Material Handling and Equipment's

1. CHAIN CONVEYORS
Prepared By: Yitagesu Tesfaye
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2. INTRODUCTION
 A well-designed chain conveyor made up of high-quality material is
an excellent means of conveying abrasive and high temperature
materials, or withstanding the effects of impact when handling large
lumps.
Chain conveyors employ single or double strands of continuous
wrapped around head and tail end sprockets.
The units are generally operated by motor drives attached to the
head/drive shaft.
Material can be carried directly on aprons or pans or pushed in a
trough by flights attached to the chain(s).
The chain conveyor derives its name from the type of attachment,
is, apron, pan, or flight.
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There are four types of chain conveyors based on whether
the chain slides or rolls and whether the material is pushed
or carried.
Units can be arranged for operation horizontally, inclined,
or vertical.
Lubrication of chains should be carried out per
manufacturer’s recommendations contingent upon usage.
Lubrication of roller chain when handling certain types of
abrasive dusty material may not be advisable.
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4. Apron Conveyors
Apron conveyors are used extensively in particular all modern
mining, manufacturing and processing industries.
They are particularly suited to the handling of incoming raw
materials in process materials and finished materials.
These conveyors consist of a series of jointed overlapping or
interlocking apron pans on which the material is carried.
They can handle abrasive materials that cannot be scraped along a
trough, and as the loading is readily controlled it may be used as a
feeder.
 As an alternative to a rubber belt it can handle materials at a
temperature higher than 1500 𝑐that cannot be handled with rubber.
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7. Aprons and Pans
Aprons and pans are made in various types
selection of the types are made of formed steel, with front and rear edges beaded so that
one overlaps the next to form a continuous surface or trough.
Apron pans can be flat or equipped with side plates to increase capacity and reduce
spillage.
Some of the most commonly used ones are described below
Style A
Aprons and pans are used for horizontal and low incline (200 − 250) services.
Both types in short pitches are used for feeders; pans in medium or long pitches, for
conveyors.
This style is suitable for most bulk materials, including hot dusty, abrasive materials as
shakeout sand in foundries, limestone in cement mills and ores in mining.
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9. Style B
The pans are designed to provide force and easy discharge and
low drop of material. This style is especially suited to handle lump material
which should not be broken.
It is also suitable for wide conveyors and can be used for inclined conveying
up to 300
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10. Style C
The pans are used for large capacities of fines and lumps and inclines up
300
They require a higher discharge point than style B. They are suitable for
as feeding, picking, sorting and lowering conveyors.
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11. Style D
The pans are similar to style B. Built of angles and plates, they are of very
strong and
rigid construction.
These pans are capable of carrying large quantities of material such as coal,
rock and castings.
The pans have complete discharge with very little drop and breakage of
lumps. They have good impact resistance under loading point.
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12. Style E
The pans are super-capacity pans for handling, fine, crushed, or lump
materials in very large quantities.
They can be used for horizontal conveying or inclined conveying as steep as
450
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13. Design consideration for Apron Conveyor
The thickness of the apron pan is dependent upon the weight to be supported on each
apron, impact of the filling lump, and abrasiveness or corrosiveness of the material. Table 9.1 is
a general guide to apron pan selection.
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14. The maximum traction force is a combination of the force required to move the material, the
moving part of the conveyor and the force required to overcome the level difference.
1. The force required to move the materials
𝑓1 = 𝑓𝑔 ∗ 𝑞 𝑚∗ 𝑙 𝑚
𝑤ℎ𝑒𝑟𝑒𝑓𝑔 = 𝑓𝑟𝑖𝑐𝑡𝑖𝑜𝑛 𝑐𝑜𝑓𝑓𝑖𝑐𝑒𝑛𝑡
𝑞 𝑚 = 𝑤𝑒𝑖𝑔ℎ𝑡 𝑜𝑓 𝑡ℎ𝑒 𝑚𝑎𝑡𝑒𝑟𝑖𝑎𝑙 𝑝𝑒𝑟 𝑢𝑛𝑖𝑡 𝑙𝑒𝑛𝑔ℎ 𝐾𝑔
𝑚
𝑙 𝑚 = 𝑡ℎ𝑒 ℎ𝑜𝑟𝑖𝑧𝑜𝑛𝑡𝑎𝑙 𝑑𝑖𝑠𝑡𝑎𝑛𝑐𝑒 𝑡ℎ𝑎𝑡 𝑡ℎ𝑒 𝑚𝑎𝑡𝑒𝑟𝑖𝑎𝑙 𝑖𝑠 𝑐𝑜𝑛𝑣𝑒𝑦𝑒𝑑 (𝑚)
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15. 2. The force required to move the moving parts of the conveyor.
𝑓2 = 𝑓𝑔 ∗ 𝑞 𝑠∗ 𝑙 𝑠
𝑤ℎ𝑒𝑟𝑒𝑓𝑔 = 𝑓𝑟𝑖𝑐𝑡𝑖𝑜𝑛 𝑐𝑜𝑓𝑓𝑖𝑐𝑒𝑛𝑡
𝑞 𝑠 = 𝑤𝑒𝑖𝑔ℎ𝑡 𝑜𝑓 𝑡ℎ𝑒 𝑚𝑜𝑣𝑖𝑛𝑔 𝑝𝑎𝑟𝑡 𝑜𝑓 𝑡ℎ𝑒 𝑐𝑜𝑛𝑣𝑒𝑦𝑜𝑟𝑠 𝐾𝑔
𝑚
𝑙 𝑠 = 𝑡ℎ𝑒 ℎ𝑜𝑟𝑖𝑧𝑜𝑛𝑡𝑎𝑙 𝑑𝑖𝑠𝑡𝑎𝑛𝑐𝑒 𝑡ℎ𝑎𝑡 𝑡ℎ𝑒 𝑐𝑜𝑛𝑣𝑒𝑦𝑜𝑟 𝑖𝑠 𝑚𝑜𝑣𝑖𝑛𝑔 (𝑚)
3. The force required to over come the level difference.
𝑓3 = ± ∗ 𝑞 𝑚∗ 𝐻
𝑤ℎ𝑒𝑟𝑒 𝐻 = 𝑡ℎ𝑒 𝑙𝑒𝑣𝑒𝑙 𝑑𝑖𝑓𝑓𝑒𝑟𝑒𝑛𝑐𝑒
4. The force required to overcome the friction between the chain and the driving gear can
be calculated by:
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16. 5. After calculating the maximum force required, maximum tension, 𝑻 can be used to find the
stress on the shaft. The traction force 𝑹 is equal to the maximum tension 𝑻. This is due to the
fact that the slack side tension is negligible compared to that of the slack side tension of the
conveyor.
6. The power absorbed 𝑲𝑾 :
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17. 7. The more commonly used chain for apron conveyor applications is a steel, bushed roller chain
with pans, bolted to the chain by attachments (Figure below). For non-abrasive materials
weighing 800kg/m3 or less, with a minimum lump size a 100mm-pitch chain is adequate. For
most other materials a150mm pitch and larger chain is used. Manufacturer’s literature should be
referred to for specific application information.
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18. Flight and Wide Chain Drag Conveyors
• A flight conveyor consists of one or more endless propelling mediums, such
as chain or other linkage, to which properly spaced scrapers or flights for
moving material along the length of a stationary trough. Material fed into this
trough is thereby pushed along its length for discharge at the end of the
trough or through intermediate discharge gates.
• Flight conveyors are used for either horizontal or inclined paths and are
frequently installed where the angle of inclination is comparatively steep.
• Flight conveyors may be several hundred meters in length, but as the material
is scraped along a trough they are not suited to abrasives like ashes or sand.
• A modified type called the drag chain conveyor is specifically adopted for
ashes, coal, sawdust, pulpwood and hot or cold cement cylinders.
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19. Construction
• single strand scrapper flight conveyer, in which the flights are
drawn along the trough bottom.
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20. Single strand suspended flight conveyor with wearing shoes
attached to the flights to carry them clear of the trough along the
carrying run and support them along the return run.
Single Strand Flight Conveyor with roller-suspended Flights :is
similar to the suspended flight conveyor except that rollers are
substituted for shoes the roller flight conveyer.
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21. • Double strand flight conveyor with Roller suspended flights:
double strand conveyor with roller chain to carry the flights the
roller chain suspended flight conveyor.
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22. Flight Conveyor Design Consideration
The following factors are essential in the design of a flight
conveyor:
Type of material and its characteristics
Capacity (maximum in tons per hour)
Maximum size of lumps and percentage of maximum lump in
total volume
Length and incline of unit
Service requirements
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23. Sliding chain conveyors are simpler, with fewer moving parts than a roller
chain type but horsepower requirements are higher.
A roller chain unit operates with less pulsation than a sliding chain unit. The
lower friction of the roller chain units permits design of longer units, with
lower horsepower and reduced operating costs, but may be susceptible to
jam-ups.
Flights, normally manufactured from steel, have been made of wood,
malleable iron and other materials spaced at distances from 300mm to
915mm.
Flight spacing is varied to suit the size of lumps, required capacity and slope
of unit.
Table 9.3 is a brief resume of sizes and capacity of available units and
additional data can be found in the manufacturer’s catalogue.
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25. Flight conveyor power required consists of three factors, which are the
following
I. The power required to run empty conveyor
II. The power require to carry load over horizontal distance
III. The power required to lift load
This third component for lift can be disregarded in figuring a horizontal
conveyor. These values can be expressed by the formula:
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30. Special versions of chain/flight
conveyor
One version utilizes chain and specially formed flight which travels through an
enclosed, modified trough. Special head/drive and tail/take-up terminals are
required. The advantages of these units are:
 Standardized parts are readily available.
 They are self-cleaning
 They are gentle handling.
 There are still other modifications of the chain/flight conveyor that
utilize various combinations of chain and bar-type flights for
conveying materials in enclosed troughs. These units are usually
proprietary design of a given manufacturer.

32. Examples

37. Thank You!!
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