Tail Bend Pulley (often referred to as "direction-changing drum" or "guide drum" in Chinese) is a key component in belt conveyor systems. Its main functions are to change the running direction of the conveyor belt and optimize the contact angle with the drive drum, ensuring the stability and efficiency of the conveying process. The following is a detailed overview:
Core Functions and Roles
Direction Control: As a core component at the tail of the conveyor, the Tail Bend Pulley enables the conveyor belt to form a closed-loop cycle through physical redirection, transporting materials from the discharge end back to the feeding end. For example, in long-distance conveying in mines or ports, it can guide the belt around curved paths, avoiding uneven tension caused by excessively long straight sections.
Enhancing Transmission Efficiency: By pressing the conveyor belt, the Tail Bend Pulley can increase the wrap angle (contact area) with the head pulley, thereby improving friction and reducing the risk of belt slippage. For instance, in humid or dusty environments, direction-changing drums with rubber or ceramic coating can significantly enhance transmission reliability.
Auxiliary Tensioning: In some designs, the Tail Bend Pulley cooperates with tensioning devices to fine-tune the belt tension by adjusting its position, ensuring the belt is always in optimal working condition.
Structure and Material Design
Basic Structure: A direction-changing drum typically consists of four parts: shaft, bearing housing, web, and cylinder. The cylinder is made of seamless steel pipe or welded structure, and its surface can be covered with materials such as rubber or ceramic to enhance wear resistance and friction. For example, ceramic coating can extend the drum's service life by 10 times, making it suitable for high-wear environments.
Bearings and Lubrication: Spherical roller bearings are mostly used in the bearing housing, allowing a certain angle of deviation to ensure the drum rotates flexibly even under complex working conditions. Regular addition of lithium-based grease is a key maintenance step.
Classification and Specifications: Classified by load capacity into light, medium, and heavy types. Light-type: bearing bore diameter 50-100mm, suitable for small conveyors; medium-type: bore diameter 120-180mm, common in general industrial scenarios; heavy-type: bore diameter 200-260mm, used in heavy-load environments such as mines.
Application Scenarios
Industrial Fields: Widely used in mines, ports, power plants, cement factories, etc. For example, in coal conveying, direction-changing drums can guide the belt around obstacles while withstanding the impact of large materials.
Adaptability to Special Environments: In high humidity or muddy environments, sealed designs and corrosion-resistant materials (such as stainless steel) can prevent component rust; in dusty environments, the compact structure reduces material accumulation, ensuring long-term stable operation.
New Designs: Some direction-changing drums adopt adjustable tail pulley technology (such as patented designs), which dynamically adjusts the belt position through mechanical or hydraulic devices to reduce deviation and wear.
Maintenance and Common Issues
Regular Inspections: Check rotational flexibility, bearing temperature, and belt deviation; clean and lubricate by removing adhered materials on the drum surface and replenishing lubricant every 500 operating hours.
Typical Faults and Countermeasures: Material entrapment: materials stuck between the belt and the drum may cause belt tearing or drum damage, requiring the installation of scrapers or anti-entrapment devices; wearing of the coating: timely replacement of severely worn coating layers to avoid direct metal contact leading to slippage.
Tail Bend Pulley is the "steering hub" of the belt conveyor system, and its design directly affects conveying efficiency and equipment service life. By selecting appropriately (such as using ceramic coating for high wear) and conducting regular maintenance (such as lubrication and cleaning), its performance can be maximized. With the development of industrial automation, innovative designs such as adjustable tail pulleys have further improved its adaptability, enabling it to continue playing a core role in modern material handling.
