A viscometer is an apparatus intended to measure the Viscosité fluids. There exist two types of viscometers: viscometers of process and viscometers of laboratory.

Vibrating industrial viscometer

Principle of operation

The active part of the viscometer is a vibrating stem animated by a constant power supply. The amplitude of the vibration varies according to the viscosity of the fluid in which the stem is immersed. These viscometers of process are really revolutionists indeed not having a wearing part, they do not require any maintenance. Moreover certain configurations of vibrating viscometers can function under very difficult industrial conditions: explosive zone, high pressure 300 bar, high temperature 300°C, high viscosity 1.000.000 mPa.s. Contrary to the rotary viscometers, the viscometers of the vibrating type are best adapted for measurements of industrial viscosity because they function athigh rate of shearing and can measure fluids very viscous, plugging agents and fibrous.

Principal applications

• Control of the reactions of Polymerization,

• Control of the viscosity of the Ink S in Printing works,
• Control of Combustion of heavy Fuel,
• Control of texture in agribusiness industry,
• Quality control of any fluid.

Capillary viscometer

Measure time of flow of the product to deduce its viscosity from it.

Rotational viscometer of laboratory

The rotational viscometers measure the couple necessary to make turn a stem in immersion in a liquid. The stem is rotated by an engine while passing by a gauged spring. Resistance to the flow will increase according to the size of the stem and/or the number of revolutions. Some are with measurement bidirectional with a variable speed control. This type of viscometer is not adapted to industry. Indeed, because of the presence of an engine and according to the frequency of use, the measurement of viscosity can diverge rather quickly and of the regular re-calliperings are necessary. Moreover, with these systems, it is impossible to measure fluids of very high viscosity, products plugging agents, or of the fibrous products.

Another type of rotational viscometer is the viscometer of Maurice Couette: it is composed of two concentric cylinders, the interior cylinder being fixed and the external cylinder in rotation driven by an engine. The measurement of the couple necessary to prevent the rotation of the interior cylinder under the effect of the force of viscosity of the fluid contained between the two cylinders makes it possible to go back to the value of the viscosity of the fluid. The flow between the two cylinders is a flow of Feather bed.