Filling by Volume Versus Filling By Level

Though we have touched on this issue several times in the past, we like to return to the topic in some manner on an annual basis to remind packagers of the different principles that can be used to fill bottles or other containers. When dealing with many beverages and other products that are water-like in consistency, two different fill principles will make up a majority of the machinery produced to handle these items.

The first type of machine is a gravity filler. Gravity fillers, as the name suggests, rely on gravity to move free-flowing products from a tank to the container or containers. Gravity filling machines provide a time-based, volumetric fill by using nozzles that will open and close for a pre-set amount of time with each fill cycle. The tank will sit above the nozzles and valves to supply the product. Once bottles are in place, operators will activate the fill on semi-automatic models while sensors will relay signals to open valves and allow product to flow on automatic machines. Gravity fillers are an economical solution for free flowing products where a volumetric fill is desired.

Rather than filling by volume, overflow machines will fill each bottle to a level, even where the interior volume of the bottles varies slightly. The overflow principle provides a cosmetic fill, and is typically preferred by those using clear glass or plastic bottles, as the level fill adds to the aesthetic value of the product once it reaches the shelf. Overflow filler use a nozzle that seals over the bottle opening and allows product to enter until the desired level is reached. Also as the name suggests, product will then overflow, or be recirculated, back to the holding tank. Both semi-automatic and automatic machines work in the same manner, but the operator or the sensor will activate the pump to start the filling process with these liquid fillers.

Of course, other filling principles do exist, including other volumetric fills, net weight fills and more. But gravity and overflow filling principles are two popular methods that are often not understood by new packagers. To learn more about other filling principles as well as custom manufactured filling solutions, browse the LPS website or call to speak with a Packaging Specialist today.