The vulcanized splice is widely accepted as the preferred means of joining two belt ends together to form one continuous belt on the conveyor system. The most commonly used belts for bulk material handling are fabric carcass and steel cable. There are many variations in the composition of fabric carcass belts and there are variations in steel cable belt structure resulting from the tensile strength requirements. In addition to these variations, there are special vulcanization techniques required for the different rubber materials used by the Conveyor manufacturers. Also, there are a number of specialty belts and specialty systems which demand specific splicing configurations. To a large extent, almost every conveyor belt installation must be evaluated to determine which vulcanizing method is most suitable. Due to the multitude of vulcanization methods used, this article will be restricted to very general considerations.
The first factor to be considered for the conveyor belt vulcanizing process is the belt itself. This will determine the minimum splice requirement. Once the belt specifications are known, the proper cements, rubber, and breaker fabric can be determined. The actual splice layout should be determined by following the belt manufacturer's and system designer's recommendations. It is important to remember that the system design may require a more involved splice than that generally required by the belt manufacturer. An example of this is with steeply inclined systems with a sharp bend at the upper elevation. Frequently, an extra-long step length for fabric belts or a longer splice length for steel cable belts should be used to counter the extra forces placed on the belt at this point.
The main vulcanization techniques to be considered for multi-ply fabric carcass belts include belt squaring to ensure a straight splice; material choice to ensure compatibility and strength; and step length to ensure proper splice strength. With some systems, the bias angle of the splice is important. Some systems require a 45° bias angle while others require less of an angle or no bias at all. It is mandatory to determine the splice requirements for the belt before starting.