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| موضوع: كتاب Belt Conveyors for Bulk Materials السبت 17 نوفمبر 2018, 1:56 pm | |
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أخوانى فى الله أحضرت لكم كتاب 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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