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 |  موضوع: كتاب Belt Conveyors for Bulk Materials السبت 17 نوفمبر 2018, 1:56 pm | |
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Belt Conveyors for Bulk Materials
FIFTH EDITION
Published by the Conveyor Equipment Manufacturers Association
ويتناول الموضوعات الأتية :
List of Figures xiv
List of Tables xxv
Preface xxix
Acknowledgments xxxi
Introduction xxxiii
CHAPTER 1 Belt Conveyor General Applications and Economics 1
Introduction 2
Conveying of a Variety of Materials 2
Wide Range of Capacities 2
Adaptability to Path of Travel 4
Steep Angle Conveying 5
Loading, Discharging, and Stockpiling Capabilities 7
Process Functions 9
Reliability and Availability 10
Environmental Advantages 11
Safety 12
Low Labor Costs 12
Low Power Costs 13
Low Maintenance Costs 13
Long-Distance Transportation 13
High Horsepower, High Tension Conveyors 13
Owning and Operating Costs 14
Present Worth: Required Rate of Return 16
Summary 18
ContentsContents
vi
CHAPTER 2 Design Considerations 19
Conveyor Arrangements 20
Summaries of Chapters 3-14 25
Characteristics and Conveyability of Bulk Materials (Chapter 3) 25
Capacities, Belt Widths, and Speeds (Chapter 4) 25
Belt Conveyor Idlers (Chapter 5) 26
Belt Tension, Power, and Drive Engineering (Chapter 6) 26
Belt Selection (Chapter 7) 26
Pulleys and Shafts (Chapter 8) 27
Vertical Curves (Chapter 9) 27
A Guide to Steep Angle Conveying (Chapter 10) 27
Belt Takeups, Cleaners, and Accessories (Chapter 11) 27
Conveyor Loading and Discharge (Chapter 12) 28
Conveyor Motor Drives and Controls (Chapter 13) 28
Operation, Maintenance, and Safety (Chapter 14) 28
CHAPTER 3 Characteristics and Conveyability of Bulk Materials 29
Material Characteristics 30
Behavior of Materials on a Moving Belt 31
Effect of Inclines and Declines 31
CHAPTER 4 Capacities, Belt Widths, and Speeds 45
Belt Widths 46
Lump Size Considerations 46
Belt Speeds 46
Belt Conveyor Capacities 47
Troughed Belt Load Areas—Standard Edge Distance 49
Flat Belt Load Areas—Standard Edge Distance 51
Belt Conveyor Capacity Tables and Their Use 52
CHAPTER 5 Belt Conveyor Idlers 55
Idler Requirements 56
Idler Classifications 56
General Types of Belt Conveyor Idlers 56
Carrying Idlers 57
Return Idlers 57
Troughing Carrying Idlers 58
Impact Idlers 59
Belt Training Idlers, Carrying 60
Suspended or Garland Idlers 61
Return Idlers 62
Flat Return Idlers 62
Self-Cleaning Return Idlers 62
Return Belt Training Idlers 63
Two-Roll “Vee” Return Idlers 63vii
Contents
Idler Spacing 64
Return Idler Spacing 65
Carrying Idler Spacing at Loading Points 65
Troughing Idler Spacing Adjacent to Terminal Pulleys 65
The Selection of Idlers 67
Rating and Idler Life 67
Idler Selection Procedure 67
Type of Material Handled 68
Lump Size Considerations 68
Idler Load 68
Effect of Load on Predicted Bearing L10 Life 68
Belt Speed 68
Roll Diameter 69
Environmental, Maintenance, and Other Special Conditions 69
Special Conditions 69
Idler Selection Procedure 70
Example Idler Selection 78
Belt Alignment 82
CHAPTER 6 Belt Tension, Power, and Drive Engineering 85
Basic Power Requirements 86
Belt Tension Calculations 87
Compilation of Components of Te 96
Summary of Components of Te 102
CEMA Horsepower Formula 103
Drive Pulley Relationships 104
Wrap Factor, Cw 104
Wrap Factor with Screw Takeup 105
Wrap ? (Arc of Contact) 106
Dual-Pulley Drives 106
Drive Arrangements 109
Maximum and Minimum Belt Tensions 113
Maximum Belt Tension 113
Starting and Stopping Maximum Tension 113
Minimum Belt Tension, Tmin 113
Tension Relationships and Belt Sag Between Idlers 114
Graduated Spacing of Troughing Idlers 114
Analysis of Belt Tensions 117
Belt Tension Examples 127
Belt Tension Calculations 129
Acceleration and Deceleration Forces 136
Belt Stress 136
Vertical Curves 136
Loss of Tension Ratio 136
Load Conditions on the Belt 136
Coasting 136
Takeup Movement 137
Effect on Material Carried 137
Festooning 137
Power Failure 137Contents
viii
Braking Tensions Taken by Return Run and Tail Pulley 137
Analysis of Acceleration and Deceleration Forces 138
Acceleration 138
Deceleration 138
Calculation of Acceleration and Deceleration Forces 138
Design Considerations 139
Necessary Assumptions 140
Calculations 140
Conveyor Horsepower Determination — Graphical Method 141
Determining Required Horsepower —Graphical Method 141
Examples of Belt Tension and Horsepower Calculations — Six Problems 145
Belt Conveyor Drive Equipment 177
Belt Conveyor Drive Location 177
Belt Conveyor Drive Arrangement 177
Speed-Reduction Mechanisms 177
Drive Efficiencies 180
Mechanical Variable Speed Devices 181
Creeper Drives 181
Backstops 182
Determine Need and Capacity of Backstop, Inclined Conveyors 183
Brakes 183
Mechanical Friction Brakes 184
Eddy-Current Brakes 184
Plugging the Motor 185
Dynamic Braking 185
Regenerative Braking 185
Brakes and Backstops in Combination 185
Restraint of Declined Conveyors 185
Backstop and Brake Recommendations 186
Deceleration by Brakes 186
Devices for Acceleration, Deceleration, and Torque Control 186
Starting the Conveyor 186
Controlled Acceleration 187
Brake Requirement Determination (Deceleration Calculations) 189
Material Discharged During Braking Interval 189
Forces Acting During Braking or Deceleration 190
Brake Location 191
Braking Torque 191
Brake Heat Absorption Capacity 191
Brake Calculations 192
CHAPTER 7 Belt Selection 197
Factors in the Composition of Conveyor Belting 199
Conveyor Belt Covers: Characteristics, Composition, and Design 199
General Purpose Belting 200
Special Purpose Belting 201
Cover Considerations 202
Loading Considerations 205
Breakers 206
Molded Edge Belting 206ix
Contents
Cut/Slit Edge Belting 206
Steel Cord Belt Covers 206
The Belt Carcass 207
Carcass Types 207
Textile Reinforcements 208
Steel Reinforcements 211
Vulcanized Splice 213
Mechanically Fastened Splice 214
Belt and System Considerations 215
Elongation 215
Troughability and Load Support 215
Impact Resistance 216
Lump Weight Factor 218
Conveyor Belt Selection 218
Tension Ratings 218
Pulley Face 219
Service Conditions 220
CHAPTER 8 Pulleys and Shafts 225
Conveyor Pulley Assemblies 226
Pulley Types 226
Standard Steel Drum Pulleys 226
Standard Steel Wing Pulleys 228
Advantages of Using ANSI Standards 229
Mine Duty Pulleys 229
Engineered Pulleys 229
Pulley Overloads 233
Pulley Diameters 233
Pulley Face Widths 234
Pulley Crown 235
Pulley Weights 235
Pulley Lagging 235
Thickness and Attachment 235
Lagging Hardness 236
Lagging Grooving 236
High Tension Applications 236
Shafting 236
Shaft Materials 237
Resultant Radial Load 237
Shaft Sizing by Stress Limit 237
Shaft Sizing for Deflection 239
CHAPTER 9 Vertical Curves 241
Concave Vertical Curves 242
Design of Concave Vertical Curves 243
Graphical Construction of Concave Vertical Curve 251
Precautions for the Design of Vertical Concave Curves 252Contents
x
Convex Vertical Curves 252
Design of Convex Vertical Curves 254
Idler Spacing On Convex Curves 255
Use of Bend Pulleys for Convex Curves 258
CHAPTER 10 A Guide to Steep Angle Conveying 259
Incline Limitations with Conventional Conveyors 260
Molded Cleat Belts 261
Large Cleat/Fin Type Belts 268
Pocket Belts 270
Totally Enclosed Belts 273
Sandwich Belts 273
CHAPTER 11 Belt Takeups, Cleaners, and Accessories 279
Belt Takeups 280
Belt Stretch or Elongation 280
Takeup Movement 280
Manual Takeups 281
Automatic Takeups 282
Cleaning Devices 284
Analyzing Carryback 285
Cleaners and Conveyors 286
The Systems Approach to Belt Cleaning 286
Maintaining Cleaning Pressure 288
Belt Cleaners and Horsepower Requirements 288
Belt Cleaners and Top Cover Wear 288
The Importance of Maintenance 289
Specialized Cleaning Systems 289
Handling the Removed Material 291
Belt Turnovers 292
Pulley Wipers 292
Return-Run Belt Cleaning 293
Belt Conveyor Accessory Equipment 295
Weather Protection 295
Spillage Protection: Wing-Type Pulleys 297
Tramp Iron Detectors 297
Conveyor Belt Scales 298
Sampling Devices 298
CHAPTER 12 Conveyor Loading and Discharge 301
Loading the Belt 302
Direction of Loading 302
Transverse Belt Displacement 304
Loading an Inclined Belt Conveyor 304
Impact at Loading Point 304xi
Contents
Loading Chutes and Skirtboards 306
Loading Chutes 306
Skirtboards 308
Feeders 314
Screw Feeders 314
Belt Feeders 315
Drag-Scraper Feeders (Bar Drag Feeders) 315
Apron Feeders 315
Reciprocating Plate Feeders 315
Vibrating Feeders 316
Rotary-Vane Feeders (Pocket Feeders) 316
Rotary-Drum Feeders 316
Rotary-Table Feeders (Disc Feeders) 316
Traveling Rotary-Plow Feeders 317
Feed-Control Gates 317
Methods of Discharging from the Belt 317
Discharge Over-the-End Pulleys 318
Discharge Chutes 318
Lowering Chutes 320
Trippers 321
Stationary (Fixed) Tripper 323
Typical Movable Tripper 323
Tripper Discharge Through Auxiliary Arrangements 324
Plows 325
Plows Discharging to One Side 325
Plows Discharging to Both Sides 326
Discharge Trajectories 326
Calculating and Plotting Normal Material Trajectories 327
Horizontal Belt Conveyor Trajectories 330
Inclined Belt Conveyor Trajectories 332
Declined Belt Conveyor Trajectories 333
Plotting the Trajectory 334
Examples of Trajectories 337
CHAPTER 13 Conveyor Motor Drives and Controls 343
Introduction 344
Conveyor Belt Evaluation Criteria 344
Belt Drive System 344
Electric Motor Attributes 344
Belt Drive Attributes 349
Conveyor Drive Systems Overview 352
AC Induction Motor with Full Voltage Starting and Direct Couplings 353
AC Induction Motor with Reduced Voltage Starting and Direct Coupling 354
Wound Rotor AC Motor and Direct Coupling Drive 356
DC Motor and Direct Coupling 360
AC Induction Motor with Variable Frequency Control and Direct Coupling 364
AC Induction Motor with Full Voltage Starting and Fixed Fill Fluid Coupling 366
AC Induction Motor with Full Voltage Starting and Variable Fill Hydrokinetic Coupling 369
AC Induction Motor and Variable Mechanical Transmission Coupling 369
Other Conveyor Drives 371Contents
xii
Conveyor Belt Controls 372
Drive Type Controller 372
Starting, Running, and Stopping Control Algorithms 372
Belt Protection Controls 373
Belt Control 375
Belt Control Apparatus 376
Conclusion 377
CHAPTER 14 Operation, Maintenance, and Safety 379
Operation 380
Maintenance 380
Safety 383
Guidelines for Safe Operation and Maintenance 384
APPENDIX A Guide for Use of SI (Metric) Units 387
Conversion Factors 388
Example 388
Example 388
Example 388
Metric Practice and Units for Mass, Force, and Weight 390
Mass, Force, and Weight 390
SI (Metric Units) for Belt Conveyor, Belt Tension, and Horsepower Calculations 392
Metric Use of CEMA Belt Tension Formulas 392
Problem 394
Frequently Used Conversion Formulas 396
Comparison of Belt Tensions 397
Comparison of Belt Velocities 397
APPENDIX B Nomenclature 399
APPENDIX C Belt Tension to Rotate Pulleys 405
APPENDIX D Conveyor Installation Standards For Belt Conveyors
Handling Bulk Materials 407
Introduction 408
Conveyor Stringer Alignment 409
Parallel 409
Straightness 409
Squareness 410
Level 410
Pulley and Shaft Alignment 411
Reducer/Motor Base Installation Tolerances 412
Fabricated Structural Bases 412
Concrete Supports 412
Structural Steel Supports 413xiii
Contents
Flexible Coupling Alignment 413
Idler Alignment 415
Belt Alignment 415
Empty Run-in 416
Full Load Run-in 417
Helpful Hints 417
Skirtboard Adjustment 417
Idler Lubrication 418
Manufacturer's Recommendation 418
Type of Lubricant 418
Idler Construction 418xiv
CHAPTER 1 Belt Conveyor General Applications and Economics
Figure 1.1 60-inch conveyor carries large lumps of abrasive ore on incline. 3
Figure 1.2 96-inch conveyor at high-capacity coal-loading facility. 3
Figure 1.3 Regenerative conveyor lowers coal across existing terrain in direct path
from mine. 4
Figure 1.4 Corrugated metal cover over the belt provides weather and
environmental protection. 5
Figure 1.5 Horizontal curve conveyor, conveying following natural terrain. 5
Figure 1.6 Multiple loading stations feed ore to slope conveyor in open-pit mine. 6
Figure 1.7 Rail-mounted hopper with feeder provides loading along full length of
conveyor. 6
Figure 1.8 Multiple feeders in tunnel beneath stockpile provide efficient reclaiming
and blending. 7
Figure 1.9 Material discharging over conveyor head pulley. 7
Figure 1.10 Power-driven twin trippers distributing coal in power plant. 7
Figure 1.11 Double-winged stacker discharging into high-capacity stockpiles on
either side of the feeding conveyor. 8
Figure 1.12 Circular stacker reclaimer simultaneously stacks and reclaims over
3,000,000 cubic feet of wood chips at a major paper mill. 8
Figure 1.13 Shuttle belt conveyors load and trim taconite pellets onto ore vessel on
Great Lakes. 8
Figure 1.14 Self-unloading ship with 78-inch discharge conveyor unloads iron ore
pellets at 10,000 tph. 9
Figure 1.15 Rail-mounted ship unloaders feed 60-inch conveyor system at steel
company. 9
Figure 1.16 V-type plow diverts foundry sand from flat belt conveyor. 9
Figure 1.17 Self-cleaning cross belt magnetic separator. 9
Figure 1.18 Belt scales monitor rate with varying degrees of accuracy to provide both
inventory and process control. 10
List of Figuresxv
List of Figures
Figure 1.19 Multi-stage sampling systems are used in either the in-line or cross belt
configurations to give desired process information on material
specifications. 10
Figure 1.20 Operator controls entire conveyor system from control center with
graphic display panels and push-button console. 11
Figure 1.21 Conveyor in completely enclosed gallery carries its load safely overhead,
avoiding any interference from highway or rail traffic. 11
Figure 1.22 Overland conveyor system utilizing a concrete support structure
provides a pleasing appearance blending with the landscape. 11
Figure 1.23 Tubular galleries provide opportunity to optimize shop assembly of
components. 12
CHAPTER 2 Design Considerations
Figure 2.1 Nomenclature of components of a typical belt conveyor. 20
Figure 2.2 Horizontal belt. 21
Figure 2.3 Horizontal and ascending path, when space will permit vertical curve
and belt strength will permit one belt. 21
Figure 2.4 Ascending and horizontal path, when belt tensions will permit one belt
and space will permit vertical curve. 21
Figure 2.5 Possible horizontal and ascending path, when space will not permit a
vertical curve or when the conveyor belt strength requires two belts. 21
Figure 2.6 Ascending and horizontal path, when advisable to use two conveyor
belts. 21
Figure 2.7 Possible horizontal and ascending path, when space will not permit
vertical curve but belt strength will permit only one belt. 21
Figure 2.8 Compound path with declines, horizontal portions, vertical curves, and
incline. 21
Figure 2.9 Loading can be accomplished, as shown, on minor inclines or declines.
21
Figure 2.10 Traveling loading chute to receive materials at a number of points along
conveyor. 22
Figure 2.11 Discharge over end pulley to form conical pile. 22
Figure 2.12 Discharge by traveling tripper or through the tripper to the storage pile.
See figure 2.14. 22
Figure 2.13 Discharge over either end-pulley of a reversible shuttle belt conveyor. 22
Figure 2.14 Discharge from tripper to one side only, to both sides, or forward again
on conveyor belt. 22
Figure 2.15 Discharge by fixed trippers with or without cross conveyors to fixed piles
or bin openings. 22
Figure 2.16 Discharge by traveling or stationary trippers to ascending cross
conveyors carried by tripper. 22
Figure 2.17 Discharge by hinged plows to one or more fixed locations on one or both
sides of conveyor plows. Device can be adjusted for proportioned
discharge to several places. 22
Figure 2.18 Discharge by traveling or stationary tripper carrying reversible shuttle
belt. 22
Figure 2.19 This overland conveyor following the natural terrain has an undulating
profile with several concave and convex curves. 23List of Figures
xvi
Figure 2.20 Traveling winged stacker with slewing boom stockpiles on both sides of
the feed conveyor. 23
Figure 2.21 Bucket wheel of this combination stacker-reclaimer discharges onto the
stacker boom conveyor, which is reversed for the reclaim operation. 24
Figure 2.22 Bucket wheel reclaimer with wheel at end of boom. 24
Figure 2.23 Crawler-mounted bucket wheel reclaimer with wheel mounted on
chassis discharges onto a rail-mounted reclaim conveyor with slewing
boom. 25
CHAPTER 3 Characteristics and Conveyability of Bulk Materials
Figure 3.1 Discharge over end pulley to form conical pile. 25
CHAPTER 4 Capacities, Belt Widths, and Speeds
Figure 4.1 Belt width necessary for a given lump size. Fines: no grater than 1/10
maximum lump size. 47
Figure 4.2 Area of load cross section. 49
Figure 4.3 Flat belt loading. 51
CHAPTER 5 Belt Conveyor Idlers
Figure 5.1 35° troughing idler. 57
Figure 5.2 Flat belt idler. 57
Figure 5.3 Return belt idler. 57
Figure 5.4 20° troughing idler. 58
Figure 5.5 35° offset troughing idler. 58
Figure 5.6 20° picking belt idler. 59
Figure 5.7 35° troughing rubber-cushion impact idler. 59
Figure 5.8 Flat-belt rubber-cushion impact idler with fixed shaft. 60
Figure 5.9 35° troughed belt training idler. 60
Figure 5.10 Suspended or garland idlers. 61
Figure 5.11 Return belt idler. 62
Figure 5.12 Rubber-disc return idler. 62
Figure 5.13 Helical or spiral self-cleaning return idler. 62
Figure 5.14 Return training idler. 63
Figure 5.15 Two-roll “Vee” return idler, rigid design. 63
Figure 5.16 Two-roll suspended “Vee” return idler. 63
Figure 5.17 K2 = Effect of load on predicted bearing L10 life. 73
Figure 5.18 K3A = Effect of belt speed on predicted bearing L10 life. 73
Figure 5.19 K3B = Effect of roll diameter on predicted bearing L10 life (based on
same belt speed). 74
Figure 5.20 K4A = Effect of maintenance on potential idler life. 75
Figure 5.21 K4B = Effect of environmental conditions of potential idler life. 75
Figure 5.22 K4C = Effect of operating temperature on potential idler life. 75xvii
List of Figures
CHAPTER 6 Belt Tension, Power, and Drive Engineering
Figure 6.1 Variation of temperature correction factor, Kt, with temperature. 89
Figure 6.2 Effect of belt tension on resistance of material to flexure over idler rolls.
94
Figure 6.3 Effective tension required to accelerate material as it is fed onto a belt
conveyor. 99
Figure 6.4 Inclined or horizontal conveyor, pulley driving belt. 104
Figure 6.5 Declined conveyor. Lowering load with regeneration, belt driving
pulley. 104
Figure 6.6 Single-pulley/drive arrangements. 110
Figure 6.6A Single-pulley drive at head end of conveyor without snub pulley. 110
Figure 6.6B Single-pulley drive at head end of conveyor with snub pulley. 110
Figure 6.6C Single-pulley drive at tail end without snub pulley. Used when head end
drive cannot be applied. 110
Figure 6.6D Single-pulley drive at tail end of conveyor without snub pulley;
regenerative. 110
Figure 6.6E Single-pulley drive at tail end of conveyor with snub pulley; regenerative.
110
Figure 6.6F Single-pulley drive at head end of conveyor without snub pulley;
regenerative. 111
Figure 6.6G Single-pulley drive at head end of conveyor with snub pulley;
regenerative. 111
Figure 6.6H Single-pulley drive on return run. 111
Figure 6.6I Single-pulley drive on return run; regenerative. 111
Figure 6.7 Dual-pulley drive arrangements. 112
Figure 6.7A Dual-pulley drive on return run. 112
Figure 6.7B Dual-pulley drive on return run; regenerative. 112
Figure 6.7C Dual-pulley drive on return run; regenerative. 112
Figure 6.7D Dual-pulley drive on return run. Drive pulleys engage clean side of belt.
112
Figure 6.7E Dual-pulley drive with primary drive on tail pulley of conveyor;
regenerative. 112
Figure 6.7F Dual-pulley drive with primary drive on head pulley of conveyor. 112
Figure 6.8 Head pulley drive — horizontal or elevating. 118
Figure 6.8A Inclined conveyor with head pulley drive. 118
Figure 6.8B Horizontal belt conveyor with concave vertical curve, and head pulley
drive. 118
Figure 6.8C Horizontal belt conveyor with convex vertical curve, and head pulley
drive. 118
Figure 6.9 Head pulley drive — lowering without regenerative load. 119
Figure 6.9A Declined belt conveyor with head pulley drive. Lowering without
regenerative load. 119
Figure 6.9B Conveyor with convex vertical curve, head pulley drive. Lowering
without regenerative load. 119
Figure 6.9C Conveyor with concave vertical curve, head pulley drive. Lowering
without regenerative load. 119
Figure 6.10 Head pulley drive — lowering with regenerative load. 120List of Figures
xviii
Figure 6.10A Declined belt conveyor with head pulley drive. Lowering with
regenerative load. 120
Figure 6.10B Conveyor with convex vertical curve, head pulley drive. Lowering with
regenerative load. 120
Figure 6.10C Conveyor with concave vertical curve, head pulley drive. Lowering with
regenerative load. 120
Figure 6.11 Tail pulley drive — horizontal or elevating. 121
Figure 6.11A Inclined conveyor with tail pulley drive. 121
Figure 6.11B Horizontal belt conveyor with concave vertical curve and tail pulley
drive. 121
Figure 6.11C Horizontal belt conveyor with convex vertical curve and tail pulley drive.
121
Figure 6.12 Tail pulley drive — lowering without regenerative load. 122
Figure 6.12A Declined belt conveyor with tail pulley drive. Lowering without
regenerative load. 122
Figure 6.12B Conveyor with convex vertical curve, tail pulley drive. Lowering without
regenerative load. 122
Figure 6.12C Conveyor with concave vertical curve, tail pulley drive. Lowering
without regenerative load. 122
Figure 6.13 Tail pulley drive — lowering with regenerative load. 123
Figure 6.13A Declined belt conveyor with tail pulley drive. Lowering with regenerative
load. 123
Figure 6.13B Conveyor with concave vertical curve, tail pulley drive. Lowering with
regenerative load. 123
Figure 6.13C Conveyor with convex vertical curve, tail pulley drive. Lowering with
regenerative load. 123
Figure 6.14 Drive on return run — horizontal or elevating. 124
Figure 6.14A Inclined conveyor with drive on return run. 124
Figure 6.14B Horizontal belt conveyor with concave vertical curve, and drive on return
run. 124
Figure 6.14C Horizontal belt conveyor with convex vertical curve, and drive on return
run. 124
Figure 6.15 Drive on return run — lowering without regenerative load. 125
Figure 6.15A Declined conveyor, with drive on return run. Lowering without
regenerative load. 125
Figure 6.15B Conveyor with convex vertical curve, drive on return run. Lowering
without regenerative load. 125
Figure 6.15C Conveyor with concave vertical curve, drive on return run. Lowering
without regenerative load. 125
Figure 6.16 Drive on return run — lowering with regenerative load. 126
Figure 6.16A Declined conveyor with drive on return run. Lowering with regenerative
load. 126
Figure 6.16B Conveyor with concave vertical curve, drive on return run. Lowering
with regenerative load. 126
Figure 6.16C Conveyor with convex vertical curve, drive on return run. Lowering with
regenerative load. 126
Figure 6.17 Horsepower required to drive empty conveyor. 142
Figure 6.18 Horsepower required to elevate material. 143
Figure 6.19 Horsepower required to convey material horizontally. 144xix
List of Figures
Figure 6.20 Inclined belt conveyor. 145
Figure 6.21 Declined belt conveyor. 148
Figure 6.22 Horizontal belt conveyor. 153
Figure 6.23 Complex belt line. 161
Figure 6.24 Belt conveyor with concave vertical curve. 173
Figure 6.25 Belt conveyor with convex vertical curve. 173
Figure 6.26 Gear motor is directly connected, by a flexible coupling, to the motor’s
drive shaft. 177
Figure 6.27 Gear motor combined with chain drive or synchronous belt drive to
drive shaft. 178
Figure 6.28 Parallel-shaft speed reducer directly coupled to the motor and to drive
shaft. 178
Figure 6.29 Parallel-shaft speed reducer coupled to motor, and with chain drive, to
drive shaft. 178
Figure 6.30 Spiral-bevel helical speed reducer, helical-worm speed reducer, or
worm-gear speed reducer, directly coupled to motor and to drive shaft.
179
Figure 6.31 Spiral-bevel helical speed reducer, helical-worm speed reducer, or
worm-gear speed reducer, coupled to motor and, with chain drive to
drive. 179
Figure 6.32 Drive-shaft-mounted speed reducer with direct drive of V-belt reduction
from reducer mounted motor. 179
Figure 6.33 Two motors (dual-pulley drive) coupled to helical or herringbone gear
speed reducers, directly coupled to drive shafts. 180
Figure 6.34 Typical differential band brake backstop. 182
Figure 6.35 Sprag type holdback. 182
Figure 6.36 Over-running clutch backstop. 182
CHAPTER 7 Belt Selection
Figure 7.1 Cross section of a fabric-reinforced belt (Cut/slit edge). 199
Figure 7.2 Protecting steel cords with rubber. 206
Figure 7.3 Plain weave. 209
Figure 7.4 Broken twill/crowfoot. 209
Figure 7.5 Basket or oxford weave. 209
Figure 7.6 Leno weave. 209
Figure 7.7 Woven cord. 210
Figure 7.8 Solid woven fabric. 210
Figure 7.9 Straight warp fabric. 211
Figure 7.10 All-gum steel cord belt. 212
Figure 7.11 Fabric-reinforced steel cord belt. 212
Figure 7.12 Vulcanized fabric belt splice. 213
Figure 7.13 Steel-cable belt splice. 214
Figure 7.14 Hinged-plate type of mechanical splice. 214
Figure 7.15 Belt troughing in-line idler. 215
Figure 7.16 Equivalent free fall and location of values Hf and Hr. 218List of Figures
xx
CHAPTER 8 Pulleys and Shafts
Figure 8.1 Typical welded steel pulley. 227
Figure 8.2 Fabricated curve crown pulley. 227
Figure 8.3 Spun-end curve crown pulley. 227
Figure 8.4 Lagged welded steel pulley. 227
Figure 8.5 Welded steel pulley with grooved lagging. 227
Figure 8.6 Slide-lagged pulley. 227
Figure 8.7 Lagged wing pulley. 227
Figure 8.8 Fabricated wing type pulley. 227
Figure 8.9 Graphical means of obtaining resultant radial load. 237
Figure 8.10 Shaft deflection. 240
CHAPTER 9 Vertical Curves
Figure 9.1 Concave vertical curve. 242
Figure 9.2 Profile of conveyor with concave vertical curve. 243
Figure 9.3 Recommended minimum radii for concave vertical belt conveyor curves.
244
Figure 9.4 Length X for concave vertical curves. 248
Figure 9.5 Profile of concave vertical curve. 248
Figure 9.6 Method of plotting vertical curves. 252
Figure 9.7 Convex vertical curve. 252
CHAPTER 10 A Guide to Steep Angle Conveying
Figure 10.1 Example of molded chevron cleated belt. 260
Figure 10.2 Example of molded “U”-shaped cleat belt. 261
Figure 10.3 Large cleat/fin belt illustration. 269
Figure 10.4 Example of pocket belt partitions. 270
Figure 10.5 Typical pocket belt for vertical elevating. 270
Figure 10.6 Typical return support for pocket belt. 271
Figure 10.7 Illustrated method of calculating pocket belt capacity. 271
Figure 10.8 Pocket belt twisted about its vertical axis. 272
Figure 10.9 Typical sandwich belt cross section. 273
Figure 10.10 Available sandwich belt profiles. 275
Figure 10.11 C-profile sandwich belt feeding a bin. 275
Figure 10.12 C-profile sandwich belt on board a self-unloading ship. 276
Figure 10.13 Typical sandwich belt elevator components. 276
Figure 10.14 L-profile sandwich belt with spring loaded pressure rolls. 277
Figure 10.15 Sandwich belt in an open pit mining application. 277xxi
List of Figures
CHAPTER 11 Belt Takeups, Cleaners, and Accessories
Figure 11.1 Manually adjusted screw takeup assembly. 281
Figure 11.2 Horizontal automatic gravity takeup. Counterweight and cables not
shown. 282
Figure 11.3 Vertical automatic gravity takeup on an inclined conveyor. 282
Figure 11.4 Multiple belt cleaner system. 286
Figure 11.5 Cleaning angles. 287
Figure 11.6 Rotary brush cleaner. 289
Figure 11.7 Pneumatic belt cleaner. 289
Figure 11.8 Belt washing stations. 290
Figure 11.9 Vibrating scavenger conveyor to return fines removed by secondary
cleaners to main material flow. 291
Figure 11.10 Belt turnover scheme. 292
Figure 11.11 Snub pulley wiper. 293
Figure 11.12 Three typical styles of belt conveyor decking. 293
Figure 11.13 V-plow return-belt scraper. 294
Figure 11.14 Diagonal plow return belt scraper. 294
Figure 11.15 Half covers over conveyor belt. 295
Figure 11.16 Three-quarter covers over conveyor belt. 296
Figure 11.17 Wind break on belt conveyor. 296
Figure 11.18 Example of wind hoops on a belt conveyor. 296
Figure 11.19 Spiral-wrapped wing-type pulley. 297
Figure 11.20 Typical electronic load cell type of belt scale. 298
Figure 11.21 Typical sampling arrangement. 299
CHAPTER 12 Conveyor Loading and Discharge
Figure 12.1 Speed-up belt conveyor. 303
Figure 12.2 Typical loading chute. 305
Figure 12.3 Grizzly or screened loading chute (after Hetzel.) 305
Figure 12.4 Notched or wedge shaped loading opening. 305
Figure 12.5 Stone box loading chute. 307
Figure 12.6 Tailbox. 308
Figure 12.7 Deflector or straight chute liner patterns. 309
Figure 12.8 Typical application of skirtboard on troughed belt. 309
Figure 12.9 Continuous skirtboards on a flat belt. 309
Figure 12.10 Skirtboards on a troughed belt. 310
Figure 12.11 Screw feeder. 314
Figure 12.12 Typical belt feeder. 314
Figure 12.13 Typical drag scraper feeder. 315
Figure 12.14 Apron feeder. 315
Figure 12.15 Single-plate feeder. 315
Figure 12.16 Typical electrical vibrating feeder. 316
Figure 12.17 Typical vane or pocket feeder. 316
Figure 12.18 Rotary drum feeder. 316
Figure 12.19 Rotary-table feeder. 316List of Figures
xxii
Figure 12.20 Traveling rotary plow. 317
Figure 12.21 Typical regulating gate feeder. 317
Figure 12.22 Tunnel gate. 317
Figure 12.23 Discharge over-the-end pulley. 318
Figure 12.24 Typical simple discharge chute. 319
Figure 12.25 Spiral lowering chute. 320
Figure 12.26 Bin lowering chute. 320
Figure 12.27 “Rock ladder” lowering chute. 321
Figure 12.28 Telescopic chute. 321
Figure 12.29 Typical motor-driven belt conveyor tripper. 322
Figure 12.30 Stationary trippers. 322
Figure 12.31 Movable tripper. 322
Figure 12.32 Two typical movable trippers. 323
Figure 12.33 Movable tripper with reversible cross belt. 324
Figure 12.34 Typical tripper with two transverse stacker belts. 324
Figure 12.35 Typical movable tripper with reversible shuttle belt. 324
Figure 12.36 Horizontal swing plow. 325
Figure 12.37 Single lift plow. 325
Figure 12.38 Horizontal V-plow. 325
Figure 12.39 Vertical V-plow. 325
Figure 12.40 Proportioning V-plow. 325
Figure 12.41 Traveling V-plow. 325
Figure 12.42 Area of circular segment is equal to the cross-sectional area of the
material load on the normal troughed portion of the conveyor belt. 328
Figure 12.43 To determine the center of gravity of the cross-section of the load on a
flat belt, refer to Table 12-2 for values of a1 and h. 328
Figure 12.44 When the belt speed is sufficiently high, the material leaves the belt at the
point of tangency of the belt with the pulley. 331
Figure 12.45 When the belt speed is not high enough, the material will follow part way
around the conveyor. 331
Figure 12.46 When, in an inclined conveyor, the tangential speed is high (see text), the
material will leave the belt at the point of tangency of the belt and pulley.
332
Figure 12.47 When, in an inclined conveyor, the tangential velocity is equal to a
specific value (see text), the material will leave the belt at the top of the
end pulley. 332
Figure 12.48 When, in an inclined conveyor, the tangential velocity is low (see text),
the material will follow part way around the end pulley. 333
Figure 12.49 When, in a declined conveyor, the tangential velocity is high (see text),
the material will leave the belt at the point of tangency of the belt and
pulley. 333
Figure 12.50 When, in a declined conveyor, the tangential velocity is low (see text), the
material will follow part way around the end pulley. 334
Figure 12.51 Trajectory formed as material is discharged over the end pulley of an
horizontal troughed belt conveyor. 337
Figure 12.52 Sized aggregate pours over end pulley of this inclined conveyor. 338
Figure 12.53 Iron-ore pellets discharging from boom belt of Great Lakes self-unloader
ship at 10,000 tph. 338xxiii
List of Figures
Figure 12.54 Close-up of trajectory from head pulley of conveyor, speed 760 fpm,
handling iron-ore pellets. 338
Figure 12.55 Example of discharge trajectory: Drawing No. 1. 339
Figure 12.56 Example of discharge trajectory: Drawing No. 2. 340
Figure 12.57 Example of discharge trajectory: Drawing No. 3. 340
Figure 12.58 Example of discharge trajectory: Drawing No. 4. 341
Figure 12.59 Example of discharge trajectory: Drawing No. 5. 341
Figure 12.60 Example of discharge trajectory: Drawing No. 6. 342
Figure 12.61 Example of discharge trajectory: Drawing No. 7. 342
CHAPTER 13 Conveyor Motor Drives and Controls
Figure 13.1 Typical AC motor torque versus speed curve. 347
Figure 13.2 AC induction motor motoring and regeneration. 351
Figure 13.3 AC motor with full voltage starting and direct coupling. 353
Figure 13.4 SC motor with reduced voltage starting and direct coupling. 355
Figure 13.5 Wound rotor induction motor with a stepper secondary control and
direct couplings. 357
Figure 13.6 Binary stack secondary for WRIM control. 358
Figure 13.7 DC shunt motor speed vs. voltage. 361
Figure 13.8 DC shunt motor torque vs. speed. 361
Figure 13.9 DC shunt motor with SCR armature control and direct coupling. 362
Figure 13.10 Variable frequency AC motor and direct coupling. 364
Figure 13.11 AC motor with fixed fill fluid coupling. 366
Figure 13.12 AC motor with variable fill hydrokinetic coupling. 368
Figure 13.13 AC motor and variable mechanical transmission coupling. 370
CHAPTER 14 Operation, Maintenance, and Safety
No figures.
APPENDIX A Guide for Use of SI (Metric) Units
Figure A.1 Illustration of difference between mass (unit: kilogram) and force
(Huntington). 391
APPENDIX B Nomenclature
No figures.
APPENDIX C Belt Tension to Rotate Pulleys
No figures.List of Figures
xxiv
APPENDIX D Conveyor Installation Standards For Belt Conveyors
Handling Bulk Materials
Figure D.1 Maximum tolerances for channel frame of angle stringers. 409
Figure D.2 Maximum allowable lateral offset in conveyor stringers. 409
Figure D.3 Conveyor frame and idler alignment. 410
Figure D.4 Level requirements. 410
Figure D.5 Shaft elevation settings. 411
Figure D.6 Shaft elevation settings. 411
Figure D.7 Angular alignment. 413
Figure D.8 Parallel alignment. 414
Figure D.9 Axial alignment. 414
Figure D.10 Correcting belt alignment. 416xxv
CHAPTER 1 Belt Conveyor General Applications and Economics
Table 1-1. Owning and operating costs — conveyor haul. Annual expenditures in
current dollars. 15
Table 1-2. Owning and operating costs — truck haul. Annual expenditures in
current dollars. 16
Table 1-3. Cash flow — conveyor system. In 000’s of dollars. 17
Table 1-4. Cash flow — truck system. In 000’s of dollars. 17
Table 1-5. Present value annual costs discounted at 20%. In 000’s of dollars. 18
CHAPTER 2 Design Considerations
No tables.
CHAPTER 3 Characteristics and Conveyability of Bulk Materials
Table 3-1. Flowability-angle of surcharge-angle of repose. 30
Table 3-2. Material class description. 32
Table 3-3. Material characteristics and weight per cubic foot. 33
CHAPTER 4 Capacities, Belt Widths, and Speeds
Table 4-1. Recommended maximum belt speeds. 48
Table 4-2. 20-degree troughed belt—three equal rolls standard edge distance =
0.055b + 0.9 inch. 53
Table 4-3. 35-degree troughed belt—three equal rolls standard edge distance =
0.055b + 0.9 inch. 53
Table 4-4. 45-degree troughed belt—three equal rolls standard edge distance =
0.055b + 0.9 inch. 54
Table 4-5. Flat belt capacity standard edge distance = 0.055b + 0.9 inch. 54
List of TablesList of Tables
xxvi
CHAPTER 5 Belt Conveyor Idlers
Table 5-1. Idler classification. 56
Table 5-2. Suggested normal spacing of belt idlers (Si). 64
Table 5-3. A — Half trough recommended minimum transition distances. 66
Table 5-3. B — Full trough recommended minimum transition distances. 66
Table 5-4. Belt speeds at 500 rpm. 69
Table 5-5. WB-Estimated average belt weight, multiple- and reduced-ply belts, lbs/
ft. 72
Table 5-6. K1-Lump adjustment factor. 72
Table 5-7. Load ratings for CEMA B idlers, lbs (rigid frame). 76
Table 5-8. Load ratings for CEMA C idlers, lbs (rigid frame). 76
Table 5-9. Load ratings for CEMA D idlers, lbs (rigid frame). 77
Table 5-10. Load ratings for CEMA E idlers, lbs (rigid frame and catenary where
applicable). 77
Table 5-11. Average weight (lbs) of troughing idler rotating parts-steel rolls. 83
Table 5-12. Average weight (lbs) of return idler rotating parts-steel rolls. 83
Table 5-13. WK2(lb-in2) average for three equal-roll troughing idlers. 84
Table 5-14. WK2(lb-in2) average for single steel return idlers. 84
CHAPTER 6 Belt Tension, Power, and Drive Engineering
Table 6-1. Estimated average belt weight, multiple- and reduced-ply belts, lbs/ft. 90
Table 6-2. Factor K
y values. 92
Table 6-3. Corrected factor K
y values when other than tabular carrying idler
spacings are used. 95
Table 6-4. A and B values for equation Ky = (Wm + Wb) x A x 10-4 + B x 10-2. 96
Table 6-5. Belt tension to rotate pulleys. 98
Table 6-6. Discharge plow allowance. 100
Table 6-7. Skirtboard friction factor, Cs. 102
Table 6-8. Wrap factor, Cw (Rubber-surfaced belt). 105
Table 6-9. Wrap limits. 106
Table 6-10. Recommended belt sag percentages for various full load conditions. 116
Table 6-11. Final tensions, full and reduced friction. 152
Table 6-12. Mechanical efficiencies of speed reduction mechanisms. 181
Table 6-13. Backstop and brake recommendations. 186
CHAPTER 7 Belt Selection
Table 7-1. Properties of covers. 200
Table 7-2. General purpose rubber cover and ply adhesion. 201
Table 7-3. Conveyor belt cover quality selection. 202
Table 7-4. Suggested minimum carry thickness for normal conditions: RMA—
Grade II belting. 203
Table 7-5. Suggested minimum pulley cover thickness: RMA—Grade II belting.
203xxvii
List of Tables
Table 7-6. Deteriorating conditions for conveyor belt covers. 204
Table 7-7. Guide for minimum protective rubber “F”. 207
Table 7-8. Some materials used in belting reinforcement (belt carcass). 208
Table 7-9. Recommended take-up travel in percent of center distance. 215
Table 7-10. Estimated maximum impact rating multi- or reduced-ply belts in footpounds (Joules). 217
Table 7-11. Lump weight factor in pounds. 218
Table 7-12. Recommended pulley face width and belt clearances. 219
Table 7-13. Typical ratings for multi- or reduced-ply conveyor elevator rubber
belting. 221
Table 7-14. Typical ratings for straight warp conveyor or elevator rubber belting.
222
Table 7-15A. Typical ratings for pvc solid woven conveyor and elevator belting
(Table A). 223
Table 7-15B. Typical ratings for pvc solid woven conveyor and elevator belting
(Table B). 224
CHAPTER 8 Pulleys and Shafts
Table 8-1. Welded steel drum pulley weights, pounds. 230
Table 8-2. Welded steel wing pulley weights, pounds. 232
Table 8-3. Permissible face widths tolerances. 234
Table 8-4. Permissible runout tolerances for common applications. 234
Table 8-5. Permissible runout tolerances for high modulus belts. 234
CHAPTER 9 Vertical Curves
Table 9-1. Belt modulus values. 245
Table 9-2. Belt conveyor carrying idler trough angles. 245
Table 9-3. Location of tangent points on concave vertical curves. 253
Table 9-4. Ordinate distances of points on concave vertical curves. 253
Table 9-5. Trough angle of the carrying idlers. 254
Table 9-6. Minimum bend pulley diameter. 258
CHAPTER 10 A Guide to Steep Angle Conveying
Table 10-1. Guide to maximum allowable angles of incline with deep molded cleat
belts. 263
Table 10-2. Steep angle conveying capacity reduction, Method 2. 267
CHAPTER 11 Belt Takeups, Cleaners, and Accessories
Table 11-1. Recommended takeup movements. 283List of Tables
xxviii
CHAPTER 12 Conveyor Loading and Discharge
Table 12-1A Minimum uncovered skirtboard height for 20° three-equal-roll
troughing idlers. 312
Table 12-1B Minimum uncovered skirtboard height for 35° and 45° three-equal-roll
troughing idlers. 312
Table 12-2A Load height and center of gravity at discharge pulley, idlers at 20° and
35°. 329
Table 12-2B Load height and center of gravity at discharge pulley, idler at 45° and flat
belt idler. 330
Table 12-3. Fall distance for time intervals. 335
CHAPTER 13 Conveyor Motor Drives and Controls
No tables.
CHAPTER 14 Operation, Maintenance, and Safety
Table 14-1. Belt conveyor troubleshooting — causes and cures. 382
Table 14-2. Belt conveyor troubleshooting — complaints and recommended
resolutions. 382
APPENDIX A Guide for Use of SI (Metric) Units
Table A-1. Commonly used conversion factors. 389
APPENDIX B Nomenclature
Table B-1. Nomenclature. 400
APPENDIX C Belt Tension to Rotate Pulleys
Table C-1. T
p determination — graphical method for fabric carcass belts. 406
Table C-2. T
p determination — graphical method for steel cable belts. 406
APPENDIX D Conveyor Installation Standards For Belt Conveyors
Handling Bulk Materials
No tables.
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