Effective belt conveyor maintenance for concrete producers has two key goals, both with bottom line consequences. The first is to prevent surprise belt failures. The second is to minimize repair downtime.

While all aspects of conveyor system maintenance are important, belt splicing is among the most critical. Its impact on maintenance is unquestionable. It's one of the few components that constantly receives heavy, abrasive wear. Also, when a splice fails, it not only stops operation and causes downtime, it results in material loss. Sometimes the resulting cleanup is worse and more costly than the repair itself.

Mechanical fasteners and vulcanization are the two primary methods for joining the ends of conveyor and elevator belts. Although vulcanized splicing is preferred in some locations, mechanical splicing has become more popular as it continues to prove its value as a cost-reducing, uptime increasing alternative.

Factors favoring fasteners

Technological advances in mechanical belt fasteners and systems have fueled this development.

These developments include belts made of newer synthetic materials, improving mechanical fastener designs, newer alloys that resist abrasion and corrosion, and new tools that recess fasteners for smoother and quieter operation.

At the same time, some commonly held beliefs about vulcanization have been scrutinized and questioned. For example, the old saying that a vulcanized splice is as strong as the original belt is false. A two-ply belt can lose about half of its strength when vulcanized, while a three-ply belt can lose one-third.

Vulcanizing works best on new belting. On older worn belts, where most emergency splicing is done, vulcanizing often becomes difficult to do properly, and is less reliable than a mechanical splice.

It is also true that vulcanized splices deteriorate from within, making it difficult to detect potential problems and increasing the potential for surprise failures. Mechanical splices will show signs of wear and damage, enabling splice repairs to be performed as part of scheduled downtime.

The materials used to vulcanize the splice—the adhesives and rubber compounds—must be kept up-to-date and properly stored. Using products that are out-of-date will give less than optimum results that cause the vulcanized splice to fail prematurely.

Mechanical splices have no restrictions as to their shelf life or storage conditions. Splicing components that were made several years ago are just as good as those that were made yesterday.

Saving time and money

A mechanical splice can be installed faster and easier than a vulcanized splice. It takes several hours to complete a vulcanized splice. The crew must cut a belt back, trim the steps, and fit the belt ends together. Other time-consuming steps include applying the appropriate compounds, cooking the belt under heat and pressure, and allowing the belt to cool.

The total cost for the vulcanized splice will be several thousand dollars, not including the cost of the vulcanizing presses. This does not take into account the additional downtime waiting for the vulcanizing crew to travel to and set up at your site. The amount of belting used to splice a 48-inch-wide belt can be 72 inches or more, and it can require six to eight hours to complete.