The food industry, however, is the most prevalent application of vacuum packaging as a process rather than product.
Food products are commonly maintained and stored through the use of vacuum packaging as the reduction of oxygen in the container improves product longevity while also increasing visibility, making it a perfect model for the vacuum packaging spokes-product. Food manufacturers package products such as meat, cheese and more in this manner. The trend is gaining momentum in domestic applications as well where small vacuum packaging systems can be used to store anything from food to blankets and clothing in secure protective plastic packaging.
The same principals of freshness, efficiency that enable food to be packaged in this manner apply to other items as vacuum packaging offers protection from moisture and other environmental contaminants such as dust and air while decreasing the amount of space needed for storage. Although most vacuum packaging causes entails large amounts of pressure being applied to a product when the air is removed, gas flushes may be used for the packaging of even fragile materials without risk of harm.
Products contained and protected through vacuum packaging are sealed in thermoplastic material through a four step process, though additional steps may be required for specialized materials. In industrial and commercial applications items are fed into a heavy duty chamber sealer.
These machines place the item into an opened plastic bag or a preformed mold, such as the blister pack or clamshell mentioned before. The chamber is then closed and a high-speed vacuum pump extracts air from the entire chamber. The open portion of the plastic is positioned on a heat strip, which seals edges creating an anaerobic environment. The chamber can then be opened and air is allowed to flow freely as the sealed package is airtight.
Domestic vacuum packaging applications employ smaller, simpler models where items are placed in a plastic bag with a specialized valve to which a vacuum or small vacuum pump is attached for the reduction of contained air. The production of vacuum packaging forms is very dissimilar from the act of packaging, but still requires the removal of air. A sheet of plastic is heated to a soft pliable state and then fed into a form station. A vacuum removes air, pulling the plastic up against a pre-made mold. The plastic is then cooled in place before reverse air flow ejects the packaging. Vacuum formed parts are often used to vacuum package other parts as they are rigid, durable and product specific.