How to Measure Viscosity with Brookfield Viscometer

How do I use the correct Brookfield Viscometer for viscosity or viscosity measurements?

The following explanation is only a general rule. A more complete explanation of the use of Brookfield Viscometers for each series/model can be found in the Instruction Manual of the viscometer concerned. As an example, the following are the steps to measure viscosity referring to the DV2TLV Viscometer. The way to use other types of Brookfield viscometers is more or less the same.

The full guide to Viscosity Measurement can be downloaded here.

Brookfield Viscometer Parts:

Here are the steps to measure viscosity, how to install a Spindle, how to choose the correct Spindle and RPM.

• Check the completeness of the Viscometer

• Assemble according to the instructions of each instrument.

• Set the tool to a parallel/non-skewed position by looking at the Bubble Level Indicator. If it is not level, adjust the height of the legs by turning the leveling screw.

• Open shipping cap

• Connect with power supply: 220 V / 50 Hz.

• Turn on the tool and follow the on-screen prompts until the Autozeo process is complete.

• Note: for DVE series viscometers and Dial Reading there is no Autozero process.

• Prepare the sample to be measured with a 600 ml Beaker Low Form (8.25 cm diameter) and place it in position.

• Note: The sample container can be replaced, most importantly the Spindle can be dyed to the limit of the dip. Changes in containers will affect the measurement values.

• Dip the spindle into the sample and avoid air bubbles trapped in the sample.

• Attach the spindle by holding and lifting the coupling nut with the left hand while the right hand attaches the spindle by turning to the left. The purpose of lifting the coupling nut is to avoid collision at the Pivot Point. Make sure the motor is OFF.

• Lower the height of the Viscometer position on the Stand/Stand by turning the height control black Knob on the right Stand so that the Spindle is immersed in the sample. Make sure the spindle dip limit matches the markings on each spindle.

Brookfield Viscometer spindle dip limit

• Select the Spindle No. on the Viscometer according to the attached spindle. Note: For Dial Reading series Viscometer there is no facility to select spindle. The results of manual measurements are obtained from the Multiplier Factor Table.

• Select Speed (RPM).
  

Note: The spindle and RPM selection process for samples whose viscosity range is not yet known is carried out by trial and error. The right choice will result in %Torque between: 10-100%. If the %Torque is less than 10%, then the measurement result is considered invalid, the spindle or RPM selection must be replaced. If %Torque > 100% then the measurement result is Error (out of range). The following two general rules will help in the trial and error process in choosing Spindle and RPM.

1. The measuring range is directly proportional to the Spindle number.

2. The measuring range is inversely proportional to the rotation speed.

In other words: to measure high viscosity, choose a large spindle number and/or a low speed (RPM). If the selected spindle and speed combination results in a reading above 100%, reduce the speed or choose a spindle with a larger number. In non-Newtonian fluids it can result in different viscosity values if the spindle and/or velocity are changed.

• Run the viscometer by pressing RUN or Motor ON.

• Record the measurement results displayed on the viscometer display. For Dial Reading/Analog/Manual viscometers, the viscosity value is obtained by multiplying the %Torque displayed on the scale by the times factor in the following table:

Brookfield Type Viscometer Multiplier Factor Table: RV, HA and HB

Factor Finder / Brookfield Viscometer Multiplier Factor Analog Type LV

For example, if you measure viscosity using an LVT Viscometer and the reading is on a scale of 70, then the actual viscosity value is as follows. :

• Type Viscometer : LVT

• Spindle No. : 62

• Rotary speed : 12 RPM

• Spindle multiplier factor 62 at 12 RPM on Table : 25

• Actual Value : 70 x 25 = 1,750 cP

IMPORTANT NOTE :

The measurement results are considered valid, if they meet the following 2 criteria.

1. %Torque is in the value range: 10 – 100%

2. The spindle has rotated at least 5 times

As long as the 2 criteria above are met, the measurement results are valid. Viscosity measurement is a relative result that depends on the variables at the time of measurement.