Bucket Elevator

About Bucket Elevator

A bucket elevator lifts bulk material vertically in buckets fixed to a belt or chain running inside an enclosed casing. Where a belt conveyor would need a long, gently sloping run to gain height, a bucket elevator does it in the footprint of the casing — which is why it is the usual way to lift fuel from ground level into an overhead boiler bunker or silo.

Two discharge methods cover most duties. A centrifugal-discharge elevator runs faster and throws material out of the buckets at the head as they turn over the pulley; it suits free-flowing fuel such as crushed coal and husk. A continuous-discharge elevator runs slower with closely spaced buckets, so each bucket's load slides onto the back of the one ahead; it suits light, fluffy or fragile material that a fast elevator would throw back down the casing.

Biomass needs particular care. Its low bulk density means a biomass elevator must be sized on volume, with larger or more closely spaced buckets, and wet, sticky fuel can hang up in the buckets and the boot. The design of the inlet, the boot and the discharge chute decides whether an elevator runs clean or chokes.

We design and fabricate belt and chain bucket elevators for boiler fuel and ash, with inspection doors, anti-runback protection and access platforms included rather than added later.

Capacity is a matter of volume rather than weight: bucket size, bucket spacing and belt or chain speed set how much material passes the head each minute, and the fill factor — how full a bucket actually runs — depends on how the fuel behaves at the boot. A dense, free-flowing material fills buckets readily; light biomass does not, and an elevator sized on tonnage alone will be short of capacity the day it is commissioned.

The boot is where most elevators are won or lost. Fuel should be fed into the up-going side so the buckets scoop cleanly; fed into the down-going side, the buckets dig through the accumulated load and both power and wear rise sharply. Wet, sticky fuel that will not leave the bucket at the head comes back down and builds in the boot, which is why the boot is given a clean-out door, a properly sized inlet and, where the fuel warrants it, a shape that will not hold material.

Because a bucket elevator is a loaded vertical lift, its protection matters more than on a horizontal conveyor. A holdback stops the loaded leg running backwards when power fails; belt slip, misalignment and zero-speed sensing stop it before a slipping belt polishes the pulley or a misaligned belt cuts into the casing. Where fine, dry dust is being lifted, the casing is treated as a dust-handling enclosure, with attention to ignition sources and to venting.

Typical duty is lifting husk or crushed coal into an overhead bunker in a rice mill or process boiler house, filling a day bin above a feeder, and elevating fly ash into a storage silo. We supply bucket elevators as part of a complete fuel handling chain with conveyors, screens and bunkers, or as a single replacement unit into an existing casing line — with erection, commissioning, spares and an AMC where the plant wants one.

Bucket Elevator Key Features

• Enclosed casing for dust-free vertical lifting
• Belt or chain elevator selected for the material
• Centrifugal or continuous discharge to suit the fuel
• Buckets sized on volume for light biomass
• Boot designed to limit hang-up of wet fuel
• Anti-runback holdback and zero-speed protection
• Inspection doors and access platforms
• Small footprint for lifting into bunkers and silos
• Capacity set on bucket volume and fill factor, not tonnage alone
• Inlet arranged so buckets load on the up-going side
• Boot with clean-out door and no material-holding corners
• Belt slip, misalignment and zero-speed protection
• Screw or gravity take-up to hold belt or chain tension
• Bolted head and boot sections for erection in a tight boiler house
• Dust-tight casing joints throughout the lift

Bucket Elevator Specification

Materials Handled

Bucket Elevator Types

Bucket Elevator Applications

Industries Served

Advantages of a Bucket Elevator

Optional Accessories