Packaging Systems - the Filling Phase
Packaging Systems - The Filling Phase
Once bottles are loaded onto the conveyor system and cleaned where necessary or desired, the containers will normally move to the liquid filling machines. Liquid fillers use a number of different filling principles in order to handle the multitude of products that require packaging. In general, the type of filling machine used on any given packaging system will be determined in large part by the product viscosity, the containers being used and the production rate required, though many other factors may also play a part.
Overflow fillers use a special nozzle to consistently fill bottles to the same level, even when the interior volume of the bottles may vary slightly. Once bottles are in place on an overflow filler, the fill heads dive and create a seal on each bottle. Product is released into the containers, but once reaching a certain level in the bottle, the product exits the bottle via a second nozzle opening, returning to the product supply tank to be recycled through the filling machine. It is this return port on the overflow nozzle that allows the packaging machine to consistently fill bottles to the same level.
Gravity fillers are economical, time based filling machines that also work well with free-flowing, lower viscosity products. In general, fill heads on gravity fillers open for a pre-set length of time each fill cycle. While the fill heads are open, product flows into the bottles from a supply tank positioned above the fill heads. A number of different fill head assemblies can be used on gravity fillers, including fill heads with positive shut off nozzles and diving head assemblies, allowing gravity fillers to handle products with unique characteristics, such as foaming mentioned above.
Pump filling machines also use a time based fill by turning the fill head pumps on and off for each fill cycle. Pump fillers, however, can handle higher viscosity products by using pumps specific to the product being filled. One pump will be used for each head on a pump filling machine and nozzles may vary based on the container being used and the product. For some applications, pump fillers may also use a pulse based filling principle. In these cases, rather than a pre-set amount of time, some component of the pump will move a specified amount. For example, on a gear pump filler, each pulse may be a half rotation of the gear. Pump fillers can handle a wide variety of products, including products with particulates, simply based on the number of different pumps available to use on the filler.
Piston filling machines fill containers based on volume and are highly accurate filling machines. Each cycle, the piston retracts to allow the cylinder to fill with product. Once filled, the piston will push the product out of the cylinder and into the waiting containers. Since the interior volume of the cylinder never changes, the same amount of product is pulled in and pushed out with each fill cycle. Piston fillers work with many product viscosities, but are most often used for high viscosity products like putty and paste. These filling machines can handle not only products with small particulates, but even products that may contain chunks and large particulates (think spaghetti sauce with tomato chunks).
While at least one of the above filling machines will handle almost any product available on the market, some products may require special or custom filling equipment. For example, some products may require a specific net weight in each package, others may need to be heated in order to complete the fill. Products with unique characteristics or even unique packaging may require modifications to the filling machines described above or may simply require custom equipment.
Once the fill cycle is complete, filled containers will continue down the conveyor system to the next packaging phase. Since we do not want product splashing and spilling, that phase will almost always be capping or sealing. Check back later in the week to learn about capping machines and sealing equipment. Or, if you are in a hurry, call Liquid Packaging Solutions toll free today at 1-888-393-3693 to learn more about packaging equipment.