Common LN2 Applications
by Phil Redenbarger and Chris Hebb, Technifab Products Inc.
February 1, 2010
Bottlers of noncarbonated soft drinks, juices,
water, wine and beer many times use LN2 injection
equipment to insert small measured drops of LN2 into
their containers.
Bottlers of noncarbonated soft drinks, juices,
water, wine and beer many times use LN2 injection
equipment to insert small measured drops of LN2 into
their containers. Processors of nuts and other perishable items also often use LN2
to provide an inert atmosphere in containers. Soft food packages are also
pressurized by liquid nitrogen injection to protect the package contents from
crushing.
When used for inerting, the dosed liquid rapidly evaporates into tasteless,
colorless, odorless, inert gaseous nitrogen that displaces the oxygen-laden air
in the container. The container is then sealed, resulting in an inert
environment. By reducing the oxygen content of the environment, the LN2
dramatically extends the product shelf life.
When used for pressurizing, a small dose of liquid nitrogen typically is
introduced into the container after it has been filled with product. The
container is immediately capped or sealed, trapping the expanding gaseous
nitrogen and creating positive pressure inside. Pressurizing enables processors
to use thin packaging materials and yet be able to stack them for
distribution.
Liquid nitrogen pressurization is often used in hot filling operations. The
pressure introduced as a result of the nitrogen dose compensates for the vacuum
conditions created when the hot product cools to ambient temperature. Without a
dose of liquid nitrogen, some thin containers made from such materials as HDPE
or PET would collapse when the hot contents cool to ambient temperature.
Pressurized PET bottles are also less prone to “jamming” on high-speed lines
and create a better surface on which to affix labels. The enhanced surface
makes it possible to use less costly labeling materials and reduce overall
packaging costs.
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