GAOTek proudly presents a wide range of viscometers. A viscometer is used to measure the viscosity of a fluid or liquid under a certain flow conditions. Thus, viscometers only measure under one flow condition. Different types of viscometers have either the fluid stationary which allow object to pass through or vice versa. Therefore, these devices measure the drag caused by the interaction between the fluid and object surface.
GAOTek provide exceptional selection of high-quality rotational viscometers. Rotational viscometers determine the function of the fluid’s viscosity by measuring the point when the torque starts rotating the disk or bob at a known speed.
“Cup and bob” viscometers work by determining the exact volume of a sample which is to be trimmed within a test cell. This works only when the torque achieves a certain rotational speed and then it is measured and plotted. There are two classical geometries in “cup and bob” viscometers known as “Couette” or “Searle” systems. In some cases, the rotating cup is preferred, because it reduces the onset of vortices at a very high shear rates. However, the rotating bob is commonly used due to its flexible design for other geometries.
“Cone and plate” viscometers use a narrow-angled cone in close proximity to a flat plate. It allows the shear rate between the geometries to be constant at any given rotational speed. The viscosity can easily be calculated from shear stress from the torque and shear rate from the angular velocity.
Calculating shear rate and shear stress form factors differ for each measuring system. Each measuring system will have an associated “form factors” to covert torque to shear stress and to convert angular velocity to shear rate.
- C1 is shear stress form factors and the shear rate factor is C2.
Shear stress = C1 × torque
Shear rate = C2 × angular velocity / gap
Viscosity = shear stress / shear rate
The following sections show how the form factors are calculated for each measuring system.
Cone and plate
C1 = 3 / 2 × r3
C2 = 1 / θ
where: r = radius of the cone
θ = cone angle in radians
C1 = 3 / 2 × r3
C2 = 3r / 4
where r = radius of the cone
NOTE: The shear stress varies across the radius for a parallel plate. The above formula refers to the 3/4 radius position
C1 = ra2H / 3
C2 = 2ri2ro2 / ra2 (ro2 - ri2)
ra = (ri + ro) / 2
ri = inner radius
ro = outer radius
H = height of cylinder
NOTE: C1 takes the shear stress as that occurring at an average radius position ra.
GAOTek’s viscometers are made up of these features:
- Collects data accurately and effectively
- Gorgeous display of test data with ultra-bright LCD screen
- Able to determine the absolute viscosity of Newtonian and Non-Newtonian liquids (including, but not limited to greases, oil paints, plastics, pharmaceutics, coatings, adhesives, detergents, asphalt, hot sol, paraffin, high polymer, etc.)
- Able display data in real time, and print out measurement data
- Microcomputer technologies for temperature control, data collection, and data process
- High speed rotational spindle efficiently measures viscosity
- Simple interface allows for easier operation
- Effective in various environments
Viscometers have wide and varied applications in the materials science and chemical industries for materials such as oil, asphalt, plastics, wax, paints, coatings, and adhesives. They are also used for food and beverages and personal-care products such as cosmetics, shampoo, and toothpaste.
Viscosity is a very useful indirect measure of material properties including molecular weight and density, both of which affect flow behavior. Viscometers can therefore be used to monitor batch consistency and quality control.
Some examples of these applications include:
· Measuring the flow of engine oil under different temperature conditions
· Analyzing the flow properties of milk to design suitable piping systems
· Checking the viscosity of jams and syrups to ensure batch consistency
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Brookfield Viscometer with high measurement sensitivityID: GT00WM00ZT
Brookfield Viscometer with high viscosity resistance rangeID: GT00WM00ZS
Rotation Viscometer with 7 Spindle RangeID: GT00WM00ZO
Rotation Viscometer with Accurately Data CollectionID: GT00WM00ZP
Rotation Viscometer with Good Measurement Error PercentageID: GT00WM00ZM
Rotational Viscometer (High Sensitivity and Reliability)ID: GT00WM00ZN
Rotational Viscometer with Good Measurement RangeID: GT00WM00ZQ
Rotational Viscometer with Good Temperature Control AccuracyID: GT00WM00ZW
Rotational Viscometer with High-Measurement RangeID: GT00WM00ZZ
Rotational Viscometer with High-Measuring AccuracyID: GT00WM00ZY
Rotational Viscometer with Variable Measurement RangeID: GT00WM00ZV
Rotational Viscometer with Variable Rotation SpeedID: GT00WM00ZX
Rotational Viscometer with Wide Range of Dynamic ViscosityID: GT00WM00ZR
Viscometer with High Accuracy (Anti-Interference Ability)ID: GT00WM00ZL