RESEARCH AND DESIGN OF MATERIAL SUPPLIES FOR CONSTRUCTION MIXING PLANT

In all mechanical machinery there is mechanical movement of machine parts. People need energy to create that movements. One of the most common forms of energy today is electricity. In the history of invention, people have found that the electric motor is the most optimal, it has a much greater efficiency than the other type of motor. In industrial production to improve productivity and economic efficiency as well as feasibility, electric motors are manufactured with power and rotational speed as a specific value established in standard tables. Meanwhile, mechanical machines need arbitrary power without any standard. Therefore, electric motors cannot transmit power directly to moving systems, but must go through a conversion device, which is a reducer. The gear box is a directcoupled, constantratio transmission device used to reduce angular velocity and increase torque. Thus, it is seen that a moving machinery system needs to have components such as: Motor, transmission, reducer and load system. Such a system is called a mechanical drive system. Conveyor belt drive system is a system widely used in factories, enterprises, construction sites, etc., characterized by high conveying capacity, diversified transportation types. Bulk materials or finished articles can be transported, to meet each production lines requirements in terms of distribution form and transport technology requirements. Depending on the production conditions to decide to use a conveyor or a combination of multiple conveyors with other conveyor equipment to realize continuity and automation in production, improve productivity and reduce labor intensity. The investment cost of manufacturing conveyor belts is not very large on the basis of simple structure and does not use too many expensive specialized materials. Compared with other transport equipment used in the mining industry, the cost per tonkm is much cheaper than that of cars and other means of transport except for railways. Conveyor belt is a continuous transport device, working thanks to the frictional force between the belt surface and the drum, a conveyor driving station is usually composed of three main parts: Motor transmission and torque, gear box and conveyor.

HO CHI MINH CITY NATIONAL UNIVERSITY

HO CHI MINH CITY UNIVERSITY OF TECHNOLOGY

No:

1 Title of thesis:

DESIGN OF GARBAGE COLLECTOR ON THE

BEACH (Thiết Kế Máy Gom Rác Bờ Biển)

2 Objectives:

- Learn about the process of garbage collection on the sandy shore

and the solar energy system

- Suggest and choose the optimal method for machine design

- Doing calculations to design mechanism of waste collection and

remove unwanted materials from beach

- Doing calculations to design the solar energy system

- Making suggestions, and notes for operation – repair – maintenance process

- Estimated drawings: 07, include:

+ 1 drawing A0, about: General drawing

+ 1 drawing A0, about: Drawing of options diagram

+ 1 drawing A0, about: Drawing of principle and kinematic diagram+ 1 drawing A0, about: Assembly drawing of vibrating screener+ 1 drawing A0, about: Assembly drawing of screening frame

+ 1 drawing A0, about: Assembly drawing of pulling unit

+ 1 drawing A0, about: Drawing of motor starter cuircuit

3 Date of making assignment: 30 / 01 / 2023

4 Date of finishing assignment: 12 / 05 / 2023

5 Full name of instructor: Thân Trọng Khánh Đạt

Guidelines contents: 100% Contents and requirements of CP are approved by Department

PART FOR FACULTY, DEPARTMENT

Engineering Department, I can realize the importance of the

knowledge that I have

received from my teachers

I would like to sincerely thank the assistance of lecturers in the department of mechanical

engineering, and especially thanks to the instruction of Mr NguyenHai Dang, who

accepted to instruct and helped me a lot in this stage Throughout the process of learning,

all of the advice I have received has not just helped me improve and advance my

specialist knowledge but also provided opportunities for me to think and accumulate

experiences for my future job

In addition, I would like to thank all of the lecturers at Ho Chi Minh

City University of

Technology who are ready to impart knowledge and support me throughout the whole

period I have studied here

Moreover, I also want to send special thanks to my family and my friends, especially my father, my brother Nguyen Minh Long, who are always side by side to support me and even motivate me to overcome the difficulties

These motivations pushed me and made me try harder to finish the thesis Honestly, I

cannot complete my project without these motivations

Finally, I wish all of the teachers good health and that they will always be the pioneers

who guide the next generations on the path of study and research

at this university

Once again, thank you very much!

Ho Chi Minh city, 12/05/2023

Student: Nguyễn Nhật Tiến

TABLE OF CONTENTS PREFACE

CONTENTS

LIST OF FIGURES

LIST OF TABLES

Chapter I

INTRODUCTION TO BELT CONVEYOR 8

1.1 Introduction of conveyor drive system in concrete batching plant 8

1.2 Components of concrete 8

1.2.1 Cement 8

1.2.2 Sand 8

1.2.3 Crushed stone 8

1.2.4 Water 8

1.2.5 Additives 8

1.2.6 Example of concrete mix ratio 9

Chapter II

OVERVIEW ABOUT TECHNOLOGY SOLUTIONS 10

2.1 Methods of transporting bulk materials 10

2.1.1 Conveyor 11

2.1.2 Bucket Loading 11

2.1.3 Screw conveyor 13

2.2 General structure of the conveyor system 16

2.3 Material quantification method 16

2.3.1 Loadcell weighing system 11

2.3.2 Working principle 11

2.3.3 The method to install the sensor into the system 11

Chapter III

BELT CONVEYOR DESIGN PROCESS 18

3.1 Design goals 19

3.1.1 Determine the minimum width (B) of the conveyor 19

3.1.2 Determine the height of the conveyor 19

3.1.3 Determine the speed of the conveyor 19

3.1.4 Calculation of conveyor transmission power 21

3.1.5 Determine the height of the conveyor 23

3.1.6 Conveyor belt tension 23

3.1.7 Calculation of ribbon selection 25

3.1.8 Conveyor system structure 25

3.1.9 Calculation of the tensioning mechanism 27

3.2 Electric motor selection 32

3.2.1 Select engine type 32

3.2.2 Select engine power 32

3.2.3 Select number of synchronous revolutions of the motor 33

3.2.4 Calculate shaft parameters and choose motor 34

3.3 Calculate and design roller chain transmission 35

3.3.1 Select chain type 35

3.3.2 Determination of chain transmission parameter 35

3.3.3 Check the roller chain durability 35

3.3.4 Determination of sprocket parameters 35

Chapter IV

TESTING STRESS AND ROLLER MACHINING PROCESS 39

4.1 Pulley axis 39

4.1.1 Choose material for the shaft 39

4.1.2 Shaft preliminary calculation 39

4.1.3 Approximate value on shaft and moment calculation 40

4.1.4 Shaft test for fatigue strength 44

4.1.5 Shaft test for static strength 50

4.2 Carrier roller shaft……… ………

……… 51

4.2.1 Calculate the force acting between 2 rows of rollers 39

4.2.2 Shaft preliminary calculation 39

4.2.3 Approximate value on shaft and moment calculation 39

4.2.4 Shaft test for static strength 39

4.3 Technological process of roller ………

……… 51

Chapter V …

………

OPERATE AND MAINTENANCE THE MACHINE 39

5.1 Install the machine 39

5.2 Operate the machine 39

5.3 Maintenance the machine 39

Chapter VI ………

CONCLUSION AND FUTURE DEVELOPMENTS………

39 6.1 Conclusion 39

6.2 Remaining problems 39

6.3 Future developments 39

Reference 53

LIST OF FIGURES

Figure 1.1 Belt conveyor for transporting aggregates 8

Figure 2.1 Belt conveyor 10

Figure 2.2 Bucket construction structure 11

Figure 2.3 Horizontal screw conveyor 11

Figure 2.4 Supporting structure of a Belt conveyor system 15

Figure 2.5 Conveyor idler with trough angle 18

Figure 2.6 Flat rollers and chute rollers 20

Figure 2.7 Surcharge angle 22

Figure 2.8 Screw type take-up system 25

Figure 2.9 Vertical gravity type take-up system 27

Figure 2.10 Horizontal gravity type take-up system 30

Figure 2.11 Power system type take-up system 31

Figure 2.12 Load cell weighing system 32

Figure 2.13 General structure of electronic weighing device 34

Figure 2.14 Working description of load cell 35

Figure 2.15 Simulation of installation of load cells 36

Figure 3.1 Actual slope angle of conveyor 37

Figure 3.2 Cross section of conveyor belt 38

Figure 3.3 The force components on the conveyor 41

Figure 3.4 Illustration of different types of pulleys 46

Figure 3.5 Classification of pulley with specific range of application 48

Figure 3.6 Cylindrical pulley texture 53

Figure 3.7 Transition distance b between the last roller and the pulley 55

Figure 3.8 Diagram of force acting on the tensioning mechanism 58

Figure 3.9 Working load diagram 59

Figure 3.10 GM-D/DP Series Three-phase Motor 66

Figure 3.11 GM-D/DP Series Motor Catalogue 75

Figure 3.12 Technical drawing of chosen motor 76

Figure 4.1 Torque diagram and structure of the guide shaft 80

Figure 4.2 Key joint 82

Figure 4.3 SKF Spherical roller bearing with lubrication features 85

LIST OF TABLES

Table 1.1 Mixing concrete grade and ratio of materials 8

Table 3.1 Belt conveyor initial data 10

Table 3.2 Coefficient by Angle of Incline 11

Table 3.3 Density of material 13

Table 3.4 Angle of Incline of Belt conveyor with materials 15

Table 3.5 Coefficient of Sectional Area “K” 18

Table 3.6 Maximum Belt speed (in unit: m/min) 20

Table 3.7 Friction Coefficient of Idlers “f” and adjusted horizontal length “l0” 22

Table 3.8 Multi-ply Fabric belt Safety factor values “SFz” 25

Table 3.9 Pulley Diameter corresponding to groups 27

Table 3.10 Pulley Factor “K” with Fabric type 30

Table 3.11 Minimum pulley diameter for Nylon fabric Belt 30

Table 3.12 Chain drive parameters 30

Table 4.1 Dimensions of the keyway and keyway section (TCVN 4214-86) 30

Table 4.2 Dimensions of SKF spherical roller

bearing……… 30

Table 5.1 Maintenance schedule for machine 30

In industrial production to improve productivity and economic efficiency aswell as feasibility, electric motors are manufactured with power and rotationalspeed as a specific value established in standard tables Meanwhile, mechanicalmachines need arbitrary power without any standard Therefore, electric motorscannot transmit power directly to moving systems, but must go through aconversion device, which is a reducer The gear box is a direct-coupled, constant-ratio transmission device used to reduce angular velocity and increase torque.

Thus, it is seen that a moving machinery system needs to have componentssuch as: Motor, transmission, reducer and load system Such a system is called amechanical drive system

Conveyor belt drive system is a system widely used in factories, enterprises,construction sites, etc., characterized by high conveying capacity, diversifiedtransportation types Bulk materials or finished articles can be transported, to meeteach production line's requirements in terms of distribution form and transporttechnology requirements Depending on the production conditions to decide to use aconveyor or a combination of multiple conveyors with other conveyor equipment torealize continuity and automation in production, improve productivity and reducelabor intensity

The investment cost of manufacturing conveyor belts is not very large on thebasis of simple structure and does not use too many expensive specialized materials.Compared with other transport equipment used in the mining industry, the cost perton/km is much cheaper than that of cars and other means of transport except forrailways

Conveyor belt is a continuous transport device, working thanks to thefrictional force between the belt surface and the drum, a conveyor driving station isusually composed of three main parts: Motor transmission and torque, gear box andconveyor

Conveyor belt is a machine that transports bulk material horizontally byplacing the material on a moving belt The material will be carried from one end ofthe tape to the other and removed at the end of the tape

Conveyor belt consists of a rubber or cloth or metal belt attached to twopulleys at both ends Underneath the tape are support rollers that prevent the tapefrom sagging under load One of the two pulleys is connected to the electric motorand the other is a belt pulley All mounted on a sturdy steel frame When the drivepulley rotates, the belt moves along

Figure 1.1 Belt conveyor for transporting aggregates

1.2 Components of concrete

1.2.1 Cement

The choice of cement is especially important in the production ofconcrete, there are many different types of cement, the higher the cement

grade, the better the adhesion ability and increase the quality of concretedesign The cost of high-grade cement is very large Therefore, whendesigning concrete, it is necessary to ensure that the quality meets the technicalrequirements and solve the economic problem well.

1.2.2 Sand

Sand used in concrete production can be natural sand or artificial sand, thesize of sand is from 0.4 to 5 mm The quality of sand depends on mineralcomposition, impurity composition, grain composition In the composition ofconcrete, sand accounts for about 29%

1.2.3 Crushed stone

Crushed stone has many types depending on the size of the stone, sodepending on the size of the concrete, we choose the appropriate stone size Inthe concrete, crushed concrete accounts for about 52%

This type of surfactant, although used in small amounts, has the ability

to significantly improve the properties of the concrete mix and enhance manyother properties of the concrete

+ Fast solidifying additive:

This type of fast curing admixture has the ability to shorten the curingprocess of concrete under natural conditions as well as increase concrete strength.Currently, in concrete production technology, people also use multifunctionaladmixtures

1.2.6 Example of concrete mix ratio

Calculate for 1 m3 of concrete

Table 1.1: Mixing concrete grade and ratio of materials

2.1.1 Belt Conveyor

Conveyor belt is a machine that transports bulk material horizontally byplacing the material on a moving belt The material will be carried from one end ofthe tape to the other and removed at the end of the tape

Conveyor belt consists of a rubber or cloth or metal belt attached to twopulleys at both ends Underneath the tape are support rollers that prevent the tapefrom sagging under load One of the two pulleys is connected to the electric motorand the other is a belt pulley All mounted on a sturdy steel frame When the drivepulley rotates, the belt moves along

Figure 2.1 Belt conveyor

Advantages

- High safety, simple structure, durable, quiet working

- Capable of transporting bulk and single materials in horizontal, inclinedand a combination of both.

- No damage to the material since the material has no relative motion withrespect to the ice

- Investment and manufacturing capital is not large; can be automated

- Simple operation, easy maintenance

- Low energy consumption

- Large transport capacity can reach 500 tons/h

Disadvantages:

- Conveyor belt has a low allowable slope, usually from 16-24° depending

on the material;

- Curve transport is not possible;

- Unable to transport flexible, sticky materials

- Shipping speed is not high

2.1.2 Bucket Loading

To transport bulk materials (powder, granules, small lumps) vertically or at anincline over 50°, a bucket is used

Figure 2.2 Bucket construction structure

Advantages:

- Lifting height can be achieved H = 50÷55 m

- Large transport capacity can reach 500 tons/h

- Transport direction is vertical Transport inclined with fuel angle> 50°

- Stable operation, high reliability, easy maintenance, long service life

- If the conveying material is large, it will cause impact and noise

- Easily overloaded if the supply is uneven, so it needs to be refilled regularly

- Height is limited due to kinematic structure

- Can not be transported horizontally When transporting, the right angle ofinclination is > 50°

- Can not be transported horizontally When transporting, the right angle ofinclination is > 50°

Scope of use

- Bucket is used to transport materials in the form of coal bran or bulk materialssuch as coal, cement, ore, iron, steel, clay used in industry In addition, bucketsare also used to transport agricultural products such as rice, corn, etc

- Bucket mechanism used to transport a large volume of materials at differentheights vertically or horizontally, into a dust-free pile

2.1.3 Screw conveyor

It is a kind of continuous conveying machine without traction part

Figure 2.3 Horizontal screw conveyor

Screw conveyors are used to transport materials with a length of up to 40 m,mainly used to transport loose and fine granular materials such as cement, gravel,sand, crushed stone and wet mixtures such as concrete and mortar Used as aforced feeding mechanism, in concrete batching plants, mixing machines forasphalt

Transport capacity can reach 2030 m3/h, large-sized screws can reach100m3/h

The size of the outer diameter of the screw is usually standardized andspecified in a range of sizes: 150, 200, 250, 30, 400; 500; 600mm Usually placedvertically, inclined or horizontally

Conveying materials by screw conveyor has many advantages

- Moving materials in sealed boxes, receiving and unloading at any position, sothere is no loss, spillage, safety

- Simple structure, cheap, can be transported and mixed

- Small installation area, easy to operate and convenient.

- However, screw conveyor also has some disadvantages such as

- Due to the gap between the trough and the screw, it is easy to crush part of thematerial

- Because of the large friction and mainly sliding friction, it quickly wears out thespiral blades and the chute It is also for this reason that the energy loss is large

- Only loose materials can be transported, not materials with large adhesion orfibrous properties due to sticking to the shaft causing jamming

Scope of use

Due to certain advantages and compatibility with certain materials andtransport technologies, screw conveyors are used in the construction industry andthe chemical and food industries

2.2 General structure of the conveyor system

Figure 2.4 Supporting structure of a Belt conveyor system

- Troughing carrying idler:

Trough angle, the conveyor belt can be arranged horizontally (Flat belt), similar

to the flat belt transmission However, people often use more inclined rollers(troughing idlers) to bend the conveyor belt into a concave trough, in order totransport items more stably

Figure 2.5 Conveyor idler with trough angle

Figure 2.6 Flat rollers and chute rollers

Surcharge angle

When items are piled, the angle at the top of the pile is called the Surchargeangle The roof angle when transporting is smaller than when standing still

Figure 2.7 Surcharge angle

Belt take-up system

The belt take-up mechanism is responsible for creating the necessary tension for thetape, ensuring the tape adheres to the guide and reducing the sag of the tape alongthe length There are two types of belt tensioners commonly used: screw tensionersand counterweight tensioners

Because the conveyor belt is not large in length Select a mechanism that uses aforced screw-nut to stretch the tape When the nut is positioned on the frame, turnthe screw and push the drum shaft a distance L to stretch the tape This type ofstructure is simple, sturdy, and has high reliability The working stroke of the screwdepends on the conveyor length (usually about 1-1.5% of the conveyor length butnot > 400 mm)

There are four types of commonly used belt tensioners: Screw type, Verticalgravity type, Horizontal gravity type and Power system type

a Screw type

Simple structure, low cost, small frame size and weight This type is oftenused for conveyor belts with not very large lengths and in the process of stretchingthe belt many times requiring repeated tensioning The working stroke of the screwdepends on the conveyor length (usually about 1-1.5% of the conveyor length butnot >400mm)

Figure 2.8 Screw type take-up system

b Vertical gravity type

The vertical gravity take-up can be arranged by using the space position ofconveyor corridor The extension of conveyor belt can be automaticallycompensated by gravity with the change of tension Each 15kg iron block isinstalled in the heavy weight box to adjust the tension The heavy weight tensiondevice is arranged in the lower space or tail space of the belt conveyor, withcompact layout It is suitable for the belt conveyor with a length of more than 50m,which is widely used in the workshop or the belt conveyor with a small length Thistype of tensioning device shall be preferred.

Figure 2.9 Vertical gravity type take-up system

c Horizontal gravity type

This type of take-up is similar to the gravity take-up, but instead of the assemblysituated below the belt, it is positioned vertically behind the tail pulley This makes

it particularly useful in situations where the conveyor is positioned on a grade thateliminates any additional space under the conveyor

Since the horizontal take-up does not fall below the conveyor, a system of pulleysand cables is used to tension the belt with a weight box The cabling attaches to thetail pulley, which rides on a carriage, allowing it to be moved in and out of place

Figure 2.10 Horizontal gravity type take-up system

d Power system type

This type of take-up mechanism is a quite complicated method, including motor fortake-up, Breaking mechanism, Eddy current coupling, Speed detecting generator,Tension sensor (Magnecell), Speed controller that connect together This method isalso for other type of Belt conveyor rarely for bulk handling, requiring sufficienttechnological devices and bugget for

company

Figure 2.11 Power system type take-up system

Conclusion: With the conveyor system, it is necessary to design a relatively

large structure, so to ensure the most optimal tensioning, we choose a Srew typetake-up mechanism for an effectiveness and cost-saving possibility Also, it ispopularly manufactured among these four alternatives

2.3 Material quantification method:

2.3.1 Loadcell weighing system:

Figure 2.12: Load cell weighing system

Today, electronic weighing devices are widely used in many fields:bench scales, floor scales, car scales, hanging scales, analytical balances,pocket scales, gold scales, counting scales, aquatic scales, hopper scales,weighing scales bagging, drum weighing, technological weighing inproduction lines, concrete batching plants from 20kg to 100 tons

Weighing weight: analytical balance capable of weighing from 52g

to 210g with accuracy from 0.0001g to 0.00001g, technical weighing from100g to 20kg; industrial scales from 30kg to 120 tons; car weighing scale

A similar load cell weighing system consists of one or several load cellsconnected in parallel through a junction box

Each load cell loads an independent output, typically 1 to 3 mV/V Thecombined output is aggregated based on the output of each load cell

Measuring devices or display units amplify the electrical signal, via ADCconverter, microprocessor with built-in software that performs calibrationcalculations and outputs the readings to a modern display both allowscommunication with other external devices such as a computer or printer.

Figure 2.13: General structure of electronic weighing device

- Weight (gravity) sensor, also known as Loadcell: is a device that converts a physical quantity (mass, force, etc.) into an electrical quantity

- Amplifier: It is responsible for receiving the signal from the

Loadcell to amplify the signal up to put into the processing unit

- Processing unit: The central processing unit receives the signal for processing and outputs it to the display unit

- Display part: Displays the measured mass

2.3.2 Working principle

A voltage is supplied to the load cell input (2 corners (1) and (4) of the Wheatstoneresistor bridge) and the output signal voltage is measured between the other twoangles

Figure 2.14: Working description of load cell 2.3.3 The method to install the sensor into the system

Figure 2.15: Simulation of installation of load cells

Because the loadcell is used to weigh a material hopper consisting of 4 legs, the weight is from top to bottom Therefore, it is recommended to use a flexural load cell installed on the 4 legs of the weighing hopper At this time, the control system will receive the signal of 4 load cells, using the summation circuit to give the weight

of the entire hopper and the material on the hopper Subtracting the mass of the previously designed hopper, we get the mass of the material

CHAPTER III BELT CONVEYOR DESIGN PROCESS 3.1 Design goals

Currently, many countries in the world with developed industries havedesigned and manufactured high-yield conveyor belts for their own use or export

We have had to import many types of conveyor belts from many countries around

the world to use in the mining industry such as the Soviet Union, Poland, China Therefore, the design and manufacture of domestic conveyors is a necessity set.

The manufactured conveyor must ensure the input parameters, economic andtechnical criteria as well as the ability to work in a certain time

Conveyor design objectives in the project: Calculation and design ofmechanical systems for conveyors to transport sand and rock

Design the drive system to transport sand with capacity 150 tons/h, length10m, with inclination angle 20°

* Specific content:

- Conveyor design;

- Calculation to choose the standard reducer;

- Design of drive shaft and drum;

- Design a system of ground bolts for the drive drum support assembly

Table 3.1: Belt conveyor initial data

Shipping length

3.1.1 Determine the minimum width (B) of the conveyor

The width of the conveyor belt depends on the traffic flow and the size of theitem (or particle size) transported on the conveyor The larger the item size, the larger the tape width should be

B= 1

18( √S V γ Q )= 1

18( √0.81 x 1.25 x 1.44100 )=0.46(mm)

In which:

S = 0.81 là hệ số góc nghiêng của băng tải

V = 1,25 là tốc độ vận chuyển của băng (m/s)

γ = 1,44 là trọng lượng riêng của vật liệu vận chuyển (tấn/m3)

Table 3.2: Coefficient by Angle of Incline

Table 3.3: Density of material

With the type of material to be transported is sand, see Table in [1], we choose a conveyor with a width of B = 600 (mm)

Determine the rubber sheet tape thickness:

δb = δ.i + δ1 + δ2

In which:

δ = 1.25, the fabric core thickness (mm)

i = 3, the number of core layer

δ1 = 1.5, the material contact rubber layer thickness (mm)

δ2 = 1, the material not contact rubber layer thickness (mm)

So δb = 6.25 (mm)

3.1.2 Determine the height of the conveyor

Figure 3.1: Actual slope angle of conveyor

According to the beginning of the article, the length of the tape is L=10m, the transport inclination angle is βt=20° (suitable angle for transporting sand), so wehave the lifting height of the conveyor belt:

H=tgB L=tg20°.10 = 3.63 (m)

Table 3.4: Angle of Incline of Belt conveyor with materials

3.1.3 Determine the speed v of the conveyor belt

Conveyor speed should be limited depending on the capacity of the belt, the width of the belt and the characteristics of the material to be transported

Conveyor speed is usually calculated based on a given required traffic flow The conveyance of a conveyor is usually calculated by the formula:

Qt = 60.A.v..s (ton/h)

So conveyor speed:

v = Qt/60A..s (4.1)

In which:

Qt : Traffic flow (ton/h)

A : Transport line cross-sectional area (m3)

v : Conveyor speed (m/min)

 : Calculated density of the mass of mate (ton/m3)

S : Coefficient of inclination angle

Flow cross-sectional area

Determined by the formula:

Table 3.5: Coefficient of Sectional Area “K”

Figure 3.2 Cross section of conveyor belt

Influence coefficient of conveyor slope

The steeper the conveyor belt, the lower the material flow rate

According to table 7[1], we have the influence coefficient of conveyor slope s

= 0.81

Instead of (2.1), we recheck the conveyor speed:

60 x 1.44 x 0.81 x 0.029= 47.95(m/min)  v = 1,493 (m/s)

According to table [3.5], the maximum speed of the conveyor corresponding

to B = 600 (mm) is: vmax= 240 (m/min) > v

 So velocity satisfies condition

Table 3.6: Maximum Belt speed (in unit: m/min)

3.1.4 Calculation of conveyor transmission power

The capacity to rotate the conveyor roller is calculated according to the formula:

P = P1+P2+P3+Pt (Kw) (4.2)

The components are calculated as follows:

0 1

.( )w.

(2.3) 6120

Wm: Weight of items distributed per unit length of conveyor (Kg/m)v: Belt speed (m/min)

H: Lift height (m)l: Horizontal conveyor length (m)

l0: Adjusted horizontal conveyor length (m)

Qt: Transport capacity (ton/hr)According to Table 8[1] we have: f =0.22; l0=66m

No tripper drive power so we have: Pt = 0 kW

Table 3.7: Friction Coefficient of Idlers “f” and Adjusted horizontal length of

W c: Weight of revolving parts of one set of carrier rollers (kg)

W r: Weight of revolving parts of one set of return rollers (kg)Theo bảng 11[1] ta có: Wc = 8,3 (kg/set) ; Wr = 6,8 (kg/set)

l c: Pitch of carrier roller (m)

l r: Pitch of return roller (m)

Substitute the values into the formula (2.2), (2.3), (2.4), (2.5):

P1 = 0,022(10+66) x 248 x 47,656120 = 3,2488 (kW)

P2 = 0,022(10+66) x 100

367 = 0,455 (kW)

P3 = 3,64 x 100367 = 0,99 (kW)

=> P = 0,805 + 0,455 + 0,99 = 4,6938 (kW)

3.1.6 Conveyor belt tension

Figure 3.3: The force components on the conveyor

In which:

F1, F2 are the tensions on the loaded and unloaded branches, respectively, the relationship between F1, F2 similar to the relationship in the belt drive F1 F e2 

 and F F1 2 F p

e =2,718: Natural logarithmic base

μ: Coefficient of friction between pulley and beltθ: Angle between pulley and belt

According to table 16[1] we have: μ = 0,3

According to table 15[1] we have θ = 1800 = 3,14(rad)

The minimum tension is determined to keep the conveyor belt from slipping

by more than 2% of the distance between the rollers

F4C = 6.25.lc(Wm+W1) (4.8)

F4r = 6,25.lr.W1

(4.9)

In which:

F4c: Minimum tension of carrier side (kg)

F4r: Minimum tension of return side (kg)

Wm: Weight per meter of material transported (kg/m)

W1: Weight per meter of belt (kg/m)

lC: Carrier idler pitch (m)

lr: Return idler pitch (m)

F4C = 6.25.lc(Wm+W1) = 6,25x0,4x (34,75 + 9) = 109,375(Kg) = 1093,75 (N)

F4r = 6,25.lr W1 = 6,25x1,25x9 = 70,31(Kg) = 703,1 (N)

- The greatest force

The maximum pulling force is used to calculate the selection of conveyor belts according to strength

We have: Fmax = Fp+ F4c -F4r = 5998,7 + 1093,75 – 703,1 = 6389,35(N)

3.1.7 Calculation of ribbon selection

With the type of material to be transported is dry sandstone, this is a materialthat does not have a chemical reaction with the belt, so we choose a multi-layer woven conveyor belt

The parameter to evaluate the strength of the tape rope is calculated

according to the maximum tensile value acting on the wire Fmax according to the following formula:

ax Fm SFz (2.10)