Overflow filling machines are unique in that they allow each bottle or other container to be filled to the same exact level even when those bottles and containers may vary slightly in their internal volume. For products that are packaged in clear containers, this can significantly enhance the appearance of the product on the shelf. Imagine bottles of your favorite product with varying levels of liquid in each bottle. Of course, everyone would grab for the bottles that appeared full or over-filled, even if the same volume of liquid was in each bottle. Level fills for products with clear containers not only increase the aesthetic value, but also evade issues of trust or feelings of being cheated due to differing fill levels.
However, some products - distilled spirits for example - are not only packaged in clear containers but must adhere to strict volume requirements as well. Does this mean the packager must forego a fill-to-level system and instead rely on a volumetric filler even though it could lead to uneven levels? Not necessarily, but to work with an overflow filler, such a packager must find a bottle or bottle manufacturer that is consistently reliable in the manufacturing process. The fact is, using either an overflow filler or a volume based liquid filler, the packager must have faith in the bottle manufacturer.
In most industries where specific volumes are a requirement, there still exists a range that will be deemed acceptable. For instance, many distillers will need to fill to a volumetric accuracy plus or minus three percent of a specific target. That range can allow for the distiller to use an overflow filling machine, filling each bottle to the same level for shelf presence while also hitting that three percent volume target. However, this can only be achieved if the bottle manufacturer produces bottles that do not vary more than that three percent in interior volume. Using a volumetric filler also requires some consistency in the manufacture of a bottle to avoid large inconsistencies in fill level!
In a great majority of cases, the bottle manufacturing process for both glass and plastic containers will keep within the acceptable volume range, allowing for the use of a fill-to-level system. However, this is one of several reasons why NPACK, as a manufacturer of packaging equipment, always requests bottle samples for the machines we manufacture. Not only do bottle samples allow NPACK to ensure the equipment works as expected, but it allows us to identify potential issues with components outside of the equipment. In this case, identifying inconsistent bottles before hundreds, or even thousands, are sitting on the production floor waiting to be filled. Identifying issues during the manufacturing process allows the packager to explore alternatives, including modification of the packaging equipment, and can save both time and money for all parties involved.
For more information on fill-to-level machines, volumetric liquid fillers or any of the packaging equipment manufactured by NPACK, contact a Packaging Specialist toll-free at +86-13501921030 today.