Difference Between Ubbelohde Viscometer and Brookfield Viscometer

Difference Between Ubbelohde Viscometer and Brookfield Viscometer

Abstract：Introducing of Ubbelohde viscometer and Brookfield Viscometer. Concept, difference and advantages of ubbelohde viscometer and Brookfield viscometer.

Brief introduction of Ubbelohde viscometer：

When the fluid is flowing by external force, there is a tangential internal friction between the flowing liquid layers, and if the liquid is to pass through the tube, a portion of the work must be consumed to overcome the resistance of the flow. When the flow rate is low, the liquid in the pipe is advanced in a straight line parallel to the pipe wall. The liquid closest to the pipe wall is actually stationary, and the farther the distance from the tube wall is, the greater the flow rate is. The tangential force f between the flow layers is proportional to the contact area A between the two layers and the velocity difference Δv, and is inversely proportional to the distance Δx between the two layers: where η is the proportional coefficient, called the viscosity coefficient of the liquid, Referred to as viscosity.

The molar mass of the polymer not only reflects the size of the polymer molecule, but also directly related to its physical properties, is an important basic parameter. Unlike conventional inorganic or low molecular organic matter, the polymer is mostly macromolecular mixture of different molar mass, so the measured molar mass of polymer is usually a statistical average. 

Brief introduction of Brookfield Viscometer:

       Brookfield Engineering is an engineering and manufacturing company with headquarters in Middleboro, Massachusetts. Its product line includes laboratory viscometers, rheometers, texture analyzers, and powder flow testers as well as in-line process instrumentation. These instruments are used by research, design, and process control departments. It was suspected of causing one of Massachusetts' most unusual and serious residential toxic waste contamination problems, and settled the claim by paying relocation and cleanup costs without admitting responsibility.       

Classical Brookfield viscometers employ the principle of rotational viscometry - the torque required to turn an object, such as a spindle, in a fluid indicates the viscosity of the fluid. Torque is applied through a calibrated spring to a disk or bob spindle immersed in test fluid and the spring deflection measures the viscous drag of the fluid against the spindle. The amount of viscous drag is proportional to the amount of torque required to rotate the spindle, and thus to the viscosity of a Newtonian fluid.In the case of non-Newtonian fluids, Brookfield viscosities measured under the same conditions (model, spindle, speed, temperature, time of test, container, and any other sample preparation procedures that may affect the behavior of the fluid) can be compared. When developing a new test method, trial and error is often necessary in order to determine the proper spindle and speeds. Successful test methods will deliver a % torque reading between 10 and 100. The rheologicalbehavior of the test fluid can be observed using the same spindle at different speeds, but because the geometry of the fluid around a rotating bob or disk spindle in a large container does not allow a single shear rate to be assigned, proper rheometry is not feasible using this setup.

Apart from its rotating bob viscometers, Brookfield now also produces defined-geometry rheometers which allow complete rheological analysis of fluids.

Difference Between Ubbelohde Viscometer and Brookfield Viscometer

1. Ubbelohde Viscometer：Cheap, suitable for relative measurement, Uptel viscometer itself can not control temperature, with precision thermostat can be accurate measurement of viscosity, in addition to the Ubbelohde viscometer installed in the automatic viscosity test equipment, you can achieve Ubbel's viscosity Automatic measurement, directly to the intrinsic viscosity, than the viscosity, relative viscosity, viscosity, viscosity average molecular weight and other needs of the measurement results.
2. Brookfield Viscometer：Have adopted the well-known viscosity measurement principle, which absorbs the viscosity value by the continuous rotation of the rotor immersed in the liquid to be measured. The torque is proportional to the resistance of the rotor immersed in the sample by sticky dragging, proportion.

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