5 Top Tips for Mixing Low Viscosity Products

May 15, 2024

Mixing low viscosity products – including free dissolving powders into liquid – presents a unique set of challenges, primarily due to these products’ tendency to flow more freely, making it difficult to achieve uniform dispersion.

The main risk lies in inconsistent product quality, which can lead to customer dissatisfaction, product rejection, and ultimately, loss of business. Improper mixing can result in variations in product composition, leading to performance issues or compromised functionality. Moreover, inadequate mixing may also cause difficulties in meeting regulatory standards or quality control requirements, exposing the business to potential legal or financial consequences. Effective management of low viscosity mixing is thus crucial for maintaining product integrity, meeting customer expectations, and safeguarding the reputation and profitability of the business.

 

What are Low Viscosity Liquid Products?

Typically, in the context of mixing, low viscosity products are up to 2,000cP. Examples include…

• Vitamin mixes, Tablet coatings and other pharmaceuticals
• Food brines, Beverage concentrates and intermediate stages of food production
• Low viscosity adhesives
• Liquid soaps and detergents

 

At Pharma Hygiene Products, our Engineering Team has combined experience of over 40 years in the industry.

We often recommend a Propeller Mixer, which is well suited to mixing low viscosity liquids.

 

What is a Propeller Mixer?

Typically 3 blade, sometimes 4 blade in design, this type of mixer looks like a marine boat propeller! It is typically mounted off centre and at a slight angle within your vessel, to improve the quality of mixing.

The Propeller Mixer works by achieving a vortex. For example, if your production team are mixing a vitamin powder into water to create a supplement, they would add the powder into the vortex. This then passes through the propeller, and the vast majority of mixing is achieved in the first pass. This is a very time-efficient way of achieving a consistent mix, and also prevents clumping of potential lumps of powder. The mixture is then recirculated around the vessel vertically, so your product would travel down through the propeller, then up the side of the vessel, then back down into the propeller, and so on.

 

So how can you ensure you achieve the most resource-efficient mixing of your low viscosity product, using a Propeller Mixer?

In short, what should your production team be considering?

 

Our Top 5 Recommendations Are:

1. Choose the Right Speed: Start at a low speed to prevent splashing and gradually increase to the optimum speed for your product. Too high a speed can create air bubbles and affect viscosity.
2. Optimize Blade Design: Use a propeller blade suitable for low viscosity mixing, typically with a higher pitch angle and more blades. This helps create efficient circulation and minimizes vortex formation.
3. Maintain Consistent Depth: Keep the propeller submerged at a consistent depth throughout the mixing process to ensure uniform blending. Adjust the mixer height if necessary to maintain this depth.
4. Consider Mixing Time: Avoid over-mixing, as it can lead to unnecessary shear and potentially degrade the product. Follow recommended mixing times provided by the product specifications or conduct tests to determine optimal mixing duration.
5. Temperature Control: Monitor and control the temperature of both the product and the mixing environment, as temperature variations can significantly impact viscosity and mixing efficiency. Use cooling or heating systems as needed to maintain desired conditions. Pharma Hygiene Products can also create a Water Jacket for your vessel, for heating, cooling and insulation.

 

Propeller Mixers can also be used to mix oil-to-oil and liquid-to-liquid, which won’t separate out like oil-to-water would. For oil-to-water mixing, we recommend using a High Shear Mixer, due to its ability to break down the oil droplets into smaller sizes, creating a stable emulsion.

Take advantage of our experienced team; we can advise the most cost-effective solution for your application.

+44(0)1444 472300     info@adelphi.uk.com

 

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