Belt Maintenance: Successful Conveying for Maximum Efficiency

March 6, 2009

Conveyor belt breakdowns can be damaging to customer confidence, as well as to the reputations of airports and airlines alike. Plus, repair times can be lengthy and costly. Proper selection and preventive maintenance practices form the best combination for productive, effective, and economical baggage handling operations. This involves a careful analysis of belt splicing methods, proper selection of fasteners, and the use of several portable installation tools.

Belt splicing practices
Proper belt splicing is often the most critical aspect of conveyor system maintenance. The conveyor belt is one of the few components that receive regular, heavy wear.

There are two basic methods — vulcanization and mechanical fasteners — to connect conveyor belt ends together. Vulcanization is the process of fabricating two belt ends together, using heat or chemical activation, to make the belt a continuous, endless length. Mechanical fasteners, on the other hand, physically attach a row of fasteners to each belt end. The fasteners are then meshed together and connected with a hinge pin. An increasing number of large international airports, including Chicago’s O’Hare International Airport, the Dubai International Airport in Bangkok, and Sydney International Airports, have selected and relied upon mechanical fasteners for efficient conveyor belt operation.

Mechanical Fasteners vs. Vulcanization
Mechanical fasteners offer distinct advantages when it comes to fast, reliable repairs. They are easy to install and require only basic mechanical skills for maintenance personnel. Unlike vulcanized splices, the wear on the splice is visually apparent, allowing maintenance crews to complete a repair during scheduled downtime. Because the splices are hinged or separable, they can be installed or replaced quickly and economically without having to disassemble the conveyor system or remove the belt from the conveyor structure.

Vulcanized splices operate quietly, do not mark the conveyed product, and provide a strong, long lasting splice. At the same time, they take considerably longer and cost substantially more than mechanical fasteners to install and repair. Often, contracted, skilled installation personnel and expensive equipment are needed. Even if spare belts are kept on hand for emergency use, repairs require additional downtime while the conveyor structure is partially disassembled during belt installation. A vulcanized splice can take from six to eight hours to complete, once an installation crew arrives. The process involves cutting, trimming and fitting belt ends as well as applying appropriate compounds, cooking the belt under heat and pressure, and allowing the belt to cool. Mechanical splices, on the other hand, involve only a few inches of the belt. Typically, a reliable mechanical splice can be installed by one person in approximately 20 minutes, start to finish.

Fastener Selection
Suitable mechanical fasteners come in a broad variety of shapes and sizes. Each is designed with a common purpose — to maintain top productivity. Different compositions and styled fasteners make selection an important overall consideration. The specific application and working environment generally dictate which fastener is best.

For baggage belt loading systems, generally 24" (600 mm) wide, wire hooks offer a low-profile, yet strong splice with minimal wear on conveyor components and the baggage being conveyed. They are also compatible with conveyor components and compliant with the need to reduce operating noise. They are available in a variety of wire diameters, leg and point lengths, strip lengths and styles. When used with specially designed lacers they provide a precise, strong and smooth splice. Clipper® Wire Hooks, for example, are designed for belt thicknesses ranging from 3/64" to 25/64" (1.2 mm to 10 mm). The recommended maximum operating tension is up to 200 P.I.W. (35 kN/m) and minimum pulley diameter is 5/16" to 7" (24 mm to 175 mm).

Because of their overall strength and resistance to impact damage, staple/plate fasteners can also be used effectively on baggage belt loading systems. They provide exceptional holding power without degrading the integrity of the belt carcass. Staple fastening systems also provide a reliable splice that is fast and easy to install. The Alligator® Ready Set™ staple fastener system features one-piece fastener strips with pre-inserted staples that reduce installation time by eliminating the need for handling and loading individual staples. Available in a variety of styles and materials, they are designed for belts from 1/16" (1.5 mm) to 1/4" (6.4 mm).

The recommended maximum operating tension is up to 200 P.I.W. (35 kN/m) and recommended minimum pulley diameter is 2" to 4" (50 mm to 100 mm).

Proper Installation
Good installation practices affect both the splice life and belt performance, so do proper repair and maintenance procedures. Having the right tools on hand and applying basic belt repair safety guidelines will speed and simplify repairs and lead to strong, consistent splices.

Proper installation begins with precision belt cutting. Portable, lightweight belt cutters make it easier to achieve straighter, squarer cuts and to do so more uniformly and safely. With belt ends properly squared, the problems associated with mistracking, including premature belt wear, splice wear, and fastener pullouts, are less likely to occur. Today’s belt cutters are sized for a range of belt thicknesses and widths. For example, the Clipper® 845LD belt cutter from Flexco has been designed for belts up to ½" (12 mm) thick and are available in four widths: 36", 48", 60", 72" (900, 1200, 1500, 1800 mm). The cutter was designed to provide a safe method to cut belts, a process, which is otherwise dangerous and often results in injuries. The fully enclosed blade provides a straight and perpendicular cut, which will allow the spliced belt to run straight and avoid unnecessary belt mistracking.

Once the belt cutters have achieved straight, square cuts, portable installation tools are used to install the fasteners. Flexco has engineered a wide variety of installation tools for an optimally installed splice with minimal effort and time required for installation. Two examples of this include the Clipper® Roller Lacer® Gold Class™ and the Alligator® Staple Quad Driver.

The Roller Lacer Gold Class employs the time proven Roller Lacing Technology™ for installing Clipper® wire hooks with new features to reduce operator fatigue and installation time. Some of these improvements include the ability to drive the lacer head with a cordless drill and the integrated belt support shelf. The Alligator Staple Quad Driver simplifies installation by simultaneously applying four staples vs. the conventional driver, which only installed two staples at a time.

Keeping instruments like these readily available will help maintenance personnel safely respond to unanticipated belt downtime, efficiently from a time standpoint, and effectively in terms of lasting repairs.

To learn more about mechanical belt fastening systems specifically engineered for the airport baggage handling industry, access