1 May 2018

​Chilling and freezing tunnel vision

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This article originally appeared in Meating Point magazine, edition #19/2018. Full version here.


The ability to efficiently and reliably chill and freeze products is one of the essential ingredients for success in the meat processing industry.

Carton chilling and freezing tunnels are an innovation that was developed by New Zealand-based engineering company Milmeq in the 1970s. Today, Milmeq is the global leading supplier of automatic chilling and freezing tunnels for cartons to the meat, poultry and cheese industries worldwide. With more than 60 years’ experience in the industry, Milmeq knows how meat processors work and has designed solutions to meet their specific needs.

A fully automatic operation, the tunnels have a fast chill or freeze which improves shelf life and product quality and is suitable for multiple product types and carton sizes. The tunnels feature interfacing conveyor systems for automated loading and unloading, eliminating manual handling and reducing the incidence of injury, while preserving product quality.

Where a MILMEQ® chilling or freezing tunnel is installed to replace a blast cell freezer, chilling or freezing time is considerably reduced. In addition to lowering the refrigeration index, the faster cycle time means speed to market is increased and less inventory is held on the processing site at any given time.

Compared to conventional blast cell freezing, the tunnels provide an estimated 25% reduction in energy use and physical footprint and its densely packed, vertical design has led to a 50% reduction in building cost. As an in-line process machine, their first in first out automated system eliminates the need for staggered shifts to manage the chilling and freezing process.

Milmeq’s chilling and freezing tunnels boast an impressive reliability record and have helped improve the overall efficiency of the many processing sites where they have been installed.

As demand continues to increase, so does the need for reliable machinery that can deliver a continuous performance. With their simple design and few moving parts, the tunnels have proven their value, especially for Dawn Pork and Bacon. A pork producer in Ireland, Dawn Pork and Bacon had a freezing tunnel installed more than 10 years ago. Since its installation, the tunnel has required less than five hours of shutdown outside of scheduled maintenance. Production manager Alan Wall said the plant’s throughput continues to be reliable because of the tunnel’s performance.

As an automated technology, their chilling and freezing tunnels have revolutionised food processing systems by eliminating labour costs and worker injury risk.

Deliberately designed to ease the headache of finding and retaining reliable labour, no staff are required to either load or unload cases to and from the tunnel. All cases, or totes, are conveyed into the tunnel, and then, after being cooled, are conveyed out.

The tunnels employ an air blast-based system that provides uniform conditioning to either chill or freeze product. Typical cycle times range from 2 to 48 hours.

The integrated control system designed for each system delivers complete tracking of all product within the system, which aids inventory control.

As businesses continue to grow and develop, the tunnels can be designed with a plan for future expansion to be incorporated. The tunnels are manufactured to meet the client’s specific throughput requirements, but the capacity is easily expandable by lengthening the tunnel when required.

The tunnels can be designed to use a variety of refrigerants to suit site preferences, including CO2 and ammonia.


Case studies

The success of Milmeq carton tunnels has been proven with more than 100 installed in food processing sites around the world. Recent installations include:


Freezing tunnel installed at Banham Poultry

UK-based poultry company Banham Poultry Limited approached Milmeq to supply a freezing tunnel to replace an older tunnel from
another provider which was no longer operating reliably and increase its production capacity. With a throughput of 6,370 chicken cartons (approximately 16.5 kilograms each), the tunnel freezes the cartons from 14°C to -18°C in 24 hours.

Special Projects Manager Bob Waterson said the tunnel’s reliability and freezing performance were integral to the plant’s ability to produce high quality poultry products.

“We never have any concerns about the product being frozen in the allocated time. With the tunnel’s automation, we’re able to turn it on and walk away, knowing the tunnel’s performance is highly reliable.”


Chilling and freezing tunnels at SuKarne

Mexico’s largest beef processor SuKarne was wanting to increase its capacity and expand into international markets and looked to Milmeq’s tunnels to achieve this. It installed three freezing tunnels and four chilling tunnels in its processing sites across the country.

Plant Engineering and Design Manager Juan Miguel Michel Ezrre said the tunnels were robust and have increased the plants’ yields.

“I can honestly say they are fastest and smoothest machines I have ever operated. After the great performance and quality of the first tunnel installed, we decided to have a Milmeq tunnel in each one of our plants.”