Pelletizers

Pelletizers

Pelletizers are process machines that form materials into pellets for use in subsequent operations.

Common Types

There are many different types of products. Examples include Disc Pelletizers, Drum Pelletizers, and Strand Pelletizers.

Disc or pan pelletizers

Disc or pan pelletizers are continuous-process machines which add raw materials to a large process vessel (the pan) and then spray the particles with water. As the pan rotates, the moistened materials form intermediate-sized particles and then larger agglomerations which exit the equipment.

Drum pelletizers

Drum pelletizers produce dense, large-diameter pellets for disposal, recycling or transportation. They have a rear-mounted, auger feeder and a drum-shaped process chamber.

Strand pelletizers

Strand pelletizers have bolt-on knives and quick-change gears for processing materials such as engineering plastics. They feed extruded strands of material into a rotary, cross-cutting head which reduces the stock into pellets of uniform size. Pelletizing systems use wet or dry processes.

Common Design

Pelletizers with water jets and a water-slide design are designed to contact and cool the process material. After water jets spray the material, the excess water drains through a trough. The feed roll then moves the process material to a cutting area with bolt-on knives. With water-slide pelletizers, the pellets are bathed with water and then dried with a centrifugal water separator. In dry-cut systems, the water is removed before the strands enter the cutting chamber. Although water-slide designs are popular in marine salvage operations, dry-process pelletizers are used to cut and cool pellets of temperature-sensitive materials such as engineering plastics. Examples include acrylonitrile butadiene styrene (ABS), high density polyethylene (HDPE), low density polyethylene (LDPE), nylon, polyolefin, polypropylene (PP), polystyrene (PS), and polyvinyl chloride (PVC). Some pelletizers are hydraulic. Others are electric-powered machines with two motors. One motor powers the feed roll and the other moves the rotor. Typically, capacity or production rate is measured in pounds per hour (lbs / hr). Other specifications may vary by pelletizer's type. For example, disc pelletizers and rum pelletizers carry specifications for diameter, depth, length, width, height and shipping weight. Parameters for strand pelletizers include working width, strand rating, standard strand velocity, standard rate per strand, optional strand velocity, optical rate per strand, motor size, maximum rotor speed, voltage, type of drives, and number of cutting edges.

Advantages

• Heating wood pellets offers distinct advantages over conventional fossil heating fuels and other forms of wood burning
• Reduces our dependence on oil, natural gas and propane – all non-renewable fossil fuels
• Pellet fuel is a renewable fuel when wood is derived from sustainable sources
• Using locally-sourced pellet fuel circulates your fuel dollar in the local economy
• Displacing fossil fuels with pellet fuels reduces the emission of greenhouses gases, thereby helping to alleviate climate change
• Since pellet stove emissions are so low, they can be burned in areas that have conventional wood burning restrictions
• Only minimal clearance is needed for appliance installation. Because of the near total combustion (around 98.5%) pellet stoves produce virtually no creosote. This also allows installation of a pellet stove by direct vent... without a chimney!

One ton of wood pellets has the heat value of about one and a half cords of wood and stacks easily in one third the space! This makes it possible to easily store fuel for the entire season.

The advantages of the pelleting machine also reside in the fact that the pre-pressing stations and main pressing stations can be formed uniformly and independently from one another, and removed as a structural unit from the pelleting machine.

In other words they can be maintained at a remote place so that meanwhile they can be replaced by similar parts. This is true both for the pressing compactor manufacturer with their bearing and as an enclosed structural unit, as well also for the drive housing with the drive for the pressing roller which must be worked after being separated from the pellet machine, for the purpose of change of maintenance, an exchange of the matrix disc, cleaning or repair.

A further advantage of the above mentioned divisibility is obtained when during a dismounting of a pressing roller it is not necessary to release all electrical conductors and to remove the end switches and therefore it is not necessary to adjust again the whole pressing station. The drive housing for the pressing roller can be releasable connected with a housing of the granulator.