The roller shell is an important accessory of the granulator, and it is also extremely easy to wear just like the ring die. A ring die or a flat die granulator is used to extrude powdery material into granulated feed in the feed production industry, and both of these dies must be used in conjunction with the roller shell to extrude the feed. As one of the most important part of the granulator, the press roller usually wears out 2.5 times faster than the ring die, so choosing a suitable press roller can significantly reduce production costs.
Types
Corrugated Roller Shells
For pelleting industry, Corrugated Roller Shells are the most popular type. Roller shells with corrugation can effectively reduce slippage of the raw material on the surface of the mold, as well as provide a certain amount of resistance to toplugging the die. Although this type of roller shell can press the raw material well, it will have uneven wear.
Dimpled Roller Shells
The Dimpled Roller Shells, also known as honeycomb or perforated roller shells, offer less drag and less pressing capacity than Corrugated Roller Shells, allowing them to last longer and wear more evenly on pellet dies. 'Dimpled' holes at the surface of Dimpled Roller Shells add friction to the die surface and provide better traction.
Complete Roller Shell Assemblies
For all granulators, we supply complete press roll assemblies
Effect
A granulator roller shell mainly works with the mold in order to cut, knead, inlay, and extrude raw materials to achieve granulation.
Material
In terms of roller shell materials, our company mainly uses high carbon chromium bearing steel (GCr15), or uses other materials as per customer requirements. After quenching and low temperature tempering, GCr15 exhibits characteristics of high hardness, uniform structure, long wear resistance, and fatigue resistance.
Service life
The roller shell of the granulator is used to extrude the raw materials. Long-term friction and extrusion force causes the outer surface of the roller shell to wear easily, and indentations appear. In addition to the normal wear and tear of the raw material to the roller shell, the uncleaned grit, iron filings and other hard particles in the raw material will aggravate the wear of the roller shell. Since the linear speed of the roller shell and the ring die are basically the same, but the diameter of the roller shell is much smaller than the diameter of the ring die, the wear rate of the roller shell will be several times higher than that of the ring die.
In the actual production process, the actual service life of the roller shell is only three-quarters of its designed service life. And due to the improper use of the factory, the actual use time is much shorter than the design life. Improper use can also cause the roller shell to fail due to severe surface wear beyond repair. However, if the roller shell wears too fast, it will not only reduce the molding rate of pellet products, but also increase the production cost, which will directly affect the productivity.
