Pelletizers are used in various industries to convert materials into pellets, which are small, typically cylindrical particles. The choice of pelletizer depends on the specific application and the characteristics of the material being processed. Here are some common types of pelletizers:
Underwater Pelletizer: This type of pelletizer submerges the extruded material into a water bath immediately after it leaves the die. The sudden cooling and solidification in water help to form pellets. Underwater pelletizers are commonly used in the plastics industry for materials like polyethylene and polypropylene.
Strand Pelletizer: In this type of pelletizer, the extruded material is cut into pellets as it exits the die by a set of rotating blades. The pellets are then conveyed away from the cutting area. Strand pelletizers are often used for plastics, rubber, and some food processing applications.
Air Pelletizer: Air pelletizers use airflow to cool and shape the extruded material into pellets. They typically consist of a die plate with many small holes through which the material is extruded. As the material exits the holes, it is cut into pellets by knives or blades and cooled by surrounding airflow. Air pelletizers are suitable for materials that require gentle handling or for applications where water cannot be used.
Disk Pelletizer: Disk pelletizers utilize a rotating pan or disk to agglomerate fine materials into larger pellets. The material is fed onto the rotating disk, where it is agitated and formed into pellets by a combination of centrifugal force and the action of the disk's motion. Disk pelletizers are commonly used in the fertilizer industry but can also be used for other materials such as ores and minerals.
Rotary Drum Pelletizer: Rotary drum pelletizers consist of a large rotating drum or cylinder where material is fed in along with a binder if necessary. As the drum rotates, the material is agglomerated and formed into pellets by a combination of tumbling action and the addition of liquid binders. Rotary drum pelletizers are often used in the production of fertilizers, animal feed, and other granular materials.
Extrusion Pelletizer: Extrusion pelletizers utilize an extruder to force material through a die, forming continuous strands. These strands are then cut into pellets of desired length. Extrusion pelletizers are commonly used in the production of food pellets, such as breakfast cereals and snacks, as well as for certain plastic materials.
Each type of pelletizer has its advantages and is suitable for different materials and applications. The choice of pelletizer depends on factors such as the material's characteristics, desired pellet size and shape, production capacity, and required process flexibility.