Knowledge Article
How Viscosity Affects Your Flow: Stability, Performance and Control in Process Environments
In many manufacturing processes, it is not just the amount of fluid that matters, but how it behaves. Viscosity in process industries is one of the most important factors affecting flow, quality and overall reliability. In the chemical, food, biotechnology and paints and coatings industries, even small changes in the viscosity of a fluid can affect the flow, quality and stability of the process.
When viscosity increases or varies, the whole premise of the process changes: pressure drops rise, pumps are loaded more heavily, degree of filling changes, and filtration can become significantly more demanding. Therefore, understanding viscosity in the process industry is one of the most crucial areas when working with flow systems
Viscosity in the process industry - what is it and how does it work in a flow system?
Viscosity describes the internal friction of a liquid, i.e. the force required to make the liquid move. In practice, this means that:
- thinner media (e.g. water, solvents) flow easily
- viscous media (e.g. syrups, oils, polymers) require much more force
For you in industry, this means that viscosity is directly linked to:
- pressure drop
- the efficiency of the pump
- energy needs
- temperature sensitivity
- filtration efficiency
- the stability of the whole process
Viscosity therefore determines how the medium moves through pipes, pumps and filters, not just how much passes through.
Five reasons why viscosity is a crucial factor in your flow
The impact of viscosity on processes is most evident in the following areas:
1. pressure drop and resistance in the pipe system
As the liquid thickens, the resistance increases significantly. This leads to:
- risk of flow falling below process requirements
- higher pressure drop across pipes and valves
- overloading of pumps, even at low flows
In practice, this often means that a process that worked smoothly at 25°C becomes problematic at 10°C simply because of increased viscosity.
2. reliability and capacity of the pump at high viscosity in process industry
Just as magnetic drive pumps eliminate shaft seals to increase stability, viscosity is another factor that either helps or hinders operation.
High viscosity often means:
- reduced efficiency
- lower actual flow than the pump curve shows
- higher engine load
- risk of cavitation in case of incorrect dimensioning
The right pump selection for viscous media is therefore crucial for long life and predictable operation.
3. Filtration and filter media lifetime
Viscous media move more slowly through filtration materials. This means:
- higher initial pressure drop
- faster saturation
- greater need for filter area
- requirements for the right pore size and design
Many processes also need tempering to keep viscosity down during filtration.
4. Flow profile, mixing and filling
The flow becomes more sensitive to:
- pipe drawing
- böjar
- valves
- speed
High viscosity results in uneven filling in molds and packages and places higher demands on process control.
5. temperature sensitivity and stability in high viscosity processes
For many media, viscosity is extremely temperature dependent. A small drop in temperature can have:
- the flow to drop
- the pressure drop to rise
- the pump to run heavier
- product time to change
This makes temperature control a key part of the requirements for viscous processes, especially where viscosity in process industry vary over the year or between different batches.
A wide range of solutions for viscous media
At Colly Flowtech, we offer one of the market's widest ranges of components and system solutions for both thin and highly viscous media. All solutions are based on proven materials and technology developed for demanding industrial environments.
The result is systems that reduce risk, provide peace of mind, improve operational safety and simplify everyday life in the plant, whether the medium is thinner than water or thicker than honey.
Want to know more about viscosity in process industry? We are happy to help you analyze how viscosity affects your process and find the right components and dimensioning for a stable and energy-efficient flow.
Get in touch with me (mattias.jansson@colly.se), and we will take it forward together.
This text is written by Mattias Jansson (Mattias.jansson@colly.se), Product Manager Pump at Colly Flowtech.
Frequently asked questions about viscosity in process industries
What is viscosity in the process industry and why is it so important for flow?
Viscosity describes how viscous a fluid is and affects how easily it moves through pipes, valves and filters. It is key because it directly affects flow, pressure drop and reliability.
How does increased viscosity in process industries affect pressure drop and energy demand?
As viscosity increases, resistance in the piping system increases. This results in higher pressure drops across pipes, valves and filters, which in turn requires more pumping power and thus more energy. If the system is not sized for viscous media, the flow can drop below process requirements and pumps can be overloaded.
What type of pump is best for viscous media in process industries?
Positive displacement pumps are usually best for viscous media. Proper sizing is crucial to avoid cavitation and low efficiency.
How are viscosity, temperature and process stability related?
Lower temperatures make liquids more viscous, increasing pressure drop and load on the pump. Stable temperature control provides smoother flow and better process stability.
What can I do if the viscosity varies in my process?
Adjust temperature control, pump sizing and filtration to compensate for changes in viscosity. A process analysis will help you find the most efficient solution.
Do you have any questions?
