Bucket Elevator

Equipment Introduction

A bucket elevator, also known as a chain bucket elevator, multi-bucket elevator, or bucket lift, is a conveying machine that uses a series of buckets uniformly fixed to an endless traction component to continuously transport powdery, granular, and small lump bulk materials vertically or nearly vertically. It is a typical continuous conveying device for bulk materials, playing a crucial role in industrial production by connecting upstream and downstream processes and running the production line smoothly.

Bucket elevators are indispensable vertical conveying equipment in fertilizer production lines, feed processing plants, grain storage facilities, and other similar settings. Their core advantages lie in their small footprint, large lifting height, stable conveying capacity, and good sealing performance. The equipment can be customized to meet different material characteristics and process requirements by using different traction components (such as belts, ring chains, and plate chains) and bucket types, resulting in multiple series such as TD, TH, and NE.

This equipment is widely used in building materials, mining, chemical, grain, feed, power, metallurgy, and light industry sectors. The drive unit is usually located at the top of the elevator. It transmits power to the traction components through components such as electric motors and reducers to achieve continuous vertical lifting of materials.

Equipment Structure and Components

The bucket elevator mainly consists of the following core components:

1. Traction Components and Buckets

1) Belt (TD type): Uses rubber belts or steel wire rope core belts, suitable for light, non-high-temperature materials, with smooth operation and low noise.

2) Circular Link Chain (TH type): Uses high-quality alloy steel forged link chains, suitable for moderately abrasive materials, with a temperature resistance up to 250°C.

3) Plate Chain (NE type): Uses high-strength alloy steel plate chains, with high load-bearing capacity and strong wear resistance, suitable for heavy-duty and high-temperature conditions (up to 400°C).

4) Buckets: Divided by depth into shallow buckets (suitable for powdery, easily agglomerated materials) and deep buckets (suitable for granular, free-flowing materials), fixed to the traction components by bolts.

2. Upper Section (Head Unit)

Includes drive rollers/sprockets, discharge port, bearing seats, drive unit, and backstop brake. The drive unit typically consists of a motor and a reducer, and the backstop prevents material backflow in case of sudden shutdown.

3. Lower Section (Base)

Includes the tail pulley/tensioning roller, feed inlet, and tensioning device. The lower section typically uses a counterweight box for constant force automatic tensioning or a screw tensioning system to maintain constant tension in the traction components, prevent slippage, and provide cushioning protection in case of hopper jamming.

4. Intermediate Casing

Composed of standard sections, this section uses angle steel and steel plates welded into a fully enclosed structure. It features inspection doors and observation windows to prevent dust from escaping and facilitate maintenance.

Raw Materials for the Equipment

Bucket elevators are suitable for conveying various forms of bulk materials, but must meet the following basic conditions:

1. Form: Powdered, granular, and small lump materials are best suited, such as fertilizer granules, organic fertilizer powder, coal, sand, cement, crushed ore, and grain.

2. Bulk Density: Generally suitable for materials with a loose density ρ < 1.5 t/m³.

3. Temperature: TD belt type typically requires a material temperature ≤ 60°C (rubber belts have limited temperature resistance); TH ring chain type can reach 250°C; NE plate chain type can adapt to high-temperature materials up to 400°C.

4. Unsuitable Materials: Wet sludge, highly viscous materials, materials prone to severe agglomeration, and oversized, sharp, and highly abrasive rocks (which must be crushed first).

Working Principle of the Equipment

The working principle of a bucket elevator mainly consists of four continuous stages: loading, lifting, unloading, and empty bucket return.

1. Loading (Feeding): Material enters from the feed inlet at the bottom of the equipment and is loaded into the buckets using either a scooping or inflow method. Scooping is suitable for powdery or granular materials, where the buckets directly scoop up material as they pass through the bottom storage area; inflow is suitable for lumpy or abrasive materials, where the material flows directly into the buckets.

2. Lifting: The buckets, filled with material, are driven by a traction component (belt or chain) to move upwards at a constant speed along the ascending channel within the enclosed casing. The entire process is continuous.

3. Unloading After the hopper is lifted to the top and passes the head wheel, it is thrown into the discharge port in one of three ways, depending on the material characteristics and equipment type:

1) Centrifugal unloading: Utilizing centrifugal force to throw the material out; suitable for dry, free-flowing powdery or granular materials.

2) Gravity unloading: The material slides down under its own weight; suitable for lumpy, abrasive, or moist materials.

3) Mixed unloading: A combination of both.

4. Empty Hopper Return After unloading, the empty hopper continues to be carried by the traction component around the top and returns to the bottom along the descending channel (unloaded branch), re-entering the loading area. This cycle repeats continuously, achieving continuous vertical conveying.

The entire process is completed within a sealed casing, effectively preventing dust leakage.

Applications of Bucket Elevators

Bucket elevators have extremely wide applications and are indispensable vertical conveying equipment in modern industrial production:

1. Fertilizer and Organic Fertilizer Industry: Bucket elevators are core vertical conveying equipment connecting various processes in organic fertilizer, compound fertilizer, and BB fertilizer production lines. They are used for the vertical conveying of crushed raw materials, mixed ingredients, granulated particles, and dried and cooled finished products between different equipment. In the organic fertilizer production process, bucket elevators are responsible for lifting materials from a lower level to a higher level for the next process.

2. Grain Processing and Storage: Used for the vertical conveying and storage of materials such as grains, cereals, and flour.

3. Feed Processing: Used for the vertical conveying of various powdery and granular raw materials and finished products in feed mills.

4. Mining and Metallurgy: Used for the lifting and conveying of materials such as ores, coal, and crushed ore.

5. Building Materials and Cement: Used for conveying building material raw materials such as cement, sand, coke dust, limestone, and dry clay.

6. Chemical and Power Industries: Used for the vertical transport of materials such as fertilizers, chemical raw materials, and coal. Bucket elevators can lift almost all bulk materials.

Equipment demand groups

Bucket elevators are intended for all industrial users who need vertical bulk material transportation, mainly including:

1. Fertilizer production enterprises: organic fertilizer factory, compound fertilizer factory, BB fertilizer factory, high-tower fertilizer factory, used for vertical transportation of raw materials and finished products.

2. Grain and feed processing enterprises: upgrading and warehousing of grain drying lines and feed processing lines.

3. Cement and building materials companies: efficient warehousing of raw materials, clinker, and finished cement products.

4. Chemical and mining enterprises: vertical transportation of granular and powdery chemical raw materials and ores.

5. Port and logistics warehousing: loading, unloading and silo stacking of bulk materials.

Common Faults, Causes, and Standardized Solutions

Application of Equipment in Production Lines

1. Core Position in Organic Fertilizer and Compost Production Lines

The bucket elevator is the vertical conveying link throughout the entire fertilizer production line. Its performance directly determines the continuity and efficiency of the entire production line.

Location in the complete processing flow:

Raw material pretreatment → Bucket elevator → Crushing → Bucket elevator → Batching and mixing → Bucket elevator → Granulation → Bucket elevator → Drying → Bucket elevator → Cooling → Bucket elevator → Screening → Bucket elevator → Coating → Bucket elevator → Packaging

2. Specific role in the production line

Process connection: Elevates materials from lower equipment to higher equipment, realizing a three-dimensional workshop layout.

Continuous production: Supports 24-hour continuous and stable operation, ensuring uninterrupted production line operation.

Land saving: Vertical conveying significantly reduces the floor space occupied by horizontal conveying equipment.

Sealed conveying: The sealed casing prevents material dust from flying, improving the working environment.

3. Special requirements in organic fertilizer production

Bucket elevators for organic fertilizer production need to be specially designed for material characteristics:

Using rolling components on the buckets to strike the buckets, improving material discharge efficiency.

Utilizing the inclined guard plate structure at the bottom of the buckets to reduce material accumulation at the bottom of the casing, solving the blockage problem.

Equipped with a vibration damping base to eliminate operating vibration.

4. Automated Control: Modern bucket elevators support optional sensors for misalignment, temperature, and stall detection, providing a foundation for remote monitoring and intelligent early warning. Key components such as the drive motor can be explosion-proof, and a casing with explosion-proof function is optional.

Bucket elevators are an irreplaceable core piece of vertical conveying equipment in modern bulk material handling systems. Through the coordinated circulation of buckets, traction components, and rollers/sprockets, they achieve continuous lifting of large quantities and high heights with a minimal footprint. In fertilizer production lines, they connect various height-difference nodes from raw material warehousing to finished product packaging, serving as crucial equipment for ensuring the automated and continuous operation of the entire line. Proper selection (TD/TH/NE), maintaining uniform feeding, and implementing regular tensioning and lubrication maintenance are fundamental guarantees for ensuring long-term stable operation and a trouble-free lifespan of over 20,000 hours.