Rotational Viscometer
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7May/10Off
Haake VT550 Rotational Viscometer
The Haake VT550 is a rotational viscometer designed
for fast and precise measurement of viscosity and flow behavior
for quality control and has established itself as a state of the art
instrument in quality control.
Product Details
The Haake VT550 is a Searle viscometer. A rotational
speed is preset and the flow resistance of the sample is measured
in other words, the torque maintaining the set speed is proportional
to the viscosity. All final information on the viscosity, shear stress
and the shear rate is calculated from the torque required, the set
speed and the geometry factors of the applied sensor. The results
are displayed digitally and can be printed simultaneously.
For viscosity measurements a total of 60 different rotational speed
steps are available. 50 out of these 60 are factory set; the
remaining 10 are user programmable. The 60 steps cover a wide
range reaching from 0.5 rpm to 800 rpm. The resulting torque is
measured via a non-contact, low displacement sensor which enables
the extended measuring range with perfect signal linearity over the
whole range. The operating temperature can be measured by PT100
probes located either in the sensor used or directly in the test material.
Haake VT550 Applications
Perfect for quality-control investigations as well as routine measurements.
Food : Sauces, Mayonnaise, Mustard, Ketchup, Thickening Agents, Stabilizers, Starch, Pectin
Cosmetic/Pharmaceutical : Creams, Lotions, Shampoos, Toothpastes, Liquid Soaps
Paint : Water-based and Latex Paints, Bonding Agents, Resins
Chemical : Liquid and Paste-like Raw Materials
Haake VT550 Specifications
| Number of Speeds | Continuous |
| Speed Range | 0.5–800rpm |
| Speed Range Stability | ±0.1% |
| Temperature Range | -20° to +100°C |
| Temperature Range Stability | ±0.5% fsd |
| Typical Measuring Time | 1 min. |
| Number of Sensors | 2 cups, 2 rotors |
| Reproducibility | ±1% |
| Voltage/Frequency | 100-230V 50/60Hz |
3May/10Off
Rotational Viscometer Defined
A rotational viscometer uses the concept that the torque it
takes to rotate an object submerged in fluid is functionally
related to the fluid's viscosity. A rotational viscometer takes
precise measurements of the required torque to turn a bob
or disk in fluids at a predetermined speed.
Cup and Bob Rotational Viscometer Diagram
One particular type of rotational viscometer, known as a 'cup
and bob' viscometer, utilizes a known volume of sample fluid
which is, in turn, sheared within a test cell (the cup). The
applied torque for the bob to reach a predefined rotational
speed is measured and plotted to gain the desired viscosity
value. There are two general system types of 'cup and bob'
rotational viscometers, the Couette and the Searle systems.
These two types are differentiated by whether the bob or the
cup is rotated. A rotating test cell (cup) is preferred in certain
situations due to the reduction of Taylor vortices, however, this
type of rotation tends to lose accuracy in the measurement.
Cone and Plate Rotational Viscometer Diagram
A second type of rotational viscometer, dubbed the 'cone and plate'
rotational viscometer utilizes a shallow angled cone which is in bare
contact with a flat plate inside. A small quantity of fluid is sandwiched
between the cone and the plate, the cone is rotated at a steady
angular rate, and the required torque is measured to determine the
viscosity value.