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By Mike Pehanich, Plant Operations Editor | 08/20/2007
Tetra Pak’s answer employs bottom-of-tank entry which, when coupled with vacuum, radically reduces air intrusion in the mix. European processors have used such systems more than their American counterparts. “It is far more effective with difficult powders,” says Berlan.
High-shear mixing under vacuum today has clear advantages. Such systems help dissolve more of the ingredient mix in small quantities of liquid and enable the processor to avoid “fisheyes” in the mix. “A lot of water might not be what you want in your recipe today,” says Berlan. “With the demand today for these products, recipes will become more and more complex.”
Floor-loaded Admix Fastfeed mixers also are designed to take in powders or liquid under vacuum. The high-shear mixers disperse powders effectively, and they allow quick changeover and blending accuracy.
The valves on the powder hopper allow you to monitor the amount of powder that goes into the liquid,” says Keith Cheries, national sales manager for based Admix Inc. (www.admix.com), Manchester, N.H. “It’s easy to change and adjust. Some powders go in easy; some are more difficult. But with our system, it is easy to change powder feed rate.”
“The biggest need in the industry today is on-the-fly mixing or high-shear mixing,” he adds, noting that his company’s Fastfeed mixer incorporates powder into liquid and gives it a shot of high shear on the fly before it can agglomerate, fisheye or glump. The worker-friendly floor-loaded equipment also has important ergonomic advantages. Mounted on casters, it becomes a piece of equipment that can be wheeled almost anywhere in the plant — answering the ongoing need for versatility and flexibility in plants everywhere.
High-shear mixing is the dominant trend, agrees Chris Ross, vice president of sales for Charles Ross and Son Co. (www.mixers.com), Hauppauge, N.Y. His company has introduced a patented technology, its X-series of MegaShear and ultra-high shear equipment for fine emulsions and dispersions.
High-shear mixing under vacuum will be changing the look of mixing in a plant, Berlan believes. The absence of bag opening and poured top entry translates into cleaner air and cleaner surfaces — for a healthier and safer plant environment.
In-line blending methods provide processors with alternatives to tank mixing. Instead of the juice maker’s typical blending of water, sweetener and juice in a tank, for example, in-line blending enables the processor to run water or other liquid while adding ingredients in a continuous stream.
“Modern plants are doing this more and more,” says Tetra Pak’s Berlan. “Before, they did it with just syrup and water. Now they are running five or six streams of product into the flow.”
Allowing the processor to blend as needed, in-line blending is more efficient, he argues. “You don’t have to blend in the tank and constantly check your concentration or mix of ingredients. You just blend in line and add ingredient as needed as product flows to the filler.”
“We are seeing a lot more in-line mixing,” says LeClair of APV/Invensys, noting that processors have been switching to his company’s Darmix in-line mixer to get away from batch mixing. “Continuous mixing is a trend driving the industry today.”
Indeed, a manufacturing executive at one of the word’s largest soft drink makers has admitted that his company is considering switching much of its production to in-line systems. He calls them “more progressive” and foresees such systems becoming the norm.
Advantages of in-line blending include:
“Six Sigma methods of checking accuracy favor in-line blending,” Berlan adds. “This is another way in which (new) blending methods are influencing plant design. Your operation becomes very streamlined.”
More and more processors are turning to ribbon blenders for dry blending, spices and flour applications, says Chris Ross. The outer ribbon of a ribbon blender moves product in one direction while the inner ribbon moves it in the other. Ribbons also rotate to move product both laterally and radially.
“Anything that is dry blended can take a ribbon blender or a vertical cone-screw blender,” says Ross, emphasizing the economics of these options.
Other “milestones” in mixing and blending technology, according to Ken Langhorn, technical director of Charles Ross and Son, include: powder-injection technology; agitator/stirrer designs; and high-viscosity blade designs on planetary mixers.
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