Food Mixers

Technical Articles

Building production and a competitive edge with more versatile mixing equipment

The specifications that define a mixer built for a sanitary application reflect a combination of industry standards and the mixing functions needed for that particular application. A sub-micron emulsion for a mayonnaise, for example, requires high-shear agitation. The size of the mixer is determined by the throughput required. To guard against batch-to-batch contamination, CIP and SIP capabilities are usually designed in, too, along with special devices such as double mechanical seals, to ensure a high degree of repeatability, and to document the production of every batch, we add a multi-axis control system with extensive data-logging.

This close connection between specific performance requirements and equipment features is the logical starting point for equipment design. But today, the challenge of specifying and designing a high-performance mixer is more than a two-dimensional process. We regularly address performance needs that are much broader than one particular mixing application. In fact, we often custom design emulsifiers and homogenizers to meet production needs that have not yet been imagined.

The added value of process versatility.

Specific equipment components - like agitators and sub-surface ingredient injection systems - are critical factors in optimizing performance. But when we look past the process line to the bottom line, the overall versatility of the equipment we build is often more important than any individual component or feature.

Versatility enables the manufacturer to deliver product more quickly. It also enables him to price his product more competitively – by passing on the savings that results from a reduction in waste. This is particularly important for any process involving high-value or scarce ingredients. The small volume of a sophisticated minor material being mixed is often more costly than the mixer doing the work.

Mixer versatility defined

Versatility designed into a mixer can be manifested in many ways. Though the relative importance of these advantages varies from application to application, they all contribute significantly to profitability.

• A mixer is considered highly versatile - and valuable - if it can perform a great variety of mixing functions, such as dispersion, emulsification, and homogenization. This broad functionality may eliminate the need for a secondary piece of equipment (and all the downtime and cost associated with it), such as a pre-mixer or de-aerator. It can at least accelerate the overall mixing cycle by performing many functions efficiently.
• A versatile mixer operates effectively over a wide range of viscosities.
• For many companies, fast product changeover is an essential tool for increasing productivity. This requires a mixer capable of fast discharge and easy cleaning/sterilization. The mixer must also be equipped to allow a quick change in recipes to accommodate the next product.
• The ability to operate consistently over a wide range of batch sizes varies considerably with the design of the vessel and agitators. For many food manufacturers, it is the most important advantage of all.
  

Who profits most from mixer versatility?

The manufacturer whose process line never changes, who always produces the same volume of the same product in the same way, has little need for equipment versatility. For everyone else, versatility is a powerful competitive tool.

• Contract manufacturers - Success in the contract manufacturing business relies upon the manufacturer’s ability to shift gears smoothly and fast. Technical prowess and product consistency are critical, but speed in getting the product to market ultimately makes the difference between profit and loss for both the contract manufacturer and his customer. Campaigns that involve small runs - and small batch sizes - cannot wait for a small mixer to become free on the process line. A large mixer capable of running a batch at 15% capacity will deliver the product immediately and reduce inventory costs.
• Broad-spectrum product manufacturers - The maker of a broad product line must also be equipped to respond quickly to market demand. The manufacturer who is able to re-task his mixers to perform a wide variety of mixing functions has a huge competitive advantage.
• Product innovators - Whether you are a captive or contract manufacturer, innovation requires the ability to perform mixing functions that are not already routine on your process line. Significant process improvements may be available, but you will need open-ended mixing capabilities to find them. For this reason, highly versatile mixers are especially useful in R&D labs and pilot plants.

Equipment strategies for increasing process versatility

The best strategy for improving the versatility and efficiency of your mixing equipment will depend upon the parameters of your particular application. But for most applications, these general guidelines will at least provide a springboard to re-examine your equipment and develop a plan to improve production.

Vacuum minimizes the time dedicated to solids transfer and wetting out.

Vacuum is widely recognized for its ability to accelerate deaeration and intensify the mixing process. You can also use vacuum to transfer additions, and especially low-density powders. This will hasten the process and prevent dust from escaping into the plant atmosphere - improving operator safety and often reducing the risk of explosion. Applied correctly, vacuum readily collapses (or “densifies”) powder agglomerates floating persistently on the surface of the batch and helps to wet them out quickly.

Accelerate emulsification and dispersion by injecting additions directly into the high shear zone.

Additions delivered to the surface of the batch must vortex into the batch and be carried into the high shear zone by the flow of the bulk material. This process is slow and expensive. Numerous batch turnovers are often required before agglomerates are broken down and a uniform distribution is achieved.

cont...