What a Bend Pulley Assembly Does
A bend pulley assembly is a key component in a belt conveyor, used to change the direction of the conveyor belt or to increase the wrap angle around the drive pulley. Unlike the drive pulley that transmits power, or the tail pulley that provides tension, the bend pulley is typically an idler pulley that guides the belt along its return path. It is often found at the head, tail, or tensioning section of the conveyor. In industries such as mining, cement plants, power stations, and aggregate yards, the bend pulley helps maintain proper belt tracking and tension.
Construction and Key Components
A typical bend pulley assembly consists of a cylindrical shell, shaft, bearings, and bearing housings. The shell can be smooth or covered with rubber, ceramic, or other materials to improve grip and wear resistance. Common surface options include plain, rubber lagging (cold-bonded or hot-vulcanized), diamond grooved, herringbone, and ceramic lagging. Lagging thickness often ranges from 8 mm to 20 mm depending on the application. The shaft diameter is determined by torque and load requirements, with common sizes including Ø50, Ø60, Ø70, Ø80, Ø90, Ø100, Ø120, Ø140, Ø160, Ø180, and Ø200 mm. The pulley diameter varies with belt width and tension needs; typical diameters are Ø200, Ø250, Ø315, Ø400, Ø500, Ø630, Ø800, Ø1000, Ø1250, Ø1400, Ø1600, and Ø1800 mm. Belt widths from B400 to B2400 are common, and the pulley face width is usually slightly wider than the belt, for example, B800 belt may use a pulley face of about 950 mm. The assembly is mounted on a conveyor bracket or frame and works in conjunction with idler rollers and the conveyor belt.
Where It Is Used
Bend pulley assemblies are essential in many bulk material handling systems. In a coal preparation plant, they help route the conveyor belt around corners and maintain tension. In a limestone quarry or sand and gravel line, they ensure smooth operation of the conveyor belt, especially in dusty and abrasive conditions. In power plant coal handling, cement clinker transport, and port bulk terminals, the bend pulley contributes to reliable belt training and extended belt life. They are also found in tunneling muck removal, fertilizer plants, and grain silos.
Selection and Maintenance Tips
When choosing a bend pulley assembly, consider the belt width, required diameter, shaft load, and environmental conditions. The pulley diameter should be large enough to avoid excessive belt bending stress, but there is no fixed rule that one belt width matches only one diameter. For abrasive materials, lagging such as rubber or ceramic can prolong service life. The shaft diameter must be calculated based on the actual torque and radial load, not simply derived from belt width. Regular maintenance includes checking bearing condition, lagging wear, and alignment. Proper installation with the correct conveyor bracket ensures optimal performance. Keep the pulley clean and ensure the belt runs centered to prevent edge damage.
Common Specifications (Reference)
The following table lists typical parameters for bend pulley assemblies. These are for reference only and should be confirmed with the manufacturer for each application.
| Parameter | Common Values |
|---|---|
| Belt width (B) | B400, B500, B650, B800, B1000, B1200, B1400, B1600, B1800, B2000, B2200, B2400 |
| Pulley diameter | Ø200, Ø250, Ø315, Ø320, Ø400, Ø500, Ø630, Ø800, Ø1000, Ø1250, Ø1400, Ø1600, Ø1800 |
| Pulley face width | Usually greater than belt width, e.g., B400 ~500 mm, B800 ~950 mm, B1200 ~1400 mm |
| Shaft diameter | Ø50, Ø60, Ø70, Ø80, Ø90, Ø100, Ø120, Ø140, Ø160, Ø180, Ø200 |
| Surface type | Plain, rubber lagging (cold-bonded or hot-vulcanized), diamond grooved, herringbone, ceramic lagging |
| Lagging thickness | 8, 10, 12, 15, 20 mm |
Note: The above values are typical and not mandatory for every conveyor. Actual selection should be based on engineering calculations and application requirements.
