In The Mix
by Lynn Petrak
Dairy manufacturers upgrade mixing and blending
equipment to enhance consistency and efficiency.
Giving new meaning to the
term “whipped into a frenzy,” dairy processors facing internal
and external pressures for consistent product quality and enhanced
efficiency are taking a new look at mixing and blending equipment.
Whether updating worn-out machines that have surpassed
their average 15-year life span or investing in the latest equipment as
part of new construction, dairy manufacturers might be surprised at how
mixers, blenders and agitators have become increasingly sophisticated.
The latest systems, like other equipment used in dairy
environments, are constructed to be durable, quick, flexible and sanitary,
developments that are due as much to the demands of today’s users as
they are to technological advances. That is true for units used for
straightforward liquid-to-liquid blends and tank agitation as well as for
more complicated powder-to-liquid combinations, products with particulates
According to suppliers who regularly field calls from
dairy customers, effectiveness is a constant issue because it relates
directly to the quality of the finished product. “The big thing is
when they get to a point where they don’t feel they are getting as
good of a mixture with their current system,” says Randy Verges,
senior applications manager for Fristam Pumps, Middleton, Wis. “We
started getting into mixing and blending equipment after realizing that
everyone has mixing applications in a plant but a lot of people are doing
it the old fashioned way, trying to stir it up. We saw a need for better,
more efficient incorporation.”
Successful mixing and blending is especially important
in today’s processing environments, as dairies continue to diversify
their product lines and develop formulations that are more complicated.
Lou Beaudette, president of equipment supplier Admix
Inc., Manchester, N.H., cites some examples. “The increasing use of
stabilizers used for ice cream, yogurt, cheese and flavored milk drinks
has presented new challenges to processors to find a way to of quickly
dispersing and hydrating them,” he says, “especially some of
the new natural stabilizers used for organic dairy products, a growing
In response to such processing challenges, Admix went
to the drawing board and came up with a new bottom-entry blender called the
LiquiShear for rapid introduction of milk powders, sugars, sweeteners,
stabilizers, cocoa powder starches and gums. “The LiquiShear has a
unique integrated powder conveying and feed system to quickly and
ergonomically feed the above powders at waist height,” Beaudette
says. “This approach increases the safety factor in handling and
processing all of the powders used for dairy processing, while increasing
the efficiency and effectiveness of blending, dispersing and
Fristam also has engineered new mixers and
accompanying pumps to work with today’s powder and liquid blends.
Nearly two years ago, the company introduced a powder-mixer unit that
features a liquid ring pump used in combination with a shear blender.
“It works to pull the liquid and the powder out of the tank and feeds
them into a shear blender unit. It’s economically a very effective
way to shear and mix powders and liquids,” Verges says, adding that
common dairy applications include the incorporation of powders like cocoa
flavorings and those used for nutrient fortification.
Beyond effective blending of powders and liquids,
viscosity is another emerging issue that affects mixing and blending
machines. The development of more viscous dairy products, such as drinkable
yogurts and shake-style milk drinks, has caused suppliers to provide new
mixing and blending solutions to their industry customers.
Verges, for example, says Fristam’s liquid ring
pump that incorporates and feeds powders and liquids into a blender can
handle highly viscous products. “Otherwise, you’d have to put
in a special pump which is more expensive,” he says.
Another equipment supplier, Hauppauge, N.Y.-based
Charles Ross & Son Co. (Ross), recently rolled out a new model of its
Double Planetary Mixer, used for a thorough mixing of ingredients under
low-shear conditions. Ideal for bench-top development of highly viscous
materials, the unit features a vacuum, sight/charge port, jacketed mix
vessel and a thermocouple to sense batch temperature, along with a complete
control panel with a frequency inverter to control blade speeds.
“It’s been out for a while, but we have new
stirrer blades that are being used,” says product manager Bill
Alhofen. “The improvement is for flow characteristics within the mix,
particularly for highly viscous materials, it prevents problems that
were associated with rectangular blades.”
Meanwhile, Delavan, Wis.-based SPX Process Equipment
has worked with more large companies that have expanded product lines to
include thicker products. “We typically sell agitators on heavier new
products, like sauces,” says Tracy Breneman, sales manager for the
nation’s central region. Among its various models for high-viscosity
products used by a range of dairy processors is a series of double
planetary mixers engineered to result in de-aeration of finished
products, fast homogenous dispersions and smoother finished products.
Another equipment maker that has tweaked its mixer
design for flexibility and effectiveness is APV/Invensys, Lake Mills, Wis.
APV/Invensys has upgraded its Flex-Mix Liquiverter mixing system,
which can be used for a wide range of mixing and dispersion applications.
The unit includes a recirculation pump as an option, a dispersion head for
fast operation and improved quality and a direct drive created to reduce
spare parts and cut down on wear and tear. The Flex-Mix Liquiverter can be
tailored to meet specific customer requirements for a particular function.
Designs on Speed
In addition to performance related to effective
ingredient combinations, particularly for new products, there are other
issues spurring suppliers to mix it up with designs for new mixers,
blenders and agitators. Speed is one of them. “Usually, processors
want volume but they want to make sure they pass it through in a certain
amount of time. In some cases, we are cutting down blending time by a half
or third,” Verges says of Fristam’s capabilities. “For
example, if someone is incorporating 100 pounds of chocolate sugar slurry a
minute, now we can do it in 15 minutes.”
Beaudette, for his part, agrees that volume is a key
driver. “In addition to the processing side, we have seen a
substantial rise in inquiries for a more operator friendly and ergonomic
method of adding or ‘feeding’ a high volume of powders into
mixing and blending tanks,” he says. “Admix is addressing this
issue with a new series of powder feed systems, our Fastfeed and Optifeed
products, that use vacuum technology to both move and disperse powders in
line directly to a mix tank, reducing dusting, aeration of the product, and
processing speed, while substantially improving operator safety.”
Finally, sanitation and clean-in-place (CIP) options
have been added to the list of processor requests for new mixing and
blending equipment, given that dairy plants require frequent washdowns with
harsh cleansers in cold temperatures.
Verges, for instance, is quick to note that
Fristam’s new liquid ring pump and shear mixer units are
“CIP-able.” Alhofen, too, says that Ross’s sanitary
mixer is easy to clean for traditional and high viscosity dairy products
and is available in CIP-able models with an incorporated spray nozzle.
Admix also offers stainless-steel construction and easy-to-clean
elements in its various mixing and blending machines.
Rugged, stainless construction that can withstand
frequent cleanings has other benefits as well, as Alhofen notes.
“Maintenance is always a big thing,” he says. “Processors
want low-maintenance equipment that will keep running.”
Lynn Petrak is a freelance journalist based in the
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