The ability of a liquid to flow freely can have a great impact on the type of bottle filler used to package that product. While free flowing liquids such as water and other beverages can still present packaging challenges in some circumstances, those challenges tend to intensify when dealing with a high viscosity product. First, these products flow slower, which can present challenges with speed, but they also tend to need some extra assistance when traveling from tank to bottle. When thick products are in play, a majority of the solutions will come from one of two filling machines, either a pump filler or a piston filler.
Pump fillers, as the descriptive name implies, will use a pump to assist the product through the pathway and in to the waiting bottles or other containers. The type of pump used for each project will depend on a number of different factors, with the product itself always being one major factor. Pump fillers can be manufactured to fill based on both time and pulse. Time based fills are more or less self-explanatory, allowing product to be pumped into containers for a set amount of time, with each fill head individually adjustable for more accurate fills. Pulse based fills will depend on the type of pump being used as well. For example, with a gear pump, a pulse may consist of an entire turn of the gear, or something less, like a half turn. This principle of filling can allow for slightly better volumetric accuracy over a time based fill.
Piston fillers work in a slightly different manner, using a cylinder and piston to push product in to waiting bottles or containers. As the piston retracts, product fills the cylinder. Once filled, the piston returns to the cylinder to eject the liquid. The size of the bottles being filled will determine the size of the piston used, though more than one bottle size can be accommodated by a single piston. Given that the volume of the cylinder will not change, the piston filling machine provides a highly accurate volumetric fill. This machine also works well with products that contain large particulates such as some sauces and dressings, as the open space of the cylinder allows such solids to pass through.
While both machines can handle thick products, other considerations, such as the particulates mentioned above, will typically make one machine preferable to the other when dealing with high viscosity products. Chemical resistant pumps may be used for harsh products, making a pump filler the ideal choice. Very thick products, such as pastes and putties, may be more suited to a piston filler. Both pump and piston filling machines are available in semi-automatic and automatic models, allowing packagers big and small to reap the benefits of these machines. To learn more about all of the liquid fillers manufactured by NPACK, visit the Filling Machinery section of the NPACK website.