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Brookfield Engineering

Viscosity Glossary

3A
a US industrial standard for process equipment design; required certification for clean-in-place capability.

Absolute Viscosity
the viscosity value associated with a Newtonian material

ASTM
American Society of Testing and Materials. United States organization responsible for establishing test standards.

Autorange
feature on standard Brookfield digital Viscometers/Rheometers which provides maximum viscosity value that can be measured using a specific spindle at a designed rpm.

bob
spindle used with PVS Rheometer;
also referred to as "bob/stator" because it does not rotate on this instrument. The sample cup rotates instead, causing the shearing action.

°C
a scientific unit of measurement for temperature; expressed as "degrees Celsius" or "degrees Centigrade."

Centipoise
a unit of measurement in the cgs system for viscosity; abbreviated cP.

Comm Port
the communications channel on a PC/computer via which data is transmitted.

Concentric Cylinder
a cylinder within a cylinder. For viscosity measurement, a cylindrical spindle rotates within a cylindrical chamber. Also known as "Coaxial Cylinder" because both cylinders have the same center line.

Cone Spindle
an almost flat circular spindle which has a small angle relative to the cup or plate on which it rotates.

CP or C/P
Brookfield terminology for cone and plate geometry.

Cylindrical Spindle
a spindle shaped like a cylinder.

Disc Spindle
a spindle having a flat circular disc near the bottom of the rod. The shape of the disc spindle makes the calculation of Shear Rate an approximation or average across the surface of the disc.

DIN
Deutsche Industrie Normung, German organization responsible for establishing test standards; similar to ASTM in United States.

dyne-cm
a unit of measurement for torque.

°F
a scientific unit of measurement for temperature; expressed as "degrees Fahrenheit."

Fluid Ounce
a scientific unit of measurement for volume; abbreviated as oz.

Footprint
the bench space or area required for an item of equipment.

Gallon
a scientific unit of measurement for volume; abbreviated as gal.

Gap
the distance between the spindle and the chamber or cup in which the spindle is rotating.

Gram
a scientific unit of measurement for weight; abbreviated as gm.

Guard Leg
the protective bracket for spindles supplied with standard Brookfield LV and RV Viscometers/Rheometers.

HA
Brookfield torque range appropriate for measuring medium to high viscosity materials.
100% torque = 14,374 dyneocm.

HB
Brookfield torque range appropriate for measuring high viscosity materials.
100% torque = 57,496 dyneocm.

5xHB
Brookfield torque range appropriate for measuring "very" high viscosity materials.
Five times that of HB.
100% torque = 287,480 dyneocm.

Hz
unit of measurement for frequency; expressed as "Hertz" or "cycles per second."

In-line
process viscometer placement in a pipe.

KREBS Unit
a unit of viscosity measurement obtained when using a KREBS spindle rotating at 200 RPM; commonly used in the paint and coatings industry.

LCD
liquid crystal display

LED
light emitting diode display

Liter
a scientific unit of measurement for volume; abbreviated as L.

LV
Brookfield torque range appropriate for measuring low viscosity materials.
100% torque = 673.7 dyneocm.

mA
a scientific unit of measurement for current flow; expressed as "milliamp."

milli Liter
a scientific unit of measurement for volume; abbreviated as mL.

micro Liter
a scientific unit of measurement for volume; abbreviated as mL.

milli-Pascal seconds
a unit of measurement for viscosity; abbreviated as mPaos.

NIST
National Institute of Standards and Technology. US Government organization responsible for test standards.

Newtonian
a material whose viscosity value is the same at all shear rates.

Non-Newtonian
a material whose viscosity changes as shear rate changes.

On-line
use of a process viscometer to provide continuous viscosity measurement of a material during processing.

PC
personal computer.

pH
positive hydrogen ion index. Characterizes degree of acidity or alkalinity in a material.

Pint
a unit of measurement for volume; abbreviated as pt.

Plate Spindle
a flat circular spindle used to measure visco-elastic materials or materials containing particulate matter.

Pneumatic
air operated

Poise
a unit of measurement for viscosity; abbreviated as P.

PP
Brookfield terminology for plate and plate geometry.

Relative Viscosity
the viscosity value of a non-Newtonian material at a defined shear rate.

Rheology
the science which studies the deformation and flow of materials.

Rheometer
an instrument that measures the flow behavior of materials.

RPM
rotations per minute; a unit of measurement for spindle speed.

RS-232
data transfer protocol in the computer industry.

RTD
resistance thermal detector; type of sensor for measuring temperature

RV
Brookfield torque range appropriate for measuring medium viscosity materials.
100% torque = 7,187 dyneocm.

sec-1
the scientific unit of measurement for shear rate; expressed as "reciprocal seconds" or "inverse seconds."

Shear Rate
the velocity gradient in a flowing material; the shape and rotational speed of the spindle rotating in a chamber or cup are used to calculate shear rate.

Shear Stress
the force per unit area used to move a material.

Spindle Geometry
the shape of a spindle. Brookfield spindles supplied with standard Viscometers/Rheometers (Dial Reading, DV-E, DV-I+, DV-II+Pro, DV-III+) are disc type. Other choices include Cylindrical, Cone, Plate, KREBS, etc.

Time to stop
Brookfield test procedure in DV-I+ and DV-II+ Viscometers which measures the viscosity of a material after a specified time interval.

Time to torque
Brookfield test procedure in DV-I+ and DV-II+ Viscometers which measures the time interval required to reach a specified torque value.

Torque Range
the torque measurement capability of a Brookfield Viscometer/Rheometer measured in dyneocm; designations such as LV, RV, HA or HB are used to define the Torque Range for a specific instrument.

Torque %
the amount of torque resistance measured by a rotating spindle immersed in a material.

Volt
unit of measurement for voltage unless otherwise indicated; abbreviated as V.

Viscometer
an instrument that measures the viscosity of materials.

Viscosity
the resistance of a material to flow.
Viscosity = shear stress/shear rate

Viscosity Range
the operating range of a Brookfield instrument using the spindle(s) identified.

Yield Stress
the amount of force required to cause a material to flow.

CONVERSION TABLES
Viscosity

1 cP = 1 mPa·s
1 P = 100 cP
1 Pa·s = 1,000 mPa·s

Sample Volume

1 L = 1000 mL
1 mL = 1000 mL
1 gal = 8 pt. = 3.7 L
1 pt = 16 oz.

Torque Range

LV = 673.7 dyneocm
RV = 7,187 dyneocm
HA = 14,374 dyneocm
HB = 57,496 dyneocm
5xHB = 287,480 dyneocm

Temperature

°C = 5/9 (°F-32)

Please refer to Brookfield's publication
"More Solutions to Sticky Problems" for a detailed explanation of viscosity and Brookfield methodology for making measurements.