Brookfield Falling Ball KF20 - Manual (Page 11)

Brookfield Engineering Labs., Inc. Page Manual No. M09-352-B04
to the air bubbles. Due to the design of the upper locking plug, air bubbles cannot get into
the sample tube.
• The sample must be free of air bubbles between the two locking plugs. The lid of the up-
per locking plug is attached and the temperature control (desired test temperature) must be
achieved. After proper temperature control is achieved, the upper cap is screwed on.
Do not heat the sample with the upper lid attached as pressure may build in the tube.
NOTE: Gas bubbles can be removed by warming up the sample for a short time (approxi-
mately 20 degrees above the measuring temperature with the upper locking plug
removed) or by lightly tapping on the lid of the upper locking plug.
II.3 Temperature Control of the Sample
The following are suggested working fluids for the circulating temperature bath:
Temperature
Range
Bath Working Fluids Tubing
-60 to +20°C Water (deionized) - glycol-mixture; mixed
in accordance with the manufacturer’s
instructions for the temperature range
Insulated Perbunan tubing,
secured with tube band clips
+1°C to +90°C Distilled water Perbunan tube
+90°C to +150°C Transparent thermostatic oil Insulated Vitons tube, se-
cured with tube band clips
The tubing from the circulating bath should be pushed tightly onto the viscometer tubes. By
pulling gently, check whether the tubing is firmly attached. Tubing and circulating bath are
available on request from your Brookfield dealer. If the water bath jacket has condensation on
the glass, rub with alcohol.
The sample tube is sealed with the upper cap after temperature set point has been achieved.
Allow 30 minutes for thermal equilibrium.
Falling ball viscometers provide precise temperature control for the sample. By measuring
your sample at multiple temperatures, you can determine the temperature viscosity curve.