Material Handling systems
Material Handling principles
Classification of Material Handling Equipment
Relationship of material handling to plant layout
3. MATERIAL HANDLING SYSTEMS
“Material handling embraces the basic operations in connection
with the movement of bulk, packaged and individual products in
a semi-solid or solid state by means of gravity manually or
power-actuated equipment and within the limits of individual
producing, fabricating, processing or service establishment”
Materials handling can be also defined as ‘the function dealing
with the preparation, placing and positioning of materials to
facilitate their movement or storage’
4. Material handling does not add any value to the product but adds
to the cost of the product and hence it will cost the customer
more. So the handling should be kept at minimum.
Poor material handling may result in delays leading to idling of
Material handling is the art and science involving the movement,
handling and storage of materials during different stages of
manufacturing. Thus the function includes every consideration of
the product except the actual processing operation.
In many cases, the handling is also included as an integral part of
the process. Through scientific material handling considerable
reduction in the cost as well as in the production cycle time can
14. Common types of Conveyors are:
1. Chutes: It is the simplest device which has both vertical and horizontal
motion. They may be either straight or spiral. These gravity chute
conveyers, large or small, curved or straight, are used to move materials
from higher level to lower level
2. Roller conveyor: Cylindrical rollers which are fitted on the frame, are
used in roller conveyor. They are driven by gravity. Some may be
powered. But they are expensive than gravity roller conveyors. In gravity
conveyors, the driving force is applied directly to loads as these move,
cause rollers to rotate.
3. Wheel conveyor: Operation is similar to that of roller conveyors. The
only difference is the wheels are used instead of cylindrical rollers.
4. Belt conveyor: Used to transport materials for a considerable long
distance. It consists of belt running over drums or pulleys provided at the
end and are supported at intervals by a series of rollers known as idlers.
5. Chain conveyor: Chain is used instead of belt. It consists of one or more
endless chains that can travel the entire conveyor path.
6. Screw conveyor: Also called Auger conveyor. It consists of a screw
rotating in a stationary tube or shaft. As shaft rotates, the spiral
blade(screw) causes the material to move.
18. Overhead crane: Used for handling loads over a rectangular area
in factories, power stations, shipyards and in workshops. The
simplest overhead crane consists of:
(i) Structural bridge support on elevator tracks
(ii) Supporting a lift block or hoist trolley
Control is from cabin on the bridge or by pendant at floor level.
Due to freedom of floor obstruction, these are widely used in
erection, foundries, steel plants etc.
19. Tower crane: Used in various construction projects of high
buildings, bridges, cooling towers, television towers or power
plants. The construction of the tower crane is such that it can
work and then be dismantled in restricted space.
20. Hoists: Hoists are device for lifting or lowering the loads,
suspended from a hook on the end of a retractable chains or cables.
The loads are generally supported from overhead by a hook or
travelling on a track.
Hoists are of different types:
(1) Power hoist
(2) Worm-wheel hoists
Power hoist: It is operated between fixed guide rails, for lifting
things vertically. The simplest is the chain hoist, which is operated
by hand. There are also hoists operated by compressed air, diesel
engine, or by electric power. The hoists are similar to elevators
except that, a hoist does not carry the operator in it.
Hoists are used for short distance horizontal hauls are suspended
from trolleys or carriers travelling over an overhead single rail
track, commonly a rolled I-beam
21. Worm-wheel hoist: This arrangement is employed with two chains.
The one chain is called the hand chain where the other chain is the
load chain. The pull applied to the hand chain is transmitted to the
load chain after being multiplied by the mechanical advantage.
Winch: Winches are used to lift loads vertically by winding the rope
or cable on a drum. These can be operated manually or by power to
get a much greater mechanical advantage than that obtained with the
help of a pulley system.
23. 6. Elevators
Elevators are machines for lifting and lowering loads vertically
with intermittent recuperating motion in :
(i) Multi-floor factories
(iii) Stores and terminals
The common types of elevators are:
(i) Hydraulic elevator
(iii) Cage elevators
(iv) Hydraulic lift
(v) Bucket elevator
25. Hydraulic elevator: They are similar to hoists, but the difference
is operator rides with the load. The speed of the work is enhanced
by using these elevators, and they make supervision easy.
Application: For very high structures like cooling towers, chimneys
and TV towers. These elevators can be made to travel even on
inclined/curved surfaces, can go up to 600 meters.
26. Monorails: Loads are suspended from wheeled carriers or
trollies that are rolled along the overhead track. The carrier wheel
generally rolled along the top surface of the rail forming the
track, where as trollies are supported from or within an overhead
track and connected by an endless propelling medium such as
chain or cable.
27. Cage elevator (Lift): They can be freight or passenger lifts. The
type of drive may be electric/hydraulic. Electrically driven types
are more popular. Travel speed of freight elevator ranges from
0.1m/s while passenger lift travel at a speed of 0.5 to 3 m/s.
Passenger lifts are usually available in capacities of 0.25 to 1.5
tons, freight elevators can handle 0.25 to 15 tons.
28. Hydraulic lift: It consists of a cylinder and a ram. A platform or
a cage is fitted at the top of the ram. Load or persons are carried
from one floor to the another floor by means of these platform or
29. Bucket elevators: They are used for transporting dry granular
materials(materials that will not stick to the buckets) in the
vertical direction with the help of buckets and trays. These are
either (i) chain bucket elevator, in which buckets are attached to
one or two chains which move on two end wheels, or (ii) belt
bucket elevator, in which buckets are attached to the belt moving
on pulleys provided at two ends.