What products are involved?

Rheonics SRV viscometer, SRD density-viscosity meter, DVP gas density-viscosity meter, and DVM HPHT density-viscosity meter.

What is the purpose of this article?

The article emphasizes the importance of real-time viscosity measurement in optimizing processes, preventing equipment failures, and ensuring product consistency. It also explores viscosity's role across industries and compares offline, atline, online, and inline methods to help choose the best approach.

In today's fast-paced industries, ensuring consistent product quality and operational efficiency requires precise fluid monitoring. Viscosity, often overlooked in daily life, plays a critical role in various applications, from manufacturing and lubrication to food processing and medical treatments. 

The article emphasizes the importance of real-time viscosity measurement in optimizing processes, preventing equipment failures, and ensuring product consistency. It also explores viscosity's role across industries and compares offline, atline, online, and inline methods to help choose the best approach.

Figure 1. Viscosity meter SME-TRD-SRV.

1. What is viscosity?

A fluid’s viscosity is a measure of its resistance to flow. It describes the internal friction of a moving fluid. Viscous fluids resist motion because their molecular makeup creates a lot of internal friction. Fluids with low viscosity flow easily because their molecular makeup creates little friction when they are in motion.

On a molecular level, viscosity is caused by the interactions between different molecules in a fluid. This can also be considered to be friction between the molecules. Just like in the case of friction between moving solids, viscosity will determine the energy required to make a fluid flow.

The best way to visualize this is through an example. Consider a cup made of Styrofoam with a hole at the bottom. I notice that the cup drains very slowly when we pour honey into it. This is because honey’s viscosity is relatively high when compared to other liquids. When we fill the same cup with water, for example, the water will drain much more quickly. A fluid with a low viscosity is said to be “thin,” while a high-viscosity fluid is said to be “thick.” It is easier to move through a low-viscosity fluid (like water) than a high-viscosity fluid (like honey).

2. Where is the viscosity useful?

In many different fields, viscosity can actually be quite useful, even though it seems to be of minor importance in daily life. For instance:

• Lubrication in vehicles, When you put oil in your car or truck, you should consider its viscosity. It’s because viscosity affects friction, which affects heat. Furthermore, viscosity affects both the rate of oil consumption and the ease with which your vehicle starts in hot and cold conditions. The viscosity of some oils remains the same as they heat and cold, while others become thinner as they heat, causing problems as you operate your car during a hot summer day.
• In the preparation and serving of food, viscosity plays a significant role. Many cooking oils become much more viscous with cooling, while others may not change viscosity at all. As fat is viscous when heated, it becomes solid when chilled. The viscosity of sauces, soups, and stews is also important in different cuisines. When thinned out, a thick potato and leek soup becomes French vichyssoise. Honey, for instance, is quite viscous and can change the “mouth feel” of certain foods.
• The equipment in manufacturing needs to be properly lubricated to operate smoothly. Pipelines can be jammed and clogged by viscous lubricants. Thin lubricants provide insufficient protection for moving parts.
• When fluids are injected intravenously, viscosity can be crucial. A major concern involves blood viscosity: blood that is too viscous can form internal clots, while blood that is too thin will not clot, causing dangerous blood loss and even death.

By implementing real-time viscosity measurement, industries can improve process efficiency, reduce waste, and ensure product reliability. This guide provides an in-depth comparison of different viscosity monitoring methods to help select the most suitable solution for your needs.

3. Exploring process monitoring methods

When optimizing production, accurate and precise measurements with good repeatability and reproducibility are essential for maintaining consistency and efficiency. Each measurement approach—inline, online, atline, and offline—varies in accuracy, automation, and frequency, impacting data reliability and decision-making. Understanding these differences helps industries select the most effective strategy for quality control and process optimization, ensuring reliable data, reduced errors, and consistent measurement performance across diverse applications.

Figure 3. Process monitoring methods

4. Advantages of Rheonics inline viscometers and density meters to ensure tight process control

• Rheonics builds truly inline process instruments. Ensuring that the sensor´s reproducibility and repeatability of measurements are exceptional, generally better than 0.1-1% for the SRV viscosity meter. 

• Rheonics runs calibration standards with NIST traceable viscosity and density standards at different times under similar conditions, ensuring each probe is evaluated for reliable and accurate measurements. 
• Consistency of results is essential to the success of customers' quality control programs, as it ensures that all measurements are reliable and accurate. The repeatability of measurement also allows for the easy comparison of results across different batches. 
• Furthermore, the repeatability of measurement allows for quick and easy troubleshooting when a process fails to meet expectations. 
• Based on Rheonics' proven gated phase-locked loop technology, the electronics unit offers stable, repeatable, and high-accuracy readings over the full range of specified temperatures and fluid properties.
• SRV and SRD are operator-independent and measured in real-time.
• Temperature effects can be compensated in real-time.

5. Viscosity Inline monitoring vs Viscosity offline monitoring

Customer applications of the Rheonics SRV sensor for measuring viscosity in various systems have become a standard and widely used method for ensuring consistency.

Traditionally, customers have relied on lab-based viscometers to measure viscosity, generating large volumes of data. However, lab instruments have limitations such as the need for manual sampling, potential human error, and delays in obtaining results, which can hinder real-time process adjustments. This data is now being leveraged to integrate viscosity measurement directly into process lines using the SRV sensor, enabling more efficient and precise monitoring.