When combining highly viscous materials that wouldn’t typically blend into a uniform substance, or dispersing powders into high-viscosity liquids, selecting the right high-viscosity mixing equipment is essential to the success of your product. Why? With challenging materials like these, achieving uniformity is often difficult, and that uniformity (or lack thereof) can significantly impact the performance, stability, and durability of the resulting product.

Why High Viscosity Mixer Selection Directly Impacts Product Performance

Not all high viscosity mixing applications behave the same, and neither should the equipment used to process them. Choosing the right high viscosity mixer plays a critical role in determining batch uniformity, dispersion quality, cycle time, and overall process repeatability.

Different mixer designs deliver shear energy, material movement, and wetting action in distinct ways. Some models excel at folding and turnover for dense pastes, while others provide higher shear zones needed to properly disperse powders or break down agglomerates. If the mixer’s design does not align with the formulation’s rheology, even well-developed recipes can suffer from inconsistent texture, trapped dry material, temperature variation, or extended mixing times.

The right mixer selection helps ensure:

• Uniform material distribution throughout the batch.
• Consistent wetting and dispersion of powders into high-viscosity liquids.
• Controlled shear delivery without overprocessing sensitive materials.
• Stable temperature profiles during demanding mixing cycles.
• Repeatable results from batch to batch and scale to scale.

Understanding how each mixer configuration influences flow patterns, shear zones, and material turnover is essential before committing to a specific design. The sections below explore how different high viscosity mixer types address these challenges and where each performs best, based on application demands.

Horizontal Mixer: Rugged Efficiency That Gets the Job Done

Hockmeyer’s Horizontal Paste Mixer features triple mixing blades for uniform wetting and fast mixing of even the toughest materials, as well as a specially designed impeller that follows the contours of the tank precisely to help eliminate “dead” spots. Additionally, Hockmeyer’s jacketed tanks can be used to ensure uniform temperature control when producing high-temperature industrial processing applications. These jackets create an excellent temperature transfer for thermal fluid operations, establishing temperature control within the batch, and have the capability of being divided into multi-pass zones to increase process flexibility.

This mixer’s overlapping arms prevent material buildup, while the double rolling action of the blades moves the material against the side of the tank for excellent shear (the relative movement of adjacent layers in a liquid or plastic during flow) and wetting (the interaction between the surface of a liquid and the surface of a solid or another liquid). As a result, the Horizontal Paste Mixer is ideal for everything from adhesives, sealants, and printing inks to polyesters, ceramics, pharmaceuticals, and more. Plus, in addition to durability and efficiency, this mixer requires less power than similarly sized machines since no motion is wasted during the blending process.

HHL-III Triple Shaft Mixer / Disperser: Low Speed and High Speed Blades Work Together to Ensure Uniform Mixtures 

To ensure the proper dispersion of highly viscous materials, Hockmeyer’s multi-shaft mixers have a center-mounted low-speed helical or anchor blades which sweep the mixing vessel wall and one or more high-speed dispersion shafts, which provide shear to disperse or dissolve ingredients. Triple-shaft mixers like the HHL-III are most often used to mix medium– to high-viscosity products and are typically used when making materials such as sealants, caulks, magnetic media slurry, creams, and more.

Wondering why low-speed blades are an essential feature of this mixer? Using low speed to assist in effectively mixing materials may seem counterintuitive, but the low-speed blade feeds the high-speed dispersion blade(s) by blending and folding the mass in the vessel to improve product uniformity, while the patented scrapers provide excellent heat transfer and aid in powder incorporation. 

Another benefit of multi-shaft mixers like the HHL-III Triple Shaft Mixer is their use of bi-directional Teflon scrapers. The scrapers are stacked on top of each other in a continuous row, creating complete coverage of the sidewall and bottom of the tank. Additionally, high-speed dispersers alone have a limited zone of influence in viscous products, so the low-speed blade is necessary to achieve a uniform, well-blended mixture. 

Learn more about HHL-III, our Triple-Shaft Mixer

Mixer / Disperser: Easier Maintenance with Excellent Performance

Like the HHL-III Dual Shaft Mixer/Disperser, the HHL-II utilizes a center-mounted low-speed helical or anchor blade that sweeps the mixing vessel wall to ensure accurate dispersion, and a high-speed dispersion shaft to ensure proper dispersion. Dual shaft mixers, like this one, are most often used to mix medium to very high viscosity products, and are used in the making of printing inks, caulks, hot melt adhesives, lotions, toothpaste, and more. 

One benefit of the Dual Shaft configuration is that it will handle most multi-shaft mixing jobs. Because of its separate mixing shafts, maintenance is easier on a Dual Shaft mixer than on a Concentric Shaft mixer. Plus, like the HHL-III Triple Shaft Mixer, bi-directional teflon scrapers can aid in heat transfer and provide coverage of the entire sidewall and bottom of the tank.

Learn more about HHL-II, our Dual-Shaft Disperser

Additional Areas for Consideration When Selecting a High Viscosity Mixer

Before you decide which high viscosity mixer is right for your needs, there are a few additional factors to consider. First, it’s essential to understand exactly what you’re trying to achieve. Typically, the goal of mixing is to uniformly blend two or more ingredients. That being said, there are a multitude of factors that affect how uniformity is achieved for your specific product, including loading times and techniques, mixing, cleaning, discharge, machine maintenance downtime, power consumption, and the mixer’s design. Before you choose a high viscosity mixer, you’ll need to carefully review the effectiveness of the whole mixing system, not just the mixer’s performance.

Next, think through the economic impacts of your choice. While everyone would love to own the most effective “dream” mixing system, oftentimes that “dream system” may not be the most economical choice. A system’s projected profitability and length of time the product may be in demand must be matched against not only the capital and operating costs of the system, but also the anticipated start-up time required with such a system. Additionally, the equipment’s alternative use and resale value should be considered.

Ultimately, the truth is that there is no one mixer that can satisfy all mixing needs. While viscous mixing isn’t simple, it can be made easier by understanding the basics of mixing, pinpointing your particular needs, and asking the right questions. Whatever your needs are, Hockmeyer machines have a reputation for performance and reliability, thanks to our decades of experience in the industry and our commitment to innovation. Our high viscosity mixers are designed by an experienced engineering staff incorporating information from customers, our own R&D Laboratory, and years of data from Hockmeyer multi-shaft mixers.

Ready to learn more, or looking for advice? Our team is here to help.