A bucket elevator, also known as a grain leg, is a piece of equipment used prominently in the agricultural, road construction, and mining industries to elevate bulk material. ^[1][2][3]

Contents 1 How it Works 2 Types 2.1 Centrifugal Bucket Elevator 2.2 Continuous Bucket Elevator 2.3 Positive Discharge Bucket Elevator 2.4 Internal Discharge Bucket Elevator 3 Common Manufacturers 4 References

[edit] How it Works

A bucket elevator works by connecting many buckets via chains or a conveyor belt around a powered pulley system. The buckets are first filled with bulk material at the bottom of the elevator. Then the buckets ascend the elevator ramp, until they reach the very top where the material is discharged.^[4]  The buckets are designed to stay upright to prevent spillage.^[5]

[edit] Types

[edit] Centrifugal Bucket Elevator

A centrifugal bucket elevator operates by rotating at a rapid pace which causes material to be discharged at the top of the elevator via centrifugal force. These elevators typically operate at a speed between 4.3 and 11.5 feet (1.3 and 3.5 m) per second and have buckets that are widely spaced out. They are meant for use with fine granular material because the speed of rotation is too quick for lumpy materials. Centrifugal elevators are loaded by a combination of direct flow and scooping; when material is fed to the bottom of the elevator, some of the grain goes directly into buckets, the rest falls to the bottom of the elevator. When buckets reach the bottom of their rotation they scoop up material from the bottom of the elevator.^[6][7][8]

[edit] Continuous Bucket Elevator

Continuous bucket elevators are gentler than centrifugal elevators because they operate at lower speeds; between 3.3 and 4.3 ft (1.0 and 1.3 m) per second. They are used to handle finely composed materials, or light fluffy material which must not be aerated. Continuous bucket elevators are fed by direct flow only. There are virtually no gaps between buckets to prevent material from spilling out and to increase the amount of material being processed per rotation. Continuous bucket elevators are typically assembled vertically, however they can also be assembled horizontally or on an angle to facilitate bulky materials.^[9][10]

[edit] Positive Discharge Bucket Elevator

The positive discharge bucket elevator is a type of centrifugal bucket elevator. Positive discharge elevators are used for materials that tend to stick to buckets, which prevents the material from being discharged by a centrifugal bucket elevator. These elevators rotate slowly, approx. 2.3 ft (0.7 m) per second, but compensate by having large buckets. Positive discharge elevators are able to dislodge stuck material by passing over an extra sprocket after the head pulley, which provides a jolt. Some may also have a rapping mechanism.^[11]

[edit] Internal Discharge Bucket Elevator

The internal discharge bucket elevator is a type of continuous bucket elevator. The difference being an internal discharge elevator is designed to discharge material along the buckets' internal path.^[12]

[edit] Common Manufacturers

• 4B Components
• BHL Conveyor Technology
• Caterpillar
• Conveyor Industries
• Feeco
• Gerber
• Gouh Econ, Inc.
• GSI Grain Systems
• Internovi\
• Jansen & Heuning
• Lambton
• Link-Belt
• Orthman Conveying Systems
• Ryson
• Schenck Process
• Tapco
  
• Tramco
• Unitrak

[edit] References

1. ↑ Vertical Elevation. Olds Elevator [September 23, 2009].
2. ↑ Bucket Elevators. Orthman Conveying Systems [September 23, 2009].
3. ↑ What Is a Bucket Elevator?. WiseGeek.com [September 25, 2009].
4. ↑ Vertical Elevation. Olds Elevator [September 23, 2009].
5. ↑ What Is a Bucket Elevator?. WiseGeek.com [September 25, 2009].
6. ↑ What Is a Bucket Elevator?. WiseGeek.com [September 25, 2009].
7. ↑ Bucket Elevators. Orthman Conveying Systems [September 23, 2009].
8. ↑ C. R. Woodcock and J.S. Mason. Bulk Solids Handling: An Introduction to the Practice and Technology. Blackie Academic & Professional: 1995.
9. ↑ Bucket Elevators. Orthman Conveying Systems [September 23, 2009].
10. ↑ C. R. Woodcock and J.S. Mason. Bulk Solids Handling: An Introduction to the Practice and Technology. Blackie Academic & Professional: 1995.
11. ↑ C. R. Woodcock and J.S. Mason. Bulk Solids Handling: An Introduction to the Practice and Technology. Blackie Academic & Professional: 1995.
12. ↑ internal-discharge bucket elevator. Hacettepe University Department of Mining Engineering [September 25, 2009].