Bucket Elevator
A bucket elevator is a type of continuous conveying machinery designed to lift materials vertically using a series of buckets uniformly attached to an endless traction element. By securing these buckets to a traction chain or belt, the equipment transports bulk materials upward in a vertical or near-vertical direction. As core equipment for vertical material transport in industrial production, bucket elevators are widely used across sectors such as mining, metallurgy, coal, electric power, ports, chemicals, building materials, grain processing, and fertilizer manufacturing.
Bucket elevators are ideal for lifting materials from lower to higher elevations; once material is fed into the buckets via a vibrating feeder, the machine operates automatically and continuously to transport the load upward. Conveying speed can be adjusted based on throughput requirements, and the lifting height can be customized to specific needs. These elevators offer significant advantages, including high conveying capacity, substantial lifting height, smooth and reliable operation, and a long service life. They are available in three main configurations: round-link chain, plate-link chain, and belt-driven types.
In fertilizer manufacturing, bucket elevators perform the critical task of vertical material transport and are commonly used in the production of compound, organic, bio-based, and controlled-release fertilizers. Capable of transporting materials vertically from low to high points while maintaining a compact footprint and achieving significant lifting heights, this equipment is an indispensable component of fertilizer production lines.
Structural composition of the equipment
A complete bucket elevator consists primarily of the following core components:
(I) Traction Element: The core component that drives the continuous circulation of the buckets; it comes in two types: rubber belts and chains. Rubber belts are fastened to the buckets using screws and elastic washers, with the belt being 35–40 mm wider than the buckets; standard belts handle materials up to 60°C, while heat-resistant belts can handle materials up to 150°C. Chains come in single-strand and double-strand configurations—single chains attach to the rear wall of the bucket, while double chains connect to both sides.
(II) Buckets: Containers that hold the material; various bucket styles can be selected based on material characteristics and conveying requirements. Materials such as non-toxic PP (polypropylene) may be used, and all dimensions are designed and manufactured according to specific needs.
(III) Drive Unit: Comprising the motor, gearbox, drive shaft, etc., located at either the top or bottom of the elevator. Once activated, the drive unit moves the traction element to circulate the buckets.
(IV) Head and Tail Wheels: Including the top pulley (or sprocket) and bottom pulley (or sprocket). The top pulley acts as the drive pulley, connecting to the drive unit to transmit power; the bottom pulley acts as the redirecting (or tail) pulley, changing the direction of the traction element.
(V) Tensioning Device: Used to adjust the tension of the traction element, ensuring sufficient friction between the bucket belt and the head wheel. Types include screw-type and gravity-type tensioners.
(VI) Casing (Trunking): Comprising the upper section (head), middle section (trunking), and lower section (boot/base). The casing forms an enclosed structure to prevent dust emissions. The upper section features an inspection door and discharge outlet, while the lower section includes an inlet and an inspection port.
(VII) Backstop (Anti-reverse) Device: Installed on the drive unit to prevent the elevator from reversing direction during a sudden shutdown. For tall elevators (over 20 meters), it prevents material backflow that could cause clogging.
Application scope of the equipment
Bucket elevators have a wide range of applications. In fertilizer production, they are commonly used to convey materials such as compound fertilizers, organic fertilizers, bio-fertilizers, and controlled-release fertilizers; specifically, they handle the vertical lifting of both raw materials and finished products. In the mining and metallurgy sectors, they are suitable for transporting materials such as ore, coal, cement, crushed stone, sand, and clay. In the grain and food industries, they are used to convey grain, cereals, and animal feed. In the construction materials and chemical industries, they handle materials such as cement, chemical fertilizers, and chemical raw materials. In the environmental protection and power sectors, they are suitable for transporting materials like fly ash and desulfurization gypsum.
Types of usable raw materials
Bucket elevators are capable of conveying a wide variety of materials. The equipment is suitable for transporting powdery, granular, and small-lump materials that are non-abrasive or have low abrasiveness. Specific examples include: fertilizer raw materials (compound fertilizer granules, organic fertilizer granules, NPK fertilizer, animal manure, etc.); grains (wheat, corn, paddy rice, cereals, etc.); minerals (coal, cement, crushed stone, sand, clay, ore, etc.); and chemical products (chemical fertilizers, chemical powders, etc.). Material temperatures generally do not exceed 250°C; for belt-type conveyors, the limit is typically 60°C (or up to 150°C with heat-resistant belts).
The working principle of the equipment
The basic operating principle of a bucket elevator is as follows: buckets scoop up material or receive it via inflow at the bottom storage area, rise to the top driven by the traction mechanism, pass over the head pulley, and discharge the material into a receiving chute using centrifugal force, gravity, or a combination of both. The entire process typically takes place within an enclosed casing to prevent dust leakage.
The operational workflow consists of four continuous stages: the loading stage, where buckets scoop up or receive material at the bottom inlet; the lifting stage, where the traction mechanism drives the loaded buckets vertically to the top; the discharging stage, where buckets invert after passing over the head pulley and dump the material into the receiving chute via centrifugal force, gravity, or a combination of both; and the empty bucket return stage, where the emptied buckets travel back down to the bottom to be refilled and lifted again, creating a continuous cycle for the vertical transport of material.
Equipment operating instructions
(I) Pre-start Preparation: Conduct a comprehensive inspection before operation. Check for any loose or missing fastening bolts and assembly bolts. Inspect the interior of the bucket elevator for foreign objects, material buildup, or accumulated water. Verify that all lubricants meet specifications. Confirm the anti-reverse device is intact. Ensure the material to be conveyed complies with equipment requirements. Confirm all safety guards are in good condition. Perform a manual rotation (inching) to ensure there are no abnormalities before proceeding to a trial run.
(II) Startup Sequence: Start the discharge equipment first, then the bucket elevator. The elevator must be started under no-load conditions. Once the elevator is running stably without a load, slowly open the feed gate and gradually increase the feed rate. Strictly adhere to the principle of "start without load, stop without load."
(III) Operational Monitoring: Ensure uniform feeding during operation to avoid overloading. Observe the elevator for any swaying or impact and assess the tension of the chain plates. Monitor lubrication and temperature rise across various components. Do not open the head casing or remove the base slide plate during normal operation. Do not open manhole doors or inspection ports while the machine is running.
(IV) Shutdown Procedure: Stop the material feed first. Once all material has cleared, press the elevator stop button and cut off the power supply. Ensure the elevator is completely empty of material before shutting it down. Starting under load is strictly prohibited.
