Heavy Duty Rollers are designed for heavy duty mining applications where the belt speed exceeds 5 m/s.The diameters of these rollers generally start from 152.4 mm and may go upto 219 mm. Because of the high speeds at which these rollers have to operate, they need to be robust and are manufactured very accurately to avoid any operating failures under extreme conditions. The shaft diameters generally exceed 30 mm to withstand the radial load.
The high quality machining process is a guarantee for a long service life of the NEC brand Heavy Duty Rollers. Thanks to the high quality machined parts & a non contacting multi-chamber labyrinth seal, the rollers run with a whisper.
Impact Rollers
Impact Rollers are used and positioned corresponding to the load points, where the lumps and the weight of material falling onto the belt could in fact cause damage to it. To limit the impact effect of the material onto the rollers, the latter are covered with a series of rubber rings of adequate thickness and resistance. Impact Rollers are under stress not only from the load of the material, but also from the dynamic forces as the load falls onto the belt. This results in wearing out of the impact rubber rings frequently. However the basic and most important function of the Impact Roller is to save the costly conveyor belt from damage as the cost of repairing or replacing the conveyor belt is much more than replacing a roller.
Guide Rollers
For various reasons, the conveyor belt may at times, tend to drift laterally. In these cases it is possible to utilize vertical rollers with cantilevered spindles. These are generally known as belt guide rollers. It is necessary however to pay particular attention to the use to which these rollers are put, so that the forces on the guide roller by the belt do not damage the belt edge. In other words, guiding does not eliminate the true reason for the belt tracking off. Consequently, the belt may ride over the guide roller or become distorted against it. For these reasons it is advisable to always use guide rollers on the most suitable transom, the self-centralizing transom which rotates automatically whenever the belt tracks off conveyor center and self-corrects.
Return Rollers with Rings
The straight tracking of the belt may be compromised by the type of conveyed material, especially when this material is sticky and thereby adheres easily to the belt surface. In this case, material is also deposited on the return rollers that support the belt, adding an irregular addition of scale to the roller itself. As a consequence, not only wear and tear of the belt occurs, but forces are brought into play to move the belt away from its correct track. Return rollers with spaced rubber rings contribute largely to eliminating the build up of scale that forms in certain conditions on the belt surface. The rings are pointed, assembled at intervals, in the central part of the roller, where they have the scope to break up the scale which normally is present at the belt centre; meanwhile flat rings mounted in groups at the extremities of the belt, support and protect the belt edges, also in cases of limited belt wandering. Return rollers with rings should not be used as belt tensioning devices.
HDPE Rollers
HDPE (High Density Poly Ethylene) Rollers are typically used in the conditions where the surrounding environment is not conducive to the use of steel rollers or where there are limitation of input power. Generally in chemical plants where the steel has the tendency to corrode because of various contaminated gases present in the surrounding air, HDPE rollers are more preferred.
Features
HDPE pipe with reinforced skeleton.
Light weight for power saving and worker safety.
Weight is almost 1/3rd of the steel roller.
Smooth, noiseless operation.
Suitable for corrosion environment.
High installation cost but low operational cost.
Application fields
Chemical Industry
Fertilizer, Salt, Sugar, Pulp Paper, Acid and Alkaline, etc.
General Industry
Coal Mining, Cement, Concrete, Limestone and Quarry, etc.
Operating conditions where source power is limited.
Impact Rollers are used and positioned corresponding to the load points, where the lumps and the weight of material falling onto the belt could in fact cause damage to it. To limit the impact effect of the material onto the rollers, the latter are covered with a series of rubber rings of adequate thickness and resistance. Impact Rollers are under stress not only from the load of the material, but also from the dynamic forces as the load falls onto the belt. This results in wearing out of the impact rubber rings frequently. However the basic and most important function of the Impact Roller is to save the costly conveyor belt from damage as the cost of repairing or replacing the conveyor belt is much more than replacing a roller. 
For various reasons, the conveyor belt may at times, tend to drift laterally. In these cases it is possible to utilize vertical rollers with cantilevered spindles. These are generally known as belt guide rollers. It is necessary however to pay particular attention to the use to which these rollers are put, so that the forces on the guide roller by the belt do not damage the belt edge. In other words, guiding does not eliminate the true reason for the belt tracking off. Consequently, the belt may ride over the guide roller or become distorted against it. For these reasons it is advisable to always use guide rollers on the most suitable transom, the self-centralizing transom which rotates automatically whenever the belt tracks off conveyor center and self-corrects.
