M19-354
Page 5
©
2019 AMETEK Brookfield Inc. All rights reserved.
I. INTRODUCTION
Falling Ball Viscometer, Model KF40, complies with the German industry standard DIN 53015.
The measuring principle, according to Höppler, is to determine the falling time of a ball in a
cylindrical glass tube filled with liquid. The working angle of the falling tube in the KF40
are variable at 80°, 70°, 60° and 50°
relative to horizontal. The water jacket, surrounding the
falling tube, when connected to a Brookfield circulating temperature bath provides for precise
temperature control of the sample.
The user calculates the dynamic viscosity of the sample by determining the falling time of the
ball between the upper and lower ring marks displayed on the falling tube. Using data on the
ball constants, the density difference between the liquid sample and the ball, and the working
angle constant, a mathematical equation is used to convert the time measurement to a viscosity
value in centipoise.
Note:
The ball constants (forwards and backwards) and ball densities are listed on the test
certificate accompanying the instrument. You must provide the density value for the
liquid that you are testing.
The six (6) balls with different diameters and densities enable the KF40 to measure a wide
range of viscosities. The ability to adjust the angle of inclination extends the measuring range
for low viscosity liquids.
For non-Newtonian liquids, by subjecting the same sample to repetitive measurements with the
KF40 at different angles, pseudoplastic or dilatant behavior may be determined as explained in
Section IV. Time dependent behavior (thixotropy and rheopexy) may also be noted.
The ease of operation and precise temperature control, using a Brookfield circulating temperature
bath, allows for very reproducible measuring results.
I.1 Components
Component
Part No.
Quantity
KF40 Falling Ball Viscometer
KF40
1
Set of (6) balls with gauge (FB68) in a carrying case (FB26)
FB30C
1
Supplied w/certificate stating diameter and mass of each ball
-Ball 1 (glass)
FB1
-
-Ball 2 (glass)
FB2
-
-Ball 3 (nickel and iron)
FB3
-
-Ball 4 (nickel and iron)
FB4
-
-Ball 5 (steel)
FB5
-
-Ball 6 (steel)
FB6
-
Ball Tweezers
FB51
1
Wire Cleaning Brush for Sample Tube
FB53
1
Brush to clean loose debris from Falling Balls
FB52
1
