The right specialty coating systems for animal feed will help to produce higher-quality end products while making the entire process more efficient. The wrong coating equipment during animal feed processing can introduce problems and inefficiencies. Which animal feed processing equipment works best depends on a number of factors, including the type of animal feed, type of liquid additives, surrounding processing conditions, and more.
Choosing Speciality Coating Systems for Animal Feed Processing
Liquid coating processes have become increasingly important in all types of animal feed processing, from pet food to poultry feed to aquatic feed and more. Liquid coatings often supply essential fatty acids, vitamins, and nutrients the animals need to develop healthy bodies, or to grow quickly. This generally involves a coating process over feed pellets.
Some of the challenges facing specialty coating systems include ensuring that the liquid coating is uniform across the pellet and that all pellets receive a coating. Different liquid coating systems have different ways of meeting these challenges.
Mist Coating
Mist coating is a highly efficient specialty coating system in animal feed processing. Through this process, pellets are coated using atomization. Liquid falls on quickly-moving, rotating disk applicators and turns to mist. Pellets fall on all sides of the spinning disks and move through the mist. This results in an even coating as the pellets fall. Since the rotating disk does not require spray nozzles, like many other speciality coating systems do, mist coating can avoid clogs. This is especially helpful when working with heavy fats, oils, sugars or salts, which can collect on the ends of the spray nozzles and create clogs.
Spray Coating and Mixers
Spray coating uses mixers and spray nozzles to coat pellets. The mixers might use paddles or ribbons to mix the material or move it forward while the spray nozzles coat the material. The spray nozzles are unlikely to evenly coat the pellets by themselves, so this method relies on the mixing action to create an even coating.
If the mixer is insufficient—it doesn’t mix long enough, the mixer is overfilled, or the construction isn’t correct—the mixing action may be insufficient as well, which can result in an uneven coating. The spray nozzles can also become clogged with liquids that use heavy fats, oils, sugars or salts. These clogs won’t happen at an even rate, so fixing one clog won’t necessarily prevent another. The clogs can also create excessive backpressure, which can damage other parts of the liquid metering system.
Vacuum Coating
Vacuum coating uses air pressure and a vacuum space to ensure liquid ingredients stick to dry pellets. This method helps liquid ingredients not only stick to the surface of the pellet, but also brings the liquid ingredients into the pores of the pellet. This can result in a more even and thorough coating. It’s also possible to distribute multiple layers of coating through this process. However, if the pellet will be damaged or oversaturated with too much liquid, this might not be an effective solution.
Vacuum coating starts by creating a vacuum space inside the coating equipment. One or more layers of liquid coating is then added to the dry pellets or other products. Then, when air enters the chamber again, the pressure brings the liquid coating into the pellet’s pores and causes it to stick to the surface. This process generally protects the pellets from crumbling, but it can reduce the “crunch” quality of the pellet and make it more elastic.
Understanding and recording the liquid ingredient characteristics, as well as the dry ingredient characteristics, and other parts of the liquid processing system will aid in the design of the optimal animal feed processing equipment. Talk to your equipment manufacturer about the liquid metering system, liquid system pump, measurement system, and other essential components. Careful consideration will help to prevent problems and keep your system working properly.
