Viscometer

CONTENTS• Viscosity • Viscometer• Types of viscometer

Viscosity• The device used for measurement of viscosity is known

as viscometer .• The viscosity of a fluid is a measure of its resistance to gradual

deformation by shear stress or tensile stress.• The units of viscosity is poise and centipoise .• specific viscosity is the ratio of the viscosity of fluid to the

viscosity of water at 20 degree Celsius. Since the water has a viscosity of 1 cp at 20 degree Celsius.

• Kinematic viscosity is defined as ratio of dynamic viscosity to the density of the fluid.

Viscometer

What Is Viscometer?

A Viscometer is an instrument used to measure the viscosity of a fluid.It is also known as Viscosimeter.For liquids with viscosities which vary with flow conditions, an instrument called a rheometer is used. Viscometers only measure under one flow condition.

Types of Viscometer

• Rotational Viscometer• Vibrational Viscometer• Oscillation Viscometer• Falling Piston Viscometers• Falling Sphere Viscometer• Saybolt Viscometer

Rotational Viscometer

• Rotational viscometer gathers data on a material’s viscosity behavior under different conditions.

• Rotational viscometers can be used for the accurate measurement of viscosity for both Newtonian and non-Newtonian fluids.

Fig: Rotational Viscometer

Vibrational Viscometer

• A Vibrational Viscometer is used for continuous direct measurement of viscosity in pipes and/or tanks.

• Vibratory Viscometers are better suited to measure non-newtonian liquids.

Fig: Vibrational Viscometer

Oscillation Viscometer

• The oscillating piston viscometer technology has been adapted for small sample viscosity and micro-sample viscosity testing in laboratory applications.

• It has also been adapted to measure high pressure viscosity and high temperature viscosity measurements in both laboratory and process environments.

Fig: Oscillation Viscometer

Falling Piston Viscometers

•The principle of viscosity measurement in this rugged and sensitive industrial device is based on a piston and cylinder assembly.

•The piston is periodically raised by an air lifting mechanism, drawing the material being measured down through the clearance (gap) between the piston and the wall of the cylinder into the space which is formed below the piston as it is raised.

Fig: Falling Piston Viscometer

Falling Sphere Viscometer

• The falling ball viscometer is based on Stokes’ Law.• This type of viscometer consists of a circular cylinder

filled by the liquid under investigation.• A standard ball is allowed to fall down this tube over a

calibrated distance of 100 mm.• Stokes' law can be used to calculate the viscosity of the fluid.

A series of steel ball bearings of different diameter are normally used in the classic experiment to improve the accuracy of the calculation.

Fig:Falling Sphere Viscometer

Saybolt Viscometer

• A device used to measure the viscosity of a fluid. The saybolt viscometer controls the heat of the fluid and the viscosity is the time is takes the fluid to fill a container.

• Efflux cup viscometers are most commonly used for fieldwork to measure the viscosity of oils, syrups, varnish, paints and Bitumen emulsions.

• The saybolt viscometer, one of the efflux cup viscometers is the standard instrument for testing petroleum products.

•  The testing procedure is quite similar to the capillary-tube viscometers

Prepared By:• Darshan Talsaniya - 140570119108• Jagrut Joshi - 140570119044• Jatin Mandaliya - 140570119065• Nevil Gambhava - 140570119029

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