Design and Model of Bucket Elevator

A

Project Report

ON

“DESIGN AND MODEL OF BUCKET ELEVATOR”

Under The Guidance Of

Prof. Y.D. Patel

Assistant Professor, A. D. Patel Institute of Technology

In partial Fulfillment for the award of the degree

Of

Bachelor of Engineering

In

Mechanical Engineering

Prepared By

UTKARSH AMARAVAT

(080010119001)

Submitted to

A.D. Patel Institute of Technology, New V.V. Nagar

May, 2012

i

DECLARATION

I, UTKARSH AMARAVAT hereby declare that the report on entitled “Design and Model of

Bucket Elevator” is a result of my own work and my indebtedness to other work Publications,

if any, have been duly acknowledgment.

Place: - Anand, Gujarat, India

Date: - 6th May, 2012

Utkarsh Amaravat

ii

ACKNOWLEDGEMENT

I deem it a privilege to have been the student of Mechanical Engineering stream in A. D.

Patel Institute of Technology, New V. V. Nagar. My heartfelt thanks to Prof. Y. D. Patel, my

project guide who helped me to bring out this project in good manner with his precious

suggestion and rich experience. I gratefully acknowledge my sincere thanks to my friend

Nirav Sathwara for working as Co-partner and all other friends who help me in this project in

such critical situations and make my project memorable.

I hardly thank to my principle sir Dr. R. K. Jain who grant us permission for economic help

for model making also Mr. Karimbhai, Mr. Samirbhai, Mr. Anandbhai, Mr. Sureshbhai, Mr.

Manishbhai, Mr. Harshadbhai, Mr. Mineshbhai, Mr. Yogeshbhai, Mr. Bharatbhai, Mr.

Birenbhai and Mr. Aashishbhai the staff’s members of ADIT workshop, without help of them

this work is not possible.

iii

ABSTRACT

In this modern competitive industrial world one can get a step ahead of his competitor by

selection of proper material handling equipment. Material handling process is overhead for

the production but it is heart of any process plant. Still people prefer most advanced material

handling equipment even though they are costly. But cost can be justified after prolonged

usage of that equipment.

Bucket elevator has evolved as advanced material handling equipment in mechanized bulk

material handling industry. The effective use of different type of bucket elevators are

completely depends on its design and type of bulk material. In this report different types of

bucket elevator are discussed along their different parts and the design of centrifugal

discharge bucket elevator with simultaneous buckets for lifting wheat at a certain height is

reported for a particular output rate. Detailed design, CAD parts, coding for the design

procedure of bucket elevator, fabrication related data and future scope of work and at last

satisfactory conclusion is worked out in successive chapters.

iv

LIST OF TABLE

Table No.

Table Description Page No.

2.1 Recommendation for selecting bucket elevators 23

2.2 Main characteristics of buckets 26

2.3 Recommendation for selecting bucket Dimension by Maxi-lift 34

3.1 Bill of material for bucket elevator 45

4.1 Design inputs for prototype model 49

4.2 Design outputs for prototype model 49

4.3 Fabrication processes for bucket elevator 51

5.1 Observation table for 10.00 kg of wheat 63

5.2 Observation table for 24.75 kg of wheat 63

v

LIST OF FIGURE

Figure No.

Figure Description Page No.

1.1 Simple belt conveyor 3

1.2 Simple bucket elevator 4

1.3 Parts of simple belt bucket elevator 5

1.4 Belt bucket elevator 6

1.5 Positive discharge bucket elevator 9

1.6 Gravity discharge bucket elevator 10

1.7 Horizontal discharge bucket elevator 11

1.8 Centrifugal discharge bucket elevator 12

1.9 Twin legged discharge bucket elevator 13

1.10 Single and double bucket elevator 14

1.11 High or Super capacity bucket elevator 15

1.12 Bunge Russia – Oilseed bucket elevator 17

1.13 New Zealand - Bins plant bucket elevator 17

1.14 Cimbria (Egypt) - Bins plant bucket elevator 18

1.15 Bahrain-Coke calcining plant bucket elevator 18

1.16 Jordan - Fertilizer plant bucket elevator 19

2.1 Diagram to calculate the pole distance 20

2.2 Forces acting during bucket unloading 21

2.3 Diagram to determine the paths of ejection of material from buckets 21

2.4 Effect of bucket width B on io/tb ratio 25

2.5 Diagram for elevator calculation 28

2.6 Diagram for bucket calculation 34

3.1 Bucket 40

3.2 Ball bearing 40

3.3 Belt 41

3.4 Shaft 42

3.5 Pulley 43

3.6 Bucket elevator assembly 45

vi

3.7 Mechanism of bucket elevator 46

3.8 Mechanism problem-1 of bucket elevator 47

3.9 Mechanism problem-2 of bucket elevator 47

3.10 Mechanism problem in case study 48

4.1 Side part of bucket 53

4.2 Bend part of bucket 53

4.3 Sheet metal planning for all bucket 53

4.4 Loading and bending moment diagram for upper shaft 56

4.5 Fabricated bucket elevator prototype model 58

5.1 Variation based on lifting height 59

5.2 Variation based on pulley diameter 60

5.3 Variation based on capacity 61

5.4 Variation based on efficiency 62

vii

LIST OF SYMBOLS, ABBREVIATIONS AND

NOMENCLATURE

R Resultant

P, F Forces

Rp Pulley radius

hp Pole distance

ra Bucket circle radius

β Bucket angle

Q Capacity

H Lifting height

ρ Wheat density

ν Belt speed

Dp or dp Pulley diameter

N Rotational speed of pulley

B Bucket width

V Volume

Bb Belt width

tb Bucket pitch

Ψ Average coefficient of bucket filling

mrb Linear mass of belt

g Gravitational constant = 9.81

mb Mass of bucket

T Tension

ζ Resistance on take-up pulley

Ksc Scooping resistance

K Safety factor

W Pulley resistance

μ Coefficient of friction

P Power

η Efficiency

Bp Width of pulley

viii

t Pulley rim thickness

L Belt length

C Centre distance

τs Allowable shear stress

w Width of key

h Height of key

rh Hub radius

d Inner diameter of bearing

D Outer diameter of bearing

b Width of bearing, Projection of bucket

Co Static load

C Dynamic load

h1 Depth of bucket

θ Angle of contact

α Angle subtended by each common tangent

п 3.14

ix

TABLE OF CONTENTS

Page No.

Declaration i

Acknowledgement ii

Abstract iii

List of Tables iv

List of Figures v

List of Symbols, Abbreviations and Nomenclature vii

Table of contents

ix

1. Introduction

1.1 Material handling equipments 1

1.2 Bucket elevator 5

1.3 Classification of bucket elevator 8

1.4 Application of bucket elevator 15

1.5 Presently installed bucket elevator in abroad

17

2. Design of bucket Elevator

2.1 Bucket elevator geometry 20

2.2 Design input data for bucket elevator 22

2.3 Flow chart for coding of design

35

3. Modeling of elevator

3.1 Introduction of modeling and its significance 39

3.2 CAD parts of bucket elevator 40

3.3 Assembly of bucket elevator 44

3.4 Bill of material 45

3.5 Mechanism of bucket elevator

45

x

4. Fabrication of prototype

4.1 Selection of prototype dimension 49

4.2 Fabrication of bucket elevator prototype 51

4.3 Selection of power pulley 55

4.4 Bending moment diagram of upper shaft 55

4.5 Problems occurred during fabrication 57

4.6 Fabricated prototype of bucket elevator

58

5. Results analysis

5.1 Effect of operating variables on performance 59

5.2 Result analysis of prototype model

62

6. Scope of further work

64

7. Conclusion

65

Appendix: A

xi

Bibliography xxv

1

Chapter 1: INTRODUCTION

1.1. MATERIAL HANDLING EQUIPMENTS

Expressed in simple language, Material handling equipment is relates to the movement,

storage, control and protection of materials, goods and products throughout the process of

manufacturing, distribution, consumption and disposal. One of the definitions given by the

American Material Handling Society is: “Materials handling is the art and science of moving,

packaging and storing of substance in any form.” To do it safely and economically and

efficiently, different types of tackles, gadgets and equipment are used, when the materials

handling is referred to as mechanical handling of materials.

Material handling also should be considered with in a system context. Rarely, if ever, are

activities performed in a one area or department of a facility without having an impact on

other operations. Example: The efficiency of store room will affect the efficiency with which

the production operations are performed out on the shop floor. The positioning of conveyor

line in plant might improve material flow through the facility or it could present a hindrance

to plant traffic. A significant improvement in the efficiency of one operation, without a

corresponding improvement in a subsequent step in the work sequence, may only result in a

piling up of materials down the line.

These simple examples illustrates the point that to maximize overall productivity of the plant

or warehouse, the material handling steps that supports production, order assembly, and other

operations must be integrated in to a system of activities rather than being viewed as a

number of isolated independent procedure. In addition to considering time and place utility

and system approach, a through definition of material handling must also include the human

aspect. People are always a part of material handling weather the operation is simple one,

involving only a few items of equipment, or a large, complex, automated system.

Maintenance personnel keep the equipment working properly and keep downtime to a

minimum. Foremen and supervisors oversee overall operations, making sure they meet the

objectives of the department or plant. Training in operating procedure, and in safety practice,

is usually required to make handling operation pay off as expected.

2

Finally, the definition of the material handling must contain an economic consideration.

Certainly the delivery of parts and materials to a specific time, it not completely meaningful

unless accomplished at an acceptable cost so that an adequate return is realized. Material

handling is a system or combination of methods, facilities, labour, and equipments for

moving, packaging and storing of materials to meet specific objectives. A materials handling

operation can be simple and small, and involve only few pieces of basic equipments. Or, it

may be large, complex or automated. Material handling equipment is generally separated into

four main categories.

Storage and handling equipment.

Engineered systems.

Industrial trucks.

Bulk material handling.

Bulk material handling is an engineering field that is cantered around the design of equipment

used for the handling of materials such as ores, coal, cereals, wood chips, sand, gravel and

stone in loose bulk form. It can also relate to the handling of mixed wastes. Bulk materials

handling plants and processes quite often require the elevation (lifting) of bulk materials to

other parts of the plant or process. Numerous technologies and equipment are currently

available for this purpose to the designer and practitioner. Generally they are classifying in to

three main categories.

Pneumatic conveyor or air lifter.

Conventional screw conveyor.

Bucket elevator.

Conveyor is almost universal in application. It can travel for miles at speeds up to 5.08 m/s

and handle larger amount of weight in metric tons with the help of belt. It can also operate

over short distances at speeds slow enough for manual picking, with a capacity of only a few

kilograms per hour. Generally they are use in inclined position and not preferable for vertical

transport. However, it is not normally applicable to processing operations, except under

unusual conditions. Belt conveyors inside the plant may have higher initial cost than some

other types of conveyors and, depending on idler design, may or may not require more

maintenance. However, a belt conveyor given good routine maintenance can be expected to

outlast almost any other type of conveyor. Thus, in terms of cost per ton handled, outstanding

3

economy records have been established by belt conveyors. However, these methods of

elevation can experience a range of problems and limitations, such as in case of:

Pneumatic conveying or lifting:

Relatively high operating costs e.g. blower and compressor

Product velocities and wear rates especially for dilute-phase conveying.

Screw conveying:

Relatively high operating speeds due to slippage between the screw flight and

particles and also due to the back-flow of material through the screw flight and

casing clearance,

Increased particle attrition,

Undesirable casing or screw contact.

Figure 1.1: Simple belt conveyor

(Source: www.enviro-abrassion.com)

4

Bucket elevator is a type of vertical or inclined transport equipment that efficiently moves

goods between floors, vessel or other structure. Elevator is generally powered by electrical

motors that either drive traction cables or counterweight system like a hoist or pump

hydraulic fluid to raise a cylindrical piston like jack. Generally it is preferred for short in

distance compared to belt conveyor. It is more preferable to transport the materials vertically.

The detail explanation of bucket elevator is given in next chapter.

Figure 1.2: Simple bucket elevator

(Source: www.swo-conveyors.com)

5

1.2. BUCKET ELEVATOR

Bucket elevators are the simplest and most dependable units for making vertical lifts. They

are available in a wide range of capacities and may operate entirely in the open or be totally

enclosed. The trend is toward highly standardized units, but for special materials and high

capacities it is wise to use specially engineered equipment. Main variations in quality are in

casing thickness, bucket thickness, belt or chain quality, and drive equipment. The main

purposes of bucket elevators are used to lift bulk materials from one height to another. They

are a reliable and well-proven piece of equipment. The various major parts of bucket elevator

are shown in figure.

Figure 1.3: Parts of simple belt bucket elevator

(Source: www.BEUMER.com)

Inspection

panel

Boot

pulley

Relief

vent Bridge tree

Take-up

assembly

Head

pulley Motor

Friction

material

Head

section

Hood

Belt

Casing

Boot

section

Boot Discharge

Bucket Boot

bearing

Short trucking Boot inlet

Adjustable

throat plate

6

The detail description of various parts of bucket elevators is discussed bellow. The major

components of belt bucket elevator are

Drive head

Bottom head

Inlet

Outlet

Buckets

Casing

Drive unit

Take up

Figure 1.4: Belt bucket elevator

(Source: www.motridal.com)

Drive head

Bucket

Inlet

Casing

Take-up

Drive unit

Or Motor

Outlet

7

Drive Head and Bottom Head: Drive head section made with high thickness steel sheets

heavily stiffened. Steel split upper cover easily removable for inspection and maintenance of

drive pulley or wheels. Dust or relief vent on top and inspection panel located at some height

of the outlet. Bottom head is made with high thickness steel sheets is equipped with a

removable bolted door for inspection and cleaning.

Inlet and Outlet: Openings prearranged for the connection with other machines; chutes lined

with wear resistant material when required.

Buckets: On the basis of the conveyed material characteristics the buckets are generally

made of:

Carbon steel

Wear resistant steel

Stainless steel

Plastic material

Buckets are made with bent and welded steel plates, properly reinforced with welded plates

in wear resistant material for heavy duty application, drawn or pressed for light materials.

The buckets are also available in various sections, which are listed below.

Square

V

Trapezoidal

Circular

Casing: It is the cover part of elevators which is made of welded and bolted sections,

designed to obtain a self supporting structure of the machine for the vertical loads. The

assembling sections are done by bolted flanges, with seals between each section. There is a

bolted door for easy bucket inspection and mounting.

Drive Unit: This configuration may vary depending on the application. The typical drive unit

for installed power of 22kW or more includes an electric motor, hydraulic coupling and right

angle gearbox with backstop and torque arm directly mounted on the drive shaft. Additional

8

electric motor for creeping can be installed, upon request, on the gearbox. As an alternative,

drive units can be equipped with a belt drive between electric motor and gear unit.

Take-Up: The gravity take-up system of the bucket elevators is equipped with additional

dust-tight seals between the casing and the guide of the idle shaft belt bucket elevators

realised for heavy duty application are equipped with a self aligning system which ensure the

safe parallel guidance of the pulley.

Method of Operation:

Bucket elevators operate by using an endless belt or chain on which rectangular buckets are

mounted. The belt or chain revolves between a top and bottom pulley and the buckets move

with it. At the bottom the buckets pick up product fed into the elevator boot and at the top the

product is discharged as the bucket turns downward over the head pulley.

1.3. CLASSIFICATION OF BUCKET ELEVATOR

Generally bucket elevators are classified in mainly two types.

Belt type bucket elevator.

Chain type bucket elevator.

Now a day there are many types of bucket elevators are available and each one is different

from other according to their feature, application, and design. The major classifications of

bucket elevators are as follows.

bucket elevator

according to

type of

discharge

positive

gravity

horizontal

centifugal

according

to types of

leg

single

twin

according

to types of

bucket use

single

double

depending

on load

low

medium

heavy

depending

on capacity

low

medium

heavy

9

1. Positive Discharge Bucket Elevator

These types of bucket elevators are widely used for elevating light, fluffy, fragile materials

like free flowing powders and granular products in a range of industries in vertical as well as

inclined position. Buckets are mounted at a well spaced interval, are loaded by digging

material from the boot or by feeding the material in to them. After passing over head wheels,

the buckets are inverted over the discharge spout, providing a positive discharge material.

Generally they have higher conveying capacity. Figure shows the typical diagram of positive

discharge bucket elevator.

Figure 1.5: Positive discharge bucket elevator

(Source: www.fmctechnologies.com and www.rexnord.com)

2. Gravity or Continuous Discharge Bucket Elevator:

In these types of elevators head shafts are fixed, the foot shafts takes up are screw type.

Gravity takes are available. This elevator consists of a series of steel made buckets mounted

on spigot pins between two chains or on the belt with the help of special types of screw. Also

some time the buckets are mounted continuously on the normally friction surface belts.

10

Continuous type steel buckets are used leaving minimum clearance between the buckets. The

buckets retain the material being carried and travelled vertically, until they are mechanically

tipped at discharge positions. Gravity discharge elevators supplied as close bucket discharge

type, central discharge type, or Idler wheel discharge. Generally a slow speed design gravity

bucket elevator is primarily installed for elevating large lumpy, free-flowing material,

sluggish material and abrasive material. Our standard units are usually chain driven, either

friction drive or toothed sprocket. These elevators offer reliability with minimum wear & a

positive discharge emptying of the bucket. The figure shows the vertical arrangement of

gravitational discharge bucket elevator.

Figure 1.6: Gravity discharge bucket elevator

(Source: www.integratedbulksystems.com.au and www.swrewconveyor.com)

3. Horizontal Discharge Bucket Elevator

These elevators are designed and engineered to conform to general practice in the handling of

grain. In particular they are found in flour mills and animal feed mills, where whole grain is

being transferred into intake silos. Also these types of bucket elevators are widely used for

11

elevating aggregate, hard rock, coal from mine in vertical horizontal as well as inclined

horizontal position. Head and foot shafts are provided with roller bearings. Buckets are made

of steel and mounted on the belt with special types of screw. Casing of steel are welded and

dust tight. The curve hood is designed for proper discharge of the grain. The boot can be

loaded from the front or back side or both. Generally they have higher conveying capacity.

Figure shows the typical diagram of horizontal discharge bucket elevator.

Figure 1.7: Horizontal discharge bucket elevator

(Source: www.ryson.com)

4. Centrifugal Discharge Bucket Elevator

Centrifugal elevators are the most common type of elevator installed to most industries

supplied in both belt type and chain type depending on material characteristic and the

capacity being elevated and in some case the feeding method of the elevator. Centrifugal

discharge type elevators are offered as boot take up and head take up. In this types of bucket

elevators buckets are mounted on chain or belt and will handle free-flowing materials with

small to medium size lumps. The standard inlet chute and standard curved bottom plate direct

the material into the buckets and reduce the “digging” action. The speed of the elevator is

12

sufficient to discharge the material by centrifugal force. The feed point is lower, loading is

simpler and fewer buckets are required than for the Continuous Type Bucket Elevator.

Buckets on chain or belt travel at speeds high enough to discharge materials by centrifugal

force as they pass around the head pulley or sprocket. Bucket spacing and speed is important

for centrifugal discharge bucket elevators. Usually buckets are made from malleable iron.

Generally these types of bucket elevators are more preferable in grain industries.

Figure 1.8: Centrifugal discharge bucket elevator

(Source: www.screwconveyor.com and www.go4b.com)

13

5. Twin Leg Bucket Elevator

The twin lagged or double trunk legging bucket elevator has been designed and engineered to

provide efficient high capacities for handling various grains, feeds, mill stock and similar free

flowing granular materials. The elevator is self-supporting with extra large heads and boot

pulleys. They are fabricated from heavy gauge steel and are dust and waterproof and with

provision for easy clean out. It is manufactured in many different sizes to suit individual

requirements. It has double trunk legging construction with connecting angles provided on

each 10 foot flange section. Vertical angle supports are included on taller units.

Figure 1.9: Twin legged discharge bucket elevator

(Source: www.screwconveyor.com, www.integratedbulksystems.com.au and www.rexnord.com)

14

6. Single and Double Bucket Elevator

The construction of these types bucket elevators are same as other types accept that the

number and types of buckets are use is different. The capacity of double bucket elevators is

more compare to single bucket elevator and also high capacity motor is required in operation.

The size of double bucket elevator is large compare to single bucket elevator since two

buckets are use in one raw as shown in figure. The double bucket elevators are used lift heavy

materials and also where, the higher output is required. Generally these types of bucket

elevators are used in aggregate plant, hard rock plant, cement plant where the lift of heavy

material is possible.

Figure 1.10: Single and double bucket elevator

(Source: www.screwconveyor.com and www.indiamart.com)

15

7. High or Super Capacity Bucket Elevator

Super capacity bucket elevators are a continuous discharge type with buckets mounted

between two strands of chain or on the belt. This type of elevator is used where higher

capacities, severe service or higher shaft centres are required. The high or super Capacity

Bucket Elevators are designed to provide efficient high capacities for handling various grains,

feeds, mill stock and similar free flowing granular materials. It is manufactured in many

different size stop suit individual requirements. It has double trunk legging construction with

connecting angles provided on regular interval flange section. Vertical angle supports are

included on taller units.

Figure 1.11: High or Super capacity bucket elevator

(Source: www.feedandgrain.com and www.screwconveyor.com)

1.4. APPLICATION OF BUCKET ELEVATOR

For stable work and application widely bucket elevator are used. By using this one should get

high Productivity. This bucket elevator is normally designed and made for metallurgy,

16

chemical industry, building materials, mine, pulp and paper industries, ports and terminal,

grain and vegetable oil, food, fodder, plastic and medicine related application. Bucket

elevator systems are used for the following industrial fields.

Cement factories: For lime, clay gypsum, clinker and cement additives like pyrite,

silicate, oxide etc

Environment and water treatment: Waste for combustion, biomass, sludge, ashes

etc.

Power plant: For coal, lignite and desulphurization product like gypsum, ashes,

sludge.

Fertilizers and Chemical: For raw materials and additives handling, phosphate,

nitrate.

Steelworks and Aluminium smelter: For coke, ashes, blast furnace slag, coke,

alumina, crushed bath, covers material.

Food industry: For sugar, flour, vegetables pulp, slaughterhouse waste etc.

Z type bucket chain material elevator is Suitable for lifting puffed food, fried food, nuts,

sugar, candy, hardware, medicines and so on. It is easy to operate fast transfer speed with low

noise. For grain or Seed application bucket elevator are used. This bucket elevator can be

equipped multi-channel explosion-proof mouth if required which can prevent dust explosion.

The system of speed monitoring, automatic running deviation alarm, anti-blockage alarm also

can be equipped to ensure the good running.

Reliable Quality Chain Bucket Elevator is designed and made for metallurgy, chemical

industry, building materials, mine, grain and vegetable oil, food, fodder, plastic and medicine

application. The life is long, inflow feeding, none excavating with hopper and there is few

extrusion and collision circumstance between materials. There is little materials sprinkling

during feeding and discharging to reduce machinery abrasion.

Structure Simple Bucket elevator is used for perpendicular transport the grain, powder and

disperse materials, and suitable for the oil, animal feed and chemical industry etc. This

Bucket Elevator is a fixed elevator categorized as feeding device of delivering powdery and

granular materials upward vertically. It has simple structure, smaller cover are, short

17

shipping route and low pollution. Wood chips are received from belt conveyor by a double

led centrifugal discharge bucket elevator and delivered to a distributed belt conveyor over

silos.

1.5. PRESENTLY INSTALLED BUCKET ELEVATORS IN ABROAD:

Bunge Russia recently opened a new oilseed extraction facility featuring Brock steel bins.

Figure 1.12: Bunge Russia – Oilseed bucket elevator

(Source: www.World-Grain.com)

Chief Industries installed two bins to increase storage capacity by 16,000 tonnes at this plant

in New Zealand.

Figure 1.13: New Zealand - Bins plant bucket elevator


Bucket elevator

Bucket elevator

18

Cimbria recently installed bins with a combined storage capacity of 333,000 tonnes at seven

facilities in Egypt.

Figure 1.14: Cimbria (Egypt) - Bins plant bucket elevator


Figure 1.15: Bahrain - Coke calcining plant


Bucket elevator

19

Figure 1.16: Jordan - Fertilizer plant


20

Chapter 2: DESIGN OF BUCKET ELEVATOR

2.1. BUCKET ELEVATOR GEOMETRY:

Pole Distance:

Figure 2.1: Diagram to calculate the pole distance

(Source: Spivakovsy, A.O. and Dyachkov, V.K. (1985), Conveying Machine, MIR Publication,

Forth Edition)

As a bucket revolve on the pulley, the resultant R of the forces P and F varies in magnitude

and direction. If however, the resultant force vector is prolonged to the vertical line passing

through the pulley centre, it turns out that at any position of the bucket, and vector R

intersects the vertical in one and the same point B to the pulley centre O is called the pole

distance. The pole distance is denoted by hP.

Bucket Unloading:

At lower speed of the pulley, the effect of the gravity force on unloading become stronger

and hP increases. When hP is not larger than rP the pole is inside the pulley circle (figures 2.2a

and 2.2b), the centrifugal force is much higher than the gravity force and hence bucket

unloading centrifugally.

21

(a) Centrifugal unloading; (b) gravity unloading; (c) Combined unloading

Figure 2.2: Forces acting during bucket unloading


Forth Edition)

Similarly if hP grater than rP the force of gravity is large and buckets are unloaded

gravitationally. With rP < hP ≤ ra unloading of combined types takes place. Therefore, the

method of unloading is determined by the ratio between the pole distance and pulley radius

A= hP /rP .

Trajectory of Partials Discharged From a Bucket:

Figure 2.3: Diagram to determine the paths of ejection of material from buckets


Forth Edition)

22

As a bucket moves around the top pulley, a particle of load in it is acted upon by the gravity

force, centrifugal force, and inertia force due to the relative acceleration of sliding the particle

on the bucket wall.

The path and velocity νS of sliding particle can be determined by solving equation of motion

of the particle. The start of the motion of the particles depends on the method of unloading.

With centrifugal discharge the load beings to move in the bucket at an angle β0 = 15-300. For

elevators with centrifugal or combined unloading, it may be taken that β0 = 30-450

2.2. DESIGN INPUT DATA FOR BUCKET ELEVATOR:

Assumption:

During design of bucket elevator a few factors are consider for design and based on this for

input data whole design calculations were carried out. The following factors are considered

during design.

Material for lifting: Wheat

Average bulk density: 720-768 Kg/m3

Application: In flour mills to transmitting large amount of wheat from ground floor

to required destination (floor).

Properties of material: Lighter than metal, Injection moulded, Flexible, Thick

corners and digging lip.

Specific requirements: It should have excellent chemical resistance and it should

have higher transmission capacity.

Calculation:

Capacity (Q) = 30.00 Tonne/hour

Lifting height (H) = 3.00 m

Wheat density (ρ) = 0.768 Tonne/m3

23

1. THE MAIN CHARACTERISTICS OF THE ELEVATOR

By using Table 2.1 a belt elevator with widely spaced deep buckets and belt speed ν = 3.20

m/s is suitable for the transmission purpose. We select a four-ply belt; then the diameter of

the drive pulley is given by DP = 125 * 4 = 500 mm = 0.50 m and its radius rP = 0.25 m. The

rotational speed of the pulley at ν = 3.20 m/s is given by,

N =60.00 ν

(π Dp)

=60.00 ∗ 3.20

(π ∗ 0.50 )

= 122.23 rpm

≈ 122.00 rpm

The pole distance hp is found by the formula,

hp =g r2 30.002

π2 r2 N2

=895.00

N2

=895.00

122.002

= 0.06 m

Table 2.1: Recommendation for selecting bucket elevators

KIND

OF

LOAD

TYPICAL

EXAMPLE

TYPE

OF ELEVATOR

TYPE

OF

BUCKET

AVERAGE

COEFFICIENT

OF BUCKET

FILLING

SPEED m/s

OF

BELT CHAIN

DRY

PULVERIZED

MATERIAL

PULVERIZED

COAL

LOW SPEED

GRAVITY

UNLOADING

D 0.85 - 0.6 - 0.8

CEMENT, ROCK,

PHOSPHET MEAL

HIGH SPEED

CENTRIFUGAL

UNLOADING

D 0.80

1.25 - 2.0 -

GRAIN

PRODUCTS

(FLOUR)

HIGH SPEED

CENTRIFUGAL OR

GRAVITY

UNLOADING

S

0.85

1.0 - 2.0

-

FOOD GRAIN

HIGH SPEED

CENTRIFUGAL OR

GRAVITY

UNLOADING

D 0.75 2.0 - 3.2 -

24

GRANULAR

AND FINE -

LUMP, LOW

ABBRASIVE

SAWUST, WOOD

CHIPS, DRY

CLAY IN LUMPS,

MILLED PEAT,

FINE COAL

DITTO D 0.8 1.25 - 2.0 1.0 – 1.6

LIME, SOOT

LOW SPEED

GRAVITY

UNLOADING

D 0.8 - 0.4 – 1.0

PULVERIZED

AND

GRANULAR,

WET

POORLY

FLOWING

SOIL, SAND,

POWDER CHALK,

CHEMICALS

HIGH SPEED

CENTRIFUGAL OR

GRAVITY

UNLOADING

S 0.6 1.0 - 2.0 0.8 – 2.0

(Note: Bucket types: D: Deep, S: shallow)


Forth Edition)

At lower speeds of the pulley the effect of the gravity force on unloading becomes stronger

and hp increases. Now when hp is not longer than rp, i.e. the pole is inside the pulley circle as

shown in figure 2.1, the centrifugal force is much higher than the gravity force; particles of

the material in a bucket are displaced to the external (front) of the bucket and later are

unloaded centrifugally. With hp greater than rp i.e. with the pole being the front edge of

buckets as shown in figure the force of gravity is large compared with the centrifugal

component and the buckets are unloaded by gravity over their back wall (closest to the

pulley). Since hp<rp the buckets can be unloaded centrifugally. Therefore the method of

bucket unloading is determined by the ratio between the pole distance and pulley radius. Now

by using Formula at Ψ = 0.75 we have,

io tb =𝑄

3.60 ν ρ Ѱ

=30.00

3.60 ∗ 3.20 ∗ 0.768 ∗ 0.75

= 4.52 m−1

25

(Note: Buckets types: M: Shallow, D: Deep, V: V-shaped, R: Round bottom)

Figure 2.4: Effect of bucket width B on io/tb ratio


Forth Edition)

Now by referring Table 2.2, we chose for io/ tb = 5.0 deep type buckets with Bucket width (B)

= 250 mm, Volume (V) = 21.00 mm3, Belt width (Bb) = 300 mm, Bucket pitch (tb) = 400 mm

and also io = 2.0 lit.

With these characteristics of buckets and the belt speed 3.20 m/s, the rated throughout

capacity of 30 t/h can be obtained at the coefficient of bucket filling,

26

Table 2.2: Main characteristics of buckets

Bucket

width B

mm

Belt width

Bb for

belt elevator

mm

Pitch

of

widely

spaced

bucket

tb mm

Deep bucket

type

D

Deep bucket

type

S Pitch

of

closely

spaced

bucket

tb mm

Bucket with side guide

1st

Raw

2nd

raw

io

lit

io/tb

m-1

io

lit

io/tb

m-1

V - shaped

type

V

Round

bottom

type R

io

lit

io/tb

m-1

io

lit

io/tb

m-1

100 125 - 200 0.2 1.0 0.1 0.5 - - - - -

125 160 150 220 0.4 1.3 0.2 0.66 - - - - -

160 200 - 320 0.6 2.0 0.35 1.17 160 0.65 4.06 - -

200 250 - 400 1.3 3.24 0.75 1.87 200 1.3 6.5 - -

250 300 315 400 2.0 5.0 1.4 3.5 200 2.0 10.0 - -

320 370 400 500 4.0 8.0 2.7 5.4 250 4.0 10.0 6.4 25.6

400 450 500 500 6.3 12.6 4.2 8.4 320 7.8 24.4 14 43.7

500 550 600 630 12.0 19.0 6.8 10.8 400 - - 28 70

650 700 - 630 16.8 26.0 11.5 18.2 500 - - 60 120

800 - - - - - - - 630 - - 118 187

1000 - - - - - - - 630 - - 148 235

(Note: Bucket types: D: Deep, S: shallow)

Source: Spivakovsy, A.O. and Dyachkov, V.K. (1985), Conveying Machine, MIR Publication,

Forth Edition)

Ѱ =Q t

b

3.6 ν ρ io

=30 ∗ 0.4

3.6 ∗ 3.20 ∗ 0.768 ∗ 2.0

= 0.678

Which is possible to reduce the speed to 1.36 m/s but it is substandard and cannot ensure

centrifugal discharge.

27

2. LINEAR GRAVITY FORCE

The linear mass of the belt with four-ply of material like rubber ground is given by, mrb =

2.40 m/s then,

qrb

= g mrb

= 9.81 ∗ 2.40

= 23.54 N/m

≈ 24.00 N/m

The mass of standard deep bucket of Bucket width (B) = 250 mm, is given by mb = 3.38 Kg

than,

qo

= qrb

+ g mb

tb

= 24.00 + 9.81 ∗3.38

0.4

= 106.89 N/m

The useful load is given by,

ql

=g Q

3.60 ν

=9.81 ∗ 30.00

3.60 ∗ 3.20

= 25.55 N/m

Then the total linear gravity force acting on the carrying runs is given by,

q = qo

+ ql

= 106.89 + 25.55

= 132.44 N/m

28

3. PULL CALCULATION

(a) Elevator scheme; (b) Diagram of belt tension

Figure 2.5: Diagram for elevator calculation

Source: Spivakovsy, A.O. and Dyachkov, V.K. (1985), Conveying Machine, MIR Publication,

Forth Edition)

According to the diagram of tension Figure 2.5(b), the lowest tension of the belt should be

expected at point 1. We can make only a rough calculation, since we do not know the tension

T4 in the belt section running off the drive pulley as required to ensuring the rated pull. We

assume that T1 = T0. The tension at point 2 is found by considering the resistance on take-up

pulley and the scooping resistance by formula for heavy-duty operation ζ = 1.08 and Ksc = 2.0

T2 = ζ T1

+ Wsc

= ζ T1

+ Ksc ∗ ql

= 1.08 ∗ T0 + 2 ∗ 25.55

= 1.08 ∗ T0 + 51.10

29

T3 = Ton = T2 + q H

= 1.08 ∗ T0 + 51.1 + 132.44 ∗ 3

= 1.08 ∗ T0 + 448.42

Calculation against the direction of belt motion gives,

T4 = Toff = T1 + H qo

= T0 + 106.89 ∗ 3

= T0 + 320.67

According to theory of frictional drives we have,

π = sin−1

Dp − dp

2 C

= sin−1

0 ... (Since Dp = dp)

= 0

Now angle of contact/arc of contact/angle of lap is given by

θ = π + 2 ∗ 0

= π rad

Ton ≤ Toff ∗ eμθ or for the case considered T3 ≤ T4 ∗ eμθ

For a mild steel pulley and high humidity (the elevator operates outdoor), the friction

coefficient μ = 0.35, so that at θ = п rad. Therefore eμθ

= 3.00. Hence, T3 ≤ 3.00 ∗ T4 or for

the case considered

1.08 ∗ T0 + 448.42 ≤ 3.00(T0∗ 320.67)

Solution of this equation gives T0 >> - 267.49 N. To ensure the certain margin, we take T0 = 0

N and then,

30

T4 = Toff = T0 + 320.67

= 320.67 N

≈ 321.00 N

T3 = Ton = 3.00 ∗ T4

= 3.00 ∗ 320.67

= 962.01 N

≈ 962.00

The required number of belt plies is found for Kop = 55 N/mm and safety factor K = 10

i =K Smax

Bb Kop

=10 ∗ 962.00

30 ∗ 55.00

= 0.58

Noting that belt is weakened by bolts and should ensure firm fastening of buckets, we can use

the four-ply belt adopted earlier in the calculation. The circumferential force on the drive

pulley, noting the pulley resistance is,

W =T3 − T4

ζ

=962.01 − 320.67

1.08

= 596.83 N

= 564.00 N

The power of drive motor, assuming the efficiency of drive mechanism η = 0.85 and a margin

K = 1.25, will be

P =K ν W

1000 η

31

=1.25 ∗ 593.83 ∗ 3.20

1000 ∗ 0.85

= 2.79 kW

≈ 2.8 kW

Hearse, we take finally a drive motor of a power P = 2.8 kW and rotational speed N = 51.95

rpm

4. PULLEY CALCULATION

Width of the pulley is given by,

Bp = 1.25 Bp

= 1.25 ∗ 300

= 375.00 mm

Thickness of rim is given by,

t = Dp

200 + 2

= 500

200 + 2

= 5.5 mm

≈ 6.0 mm

5. BELT CALCULATION

Length of belt is given by,

L = 2 H + π (Dp + dp)

2+

(Dp − dp)2

4+ C

= 2 ∗ 3.00 + π ∗(0.512 + 0.512)

2+

(0.512 − 0.512)2

4+ 3.00

= 7.60 m

32

Belt Tension,

T = T3 − T4 Dp

2

= (962.01 − 320.67) ∗0.50

2

= 160.34 Nm

≈ 160.00 Nm

Permissible Tension in belt per mm width (f),

f =T3

Bb

=962.01

300

= 3.21 N/mm

6. SHAFT CALCULATION

For 300 mm belt width and 500 mm pulley diameter, Diameter of shaft (d) is 83 mm.

Allowable shear stress for shaft and key material (mild steel), τsk = 70.4 N/mm2 then,

allowable shear stress for shaft accounting keyway effect,

τs = 0.75 τsk

= 0.75 ∗ 70.4

= 52.80 N/mm2

Now, Equivalent torque acting on shaft,

Te = τsk π d3

16

= 52.8 ∗π ∗ 833

16

= 5998.85 ∗ 103 Nmm

33

= 5.9 KN m

Width of key,

w = d

4

= 83

4

= 20.83 mm

≈ 21.00 mm

Height of key,

h =2 w

3

=2 ∗ 21

3

= 13.89 mm

≈ 14 mm

Length of key = 22 mm and radius of hub is equal to diameter of shaft so, rh = 83 mm

7. BEARING CALCULATION

By using series: 60

Inner diameter: d = 83 mm

Outside diameter: D = 130 mm

Width of bearing: b = 23 mm

Static load: Co = 42 KN

Dynamic load: C = 49 KN

Permissible rpm for grease = 5187.5 rpm and

For oil = 6536.25 rpm

34

8. BUCKET CALCULATION

Figure 2.6: Diagram for bucket calculation

(Source: www.maxilift.com)

By using Table 2.3 given by

Depth of bucket, h1= 156.00 mm

Projection of Bucket, b= 156.00 mm

Table 2.3 Recommendation for selecting bucket Dimension by Maxi-lift

Width of Bucket

B, mm

Projection of Bucket

b, mm

Depth of Bucket

h1, mm

108 79 79

133 105 105

159 105 105

184 105 105

181 130 133

206 130 133

232 130 133

238 156 156

264 156 156

289 156 156

(Source: www.maxilift.com)

35

Now, assume β=18˚

h1 − h2 = b tan 18°

= 156 ∗ 0.325

= 50.70 mm

h2 = h1 − (h1 − h2)

= 156.00 − 50.70

= 105.30 mm

≈ 105.00 mm

Therefore, Number of buckets = Belt length Bucket pitch

= 7.60 0.40

= 19

2.3. FLOW CHART FOR CODING OF DESIGN

Start

Lifting Height (H) in m =

Wheat Density in Tonne/m3 =

No. of Belt ply (Np) =

Efficiency =

36

Want to enter

Capacity (Q)?

No Yes

Yes No Want to enter Pulley

diameter?

Capacity (Q) t/hr =

I0/tb = Q / (3.60 * v * ρ * Ψ)

Enter i0/tb in m-1

Q = i0/tb * 3.60 *v * ρ * Ψ

Pulley Diameter (Dp)

mm

Dp = 125 * No. of Belt ply

rp = Dp / (2000), m

Belt velocity (V) = 3.2 m/s

N = 60 * v * 1000 / (п * Dp), rpm

hp = 895 / (N2)

hp < rp

Stop

Unloading of bucket

centrifugally is not possible

Unloading of bucket centrifugally is possible

No

Yes

Bucket width (B) in mm

Belt width (Bb) in mm

Bucket pitch (tb) in mm

Bucket volume (V) = (21* B) / 250 mm3

37

mrb = 2.4 * Np / 4;

qrb = 9.81 * mrb;

mb = 3.38 * B / 250;

q0 = qrb + (9.81 * mb * 1000 / tb);

Tension T4 in N = q0*H;

Tension T3 in N = 3.00*T4

Safety factor k = 10

Required no. of belt plies (i) = k * T3 / (Bb * 55);

Pulley Resistance (W) in N = (T3 - T4) / 1.08

Motor power (P) in kW = 1.25 * W * 3.2 / (1000 * Efficiency)

Pulley width (Bp ) in mm = 1.25 * Bb

Rim thickness (t ) in mm = Dp / 200 + 2

Belt length (L) in m = 2 * H + (3.14 * Dp / 1000)

Belt tension (T) in Nm = (T3 - T4) * Dp / 2

Permissible Tension (f) in belt per mm width in N/mm = T3 / Bb

Projection of bucket (b) in mm

Depth of Bucket (h1) in mm

(h1 - h2) = b * tan(18)

h2 = h1 - (h1 - h2), mm

n = L * 1000 / tb

38

Shaft diameter (d) in mm

Shaft load in kN

Bearing No.

Bearing bore diameter in mm

Bearing outside diameter in mm

Bearing width in mm

Bearing static load (C0) in kN

Bearing dynamic load (C) in kN

Permissible rpm for Grease lubrication

Permissible rpm for Oil lubrication

Radius of hub (rh) in mm

Key width (w) in mm

Key height (h) in mm

Equivalent torque acting on shaft (Te) in Nmm

Stop

39

Chapter 3: MODELING OF ELEVATOR

3.1. INTRODUCTION OF MODELING AND ITS SIGNIFICANE

Modeling is defined as the complete representation of an object or a system with the

graphical and non graphical information. It is also known as geometric modeling. It generates

the mathematical description of the geometry and non geometry of an object or a system in

the computer database and the image of an object or system on the graphic screen. With the

use of modeling the designer constructs the graphical image of an object on the computer

screen with the use of following three types of commands to the computer.

1. Generates basic geometric elements such as points, lines and circles etc.

2. To accomplish scaling, rotation or other transformation of various elements.

3. Which cause various elements to be joined?

There are various types of drawing required in different field of engineering and science. In

the field of mechanical engineering, the drawing of machine components and layouts are

prepared. In the field of civil engineering, plans and layouts of power distribution system are

prepared. The use of CAD process provides enhance graphics capabilities which allows any

designer to,

1. Conceptualize his/her ideas

2. Modify the design very easy

3. Perform animation

4. Make design calculations

5. Use colours, fonts and other aesthetic features.

Significance of modeling is as follows:

1. It makes the model a true replica of actual objects.

2. As the model is stored in mathematical form, the model modification can be carried

out easily.

3. A geometric model can be use to evaluate the various properties of an actual objects.

4. A geometric model provides a sophisticated tool for 3D visualization of the objects.

40

5. A geometric model can be easily converted in to the two-dimensional views.

6. A geometric model can be used by Pro/Engineer software to perform the different

types of analysis such as: stress-strain analysis, kinematic analysis, dynamic analysis,

thermal analysis etc.

7. A geometric model can be used by the CAM software to generate a complete tool

path required for the automatic manufacturing.

3.2. CAD PARTS OF BUCKET ELEVATOR:

The important parts of bucket elevator are as under,

1. Bucket

Command used:

Extrude 1: Make solid cube of 250 x 156 x 156 mm.

Extrude 2: Draw side view of bucket on Extrude 1 and remove excess material.

Shell 1: Remove inside material of Extrude 2, so finally bucket shape is generated.

Pattern 1 of hole 1: Make one hole of 15 mm diameter and done direction pattern for

75 mm distance.

Function:

Buckets are used to carry grain material from bottom to top.

Figure 3.1: Bucket Figure 3.2: Ball bearing

41

2. Ball bearing

Command used:

Revolve 1: Generate sphere of 4.27 mm radius by using revolve command.

Revolve 2: Generate Bearing inside and outside ring shape of 83 mm inside diameter

and 130 mm outside diameter of 23 mm width.

Assembly: Finally done assembly of sphere and bearing ring shape assembly and put

16 spheres between inside and outside ring by using axis pattern. So finally Bearing is

generated.

Function:

Bearing is used to reduce friction and to convert sliding contact in to rolling contact.

3. Belt:

42

Figure 3.3: Belt

Command used:

Extrude 1: Make side part of belt and Extrude it up to 300 mm, So finally Belt shape

is generated.

Pattern 1 of hole 1: Draw first hole of 15 mm diameter and done curve pattern at 400

mm distance.

Pattern 2 of hole 2: Draw second hole of 15 mm diameter at distance 75 mm to first

hole and done curve pattern at 400 mm distance.

Pattern 3 of hole 3: Draw third hole of 15 mm diameter at distance 150 mm to first

hole and done curve pattern at 400 mm distance.

Function:

Belt is used to carry bucket and drive driven pulley (bottom pulley) by using driving

pulley (top pulley).

4. Shaft

Figure 3.4: Shaft

Command used:

Extrude 1: Draw 83 mm diameter circle and extrude it up to 600 mm length. So

finally shaft shape is generated.

43

Extrude 2: Draw cube of 22 x 21 x 17 mm on shaft at 143 mm distance from centre to

both side on opposite axis and done Extrude remove material to generate key way on

shaft.

Function:

Shaft is used to transmit power, motion and torque.

5. Pulley

Figure 3.5: Pulley

Command used:

Extrude 1: Generate 22 x 21 x 14 mm cube as key.

Assembly 1: Put key on shaft key way and made shaft-key Assembly.

Revolve 1: Generate hub shape of 166 mm outside radius and 83 mm inside radius

with 48 mm total height and revolve it to get hub rough shape.

Round 1: 5 mm fillet action are done at end of hub shape for its smoothness.

Extrude 2: Generate cube of 8.63 x 21 x 45 mm cube is generated on inside part of

hub shape and done Extrude remove material to generate key way in hub.

Assembly 2: Combine hub and shaft-key assembly.

Assembly 3: Put Bearing inside hub in previous done assembly.

Extrude 3: Draw ring of 83 mm inside diameter and 130 mm outside diameter and

extrude it to 6 mm, to generate bearing cover.

Assembly 4: Assemble bearing cover on bearing in Assembly 3 outcome.

44

Extrude 4: Draw ring of 142 mm inside diameter and 500 mm outside diameter and

extrude it to 6 mm, to generate pulley cover plate.

Assembly 5: Assemble pulley cover plate on hub in Assembly 4 outcome.

Extrude 5: Generate 500 mm inside diameter, 6 mm thickness and 375 mm pipe as

pulley rim.

Assembly 6: Assemble pulley rim on cover plate in assembly 5 outcome, so finally

get Pulley.

Function:

Pulley is used to transmit power, motion and torque from one shaft to another shaft by

using belt.

3.3. ASSEMBLY OF BUCKET ELEVATOR:

Used Top to Bottom assembly approach to assemble bucket elevator as shown in figures

earlier. Various steps includes in assembly of bucket elevator are as followed. The final

figure of assembly of bucket elevator is shown in figure 3.6

Assembly 1: First call pulley at top and give fix constrain to it and take direction

pattern of the same at distance of 3000 mm

Assembly 2: Call belt and fix it on two pulleys.

Assembly 3: Call buckets and fix it on belt by using nut bolts, And finally done curve

pattern of bucket at 400 mm distance to get final bucket elevator assembly.

45

Figure 3.6: Bucket elevator assembly

3.4. BILL OF MARERIAL

Table 3.1: Bill of material for bucket elevator

Serial Number Quantity Description Material

1. 19 Bucket Mild steel

2. 1 Belt Rubber

3. 2 Pulley Mild steel

4. 4 Bearing Stainless steel

5. 4 Hub Mild steel

6. 4 Key Mild steel

7. 4 Cover plate Mild steel

8. 2 Shaft Mild steel

3.5. MECHANISM OF BUCKET ELEVATOR

The mechanism of bucket elevator is prepared by performing various stapes for that it

required various joints between two respective parts. Joints required for mechanism is applied

46

during assemble the parts. Various joints required for mechanism are pin joint, sliding joint,

belt joint. The detail procedure for mechanism is discussed under with the required figure.

First off all call the support on which the driving or driven pulley is going to be fixed

and apply fixed constrain on it and take the direction pattern of the same at required

distance.

Call the driven pulley and assemble it with lower end support by pin joint. Same

procedure is followed during assemble of driving pulley.

Than call the belt bucket assembly and assemble it on outer surface of the pulley by

sliding joint.

Now go to the mechanism and apply the servomotor between the pin joint of support

and driving pulley and give required input for rotation of servomotor in servomotor

definition as shown in figure 3.7

Figure 3.7: Mechanism of bucket elevator

Click on the analysis definition and select the type of analysis also give the required

input for respective analysis and run it. Here we select the kinetic analysis.

During mechanism of belt elevator various problem occurred due to sliding joint of belt and

pulley. Such problems occurred during mechanism are as under.

47

Problem: 1

From the figure 3.8 both pulleys are assembled by pin joint and belt is assembled by sliding

joint, but during running of mechanism the driven pulley joint is suppressed and remain

steady and driving pulley is rotate with belt like a clock hand.

Figure 3.8: Mechanism problem-1 of bucket elevator

Problem: 2

From the below figure 3.9 both pulley are assembled by pin joint and belt is assembled by

sliding joint, but during running of mechanism one pulley joint is suppressed and driven

pulley remain steady and driving pulley is rotate but the belt slides out from the both pulley

surface.

Figure 3.9: Mechanism problem-2 of bucket elevator

48

To solve these problems, A belt drive as a case study is considered and parts are modeled

using Pro/Engineer and the same problems are persisting in that assembly of mechanism. But

same problem occurred during the mechanism of belt joints. In short the simulation of the

belt-pulley system using Pro/Mechanism yet to be work out for its implementation in bucket

elevator mechanism.

Fig. 3.10: Mechanism problem in case study

49

Chapter 4: FABRICATION OF PROTO TYPE

4.1 SELECTION OF PROTOTYPE DIMENSION:

Selection of dimension for prototype model is based on the input and output parameter of the

C program shown in Appendix: A. The input and output data for the dimension of prototype

model is shown in following tabular format.

Input data:

Table 4.1: Design inputs for prototype model

Lifting Height (H) - m 1

Wheat Density (ρ) - Tonne/m3 0.768

Number of belt ply 4

Efficiency 0.85

Want to enter Capacity (Q)? (Y/N) N

Enter value of i0/tb (1.3, 2.0, 3.24, 5.0, 8.0) - m-1

2.0

Want to enter Pulley diameter (Dp)? (Y/N) Y

Pulley diameter (Dp) - mm 200

Output data:

Table 4.2: Design outputs for prototype model

Capacity (Q) - Tonne/hr 13.271040

Pulley radius (rp) - m 0.1

Belt velocity (v) - m/s 3.2

Rotation speed of pulley (N) - rpm 305.732483

Pole Distance (hp) - m 0.001875

Unloading of bucket centrifugally is possible? Y

Bucket width (B) - mm 160

Belt width (Bb) - mm 200

50

Bucket pitch (tb) - mm 320

Bucket volume - mm3 13.44

Tension (T3) - N 234.262802

Tension (T4) - N 78.087601

Required no. of belt plies 0.212966

Pulley Resistance (W) - N 144.606674

Motor power - kW 0.783039

Pulley width (Bp) - mm 250.000000

Rim thickness (t) - mm 3.000000

Belt length (L) - m 2.628000

Belt Tension (T) - Nm 17971.919922

Permissible Tension (f) in belt per mm width - N/mm 1.347894

Projection of bucket (b) - mm 79

Depth of Bucket (h1) - mm 79

h2 mm 47.80

No. of bucket (n) 8.212500

Shaft diameter (d) - mm 30

Shaft load - kN 6

Bearing No. 6006

Bearing bore diameter - mm 30

Bearing outside diameter - mm 55

Bearing width mm 13

Bearing static load (C0) - kN 8.30

Bearing dynamic load (C) - kN 13.30

Permissible rpm for Grease lubrication 12000

Permissible rpm for Oil lubrication 15000

Radius of hub (rh) - mm 30

Key width (w) - mm 7.500000

Key height (h) - mm 5.000000

Equivalent torque acting on shaft (Te) - kNm 0.279774

51

4.2. FABRICATION OF BUCKET ELEVATOR PROTOTYPE

After getting the above program output for prototype model design, fabrication of the model

is carried out. Various processes involved in fabrication of the prototype model are as under.

Table 4.3: Fabrication processes for bucket elevator

1. Cutting

2. Marking

3. Punching

4. Drilling

5. Facing

6. Centering

7. Turning

8. Chamfering

9. Gas cutting

10. Grinding

11. Welding

12. Bending

13. Chipping

14. Boring

15. Slotting

The procedure followed for the fabrication of model is as followed:

For support structure:

1. Cut the L - channel, flat stripes of required height and length for the structure.

2. Marking and punching on each channel and flat stripes as per need of location of hole.

3. Drill on each punching location as per requirement of hole diameter with the help of

drilling machine with respective drilling tool of 10 mm and 12 mm diameter.

4. By using bolts of 12 mm and 10 mm diameter at required hole joining various

sections and make whole structure.

For pulley shaft:

1. Cut the 32 mm diameter shaft as per the requirements of length.

2. Face the both end of shaft on lathe and centre on each end with the drilling tool.

3. Turning the whole shaft (both shaft) of 30 mm diameter.

4. Chamfer the each end of the shaft.

For pulley:

1. Cut the 200 mm diameter, 6 mm thick pipe in two equal lengths of 250 mm for pulley

rim.

2. According to the inner diameter of the pipe cut the four round circles for cover plate

with the help of gas cutting.

52

3. Grind the outer surfaces of the plates to match with the inner surface of pulley rim.

4. Drill the hole of 30 mm diameter on centre of each cover plate.

5. Weld the cover plates on both shafts; two cover plates on each shaft.

6. Fix the pulley rim on shaft-cover plate assembly at required position and make just tag

welding.

7. Check the proper fixing the pulley rim on the shaft-cover plate assembly carried out

the full welding.

For buckets:

As per the calculation of the requirements of bucket, calculate the plate size of by developing

the whole bucket as shown in figure 4.1 & 4.2 and calculate the area of sheet required for the

one bucket. Prepare a bucket sheet metal planning for all buckets which is shown in figure

4.3.

1. As per the bucket sheet metal planning makes a marking on sheet.

2. Cut the plates in required shape for side parts (small in size) and bend parts (large in

size) of the bucket with the help of tin snip.

3. Bend the large size of sheet in bending machine.

4. Cut the side parts (small in size) of the bucket in required shape.

5. Weld the bend parts of bucket with side parts.

6. Carried out grinding operation for batter surface finish.

7. Marking and punching on the surface on which the buckets are going to be bolt on the

belt and drilling on that desired location with required drill tool.

Calculation for material utilisation is as follows (Refere figure 4.3),

53

Figure: 4.1: Side part of bucket

Figure: 4.2: Bend part of bucket

Figure: 4.3: Sheet metal planning for all bucket

54

Area of front part, A = 231.13 ∗ 164

= 38889.32 mm2

Area of front part, A = 105 ∗ 105

= 11025 mm2

Total area of front part and side part is 9A mm2 and 18B mm

2 respectively. Now total

material used is given by,

C = 9A + 18B

= 9 ∗ 38889.32 + (18 ∗ 11025)

= 548453.88 mm2

Total area available of sheet, D = 1800 + 750

= 2550 mm2

Now, material utilization factor is given by,

MUF = Area used

Total area available=

C

D

= 548453.88

2550

= 40%

From the above calculation it is cleared that, only 40% of sheet is used from the whole sheet.

So, in place of using whole sheet, use of scrap of particular size is advisable and also

economical.

For belts:

1. Marking on the belt for fixing the buckets at required bucket pinch distance.

2. Mark the holes position on this bucket pitch distance.

3. Punching on that holes location with the help of dot punch.

4. Drill the all punched marks on belt with hand drilling machine.

55

Assemble the all parts which are fabricated earlier with the help of suitable joints like nut-bolt, weld

etc. the final picture of bucket elevator is shown in figure 4.4.

4.3. SELECTION OF POWER PULLEY

To reduce the motor speed up to 305 rpm, it is necessary to use an extra pulley (power

pulley) in conjunction with upper shaft of bucket elevator. For that calculation is necessary,

calculation for speed reduction is given below.

𝐷

𝑑=

𝑛

𝑁

Where,

D = Diameter of top power pulley attach with upper pulley of bucket elevator

d = Diameter of bottom power pulley attack with motor

N = Top power pulley speed = 305 rpm

n = Bottom power pulley speed = 1400 rpm

𝐷

𝑑=

1400

305

= 4. 59

To get this Diameter ratio, take D = 22.86 cm = 9 inch and d = 5 cm = 1.96 inch ≈ 2 inch

4.4. BENDING MOMENT DIAGRAM FOR UPPER SHAFT

Bending moment at point X and B are,

Mx = Ra(170)

= 4076.95 Nmm

Mb = 18.639 210

= 391.42 Nmm

56

Bending moment diagram is shown in figure 4.4. Now, calculation for required length of v

belt is shown as under.

C = Distance between two pulleys = 89 cm

D = Diameter of top power pulley attach with upper pulley of bucket elevator = 22.86 cm

d = Diameter of bottom power pulley attack with motor = 5 cm

Figure: 4.4: Loading and bending moment diagram for upper shaft

57

Now,

L = 2C +π(D + d)

2+

(D − d)2

4C

= 2(89) +π(22.86 + 5)

2+

(22.86 − 5)2

4(89)

= 222.656 cm

= 87.65 inch

4.5. PROBLEMS OCCURE DURRING FABRICATION

The following problems ware faced during the fabrication of prototype model of bucket

elevator.

1. Due to spring back effect in bucket sheet material, Elastic recovery occurs when press

machine pressure is released. It is depends on type of material, thickness of material,

band radius and band angle.

2. For pulley, used hollow pipe of 200 mm diameter, 6 mm thickness as pulley rim, this

is slightly oblong during turning process. So to overcome this problem made pulley

assembly like fabricated shaft, cover plate and pulley rim, than again done turning on

pulley rim.

3. Purchased shaft from scrap so doesn’t know about its material property. Because of

this purchased harden shaft’s machining is not possible. So replaced it by purchasing

new shaft to get desired property of shaft material so once can machined it properly

with in limited constraints.

4. Delay in getting of belt and pulley machining (Done outside due to less capacity of

machine of ADIT workshop).

5. Problem due to pulley shaft alignment, Because of this belt is comes outside form

pulley. To avoid this weld required thickness of strips or flange on pulley so that belt

is fitted in required space and run within specific path.

58

4.6. FABRICATED PROTOTYPE OF BUCKET ELEVATOR

Figure: 4.5: Fabricated bucket elevator prototype model

59

Chapter 5: RESULTS ANALYSIS

5.1. EFFECT OF OPERATING VARIABLES

For the purpose of handling, the effects of various operating conditions are being studied

theoretically for working of bucket elevator.

Effect of lifting height on number of bucket, motor power and belt length:

Assume capacity (Q) = 30 Tonne / hr and Pulley Diameter (Dp) = 500 mm as constant, than

the effect of lifting height on number of bucket, motor power and belt length is shown in

graph bellow. As the lifting height of bucket elevator increases the number of bucket, motor

power and belt length is gradually increases (Refer figure 5.1).

Figure 5.1: Variation based on lifting height

3 m 6 m 9 m 12 m 15 m

No. of Bucket 19 34 49 64 79

Motor Power (kW) 2.8 5.6 8.4 11.2 13.9

Belt Length (m) 7.6 13.6 19.6 25.6 31.6

0

10

20

30

40

50

60

70

80

90

60

Effect of pulley diameter on speed, belt length, number of bucket, and shaft diameter:

Assume lifting height (H) = 3 m and capacity (Q) = 30 Tonne / hr as constant, than the effect

of pulley diameter on speed, belt length, no. of bucket, and shaft diameter is shown in graph

bellow. As the pulley diameter of bucket elevator increases the rotational speed of bucket

elevator is decreases gradually and the belt length is increases. The number of bucket remains

almost constant but the diameter of shaft slowly increases (Refer figure 5.2).

Figure 5.2: Variation based on pulley diameter

200 250 300 400 500

Roatational speed (rpm) 305.58 244.46 203.72 152.79 122.23

Belt Length (m) 6.63 6.79 6.94 7.26 7.57

No. of Bucket 17 17 17 18 19

Shaft Diameter (mm) 40 50 60 80 100

0

50

100

150

200

250

300

350

61

Effect of capacity on bucket width, bucket volume, belt width, bucket pitch, motor

power and number of bucket:

Assume lifting height (H) = 1.5 m and pulley diameter (Dp) = 250 mm as constant, than the

effect of capacity on bucket width, bucket volume, belt width, bucket pitch, motor power and

number of bucket is shown in graph (Refer figure 5.3). As the capacity of bucket elevator

increases the bucket width increases and hence the volume of bucket increase as its

dimensions of bucket increases, the belt width also increases. As the capacity increases the

bucket pitch increases but the motor power and number of required buckets decreases.

Figure 5.3: Variation based on capacity

8.63 13.3 21.5 30

Bucket width (mm) 125 160 200 250

Bucket volume (mm3) 10.5 13.3 16.8 21

Belt width (mm) 160 200 250 300

Bucket pitch (mm) 220 320 400 400

Motor Power (kW) 1.14 1.02 1.02 1.24

No. of Bucket 17 12 10 10

0

50

100

150

200

250

300

350

400

450

62

Effect of efficiency on motor power:

Assume lifting height (H) = 1 m, pulley diameter (Dp) = 200 mm capacity (Q) = 13.3 Tonne /

hr as constant, than the effect of efficiency on motor power is shown in graph bellow. As the

efficiency of bucket elevator increases the motor power decrees gradually (Refer figure 5.4).

Figure 5.4: Variation based on efficiency

5.2. RESULT ANALYSIS OF PROTOTYPE MODEL

Observation:

Actual rotational speed of bucket elevator = 320 rpm

1 bucket capacity = 0.95 kg so, for 9 bucket capacity = 8.55 kg

Case: 1

In this case bucket elevator is completely empty means no wheat inside the elevator for

scooping effect on starting and wheat is finished during feeding without checking of scooping

capacity for bucket elevator.

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

Motor Power (Kw) 5.78 2.89 1.93 1.45 1.16 0.96 0.83 0.72 0.64 0.57

0

1

2

3

4

5

6

7

63

Table 5.1: Observation table for 10.00 kg of wheat

Wheat at

inlet for

feeding

(kg)

Wheat inside

the elevator

before starting

of scooping

(kg)

Wheat at

outlet

(kg)

Wheat inside

the elevator

after closing

(kg)

Time

(Second)

Efficiency

(%)

10.00 0.00 4.50 5.50 48.48 45.00

Case: 2

In this case 5.5 kg of wheat is already remaining of case: 1 inside the bucket elevator to see

scooping action from starting of feeding and feeding of wheat is finished within 1 min and

after 1 min for 20.31 second bucket elevator run without feeding of wheat at inlet just to see

the complete scooping action and switch off the power when scooping effect is finished.

Table 5.2: Observation table for 24.75 kg of wheat

Wheat at

inlet for

feeding

(kg)

Wheat inside

the elevator

before starting

of scooping

(kg)

Wheat at

outlet

(kg)

Wheat inside

the elevator

after closing

(kg)

Time

(Second)

Efficiency

(%)

19.25 5.50 18.00 6.50 80.31 72.72

64

Chapter 6: FUTURE SCOPE OF WORK

The velocity analysis can be carried out to understand its effect with change in bucket

angle.

Coding of the C –Program can be refined for its faster and efficient way of its usage

while editing input parameters. Use of fopen, fclose functions i.e. file operations using

C- program will simplify the editing of the input and programming length. This leads

to modular programming for bucket elevator. Existing program coding takes 325 lines

results in difficulty of program modification and may be erroneous results.

The mechanism of bucket elevator is not completed yet due to problem regarding to

belt connection as a joint using Pro/Mechanism. The simulation of the bucket elevator

assembly should be carried out to predict instantaneous velocity and components of

the velocities in the required directions. Moreover, Torque and power calculations can

be obtained using the dynamic simulation considering the gravity effect also. The

obtained results can be compared with the practical one to understand the differences

and subsequent remedial actions. The frictional considerations will be incorporated

during the mechanism simulation along with gravity effect to predict the system

behaviour more realistic.

The effect of clearance between the bucket elevator belt mechanisms along with its

outer casing will be lucrative to analyze for further improvement of its performance.

The throttle plate arrangement for the prototype outlet will be more suitable for the

existing configuration.

The take-up system of the bucket elevators is equipped with additional dust-tight seals

between the casing and the guide of the idle shaft belt bucket elevators realised for

heavy duty application are equipped with a self aligning system which ensure the safe

parallel guidance of the pulley.

An idler mechanism should be also provided for tightening belt during running of

bucket elevator.

65

Chapter 7: CONCLUSION

1. This project was designed to study the design of bucket elevator also enhance the

manufacturing idea about the processes and fabrication of the equipment.

2. Through this experience, we found the chance to apply our knowledge of previous

courses like machine design, Kinematics of machinery, Product Design and Value

Engineering.

3. The designed bucket elevator works having certain limitations.

4. When designing the system, we should make sure the material is cost effective,

and durable. In the meantime, it should also be available in the market.

5. Dimensions should be realistic.

xi

APPENDIX: A

PROGRAM:

/* Program about Bucket Elevator Design */

#include<stdio.h>

#include<conio.h>

void main()

{

clrscr();

intNp, Dp, B, Bb, tb, b, h1, d, yes, no, Shaft_load, Bearing_No, Bearing_bore_diameter,

Bearing_outside_diameter, Permissible_rpm_for_Grease_lubrication, Permissible_rpm_for_Oil_lubrication, rh;

float H, Density, Bp, Q, a, ratio, v, rp, N,n,f, hp, V, mrb, qrb, mb, q0, T3, T4, k=10, i, W, Efficiency, P, t, L, T,

h2, C0, C, w, h, Te;

printf("Lifting Height(H) in m = \n");

scanf("%f", &H);

printf("Wheat Density in Tonne/m3 = \n");

scanf("%f", &Density);

printf("No of Belt ply (Np) = \n");

scanf("%d", &Np);

printf("Efficiency = \n");

scanf("%f", &Efficiency);

printf("Want to enter Capacity (Q)? Enter 1 for yes and 0 for no- \n");

scanf("%d",&yes);

{

if(yes)

{

printf("Capacity (Q) in Tonne/hr = \n");

scanf("%f", &Q);

a=Q/(3.60*3.2*Density*0.75);

{

if(1.1<=a<=1.3)

{

printf("ratio (i0/tb) in m-1 = 1.3 \n");

ratio = 1.3;

}

else if(1.4<=a<=2.0)

{


ratio = 2.0;

xii

}

else if(2.1<=a<=3.24)

{


ratio = 3.24;

}

else if(3.25<=a<=5.0)

{


ratio = 5.0;

}

else if(5.1<=a<=8.0)

{


ratio = 8.0;

}

else if(8.1<=a<=12.6)

{


ratio = 12.6;

}

else

printf("out of range.");

}

}

else

{

printf("Enter value of ratio (i0/tb)- (1.3, 2.0, 3.24, 5.0, 8.0, 12.6) in m-1 = \n");

scanf("%f", &ratio);

Q=(ratio*3.60*3.2*Density*0.75);

printf("Capacity (Q) in Tonne/hr = %f \n", Q);

}

}

printf("Want to enter Pulley diameter (Dp) or Want to use equation Dp=125*Np? Enter 1 for yes and 0 for no-

\n");

scanf("%d",&yes);

{

if(yes)

{

xiii

printf("Pulley diameter (Dp) in mm = \n");

scanf("%d", &Dp);

}

else

{

Dp=125*Np;

printf("Pulley diameter (Dp) in mm = %d \n", Dp);

}

}

rp=(float)Dp/(2*1000);

printf("Pulley radius (rp) in m = %f \n", rp);

N=(float)60*3.2*1000/(3.14*Dp);

printf("Belt velocity (v) in m/s = 3.2 \nRotation speed of prlley (N) in rpm = %f \n", N);

hp=(float)9.81*Q*Q/(3.14*3.14*N*N);

printf("Pole Distance (hp) in m = %f \n", hp);

{

if(hp<rp)

{

printf("Unloading of bucket centrifugally is possible. \n");

{

if(ratio==1.3)

{

printf("Bucket width (B) in mm = 125 \nBelt width (Bb) in mm = 160 \nBucket pitch (tb) in mm = 220 \n");

B=125;

Bb=160;

tb=220;

}

else if(ratio==2.0)

{


B=160;

Bb=200;

tb=320;

}

else if(ratio==3.24)

{


B=200;

Bb=250;

xiv

tb=400;

}

else if(ratio==5.0)

{


B=250;

Bb=300;

tb=400;

}

else if(ratio==8.0)

{


B=320;

Bb=370;

tb=500;

}

}

V=(float)21*B/250;

printf("Bucket volume in mm3 = %f \n", V);

mrb=2.4*Np/4;

qrb=9.81*mrb;

mb=3.38*B/250;

q0=qrb+(9.81*mb*1000/tb);

T4=(float)q0*H;

T3=(float)3.00*T4;

printf("Tension T3 in N =%f \nTension T4 in N = %f \n", T3,T4);

i=(float)k*T3/(Bb*55);

printf("Safety factor k = 10 \nRequired no. of belt plies (i) = %f \n", i);

W=(float)(T3-T4)/1.08;

printf("Pulley Resistance (W) in N = %f \n", W);

P=(float)1.25*W*3.2/(1000*Efficiency);

printf("Motor power (P) in kW = %f \n", P);

Bp=(float)1.25*Bb;

printf("Pulley width (Bp) in mm = %f \n", Bp);

t=(float)(Dp/200)+2;

printf("Rim thickness (t) in mm = %f \n", t);

L=(float)2*H+(3.14*Dp/1000);

printf("Belt length (L) in m = %f \n", L);

T=(float)(T3-T4)*Dp/2;

xv

printf("Belt Tension (T) in Nm = %f \n", T);

f=(float)T3/Bb;

printf("Permissible Tension (f) in belt per mm width in N/mm = %f \n",f);

{

if(108<=B<=120)

printf("Projection of bucket (b) in mm =79 \nDepth of Bucket (h1) in mm = 79 \nh2 in mm = 47.08 \n");

else if(121<=B<=180)


else if(181<=B<=235)


else if(236<=B<=320)

printf("Projection of bucket (b) in mm =156\n Depth of Bucket (h1) in mm = 156 \nh2 in mm = 92.98 \n");

else

printf("out of range. \n");

}

n=(float)L*1000/tb;

printf("N0. of Bucket (n) = %f \n", n);

if(Bb==160 &&Dp==200)

{

printf("Shaft diameter (d) in mm = 25 \nShaft_load in kN = 5 \nBearing_No = 6005 \nBearing_bore_diameter in

mm = 25 \nBearing_outside_diameter in mm = 47 \nBearing_width in mm = 12 \nBearing static load (C0) in kN

= 6.55 \nBearing Dynamic load (C) in kN = 11.20 \nPermissible_rpm_for_Grease_lubrication = 15000

\nPermissible_rpm_for_Oil_lubrication = 18000 \n");

d=25;

}

else if(Bb==200 &&Dp==200)

{





d=30;

}

else if(Bb==250 &&Dp==200)

{





xvi

d=35;

}

else if(Bb==160 &&Dp==250)

{





d=35;

}

else if(Bb==300 &&Dp==200)

{

printf("Shaft diameter (d) in mm = 40\n Shaft_load in kN = 8 \nBearing_No = 6008 \nBearing_bore_diameter in




d=40;

}

else if(Bb==200 &&Dp==250)

{





d=40;

}

else if(Bb==160 &&Dp==300)

{





d=40;

}

else if(Bb==250 &&Dp==250)

{



xvii



d=45;

}

else if(Bb==200 &&Dp==300)

{





d=45;

}

else if(Bb==160 &&Dp==350)

{





d=45;

}

else if(Bb==300 &&Dp==250)

{

printf("Shaft diameter (d) in mm = 50 \nShaft_load in kN = 10 \nBearing_No = 6010 \nBearing_bore_diameter

in mm = 50 \nBearing_outside_diameter in mm = 80 \nBearing_width in mm = 16 \nBearing static load (C0) in

kN = 16.00 \nBearing Dynamic load (C) in kN = 21.60 \nPermissible_rpm_for_Grease_lubrication = 8500


d=50;

}

else if(Bb==160 &&Dp==400)

{





d=50;

}

else if(Bb==370 &&Dp==200)

{

xviii





d=55;

}

else if(Bb==250 &&Dp==300)

{





d=55;

}

else if(Bb==200 &&Dp==350)

{





d=55;

}

else if(Bb==300 &&Dp==300)

{





d=60;

}

else if(Bb==200 &&Dp==400)

{





d=60;

}

else if(Bb==160 &&Dp==400)

xix

{





d=60;

}

else if(Bb==370 &&Dp==250)

{





d=65;

}

else if(Bb==250 &&Dp==350)

{





d=65;

}

else if(Bb==160 &&Dp==500)

{





d=65;

}

else if(Bb==300 &&Dp==350)

{





d=70;

}

xx

else if(Bb==200 &&Dp==450)

{





d=70;

}

else if(Bb==370 &&Dp==300)

{





d=75;

}

else if(Bb==250 &&Dp==400)

{





d=75;

}

else if(Bb==200 &&Dp==500)

{





d=75;

}

else if(Bb==300 &&Dp==400)

{





d=80;

xxi

}

else if(Bb==250 &&Dp==450)

{

printf("Shaft diameter (d) in mm = 85 \nShaft_load in kN = 17 \nBearing_No = 6017 \n");

d=85;

}

else if(Bb==370 &&Dp==350)

{


d=90;

}

else if(Bb==300 &&Dp==450)

{


d=90;

}

else if(Bb==250 &&Dp==500)

{


d=90;

}

else if(Bb==300 &&Dp==500)

{


d=100;

}

else

printf("Out of range. \n");

rh=d;

printf("Radius of hub (rh) in mm = %d \n", rh);

w=(float)d/4;

printf("Key width (w) in mm = %f \n", w);

h=(float)2*w/3;

printf("Key height (h) in mm = %f \n", h);

Te=(float)52.8*3.14*d*d*d/16/1000000;

printf("Equivalent torque acting on shaft (Te) in kNm = %f \n", Te);

}

else

{

xxii

printf("Unloading of bucket centrifugally is not possible. \n");

}

}

getch();

}

SAMPLE COMPUTATION:

1. For Bucket Elevator Design:

Input:

Lifting Height(H) in m = 3

Wheat Density in Tonne/m3 = 0.768

No of Belt ply (Np) = 4

Efficiency = 0.85

Want to enter Capacity (Q)? Enter 1 for yes and 0 for no - 1

Capacity (Q) in Tonne/hr = 30

Want to enter Pulley diameter (Dp)? or Want to use equation Dp=125*Np? Enter 1 for yes and 0 for no – 0

Output:

Ratio (i0/tb) in m-1 = 5.0

Pulley diameter (Dp) in mm = 500

Pulley radius (rp) in m = 0.250000

Belt velocity (v) in m/s = 3.2

Rotation speed of pulley (N) in rpm = 122.292992

Pole Distance (hp) in m = 0.073231

Unloading of bucket centrifugally is possible.

Bucket width (B) in mm = 250

Belt width (Bb) in mm = 300

Bucket pitch (tb) in mm = 400

Bucket volume in mm3 = 21.000000

Tension T3 in N = 957.946533

Tension T4 in N = 319.315521

xxiii


Required no. of belt plies (i) = 0.580574

Pulley Resistance (W) in N = 591.325012

Motor power (P) in kW = 2.782706

Pulley width (Bp) in mm = 375.000000

Rim thickness (t) in mm = 4.000000

Belt length (L) in m = 7.570000

Belt Tension (T) in Nm = 159657.750000

Permissible Tension (f) in belt per mm width in N/mm = 3.193155

Projection of bucket (b) in mm = 156

Depth of Bucket (h1) in mm = 156

H2 in mm = 92.98

No. of Bucket (n) = 18.925001

Shaft diameter (d) in mm = 100

Shaft_load in kN = 22

Bearing_No = 6020

Radius of hub (rh) in mm = 100

Key width (w) in mm = 25.000000

Key height (h) in mm = 16.666666

Equivalent torque acting on shaft (Te) in KNm = 10.362000

2. For Bucket Elevator Prototype:

Inputs:

Lifting Height(H) in m = 1

Wheat Density in Tonne/m3 = 0.768

No of Belt ply (Np) = 2

Efficiency = 0.85

Want to enter Capacity (Q)? Enter 1 for yes and 0 for no - 0

Enter value of ratio (io/tb)- (1.3, 2.0, 3.24, 5.0, 8.0, 12.6) in m-1 = 2.0

Want to enter Pulley diameter (Dp)? or Want to use equation Dp=125*Np? Enter 1 for yes and 0 for no - 1

Pulley diameter (Dp) in mm = 200

Output:

Capacity (Q) in Tonne/hr = 13.271040

Pulley radius (rp) in m = 0.100000

Belt velocity (v) in m/s = 3.2

Rotation speed of pulley (N) in rpm = 305.732483

Pole Distance (hp) in m = 0.001875

xxiv

Unloading of bucket centrifugally is possible.

Bucket width (B) in mm = 160

Belt width (Bb) in mm = 200

Bucket pitch (tb) in mm = 320

Bucket volume in mm3 = 13.440000

Tension T3 in N = 234.262802

Tension T4 in N = 78.087601


Required no. of belt plies (i) = 0.212966

Pulley Resistance (W) in N = 144.606674

Motor power (P) in kW = 0.680502

Pulley width (Bp) in mm = 250.000000

Rim thickness (t) in mm = 3.000000

Belt length (L) in m = 2.628000

Belt Tension (T) in Nm = 15.617

Permissible Tension (f) in belt per mm width in N/mm = 1.171314

Projection of bucket (b) in mm = 105

Depth of Bucket (h1) in mm = 105

H2 in mm = 47.08

No. of Bucket (n) = 8.212500

Shaft diameter (d) in mm = 30

Shaft_load in kN = 6

Bearing_No = 6006

Bearing_bore_diameter in mm = 30

Bearing_outside_diameter in mm = 55

Bearing_width in mm = 13

Bearing static load (C0) in kN = 8.30

Bearing Dynamic load © in kN = 13.30

Permissible_rpm_for_Grease_lubrication = 12000

Permissible_rpm_for_Oil_lubrication = 15000

Radius of hub (rh) in mm = 30

Key width (w) in mm = 7.500000

Key height (h) in mm = 5.000000

Equivalent torque acting on shaft (Te) in KNm = 0.279774

xxv

BIBLIOGRAPHY

1. Spivakovsy, A.O. and Dyachkov, V.K. (1985), Conveying Machine, MIR Publication,

Forth Edition.

2. Balagurusamy, E. (1998), Programming in ANSI C, Tata McGraw-Hill Publishing

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Design and Model of Bucket Elevator

Engineering

Transcript of Design and Model of Bucket Elevator