Plastic recycling is becoming an increasingly large business. In fact, just in the period from 1990 to 1999, the number of plastic recycling plants grew from 923 to 1,677 - an amazing 81% increase. Currently, the largest number of plastic recycling facilities are in the Midwest, with the second largest concentration being in the Southern United States. In addition, plastic recycling is a relatively simple process after the various types of plastic have been separated from one another.
Types of Pulverizers
Generally, the first step in plastic recycling after the types of plastic have been separated is to run the plastic through the pulverizer. This machine smashes the plastic into tiny shreds or granules.
There are many different types of pulverizer machines. Some are used to break down other materials, such as rock, glass, wood, metals, and cement. When it comes to plastic, the three primary types of pulverizers are granulators, shredders, and ring mills.
A granulator utilizes thousands of evenly spaced blades in order to shred the plastic into finely minced material. After it is minced, it can be melted and reformed. A shredder is similar to a granulator in that it contains evenly spaced blades, though these blades cut the plastic into strips. Some cut both vertically and horizontally in order to create square shaped plastic pieces. A ring mill, on the other hand, has a large, steel rolling blade. This blade chops and grinds the plastic that is placed inside the roller. After it has been ground up to the desired size, it falls through the small holes located beneath the rolling blade.
The Plastic Granulator
The granulator is the most common type of pulverizer used with plastic recycling. It is capable of turning jugs, large bottles, and other plastic products into flakes, which are referred to as granules. These granules are then sold to manufacturers in order to be remolded into new products.
The machine itself is essentially a large electric motor with a rotor. The motor rotates the rotor, which contains cutting blades. The motor, the rotor, and the blades are all located inside a closed chamber in which the plastic is placed. The blades and the chambers of plastic granulators are available in various sizes and shapes in order to meet different needs.
There is also a screen located inside the chamber. This screen sifts the plastic in order to ensure all of the pieces are small enough to be reused, which generally ranges from .125 to .375 inches. Any pieces that are too large to fit through the screen are processed once more within the granulator.
The efficiency of a plastic granulator is based upon how much plastic it can shred in one hour, which is referred to as its pounds per hour rating. For industrial recycling purposes, the plastic granulator needs to be very large in order to process massive amounts of plastic. There are, however, smaller plastic granulators available for home use. No matter the size, these machines can be dangerous. Therefore, it is important to always follow the manufacturer's instructions when using a plastic granulator.
A plastic granulator also must be kept clean in order to remain efficient. Usually, the screen of the plastic granulator is cleaned out after each large job. Otherwise, pieces of plastic can get stuck in the screening and prevent other granules from falling through. The blades of the plastic granulator also need to be wiped clean and oiled to keep the machine running smoothly.