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.
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.
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.
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
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.
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