Filling Machines and How They Work
Filling bottles can seem like a fairly simple process, just get the liquid into the containers. However, each type of filling machine manufactured by Liquid Packaging Solutions gets the liquid into the bottle using a different principle, such as filling to a level or to an accurate volume. It is this accuracy, combined with greater efficiency, that makes bottle fillers an integral part of a packaging system.
Gravity Filling Machines
Gravity fillers allow packagers to get an accurate volumetric fill by placing a tank above the fill heads. As you might imagine, gravity plays a large part in completing the fill. With the raised tank, valves can be opened and closed for a pre-set amount of time to allow product to flow from the tank into the waiting bottles. When that pre-set time elapses, the valves will close cutting off the flow of the product. The time for each fill head can be set individually to allow for accurate volumetric fills on multiple head machines. Given that gravity is the main mover of product with these liquid fillers, the gravity filler is best suited to free-flowing products, as thicker, slower moving liquids would not allow for an efficient fill.
Pump Filling Machines
Pump filling machines also allow for an accurate volumetric fill but add a little boost to the movement of the liquid. Unlike gravity fillers, pump filling machines will use a single pump for each fill head to move product through the pathway and into the bottles. Pump fillers allow packagers to fill by time, like a gravity filler, or by pulse. Pulse fills correspond to a specific movement of the pump or pump components. For instance, for a gear pump a pulse may be equal to a half turn of the gear. The pumps allow thicker products to be efficiently moved where gravity alone may not suffice, and either the timed fill or the pulse will provide an accurate volumetric fill.
Piston Filling Machines
Finally, piston filling machines also allow for a volumetric fill, but in a slightly different manner than the filling machines described above. With this liquid filler the piston moves in and out of the cylinder. As the piston retracts, product is pulled into the cylinder. The piston then returns to the cylinder to push product out and into waiting containers. As the volume of the cylinder never changes, the piston filler provides an accurate volumetric fill. Like the pump filler, the piston also provides an extra push to help move product, and the open space of the cylinder makes this machine ideal for highly viscous products as well as product with particulates, like jams with fruit pieces.
Overflow Filling Machines
Rather than fill to a specific volume, overflow fillers fill each bottle to the same level, even if volume will vary slightly. This bottle filler uses a special nozzle that dives onto the container and creates a seal over the bottle opening. Product is then released and continues to flow until it reaches the desired level. Once that level is reached, the liquid returns to the holding tank via an overflow opening in the nozzle itself. Once product stops flowing the nozzles rise from the container creating a level fill. These machines are ideal for those packaging in a clear container where a product line on the shelf is obvious. While the overflow filler does use a pump to move product, it is also better suited to low or medium viscosity products as thicker products would take an excessive amount of time to fill and could clog the product pathway or return port to make achieving level fills difficult or time consuming.
While most packagers will either fill by volume or to a level, there do exist other principles for different products, including a net weight fill. To learn more about all of the different principles, or for assistance in finding the right principle for your own products, call LPS and speak with a Packaging Specialist today.