Preparing Thick Products - Viscous Liquid Filling Machines
From foods like honey and syrup to health and beauty products like shampoos and creams, thick or sticky products can require special handling not necessary when filling free-flowing, water-like liquids. A viscous liquid filling machine from Liquid Packaging Solutions can help ensure consistent fills while meeting speed requirements and production demand.
Simply put, viscosity refers to the resistance to flow. Generally speaking, the higher the viscosity, the thicker the product, the slower the flow. While most drinks can be poured from a can or bottle, most condiments are squeezed from their containers, an example of lower viscosity versus higher viscosity. Just as certain types of filling machines are ideal for free-flowing products, such as overflow and gravity fillers, there are certain liquid fillers that are designed to fill high viscosity products. Key features often found on a viscous liquid filling machine are discussed below.
1. Pumps
With a gravity filler, free-flowing products are simply placed over the fill nozzles, and the natural force of gravity allows the free-flowing liquids to move from a tank to the bottles or other containers. As viscosity rises in liquids, such a process would either become incredibly inefficient or, for the highest viscosities, simply would not work. Viscous liquid filling machines can include pumps to help move the product through the pathway and into the waiting containers. The extra push of the pumps helps speed up the flow and returns the efficiency to the filling process. Pump filling machines typically include a single pump for each fill head, ensuring not just an efficient, but also an accurate, filling process.
2. Pistons
As an alternative to adding pumps to a filling machine, those filling thick liquids may also use a piston to achieve the same benefits. The piston filler allows the piston to retract from the cylinder while pulling liquid into the cylinder. Once full, the piston gives the same extra push to high viscosity products to help move them into the containers. As the volume of the cylinder stays the same with each stroke of the piston, this type of fill also keeps the process consistent as well as efficient.
3. Modified Fill Nozzles
Viscous liquids may have a tendency toward clogging, dripping, or even bubble during the filling process. Modifications to fill nozzles can often help overcome these issues. Wide mouth nozzles help to facilitate the flow of thicker products without clogging, even when products like jams and sauces container particulates like chunks of fruit or vegetables. Anti-drip, or positive shut off nozzles, can help to keep product from splashing onto the outside of the bottle or the conveyor, avoiding a mess during packaging. Filling machines may even use nozzles that dive into the container and rise while filling, to avoid air pockets or bubbles that may form when dealing with thick liquids. The nozzle type used for a viscous liquid filling machine will be determined by the specific characteristics of the products that are being filled on a case-by-case basis, to maximize efficiency.
4. Heated Pathways
In addition to pumps, pistons, and special nozzles, other products, whether high in viscosity or even a solid in their final form, will be heated to facilitate the filling process. Heated tanks, tubing and nozzles keep these products at a higher temperature as they move through the filling machine. The change in temperature brings on a change in viscosity, making certain products more free-flowing in their heated state. Candles, deodorant, or lipstick can be efficiently prepared for the consumer by heating the products to a liquid form, or a lower viscosity. While not every high viscosity product will require a viscosity change to encourage a better flow rate, heated pathways offer an option for tough filling projects.
Different filling machine types and different filling principles allow for a wide range of liquid products to be prepared across almost every industry in existence today. While exceptions to the rule always exist, filling machinery built for viscous products will likely include one or more of the features mentioned above.
Since our start in the industry, Liquid Packaging Solutions has filled products both thick and thin, including molten and sticky brands that required a heated pathway. If you have questions about the best way to manage your filling project, feel free to contact LPS and speak with a Filling Specialist to help you find the best solution for your own packaging process.
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