Yokohama Conveyor Belts

CONVEYOR BELTS TECHNICAL IN FORMATION

.c YOKOHAMA CONVEYOR BELTS .li TECHNICAL INFORMATION

Created by U Thaung Myint11/22/2010 Monday

YOKC)HAMA CONVEYOR EEUS


PREFACE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

CHAPTER 1 HOW TO SELECT CONVEYOR BELT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 1.1 NAME OF EACH PART OF CONVEYOR BELT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1 1 Drive System 6 . . . . . . . . . . . . . . . . . . . . . . . . . . 1.1.2 Take-up System 7

1.2 REQUIREMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 1.3 SIZE OF CONVEYING MATERIAL & BELT WIDTH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 1.4 CONVEYING MATERIAL & CAPACITY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

. . . . . . . . 1.4.1 Size of Conveying Material & Belt Width ... 9 . . . . . . . . 1.4.2 Calculation Formula of Conveying Quantity 9

. . . . . . . . . . . . . . . . . 1.4.3 Conveyable Inclination Angle 12 . . . . . . . . . . . . . . . . . . . . 1.4.4 Bulk Density of Materials 13

. . . . . . . . . . . . . . . . . . . . . . 1.4.5 Running Speed of Belt 12 1.5 CALCULATION OF REQUIRED POWER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

. . . . . . . . 1.5.1 Power required for operating unloaded belt 14 . . . . . . m. I - - 1.5.2 Power for moving loaded material horizontally 14 . . . . . . FA 1.5.3 Power required for elevating and lowering belt 14

. . . . . . . . . . . . . 1.5.4 Power required for moveable tripper 14 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . L. 1.5.5Data 15 . .

7.6 CALCULA'i70N' OF BELT TENSION AND TAKE-UP WEIGHT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 1.6.1 Effective Tension . . . . . . . . . . . . . . . . . . . . . . . . . . 17 1.6.2 Slack Side Tension . . . . . . . . . . . . . . . . . . . . . . . . 18 1.6.3 Slope Tension . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 1.6.4 MinimumTension . . . . . . . . . . . . . . . . . . . . . . . . . 20 1.6.5 Running Resistance of Return Side Belt . . . . . . . . . . 20 1.6.6 MaximumTension . . . . . . . . . . . . . . . . . . . . . . . . 20 1.6.6.1 Belt Tension of Standard Conveyor Line Belt . . . . . 20 1.6.7 Multi-Drive System . . . . . . . . . . . . . . . . . . . . . . . . 23 1.6.7.1 Purpose of Multi-Drive System . . . . . . . . . . . . . . . 23 1.6.7.2 Procedure of Calculating Multi-Drive System . . . . . . 23 1.6.7.3 Explanation of Symbols of Multi-Drive System . . . . 24 1.6.7.4 Calculation Example of Multi-Drive System . . . . . . 24 1.6.7.5 Typical driving positions and tension distribution

of Multi-Drive System . . . . . . . . . . . . . . . . . . . . 25 Tension distribution of the typical dual drive system . 26

1.6.8 Tension distribution of the reversible conveyor . . . . . . . 27 . . . . . . 1.6.9 Accelerating Resistance and Accelerating Time 28

I . . . . . . . . . . . . . . . . 1 ".I0 Calculation of Take-up Weight 28 1.7 BELT CARCASSSELECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

1.7.1 Determination of Kind of Carcass and Number of Ply . . 31 1.7.2 Study of Maximum Plies for Troughing . . . . . . . . . . . 32 1.7.3 Study of Minimum Plies . . . . . . . . . . . . . . . . . . . . . 33

. . . . . . . 1.7.3.1 Problem of Sag due to Concentrated Stress 33 . . . . . . . . . . . . . . 1.7.3.2 Problem of Impact at the Chute 34

1.7.3.3 Problem of Load Support . . . . . . . . . . . . . . . . . . 34 1.7.3.4 Method for Determining Minimum Plies . . . . . . . . 38

1.8 MINIMUM PULLEY DIAMETER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 1.9 COVER THICKNESS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

1.9.1 Fabric Belt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 1.9.2 Steel Cord Belt . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

1.10 BREAKER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

CHAPTER 2 HOW TO SELECT BUCKET ELEVATOR BELT . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 2.1 KIND OF BUCKET ELEVATOR BELT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 2.2 CALCULATION OF TEPISION TO BE APPLIED TO BUCKET ELEVATOR BELT . . . . . . . . . . . . . . . . . . . 42

2.2.1 Vertieal Type Bucket Elevator Belt . . . . . . . . . . . . . . 42 2.2.2 Sloped ~ y ~ e b u c k e t Elevator Belt . . . . . . . . . . . . . . 42

2.3 CALCULATION OF REQUIRED POWER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 2.4 DETERMINATION OF'TENSION MEMBER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

2.4.1 Study from the Condition of Use . . . . . . . . . . . . . . . 4 3 4 2.4.2 Study of Carcass Strength against Maximum Tension . . 43 2.4.3 Study of Minimum Pulley Diameter . . . . . . . . . . . . . 44

. . . . . . . . . . . . . . . . . . . . 2.4.4 Studv of Bolt Efficiency 44


HOD OF SPLICING BUCKET ELEVATOR BELT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 2.5.1 Lap Joint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 2.5.2 Splicing by Metalic Clamps . . . . . . . . . . . . . . . . . . . 45 2.5.3 Vulcanization . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

CHAPTER 3 EQUIPMENT OF CONVEYOR SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 3.1 PREVENTION OF IMPACT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 3.2 PREVENTION OF DEPOSITE OF CAKE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 3.3 PREVENTION OF CARRYING MATERIAL FROM BEING TRAPPED . . . . . . . . . . . . . . . .,. . . . . . . . . . . 52

I 3.4 PREVENTION OF CROOKED RUNNING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 3.6 PREVENTION OF ABNORMAL WEAR AT THE SKIRT. THE SCRAPER OR THE CHUTE POINT . . . . . . 55 3.6 DETECTION OF MATERIAL PILE-UP AT THE CHUTE OR DISCHARGING PQlNT . . . . . . . . . . . . . . . . . . . 56 3.7 VERTICAL CURVES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 3.8 DISTANCE BETWEEN TROUGH TYPE ROLLER AND PULLEY AND THEIR DISPOSITION

(TRANSITION DISTANCE) . . . . . . . . . . . . . . . . . . . : . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58 3.9 PREVENTION OF OVERLOADING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59 3. 113 DISPOSITION OF CARRIER AND RETURN ROLLERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

CHAPTER 4 HOW TO USE CONVEYOR BELT PROPERLY . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

. CHAPTER 5 SPLICING METHOD AND REPAIRING METHOD FOR CONVEYOR BELT . . . . . . . 66 5.1 MERIT AND DEMERIT OF EACH SPLICING METHOD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66 5.2 SPLICING BY METAL FATENERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67 5.3 SPLICING BY VULCANIZATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

5.3.1 Factory Splicing . . . . . . . . . . . . . . . . . . . . . . . . . . 68 5.3.2 Field Splicing (Multi-Ply Conveyor Belt) . . . . . . . . . . 68 5.3.3 Dimension for Steel Cord Conveyor Belt . . . . . . . . . . 69 5.3.4 Unicon Belt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

5.4 SPLICING BY NATURAL VULCANIZATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70 5.5 REPAIR OF CONVEYOR BELT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72

5.5.1 Small injury of cover rubber . . . . . . . . . . . . . . . . . . 72 5.5.2 Large injury of cover rubber . . . . . . . . . . . . . . . . . . 72 5.5.3 Small injury reaching carcass ply . . . . . . . . . . . . . . . . 72 5.5.3.1 Fabric Belt . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72 5.5.3.2 Steel Cord Belt . . . . . . . . . . . . . . . . . . . . . . . . . 73 5.5.4 Large injury reaching carcass ply . . . . . . . . . . . . . . . 73

. . . . . . . . . . . . . . . . . . . . . . 5.5.5 Injury of Edge 73

CHAPTER 6 APPENDIX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74 .&I LIFE EXPECTANCY OF CONVEYOR BELT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74 '8.2 DIMENSION AND WEIGHT OF BELT PACKAGE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76 'k 6.2.1 Dimension and Weight of Wooden Drum Package . . . . 76

6.2.2 Dimension and Weight of Simple Wooden Drum Package 77

I . VARIOUS TESTING DEVICES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78 . . . . . . . . . . . . . . . . . . . . . . . . . . b 6.3.1 Separation Tester 78

. . . . . . . . . . . . . . . . 6.3.2 AMSLER's Type Tensile Tester 78 . . . . . . . . . . . . . . . . . . i 6.3.3 SCHOPPER Tensile Machine 79

6.4 CONVERSION TABLE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80


In order to operate coriveyor belt efficiently, it is necessary to analyze our customer's condition of use and to select and design the belt in conformity with the actual condition. The Yokohama Rubber Co., Ltd. has now edited this "Technical Informa- tion of YOKOHAMA CONVEYOR BELT" which is to be the criterion of designing technique of Conveyor Belt. We shall be very happy if this book will be of help for our customers when studying and selecting Conveyor Belt.

"Before you read this book"

The techniques and types of Conveyor Belt are ever progressing day by day making it necessary for us to change parts of this book in future. So, please make much use of this book taking into consideration of the following points.

1. Calculation Method of Belt Tension

The calculation method of belt tension is based upon JIS (Japanese Industrial Standards) established in 1965. But, there are some indefinite points in JIS, which fequire user's decision. Consequently, there are such portions in this book where values and coefficients are determined in accordance with our own idea.

2. Selection Method of Conveyor Belt

It is almost impossible, when selecting belt, to catch the conditions of use and degree of maintenance for each case. Accordingly, there are some parts in this book where safety factor is taken into account for selecting Conveyor Belt. If the belt presently used by our customer is lower with respect to the kind of belt carcass and number '

of ply etc. then the selection method of this book (or i f the belt is used with satisfaction as-to the belt life), it is to be considered that the belt meets with the actual condition of use.

I

w

4

1


3. Requirements for Selecting Belt

It is fundamentally necessary to know the condition of use accurately and to select the belt suitable for the condition of use so as to attain long belt life. There are two stages in selecting belt, viz. planning stage prior to using the belt and studying stage regarding the belt already used. ( 1 ) When conveying material from A to B:

I t is the most indefinite example, if the desired quantity to be conveyed is known but the belt width and running speed are not clear. I t is required in such a case to study line length, belt width and belt speed dividing into several plans.

(2) When the conveying quantity, conveyor length and belt width are known: It is necessary to determine the running speed of the belt.

(3) When all the conditions are known: I t is required:-

a. to investigate if the belt width is adequate for the maximum lump size of the conveying material,

b. to investigate i f it is possible to attqin the maximum conveying volume depending upon the belt width, kind of conveying material, bulk density and belt speed,

c. to calculate the reqyired power and the maximum tension to be applied to the belt, '

d. to determine the kind of belt carcass and the number of carcass ply to be expected from the maximum tension as calculated above, to investigate i f there is no problem in conveying the material and to study the maximum number and minimum number of ply, and beat resistance and chemical resistance,

f- to investigate the kind and thickness of cover rubber and the breaker depending upon the kind of material to be conveyed and the cc:idition of use,

g. to study i f the kind and the construction of the selected belt are suitable for the pqlley diameter and the take-up system.

4. Necessary Properties of Conveyor Belt

The followings are the necessary properties of convey or belt. (1) Carcass strength sufficient for resisting working

tension (2) Adhesion between each ply (3) Wear resistance and cutting resistance (4) Fatigue resistance a. Resistance against repeated flexure by pulley

and variation of working tension b. Resistance of cover rubber against deteriora-

tion due to sunlight, ozone and conveying material

c. Resistance against deterioration of performance due to water permeation

d Resistance against concentrated stress due to partial injury

(5) Troughability against carriers When the lateral rigidity of the belt is high, the belt does not easily become adaptable to carriers and is liable to cause crooked running.

(6) l mpact resistance The resistance against the impact by conveying material a t the chute.

(7) Spliceability (8) Elongation of belt during operation

Adaptability of take-up movement and elongation of belt.


CHAPTER 1 I HOW T O SELECT CONVEYOR BELT

1.1 NAME OF EACH PART OF CONVEYOR BELT

1.1.1 DRIVE SYSTEM (m) Although there are different names of drive - (a ) system, our company takes the following classification. U

a) Single Drive b) Snubbed Single Drive a) b) S~ng le Drlve

The pulley to be provided closely so as to increase the wrapping angle of the driving pulley is called as "snub pulley". The drive system of this type is called as "snubbed single drive". b) Snubbed S~ng le Drive

c) Tandem Type Single Drive This system drives only one shaft.

d) Tandem Type Drive One shaft is directly driven and another snan receives the power through the gear br the chain, thereby two shafts are driven. c ) Tandem Type Single Drive

e)f) Dual Drive Two shafts are driven respectively by a separate motor. This system is used when two shafts are closely positioned and the running resistance between two shafts can be ignored.

g) h) Multi-Drive System This is the system for driving more than two dl Tandem ~ y p e Drive

shafts respectively by a separate motor, where - each drive is positioned as apart as possible (for example when driving the head and the tail).

a-

1 e ) f ) Dual Drive


I g) h) Multi-Drive System

(a) Screw Type '

111 (b) Gravity Type

Horizontal Gravity Take-Up

(c) Carriage with Gravity Weight Suspended Type


(K) Automatic Tension Controling Type

Take-up System (Power Take-up)

@=) Power Take-up System & Tension Detector

Motor \

Brake Take-up carriage Tension Delector

/ Wire rooe /

1.2 REQUIREMENTS

When selecting conveyor belt the following require ments should be satisfied. a) Relation of the size and shape of conveying

material with the belt width. '

bJ Relation of the desired conveying volume with the belt width, carrier anglq and running speed of belt.

c) Relation between the inclination angle and slipping of conveying material

d) Relation between the tension to be applied to the belt and the ultimate strength of the belt

e) Number of carcass ply suitable for use (Rela- tion between required maximum and minimum number of ply)

i) Conveyor belt is supported mainly by means of carriers and the belt requires sufficient rigidity to hold conveying material.

ii) Belt should adapt to carriers well so as not to make crooked running.

iii) Belt shou Id have enough impact resistance, because it is subjected to the impact caused by conveying material a t the chute.

f) Wear out of the belt by conveying materials, and the cover rubber and other construction of the belt.

g) Other Requirements i) Fatigue due to flexure at the pulley ii) Splicing method of the belt


SIZE OF CONVEYING MATERIAL & BELT WIDTH

The recommendable maximum lump sizes of the conveying material are as shown in Table 1.1

Maximum Lump Size (rnm) Maximum Lump Size (mm)

Belt Width Belt Width (mm) In case of 10% of load is In case of 10% of load is (mm)

uniform lump size maximum lump size uniform lump size maximum lump size

i

350 50 100 1,500 305 505

400 50 125 1,600 330 550

450 7 5 150 1,800 355 610

500 100 180 2,000 380 660

600 125 205 2,200 430 760

750 150 255 2,400 455 81 0

900 175 305 2,600 485 865 -

1,050 200 355 2,800 510 910

1,200 250 405 3,000 580 1,010

1,350 280 450 3,200 6 10 1,065 < I 1.4 CONVEYING MATERIAL & CAPACITY - -

1.4.1 SIZE OF CONVEYING MATERIAL & BELT WIDTH

When the size of conveying material is too large

t in comparison with the belt width, various kinds of trouble may take place during operation. So, it i s ,

desireable that the belt is used in accordance with the following standards as shown in Table 1.2

) [TGEjT] Maximum size of materid & minimumbdt width (mm)

Max. diagonal length 100 150 200 250 300 400 500 of lump -

! 1.4.2 CALCULATION FORMULA OF CONVEYOR CA-

I PACITY

I Conveyor capacity is calculated in accordance with the following formula. When the belt i s inclined, it is required to take into consideration of t h ~ ~~mpensation.

Q t = 6 0 . A . r - v . . . . . . . . . . . . . . . . . . . . . . . (1) Qt : Conveyor capacity (t/h) A : Loaded cross sectional area of conveying ma-

terial (m2 ) ... Refer to Fig. 1.4.1 & Table 1.4. 7 : Bulk density of conveying material (t/m3)

... Refer to Table 1.8. v : Belt speed (mlmin.)


(-7) Flat belt ml.s) Troughed belt

Surcharge Angle s ~ ~ 3 ) Value of K

Surcharge Angle

Trough Angle I 0" 20° 30"

0 (Flat) 0.0292 0.059 1 0.0906

20 0.0963 0.1245 0.1 538

25 0.1 112 0.1285 0.1660

30 0.1248 0.1488 0.1757

45 0.1485 0.1698 0.1915

(-4) Value of A (Load Cross Section)

Angle

Unit: 10-2rnz

Trough Angle 0" 20" 25' 30" 45"

Surcharge Angle \.

Belt Width (rnm \ 19" m0 30" 100 20° 30 lo0 200 300 10" 200 300 10" 200 300

400 0.28 0.56 0.86 0.93 1.20 1.48 1.07 1.24 1.60 1.20 1.43 1.69 1.43 1.63 1.84

450 0.37 0.74 1.13 1.21 1.57 1.94 1.40 1.62 2.09 1.57 1.86 2.22 1.86 2.14 2.41

To be safe for design capacity of high speed belt (over 200m/min.), a lo0 surcharge angle had best be considered.


1.4.3 CONVEYABLE INCLINATION ANGLE

The conveyable inclination angle varies depending upon the nature and the shape of the material to be conveyed, but the angles as shown in Table 1.7 are the norminal ones for the ordinary belt with the through angle of 20". Table 1.7 - Conveyable inclination angle

(-73 CONVEYABLE INCLINATION ANGLE

Material Max. Angle

Cement (Powder) 22" Coal (Crude) 16 - 18"

(Slack) 22" Coke 18 -- 20" . - --

Concrete 12 - 26" Sand 20" Grain 20" Gravel 15" Lime (Powder) " 23" Wood (Chip) 25"

(Log) 10" Ore (Crushed) 20"

(Mixed)

(Luma) Paper Package I 16"

*Paper Package 1 "25 -45" Macadam (Crushed) 20"

(Mixed) 18"

(Lump) 16" Salt (Powder, rock) 20" Sand (Ordinary) 20"

(Dried) 15O Stone Aggregate (Powder) 23" Sulfar (Powder) 21"

* In case of package conveyor belt.

1.4.4 BULK DENSITY OF MATERIALS

(-8) Bulk density of materials

Material

Sand (Dry)

(Common)

(Wet) (Foundry)

Gravel

Macadam Limestone Powdered Limestone Clay (Dry)

(Wet) Earth (Common)

(Wet) Mud Cement (Powder)

(Clinker) (Portand Cement)

Concrete Ammonium Sulphate (Dry-Wet)

Cinder Coal Crude

Lump

Coke (Lump) (Dust)

Gypsum Quick Lime Grains Soya beam

Rice

Wheat

Sugar Raw Refine

Wood (Hardwood) (Softwood) (Hardwood) (Softwood)

(Wet)

Woodchip

Pulp

Bark Fuel wood

Lumber Sawdust wood AS^ (Dw)

(Wet) Ore l ron

Copper Zink Potash Nickel

Bulk Density


Bulk Density

cific Gravity) Brass

I

1.4.5 RUNNING SPEED OF BELT

Running speed of the belt is a principal factor to increase the conveying quantity. But, the speed is critical depending upon the nature of conveying material.


1.5 CALCULATION OF REQUIRED POWER -

There are two methods of calculating required power, viz. to calculate based upon experiment and to calculate by respectively calculating frictional force and gravity a t each portion of the belt and also the effective tension to be applied to the belt. But, the method based upon experiment is usually employed, because generally the carrier weight and other details are not clear.

Further, this calculation method is classified into DIN (German standard), Hetzel, Goodyear and Goodrich systems. Although thet-e are slight differences among them, it cannot be said which is definitely accurate. Moreover, there is no remarkable error in either of them causing trouble with the belt. The following formula is in accordance with JIS (Japanese l ndustrial Standards) established in 1965.

P : Required power (kW)

PI : No load power (kW)

P2 : Horizontal load power (kW)

P3 : Lifting load power (given with negative sigh for descending belt) (kW)

f : Coefficient of rotational friction of the idler

W : Weight of moving part other than the conveying material (kg/m)

v : Belt speed (mlmin.)

Q : Conveyor length (horizontal center distance between head and ta i l pulleys) (m)

Q, : Corrected value of the center distance (m)

7 : Bulk density of conveying material (t/m3)

Qt : Capacity (tlh) Qt = Qm . y Om: Conveying volume ( m3 /h)

h : Vertical height of ascending and descending lift including the height of the tripper, if any. (m)

1.5.1 POWER REQUIRED FOR OPERATING UNLOAD ED BELT

The required power is not proportional to the conveyor length. It is because the abrasion loss of pulley, skirt board and etc. and the energy loss required for bending the belt exist without relating to the conveyor length, particularly because of which the conveyor length of the belt plus compensated value is experimentally propor- tionated to the required power.

1.5.2 POWER FOR MOVING LOADED MATERIAL HORIZONTALLY

1.5.3 POWER REQUIRED FOR ELEVATING AND LOWERING BELT

Note: h he value becomes negative in case of the lowering belt.

1.5.4 POWER REQUIRED FOR MOVEABLE TRIPPER

When the power required for operating the moveable tripper is unkonwn actually, it is necessary to apply the required power in accordance with Table 1.9. The moveable tripper is such a tripper as to run by taking power from the conveyor belt. The required power of moveable tripper i s to be preferably as shown in Table 1.9.


POWER REQUIRED FOR MOVEABLE TRIPPER (Pt) (kW)

I 1.5.5 DATA

(1) Belt Weight (W, ) (kglm)

f i) The weight o f fabric belt is calculated i n

accordance w i t h the fol lowing formula.

W1 = Belt Width (cm) x No. o f Ply (P) x Carcass Thickness (mm/P) + T o p Cover Thickness (mm) + Bottome Cover Thickness (rnm) x p x 1/100 .. . . . . . . . . . . . . . . . . . (6)

WI = Belt Weight per mtr. length (kglm)

p = Coefficient depending upon k ind o f belt carcass. -

- -

Kind of Carcass Tensile Thickness Strength

Carcass Designation ( ~ ~ l ~ ~ p ) (mm/P)

NV- 50 50 0.7

JNN-100 100 0.8

NN-120 120 0.8

NN-150 150 0.9

N N-200 200 1 .O

Nylon NN-250 250 1 .I

Fabric N N-300 300 1.2

N N-350 350 1.3

N N-400 400 1.4

NN-450 450 1.5

NN-500 500 1.6

NN-600 600 1.7

VN-100 1 00 1 .O Vinylon

VN-120 120 1 .O Fabric

VN-150 150 1.1

ii) I n case o f Steel Cord Conveyor Belt calculation is made i n accordance w i t h the fol lowing forrnu- la. (Please refer t o our ST Belt catalogue regarding the standard value.)

WI = Belt Width (m) x Std. Value (kg/m2) ?

l ncrease o r Decrease against Std. Cover Rubber Thickness (mm) x 1.2 (kg/m2 . . . . . . . . . (7)

(2) Idler Weights The idler referred here is made o f steel pipe, al- through there are many other kinds o f roller.


3-equal-roll Flat Type Belt Width Idler Diam. Troughing Return-Idler

(mm) (mm) Idler(Kg/set) (Kglset)

400 89.1 6.6 5.0

450 89.1 7.1 5.4

500 89.1 7.5 5.9

600 89.1 8.3 6.8

750 114.3 13.2 1 1.6

900 1 14.3 15.1 13.4

1050 139.8 21.3 18.9

1200 139.8 23.6 21 .I

1400 165.2 36.6 32.6

1600 165.2 41.4 36.6

1800 165.2 47.4 42.5

2000 165.2 52.2 46.5

(3) Value of moving part, W for calculation (kglm) When calculating actual required power, it is difficult to preliminarily know W value accurately. So, a certain assumption is to be set. The standard value used by our company is as shown below.

WI : Belt Weight (kglm)

W'c: Weight of rotational part per set of carrying idlers (kg)

Qc : Carrying idler spacing (m)

W'R: Weight of rotational part per set of return idler (kg)

QR : Return idler spacing (m)

Wc : Carrying idler weight (kglm)

WR : Return idler weight (kg/m)

Table 1.13 shows the medium values for the belt weight of each width provided that the carrying idler spacing is 1.2 m and the return idler spacing is 2.4 m. Special care must be taken for Steel Cord Conveyor Belt, because the belt weight considerably differs.

Weight Belt Width Belt Weight WI of Moving Part

(mm) (Kglm) W (Kglm)

400 4.5 17

450 7 A 22

500 7.2 24

600 9 28

750 13 42

900 15.5 49

1050 23 72 .

1200 26 81

1400 33 112

1600 38 125

1800 46 150

2000 5 1 160

Note: Calculation is made in accordance with Was shown abow ir principle. I t is necessary, however, to make recalculatior accurately ascertaining the weight of carrying idler, returr idler and belt tare in case of long span and high tensilt strength belt.

(4) Coefficient of rotational friction of the idler (f ] and corrected value of the center distance (Qo] The Coefficient of rotational friction of idle1 ( f ) is not exactly kn0w.n because it depends i upon the method of bearing seal of idler and j working condition, but it- is nominally shown in Table 1.14.


@bnstruction Character of System

w m using idlers with Minary rotational friction

mnce, of which installa- bn is not so good. -

n using idlers with ( &cularly little rotational (322 66 WTm yesistance,of which

allatisn condition is

calculating braking n,, 156 "." . - mx of lowering conveyor I

gutput of Electric Motor (Pm) The output of electric motor is calculated by h e following formula.

i : Output of Electric Motor (kW)

: Required power (kW)

Efficiency of machine

1.6 CALCULATION OF BELT TENSION AND TAKE-UP WEIGHT

1.6.1 EFFECTIVE TENSION

The difference between the tension on the tight side and that on .the slack side is called as "effective tension". Namely, the'effective tension is created by transmitting motor power.

The effective tension (Fp) is calculated in accordance with the following formula.

FP : Effective Tension (kg)

P : Required Power (kW)

v : Belt Speed (mlmin.)

F1 : Tight Side Tension (kg)

F2 : Slack Side Tension (kg)

Fig. 1.9


1.6.2 SLACK SIDE TENSION

Slack side tension is the minimum necessary tension required for creating frictional force corresponding to the effective tension on the driving pulley.

1.6.3 SLOPE TENSION

Slope tension is the tension to be created a t the upper pulley by the belt tare when conveyor is sloped and it is calculated in accordance with the following formula.

p : Coefficient of friction between driving pulley and belt (See Table 1. 15.)

0 : Angle of belt wrap a t drive

e : Base of natural logarithm 1 - : Drive factor .... Refer to Table 1.16.

If assumed to be:- 1

@ e - l = R R: Drive factor

F3 =WIQ1 sina=W,h .. . . . ...... . . . (12)

FJ : Slope tension while running (kg)

W, : Belt weight (kglm)

i?, : Length of the conveyor slope (m)

a : Angle of inclination (")

h : Lift (m)


1.6.4 MINIMUM TENSION

It is not advisable, from the standpoint of operating belt, that the belt sags too much between idlers. The tension required for preventing such sag is called as "minimum tension"

50 Qt Carrying Side F4 = 8. Rc(= + Wl 1. . . ( 13.1 )

50 . . . . . . . . . . Return Side F4 = 8' 1 1 ~ W1 (13.2)

F, : Minimum Tension (kg)

R, : Carrying ldler Spacing (m)

W, : Belt Weight (kglm)

Q R : Return ldler Spacing (m)

Whichever larger value of (13.1 ) or (1 3.2) shall be taken up. In order to make the calculation simple the carrying idler spacing is determined as 1.2 m.

1.6.5 RUNNING RESISTANCE OF RETURN SIDE BELT

Although it is not necessary to take into consideration of the running resistance in case of a short belt, that of the return side belt should be calculated when the conveyor belt is of long span or a reversible one.

1.6.6 MAXIMUM TENSION

1.6.6.1 Belt tension of standard conveyor line belt

The method of calculating the maximum tension to be applied to the belt differs depending upon the driving system and the form of the conveyor line, so please calculate the maximum tension in accordance with the following method respectively.

FR = f (W, + WR (I1 + Ro) (kg) . . . . . . . . . . (15)


Drive a t or near Elevating Conveyor with Drive at or near Head.

'"" "' F, + Fp- FR

b) Horizontal Conveyor with Drive at or near Tail.

a @- FpR

I Or T- F,

+F4 Use , the larger one for Fm

FP( I + R) -@ FM { or

F4 + F3 + Fp- FR

I -@

I

FM=F~( I + R) or F, + F3 +Fp-FR Use the larger one for Fm

d) Elevating Conveyor with Drive at or near Tail.

\- I 1

FM I F4 :Fa + Fp- FR -@

I T- FP(;:N} FM

@- F, + Fp.

F ~ ( I +R)-FR+F~ Use the larger one for Fm

F4 + F3 + Fp- FR I


e) Lowering Conveyor with Tail End Drive.

[P, + P, < P, (Absolute rate)

(Hold back)

Fp( I+ R) + F3 + FR FM{ or Use the larger one for FH

Fp+ F, + F3 + FR

f) Lowering Conveyor with Tail End Drive

IP, +P2 >P, (Absolute rate)

(No Hold back)

I Use the larger one for F r

g) Lowering Conveyor with Head End Drive.

[PI +P, <P3 (Absolute rate)

(Hold back)

Use the larger one for Fp

FPI ( I +R)

h) Lowering Conveyor with Head End Drive

[PI + P2 > Pa (Absolute rate) (No Hold back)

@ FPR I @ F,+F, +FR-FP I

&j~, + F3 + FR

Use the larger one for Fp


i) Elevating Conveyor with Drive located part way down the slope in the return run.

Use the larger om for Frn

The running resistance on the return side (FR) may be omitted in other cases than long span or reversible belt for a) - hl lines. F,f is the effective tension in the case of horizontal no

1.6.7 MULTI-DRIVE SYSTEM 1.6.7.1 Purpose of Multi-drive system

In case of a comparatively horizontal and long span line the value of the running resistance in the return side becomes considerably large. In such a case this system is good for reducing the return side running resistance, which was absorbed a t the tai l driving portion from the head driving portion. I 1.6.7.2 PROCEDURE OF CALCULATING MULTI-

DRIVE SYSTEM

(1) Obtain total required power, P. (2) Obtain the running resistance in the carrying

side (Fc) and the running resistance in the return side (F R ) respectively.

(3) Consider the number of standard motors to satisfy the total required power, P. Further, consider the ta i l motor with the power of more than 0.4 times of the horizontal no load power, P, and also corresponding to the required number of motors having the standard power.

(4) The effective tension of each driving pulley from each motor shall be considered similar. (The consuming ampere of each motor shall be checked and set so as to be equal after installation).

(5) Calculate the necessary tension and the tension to be applied to each portion of the belt in accordance with (4).

1 2 belt.


1.6.7.3 EXPLANATION OF SYMBOLS OF MULTI- DRIVE SYSTEM

The following symbols are used for the tension calculation formula for obtaining the maximum tension of the multi-drive system. These symbols are in addition to those contained in JIS-6-8805.

Fp: Total effective tension (kg) F ~ H : Head effective tension (kg) F P H ~ F p ~ 2 : Effective tension of 1st and 2nd

head drives F ~ T : Tail effective tension (kg) Fc: Carrier side running resistance (kg) FR: Return side running resistance (kg) 6 H: Angle of belt wrap at head drive (radian) 6 ~ : Angle of belt wrap at tail drive (radian) p ~ : Coefficient of friction between head drive

pulley and belt p ~ : Coefficient of friction between t a i l &e

pulley and belt F1 H : Head tight side tension (kg) FIT: Tail tight side tension (kg) F ~ H : Head slack side tension (kg) F ~ T : Tail slack side tension (kg) FH 1.2 or F 1.2: Tension between I s t and 2nd head

drives Wc: Carrying idler roller weight (kglm)

1.6.7.4 CALCULATION EXAMPLE OF MULTI-DRIVE SYSTEM

Belt width: 900 mm Trough angle: 20" Belt speed: 200mlmin. Carrying material: Limes- Carrying quantity: 1500 t/h tone Horizontal conveyor

(1) Obtain the required power.

PI = 0.06 x 0.022 x 76.3 x 200 x 51000 + 66 = 367

(2) Obtain the total effective tension (Fp), the return side running resistance (FR) and the minimum tension ( F, ). FR = 0.022 x (25 + 6.3) x 5066 = 3,490 kg

Fc=f (W, +WC+WM) (Q+Q,)+-W~h(kg) (16.2) 6120 x 733.7 F p = 200 = FPH + FPT = 22,451 kg

FR . . . . . . . . . . Refer to the formula (1 5). Qt Fc = Fp - FR = 18,961 kg

WM = 0.06.v (kglm) . . . . . . . . . . . . . . . . (1 6.3) = 1,875 kg (Sag = 1 %) Qc = 1.0 m

- -- g; WM : Carrying quantity per mtr. (kgJm) (3) Motors with the total ~apacity of 1,000 KW

shall be installed based upon the total required power of 91 7 KW as calculated in (1 ).

f : Coefficient of rotational friction of the idler (4) The following plans are considered for deter-

h: l i ft (m) mining the driving position and distributing the Qt: Carrying quantity (t lh) motors with the total capacity of 1,000 KW Q: Horizontal conveyor length (m) based upon the formula of "Horizontal no load

Q : Corrected value of the center distance (m) power PI x 0.4 = 278.1 x 0.4 = 120 KWH. V : Belt speed (mlmin)

Plan 1 Plan 2 P: Required power (s'haft horsepower) (kw)

drive at Installed motor 200kW x 2 Sets 250kW x 2 Sets 1 1,226 kg

Installed motor 2OOkW x 2 Sets 250kW x I Set ;Iriv: at ' Effective tension F M 8,981 kg ea

5,613 kg Tail Installed motor 200kW x 1 Set 250kW x 1 Set drive Effective tension Fm 4.490 ka 5.61 2 kn


in the driving positions and

=0.25, & 1 = & 2 =

the tension at

Tension at each point I Plan 1 I Plan 2 I I

Point A 1 21.956 ka 1 22.705 ka

Point B 12,975 " 1 1,479 " FPHZ 8,980 " 5,613 "

. Point C 3.995 " 5.866 "

Point D 7,485 " 9,356 " Fm 4.490 " 5.61 2 " Point E 2,995 " 3,744 " Fc 18,961 " 18,961 " .

1.6.7.5(A) Typical driving positions and tension r distribution of the multi-drive system

(1 ) Horizontal Conveyor with Drives at Head anc' I Tail

Whichever larger value of:

FM=FPT.RT+Fp-F~+Fa Or FI f Fs +FP-FR


I CHAPTER 1 ]

(3) Lowering Conveyor (No holdback) with Drives at Head and Tail


F u = F p ~ . R ~ + FP-FR-F~: Or:F, +FP-FR-F~

(4) Horizontal Conveyor with Multi-Drive System 1

1 Or @ F, +FP-FR-FPHI

e ~ 2 0 2 - 1 FP2 = Fp (kg). . . . . . . . . (16.5)

eP202 e ~ ~ e ~ - 1

Whichever larger value of:- FM= FPT .RT + Fp- FR or F4 + Fp- FR

Effective tension distribution of tandem drive system:

e ~ 2 8 2 - 1 F p 2 = &282eP18~ - 1 FP (kg)

When the frictional connection is perfectly utilized, the effective tension distribution of the tandem drive system is similar to that of the dual drive system. There are problems regarding both tandem and dual drive. So, please consult with us.


t .& TENSION DISTRIBUTION OF THE TYPICAL DUAL DRIVE SYSTEM

. , ' Horizontal Convevor with Dual Drive at or near

1.6.8 TENSION DISTRIBUTION OF THE REVERSIBLE CONVEYOR 1

1. Operation in reverse direction


F M= Fp2- & + FP Or F4 + FF- FR

2. Operation in regular direction a) I n case of F MR> F ~ N or F ~ N


FM=FPR(I+R)+F~N Or FIR+ FPR+FPN


b) In case of FMR<F~N or F4N


FM=FPN( I +R) or F, N+FCN

c) Other combinations may be considered, about which calculation will be made by us upon request.

1.6.9 ACCELERATING RESISTANCE AND ACCELE- RATING TIME

The relation between accelerating resistance and accelerating time, when starting the belt, is a: shown below.

FA: Accelerating resistance (kg) : Accelerating time (sec.)

The starting tension when starting the belt gently is calculated as 135% of the maximum tension a t the time of normal loaded running (the accelerating resistance is 35% of the maximum tension at the time of normal loaded running). The starting time can be determined by the formula (19), which is developed from the formula (1 7).

50 v(Q+Q,) (W, +-Qt) t = 3v ....................... (18)

2 0 6 F ~

1.6.10 CALCULATION OF TAKE-UP WEIGHT

(1 ) Types of take-up There are screw type, gravity type, carriage with gravity weight suspended type, and power take-up type, about which please refer to 1.1.2. (2) Calculation of Take-up Weight 2.1 The take-up weight is fundamentally 2 times of

the tension applied to the take-up position. 2.2 Method of determining take-up weight depend-

ing upon the take-up position.


(c) Horizontal Conveyor with Drive at or near Head and with take-up system provided a t Tail

(a) Horizontal Conveyor with Drive a t or near Head and with take-up system provided a t Head '-

, . .

Take-up weight = 2Fp- R or 2(F4 - FR)

rlh~hichever larger value)

Take-up weight =~(FP.R+FR) or 2F, (whichever larger value)

~rizontal Conveyor with Drive a t or near and with take-up system provided middle

1 1 ~ ~ d n between Head and Tail.

- F4 -.FR 1-

I ' I - I ' ' Take-upweight =2(FpqR+-Fa) or 2(F4 - T F ~ )

I (whichever larger value)


@5iiii$z) (a) Elevating Conveyor w i t h Drive a t o r near Head (c) Elevating Conveyor w i t h Drive a t o r near Head

and w i t h Take-up System provided a t Head and Take-up System provided a t Tai l

(b) Elevating Conveyor w i t h Drive a t o r near Head I n case o f (a): and w i th Take-up System provid& middle Whichever larger value o f 2FpR o r 2 ( F 4 + F 3 - port ion between Head and Tail F R )

I n case o f (b):

F3 = Wl h Q' F3'= W1 h- Q

Consequently, the take-up weight shall be which- Q r

ever larger value of 2 [FPR +y (FR - F B OT

2 [ F ~ +yr (F3 - FR) ] I

I n case o f (c) : Whichever larger value o f 2(FPR + F R - F3) or 2F4


d

1.7 BELT CARCASS SELECTION

.7.1 DETERMINATION OF CARCASS AND NUMBER OF PLY STUDY FROM TENSION

he maximum tension, FM to be applied to the

e belt width is usually used for b Value. More

the number of ply shall be determined from Standard Permissible Tension Table. relation between breaking tension of the fiber the standard permissible tension is called as the

In case of the fibrous tension layer:

b x n x B S . . . . . . . . . . . . . (20)

SF: Safety Factor FM: Maximum tension (kg) b: Belt width (cm) n: Number of ply BS: Breaking strength of tension layer (kglcmp)

(b) In case of the steel cords tension layer:

FM x SF, . . . . . . . . . . . . . . ST-NO= b (21)

FM : SF, :

ST - No: Breaking Strength of Steel Cord belt per 1 cm width (kg/cm) Maximum Tension (kg) 1st Safety Factor (Safety factor against maximum static load). Generally more than 7.

Standard Permissible Tension for Vulcanized Splices

Carcass Pexmissibl~ Tension

Designation

NV- 50 4.1 kglcm ply NN-100 8.3 kglcm ply

NN--120 10.0 kglcm ply 0 .- 2 NN-150 1 2.5 kglcm ply m LL NN-200 16.6 kglcm ply C 0 - NN-250 20.8 kglcm ply >. z NN-300 25.0 kglcm ply

NN-350 29.1 kglcm ply NN-400 33.3 kg/cm ply NN-500 41.6 kglcm ply

NN-600 50.0 kglcm ply

c VN-100 8.3 kglcm ply 0 0 - .- $4 VN-120 10.0 kglcm ply 5 VN-150 12.5 kglcm ply


1.7.2 STUDY OF MAXIMUM PLIES FOR TROUGHING

When the belt is not adaptable to the carrier angle, it is liable to cause crooked running. Ideally it is necessary that the belt touches the center roller without being loaded. It is quite indispensable in the case of U-Type Conveyor. When the trough angle is 20" - 30°, the belt will become adaptable to the trough while using, even if the initial condition of the trough is slightly unsatisfactory. It is, however, the matter of degree. It is required to select less ply depending upon the trough angle.

Maximum Plies for Trough Angle of 20° . \ Belt width I

NV- 50 1 With these widths and kjnds of canvas there i s no problem as the maximum

NN-100 number of ply.

Maximum Plies for Trw* .Angle of 30°

there is no problem as the maximum

number of ply.

N N-500 - - - 4 5 6

N N-600 - - - 4 5 6

VN-100 4 4 6 7 8 8

VN-120 4 4 6 7 8 8

VN-150 3 4 5 6 7 8


1.7.3 STUDY OF MINIMUM PLIES

Some degree of safety factor is taken into consideration when determining the minimum number of ply. So, our users should employ the specification of belt being actually used as the proper specification, if no trouble has been taken place for more than two years in the past due to the following causes. Belt must be of over ply due to the concentrated load given by big lumps of the material between carriers and impact at the chute. Namely, the number of ply should be determined finally after studying the necessary number of ply for each item as mentioned later.

1.7.3.1 Problem of Sag due to Concektrated Stress

Study of minimum number of ply against the problem of sag being increased between carriers by lumps of carrying material. As to the problem of sag it is usual that the sag is applied in such a manner that it is kept within 2% of the carrier spacing. But, abnormal sag is created between two carriers when big lumps are loaded, even i f the total carrying quantity is unchanged. Table 1.24 shows the minimum numbers of ply against this problem.


1.7.3.2 Problem of Impact at the Chute

Study of minimum number of ply against impact a t the chute, Various types of carrier are used a t the chute such as ordinary carriers, cushion rollers and zero pressure rubber tires etc. Further, the materials may fall down between carriers or upon carriers (or cushion rollers). When the impact is considered, i t s force must naturally be taken into consideration. In this case the following factors shall be taken up. (a) Weight and Shape of Maximum Lump Various shapes may be considered, but generally they are to be considered quite irregular. (There is such an exceptional case like boulders before being crushed). (b) Dropping Speed The dropping speed is affected by the dropping height (height of chute). (c) Chute Angle Component of a force varies depending upon the chute angle and the impact force against the belt differs accordingly.

CT-] Weight of Lump (kg)

1.7.3.3 Problem of Load Support

It is stated in Para. 1.7.2, "Study of Maximum Plies for Troughin" that the belt must be adaptable to the carrier angle. I f the belt is too soft, it may be deformed and caught in the gap between 3-roll troughing idlers because the carriejs are angular. In such a case it is feared that the belt will cause ply separation. Table 1.27 shows the study of minimum number of ply in such a case.

Table 1.23 Weight of Lump (kg) When the actual weight of the lump i s known (or can be calculated), i t s value is to be used. As an expedient please use the following Table. -Please note, however, that in this Table cubic materials are used for the sizes up to 150 mlm, and rectan- gular or plate like materials are used for the sizes of more than 150 mm.

Bulk Density (tonlm3

0.5

0.8

1 .O

1.2

1.5

2.0

2.5

Lump S;re (mm)

50

0.1

0.16

0.2

0.24

0.3

0.4

0.5

300

20

32

40

48

60

79.5

99.5

350

28

45

56.5

68

85

113

141

75

0.38

0.6

0.75

0.9

1.1

1.5

1.8

400

42.3

67.5

84.5

101

127

169 - 212 -

175

4.0

6.4

7.9

9.5

9.6

15.9

19.9

100

0.85

1.4

1.7

2.0

2.6

3.4

4.2

200

5.9

9.5

11.8

14.2

17.7

23.6

29.5

125

1.6

2.5

3.1

3.7

4.7

6.3

7.9

225

8.4

13.5

16.8

20.2

25.2

33.6

42

150

2.9

4.5

5.7

6.8

8.5

11.4

14.2

250

11.5

18

23

28

34

46

57.5


1.25 & 1.26 - Study of Minimum Number

use Table 1.23 for the weight of

rding the speed and the chute angle a in standard fall shall be considered.

straight dropping.

Value of sin2 A

Chute angle Sin2 A

15 0.067

20 0.1 17

25 0.179

30 0.250

35 0.329

40 - 0.413

45 0.500

50 0.587

55 0.671

60 0.750

65 0.821

70 0.883


Example of compensating the weight of carrying material when using Table 1.26. Actual lump weight: 20 kg, Chute construction - Total fall: 2.0 m, Chute angle: 45, & Direct fall height: 0.3 m.

If this formula is used, it is unable to design when the chute condition is unknown. So, it is necessary to investigate the condition of use. If it is obliged to design with the condition of use unknown, the chute condition designed should be clearly stated.

When the condition of use i s unknown, the standard calculation shall be made with the total fall of 1.5 m, chute angle of 60" and the direct fall height of 30cm from the extreme point of the chute to the belt. In this case the compensation value shall be 0.8 as calculated below.

(T-8 Ordinary Belt

Problem of Load Support

Spacing of carrying idler is assumed to be 1.2 m. The unit carrying quantity between carriers will come into question. So, firstly calculate the carrying quantity per mtr and make study by putting the calculated quantity into Table 1.27.

Qt x 16.6 Carrying quantity per mtr. WM :

v (kglm)

. . . . . . . . . . . . . . . . . . . . . (16-2) Qt: Carrying quantity (tlh) v : Belt speed (rnlmin.)

Note: I . Each figure above the oblique line I/) is me value in the case of ordinary carrier and the figure below the oblique line shows the value in the case of cushion roller or zero pressure tire.

2. When the distribution of the maximum lump is more than 25%, please use the carcass of I ply over.


Carrying Quantity (kglm)

Carcass PI y Belt Width

'1 00 100 38 90 1 54 901-1200 r 120 120 15 60 120 1 200 over

60 128 225 406 up to QOO

1 50 150 85 177 345 QOl"1209

1 28 255 1200 over

200 112 233 457 1 901-1200 I 1 2 5 0 I I 75 1 1 5 0 1 316. 1200 over

90 225 496 900

1 58 360 698

90 225 495 1200 over

126 315 693 1260 up to 900

350 221 504 978 901-1200

126 315 M3 over 1200 over


1.7.3.4 Method for Determining Minimum Plies

@TzFm8)

1.8 MINIMUM PULLEY DIAMETER

If the pulley diameter is small, it is advantageous from the standpoint of equipment cost. But, the smaller the pul!ey diameter and the thicker the belt fabric, the more violent becomes the carcass fatigue. So, the standard minimum required pulley diameter was determined as below. Namely, the values of head, drive and tripper pulleys are as shown in Table 1.29. The tail take-up pulley is to be 80% of the standard value, and the values of bend, rotation snub pulleys are 60% of the standard values. Safety Factor and Pulley Diameter: The ratio of actual working tension to standard permissible tension is assumed to be A.

A = Fb x 100..(23.1) Std. Permissible Tension x n

Fb = - FM (kg) b

FM : Maximum Tension (kg)

b: Width (mm)

~ t d . Permissible Tension = BS . . . . . . . (23.2) SF Std.

BS: Breaking Strength (kg/cmP) SF Std.: Std. Safety Factor

In case of ordinary carcass fabric: For general use . . . . . . . . . . . . . . . . 12

. . . . . . . . . . . . . . . . For heat resisting 15 n: Number of plies

Obtain K value based upon A value in Table 1.29 and the minimum value shall be obtained by multiplying the standard value by K%.

Note: When the value of more than 7ply is selected in determining the number of ply, the maximum number of ply in principle shall be within 6 ply by selecting the carcass in one rank or more.


(TABLE 1.30)

Std. Minimum Pulley Diameter (Head & Drive Pulley) (unit: (mrn)

8P No. of Plies

Fabric \ 6P 7P 3P 4P 5P


1.9 COVER THICKNESS

1.9.1 FABRIC BELT

It is very difficult to determine the kind and thickness of cover rubber. For example, although it is understood that the cover rubber of 6 mm thick will be more advantageous than that of 5 mm thick in i t s life expectancy, it is unknown if the latter cover rubber will be damaged or to what extent i t s life will be shorter than the former. (For heat resisting and oil resisting uses it is of cource necessary to select the belt suitable for the use). The following Table shows the nominal standard thickness. However, the actual thickness' shall be determined in accordance with the user's intention.

(~-1) Cover Rtrbber Thickness for General Use

Thickness (mm) Carrying Material

Top Cover Bottom Cover

(1) Non-abrasive materials 1.5 s 1.5 such as cereals, chips, cotton, cement & dust 2 1.5

coal 3 1.5

(2) Slightly abrasive materials such as sand, soil

& small lump coal

(3) Limestone, refuse & crushed stone of which lump sizes are below 50 mm but angular, and

coke

(4) Crude coal, limestone, I refuse & crushed stone of which lump sizes are over 50m/m, and angular

(5) Big lumps with much 1 6 1 specific gravity and an-

gular shape

Cover Rubber Thickness for Heat Resisting Use,

Top Cover (mm) Bottom Cover (mm)

1.5-3


1 case of the heat resisting cover it may be msidered that the cover thickness (particularly of

1.9.2 STEEL CORD BELT

Please refer to our ST BELT catalogue. p cover) is proportional to i t s life. So, thicker bar i s desireable, if the budget allows. 1.10 BREAKER I I case of the oil resisting cover abrasion resistance Efficiency of Neutral Breaker: not required so much in many cases- So, the The neutral breaker is sometimes inserted as

bkness is to be generally about 1.0 mm for both shown below in order to avoid the progress of rp and bottom cover. If the abrasion resistance is rubber cut, which is liable to take place in the guall~ the thickness shall be direction of thickness, when the carrying materials 4 mq-i. are acute.

I k i i e for using Feeder Belt: m belt life is short in case of the short conveyor @m@ Nth like feeder belt. I t is because the time cycle

- Neutral breaker ,$on thereby the cover rubber being damaged dly. In such a case the measures to lengthen the I .-.- 1 kt life by making the cover rubber thicker in

one rank.

Examples of selecting cover rubber thickness and breaker are as shown in the next TABLE. 1.34.

3 Covet Rubber Thickness 8 BreaW

Premise Condition Cover Thickness Nmwt Max. lump Conveyor diameter

' N y h '

length width Bottom m k W (rnrn). hl (mmt

below 100 Ordintq " W W VN-120 4 3 - 4 1.5- 2 - below I@ O~dinary rgjOO NN-2QIO k 5- 6 2- 3 1 NB

50 0rrhar)t 60 450 VN-100 w' 3 2.0- 3.0 1.5 - -I__------

50 Ordinary 50 460 NV- 80 4 5 - 6 2 - 3 INB

urum I diem. 300 ( ( 30 1 7% 1 NV- @O 1 5 1 5 - 7 ( 3 1 IN0

L I f i some instance tihe intermediais breaker, NB ia: not i ~ m d .


r,

HOW T O SELECT BUCKET ELmIATOR BELT

2.1 KIND OF BUCKET ELEVATOR BELT

There are two kinds of bucket elevator belt as shown below.

Continuous Bucket Elevator Centrifugl Dischargts Elevator

-- I

r

2.2 CALCULATION OF TENSION TO BE APPLIED TO BUCKET ELEVATOR BELT

The tension shall be obtained by making the weight calculation as below.

2.21 VERTICAL TYPE BUCKET ELEVATOR BELT

FM = F1 = M + N + Q + S + T Fp = Q + S F2 = M + N + T

FM : Maximum tension applied to elevator belt (kg)

F, : Tight side (loading side) tension of elevator belt (kg)

Fp : Effective tension of elevator belt (kg) F, : Slack side (unloading side) tension of ele-

vator belt (kg) M : % of the total belt weight (kg) N : 1/2 of the total bucket weight (kg) Q : Weight of carrying materials to be loaded a t

the maximum in all the buckets in the loading side (kg)

S : Resistance received by the bucket a t boot pulley (kg)

S = 2. Qt . D v

Qt: Carrying quantity (t lh) D: Boot pulley dia.meter (cm) v: Belt speed (mlmin)

T : % of the weight of boot pulley and takeup (kg) (Consequently, it is not necessary to add the weight, when the boot pulley is of screw fixed type.

2.2.2 SLOPED TYPE BUCKET ELEVATOR BELT

FM = F, = sina (M + N + Q + S + T) Fp = sin& (Q + S) FS = sin& (M + N + T) a : Inclination angle of the line

#

1


2.3 CALCULATION OF REQUIRED POWER 2.4 DETERMINATION OF CARCASS AND NUMBER OF PLY

Kind of carcass, i t s strength and number of ply shall Be determined studying the following factors. 1) Kind of carcass for the condition of use

(carrying material, wet or d r ~ , temperature etc.)

2) Carcass strength and number of ply against maximum tension

3) Maximum number of ply (minimum pulley diameter)

4) Minimum number of ply (efficiency of bolt)

P: Required power for driving pulley (kW)

2.4.1 STUDY FROM THE CONDITION OF USE

Conventionally, cotton fabric has been much used for the bucket elevator belt. Recently, however, vinylon fabric is recommended as the tension member for "YOKOHAMA" Bucket Elevator Belt, because vinylon fabric has high strength and l i t t le elongation meeting with almost al l the conditions of use. So, please design your belt with this standard fabric excepting some very special case.

24.2 STUDY OF CARCASS STRENGTH AGAINST MAXIMUM TENSION

Kind of Carcass Maximum Working Tension

VN-150 7.5 kglamp

VN-200


24.3 STUDY OF MINIMUM PULLEY DIAMETER

<m]

24.4 STUDY OF BOLT EFFICIENCY

The number of carcass ply shall be determined by obtaining the efficiency of bolt E in accordance with the following formula and then determining the kind of carcass and the number of ply from

TABLE 2.3

Type of Continuous Bucket Elevator E=0.7A ( W B + w ~ )

Type of Centrifugal Discharge Elevator E = 0.88FA (WB + WM ) E: Efficiency of bolt A: Distance as shown in the sketch (cm)

Coefficient F Grading

1 .O below 25 rnrn diarn.

1.3 below 50 rnrn diarn.

1.7 below 75 mrn diarn.

Wg :Unit weight of a bucket (kg) WM Weight of carrying material in a bucket (kg) F : Coefficient of carrying material according to ' grading


2.5 METHOD OF SPLICING BUCKET ELEVATOR BELT

There are 3 methods of splicing the belt, viz. by means of lap joint, metal clamp and vulcaniza- 25.2 BY METALIC CLAMPS tion.

1 25.1 LAP JOINT

In general, this method is used for thin belt or for temporarily splicing prior to vulcanization. .The lap length depends upon the kind and width of fabric used for the belt carcass, but it is usually made 2 - 4 times of the bucket spacing.

Unlike the general conveyor belts, it is very difficult to calculate the splicing length of bucket elevator belt. So, this method is convenient. It is used in principle for splicing the light duty belt or thin belt. \

The belt edges are bolted between clamps as sketched. It is necessary to have the width of clamp narrower than the belt width and to round off the corner of the clamp.

25.3 VULCANIZATION

This method is used for the high tension line belt and also when it is necessary to have smooth running and longer belt life. There is such a tendency, however, that the longer the operation time the higher cost is required. When the take-up stroke is insufficient, splicing is temporarily made by lap joint method. Some- times, vulcanization splicing is performed after the initial elongation is eliminated. The method of processing vulcanization splicing is similar to that of general conveyor belts.


Basic Idea for Equipment and Maintenance:

I t is no exageration to say that the life of conveyor belt depends upon the equipments and i t s maintenance and control.

I t is fundamentally necessary to take into consideration of the following questions. 1. Prevention of impact. 2. Prevention of deposit of cake. 3. Prevention of carrying materials from being

trapped (in pulley portion and etc.). 4. Prevention of crokked running. 5. Prevention of abnormal wear a t the skirt,

scraper and chute. 6. Prevention (detection) of longitudinal tear. 7. Detection of carrying materials being block-

aded a t the chute and discharging point. 8. Curvature radius a t the angle transition point

of the line. 9. Distance between trough type rollers and the

pulley, and their disposition. (Transition distance)

10. Prevention of overloading. 11. Disposition of carrier and return rollers. I f the various kinds of machine and equipment always operate properly, the belt will surely keep i ts life longer and the satisfactory performance can be achieved. To perform daily inspection and control of the equipments together with fully equipping so as to satisfy the above stated questions is the key to extend the life of your belt.

3.1 PREVENTION OF IMPACT

(EExi)

There are various causes to damage the belt arlu to invite an accident. Particularly, the chute is the portion where the belt is mostly liable to be damaged. If the construction of the chute is such that a large lump of material directly drops upon the belt from a high place as shown above, cutting and chipping of cover rubber and the fatigue and cutting of carcass cannot be avoided, making the life of belt very short, no matter how good the construction of other parts may be. I t is necessary to select and employ the construc- tions as described below in order to prevent these damages.

I

(a) To ininimize the chute fall I f the distance of fall is long, the construction as shown below shall be employed so as to reduce the impact strength.

1 @ Ladder Chute


@ Feeders When, the feeders as shown below are equipped, impact, wear and cut can be remarkably reduced. The kind of feeder shall be selected in accordance with the nature of carrying material and the condition of installation.

c n ) Belr Feeder

Reciprocating Feeder

Ross Feeder

(b) There are following other methods to reduce impact.

@To install Dead Stock (Stone Box).


2 To hang Curtain.

(3.5)

3 To apply Bar Screen at the end of chu (Finer particles will be firstly put on the b followed by larger lumps.)

(-1 Condition of Material Loading'

Skirt I

(FiGm)

ning Direction of Belt

Skirt shall be equipped in such a manner as a < b or a' < b'.


4 To cut the chute end in V shape. (Finer particles will be loaded first.)

5 To use Pneumatic or 0-pressure Rubber Tures as the cushion rollers. In this case, however, the carrying materials may jump up and be spilled because of their

direction good cushion. SO, it is necessary to apply a Of cover over the upper surface of the chute.

6 To provide Air Spring or ordinary Spring on the cushion roller rack.


3.2 PREVENTION OF DEPOSITE OF CAKE

The abnormal deformation due to the deposit of (-1 sediments of carrying materials (cakes) adversely affects the belt similarly to the trapped materials, which results in damaging carcass. I t is primarily necessary to perfectly clean the belt after unloading the carrying materials so as not to allow the cakes be deposited on the surface of pulley and roller. I t is sometimes difficult, however, to perfectly clean the belt depending upon the condition of loading materials and etc. So, it is necessary to equip an iron scraper to each pulley so that the cakes may not be deposited, even if a little soiled surface of the belt contacts the pulley and the roller. In case of a long span belt there is such a @ m 2 ]

method as to turn over the return belt near the head and ta i l portions so that the unsoiled lower 1 cover rubber may contact the return rollers. The distance required for turning over the belt (which varies depending upon the tension to be applied to the belt a t the point of turning over the belt) is said to be as listed below.

MORDSTEIN Roller Type

Nylon Canvas Belt about 10 times of about 8 times of belt width belt width

about 12.5 times about 10 times ST Belt about 25 times about 20 times

Methods of Cleaning Belt:

(a) Belt Scraper In general, rubber scrapers shall be provided a t , the discharging point as many as possible. I t is not advisable to use old belt, because small pieces of carrying material may be trapped in between canvas plies causing the belt wear.

Single plate type cleaner

Belt &

Single plate type cleaner

(b) Spiral Rubber Roller This is the roller provided with spiral rubber and it is effective for some carrying material.


(c) Washing Type Cleaner

( F ~ Q

Return idler Drain trough

1 Note: This is 8 very effective method, if there is no problem in the disposal of water after washing.

(d) Nylon Brush Cleaning This method is effective when carrying dry powder. I t is advisable to provide a nylon brush 1- in such a manner that the point of i ts hair lightly

[ touches the belt surface. (No good effect can be expected, if the brush is too strongly pushed

Lagainst the belt surface.) It is further necessary to remove the powder trapped between the brush

.hairs in order to le t the belt work properly. (See I Fig. 3.15)

(e) Washing Belt with Nylong Brush This is the combined method of Washing Type Cleaner and Nylon Brush Cleaning, and it is very effective. It is necessary, however, to take into consideration of drainage. (See Fig. 3.16)

Nylon brush belt

Nylon brush plate

+ Drain


3.3 PREVENTION OF CARRYING MATERIAL FROM BEING TRAPPED

When the carrying materials are trapped in -as (-3 shown in Fig. 3.17, it will result in cutting the carcass. So, it should be prevented by all means. According to our experiments and actual results it is found that the carcass is cut, when the lumps of about 30 - 40 mm in size are trapped in while carrying angular rigid material. Generally, it is necessary to equip the systems as shown below, although the actual condition may vary depending upon the limit of each line.

VShaped Scraper (2 - 3 stages) C7

VShaped Scraper

\ Steel Plate Pulley scraper concurrent with Vshaped scraper

\ Rubber

Chute Switch

Steel Plate

Rubber


Deck Plate

Pulley scraper concurrent with V-shaped scraper

U Side Cover (wire net)

Scraper

Prevention' of the materials from being trapped in -4spxferrnedAy-meansafAescraper, V-shaped , scraper, deck plate and wire net pulley cover ( a t

take-up portion etc.) as shown in Figs. 3.18 and

C

(a) Near chute and ta i l pulley The chute is the portion where trapping of carrying materials takes place very of.ten. So, the following arrangements shall be taken to prevent

' the materials from being spilled. To make the trough angle of the belt larger

, particularly a t the chute portion. ( I t is easily done with ST Belt).

. The length of skirt shall be long enough for allowing the materials stabilized. To make the falling distance of the loading materials as short as possible to prevent them from being scattered. . To install the chute in such a manner that the

F loading materials are placed in the center of the belt.

Further, the following arrangements shall be made so that the materials may not be trapped

i n , even i f $hey are spilled. a To install a deck plate under the chute, 3

which length shall be longer than the skirt in about 4 - 5 m. To equip about 2 V-shaped scrapers a t the lower side of the deck plate. To equip a scraper (deflector) concurrent with V-shaped scraper to the tail pulley. To apply wire nets on the side.

By making these arrangements trapping of the materials near the tail can be perfectly prevented.

(b) Near head This portion is liable to cause trapping of the - - - - - - - -

materials next to WCc3iuie,and it is ner:essaryte-- have the following countermeasures.

To provide a chute switch for preventing pile-up and overflow of the materials a t the I discharging chute. ( I f the materials overflow, they will be spilled on the return belt, which \

may cause trapping. To equip 2 or 3 rubber scrapers concurrently with the purpose of cleaning the belt after unloading the materials. To mount 1 or 2 V-shaped scrapers upon the return belt. To apply a deck plate between upper and

I lower belt.

(c) Near drive Maximum tension is applied to the belt before it enters in the driving pulley and if the materials are trapped in near this portion, it is liable to be more badly damaged than in other places. It is, therefore, necessary to have the followong arrangements.

To equip always a scraper to the snubbed pulley.

-c=_ad& plate near the driving portion. -7---------

To apply a wire net at the side. (dl Near take-up I f a pulley cover and further a wire net are applied in addition to the deck plate, when the take-up is positioned immediately behind the driving pulley as shown in Fig. 3.19, trapping of the materials can be prevented in 100%.


3.4 PREVENTION OF CROOKED RUNNING

One of the main causes of the damages of conveyor @-) belt is the damage a t the edge due to crooked running. The methods to correct and prevent the crokked running are as follows.

( 1 ) To use self-aligning idler There are several types of self-aligning idler based upon various principles, each of which is arranged so that the running belt will be slowly .returned back toward the center by means of rotation of the roller, when the belt runs in one direction.

(2) To incline carrying idlers forwardly It is of the same sense as to use crowend pulley so that the belt may always come to the center of the pulley. The carrying idlers can be inclined by filling the liner back-wardly of the supporting stems in both sides. But, if they are inclined too much, the belt will be excwdingty worn out by the rollers. The height of the carrying idlers shall not be changed in more than 3 - 5 mm.

\ Running direction of belt

This position, when the spacer isinserted, is apart from the end of the gauge

Gauge in 35mm.

L Spacer

The position where the belt and carrier contact, The position where the belr contacts the carrier, when the carrier is located properly. when the carrier is inclined.

- T n n i n g diiection of belt 1 Direction of the force to keep the belt in the center.

Position of carrier rollers and gauge

(3) Prevention of crooked running in the return side

It is very effective to use 2-roller idler (1 0"- 15" Trough) in the entire or part of return idlers for providing centering effect.


3.5 PREVENTION OF ABNORMAL WEAR AT THE SKIRT, THE SCRAPER OF THE CHUTE POINT

(FIG. 3.21) Methods of Skirt

Skirt board

Skirt rubber

L Cushion idler

(b) I t is the object of providing the skirt to prevent the materials loaded on the belt from spilling or to properly shape the carrying materials. The size of the skirt should be proper, otherwise an improper skirt will cause spilling of the loaded materials and the abnormal wear of the belt co<er.

(c) It is necessary to have the skirt length in 2 - 4 times of the belt width, viz. usually 1.2 - 1.5 m long, and further to make it longer when carrying larger lumps and with inclination. But, the length may vary depending upon the kind of carrying material, the type of chute and the inclination angle of the belt, and theoretically the length must reach to the belt. Further, it is limited to such a case as to absolutely prevent the materials from spilling out of the belt 4 - that the skirt board is to be mounted throughout , the belt length.

(d) Spacing of the skirt shall be 213 - 314 of the belt width and it is proper to make it narrower

(a) The skirt is provided so as to eliminate the spill when the carrying materials are lumpy. of the loading materials and to stabilize the It must be specially taken care that the skirts are I materials on the belt. But, the carrying perfor- mounted in such a manner that their shapes fan mance may be fully exhibited or on the contrary out in the running direction of the belt. I f they are the belt may be damaged, depending upon the way mounted in narrower relation in the running of installation. I f the pressure against the belt, a t direction, the carrying materials are caught bet- the time of installation, is too strong, irregular ween the belt and the skirt resulting in the damage

) abrasion takes place in the longitudinal direction of of belt. the belt thereby sometimes exposing the carcass. Further, when there is a gap between the belt and the skirt, the carrying materials may be caught in (e) Trapping of the materials can be reciuced by the gap causing premature wear of the belt and making the distance between the skirt and the belt

damaging the belt. in the running direction very close in this side and a little open in the forwarding direction. The distance shall be open in about 2 cm per mtr of the ( m a skirt length.

Running direction Skirt board

Chute

I b Shall be equipped in such a manner as a < b. f

Relation between chute and belt width


3.6 DETECTION OF MATERIAL PILE-UP AT THE CHUTE OR DISCHARGING POINT

I f the chute or discharging portion is piles up with the carrying materials, it is feared that the belt will be badly damaged due to slipping and trapping of the materials. In general, there is such a method as to equip a battledore type limit switch on the upper portion of the chute, which will be operated, when the chute is piled up, and stop the belt.

(FiExzi] Balledore type limit switch

3.7 VERTICAL CURVES I The conveyor line is not always straight but it sometimes rises up from horizontal or becomes horizontal from horizontal or becomes horizontal from inclination. When the line rises up from horizontal, it makes concave curve and the belt will IifGoff the idlers, if the curvature radius is small, thereby causing crooked runnina or saillina of the carrvina mater- 1 " ., - , . ,

ials.

Lift off the idlers at the curve

When the line becomes horizontal-from inclination, it makes convex curve and the belt will be caught between carrying idlers, i f the cukature radius is small, thereby causing ply separation. Consequently, it is necessary to prevent the belt injury by having the curvature radius of larger than the standard value at the transition point and disposing the carrying idlers accordingly.

Liable to cause separation due to buckli


(a) Concave Curve In case of the concave curve the belt may be floated, if the vertical component of a force a t the transition point is larger than the hang tension of the belt due to i ts tare (or belt weight + load weight). So, it is necessary to dispose the carrier rollers with the curvature radius making both of them equal or making the former larger. Further, the belt will be in the utmost floatable condition when it is started with the carrying materials loaded just ahead the transition point. It is required that the tension a t the belt edge shall not be minus. ( I f the tension a t the edge is minus, the edges will be hung down causing the material spill.) I t is necessary to design with the curvature radius larger than obtained in accordance with the following formula.

r = F (Curvature radius with which (W1 . cos a empty. belt will not lift off)

r = F (Curvature radius with (W, + WM ) cos a which loaded belt will

not lift off.)

(b) Convex Curve To the approximately center line of the depth of the trough type belt the tension is applied as it i s a t the portion, to the lower portion less tension is applied, and to the upper portion above the center line much more tension is applied. Cqnsequently, it is necessary, when deermining the radius of curvature, to take into consideration of the two points that the abnormal tension will not be applied to the belt edge and that buckling will not be caused as the result of minus tension a t the center of the belt.

(1) Minimum radius of curvature (MinR) to pre vent the conveyor belt edge from being applied with more than the permissible tension.

(2) Minimum radius of curvature (MinR) to pre G vent buckling with the tension a t the center of the conveyor belt width being maintained in more than

zero.

L

r: Curvature radius (m) F: Tension a t transition point (kg) W, : Belt weight (kg/m) WM : Load weight (kg/m) a: Transition angle

8 : Trough angle Fk: Permissible tension (kglcm)

1 1 General Fabric Belt: BS x- -BS x- 10.5 10 I ST Belt: BS x -BS x-

6.5 6

BS: Breaking Strength (kglcm) Fx: Tension a t transition point (kglcm) b: ~ e l t widtr(m) F, : 1/50 Value of BS E: Carcass modulus (kglcm)

It is necessary to take up the larger value of (1) and (2) obtained.

When it is difficult to have the radius of curvature as calculated, it is necessary to take such countermeasures as to make the trough angle a t the transition point shallow or to adjust the position to mount carrier roller.


3.8 DISTANCE BETWEEN TROUGH TYPE ROLLER AND PULLEY AND THEIR DISPOSITION (TRANSITION DISTANCE)

(1 ) Distance between trough type roller and pulley When the distance (Q), where the belt troughed by the carrying idlers becomes flat, is short, abnormal tension is created locally inside the belt thereby fatigueing the belt carcass in a long run. I t is necessary to take it into consideration particularly with such a line where the tension becomes maximum at the head pulley. (Generally, this type is most popular.)

(2) I t is required to dispose the carrying idlers as shown below in order to minimize the effect upon the belt edge. The above Table shows the values based upon this disposition. I f different, it is necessary to have longer distance.

I (Disposition of idler at head)

The following Table shows the kind of carcass, trough angle and tension to be applied thereto respectively.

Nylon Fabric Belt Vynilon Fabric Belt ST Belt

20 30 35 45 20 30 35 45 20 30 35 45

90 - 100 0.8b 1.3b 1.4b 1.9b 1.lb 1.6b 1.8b 2.6b 1.6b 2.6b 3.lb 4.2b 1 75 -- 90 0.7b 1.2b 1.3b 1.8b 1.0b 1.5b 1.7b 2.4b 1.lb 1.7b 2.0b 2.7b ~

0.7b l . l b 1.2b 1.6b 0.9b 1.4b 1.6b 2.lb 1.0b 1.4b 1.7b 2.3b i

50 -- 75 I

Below 50 0.6b 1.0b I . l b 1.4b 0.8b 1.3b 1.4b 1.8b 1.0b 1.4b 1.7b 2.3b I

Nore: The tension (%) is the rate of tension, to be actually applied at the competent portion, against the standard permissible tension. t


3.9 PREVENTION OF OVERLOADING

When materials are loaded on the belt in more than scheduled carrying quantity, they are liable to be

I spilled, and the tension to be applied to the belt ! becomes much more than scheduled and the predetermined safety factor is reduced. I f it is continued for a long period of time the belt life at the spliced part must be shortened. Consequently, it is necessary to arrange that the quantity of material to be charged does not exceed the scheduled quantity. Usually, the charging quantity shall be restricted by regulating the carrying quantity by means of Merrick's Conveyor before charging the material or making the sectional area of the inlet of the chute fixed. There is such a method as to provide a system to raise an alarm when overloaded.


3.10 DISPOSITION OF CARRIER AND RETURN ROLLERS

In case of a long conveyor system the equipment eost is largely affected by the spacing of carrying idlers. But, if the number of carrying idlers is reduced too much, sag am6unt of the belt is increased thereby increasing the running resistance and the wear of the belt heavily. Trough may not be formed between carrier rollers causing the material spill. The sag amount of the belt is determined in accordance with the following formula and it shall be kept, by experience, within 1 - 2% of the idler spacing. The sag amount is the function of the weight OT

carrying material, belt tare, idler spacing and belt tension, and has the following relation.

The formula for claculating the sag amount between carriers:

6 : Sag amount (mm)

The following calculation will be made assuming that the sag amount (I[) is to be maintained within 1% of the carrier spacing (Qc).

QC T=-(W, +WM)

8 PC (WI + WM) 0.01

QC - 8T

8 1 Incaseof:- - - - Q 100

1 Qc -- - 100- 8T(Wl +WM)

T = - loo 11, (w, +WM)=- loo Q, (W, + -- Qt 8 8 0.06V

v: Belt speed (mlmin) Qt: Capacity (tlh)

WI: Belt tare (kg/m) Disposition of Carrier Roller:

WM : Weight of carrying material (kglm) The belt tension remarkably varies from the head

QC : Carrying idler spaceing (m)- to the tail. Further, it varies depending upon the

F4: Belt tension on the competent part (kg) weight of belt, capacity, and belt speed, but the standard carrier spacing is as listed in the followina Table.

(-1 Standard Carrier Spa~ing (m)

Bulk Density of Carrying Material (tlrn3 ) Belt width (rnrnl Return Roller

0.5 0.8 1 2 1.6 2.6 2.0

300 1.5 1.5 1.5 1.35 1.35 1.35 3.0

450 1.5 1.5 1.5 1.35 1.35 1.2 3.0

600 1.5 1.35 1.35 1.2 1.2 1.2 3.0

750 1.5 1.35 1.2 1.2 1 .O 1 .O 3.0

900 1.35 1 3 5 1.2 1.2 1 .O 1 .O 3.0

1050 1.2 1 2 1 .O 1 .O 1 .Q 1 .O 3.0

1200 1.2 1.2 - 1 .O 1 .O 1 -0 0.9 2.7 -- 3

1500 1.2 1 .o 1 .a 1.0 1 .o 0.9 27. - 3

1700 over 1.2 1 .O 1.0 0.9 0.9 0.9 2.7 -- 3


HOW T O USE CONVEYOR BELT PROPERLY

There are various kinds of trouble, liable to take place while using conveyor belt. I t is the key for accomplishing the belt life to preliminarily find out the trouble, to treat it promptly and to prevent an accident in the bud. The causes inviting .an accident may have been created unawares due to the wear and deterioration of every portions of the belt during i t s long use even with the line seemingly operating satisfac- torily. So, such causes should be found and treated earlier. It is necessary to arrange so that the abnormality can be promptly and accurately found by performing periodical inspection from the beginning of the operation and realizing the suitation of the line and the condition of use. Items for recording the periodical inspection of each conveyor is the date of inspection, name of the inspector, of each conveyor i s the date of inspection, name of the inspector, appearance of the belt (top and bottom cover, edge and spliced part), running condition (croooked running, off- center running, takeup operation status, deposit of cake and trapping of the material) and condition of attached equipments (rotational condition of cushion idlers, carrying idlers and return idlers, attach- ment situation of the skirt rubber and also the condition of cleaner). Further, the phenomenon of the trouble and i t s causes and the cou ntermeasures shall be recorded together.


Phenomenon

1. Belt runs to pne side when it comes to a certain place.

2. A certain portion of the belt maker cro- o ked running throughout the total length of frame.

Causes

A. A part of the conveyor frame is curved.

B. Several idlers in front of the leaned portion are not adjusted properly.

C. Build-up of material on the pulley or idler in the leaning side.

D. Idlers do not rotate well.

E. Head, tail or take-up pulley is distorted.

F. Tripper is distorted.

A. Spliced part is distorted.

B. Belt body is distorted locally.

Countermeasures

A. Inspect the curved portion by stretching a thread. Correct its verticality and horizontality.

B, Adjust the horit~ntality and the perpendicularity against the forwarding direction. If they are not still corrected, incline the roller end in the leaning side toward the forwarding direction. (Inclination angle is less than 2%).

C. Remove the cakes, and inspect and properly treat the cleaner. Equip a cleaner, if it is not equipped yet.

D. Exchange the rollers. Retighten the stud bolt, if it is loose.

E. Adjust each pulley.

F. Correct the distortion, even if it is very slight.

A. Resplice the belt if it scrubs the frame or if the carrying materials spill. (Watch the condition for some time, because it will be corrected gradually).

B. Install self-aligning idler. Adjust ta i l pulley. Exchange the belt locally.

3. Entire belt makes crooked runnhg a- long the totalelength of the frame.

A. Conveyor frame i s distorted.

B. Carrying materials are leaned to one side. Crooked running often takes place when the grading of the materials r e markably varies and large

lumps are contained.

C. Carrier roller or return roller is one-sided1 y lowered.

D. Wind and rain.

E. Carcass is affected by moisture due to the edge damage.

F. Sunshine (If the wn shines upon one side of the f r m , the iron thereof will be abnormally expanded.)

G. Troughability of the belt is inferior.

A. Strengthen the foundation and the frame support. Adjust the frame throughout its length. Such crooked running is liable to take place particularly when the ground base changes.

6: Improve the chute so that the materials may be loaded in the center. Adjust the construction of chute so that larger pieces of material may be placed upon fine particles and the load may be balanced in both sides.

C. ~easure horizontality and perpendicularity of all the idlers and correct the abnormality.

~ : ~ o n s t r u c t a windbreak or improve the belt cover.

E. Investigate the cause of damage and improve the improper part. [Refer to 7.Al

F. Avoid the direct sunshine by applying a cover. Apply coating to deflect the light.

G. Use the belt temporarily until it becomes adapted to the idler, or change the specification.


Phenomenon

4. Injury of top rubber cover

Causes

H. Belt raises up off troughing idler, bowing toward load.

4. Improper direction of the chute.

3. The speed of the load does not conform to the running speed of the belt at the chute.

C. The fall of the chute is too much.

D. The length and the mounting position of the skirt are improper.

E. Belt sag a t the skirt is too much.

F. Build-up of material on the pulley or idler.

3. The chute is piled up with the loading materials.

4. Maintenance of scraper or skirt rubber is improper.

I. The spilled materials are piled up on the return side scrubbing the belt.

1. Cushion idler, or return idler, or carrying idler does not rotate properly.

Countermeasures

H. This is liable to take place when the belt surface is swollen with oil. Remove source of oil, if possible. Select proper oil-resisting belt for Replacement.

A. It is desireable that the falling direction of the material from the chute is similar to the forwarding direction of the belt.

B. I f the both speeds largely differ, the load slips as it is placed upon the belt and it is liable to wear the cover rubber. So, it is desireable to adjust the direction and the speed of the load in conformity with the belt.

C. The impact by lumps of the material shall be alleviated by using a moveable bar and providing a pocket at the chute, providing a feeder belt and minimizing the chute angle.

D. Skirt board shall be widened in the forwarding direction of the belt and making the gap between the belt slightly larger. Equip the skirt board up to the portion where the carrying materials are stabilized on the belt.

E. ~ a k e the spacing of cushion idlers narrower and increase the weight of take-up.

F. Inspect the scraper. Care must be taken to keep the scraper plate in order, as the scraper is liable to cause abnormal wear locally. If there is no scraper yet, it must be equipped.

G. Enlarge the chute portion. Restudy the chute angle. Equip a pile-up detection device.

H. I t is not advisable to use old belt, because fine particles of the carrying material are caught between the fabric. Replace it with the rubber plate for i t s exclusive use.

I. The materials may be spilled due to leaned loading, crooked running, change of ground and improper arrangement of the chute etc. I t is therefore necessary to prevent the respec- tive cause.

J. These idlers shall be periodically adjusted and cleaned. Each of them often causes improper rotation due to the environmental deterioration.


Phenomenon

5. Abnormal wear of the bottom cover rubber

-

8. Injury of the belt carcass

Causes

A. Slip a t the drive pulley.

B. lmproper rotation of idler and self-aligning.

C. Wear due to trapping of fine particles.

D. The effect of the forwardly inclined roller is too much.

E. lmproper curvature radius at .the transition point of the convex curve. l mproper transition distance among pulley and troughing idler.

A. Impact by big lumps at the chute is severe.

B. Trapping of lumps of the carrying material between belt and pulley.

C. Abnormal deformation of the belt locally due to the build-up of material.

D. Safety factor is decreased because the starting time is too short, take-up weight is too heavy or the belt is overloaded.

E. Buckling,

Buckling

F. lmproper transition distance between pulley and through carrier.

G. Belt is caught and torn by the frame due to crooked running.

H. Flexural fatigue of the belt is too heavy because of the small diameter of pulley.

--

Countermeasures

A. Investigate the operation of take-up. Apply rubber lining on the driving pulley. Widen the wrapping angle using snubbed pulley.

B. Similar to 4.5.

C. Inspect the mounting of skirt rubber and cushion idler, and the mounting position of V-shaped cleaner, when the spilled materials are caught in the tail pulley.

D. The forwardly inclined idler serves to prevent crooked running of the belt. But, if it is inclined too much, it is liable to cause abnormal wear. When the abnormal wear is taken place, the inclination angle of the idler shall be reduced.

E. Reinvestigate the convex curve. Enlarge the distance between belt pulley and troughing idler. Change the mounting position of idler. Change into gradually decreasing type trougtiing idler.

A. Take the countermeasure as described in 4.C. Inspect cushion roller. Adjust the environment of the chute.

B. Equip scraper, deck plate and etc.

C. Refer to 4.F. lnspect the abnormal wear of the scraper. It is possible to equip spring type constantly operating scraper and manual type scraper in parallel.

D. It is necessary to restudy the specification of the belt and the conveyor system.

E. Idler shall be changed, because the distance and the spacing of idlers may be sonietimes wide. Reinvestigate the curvature radius of the convex curve.

F. Take the countermeasure 5.E.

G. Take countermeasures to prevent crooked running and off-center running.

H. Replace the pulley with that of standard diameter. It is necessary to restudy the belt specification. Refer to Para. 1.8.


Phenomenon

7. Abnormal injury of belt edge.

8. Separation of the cover stock at the splicbd part:

9. Fabric cut along the step or ply separation at spliced part.

10.Abnormal crooked running of the spliced part only.

Causes

A. The edge portion is distorted due to crooked running or off- center running and torn with fixed spacing.

B. lmproper tripper.

A. lnferior finish of the cover stock portion.

€3. lnferior adhesion.

C. lmproper working 'environment.

A. Lower ply is cut unnecessarily too much.

B. lnferior adhesion.

C. Excessive curtail of the working time.

A. Centering at the time of splicing process is improper or the splicing part is slipped out at the time of processing.

Countermeasures

A. Enlarge the allowance of the frame in the direction of width.

B. Even slight distortion of th6 tripper shall be adjusted, because belt is liable to float from the idler causing off-center running.

A. Buff the overflaw properly.

B. Investigate the material used, vulcanizing press and working procedure, and take proper countermeasures. Repair the part or replace the belt.

C. If the dust flies during the working time making it unable to perform perfect work, necessary countermeasures shall be taken.

A. Resplice.

A. Standard working procedure shall be followed at the time of splicing.


. . SPLICING METHOD A N D REPAIRING METHOD FOR

CONVEYOR BELT -

5.1 MERIT AND DEMERIT OF EACH SPLICING METHOD

Splicing methods o f conveyor bel t are largely divided in to 3 methods, viz. b y means o f metal fasteners, heat vulcanization and self vulcanization. The merit and demerit o f each method are as described below.

Mechanical Splice Heat Vulcanization Self Vulcanization I 1

(1) N o special technique is required.

(2) Can be respliced in a short t ime. (3) Relatively in-expensive.

(1) Shorter l i fe than vulcanization splicing.

(2) Splicing effect (particularly dynamic effect) is lower than tha t o f vulcanization method.

(3) When carrying powder it spills sometimes f r o m the spliced part.

(4) Spliced par t is weak against h o t materials and water permeation.

(5) Liabl t t o damage rollers and pulleys and produce noise.

( 1 ) Spliced par t has strength o f 2 - 3 t imes o f mechanical splice.

(2) Spliced part is smooth providing good eff ic iency t o scraper and skirt.

(3) L i t t l e accident. (4) L i t t l e effect u p o n carcass

when carrying h o t material. (5) Good impact resistance. (6) L i t t l e spil l o f carrying materi-

als. (7) Idlers and pulleys are n o t in-

jured.

( 1 ) Long work ing t ime and skil- lfulness are required, and tools are heavy.

(2) Construct ion cost is relatively high.

(3) Require longer allowance of be l t length f o r splicing.

(1) Easier t o per form than heat vulcanization and n o t many tools are required.

(3) Has similar mert is o f (I), (2), (6 ) . (7) o f heat vulcanization.

( 1 ) Has nearly medium demerits o f ( I ) , (2), (3) o f heat vulcanization and mechanical splice.

(2) Rel iabi l i ty o f the result of work ing is slightly infer ior t o heat vulcanization.


5.2 METAL FASTENERS

The followings are typical ones. 1 ALLIGATOR Lacing This type of fastener has been most popularly used.

(m) - -

2 FLEXCO There is a problem of flexibility in the longitudinal direction. Recently Hinge Type is sold.

Lacing

15 20 25

27 35 45 55

Flexible No. 1 Belt Thickness (mm) I Min. Pulley Diam. (mm)

Belt Thickness (mm)

3 - 4 4- 5 5- 6 6- 7 7- 8 8- 0

10-12

3. NILOS

I This is the fishhook type fastener and has good flexibility in both longitudinal and lateral direc-

. tion. I t has good adaptability to the pulley. Special driving tool is required.

65 12 -- 14 75 14 - 16

1 00 over 16

Nilos Hook No. Belt Thickness (mm)


5.3 SPLICING BY VULCANIZATION

There are two cases of splicing, viz. (1) belts are prespliced in the factory before shipment, and (2) belts are shipped in rolls and they are spliced on the spot bi/ means of an electric heater type portable vulcanization press.

5.3.1 Factory Splicing

Relatively short belts are spliced in the factory and shipped to the user for mounting to his conveyor system. The splicing method does not differ from that of field splicing, but it is required to determine the length of belt ordered carefully.

5.3.2 Field Splicing (Multi-Ply Conveyor Belt)

1. Method of making steps

Kind of Fabric Length of Step (S) (mm)

NV-50, NN-120 NN-100, VN-120 VN- 100,

NN- 500 500 NN- 600 600

Stripping from Top cover side Stripping from Bottom cover side

ey side)

Same as top cover side

Sectional view of the belt of which bath ends are joined together (before vulcanization)

2. Calculation of splicing length (L) L = 0.4b+S (n-1) - 15 (mm) L: Splicing length (mm) b: Belt width (mm) n: Number of ply S: Length of step (mm)


5.3.3 DIMENSION FOR STEEL CORD CONVEYOR BELT

Please refer to our ST BELT catalogue regarding splicing pattern. 1. Method of making steps

1-step overlap method (showing 2 sets)

1. Method of making step

1.1 Singleply

1.2 Two plie

2-step overlap method (showing 1 set)

Step Length (S)

2. Step Length ( S ) Steel Cord Diameter

(mmd

2.0 2.4 2.9 3.3 3.9 4.3 4.6 5.7 6.3 7.1 8.3 9.1

10.0 11.3 12.4

S

(mml

300 300 300 300 350 350 3 50 500 650 700 800 900

1000 1100 1250

3. Calculation of splicing length (L) (mm) Single ply:

L = 0.4b + S Two plies

L = 0.4b + 2s

Kind

UN-150 UN-200 U N-300 UN400 UN-500 UN-600

S (mm)

200

200 300 200 250 300


5.4 SPLICING BY NATURAL VULCANIZATION

This is the method for splicing the belt using self vulcanization material (Trade name of 0-Pack) developed by Yokohama Rubber Co., Ltd.

1. Range of application

Multi-ply Belt

VN, NN-100 UN-200 VN, NN-120 UN-300

2. Method of making steps


Fabric I Step Length (S) I Spline Method

NV-50 VN, NN-100 VN, NN-120

- - - - -

Note: Because tie rubber is not used, the edge portion shall be thickly stripped preliminarily and made flat on the same level with the canvas surface in the next buffing operation.

UN-200 UN-300

3. Calculation of Splicing Length (L) The length required for splicing is calculated in accordance with the following formula.

L=0 .4b+ (n - 1)S+30 The preparation procedure of stripping the belt is similar to that of heat vulcanization process. 1. Classification of materials used and special

feature 1) Bonding of carcass to carcass, rubber to rubber,

and carcass to rubber can be performed using same kind of cement. Namely, there is no difference in bonding edge portion and carcass, and in splicing multi-ply belt and UNICON belt.

2) Tie rubber is not used. 3) Initial adhesion strength is excellent, so it is

possible to use the belt shortly after splicing. 2. Classification of use of Q-Pack 1 ) Primer cement: Q-Pack-A 2) Final coating cement: Q-Pack-B + Q-Pack-C

(10:l) 3. Splicing procedure 1) Firstly align the center so that the splicing part

may not be curved. 2) Mark off the steps. (Refer to Table 5.8

regarding the allowance for steps). 3) Strip off the steps.

(Rubber remained in concave form shall be removed by a knife).

4) Buff the surface previously cut by a knife. It i s not necessary to buff the surface not cut by a knife, for example, stripped surface on which coating is remained.

150 mm

I

(Poor)

Step Splice

200 300

(Good)

Overlap Splice

5) Clean the surface with rubber gasoline or toluole.

Note: Dry the cement until its solvent smell vanishes.

6) Apply the primer cement, Q-Pack-A on the surface to be spliced and dry the cement perfectly. Note: Dry the cement until its solvent smell vanishes.

7) Apply the final coating cement, Q-Pack-B + Q-Pack ( 10: 1) twice and dry it. ~ i t e : Dry the cement un ti/ its fluidity inside the cement dis-

appears. Particularly, the first cementing shall be perfectly dried. I t is desirable to dry the cement perfectly, i f it is within the extent to be able to splice the belt.

8) Affix both ends of the belt together and apply pressure by means of a hand roller or a hammer.

9) Cut through the butt surface by a knife along the dotted line as shown below and make the joint of.cover rubber concave.

~ u t t surface

Butt surface

Note: I. Confirm that there is no gap on the butt surface resulting from the &in t separation.

2. I f there is a slight gap, cut through the surface up to the dotted line as shown above.

3. Take care that the butt joint of the cover rubber is always concave.

10) Apply the primer cement and the final coating over the butt surface thoroughly.


Even when the cover rubber or the carcass of belt is injured due to some cause, it is possible to extend the life of belt, if it is repaired immediately.

5.5.1 Small injury of cover rubber

I t is satisfactory if the environment of the injured portion is buffed and PANGIT is filled in said portion.

5.5.2 Large injury of cover rubber

Strip off the cover rubber only as shown in Fig. 5.7 and repair the part by means of heat vulcanization.

Injured portion ,/'

Knife (Put bias)

5.5.3 SMALL INJURY REACH1 NG CARCASS PLY

5.5.3.1 Fabric belt Cut off the injured plies in step up to the injured portion as shown in Fig. 5.8 and repair the part by inserting new fabric. In such a case concentrated stress i s applied to this portion making the injury grow further. So, it is safe to consider that the belt strengih will be reduced in about 3 times of the width of the injured fabric.

r Cover rubber

- 1st ply

2nd ply

Angle and dimension of carcass fabric

1st ply /F#z I I I I / I

Repair of small injun/ of carcass fabric

L- Canvas ply


5.5.3.2 Steel cord belt Repair the injured portion by means of vulcanization after inserting a new reinforcing cord for each 2 cut-off cords as shown in Fig. 5.7.

Inserted corc

Inserted cord

/

5.5.4 Large injury reaching carcass ply (larger than 113 of the width of belt)

When the strength is lowered down than that of the spliced part, even if the injury was repaired as described 'in 5.5.3.1, the repaired portion shall be removed and spliced again.

5.5.5 Injury of edge

Remove edge rubber of the injured portion as shown in Fig. 5.10 and insert new edge rubber, and then repair it by means of heat vulcanization.

Repair of belt edge


The ideal life of conveyor belt is accomplished when the cover rubber has been worn out uniform- ly and the carcass exposed. I t is seldom, however, that the belt is used in such a manner. There are various factors affecting the belt life, but it is very difficult to estimate them. It is because various factors such as speciality of the conveyor line, elements of the conveyor system, elements of the carrying materials as well as adaptability of the belt, condition of climate, heat, and chemicals, and also the condition of maintenance mixedly affect the life of belt. Mr. Hetzel discloses eridurable carrying quantity in his "Belt Conveyors and Elevators" taking into consideration of the main factors concerning the life of belt. CLL. I.?*

Calculation formu la: Endurable gross carrying quantity = Endurable

carrying quantity x Coefficient of durability rate

(m) Endurable Carrying Quantity

Example of calculation (assuming that the condition of use is to be as follows) Kind of carrying material : Crude coal (inclined-

conveyor) Loading point : 1 point (outdoor) Thickness of top cover. : 6.4 mm, (gravity type

rubber take-u p) Width of belt : 1050 Carrying quantity : 650 t lh Conveyor length : 350 m Driving system : Single head driving Consequently, the following calculation will be made in accordance with Table 6.1.

Endurable carrying quantity = 940 x lo4 ton Endurable gross carrying quantity = 840 x 104 x (c) (dl (bl (a) (d) (dl (dl (dl 1.0 x 1.0 x 1.4 x 1.2 x 0.9 x 1.0 x 1.0 x 1.2 =

=94Ox 104 x 1.81

= 1,700 x lo4 ton Remarks:

(c): Carrying material, (d): Loading point, (b): Top cover thickness, (a): Tensile strength, (d): Inclined conveyor, (dl: Place of installation, (dl: Driving system, (dl: Take-up

If the daily production of coal is assumed to be 5,000 ton, the period of durability will be:- I

T = 'f700 x 104 = 3,400 days = 9.3 years 5,000

Unit: lo4 tons - - - - -

Belt Width Conveyor Length <Center to center distance> (m)


(m) Durability Rates

(a) Tensile Strength of Cover Rubber

Tensile Strength of Cover Rubber ( Kslcm2 )

100 -- 140

180-215

250 -- 285

< --

(d) Durability Rates under Various Conditions

Durability Rate (%I

100

120

140

(b) Thickness of Top Rubber Cover

Operating Condition

Thickness of Top Cover Rubber (mm)

I Durability Rate I%)

Durability Rate (%)

Loading Point 1 I 100

Loading Point 2

Tripper 1

Indoor Installation 1 120

80

80

Inclined Conveyor

Outdoor Installation

With Roof (Outdoor Installation) I 110

90

100

' Single Drive at Head I 100,

Tail or Intermediate Drive

(n) Durability Rate depending "pon Kind of , ,

Carrying Material

Tandem Drive

Screw Type Take-up

Gravity Type Take-up

80

100

120

Kind of Carrying Material

Coal . 4. Large lump

Coal Small lump

Coal Fine

Coke Large lump

Coke Small lump

Coke Hot

Ore -200mm9

Ore - 50mm9

Ore Fine

Rock Large lump

Rock & Gravel Small lump

Clinker Cold

Clinker Hot

Slag

Zinc Slag

Gravel

Cement Cold

Cement Hot

Grains

Salt

Durability Rate (%I

100 - )

120

130

50

60

10

60

80

90

7 0

80

70

20

80

50

90

100

40

200

80


6.2 DIMENSION AND WEIGHT OF BELT PACKAGE

The package of belt at the time of shipment is 6.2.1 DIMENSION AND WEIGHT OF WOODEN DRUM classified as follows depending upon i t s gross PACKAGE weight and dimension.

Calculation formula of drum dimensions: Diameter of Drum:

Remarks: The outside diameter of package shall be within 3.3 times of its width so as to stabilize the package.

L x c = l\j d2 + 0.0785

+ cr Outside Diam. of Package

below 1.8 m diam.

above 1.8m diam.

Simple Package

Wooden Drum Package

D : Drum diameter (cm) d : Core diameter (cm) L : Belt length (m) c : Overall thickness of belt (mm) cr : Lateral piank thickness + allowance

(usually 10- 15cm)

Gross Weight

below 3 ton or

above 3 ton or

Width of Drum:

Width of drum = Width of belt + 25 cm

Gross Weight: G=W1 x L x p WI: Weight of belt (kglm) L : Length of belt (m) p : Coefficient of drum weight only (1.2)

(FIG.)

Grain


6.2.2 DIMENSION AND WEIGHT OF SIMPLE WOODEN DRUM PACKAGE

Steel tape Hessian doth

L x c Package O.D. = 1\1 d2 + 0.0785

+ 5 c m

Width of Package = Width of belt + 1 0 c m

Gross Weight = Wt x L + 30 kg

( ) Relation of Belt Thickness and Belt Length with Reeled Diameter of Belt

balt length (feet)


6.3 VARIOUS TESTING DEVICES

6.3.1 SEPARATION TESTER

Maximum capacity: 50 kg Tolerance: +-2% against specified load Velocity: 25 2 1.5 mmlmin,

50 * 2.5 mmlmin This is used for testing adhesion between fabric plies, rubber layer and fabric ply, and rubber layers.

6.3.2 AMSLER'S TYPE TENS1 LE TESTER

Maximum capacity: 10 ton Variable capacity: 10 ton, 5 ton, 2 ton, 1 ton,

0.5 ton Tolerance: + I % against specified load Velocity: (variable by hand valve)

Max. 150 mmlmin This is used for testing tensile strength and elongation of rubber, cloth and metal, and also for testing compression.


6.3.3 SCHOPPER TENSILE MACHINE

Maximum capacity: 50 kg Variable capacity: 25 kg Tolerance: 2% against specified load Velocity: 200 k 10 mmlmin

300 + 15 mmlmin 500 * 25 mm/min

This machine is used for testing tensile strength and elongation of vulcanized rubber.

capacity: Temperature tolerance in heating tank = 52°C Adjusting range of temperature in heating tank = 2 1°C

This is the machine for simulating the ageing of material by heating the materiaLSlt is further used for the test including the measurement of heat, volume reduction, and moisture content.


6.4. CONVERSION TABLE

6 . 4 . 1 LENGTH

Unit mm cm m in ft Y d mile (stat.) km Mile (Naut.)

mm 1 0.1 0.001 0.03937 0.0032808 0.0010936 6.214x10-' 0.00001 ~~~~~

cm 10 1 0.01 0.3937 0.032808 0.01 0936 6.21 4x1 om6 0.0001

m 1000 100 1 39.37 3.28083 1.0936 6.21 4x1 om4 0.001

~n 25.4 2.54 0.0254 1 0.0833 0.02778 1.578~1 0-5 2.54~1 0-'

ft 304.8 30.48 0.3048 12 1 0.3333 1.894~1 o - ~ 3,084~1 c4 ~d 914.4 91.44 0.9144 36 3 1 5.682x10-~ 9,114~10-~

mile (Stat.) 1609347.0 160934.7 1609.35 63360 5280 1760 1 1.60935 0.869

km I00000 1000 39370 3280.83 1093.6 0.62137 1 0.54

mile (Naut.) 1852000 185200 1852 1.151 1.852 1

6 . 4 . 2 MILLIMETER- Inch

6.4.3 WEIGHT

Kilograms Ounces (Avoir.) Pounds Tons Unit

kg OZ I b Metric Long Short

kg 1 35.274 2.20462 0.001 0.0009842 0.001 102

0 2 0.02835 1 0.06250 2.835~ 1 2.790~ 1 Om' 3.125~ 1

Ib 0.45359 16 1 4.536~ 1 o - ~ 4.464~ 1 o4 0.00050

Metric 1 000 35274 2204.6 1

t Lang 101 6.05 35840 2240 1.12 1 1.01 605

Short 907.1 85 32000 2000 0.9071 9 0.89286 1


6.4.4 WEIGHT PER UNIT LENGTH 6.4.5 DENSITY

I I 1 I I Unit I glcm I kglm 1 Iblin 1 Iblft I Iblyd

glcm

kglm

Iblin

lblft

) 6 .4 .6 POWER

1

10

, I I

178.579

14.8816

Iblyd

6.4.7 PRESSURE

0.10

1

Horsepower

French (metric) 1 English (Japanese)

17.8579

1.48816

4.96054

Unit

g/cm3

kg/m3

Ib/in3

Ib/ft3

0.0056

0.056

kW

1

0.08333

0.49605

kg-'"/sec

Bar

1

0.9807

0.06895

1.0725

1.01 33

glcm

1

0.001

27.6797

0.01602

0.0672

0.671 97

0.201 59

2.01 59.

12

1

0.02788

kglm3

1000

1

27679.7

16.0184

36

3

Kilograms per Sq. Centimeter

(kglcm2

1.01 97

1

0.07031

1.0037

1.0332

0.3333

Long tons per sq. Feet (t/ft2

0.9324

0.9144

0.06429

1

0.9447

Pounds per sq. inch (lb/in2 )

14.50

14.22

1

1 5.56

14.70

Iblin3

0.0361 3

3.613~10-~

1

5.787~10-~ 1

Standard Atmosphere Pressure (760mm)

0.9869

0.9678

0.06805

1.0585

1

Ib/ft3

62.4283

0.06243

1728

1


6.4.8 TRIGONOMETRIC FUNCTIONS OF ANGLES

6.4.9 ANGLE

lu

Note: 180 = n Radian = 3.14 Radian

s ~ n

.2588

.2672

.2756

.2840

-2924

.3007

.3090

.3 173

.3256

.3338

.3420

.3502

.3584

.3665

.3746

.3827

.3907

.3988

.4067

.4 147

.4226

.4305

.4384

.4462

.4540

.4617

.4695

.4772

.4848

.4924

.5000

.5075

COB

.9659

.9636

.96 13

.9588

.9563

.9537

.95 1 4

.9483

.9455

.9426

.9397

.9367

.9336

.9304

.9272

.9239

.9205

.9171

.9 136

.9 100

.go73

.9036

.8908

.8969

.89 10

.8870

.8830

.8788

.8746

.8704

.8660

.8616

Angle

1" 0'

30

2

30

3

30

4

30

5

30

6

30

7

30

8

30

9

30

10

30

1 1

30

12

30

13

30

14

30

Degree

Radians

tan

.2680

.2773

.2868

.2962

.3057

.3153

.3249

.3346

.3443

.3541

.3640

.3739

.3839

.3939

.4040

.4142

.4245

.4348

.4452

.4557

.4663

.4770

-4877

.4986

.5095

.5206

.53 1 7

.5430

.5543

.5658

5774

.5890

sin

.0175

.0262

.0349

.0436

.0523

.0611

.0698

.0785

.0872

.0959

.I045

.I 132

.I219

.I305

.I392

.I 478

.I 564

-1651

.I737

.I822

.I908

.I994

.2079

.2 164

.2250

.2335

.24 1 9

.25M

0"

0

cos

.9999

.9997

.9994

.999 1

.9986

.9981

.9976

,9969

.9962

.9954

.9945

.9936

.9926

.99 14

.9903

.9890

.9877

.9863

.9848

.9833

.98 16

.9799

-9782

.9763

.9744

.9724

.9703

.9682

60"

1.05

30"

0.523

tan

.0175

,0262

.OM9

.0437

.0524

.0612

.0699

.0787

.0875

.0963

.I051

.I139

.I228

.I317

.I405

.I495

1 584

.I 673

.I 763

.I853

.9 144

.2035

.2 126

.22 17

.2309

.240 1

.2493

.2586

90"

1.57

Angle

15"

30'

16

30

17

30

18

30

19

30

20

30

2 1

30

22

30

23

30

24

30

25

30

26

30

27

30

28

30

29

30

30

30

120"

2.10

420"

7.33

180"

3.14

57.35"

1

210"

3.67

1"

0.01745

360"

6.28


6 . 4 . 1 0 VALUES OF e P 8

- Y ;;m - e@

0.10 0.15 0.20 0.25 0.30 0.35

180 1.369 1.602 1.875 2.194 2.5W 3.005

190 1.393 1.644 1.940 2.29 1 2.704 3.191

200 1.418 1.688 2.010 2.393 2.850 3.393

210 1.443 1.733 2.081 2.500 3.002 3.607

220 1.468 1.779 2.1 56 2.61 2 3.165 3.835

230 1.494 1.826 2.232 2.728 3.334 4.084

240 1.520 1.875 2.31 1 2.850 3.514 4.333

1 360 1.875 2.567 3.51 4 4.81 3 6.587 8.958

i--= - 370 1.908 2.635 3.638 5.027 6.942 9.588

380 1.941 2.704 3.768 5.248 7.31 1 10.185

390 1.975 2.776 3.901 5.483 7.705 10.84

400 2.01 0 2.850 4.040 5.727 8.120 11.51

410 2.046 2.925 4.185 5.984 8.558 . 12.25

420 2.081 3.003 4.332 6.250 9.01 3 13.01

430 2.1 18 3.083 4.485 6.528 9.500 13.83

440 2.155 3.165 4.645 6.820 10.01 14.70

450 2.193 3.249 4.81 0 7.126 10.55 15.62

460 2.232 3.335 4.982 7.444 11.12 16.62

470 2.27 1 3.424 5.160 7.777 11.72 17.60

480 2.31 1 3.51 3 5.341 8.1 18 12.34 18.76

6.4.1 1 TEMPERATURE

5 C = (F - 32) x- dJA

6 . 4 . 1 2 SIZE OF FIBER

1) Count (N) : Count shows how many times (768,l m (840yd) a particular yarn is when it weights 1 Ib. (453,6 gr.).

2) Denier (d. Denier) : 3) Conversion of count and denir


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