Rheometer, what is it and how much does it cost?

November 2, 2021

The rheometer is the device that measures rheological properties in materials . But, you might be wondering. What is rheology? It is a study that measures the flow and deformation of matter. And it describes the relationship between deformation, time and force.

What is a rheometer?

rheometer also measures the viscosity and elasticity of materials whose properties are non-Newtonian . This type of materials are those in which its viscosity varies according to the temperature and if you apply pressure it becomes a solid material.

To measure viscosity we also have the viscometer , but the rheometer is a much more complete device, since the former can only measure viscosity in liquids, and under fairly limited conditions. However the rheometer can do it in a wide variety of conditions.

What are the properties that the rheometer can measure?

The properties that are most important in matter and that the rheometer can measure are the following:
✅viscoelectricity
✅thixotropy
✅yield flow
✅extensional viscosity
✅behavior during stress relaxation
✅yield stress
✅melt fractures
✅extrusion swelling

Viscoelasticidad

Viscoelasticity is one of the fundamental characteristics for the human body. IF we did not have this property, we would not be able to do absolutely any of the activities that we carry out on a daily basis without suffering damage. The viscoelasticity or the viscoelastic properties   of a body depend on the specific structure that we are going to put under analysis.

Thixotropy

Thixotropy is the property of fluids called non-Newtonians and they are those that show a change in their viscosity over time. When it is subjected to this type of fluids to make shear stresses (shear or shear stress), it is when its viscosity decreases much more.

Yield flow

When we speak of yield or creep we refer to the irrecoverable deformation of matter after an effort. It corresponds to its elastic deformation, and the deformation is irreversible.

Extensional viscosity

It is the measure of resistance in relation to extension forces. When a material begins to flow from a large channel to a small or very small inlet, pressure loss occurs and this is due to extensional reasons.

Behavior during stress relaxation

The behavior of matter is studied while it enters a state of “relaxation” after having undergone the stress of having been put under great effort.

Yield stress

The yield strength or yield stress of a material is defined as the stress that exists in said material, when it is subjected to a compression test or a tensile test, at the exact moment in which the yield or the yield begins. deformation of the same.

Melt fracture

It is about the breaking of the perfect lines of the molten flow. Also called elastic turbulence.

Extrusion swelling

Extrusion is a mechanical industrial process, where a molding action is carried out, by continuous flow, by pressure and push. The material is passed through a mold to give it the desired shape.

How does the rheometer work?

Matter is forced to come out under pressure through a barrel, but always with the determined dimensions. The pressure drop in the barrel or die is then measured, providing flow pressure data, velocity data and the liquid from which the viscosity of the same is calculated. The shear rate and temperature are controlled to simulate the desired environment.

The rheometer has its origins in the polymer industry (plastic), and the truth is that it is very useful for measuring the viscosity of slurries and suspensions. But in addition to polymers, rheometry allows the exploration of materials in other industries such as: Food, ceramic mud, coatings, paints and inks.

The rheometer is capable of applying very high forces on the matter . This is what allows us to explore the behavior at shear rates much higher than those applied with rotational rheometry.

The performance shown by the material against the shear rate is extremely important in various industrial processes (extrusion and pulverization) .

For almost all applications, the sample size required to perform rheometry will be approximately one liter.

Why is the Rheometer important for the industry?

The rheometer measures the same magnitudes always . With this laboratory instrument, the behavior of various materials in fluidity and deformation can be analyzed and determined.

The rheometer has systems that can determine the exact conversion in magnitudes . In many materials it is essential to determine where the exact yield point is. This is a very important value that different industries must know, so that all the products they manufacture have the same quality.

Different types Rheometers

We find two types of rheometers and the differences of both are the operation.

Capillary rheometer

As we could see above, the capillary rheometer originates from the polymer industry. With this type of rheometer, a higher force can be applied to the matter, which makes it possible to evaluate the behavior of the substance or substances, taking them to very high limits.

Rotational rheometer

This is a versatile device that can be configured for different rheological methods, in order to know the performance and structure of some substances.

The rotational rheometer provides immediate and accurate results. This type of rheometer is an avant-garde instrument, with the latest technology. And these qualities give you the ability to generate and interpret data that is truly relevant to the manufacturer and the industry.

The substances that are measured with this type of rheometer are varied, but they will always be those in which their liquid structure is weak. Such as creams, gels, pastes, etc.

Final conclusion

Without a doubt, the rheometer constitutes one of the most important instruments in the industrial laboratory . Without it, manufacturers could not develop quality products, and what is more important, products that correspond to the same brand or industry would not have the same quality.

Dr. Loony Davis5
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Born and raised in Brussels in an English family, I have always lived in a multicultural environment. After several work experiences in marketing and communication, I came to Smart Water Magazine, which I describe as the most exciting challenge of my career.
I am a person with great restlessness and curiosity to learn, discover what I do not know, as well as reinvent myself daily, someone who is curious about life and wants to know. I enjoy sharing knowledge.
This is my personal project but I also collaborate in other blogs, it is the case, the most important web on water currently exists in the US, if you are interested you can read my articles here.

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