PET Food Processing - December 2018 - 59

zone, physically contacting the entire batch. According
to the company, these mixers can turnover thick, sticky
or putty-like materials with great efficiency making
them a standard workhorse in many industries.
Depending on the scale of the producer or manufacturer, Reiser also offers a full range of mixer options.
Small-scale producers can opt for a vertical 1-quart to
160-quart bowl mixer that offers a variety of attachments or a spiral wendel mixer. Larger manufacturers
will benefit from a horizontal mixer using a sigma-type
mixing blade, a vertical spindle mixer or ribbon and
paddle blenders, each offering a wide range of capacity.
The sigma-design blade is ideal for mixing developed
and undeveloped mixtures. Some processors may also
benefit from the use of continuous mixers.

Fitting the bill
When it comes to choosing a mixer, Zeak recommends
picking one that allows for a range of mix sizes to fulfill
required production quantities. The production process
is dependent on the mixer size, agitator type and speed
as to how much mixture can be provided and how fast.
Reading Bakery Systems, a long-time supplier of
mixing equipment to the baking industry, also promotes continuous mixing for rotary-molded and nonbaked products. Continuous mixing suits pet food
products because the kill step can be achieved in the
mixer. The higher throughput of continuous mixing
equates to more economical mixer options, says Jim
Warren, vice president of Exact Mixing for Reading
Bakery Systems, Robesonia, Pennsylvania. The company's continuous mixers feature an easy-to-clean-andinspect design and more available surface areas per
pound of product mixed, offering better heat transfer
and improved temperature control.
Other desirable traits of pet food mixers include those
that provide improved sanitation, ease of use and reliability, Warren adds. He suggests processors also consider
the choice of stainless-steel grade 316 over grade 304.
While the grades look similar, the 316 grade contains
molybdenum, which is used to strengthen and harden
steel and to fight corrosion.

Scale up for consistency
With so many options to choose from, it helps to start
by defining the typical volume that will need to be
produced. When working with a new customer, Terry
Bartsch, president and CEO, VMI North America,
Kansas City, Missouri, always inquires, "How much do
you want to make?" VMI North America, an equipment
supplier to the baking industry, often advises pet food
processors to transition from small-batch, high-speed
mixing to continuous mixing, which provides a level of

consistency unmatched by small-batch processes.
Bartsch recommends vertical mixers for certain processors who are ready to transition from small-batch
mixing. These mixers do smaller batches more frequently
and can mix in one bowl while charging or loading ingredients in another, speeding up the process of transporting batches to the production line. Vertical mixing
also allows processors to create homogeneous product
without leaving any dead spots of unmixed ingredients.
"As the pet food industry grows, they will be refining
their needs and looking at what mixers are best from the
standpoint of industry needs and a price point," Bartsch
says. "It makes sense that pet food processors would
begin to look for examples in the baking and meat
and poultry industries as a model for efficiency and
sanitation standards."
Determining the right mixer will always be unique to
the individual needs of each processor and will depend
on the type of ingredients, needed batch size, finishing
processes, production needs, true throughputs and the
amount of material passing through a system or process.
To find the best mixer solution, processors should establish networks across industries to learn from the mixing
successes and failures of others.
PFP

Top: Mixers are often
used for large quantities to standardize
the raw materials to
be processed.
Nu-Meat

Bottom: For
production runs of
several tons or more,
continuous mixers
provide control
over the various
parameters that
can affect product
consistency.
VMI North America

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PET Food Processing - December 2018

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