Argon Purge versus Nitrogen Purge

Nitrogen and argon purging in the packaging industry are typically done to protect against oxygen reactions that can break down certain products. Certain food products, for instance, will spoil quicker when exposed to oxygen. By displacing the oxygen in a container or container headspace with nitrogen or argon, the products exposure to oxygen is minimized, which results in benefits such as a longer shelf life and an extended retention of flavor, color and texture.

On a packaging line, the purging system can work in a number of different ways, but the most popular method involves setting up the purge machine between the liquid filler and the capping equipment. The purge will occur after product is placed in the container and just before a cap or other closure is applied to the bottle, to prevent as much of the nitrogen or argon from escaping before the product is sealed. But when purging, when should nitrogen be used over argon? Or argon over nitrogen?

The truth is, though the two gases have their differences, the choice often comes down to economics. A very general chemistry refresher will show that argon is a noble gas, or completely inert - chemically inactive. Nitrogen, while not a noble gas, is also an extremely unreactive gas. Both are odorless and colorless, another benefit when packaging foods, beverages and other products. However, nitrogen makes up a large portion of the air, while argon is a small percentage of that same air. For this reason, nitrogen can be a less expensive option when purging on a packaging line, and tends to be the more popular choice.

The next obvious question is why would anyone use argon? Argon is a denser gas than nitrogen, and, as noted above, completely inert. Due to the density, the argon may be slightly more difficult to disperse after the purging than would be the nitrogen gas. Meaning that where the importance lies on not letting oxygen back in, argon may be preferred.

As to the manufacture of the machinery, whether the typical set up or a custom design, the equipment will be virtually the same whether purging with nitrogen or argon, with the choice of the two coming down to the preference of the packager. Therefore, the equipment price will change very little, whereas the operation cost can have a more significant gap between nitrogen and argon. Packagers will need to weigh the costs and benefits of each to decide which will better suit their specific needs. For more information on purging equipment or for help deciding which type of purge would be best for your project, contact Liquid Packaging Solutions, Inc. today.