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How does a kinematic viscometer work ?

Views:2     Author:Site Editor     Publish Time: 2020-05-28      Origin:Site

The kinematic viscometer plays an important role in measuring the viscosity and flow characteristics of a liquid, but do you know how it works? What areas can the kinematic viscosity measuring instrument be applied to? What factors affect the measurement of the Kinematic viscosity meter?

Brookfield Rotational Viscometer with bigger measuring range


  • How does the kinematic viscometer work?

  • Application of kinematic viscometer

  • Precautions for purchasing a kinematic viscometer

  • Kinematic viscometer cleaning and maintenance


How does the kinematic viscometer work?

Kinematic viscosity is a measure of the internal flow resistance of a fluid under the action of gravity. It is determined by measuring the time in seconds, which is the time required for a fixed volume of fluid to flow through a known distance in a capillary within the calibration viscometer by gravity at a tightly controlled temperature. This value is converted to a standard unit, such as tic (ist) (cSt) or square millimeters per second. Viscosity reports are only valid when the temperature at which the test is being performed is also reported, for example 23 cSt at 40 degrees Celsius.


None of the tests used for waste oil analysis provided better test repeatability or consistency than viscosity. Again, for effective component lubrication, there is nothing more important than the viscosity of the base oil. However, the viscosity is more visible than the naked eye can see. Viscosity can be measured and reported as dynamic (absolute) viscosity or kinematic viscosity. The two are easy to confuse, but there are big differences. The most commonly used oil analysis laboratory measures and reports kinematic viscosity. In contrast, most on-site Kinematic viscosity meters measure dynamic viscosity, but can be programmed to estimate and report kinematic viscosity, so the reported viscosity measurements reflect the kinematics reported by most laboratory and lubricant suppliers. .


Application of kinematic viscometer

A kinematic viscometer measures the viscosity and flow characteristics of a fluid. Viscosity is produced by the internal friction of a fluid and is defined as the resistance of the liquid to flow or shear stress. kinematic viscosity measuring instrument viscometers have a wide variety of applications in materials science and the chemical industry for materials such as oils, asphalts, plastics, waxes, paints, coatings and adhesives. They are also used in food and beverage and personal care products such as cosmetics, shampoos and toothpaste.


It is important to measure viscosity when considering the process conditions of materials that need to be pumped or piped. Viscosity also affects impregnation and coating properties, which is particularly relevant to paints and inks. Viscosity is a very useful method of indirectly measuring material properties, including molecular weight and density, both of which affect flow properties. Therefore, a kinematic viscometer can be used to monitor batch consistency and quality control.


Since the change in viscosity reflects the change in molecular weight, a kinematic viscometer is used to characterize the plastic. They are particularly useful in polymer synthesis because flow rates can be used to determine changes in polymer length through different processes. In many industrially useful situations, the viscosity decreases as the enzyme activity increases. Viscometers are used to determine the activity of enzymes such as cellulases, proteases, amylases and pectinases.


Precautions for purchasing a kinematic viscometer

Choosing a kinematic viscometer is a complex process that will depend on the sample type, viscosity, opacity, available volume of the sample, the required flux, and the level of automation required. At least the following factors should be considered:


Viscosity range. The viscosity is in Pascal seconds (Pa·s), in other words, the amount of pressure required to reach a given flow rate. Viscosity is usually expressed in centipoise (cP), which is the unit used by the standard agency ASTM International; 1 cP is equal to 1 mPa·s. The dynamic viscosity of water at 20 ° C was 1.002 cP. Kinematic viscosity is the ratio of dynamic viscosity to density; the unit of measure is Stoke (St).


Accuracy. The accuracy of a Kinematic viscosity meter depends not only on the engineering of the instrument itself, but also on how to precisely control the temperature. Repeated viscosity measurements are typically performed and averaged to achieve results with associated accuracy. Viscosity standards are used to check the accuracy of a kinematic viscometer and are important for verifying compliance with industry quality systems. Check that the manufacturer provides the standard that is right for your application.


Temperature control. The viscosity of most materials decreases with increasing temperature. Materials such as motor oil are subject to conventional temperature changes during use and therefore require viscosity measurements at different temperatures. Therefore, accurate temperature control of the kinematic viscosity measuring instrument is very important.


Sample volume and trace amount. The amount of sample is very important for biological samples, especially in clinical laboratories. The simplest Kinematic viscosity meter can only be measured once at a time, but for continuous measurements or measurements at different temperatures, it is useful to use an automated system.


Viscometer size. The size of the kinematic viscometer varies depending on the various viscosities that can be tested. It is recommended that the kinematic viscometer take at least 200 seconds (for manual measurements using a stopwatch) to allow the test fluid to flow from one marker point to another to avoid human error.


kinematic viscometer cleaning and maintenance

Another crucial kinematic viscometer test factor is the quality of the in-vitro rinse between the two measurements. Typically, the cleaning, rinsing and drying stages are carried out using a variety of residual solvents. The built-in cleaning system ensures cleanliness in laboratories that run samples continuously on large-volume kinematic viscometers. However, a visual inspection is still required to determine if a second rinse cycle is required, especially for used oil. Other important factors that may affect viscosity measurement include the timing and accuracy of the timing device, proper sample handling, and in-depth and continuous quality control.


Viscosity measurements have been developed over the years using a variety of styles and methods. Thanks to ASTM and the International Organization for Standardization (ISO), viscometer test methods, procedures, calibration, cleaning and other factors have also been developed to ensure accuracy and consistency between different viscometers. After all, viscosity is the most important physical property of a base oil. Efforts to make viscosity measurements through careful methods and stringent standards can be equated with more reliable mechanical lubrication and ultimately equivalent to longer lasting machinery.


Before you make a liquid viscosity measurement, make sure that the kinematic viscometer you have selected has passed the required ASTM or ISO industry standard certification.If you are looking for a reasonably priced high quality kinematic viscometer, NANJING T-BOTA SCIETECH INSTRUMENTS&EQUIPMENT CO.,LTD can provide you with the best products.

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