Category Archives: Bucket Elevator

Industrial Bucket Elevators | Vertical Bucket Conveyors | Bucket Elevator Types

Types of bucket elevators:

Bucket elevators are classified into three types. They classified according to the bucket spacing and mode of discharge. They are:

1. Centrifugal Discharge elevators

2. Continuous Discharge elevators

3. Positive Discharge Elevators

01-layout-of-a-bucket-elevator

Centrifugal Discharge Elevators:

In a centrifugal discharge elevator, buckets are fixed on to belt or chain at regular pitch to avoid interference in loading and discharge. This type of elevators is mostly vertical in operation and can handle practically any free flowing fine or small lumpy materials. The material is fed into the boot of the elevator and scooped up by the buckets as they pass round the bottom pulley or sprocket. The material is discharged by centrifugal force as the buckets pass over the head or sprocket.

These elevators operate at higher speeds than other types. Speed range is 70 to 125 m/min.

In a centrifugal elevator buckets are loaded by the scooping of the buckets at the boot. Hence such elevators are used for relatively fine free flowing materials. Otherwise the buckets will be damaged frequently. Usually lump size larger than 50mm are not used for these types of elevators. On the other hand, it is also necessary to check that the materials are not finer than 200 mesh size. (Materials finer than 200 mesh are often aerated and cause wastage and jamming problems.

Applications:

1. Grain,

2. Coal,

3. Sand,

4. Clay,

5. Sugar and

6. Dry Chemicals.

01-types of bucket elevator - centrifugal discharge bucket elevator - continuous discharge bucket elevator

Continuous Discharge Elevator:

In a continuous discharge elevator, buckets are mounted without any gap on a chain or belt. This type of elevator often used for handling larger lumps of material that may be difficult to convey by centrifugal type. The buckets used with this type of elevator are given such a shape that the belt or chain passes over the head wheel, the flanged end of the preceding bucket acts as a chute to lead the material to the discharge spout. These elevators operate at a speed range of 30 to 50 m/min, which is much slower than that of the centrifugal discharge type. Continuous discharge elevators are not fed by the scooping action of the buckets through the heap of material. A loading leg effects, feeding of material. The slow speed and gentle method of loading and discharging makes this type of elevator suitable for fragile, fluffy or pulverised materials. It can operate in the vertical or inclined condition.

Application:

1. Lime,

2. Cement and

3. Dry chemicals

01-continuous discharge bucket elevator

Positive Discharge Elevators:

This type of elevators is similar to the centrifugal discharge elevator except for two distinguishing features. The buckets are spaced at regular pitch and mounted on two strands of chains, and are provided with a snub wheel under the head sprockets to ensure inverting of the bucket for complete discharge. The speed of the bucket is slow in the range of 35 – 40 m/min.

This type of elevators is used for handling light, fluffy, dusty and sticky materials. The feeding is done by the scooping or digging by the buckets.

01-positive discharge bucket elevator - types of bucket elevator

Bucket Elevator Part | Bucket Elevator Guide | Bucket Elevator How It Works

A bucket elevator is a conveyor for carrying bulk materials in a vertical or inclined path. Bucket elevators for the mechanical, vertical transportation of materials have become a crucial link in the production process in many industrial sectors.

01-bucket elevator for grain- centrifugal type bucket elevator

Typical elevator consists of:

1. An endless belt,

2. A chain or chains, to which buckets are attached,

3. Necessary loading and discharging terminal machinery,

4. A drive arrangement,

5. Supporting frame or casing.

01-layout of a bucket elevator - bucket elevator parts

Material is fed into an inlet hopper. Buckets (or cups) dig into the material, and convey it up to and over the head sprocket/pulley, then throwing the material out the discharge throat. The emptied buckets then continue back down to the boot to continue the cycle.

Industrial Bucket Elevators are made in a variety of shapes, weights and sizes, utilizing centrifugal buckets or continuous buckets. The belt can be made of natural fibres, rubber, plastic or metal.

Centrifugal Bucket Elevators are most commonly used to convey free flowing materials. They operate at high speeds, which throw the materials out the buckets into discharge throat by centrifugal force.

Continuous Bucket Elevators have buckets spaced continuously and operate at slower speeds. The continuous bucket placement allows the force of gravity to discharge their load onto the inverted front of the preceding bucket. The bucket then guides that material into the discharge throat on the descending side of the elevator. They minimize product damage or are used to handle light, fluffy materials where aeration of the product must be avoided.

01-bucket elevator belt and chain type - bucket elevator chain

The motion of belt or chain is un-directional. Bucket elevator is a very simple yet reliable device for lifting of bulk materials. Bucket elevators enjoy a few advantages, which include simplicity of design and fabrication, requires minimum floor space, low initial investment.

Types of bucket elevators:

Often bucket elevators are classified according to the bucket spacing and mode of discharge. They are:

1. Centrifugal discharge elevators

2. Gravity or Continuous discharge elevators

3. Positive discharge elevators

Components of bucket elevators:

The essential components of a bucket elevator are:

1. Buckets

2. Carrying medium

3. Boot arrangement

4. Head arrangement

5. Casings

01-bucket elevator- bucket elevator components - bucket elevator round link chain

Application:

Typical average materials which can be conveyed by bucket elevators are:

· Lime stone crushed to 25 to 30 mm size,

· Foundry sand,

· Coal,

· Coke,

· Sugar

· Animal feed

· Chemicals

· Phosphate rock,

· Cement mill clinker

· Friable

· Fragile materials

· Candy

· Snacks

· Coffee

· Rice

· Seed

· Soaps

· Detergents

· Plastic Granules

Limitations:

Limitations of the system include the following points:

· Lump size should be under 100mm

· The material should not be very sticky

· The temperature of the materials should be ambient or slightly above

· The materials should not be excessively corrosive or abrasive

Advantages of belt system over chain system:

The traction element may be either endless belt or endless chain, but belt system is preferred under certain conditions for the following reasons:

· Higher speeds possible

· Quieter operation

· Possess better abrasive resistance to materials like sand, coke etc.