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Home. Viscosity Systems. Density Systems. RMI

Types of measurement:

There are two main categories of viscosity measurement:

Behavioural measurements

Behavioural are those where it is the viscosity at the process temperature that is required. These are among the simplest of measurements to resolve though even so, special care is required to select the right instrument and to design a suitable installation.

These measurements relate to the behaviour of the fluid when it flows, is sprayed, atomised or when coating.

Most viscometers available and successful are successful in behavioural measurements.

Analytical measurements

Analytical are those where it is the viscosity at one or more reference temperatures that are required, irrespective of the process temperatures. Historically, these are among the most difficult measurements to make due to the sensitivity of viscosity to a range of parameters other than the parameter of interest.

These measurements relate to the quality of the fluid.

Analytical Measurement Methods:

There are necessarily several different ways to make an analytical measurements.

Direct measurement:

The sample stream is temperature conditioned such that the temperature at which viscosity is measured is the reference temperature.

Indirect measurement:

the viscosity is measured at the process temperature and calculation is used to determine the viscosity at one or more reference temperatures.


The Digital Viscometer

The flexibility and capability of modern viscometers is such that a range of solutions are now available such that it is possible to design systems with regard to the specific application objectives and process conditions.

RMI Systems:

RMI can provide systems for both behavioural and analytical measurements.

For analytical measurements the options are:

Indirect measurement by:

The systems described illustrate the basic principals at work.

The Indirect Measurement Systems for hydrocarbons are based on the temperature Vs. viscosity relationship given in ASTM D341.

An alternative “matrix” method is available for other fluids where the temperature Vs. viscosity relationship is not suitably quantified.

Direct methods are independent of any temperature Vs viscosity relationships.

Different applications require different solutions. Razaghi Meyer will help you find the right solution for your application.

The solution will take account of a variety of application objectives beyond simply obtaining a good measurement; for example, the needs of operators and maintenance are also considered.

Follow the drop down menu links to discover more about the methods available.


Viscosity has proven to be one of the most difficult of process measurements to make well. RMI has the knowledge and skill to make viscosity measurement a success for you.

Viscosity; the resistance of a fluid to flow under the influence of an applied force, is an extremely valuable measurement to the process engineer. This is because viscosity is far more sensitive to changes in quality that most any other parameters.

Process Viscosity Analyser Systems: