Belt conveyors – Construction, conveying capacity and belt selection for optimized processes

Belt conveyors are versatile conveyor systems that play a critical role for optimizing industrial production processes. From its basic design to the various types of drives to the capacity of the conveyor, this blog highlights how to get the most out of your conveyor. We will also take a look at the different belt shapes used on belt conveyors and will show you what to look for when replacing the belts to ensure smooth operation in your industrial plant.

What are belt conveyors?

Belt conveyors are a core technology in today’s material handling equipment and form an essential part of efficient material transport systems. As one of the most commonly used conveying methods, they are used in numerous industries to convey materials reliably and continuously from one point to the other. Whether in logistics or in heavy industry, belt conveyors offer a flexible and cost-efficient solution for horizontal and inclined transport of bulk and discrete goods. As part of the broader category of conveyors, belt conveyors are characterized by their versatility and adaptability, as they can be used for light as well as heavy loads and over short or long distances. They provide a critical foundation for automating and optimizing material flows in dynamic production environments and help to make operations more efficient and productive.

Basic construction of belt conveyors

Belt conveyors essentially consist of a continuously revolving belt or strap that runs on two or more drums. One of the drums is equipped with a drive that moves the belt while the other drums act as deflection rollers. The belt transports materials or goods from one point to another, either horizontally or at an incline. Belt conveyors impress with their simple construction, versatility and efficiency, especially in the form of a modular conveyor. They therefore represent a flexible and cost-effective solution for transporting materials and products that are suitable for different requirements.

(1) protective cover, (2) belt deflection roller, (3) conveyor belt, (4) profile frame, (5) protective cover drive, (6) drive

Drives, conveying capacity and belt shapes of belt conveyors

When selecting a belt conveyor, different aspects and parameters must be taken into account, including Drive type, conveying capacity and belt shape. The drive determines how powerfully and reliably the conveyor operates, while the capacity of the conveyor indicates how much material can be transported over a certain period of time. The belt shape in turn not only affects the hold of the conveyed goods, but also the suitability for special transport requirements, such as use on inclined paths or for precise positioning.

Drive types of belt conveyors

A conveyor belt is set in motion by various drive types, wherein the gearbox ensures the power transmission between the motor and the drive drum. Depending on the application, different drive solutions such as the head drive, center drive or internal drives are used, each of which offers specific advantages for the efficiency and space use of the system.

For the head drive (1), the drive unit is located at the end of the conveyor in conveying direction. The motor drives a drive drum, which pulls the belt over the conveyor. The head drive is the most commonly used drive form and is used in single-track and also in multi-track systems. For the central drive (2), the drive unit is positioned centrally below the conveyor belt. The motor drives one or more drums, which can pull or push the belt in both directions. This drive form provides better load distribution because the belt is moved from the center and the conveyed goods are distributed evenly. The internal drive (3), also called an integrated drive, is a relatively compact drive solution on which the motor is integrated directly into the drum. The drive is completely hidden inside the system, providing a space-saving design. This type of drive is often used on conveyors in confined environments where space is limited for separate motors and drive units.

Conveying capacity of belt conveyors

The conveying capacity is the amount of material that a conveyor belt can transport in a certain time. It is crucial for the efficiency of the entire material flow and depends on several criteria that must be coordinated with one another to achieve maximum performance.

The width of the conveyor belt is an essential aspect for calculating the conveying capacity. This determines how much space the material has on the conveyor belt and therefore significantly influences how much material can be conveyed at a time. A wider conveyor belt permits transporting larger or more voluminous goods, while narrower belts are used for smaller or standardized products. Another important point is the belt tension, which ensures that the belt is tight enough to run reliably without sagging or slipping.

Belt speed is yet another important aspect. The faster the conveyor belt runs, the more material can be transported in a certain time. However, the conveyor speed must be adjusted to the type of material being conveyed and to the environment, as sensitive or sluggish materials could be damaged or transported unsafely at excessive speeds. This is where the maximum speed of the conveyor belt comes into play. It represents the upper limit for how fast the belt can be operated without jeopardizing the safety or integrity of the transported materials.

Belt shapes of belt conveyors

Belt conveyors are characterized by their flexibility and adaptability to different transport requirements. On a belt conveyor, a continuous belt or strap transports discrete goods or bulk goods from one point to another. Various belt options that determine the functionality and performance of the conveyor belt are available, depending on the application and the conveyed material.

(1) Conveyors with flat belts or a flat conveyor belt are characterized by their simple construction and high efficiency. Flat belts consist of materials such as polyurethane (PU), PVC or rubber and provide a smooth, continuous surface on which the conveyed goods are transported. Pulleys for flat belts play an important role for smooth operation as they transfer power from the motor to the belt. Flat belt conveyors are ideal for transporting light to medium weight goods in different industries and provide a flexible and reliable solution for various applications.

(2) Synchronous belt conveyors are characterized by teeth on the inside of the belt that engage into teeth on the driven pulleys. This ensures a slip-free power transmission. This positive power transmission allows synchronous belt conveyors to perform very precise and uniform movements without the synchronous belt slipping or stretching. Synchronous belt conveyors are used in applications where precise synchronization is of great importance, such as CNC machines or workpiece positioning.

(3) As the name suggests, round belts have a round cross section made of materials such as polyurethane (PU) or rubber. They are often used in applications that transport light goods or small products, or in situations with limited space for the conveyor system. Round belt conveyors are often more flexible and can handle tight bends, making them ideal for complicated conveyance paths that cannot be easily addressed by flat conveyor belts.

Replacing the belts of belt conveyors

When replacing belts of belt conveyors, there are some important aspects to consider to ensure smooth and safe operation. This includes, among other things, the correct direction of rotation of the belt since incorrect alignment can compromise system efficiency and cause premature belt wear. Another important point is to adjust belt drift to ensure that the belt runs centered on the rollers and does not drift laterally, which could lead to damage.

The procedure also differs depending on the drive type of the conveyor. For head-drive conveyors, the belt is usually installed and tensioned from the drive end, whereas a more uniform tension distribution is required for center drives to correctly center the belt and balance the load on both sides. In both cases, it is essential to change the belt precisely and according to the manufacturer's specific instructions to ensure the durability of the system.

After replacing the belt on a belt conveyor, it is important to carefully check the belt tension with a belt tension gauge and to adjust it as needed. Correct tension ensures that the belt runs smoothly and efficiently without slipping or sagging. Insufficient tension can result in slippage and uneven movements, whereas excessive tension can unnecessarily stress the belt and mechanical components and cause premature wear.