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Dairy Farm Dilemma Solved With Plastic
Friday, 28 July 2006
A recent initiative in the New Zealand dairy industry, designed to speed
up milk flow from farm vat to tanker and reduce collection times, was
recently implemented. To achieve faster flow speed, the outlet valves on
the milk vats and the tanker couplings were increased from 2.5” to 3”.
The outlet valves on the vats were upgraded and the couplings on the
collection tankers replaced. However, this still posed a major logistical
challenge for local farmers, who had legacy CIP (Clean in Place) systems
using 2.5” recirculation couplings. The cost to replace the existing CIP
couplings with stainless steel units amounted to a substantial investment.
Dairy Technology Services Ltd (DTS), a leader in this field, turned to
Millennium Plastics for an innovative solution to the problem. Based on
their brief, Millennium developed an initial design from which several
rapid prototype samples were produced. This allowed DTS to
cost-effectively refine the design and fully prove the concept before
committing to actual production.
Millennium worked closely with DuPont NZ for technical support in
selecting a suitable polymer for the product. A specialist grade of Acetal
resin was chosen, providing a unique combination of strength, toughness
and stiffness, along with dimensional stability. The application also
required the material to be extremely hard-wearing and abrasion-resistant
and able to cope with the harshest treatment handed out on the farm.
In addition, Acetal is chemical resistant and handles a wide temperature
range from -4 degrees C up to 100 degrees C. These are both essential
material properties, as chemicals and hot water are used to flush and
clean the milk vats daily. Being a dairy application, the couplings had
to be manufactured from approved food-grade material.
A critical aspect of the design was to ensure that the O-ring seal
remained in place at all times. With an extremely high tolerance and
attention to detail in the tool development process, a subtle flare was
incorporated into the O-ring flange that allowed it to sit snugly in
place, no matter what.
By developing the CIP coupling in plastic as opposed to stainless steel,
DTS was able to reduce the unit cost by over 75%, whilst still retaining
all of the performance capabilities of the previous stainless units.
As only one aspect of a major industry upgrade project, it was critical
to the overall project that development and delivery milestones were
met. The CIP coupling project, from design concept to final production,
was successfully completed within a very tight timeframe.
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