Types of material handling equipment’s

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elevator

- Bucket elevator (or elevating conveyors)

are used for transporting dry granular materials in the vertical direction with help of buckets and trays.

- There also known as bucket elevating conveyors and carry the material in bucket to vertical or near vertical positions.

- There are (i) either chain bucket elevator in which buckets are attached to one or two chains which move one two end wheels or (ii) belt bucket elevators in which buckets are attached to the belt moving on pulleys provided at two ends. 

- Bucket elevator are operated between head and foot terminal machinery in a supporting frame. The bucket are loaded by scope action at foot end or by a chute above.

- Belt type have higher speed and capacity smoother and quieter which chain types are heavier duty and suitable for abrasive material bucket elevators are sometime used as portable elevators which are known as stackers consists of a base on wheels a vertical frame a lifting or lowering mechanism and a load carrying platform.

- Lifting of such elevators is accomplished by hydraulic or mechanical action.

- Bucket elevator are consists of an endless chain of buckets which bucket elevators the material. Theel evator is usually enclosed in a sheet of metal casing with necessary inlet and out let openings and chutes. They are widely used in handling cools chemicals cement etc.

- Bucket elevators consist of a line of pivoted buckets end mounted between two strands of rivet less chains so that the center of gravity is below the pivot in every bucket.

- As a results buckets travel in stable equilibrium and automatically drop back into the horizontal position after being discharge by tilling.

- Normal operating speeds of those conveyors is between 0.15 and 0. 40 m/sec. these conveyors are available up to 400 tons/ltr.

- Normal lifts of those range up to 30 meters but in special cases may range up to 100 meters.

- For unloading tripping arrangement are used in the form of fixed or moveable devices. On being overturned as the point of discharge buckets become back into the original position.

- In a bucket conveyors freely swinging (pivoted) buckets are carried between a parallel endless chains which follow any path vertical horizontal or inclined.

- The bucket are loaded by a specially designed feeder and are unloaded when they are tripped or inverted at set point these are rugged slow running and capable of providing trouble free service. 

- Screw conveyors also known as spiral conveyors consist of a screw rotating in a stationary through or tube. As the shaft on which screw type spiral blade causes the material to be pushed forward along the through.

- Screw conveyors can be operated in a horizontal inclined or even vertical upward direction while the materials are being moved the screw conveyors can also be used to perform the process of blinding and mining of materials.

- These are used to move materials over a through by rotating screw. This is formed by a helical blade attached to a drive shaft which is coupled to a drive and supported by end bearings and by inner bearings.

- The through of the round bottom shape is topped by a cover plate with an opening for loading the conveyor.

- A similar unloading opening is provided in the bottom of the through. The helical blade forcing the load along the through when the shaft is set rotating is made of 4- 8 mm steel plate and attached to the shaft by welding.

- Helical spiral blade are used for dry materials ranging in size from powder to lumps ribbon spiral blades are used to handle coarsely broken and sticky loads. Paddle spiral and cut flights are adopted to convey flow resistant solids tending to cake.

- Screw conveyors are widely used to handle dusty or hot loads liberating harmful gases these are also used for handling powders foods products pulverized coal (for feeding into the furnace) or other granular materials.

- Screw conveyors can also operate vertically lifting material up to 150 m. screw feeder or a horizontal screw conveyors which serve to create a thrust at the food of the lifting 

Vibratory conveyors

- In vibrating conveyor vibrations are created at high frequency and small amplitude. The vibration are induced electrically or mechanically.

- These conveyors are rugged require low maintenance.

- These conveyors are generally used as a feeder and for screening blending or separating.

- These conveyors are fitted with metal or plastic through over which materials consisting of fragments of varying size are kept which while moving are separated at a high speed.

- For designing a vibratory conveyor it is essential to specially nature of material to be handled indicating density grain size and other characteristics. 

Feeders and screw

- During processing in any industry it is essential for effective and efficient performance to have uniformly controlled feed.

- Uniform feeding operation and its control is obtained either by mechanical or electrical means.

Mechanical feeders are generally of 3 types:-

1. Adjustable feed opening.

2. Adjustable speed

3. Vibratory.

- In order to control the feeding rate or to achieve the varying feeding requirements mechanical feeders ( generally hoppers) are equipped with provision of adjusting the gates at feed opening or variable speeds drives.

- Selection of the type and size of the feeder depends upon capacity requirement material characteristics and size flow ability moisture contents etc. commonly used feeding

 arrangements are:-

1. Belt feeders

These are the short belts and feeds the material

at a uniform rates. These are provided at the

 bottom of the hopper and extracts the material

from it. For varying the rate of discharge the

 speed of feed belt is varied as per requirement.

2. Hoppers with adjustable gates and

chutes

- These are used for feeding the material to the belt conveyors. These are used for uniform loading the running belt through a chute and the rate of material flow is controlled through the gates at the month of the chutes.

- These gates can be controlled either manually or hydraulically or electrically or by means of compressed air chute is used to discharge the material on the conveyor belt in its direction of movement so as to reduce the impact of material on belt.

- The size of the chute opening should be designed in such a way so as to avoid blockage of opening by lumpy materials if any. The inner walls of the chute should be lined with the anti-a brasive material.

- To avoid the spillage of material and guide. The material or belt two rubber pads are also provided on the sides at the loading point.

3. Vibrating feeders

- When loading non free flow material vibrating feeder are used. Vibrations are produced by electromagnet means are mechanical means. This feeding system is most suitable for all types of bulk materials may it be dry or damp hot or cold fume or coarse size grains.

- The vibrating mechanism is fitted either on wall of the hopper above the chute or in case of rectangular container the device is fitted at the bottom plate to produce vibrations. 

Drag chains & cable  ways 

Drag chains 

- These are  used by chains or cables in horizontal  direction and  installed flush with  floor or a little above it. 

- This is used for  moving barrels and heavy boxes. This  is also used for  moving grates of big boilers and  serve as a  continuous  moving table. Chain conveyors  employ  continuous 

chains wrapped  around head and tail  end sprockets.

- The conveyors  units are  generally operated  by motor drives  attached to  the head  drive 

shaft. Material  can be carried  directly on a  prone or  pushed in a trough  by flights  attached to the chain.

- The chain conveyors  may be apron flight bucket  car conveyors  depending upon the  type of attachment uses. The  units can  arranged for operation horizontally  inclined or in combination  these  can be designed to  operate  up to 45⁰ inclination.

- Capacity of  a chain conveyor is  equal to. Available  cross sectional  area ᵡ chain speed. 

Speed of the chain  depend upon the  type of  material and varies from 3-6 m/min for 

abrasive  material to  about 30 m/min or  more for  mild abrasive  material. 

- Chain conveyors  can be used at  elevated temps can  handle coarse  broken  material un-

 suitable for belt temps. Chain  positively transmit the  drive imported to it  by the sprocket and displays low stretch  ability nuclear a low. 

Cable  ways 

- Cable  way is a  single span overhead conveying system. In cable  way  while traversing load can be raised or  lowered at any point. This  is very  useful in excavation work in dams  work pits quarries etc.  where load are hoisted and moved horizontally. 

- These  are also used for transporting  and then  placing the concrete in concrete structure. A cable  ways is supported on  live  end  supports and  consists of the  track cable the carriage the traction rope and the heist rope as  shown in fig. 

- One  support heaving and  operating  gear is  known as head tower  while  the other is known as tail time. 

- A  track cable ( strong  steel cable) is stretched over  these  two and towers. The carriage is 

 attached to an  endless traction drown  under  the head tower. 

- The hoist rope is supported  between carriage and  the head tower  on the  carries hanging 

from the traction rope. The cable  ways are  generally operated at speeds  between 150-400 

m/min  during  level and  between 30- 100 m/min  during lifting and lowering. It  usually  carry a carriage load  between 3-10 tons. 

Bulk Bins hoppers Big Bags 

And utilized bulk operations A system of vertical and horizontal pipe having intake hoppers receiver filters dust filters bulk bins

with blowers and motors which carry particle of solid material by means of air pressure in the material handling system is called pneumatic conveyors. 

These are classified as:- 

1. positive pressure 

system In this system a blow creates the positive air flow in the pipe line and materials are injected into the air stream and below via the pre-set conveying path. 

2. Negative pressure (vacuum) system 

In this system vacuum is created in the pipe line. A suitable intake mechanism with a hopper and a receiving station is provided where material particles are separated from the moving air stream by tangential or cyclonic action and discharged to storage or process bins. 

3. Combination system 

- This employ both the positive and negative systems. In this systems vacuum is used for unloading of material from storage there after 

positive pressure is used for distributing into single or multiple storage bin. 

- Pneumatic conveyor are used for transporting dry granular material chemical ponder sand and cement etc. this system is cleaner dust free easy to install requires lesser staff to handle or operate and minimum interruption.

- Maintenance is also less since moving part are not involved. This system is popular for

handling cement on large scale construction work. The initial cost of this system is related

high and the use is limited to selected mate

- This type of conveyor system is economical because of the

i. Saving in the cost of bags & other packages.

ii. (Lass expenses on bulk handling)

iii. Less labor costs

iv. No chances of damages spillage or residual materials in the discarded bags.

- This factors determining the power requirements and the size of the equipment’s

are:-

i. The vertical lift.

ii. Horizontal pipe length.

iii. Size of material to be transported.

iv. Through put required.

A pneumatic conveying system consists of:-

1. Air supply unit

It is generally consist of blower gear box and a motor.

2. Feeder unit

It is used to transfer the material into pipeline. These should be able to with stand the abrasion

of the material to be transported.

3. Pipe lines

It should be storage enough to suit the properties of the conveyed material and the pressure of system.

4. Separation unit

It is usually employed for reporting the material at destination. These are high efficiency cyclone separators. 

Vehicle bulk handling system

Marine bulk material handling

- Cranes have wide application in bulk material handling system such as vehicles. Marine

construction projects industries and shipping etc.

- These are also used for lifting the load (may be construction materials, loose material

packages, Finished & semi-finished products in industries, containers etc.) and placing

them at desired place.

- For this purpose cranes have three motion in general namely: hoisting, derricking and

slewing these cranes are generally electrically operated. Diesel operated or may have diesel electric drive.

The cranes can be classified in following classes:-

1. Derrick cranes

- It consist of a mast, a boom, a bull wheel on

which it rotates about a vertical axis and

supporting members (known as gays).

- These cranes are very widely used in construction projects loading and unloading

cargo at ports, ship building, marine handling and vehicle handling plant erecting etc.

- These cranes can be used as tower cranes for the purpose of erecting of high industrial and

residential of height 100 m or above.

- The derrick cranes can also be designed to work as port lower cranes for containers heavy

vehicles, marines and general cargo handling. These are also be used as shipyard cranes

for ship building and ship repairing work with higher capacities and longer working radii.

- The derrick cranes are sometime mounted on rail wagons for quick transportation and for

working near rail lines. These cranes are available up to 40 tons with 25 m boom length and 15 ton on work radii .

 2 Mobile cranes

- Mobile cranes are either

• Crawler mounted

• Wheel mounted

- Crawlers mounted cranes are highly

maneuverable and have the ability to operate

on unmade ground of poor condition

- These move slowly and operate in a limited

area.

- Wheel mounted mobile cranes are generally truck mounted, have mobility, can travel up to

70-75 km/hr. good roods.

- These are designed for long distance travel with high rood speeds.

- The number of axles and drives depends upon load lifting capacity and the length of the

boom. These cranes can operate on firm ground. For increasing base width and to improve

stability during operation outriggers are used.

The mobile cranes have four motions:- 

i. Hoisting 

ii. Derricking 

iii. Slewing 

iv. Traveling 

- Rail mounted cranes are also manufactured to move on rail tracks. Such cranes are used in 

steel industry dockyard, railways. These cranes can be driven by diesel engines are by electricity. These are design suit the railway gauge clearance available to lift high loads such as required for salvage operation after accident etc.

. Hydraulic Cranes 

- Hydraulic cranes are usually truck mounted crane all operations of these cranes are 

hydraulically power including extension and reduction of outriggers extension and 

shortening of boom. 

- The hydraulic power is supplied through oil pressure generators by rotary oil pumps. 

Because of simplicity quick chain of boom length, easy and quick change of angle mobility 

and manor operability of the telescopic boom no requirement of a separate crew for 

extending are shorting of the boom. 

- The cranes have attained the wide popularity over conventional cable operator latticed 

boom. 

- Besides the operation of hoisting, slewing and derricking can be performed simultaneously 

and without any jerks which are unavoidable in conventional cranes. 

- These cranes mostly used in dockyards ware house sliding etc. for lifting and lowering 

heavy loads up to 250 tons. 

- Its main advantages over electric cranes is that these can be adopted to suit varying conditions. 

- Hydraulic cranes consists of two main parts 

1. Jigger 

2. Craning arrangement 

1. Hydraulic jigger 

- It is an arrangement of pulleys for increase the velocity ratio. It consists of a fixed cylinder in 

which a ram moves. A number of pulleys (2 to 6 fitted by sides by side) are fixed on the top 

of a ram and similar numbers is fixed at the end of the cylinder.

- A wire rope with one ends fixed at point on the cylinder is taken round all the pulleys on ram and cylinder alternately and finally to the other end is taken round a pulley fixed at the top of the mast (hollow vertical post) of the craning arrangement.

- It is then taken down after passing through a pulley fixed at the junction of jib and tie rods. 

At the free end a hook is provided for hang load. Jigger may be kept either horizontally or 

vertically.

2. Craning arrangement 

- The crane consist of a hollow vertical mast to which job and a tie rod is attached as 

showing in fig. 

- The mast is supported on bearing and can be revolved with its vertical axis so that load 

from a direction can be handled. The jib can be raised or lowered together with the load.

Overhead and Gantry Cranes 

- There are used for handling load over a long rectangular area in factories power station in 

shipyards and in workshops. 

- The simplest from manually consists of:- 

i) Structural bridged support of elevated tracks. 

ii) Supporting a lifting block or hoist trolley. 

- Control is made from a cabin on the bridged or from flow level. Due to freedom from flow 

abstractions these are widely used in erection foundries, steel plant, power houses and 

shipyard etc. 

- The bridged consist of two main girders which are fixed at the end and supported on train 

wheels and can move on gantry rails the hoist trolley (crab) is supported on these girders. 

- Thus load hook has three motions:- 

a) Hoisting lifting and lowering. 

b) Cross travelling with trolley in both directions. 

c) Longitudinal traversing with bridge in both directions. 

Traveler cranes 

- These cranes have their crabs (hoisting 

trolley) moving on girders which are 

supported on legs instead of overhead 

/gentry cranes. 

- The legs moves on tracks laid on the flow. 

Since these do not need overhead gantries hence are very useful as dock site cranes for 

lifting cargoes in shipyards and in docks etc.

Tower cranes

- Tower cranes are used in various construction projects of high buildings bridges, cooling towers, television towers, power plants and shipyards building etc.

- It can work and then dismantled as required

the lower has a truss structure welded from

angle bars and channels.

- Tower extension pieces are available to

increase the height as per requirements.

Ladders are provided inside the whole heights of the tower. An operation cabin is provided

and as to enable full view.

- Jib is attached to the last highest section of the lower. Two section of the jib opposite to one

another are provided one is saddle jib and another is counter weigh jib.

- A saddle move horizontally on rails provided on the saddle jib and is controlled from the

hook block. The upper portion of the tower is fixed in the slewing head.

Derrick:-

 A simple loading cranes that is typically used from moving cargo into or from ship.

Slew:-

A wet place to turn, swing, twist.

Crew:-

A group of people who work together on a project or task.

A crowd or gang:-

On board staff the people who work on a ship, air craft or space craft.

Riggers:-

To extend part of boat a beam or frame work sticking out from the side of a boat.

Jiggers:-

A device such a drill that operates with a jerking or jolting motion.

Jib:-

To shift from one side to other.