Yokohama Conveyor Belts

CONVEYOR BELTS TECHNICAL INFORMATION

.c YOKOHAMA CONVEYOR BELTS

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TECHNICAL INFORMATION

11/22/2010

Created by U Thaung Myint

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YOKC)HAMA CONVEYOR EEUS

11/22/2010


Monday

PREFACE CHAPTER 1.1 1.2 1.3 1.4

NAME

........................................................... ... 1 HOW TO SELECT CONVEYOR BELT . . . . . . . . . . . . . . . . . . . . . . . . . ........ OF EACH PART OF CONVEYOR BELT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4 6 6

1.1.1 Drive System . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 1.1.2 Take-up System . . . . . . . . . . . . . . . . . . . . . . . . . . 7 REQUIREMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

SIZE OF CONVEYING MATERIAL & BELT WIDTH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 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 1.5.2 Power for moving loaded material horizontally . . . . . . 14 .m I 1.5.3 Power required for elevating and lowering belt . . . . . . 14 1.5.4 Power required for moveable tripper . . . . . . . . . . . . . 14 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

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CHAPTER 2 2.1 2.2 2.3 2.4

HOW TO SELECT BUCKET ELEVATOR BELT

. . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

KIND OF BUCKET ELEVATOR BELT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .42 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 kElevator et Belt . . . . . . . . . . . . . . 42 CALCULATION OF REQUIRED POWER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43 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 11/22/2010


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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

EQUIPMENT OF CONVEYOR SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 PREVENTION OF IMPACT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 PREVENTION OF DEPOSITE OF CAKE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .50 PREVENTION OF CARRYING MATERIAL FROM BEING TRAPPED . . . . . . . . . . . . . . . .,. . . . . . . . . . . 52 PREVENTION OF CROOKED RUNNING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 PREVENTION OF ABNORMAL WEAR AT THE SKIRT. THE SCRAPER OR THE CHUTE POINT . . . . . . 55 DETECTION OF MATERIAL PILE-UP AT THE CHUTE OR DISCHARGING PQlNT . . . . . . . . . . . . . . . . . . . 56 VERTICAL CURVES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 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 3

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3.1 3.2 3.3 3.4 3.6 3.6 3.7 3.8

CHAPTER 4

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

SPLICING METHOD AND REPAIRING METHOD FOR CONVEYOR BELT . . . . . . . 66 MERIT AND DEMERIT OF EACH SPLICING METHOD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66 SPLICING BY METAL FATENERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67 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 SPLICING BY NATURAL VULCANIZATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70 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 . . . . . . 73 5.5.5 Injury of Edge . . . . . . . . . . . . . . . .

. CHAPTER 5 5.1 5.2 5.3

5.4 5.5

CHAPTER 6 APPENDIX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74 . .&ILIFE EXPECTANCY OF CONVEYOR BELT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .74 '8.2 DIMENSION AND WEIGHT OF BELT PACKAGE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .76 6.2.1 Dimension and Weight of Wooden Drum Package . . . . 76 6.2.2 Dimension and Weight of Simple Wooden Drum Package 77 VARIOUS TESTING DEVICES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78 . 6.3.1 Separation Tester . . . . . . . . . . . . . . . . . . . . . . . . . . 78 6.3.2 AMSLER's Type Tensile Tester . . . . . . . . . . . . . . . . 78 6.3.3 SCHOPPER Tensile Machine . . . . . . . . . . . . . . . . . . 79 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .80 6.4 CONVERSION TABLE . . .

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In order t o 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 Information 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 if 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.

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3. Requirements for Selecting Belt

4. Necessary Properties of Conveyor 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 if 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 maxi' mum tension to be applied t o 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 if 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 if the kind and the construction of the selected belt are suitable for the pqlley diameter and the take-up system.

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 deterioration 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 ) lmpact 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.

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CHAPTER 1

I HOW T O SELECT CONVEYOR BELT

1.1 NAME OF EACH PART OF CONVEYOR BELT

(m)

1.1.1 DRIVE SYSTEM

Although there are different names of drive system, our company takes the following classification. a) Single Drive b) Snubbed Single Drive 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". 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. 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 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)

U

a) b)

S ~ n g l eDrlve

b) Snubbed S ~ n g l eDrive

c ) Tandem T y p e Single Drive

-

dl Tandem ~ y p Drive e

a-

1 e ) f ) Dual Drive

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(a) Screw Type

I

g) h ) Multi-Drive System

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11 (b) Gravity Type

Horizontal Gravity Take-Up

(c) Carriage with Gravity Weight Suspended Type

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1.2 REQUIREMENTS

(KAutomatic ) Tension Controling Type Take-up System (Power Take-up)

@)=

Power Take-up System & Tension Detector

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 (Relation 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

Motor \

Brake

Take-up carriage

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Tension Delector Wire rooe

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SIZE OF CONVEYING MATERIAL & BELT WIDTH

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

Belt Width

)

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In case of uniform lump size

(mm)

Belt Width (mm)

10% of load is maximum lump size

In case of uniform lump size

10% of load is maximum lump size

i

I t

Maximum Lump Size (mm)

Maximum Lump Size (rnm)

350

50

100

1,500

305

505

400

50

125

1,600

330

550

450

75

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

810

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

1.4 CONVEYING MATERIAL & CAPACITY -

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1.4.1 SIZE OF CONVEYING MATERIAL & BELT WIDTH

When the size of conveying material is too large 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. diagonallength of lump

-

,

Q t = 6 0 . A . r - v . . . . . . . . . . . . . . . . . . . . . . . (1) Qt : Conveyor capacity (t/h) A : Loaded cross sectional area of conveying material (m 2 ) ... 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.)

100 150 200 250 300

400

500

1.4.2 CALCULATION FORMULA OF CONVEYOR CA-

PACITY

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. ~

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(-7)

m l . s Troughed ) belt

Flat belt

s Surcharge Angle

~ Value of K3

~

Angle

)

Surcharge Angle

20°

30"

0.0292

0.059 1

0.0906

20

0.0963

0.1245

0.1 538

I0"

Trough Angle

0 (Flat) 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)

Trough Angle

0"

Unit: 10-2rnz 20"

25'

45"

30"

Surcharge Angle \.

\

19"

m0

400

0.28

0.56

450

0.37

0.74

Belt Width (rnm

30"

100

20°

0.86

0.93

1.20

1.13

1.21

1.57

lo0

200

300

1.48

1.07

1.24

1.60

1.94

1.40

1.62

2.09

30

To be safe for design capacity of high speed belt (over 200m/min.), a

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200

300

10"

200

1.20

1.43

1.69

1.43

1.63

1.84

1.57

1.86

2.22

1.86

2.14

2.41

10"

lo0surcharge angle had best be considered.


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300

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1.4.3 CONVEYABLE INCLINATION ANGLE

1.4.4 BULK DENSITY OF MATERIALS

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 37-(

Bulk density of materials

)8- (

Material

Sand

Max. Angle

Cement Coal

Coke Concrete Sand Grain Gravel Lime Wood Ore

Paper Package *Paper Package Macadam

(Powder) (Crude)

22" 16 18"

(Slack)

22" 18 20" . - -- 12 26" 20" 20" 15" 23" 25"

-

-

(Powder) (Chip)

"

I

1 (Crushed) (Mixed)

(Lump) (Powder, rock) (Ordinary) (Dried) Stone Aggregate (Powder) Sulfar (Powder) Salt Sand

* In case of package conveyor belt.

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10" 20"

(Log) (Crushed) (Mixed) (Luma)

16" "25 - 45" 20" 18" 16" 20" 20" 15O 23" 21"

(Dry) (Common) (Wet) (Foundry)

CONVEYABLE INCLINATION ANGLE Material

Bulk Density

Gravel Macadam Limestone Powdered Limestone Clay (Dry) Earth

(Wet) (Common) (Wet)

Mud Cement

(Powder) (Clinker) (Portand Cement)

Concrete Ammonium Sulphate (Dry-Wet) Cinder Coal Crude Lump (Lump) Coke (Dust) Gypsum Quick Lime Grains Soya beam Rice Wheat Sugar Raw Refine Wood (Hardwood) (Softwood) (Hardwood) Woodchip (Softwood) Pulp (Wet) Bark Fuel wood Lumber Sawdust wood AS^ (Dw) (Wet) Ore lron Copper Zink Potash Nickel


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1.4.5 RUNNING SPEED OF BELT

Bulk Density

cific Gravity)

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.

Brass

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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 lndustrial Standards) established in 1965.

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 proportionated to the required power. 1.5.2 POWER FOR MOVING LOADED MATERIAL HORIZONTALLY

1.5.3 POWER REQUIRED LOWERING BELT

FOR

ELEVATING

AND

P : Required power (kW) PI : No load power (kW) P2

: Horizontal load power (kW)

Note:

the lowering belt.

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 t a i l pulleys) (m)

Q, : Corrected value of the center distance (m) 7 : Bulk density of conveying material (t/m3)

h he value becomes negative in case of

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.

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)

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POWER REQUIRED FOR MOVEABLE TRIPPER (Pt) (kW)

--

Kind of Carcass

I f

W1

WI = Belt Weight per mtr. length (kglm)

-

50

0.7

JNN-100 NN-120

100 120

0.8 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

NN-350

350

1.3

NN-400

400

1.4

NN-450

450

1.5

NN-500

500

1.6

NN-600

600

1.7

VN-100

100

1 .O

VN-120

120

1 .O

VN-150

150

1.1

Vinylon Fabric

= 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)

p

Tensile Thickness Strength ( ~ ~ l ~ ~ (mm/P) p )

NV- 50

1.5.5 DATA

(1) Belt Weight (W, ) (kglm) i) The weight o f fabric belt is calculated i n accordance w i t h t h e following formula.

Carcass Designation

= Coefficient depending upon k i n d o f

belt carcass.

ii) I n case o f Steel Cord Conveyor Belt calculation is made i n accordance w i t h the following forrnula. (Please refer t o o u r ST Belt catalogue regarding t h e standard value.) WI = Belt Width ( m ) x Std. Value (kg/m 2 ) ? lncrease 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, althrough there are many other kinds o f roller.

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Idler Diam. (mm)

3-equal-roll Troughing Idler(Kg/set)

400

89.1

6.6

5.0

400

4.5

450

89.1

7.1

5.4

450

7

500

89.1

7.5

5.9

500

7.2

22 24

600

89.1

8.3

6.8

600

9

28

750

114.3

13.2

1 1.6

750

13

42

900

1 14.3

15.1

13.4

900

15.5

49

1050

139.8

21.3

18.9

1050

23

72 .

1200

139.8

23.6

21 .I

1200

26

81

1400

165.2

36.6

32.6

1400

33

112

1600

165.2

41.4

36.6

1600

38

125

1800

165.2

47.4

42.5

1800

46

150

2000

165.2

52.2

46.5

2000

51

160

Belt Width (mm)

Flat Type Return-Idler (Kglset)

(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

Belt Weight WI (Kglm)

Weight of Moving Part W (Kglm)

17 A

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.

: Carrying idler spacing (m)

W'R: QR

Belt Width (mm)

Weight of rotational part per set of return idler (kg)

: Return idler spacing (m)

Wc : Carrying idler weight (kglm)

W R : 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.

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1.6 CALCULATION OF BELT TENSION AND TAKE-UP WEIGHT @bnstructionCharacter of System

w m using idlers with Minary rotational friction mnce, of which installabn is not so good. n using idlers with &cularly little rotational WTm yesistance,of which allatisn condition is

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.

(

calculating braking lowering conveyor

mx of

(322

66

I "." . -

156

n,,

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

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

i:

Output of Electric Motor (kW)

: Slack Side Tension (kg)

Fig. 1.9

: Required power (kW) Efficiency of machine

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1.6.2 SLACK SIDE TENSION

1.6.3 SLOPE TENSION

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

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.

F3 =WIQ1

sina=W,h

.. . . . ...... . . .

FJ : Slope tension while running (kg) 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.

W, : Belt weight (kglm) i?,

: Length of the conveyor slope (m)

a : Angle of inclination (") h : Lift (m)

If assumed to be:1 @e-l=R R: Drive factor

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(12)

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1.6.4 MINIMUM TENSION

1.6.6 MAXIMUM 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"

1.6.6.1

Carrying Side F4 = Return Side

50

8. Rc(= 50

Qt

+ W l1.

. . (13.1 )

.

F4 = 8' 1 1 ~ W1 ......... (13.2)

F,

: Minimum Tension (kg)

R,

: Carrying ldler Spacing (m)

W,

: Belt Weight (kglm)

QR

: Return ldler Spacing (m)

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.

Whichever larger value of (13.1 ) or (13.2) 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. FR = f (W,

+ WR (I1 + Ro) (kg)

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..........

(15)


Monday

"'

Drive a t or near

Elevating Conveyor with Drive at or near Head.

'""

F, + Fp- FR

FM

+

a

@-

T-I

F,

-@

I

or

F4

F M = F ~ ( I R) or

b) Horizontal Conveyor with Drive at or near Tail.

{

FP(I + R)

+ F3+ Fp- F

R

-@

I

+F3+Fp-FR Use the larger one for Fm

d) Elevating Conveyor with Drive at or near Tail.

FpR Or

F,

\-

FM

1

T-

I

F4F a :

+ Fp-

FR

I

-@

I

FP(;:N}

@- F,

FM

+ Fp.

+F4 Use, t h e larger one for Fm

I

F ~ (+R)-FR+F~ I F4 F3 Fp- FR

+ +

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Use the larger one for Fm

Monday

e) Lowering Conveyor with Tail End Drive. [P,

+ P, < P,

Lowering Conveyor with Head End Drive. [PI +P,
(Absolute rate)

(Hold back)

FM{

g)

(Hold back)

+ F3+ F Fp+ F, + F3+F Fp( I + R)

R

or

Use the larger one for FH Use the larger one for Fp

R

FPI( I +R)

f) Lowering Conveyor with Tail End Drive

h) Lowering Conveyor with Head End Drive

IP, +P2 >P, (Absolute rate)

[PI

+ P2 > Pa(Absolute rate)

(No Hold back)

(No Hold back)

@ FPR

I

@ F,+F, I

+FR-FP

+ +

&j~, F3 FR

Use the larger one for Fp

I

Use the larger one for F r

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

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 tail driving portion from the head driving portion. 1.6.7.2 PROCEDURE OF DRIVE SYSTEM

Use the larger o m for Frn

The running resistance on the return side ( F R ) m a y 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 2 belt.

11/22/2010

CALCULATING

MULTI-

(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 tail 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).


Monday

I

1.6.7.3

EXPLANATION OF SYMBOLS OF MULTIDRIVE 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 ~ HHead : effective tension (kg) F P H ~F p ~ 2 : Effective tension of 1st and 2nd head drives F ~ TTail : 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 F1H: Head tight side tension (kg) FIT: Tail tight side tension (kg) F ~ HHead : slack side tension (kg) F ~ TTail : slack side tension (kg) FH1.2 or F 1.2: Tension between Is t and 2nd head drives Wc: Carrying idler roller weight (kglm) F c = f ( W , + W C + W M )(Q+Q,)+-W~h(kg)(16.2) FR .......... Refer t o the formula (15). Qt WM = 0.06.v (kglm) ................ (16.3) - --

WM : Carrying quantity per mtr. (kgJm)

Coefficient of rotational friction of the idler f: h: lift (m) Qt: Carrying quantity (tlh) Q: Horizontal conveyor length (m) Corrected value of the center distance (m) Q : V: Belt speed (mlmin) Required power (s'hafthorsepower) (kw) P:

1.6.7.4

CALCULATION EXAMPLE OF MULTI-DRIVE SYSTEM

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

(1) Obtain the required power. PI = 0.06 x 0.022 x 76.3 x 200 x

+

367

66 =

(2) Obtain the total effective tension (Fp), the return side running resistance ( F R ) and the minimum tension ( F, ). F R = 0.022 x (25 + 6.3) x 5066 = 3,490 kg 6120 x 733.7 = FPH+ FPT= 22,451 kg Fp= 200 Fc = F p - F R = 18,961 kg = 1,875 kg (Sag = 1 %)

; g

Qc = 1.0 m

(3) Motors with the total ~apacityof 1,000 KW shall be installed based upon the total required power of 917 KW as calculated in (1). (4) The following plans are considered for determining the driving position and distributing the motors with the total capacity of 1,000 KW based upon the formula of "Horizontal no load power PI x 0.4 = 278.1 x 0.4 = 120 KWH. Plan 2

Plan 1

Installed motor

drive at

;Iriv:at

ea Tail drive

11/22/2010

51000

'

200kW x 2 Sets

Installed motor 2OOkW x 2 Sets Effective tension F M 8,981 kg Installed motor 200kW x 1 Set Effective tension Fm 4.490 ka


250kW x 2 Sets 1 1,226 kg 250kW x I Set 5,613 kg 250kW x 1 Set 5.61 2 kn

Monday

in the driving positions and the tension at

=0.25,

Tension at each point

Plan 1

1

21.956 ka

.

I

Plan 2

1

22.705 ka

I

I Point A

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

&1=&2=

I

Point B FPHZ Point C

12,975 " 8,980 " 3.995 "

1 1,479 " 5,613 " 5.866 "

Point D

7,485 " 4.490 " 2,995 " 18,961 "

9,356 " 5.61 2 " 3,744 " 18,961 "

Fm Point E Fc

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

.

Whichever larger value of:

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

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Monday

r

I

I CHAPTER 1

]

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

(4) Horizontal Conveyor with Multi-Drive System

1

Or

@ F, +FP-FR-FPHI

Whichever larger value of: F u = F p ~ . R ~ + F P - F R - F ~ :Or:F, +FP-FR-F~

e ~ 022

FP2 =

eP202

-1

Fp (kg). . .

e ~ ~ 1e ~ -

. . . . . . (16.5)

Whichever larger value of:FM= FPT.RT + Fp- F R or F4 + Fp- FR Effective tension distribution of tandem drive system: e ~ 2 8 2- 1 FP (kg) Fp2 = &282eP18~- 1 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.

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Monday

1

t

.& TENSION DISTRIBUTION

.,

OF THE TYPICAL DUAL

DRIVE SYSTEM

' Horizontal

Convevor with Dual Drive at or near


F M= Fp2-&

+F

P

Or F4

1.6.8 TENSION DISTRIBUTION OF THE REVERSIBLE CONVEYOR

1. Operation in reverse direction

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


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

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Monday

1

1.6.9 ACCELERATING RESISTANCE AND ACCELERATING TIME

or F4N b) In case of F M R < F ~ N

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 (17).


FM=FPN( I +R)

or

F, N+FCN

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

50 v(Q+Q,) (W, +-Qt) 3v 206F~

....................... (18)

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 depending upon the take-up position.

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Monday

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

,

..

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

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

Take-up weight = 2Fp- R or 2(F4- FR) rlh~hicheverlarger value)

~rizontalConveyor with Drive a t or near and with take-up system provided middle ~ ~ between d n Head and Tail. 11

-F4 -.FR '

-1

I' I

Take-upweight =2(FpqR+-Fa)

or 2(F4

I -I' -TF~)

(whichever larger value)

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Monday

@5iiii$z) (a) 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

(c) Elevating Conveyor w i t h Drive a t o r near Head and Take-up System provided a t Tail

(b) Elevating Conveyor w i t h Drive a t o r near Head and w i t h Take-up System provid& middle portion between Head and Tail

I n case o f (a): Whichever larger value o f 2FpR o r 2 ( F 4 FR)

+ F3 -

I n case o f (b): F 3 = Wl h F3'= W1 h- Q'

Q

Consequently, the take-up weight shall be whichever larger value of 2 [ F P R

+yr

2 [F~

+y( F R- F B Qr

(F3- FR)]

I n case o f (c): Whichever larger value o f 2(FPR 2F4

11/22/2010


+

I

OT

F R - F3) or

Monday

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

Standard Permissible Tension for Vulcanized Splices

.-0 e belt width is usually used for b Value. More

2m

LL C

>. 0

z 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

SF: FM: b: n: BS:

$4

5

In case of the fibrous tension layer: b x n x B S

c

0 .0 -

Carcass Designation

Pexmissibl~Tension

NV- 50 NN-100 NN--120 NN-150

4.1 kglcm ply 8.3 kglcm ply 10.0 kglcm ply 12.5 kglcm ply

NN-200 NN-250 NN-300 NN-350 NN-400 NN-500 NN-600 VN-100 VN-120 VN-150

16.6 20.8 25.0 29.1 33.3 41.6 50.0 8.3 10.0 12.5

kglcm ply kglcm ply kglcm ply kglcm ply kg/cm ply kglcm ply kglcm ply kglcm ply kglcm ply kglcm ply

. . . . . . . . . . . . .(20)

Safety Factor Maximum tension (kg) Belt width (cm) Number of ply Breaking strength of tension layer (kglcmp)

(b) In case of the steel cords tension layer: FM x SF, .............. (21) b ST - No: Breaking Strength of Steel Cord belt per 1 cm width (kg/cm) FM : Maximum Tension (kg) 1st Safety Factor (Safety factor SF, : against maximum static load). Generally more than 7. ST-NO=

11/22/2010


Monday

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

NV- 50 NN-100

I

1

With these widths and kjnds of canvas there i s no problem as the maximum number of ply.

Maximum Plies for Trw* .Angle of 30°

there is no problem as the maximum number of ply.

-

-

4

5

6

NN-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

NN-500

11/22/2010


Monday

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 t o 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.

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Monday

1.7.3.2 Problem of Impact at the Chute

1.7.3.3 Problem of Load Support

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.

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.

]C-T

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 rectangular or plate like materials are used for the sizes of more than 150 mm.

Weight of Lump (kg) Lump S;re (mm)

Bulk Density (tonlm3

50

75

100

125

150

175

200

225

250

300

350

400

11.5

20

28

42.3

0.5

0.1

0.38

0.85

1.6

2.9

4.0

5.9

8.4

0.8

0.16

0.6

1.4

2.5

4.5

6.4

9.5

13.5

18

32

45

67.5

1 .O

0.2

0.75

1.7

3.1

5.7

7.9

11.8

16.8

23

40

56.5

84.5

1.2

0.24

0.9

2.0

3.7

6.8

9.5

14.2

20.2

28

48

68

101

1.5

0.3

1.1

2.6

4.7

9.6

17.7

25.2

34

60

85

127

2.0

0.4

1.5

3.4

6.3

8.5 11.4

15.9

23.6

33.6

46

79.5

113

169-

2.5

0.5

1.8

4.2

7.9

14.2

19.9

29.5

42

57.5

99.5

141

212-

11/22/2010


Monday

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

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.

11/22/2010


Monday

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

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 v (16-2)

Carrying quantity per mtr. WM :

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

Ordinary Belt

Note: I. Each figure above the oblique line I/)is m e 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.

11/22/2010


Monday

(kglm)

Carrying Quantity (kglm)

Belt Width

Carcass PIy

'1 00 r

120

100 120

1 50

150

I

I

I 90

126 350 over

11/22/2010

90 60

1 54 120

901-1200 1 200 over

128 85

225 177

406 345

up to QOO

1 28

255

112

233

75 225 1 58

1 1 5 0 1

457 316.

90 315 221 126

225 693

38

60

200 1250

15

496 360

QOl"1209 1200 over

1

901-1200 1200 over

900

698 495

1200 over up to 900

504

1260 978

901-1200

315

M3

1200 over


Monday

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 SF Std.

. . . . . . . (23.2)

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 7 p l y 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.

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Monday

(TABLE 1.30) Std. Minimum Pulley Diameter (Head & Drive Pulley)

(unit: (mrn)

No. of Plies Fabric

11/22/2010

\

3P


4P

5P

6P

7P

8P

Monday

1.9 COVER THICKNESS 1.9.1 FABRIC BELT

)1-~(

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.

Cover Rtrbber Thickness for General Use Carrying Material

(1)

Thickness (mm) Top Cover Bottom Cover

Non-abrasive materials such as cereals, chips, cotton, cement & dust coal

(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, refuse & crushed stone of which lump sizes are over 50m/m, and angular

(5)

Big lumps with much specific gravity and angular shape

1.5

1.5

s

2

1.5

3

1.5

I

1

6

1

Cover Rubber Thickness for Heat Resisting Use, Top Cover (mm)

Bottom Cover (mm)

1.5-3

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Monday

1 case

of the heat resisting cover it may be msidered that the cover thickness (particularly of p cover) is proportional to i t s life. So, thicker bar is desireable, if the budget allows. Icase of the oil resisting cover abrasion resistance not required so much in many cases- So, the bkness is to be generally about 1.0 mm for both rp and bottom cover. If the abrasion resistance is guall~ the thickness shall be 4 mq-i.

1.9.2 STEEL CORD BELT

k i i e for using Feeder Belt: m belt life is short in case of the short conveyor Nth like feeder belt. I t is because the time cycle ,$on thereby the cover rubber being damaged dly. In such a case the measures to lengthen the kt life by making the cover rubber thicker in one rank.

@m@

Please refer to our ST BELT catalogue.

I

1.10 BREAKER Efficiency of NeutralBreaker: The neutral breaker is sometimes inserted as shown below in order to avoid the progress of rubber cut, which is liable to take placeinthe direction of thickness, when the carrying materials are acute.

- Neutral breaker I

1

.-.-

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

3

Covet Rubber Thickness 8 BreaW

Ordintq

below I@

O~dinary

"

W

W rgjOO

60

0rrhar)t

'

Bottom (mmt

hl

below 100

50

Cover Thickness

Premise Condition Conveyor ' length width

Max. lump diameter (rnrn).

VN-120

4

NN-2QIO

k

450

VN-100

460

NV- 80

w'

3- 4

Nmwt Nyh m k W

-

1.5- 2

5- 6

2- 3

1 NB

3

2.0- 3.0

1.5

-

4

5- 6

2-3

INB

-I__------

50

I L

Ifi

diem. 300

50

Ordinary

(

urum

(

30

1

7%

1

NV- @O

1

5

1

5- 7

(

3

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

11/22/2010


Monday

1

IN0

I

--r

I

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.

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 F M : 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 elevator 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)

Continuous Bucket Elevator

Centrifugl Dischargts Elevator

S = 2. Q t . D v Qt: Carrying quantity (tlh) 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 i s 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) Inclination angle of the line a:

#

1

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Monday

2.3 CALCULATION OF REQUIRED POWER

P:

Required power for driving pulley (kW)

2.4 DETERMINATION OF NUMBER OF PLY

CARCASS

AND

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) 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 little elongation meeting with almost all 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

VN-150

Maximum Working Tension

7.5 kglamp

VN-200

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Monday

24.3 STUDY OF MINIMUM PULLEY DIAMETER

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

Coefficient F

Grading

1 .O

below 25 rnrn diarn.

1.3

below 50 rnrn diarn.

1.7

below 75 mrn diarn.

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)

Wg :Unit weight of a bucket (kg) WM Weight of carrying material in a bucket (kg) F: Coefficient of carrying material according t o grading '

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Monday

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 vulcanization.

1

25.2

BY METALIC CLAMPS

25.1 LAP JOINT

In general, this method is used for thin belt or for temporarily splicing prior t o 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. Sometimes, vulcanization splicing is performed after the initial elongation is eliminated. The method of processing vulcanization splicing is similar to that of general conveyor belts.

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Monday

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 blockaded 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 t s 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 constructions 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.

@ Ladder Chute

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Monday

1

@ 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 )

Ross Feeder

Belr Feeder

(b) There are following other methods to reduce impact. @ T o install Dead Stock (Stone Box).

Reciprocating Feeder

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Monday

2 To hang Curtain.

3 To apply Bar Screen at the end of chu (Finer particles will be firstly put on the b

(3.5)

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'.

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Monday

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

direction Of

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

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

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Monday

3.2 PREVENTION O F DEPOSITE O F CAKE

1

The abnormal deformation due to the deposit of 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 method as to turn over the return belt near the head and tail portions so that the unsoiled lower 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.

1-(

Single plate type cleaner

Belt

&

Single plate type cleaner

@ m 2 ]

MORDSTEIN Roller Type Nylon Canvas Belt about 10 times of belt width about 12.5 times ST Belt about 25 times

about 8 times of belt width about 10 times about 2 0 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.

(b) Spiral Rubber Roller This is the roller provided with spiral rubber and it is effective for some carrying material. 11/22/2010


Monday

(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 in such a manner that the point of its 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 t o remove the powder trapped between the brush .hairs in order to let the belt work properly. (See Fig. 3.15)

1-

(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)

I

Nylon brush belt Nylon brush plate

+

Drain

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Monday

3.3 PREVENTION OF CARRYING MATERIAL FROM BEING TRAPPED When the carrying materials are trapped in -as 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.

3 (

VShaped Scraper (2

- 3 stages) C7

Chute Switch

VShaped Scraper

\

Steel Plate

Pulley scraper concurrent with Vshaped scraper Rubber

\ Steel Plate

Rubber

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Monday

Deck Plate

Scraper Pulley scraper concurrent with V-shaped scraper

U

,

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

.

11/22/2010

Side Cover (wire net)

(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 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 t o 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%. --------


I

Monday

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.

) -@

\ Running direction of belt This position, when the spacer isinserted, is apart from the end of the gauge in 35mm.

Gauge

(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.

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

-

L Spacer

The position where the belr contacts the carrier, when the carrier is inclined.

1

T n n i n g diiection of belt 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 (10"- 15" Trough) in the entire or part of return idlers for providing centering effect.

11/22/2010


Monday

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

(a) The skirt is provided so as to eliminate the spill of the loading materials and to stabilize the materials on the belt. But, the carrying performance may be fully exhibited or on the contrary the belt may be damaged, depending upon the way of installation. I f the pressure against the belt, a t the time of installation, is too strong, irregular abrasion takes place in the longitudinal direction of 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 the gap causing premature wear of the belt and damaging the belt.

( m a Running direction

(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
(d) Spacing of the skirt shall be 213 - 314 of the belt width and it is proper to make it narrower when the carrying materials are lumpy. It must be specially taken care that the skirts are mounted in such a manner that their shapes fan out in the running direction of the belt. I f they are mounted in narrower relation in the running direction, the carrying materials are caught between the belt and the skirt resulting in the damage of belt.

(e) Trapping of the materials can be reciuced by making the distance between the skirt and 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 skirt length.

Skirt board

Chute

I

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

b

f

Relation between chute and belt width

11/22/2010


Monday

-4

,

I

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.

3.7 VERTICAL CURVES 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 - , . , materials.

Lift off the idlers at the curve

(FiExzi] Balledore type limit switch

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

11/22/2010


Monday

I

1

(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 its 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

(W1 . cos a

(Curvature radius with which empty.belt will not lift off)

F (Curvature radius with r= (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 p r e vent buckling with the tension a t the center of the conveyor belt width being maintained in more than zero.

8:

Fk:

Trough angle Permissible tension (kglcm) 1 1 General Fabric Belt: BS x- -BS x10.5 10 ST Belt: BS x

r: F:

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

BS: Fx: b: F, :

E:

-BS x-

I

6.5 6 Breaking Strength (kglcm) Tension a t transition point (kglcm) ~ e lwt i d t r ( m ) 1/50 Value of BS 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.

11/22/2010


Monday

G

L

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

0.8b

1.3b

1.4b

1.9b

1.lb

1.6b

1.8b

2.6b

1.6b

2.6b

3.lb

4.2b

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

--75

0.7b

l.lb

1.2b

1.6b

0.9b

1.4b

1.6b

2.lb

1.0b

1.4b

1.7b

2.3b

I

0.6b

1.0b

I.lb

1.4b

0.8b

1.3b

1.4b

1.8b

1.0b

1.4b

1.7b

2.3b

I

90

50

- 100

Below 50

1

~

i

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

11/22/2010


Monday

!

3.9 PREVENTION OF OVERLOADING

I

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

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Monday

3.10 DISPOSITION OF CARRIER AND RETURN ROLLERS The following calculation will be made assuming that the sag amount (I[) is to be maintained within 1% of the carrier spacing (Qc).

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.

QC

T=-(W, 8 PC QC

(WI

Incaseof:-

--1

+ WM) 0.01 1 - 8 - Q 100

Qc -

1 0 0 - 8 T ( W l +WM)

T = - loo 11, (w, + W M ) = - loo Q, (W, 8 8

The formula for claculating the sag amount between carriers:

+ --

Qt 0.06V

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

6 : Sag amount (mm)

WI: Belt tare (kg/m) WM : Weight of carrying material (kglm) QC : Carrying idler spaceing (m)F4: Belt tension on the competent part (kg)

1 -(

- 8T

+WM)

Disposition of Carrier Roller: The belt tension remarkably varies from the head to the tail. Further, it varies depending upon the weight of belt, capacity, and belt speed, but the standard carrier spacing is as listed in the followina Table.

Standard Carrier Spa~ing(m)

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

Return Roller

0.5

0.8

12

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

1O .

1 .O

3.0

900

1.35

13 5

1.2

1.2

1.O

1 .O

3.0

1050

1.2

12

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.

1700 over

1.2

1 .O

1.0

0.9

0.9

0.9

2.7 -- 3

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Monday

-

3

HOW T O USE C O N V E Y O R 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 satisfactorily. 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, offcenter 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, attachment situation of the skirt rubber and also the condition of cleaner). Further, the phenomenon of the trouble and i t s causes and the countermeasures shall be recorded together.

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Monday

Causes

Phenomenon

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

2. A certain portion of the belt maker croo ked running throughout the total length of frame.

3. Entire belt makes crooked runnhg a-

Countermeasures

A. A part of the conveyor frame is curved.

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

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

B, Adjust the horit~ntalityand 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. Build-up of material on the pulley or idler in the leaning side.

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

D. Idlers do not rotate well.

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

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

E. Adjust each pulley.

F. Tripper is distorted.

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

A. Spliced part is distorted.

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. Belt body is distorted locally.

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

A. Conveyor frame i s distorted.

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.

long the totalelength of the frame. 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-sided1y lowered.

C. ~easurehorizontality and perpendicularity of all the idlers and correct the abnormality.

D. Wind and rain.

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

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

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

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

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

G. Troughability of the belt is

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

inferior.

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Monday

Phenomenon

Causes

Countermeasures

H. Belt raises up off troughing

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.

idler, bowing toward load.

4. Injury of top rubber cover

the

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

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

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 fall of the chute is too much.

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

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. Belt sag a t the skirt is too

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

4. Improper

direction

of

chute.

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

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

rubber is improper.

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particles of the carrying material are caught between the fabric. Replace it with the rubber plate for i t s exclusive use.

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

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 respective cause.

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

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


Monday

- -

Phenomenon

5. Abnormal wear of

Countermeasures

Causes

A. Slip a t the drive pulley.

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

B. lmproper rotation of idler and self-aligning.

B. Similar to 4.5.

C. Wear due to trapping of fine particles.

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 effect of the forwardly inclined roller is too much.

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

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. Impact by big lumps at the chute is severe.

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

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

B. Equip scraper, deck plate and etc.

C. Abnormal deformation of the

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.

the bottom cover rubber

-

8. Injury of the belt carcass

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.

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

E. Buckling,

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.

Buckling

F. lmproper transition distance

F. Take the countermeasure 5.E.

between pulley and through carrier.

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

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

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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.


Monday

Phenomenon

7. Abnormal injury of belt edge.

Causes

Countermeasures

A. The edge portion is distorted

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

due to crooked running or offcenter running and torn with fixed spacing.

B. Even slight distortion of th6 tripper shall be

B. lmproper tripper.

adjusted, because belt is liable to float from the idler causing off-center running.

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

A. lnferior finish of the cover stock portion.

A. Buff the overflaw properly.

€3. lnferior adhesion.

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

C. lmproper

working

'environ-

ment.

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

A. Lower ply is cut unnecessarily

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

too much.

B. lnferior adhesion. C. Excessive curtail of the working time.

10.Abnormal crooked running of the spliced part only.

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

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


Monday

..

SPLICING METHOD A N D REPAIRING METHOD FOR C O N V E Y O R BELT

-

5.1 MERIT AND DEMERIT OF EACH SPLICING METHOD Splicing methods o f conveyor belt are largely divided i n t o 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

(1)N o special technique is required. (2)Can be respliced in a short time. (3)Relatively in-expensive.

1

(1) Spliced p a r t has strength o f 2 - 3 times o f mechanical splice. (2) Spliced part is smooth providing good efficiency 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 spill o f carrying materials. (7) Idlers and pulleys are n o t injured.

(1)Shorter life than vulcanization

(1) Long working time and skil-

splicing. (2)Splicing effect (particularly dynamic effect) is lower than t h a t o f vulcanization method. (3)When carrying powder it spills sometimes f r o m the spliced part. (4) Spliced part is weak against h o t materials and water permeation. (5)Liablt t o damage rollers and pulleys and produce noise.

lfulness are required, and tools are heavy. (2)Construction cost is relatively high. (3)Require longer allowance of belt length f o r splicing.

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Self Vulcanization

Heat Vulcanization I


(1) Easier t o perform than heat vulcanization and n o t many tools are required. (3) Has similar mertis 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) Reliability o f the result of working is slightly inferior t o heat vulcanization.

Monday

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

(m) -

-

Belt Thickness (mm)

Lacing

3- 4 4- 5 5- 6 6- 7 7- 8 8- 0 10-12 12 -- 14 14 16 over 16

15 20 25

27 35 45 55 65 75 100

-

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

Flexible No.

I .

1

Belt Thickness (mm)

I

Min. Pulley Diam. (mm)

3. NILOS This is the fishhook type fastener and has good flexibility in both longitudinal and lateral direction. I t has good adaptability to the pulley. Special driving tool is required.

Nilos Hook No.

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Belt Thickness (mm)


Monday

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.

Kind of Fabric

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

Length of Step (S) (mm)

NN-120 VN-120

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.

NN- 500 NN- 600

500 600

5.3.2 Field Splicing (Multi-Ply Conveyor Belt) 1. Method of making steps

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)

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Monday

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. Method of making step 1.1 Singleply

1-step overlap method (showing 2 sets)

1.2 Two plie 2-step overlap method (showing 1 set)

Step Length (S)

2. Step Length ( S ) Steel Cord Diameter

S

(mmd

(mml

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

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300 300 300 300 350 350 3 50 500 650 700 800 900 1000 1100 1250

Kind

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

S (mm)

200 200 300 200 250 300

3. Calculation of splicing length (L) (mm) Single ply: L = 0.4b + S Two plies L = 0.4b + 2s


Monday

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.

2. Method of making steps

1. Range of application Multi-ply Belt

VN, NN-100 VN, NN-120

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UN-200 UN-300


Monday

I

Fabric

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

Step Length (S)

150 mm

I

Spline Method

Step Splice I

(Poor)

UN-200 UN-300 -

-

-

200 300 -

Overlap Splice

-

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.

(Good)

5) Clean the surface with rubber gasoline or toluole. Note: Dry the cement until its solvent smell vanishes.

3. Calculation of Splicing Length (L) The length required for splicing is calculated in accordance with the following formula. L = 0 . 4 b + ( 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 t o 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.

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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 eDry : the cement un ti/ its fluidity inside the cement disappears. 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 tsurface t

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.


Monday

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.

5.5.3 SMALL INJURY REACH1NG 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 t o consider that the belt strengih will be reduced in about 3 times of the width of the injured fabric.

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.

r

Cover rubber

- 1st ply 2nd ply

,/'

Injured portion Angle and dimension of carcass fabric

F /#z

1st ply

I

I I I

Knife (Put bias)

/

I

Repair of small injun/ of carcass fabric

L- Canvas ply

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Monday

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

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Monday

The ideal life of conveyor belt is accomplished when the cover rubber has been worn out uniformly 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

Example of calculation (assuming that the condition of use is to be as follows) Kind of carrying material : Crude coal (inclinedconveyor) 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 l h Conveyor length : 350 m : Single head driving Driving system 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

(a)

(bl

(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 = = 9 4 O x 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:-

(m) Endurable Carrying Quantity

T = 'f700 5,000

x 104 = 3,400 days = 9.3 years

-

-

- -

-

Unit: lo4 tons

Conveyor Length (m)

Belt Width

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Monday

I

'

(mDurability ) Rates

(n Durability ) Rate depending "pon ,

Tensile Strength of Cover Rubber

(a)

Tensile Strength of Cover Rubber ( Kslcm2)

Durability Rate

100 -- 140

100

180-215

120

250 -- 285

140

Thickness of Top Cover Rubber

(mm)

I I

Durability Rate I%)

1

Loading Point

2

80

Tripper

1

80

Coal

Small lump

120

Coal

Fine

130

Coke

Large lump

50

Coke

Small lump

60

Coke

Hot

10

Ore

-200mm9

60

Ore

- 50mm9

80

Ore

Fine

90

Rock

Large lump

70

Rock & Gravel

Small lump

80

Clinker

Cold

70

Clinker

Hot

20

100 Slag

80

Zinc Slag

50

100

Gravel

90

90

Outdoor Installation

100

4.

--

Loading Point

Inclined Conveyor

.

Durability Rate

Large lump

Coal

Durability Rates under Various Conditions Operating Condition

Kind of Carrying Material

(%I

Durability Rate (%)

<

(d)

Indoor Installation

1

120

Cement

Cold

100

With Roof (Outdoor Installation)

I

110

Cement

Hot

40

Single Drive at Head

I

100,

Grains

80

80

Screw Type Take-up

100

Gravity Type Take-up

120

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200

Salt

Tail or Intermediate Drive Tandem Drive

Kind of

Carrying Material

Thickness of Top Rubber Cover

(b)

,


Monday

(%I - )

6.2 DIMENSION AND WEIGHT OF BELT PACKAGE The package of belt at the time of shipment is classified as follows depending upon i t s gross weight and dimension. Gross Weight

Outside Diam. of Package

Simple Package

below 3 ton

or

below 1.8 m diam.

Wooden Drum Package

above 3 ton

or

above 1.8m diam.

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

6.2.1 DIMENSION AND WEIGHT OF WOODEN DRUM PACKAGE

Calculation formula of drum dimensions: Diameter of Drum: =

l\j

D d L c

: : : : cr :

d2

+

Lxc 0.0785

+ cr

Drum diameter (cm) Core diameter (cm) Belt length (m) Overall thickness of belt (mm) Lateral piank thickness + allowance (usually 10- 15cm)

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

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Monday

6.2.2 DIMENSION AND WEIGHT OF SIMPLE WOODEN DRUM PACKAGE

Package O.D. =

1\1

d2

+

Lxc +5cm 0.0785

Width of Package = Width of belt + 1 0 c m Gross Weight = Wt x L + 30 k g

Steel tape

(

)

Hessian doth

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

balt length (feet)

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Monday

6.3 VARIOUS TESTING DEVICES 6.3.1 SEPARATION TESTER

6.3.2 AMSLER'S TYPE TENS1LE TESTER

Maximum capacity: Tolerance: Velocity:

Maximum capacity: Variable capacity:

50 kg

+-2%against specified load

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.

11/22/2010

*

10 ton 10 ton, 5 ton, 2 ton, 1 ton, 0.5 ton + I % against specified load Tolerance: 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.


Monday

6.3.3 SCHOPPER TENSILE MACHINE

Maximum capacity: Variable capacity: Tolerance: Velocity:

50 kg 25 kg 2% against specified load 200 k 10 mmlmin 300 + 15 mmlmin 500 25 mm/min This machine is used for testing tensile strength and elongation of vulcanized rubber.

*

11/22/2010

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 materiaLSltis further used for the test including the measurement of heat, volume reduction, and moisture content.


Monday

6.4. CONVERSION TABLE 6 . 4 . 1 LENGTH Unit

mm

cm

1

mm

m

0.1

in

0.001

ft

mile (stat.)

Yd

km

Mile (Naut.)

0.03937 0.0032808 0.0010936 6.214x10-' 0.00001 ~~~~~

cm

10

1

m

1000

100

~n

0.01

0.3937

1

39.37

0.032808 0.01 0936 6.21 4x1om60.0001 3.28083

1.0936

6.21 4x1om4 0.001

0.0833

0.02778

1.578~1 0-5 2.54~1 0-'

25.4

2.54

0.0254

1

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-~

1609347.0 160934.7

mile (Stat.) km mile (Naut.)

1852000

1609.35

63360

5280

1760

1

1.60935

0.869

I00000

1000

39370

3280.83

1093.6

0.62137

1

0.54

185200

1852

1.151

1.852

1

6 . 4 . 2 MILLIMETER- Inch

6.4.3 WEIGHT Unit

kg

t

Kilograms

Ounces (Avoir.)

Pounds

kg

OZ

Ib

1

35.274

02

0.02835

1

Ib

0.45359

16

Tons Metric

Long

Short

2.20462

0.001

0.0009842

0.001102

0.06250

2.835~ 1

2.790~ 1Om'

3.125~ 1

1

4.536~1o

4.464~ 1o4

0.00050

-~

Metric

1000

35274

2204.6

1

Lang

1016.05

35840

2240

1.12

1

1.01 605

32000

2000

0.9071 9

0.89286

1

Short

907.1 85

11/22/2010


Monday

)

6.4.4 WEIGHT PER UNIT LENGTH

I

I

Unit

I glcm

glcm

1

kglm

10

Iblin

I

1 kglm

1

I

1

Iblin

Iblft

Iblyd

Unit

0.201 59

g/cm3

1

kg/m3

0.001

1

Ib/in 3

27.6797

27679.7

1

16.0184

5.787~10-~

0.0056

0.0672

1

0.056

0.671 97 2.01 59. 12

,

glcm

Iblin 3

kglm3

1000

0.03613

Ib/ft 3

62.4283

3.613~10-~ 0.06243

36

14.8816 1.48816 0.08333 1

Iblyd

I

0.10

178.579 17.8579 1

lblft

6.4.5 DENSITY

I

I

I

4.96054 0.49605 0.02788 0.3333

3

Ib/ft 3

1

0.01602

1728 1

6 . 4 . 6 POWER Horsepower French (metric)

1

kW

kg-'"/sec

English (Japanese)

6.4.7 PRESSURE Kilograms per Sq. Centimeter (kglcm2

Pounds per sq. inch (lb/in2 )

Long tons per sq. Feet (t/ft2

Standard Atmosphere Pressure (760mm)

1

1.0197

14.50

0.9324

0.9869

0.9807

1

14.22

0.9144

0.9678

0.06895

0.07031

0.06429

0.06805

1.0725

1.0037

15.56

1

1.0585

1.0133

1.0332

14.70

0.9447

1

Bar

11/22/2010

1


Monday

lu

6.4.8 TRIGONOMETRIC FUNCTIONS O F ANGLES Angle

1"

0' 30

2 30 3 30 4 30 5 30 6 30 7 30 8 30 9 30 10 30

11 30 12 30 13 30 14

.0175

.9999

.0175

.0262

.9997

,0262

.0349

.9994

.OM9

.0436

.9991

.0437

.0523

.9986

.0524

.0611

.9981

.0612

.0698

.9976

.0699

.0785

,9969

.0787

.0872

.9962

.0875

.0959

.9954

.0963

.I045

.9945

.I051

.I132

.9936

.I139

.I219

.9926

.I228

.I305

.9914

.I317

.I392

.9903

.I405

.I 478

.9890

.I495

.I564

.9877

1 584

-1651

.9863

.I673

.I737

.9848

.I763

.I822

.9833

.I853

.I908

.9816

.9144

.I994

.9799

.2035

.2079

-9782

.2126

.2164

.9763

.2217

.2250

.9744

.2309

.2335

.9724

.2401

.241 9

.9703

.2493

.9682

.2586

.25M

30

tan

cos

sin

Angle

15" 30' 16 30 17 30 18 30 19 30 20 30 21 30 22 30 23 30 24 30 25 30 26 30 27 30 28 30 29 30 30 30

s~n

COB

tan

.2588

.9659

.2680

.2672

.9636

.2773

.2756

.9613

.2868

.2840

.9588

.2962

-2924

.9563

.3057

.3007

.9537

.3153

.3090

.951 4

.3249

.3173

.9483

.3346

.3256

.9455

.3443

.3338

.9426

.3541

.3420

.9397

.3640

.3502

.9367

.3739

.3584

.9336

.3839

.3665

.9304

.3939

.3746

.9272

.4040

.3827

.9239

.4142

.3907

.9205

.4245

.3988

.9171

.4348

.4067

.9136

.4452

.4147

.9100

.4557

.4226

.go73

.4663

.4305

.9036

.4770

.4384

.8908

-4877

.4462

.8969

.4986

.4540

.8910

.5095

.4617

.8870

.5206

.4695

.8830

.531 7

.4772

.8788

.5430

.4848

.8746

.5543

.4924

.8704

.5658

.5000

.8660

5774

.5075

.8616

.5890

6.4.9 ANGLE Degree

0"

30"

60"

90"

120"

180"

210"

360"

420"

57.35"

1"

Radians

0

0.523

1.05

1.57

2.10

3.14

3.67

6.28

7.33

1

0.01745

Note:

180 = n Radian = 3.14 Radian

11/22/2010


Monday

6 . 4 . 1 0 VALUES O F e P 8

-Y

1 i--= -

;;m -

e@

0.10

0.15

0.20

0.25

0.30

0.35

180 190

1.369 1.393

1.602

1.875

2.194

2.5W

3.005

1.644

1.940

2.291

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

220 230

1.468 1.494

1.779 1.826

2.1 56 2.232

2.612 2.728

3.165 3.334

3.835 4.084

240

1.520

1.875

2.31 1

2.850

3.514

4.333

360 370

1.875 1.908

2.567 2.635

3.51 4 3.638

4.813 5.027

6.587 6.942

8.958 9.588

380

1.941

2.704

3.768

5.248

7.31 1

10.185

390

1.975

2.776

3.901

7.705

10.84

400 410

2.010 2.046

2.850 2.925

4.040

5.483 5.727

11.51

4.185

420 430

2.081 2.118

3.003 3.083

4.332 4.485

5.984 6.250 6.528

8.120 8.558

440 450 460

2.155 2.193 2.232

3.165

4.645 4.81 0 4.982

6.820 7.126 7.444

470 480

2.27 1 2.31 1

5.160 5.341

7.777 8.1 18

3.249 3.335 3.424 3.513

.

9.013 9.500 10.01

14.70

10.55

15.62

11.12 11.72 12.34

16.62 17.60 18.76

6.4.1 1 TEMPERATURE

C = (F - 32) x- 5

dJA

6 . 4 . 1 2 SIZE O F 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

11/22/2010


12.25 13.01 13.83

Monday

69THE YOKOHAMA RUBBER CO ,LTD MAIN PRODUCTS:

TYRES & TUBES, BELTS, HOSE, SHIP FENDERS, ADHESIVES, INDUSTRIAL-RUBBER PRODUCTS, METALLIC PRODUCTS, AERONAUTICAL & MARINE PRODUCTS, ETC.

HEAD OFFICE:

36-11, SHIMBASHI 5 CHOME, MINATO-KU, TOKYO 105, JAPAN TELEX: J24673 YOKORUCO / C.P.O. Box 1842, TOKYO 100-91, JAPAN.

I -LIAISON REPRESENTATIVES' OFFICES:

I

BE1RUT: DOSSELDORF: LONDON: VANCOUVER: LOS ANGELES: SYDNEY:

I

HOUSTON: --CHICAGO:

P.O. BOX 3611, BE1RUT, LEBANON 4 DOSELDORF, GRAF-ADOL F STRASSE 72, WEST GERMANY BOW BELLS HOUSE, BREAD ST., (CHEAPISIDE) LONDON, E.C.4, ENGLAND 270 SEYMOUR RIVER PLACE, NORTH VANCOUVER B.C., CANADA 1530 CHURCH ROAD MONTEBELLO, CALI FORNIA 90640, U.S.A. P.O. BOX 540 G.P.O. SYDNEY, N.S.W., AUSTRALIA YOKOHAMA TIRE CORPORATION 8042 KATY FREEWAY, HOUSTON, TEXAS 77024, U S A . 12-6 PARKWAY TOWERS 7171, W. GUNNISON ST. HARWOOD HEIGHTS ILL, 60656 U.S.A.

Printed in J q m (RE! 7507) ( 7409SPC

11/22/2010


Monday

11/22/2010


Yokohama Conveyor Belts

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