Yokohama Conveyor Belts

March 16, 2018 | Author: U Thaung Myint | Category: Belt (Mechanical), Powder (Substance), Materials, Mechanical Engineering, Nature
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CONVEYOR BELTS TECHNICAL INFORMATION

.c YOKOHAMA CONVEYOR BELTS

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TECHNICAL INFORMATION

11/22/2010

Created by U Thaung Myint

Monday

YOKC)HAMA CONVEYOR EEUS

11/22/2010

Created by U Thaung Myint

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

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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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SIZE OF CONVEYING MATERIAL & BELT WIDTH

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

Belt Width

)

!

I

I

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)

"

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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.

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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.

11/22/2010

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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)

Created by U Thaung Myint

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"'

Drive a t or near

Elevating Conveyor with Drive at or near Head.

'""

F, + Fp- FR

FM

+

a

@-

T-I

F,

[email protected]

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

[email protected]

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

[email protected]

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

+ +

11/22/2010

Created by U Thaung Myint

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, 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.

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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).

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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

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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

Created by U Thaung Myint

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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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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1

t

.& TENSION DISTRIBUTION

.,

OF THE TYPICAL DUAL

DRIVE SYSTEM

' Horizontal

Convevor with Dual Drive at or near

Whichever larger value of:

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

Whichever larger value of:

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

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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).

Whichever larger value of:

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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(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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@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

Created by U Thaung Myint

+

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=

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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

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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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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

Created by U Thaung Myint

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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

Created by U Thaung Myint

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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

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(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

Created by U Thaung Myint

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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.

11/22/2010

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

(unit: (mrn)

No. of Plies Fabric

11/22/2010

\

3P

Created by U Thaung Myint

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

11/22/2010

Created by U Thaung Myint

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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.

@[email protected]

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 [email protected]

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

Created by U Thaung Myint

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

11/22/2010

Created by U Thaung Myint

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

11/22/2010

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24.3 STUDY OF MINIMUM PULLEY DIAMETER

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