Table Of Content

THEORY AND OPERATION OF THE FOURDRINIER PAPER MACHINE THEORY AND OPERATION OF THE FOURDRINIER PAPER MACHINE BY G. H. NUTTALL, M.A. (Cantab.) LONDON: S. C. PHILLIPS & CO. LTD. © G. H. Nuttall PRINTED IN GREAT BRITAIN BY ADLARD & SON LTD., BARTHOLOMEW PRESS, DORKING CONTENTS Foreword ix PART 1: THE WET-END FLOW SYSTEM 11 Introduction 3 CHAPTER lA: THEORETICAL CONSIDERATIONS. lA. 1 Flow of Fibre Suspensions . 6 lA.2 Influence of Wet-end Design on Operational Stability 15 CHAPTER lB: OPERATING FACTORS AFFECTING PERFORMANCE. lB. 1 Retention on the Wire 31 lB.2 Fresh Stuff Flow and Mixing 35 lB. 3 Backwater and Whitewater Systems 38 lB.4 Breast Box Approach System 40 lB. 5 Breast Box Design 46 1B. 6 Slice Design 54 1B. 7 Aeration of the Stock 59 lB. 8 Hydraulic Disturbances 63 CHAPTER lC: RUNNING THE WET-END FLOW SYSTEM. 1 C. 1 Daily Operation 66 lC.2 Maintenance 76 1C.3 Control of Substance . 80 1 C .4 Practical Points . 87 References 95 PART 2: SCREENS AND CLEANERS 21 Introduction 101 CHAPTER 2A: THEORETICAL CONSIDERATIONS. 2A. l Theory of Screening . 105 2A. 2 Theory of Cleaning . 117 2A. 3 Assessing Screen and Cleaner Efficiency 129 CHAPTER 2B: OPERATING FACTORS AFFECTING SCREENS AND CLEANERS. 2B. I Position in the Flow System 135 28. 2 Open Screening Equipment 140 2B . 3 Closed Pressure Screens 144 28. 4 Early Cleaning Equipment . 150 2B.5 Cylindrical Cleaners . 152 2B. 6 Cyclone Cleaners 154 CHAPTER 2C: RUNNING SCREENS AND CLEANERS. 2C. I Daily Operation 17 1 2C. 2 Maintenance 172 2C. 3 Practical Points 17 5 References 180 v CONTENTS PART 3: THE WIRE SECTION 31 Introduction 185 CHAPTER 3A: THEORETICAL CONSIDERATIONS. 3A. l Drainage in the Table Roll Section 187 3A. 2 Forming the Sheet on the Wire 195 3A. 3 Drainage at the Suction Boxes 209 3A .4 Conditions for Couching . 219 CHAPTER 3B: OPERATING FACTORS AFFECTING THE WIRE SECTION. 3B.1 Early Drainage Conditions. 226 3B. 2 Table Rolls and other Dewatering Devices 232 3B. 3 Shake 237 3B . 4 Suction Boxes 241 3B. 5 The Dandy 247 3B. 6 Couching . 252 3B. 7 The Wire and Showers 262 3B. 8 Breast Box Stock Consistency and Temperature 268 38. 9 Machine Speed, Substance and Stuff Treatment 269 3B.10 Equipment 271 CHAPTER 3C: RUNNING THE WIRE SECTION. 3C. 1 Daily Operation 275 3C. 2 Maintenance 280 3C. 3 Practical Points 286 References 296 PART 4: THE PRESS SECTION 41 Introduction 303 CHAPTER 4A: GENERAL THEORY OF PRESSING. 4A. 1 Early Theory 306 4A.2 Modern Theory of Pressing 310 CHAPTER 4B: OPERA TING FACTORS AFFECTING PRESS PERFORMANCE. 4B. l Press Load and Nip Width 318 48.2 Felts and Felt Cleaning 320 4B. 3 Felt and Paper Runs . 325 4B .4 Suction Roll Conditions 332 4B. 5 Machine Speed and Draw Control 335 4B. 6 Moisture Content of Paper entering Press 337 4B. 7 Paper Properties 339 4B. 8 Temperature 340 4B. 9 Equipment 342 CHAPTER 4C: RUNNING THE PRESS SECTION. 4C. I Daily Operation 345 4C. 2 Maintenance 350 4C. 3 Cross-web Variations 355 4C. 4 Practical Points 360 References 366 vi CONTENTS PART 5: THE DRYING SECTION AND CALENDERS SI Introduction 371 CHAPTER SA: THEORETICAL CONSIDERATIONS SA.1 Removal of Water in Drying 373 SA. 2 Performance of the Drying Section 387 SA. 3 Effect of Drying on Paper Properties 394 SA.4 Calendering 411 CHAPTER SB: OPERATING FACTORS AFFECTING DRYING AND CALENDERING. SB. 1 Steam Heating and Condensate System 422 SB. 2 Felts and Felt Drying 434 SB. 3 Conditions inside the Dryers 444 SB.4 Ventilation 453 SB. 5 Auxiliary Drying Methods . 461 5B.6 Machine Speed and Draw Control 471 SB. 7 Paper Properties 475 SB.8 The M.G. Cylinder 476 SB. 9 Calenders 481 SB. 10 Equipment 487 CHAPTER SC: RUNNING THE DRYERS AND CALENDERS. SC. 1 Daily Operation 497 SC. 2 Maintenance 506 SC. 3 Control of Moisture Content 515 SC .4 Control of Thickness . 528 SC. 5 Practical Points 535 References 546 PART 6: PRODUCTION CONTROL 61 Introduction 553 CHAPTER 6A: MONITORING MACHINE PERFORMANCE. 6A. 1 Analysis of Downtime 556 6A.2 Performance Data 561 6A. 3 Monitoring Quality . 570 CHAPTER 6B: IMPROVING MACHINE PERFORMANCE. 6B. l General Survey . 581 6B. 2 Financial Considerations 586 6B. 3 Performance under Different Operating Conditions 600 References 613 Index 615 Vll