Filling Systems for Any Product Viscosity
Liquid products prepared for consumers can range in viscosity from free-flowing water-like products to thicker items like honey, pastes and gels. While different filling machines may work for a range of viscosities, as a general rule, certain machines are better for low viscosity while others do a better job of handing thicker products. Choosing the right filling system for any project requires analyzing the project in whole, from speed to the bottles, products and more, but starting with product viscosity will move the decision in the right direction.
Filling Systems for Low Viscosity Products
Free-flowing products do not need much help moving through the product pathway and into the bottles. The first bottle filler for low viscosity products uses gravity to move liquid from a tank into the bottles. The gravity filler holds product in a tank above the fill heads and bottles using a force of nature to allow product to flow through tubing and fill heads and into the bottle. Individual time settings for each fill head allows for an accurate volumetric fill for each container.
A second filler used mainly for thin to medium viscosity products fills to a level rather than by volume. Overflow filling machines use unique nozzles to seal bottle openings and release product into a bottle until it reaches a desired level. Once that level is reached, product "overflows" back into the holding tank. The overflow technique tends to work better with products that can freely flow through the fill and return ports.
Filling Systems for High Viscosity Products
When it comes to thicker products, more assistance than mere gravity is necessary to move product through the pathway and into the bottles. Pump filling machines, as the name suggests, use a single pump for each fill head to help the products flow. The type of pump will depend on the product and other factors involved in setting up the fill system. Pumps can fill by volume using either a simple time based fill or by using a pulse based fill which will be equivalent to some movement of the pump. For example, a half turn of a gear pump may equal one pulse.
Finally, piston fillers also provide an ideal fill principle for viscous products. This filler uses a piston that retracts from a cylinder, allowing the cylinder to be filled with product. As the piston moves back into the cylinder, it pushes product through the pathway and into the bottles. Because the volume of the cylinder never changes, piston fillers can provide highly accurate volumetric fills. The open cylinder also makes this filling machine ideal for products with particulates, from smaller particles to chunks of fruits or vegetables found in jams and sauces.
While there are exceptions to the rules, and all other aspects of a project must be taken into account, the gravity and overflow filler will almost always be used for free-flowing products. Pump and piston filling machines will then tend to handle thicker liquids when setting up a filling system.
Liquid Packaging Solutions manufactures a wide variety of packaging machinery, including filling systems. For assistance in finding the best liquid filler for you own project, or for questions regarding the different filling principles, contact a Packaging Specialist at LPS today.