A simple nitrogen purge system can greatly benefit packagers in the Food and Beverage Industry by removing oxygen from a container. Replacing oxygen with nitrogen – either just before performing the fill, just after the fill or right before capping a container – can prolong the product's shelf life while preserving the taste, color and texture of the food or beverage.
To understand how the nitrogen purge system works, consider the packaging process and the effects of oxygen on foods and beverages. On automatic packaging lines, bottles and / or other containers will be loaded on to a power conveyor system using a laning conveyor, a loading turntable, using manual labor or in some other manner. Of course, the bottles that are loaded on to the conveyor are empty, and in the Food and Beverage Industry will likely travel through a rinsing machine or other container cleaning machinery to remove dust and debris prior to continuing down the packaging line.
While the container cleaning equipment helps keep the packaging process sanitary and removes dust and debris build up, it does not have the same benefits as using a nitrogen purge system. While container cleaning equipment helps keep the product free from outside contaminants, nitrogen purge creates an atmosphere that assists in prolonging the useful life of a product.
Once rinsed or otherwise cleaned, containers will normally move to the filling machine. At this point, a nitrogen purge can be set up to inject nitrogen into a container before the container is filled with product. The main reason for using a nitrogen purge before a fill, however, is usually not the preservation referred to above. Instead, adding nitrogen to an empty container can strengthen the container, making it more rigid. This is especially useful for certain plastic bottles (like certain water bottles, for example) that are truly manufactured to be a rather flimsy bottle, sometimes to simply save on cost.
More often than not, a nitrogen purge system will be found between the filling machine and capping equipment on a packaging line. Once the container has been filled with a food or beverage product, some headspace will remain – the empty space between the product and the top of the bottle. This headspace, when not run through a nitrogen purge system, can have a detrimental effect on food and beverage products.
In a normal environment, the headspace will be filled with some oxygen. Long term contact with oxygen can lead to the deterioration of food products. When in a closed container, oxidation can destroy vitamins and nutrients as well as help to create an atmosphere for the breeding of certain bacteria and other contaminants that lead to spoiling. Using the nitrogen purge system removes the oxygen from the headspace, replacing it with nitrogen gas to counteract the negative aspects noted above. As bottles or containers leave the filling machine, or as they enter the capping machine, a purging head will blast the headspace with nitrogen gas. Immediately capping or otherwise sealing the containers minimizes the oxygen captured in the headspace. The result, less oxidation and an environment less likely to foster bacteria and other contaminants, which in turn leads to a longer shelf life and the retention of the normal taste, color and texture of the food or beverage product.
Nitrogen purge systems can be manufactured in many different shapes, sizes and forms. Single head machines can attach directly to a conveyor system to purge each bottle as it passes under the purge machine. Other nitrogen purge machines may be manufactured with multiple heads on a single frame, allowing the machine to roll up to an existing packaging line. In general, each nitrogen purge system will be manufactured based on the project for which it is built, with production demands and the existing equipment greatly influencing the design.