They will reach out for a recommendation for you. Thanks for your inquiry. Suggest us a suitable instrument for measuring viscosity. Save my name, email, and website in this browser for the next time I comment. Notify me of follow-up comments by email. Notify me of new posts by email. This site uses Akismet to reduce spam. Learn how your comment data is processed. Here are six types of viscosity measurement devices to consider: Falling ball viscometers A falling ball viscometer measures the viscosity of fluids and some units can also measure the viscosity of gases.
Viscosity cups The various forms of viscosity cups use gravity to allow a fluid to flow through an orifice located at the bottom in a precise amount, which can be measured over time to calculate a viscosity value. Consistometers The consistometer is a metal trough with graduations which measures viscous materials as they flow at an incline under their own weight. Glass capillary viscometers A glass capillary viscometer is used in conjunction with test methods which conform to a particular ASTM.
Rotational viscometers A rotational viscometer accommodates a wide range well into millions of centipoise and is considered the most versatile type of viscometer.
Home Our solutions Our solutions for material characterization. Particle size. Dispersibility - Redispersion. Bulk rheology. Coating analysis. Microstructure thermal analysis. Flow rheology by microfluidics. Product range. Microfluidics by optical imaging. The capillary viscometer is one of the earliest known methods to determine fluid viscosity. This method measures the time taken for a defined volume of fluid to flow through a U-shaped capillary tube of known diameter and length.
The tube usually has two marks an upper and lower mark that are used as a measurement reference. The time it takes for the fluid to flow past these marks is proportional to the kinematic viscosity; hence the value of viscosity can be determined using standard formulas. The falling sphere viscometer is used to determine the dynamic viscosity of a transparent Newtonian fluid. The concept involves measuring the time it takes for a sphere of known density to fall through a sample-filled tube under gravity.
The tube is usually mounted on an apparatus that can quickly rotate degrees to allow repeat testing. The average time of three tests is recorded and used in a conversion formula to determine the viscosity of the sample. A consistometer is an apparatus that is comprised of a metal trough with a small section barred behind a spring-loaded gate. The sample to be tested is first placed behind the spring-loaded gate.
Next, the gate is lifted, allowing the sample to flow freely under its own weight. The distance that the liquid flows in a specific time is measured via gradations of the apparatus. The consistometer itself does not measure viscosity values directly — it instead allows users to develop their own standards specific to the products being tested.
This method is more popular in the food industry and is typically used to measure the viscosity of products such as ketchup and mayonnaise. Viscosity is an important fluid property that is essential for a number of different products in various industries.
Dynamic and kinematic viscosities describe different properties and can produce very different results when testing fluids. It is therefore important that the difference between the two types of viscosities be understood and the appropriate test selected for the given sample. Written by Krystal Nanan Civil Engineer. Subscribe to our newsletter to get expert advice and top insights on corrosion science, mitigation and prevention. Schematic representation of the layout of typical controlled-stress and controlled-strain viscometers.
A number of supposedly simple geometries are used to measure viscosity, but although the geometry seems simple, the flow field is not. The best example of this is the flow cup, where liquids runs out from a cup through a given nozzle under the action of gravity. In this case we have shear and extensional flow, plus inertia and time effects present simultaneously, and it is virtually impossible to extract only the shear viscosity as a function of shear stress which is of interest.
In all geometries inertia effects can be important. These manifest themselves in a number of ways depending on the particular geometry. For instance, in circularly symmetric geometries such as the cone and plate, parallel plate and concentric cylinders, it is possible to set up vortex-like secondary flows that absorb extra energy compared with the primary flow and hence display a higher-than-expected viscosity if not taken into account see below. Other artifacts can also be present, see Figure 4.
Even when end effects are eliminated in a well-made viscometer, there can still be wall effects giving real or apparent slip effects. This usually gives a lower-than-expected viscosity see below. These can be overcome by roughening the surface of the viscometer geometries in contact with the liquid being measured. Figure 5. Typical surface profiles to overcome slip at the walls of viscometers.
Viscometers require careful calibration.
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