer. The viscous drag of the fluid against
the spindle is measured by the spring deflection.
The measuring range of the Spiral Adapter [in centipoise (cP) or milliPascal seconds (mPa•s)] is
determined by the rotational speed of the spindle, the length and effective diameter of the spindle, the
length and diameter of the chamber the spindle is rotating in, and the full scale torque of the viscometer’s
calibrated spring.