We recently touched on filling machines for free-flowing products, and the usefulness of both gravity fillers and overflow fillers for such products. However, not all packagers will be filling liquids with low viscosities. Thicker products require more than just gravity to move them through the product pathway - from the tank, through the fill bar, down the tubing and into the waiting bottles. Just like free-flowing products, there are different options to fill high viscosity products, below we will discuss arguably the two most popular in the pump and piston filling machines.
The extra boost for thick products can come in the form of a pump. Pump filling machines will use a single pump for each fill head found on the machine, with the pump being matched to the product. Each pump can then be set to move product either during a pre-set time or by a "pulse". Timed pumps simply move product for the duration of the time set, with an ability to ramp speeds up and down to reach consistent and accurate volumes. Pulse settings will depend on the type of pump used, but can be set for a specific number of pulses. For example, on a gear pump, one pulse may equal a full or fractional turn of the gear.
Both automatic and semi-automatic pump fillers are available from NPACK, offering packagers large and small an option for filling thicker products. Semi-automatic machines may be as simple as a tabletop filler or may be manufactured on a full frame to allow upgrades in the future.
Using a piston filler is a second option for filling thick, or high viscosity, products. As the piston retracts, product is pulled into the cylinder. The piston is then used to push product out of the cylinder and into the waiting containers. With the piston retracting to the same point with every cycle, the same amount of product is brought into the cylinder, allowing for an accurate volumetric fill. While piston sizes can vary, retraction points can also be set, which allows the same size piston to fill a range of container sizes.
Just like the pump filler, piston filling machines are available in different levels of automation for packagers large and small.
While other options may exist for individual packaging projects, both of these liquid fillers are ideal for higher viscosity products. In addition, liquids with particulates, such as jellies, jams, sauces and dressings, can benefit from these machines. To learn more about pump fillers, piston fillers or any of the bottle fillers available from NPACK, visit the Filling Machinery page of the NPACK website.