Background Report Reference
AP-42 Section Number: 9.7
Background Chapter: 2
Reference Number: 2
Title: Control Technology Assessment of Raw Cotton Processing Operations
Enviro Control Inc.
June 1980
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AP-42 Section a Reference = ~eport sec t . L Reference -%--
Control Technology Assessment Of Raw Cotton Processing Operations
Contract No. 210.780001
JunelS, 1980
SUBMnrr[)rn Mr. Robert T. Hughes National Inswute for Occupational !MetYamlHeahh clndnnati. Ohio
SUBMlTTED BY Emriro contml. lac One Centxal Plaza 11300 RochvIlle pike Rodrvine 20852
N A T I O N A L TECHNICAL I N F O R M A T I O N SERVICE
U S D l v I n I y 1 1 1 01 ~ 0 1 1 1 1 ~ 1 I p I I I C I I I L 3 11 !:I61
AESTRACT
Cotton d u s t has required implementation of control tech- nology to reach permissible exposure leve ls o f 200 pg/m3 i n yarn manufacturing, 500 vg/m3 i n cottonseed processing, k n i t - t i n g and waste processing and 750 vg/m3 i n slashing and weav- ing . A control technoloqy assessment was made by conducting preliminary and detailed surveys i n cotton ginning, cotton- seed processing, yarn manufacturing, k n i t t i n g , weaving, and waste processing operations tha t u t i l i z e raw cotton. Plants were selected t h a t were u t i l i z ing control technology, as fol lows :
0 Local and general exhaust vent i la t ion 0 Air f i l t r a t i o n equipment 0 Work practfces 0 Process enclosure and isolat ion 0 Personal protective equipment 0 L i q u i d oversprays
Ti ? resu l t s of the study a re usable a s a reference by both government and industry personnel concerned w i t h cotton dust control. A number o f areas i n which applications of en- gineering control equipment f o r dust emission control can be improved o r are l ike ly candidates for research were also identified .
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COtiTENTS
DISCLAIMER .......................................................... ii
ABSTRACT .......................................................... i f f
ACKNOWLEDGMENTS .................................................. x i v
INTRODUCTION ........................................................ 1
INDUSTRY OVERVIEW ................................................... 7
SUMMARY AND CONCLUSIONS ............................................ 11
RECOMMENDATIONS .................................................... 19
INDEX OF CONTROL TECHNIQUES FOR COTTON WST ........................ 24
APPENDICES
37
37
A. l . Cot ton Ginning ............................................ A.1.0 Overview - Process Flow and Exposure Patterns ...... A . l . l Seed Cotton Feeding 43' ................................
43 A . l . l . l Module Feeding ............................ A.1.1.2 Suct ion Shed Feeding -
45 Personal P ro tec t i ve Devices ............... 46 A.1.2 Ginning ............................................
A.1.2.1 Exhaust V e n t i l a t i o n a t Feeders ............ 46 49 A.1.2.2
A.1.3 Ba l ing 51
App l i ca t i on o f L i q u i d Overspray (X-78) .... .............................................
A.1.3.1 App l i ca t i on o f Humid A i r a t L i n t S l i d e .... 51 A.1.3.2 Local Exhaust V e n t i l a t i o n a t L i n t S l i d e ... 55
Press 59 A.1.3.3 Process I s o l a t i o n f o r F ixed Box Bale
.................................... A.1.4 Seed Scale 62
A.1.4.1 Local Exhaust V e n t i l a t i o n a t Seed Scale ... 62
A.1.5 Gin P l a n t Design ................................... 68 70 A.1.5.1 Make-up A i r Intakes .......................
A.1.5.2 Cyclone P o s i t i o n i n g ....................... 71 A.1.5.3 Locat ion o f M a t e r i a l Handling Fan ......... 71 A.1.5.4 P a r t i t i o n i n g .............................. 72 A.1.5.5 Exposure I s o l a t i o n ........................ 72 A . l . 5.6 Automatic Overflow Recyl i n g ............... 72 A.1.5.7 L i n t Cleaner Process A i r .................. 73 A.1.5.8 Automatic Banding and Bale Removal ........ 74
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A.2. Cottonseed Processing ..................................... 75 A.2.0 Overview - Process Flow ar!d Exposure Patterns ...... 75
A.2.1 Cottonseed Unloading Operations .................... 83 A.2.1.1 Personal Pro tec t ion Devices ............... 83
A.2.2 Cottonseed Feeding ................................. 83
A.2.3 Cottonseed Cleaning Operation ...................... 85 A.2.3.1 Conveyor Enclosure ........................ 86 A.2.3.2 Local Exhaust V e n t i l a t i o n f o r Overhead
Conveyor ................................. E6 A.2.3.3 Local Exhaust V e n t i l a t i o n a t Overflow
S t a t i o n .................................. 88 A.2.3.4 Enclosure Design and Local Exhaust
V e n t i l a t i o n .............................. 90 A.2.3.5 Sand and B o l l Reel ........................ 92 A.2.3.6 Process A i r Design a t Shaker Cleaners ..... 92 A.2.3.7 h t o m a t i c Recycling o f Cottonseed
Overf low ................................. 92
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A.2.4 Cottonseed Oe l i n te r i ng Operation ................... 98 A.2.4.1 Local Exhaust V e n t i l a t i o n a t Seed
Conveyor ................................. 98 A.2.4.2 Enclosed L i n t e r Machine ................... 100 A.2.4;3 Rock and Sh?le Separator ................. 103 A.2.4.4 L i n t e r Transport System .................. 106 A.2.4.5 L i n t e r Machine Hatch Covers .............. 106
A.2.5 Cottonseed H u l l i n g and Separating Operation ....... l i 2 A.2.5.1 H u l l e r Machine Enclosure ................. 112 A.2.5.2 Recycle Seed Vacuum Box .................. 112 A.2.5.3 Local Exhaust V e n t i l a t i o n a t H u l l e r
Machines ................................ 117 A.2.5.4 Local Exhaust V e n t i l a t i o n a t Conveyor .... 117 A.2.5.5 Local Exhaust V e n t i l a t i o n a t
Decor t i ca to r ............................ 121
A.2.6 Cottonseed L i n t e r Beating ......................... 127 A.2.6.1 Cyclone Separator a t L i n t e r Beaters ...... 127
A.2.7 Bale Press ........................................ 129 A.2.7.1 Local Exhaust V e n t i l a t i o n f o r Fixed
Box Bale Press .......................... 129 A.2.7.2 Local Exhaust V e n t i l a t i o n a t V e r t i c a l
Bale Press .............................. 132 A.2.7.3 P u l l Through L i n t e r Transport System ..... 136 A.2.7.4 Process I s o l a t i o n f o r Fixed Box Bale
Press ................................... 136
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A.3. Yarn Manufacturing and Preparat ion ........................ 141
A.3.0 Overview - Process Flow and Exposure Pat terns ...... 141
A.3.1 Cotton Opening and Feeding ......................... 148 148 A.3.1.1 Automatic Feeding .........................
A.3.1.2 Local Exhaust V e n t i l a t i o n o f Opening Hoppers 148
A.3.1.3 Local Exhaust V e n t i l a t i o n o f Waste Gr inder 148
A.3.1.4 Pneumatic Transport from Opening Hoppers 148
A.3.1.5 A.3.1i.6 Time Cycle Waste Ex t rac to r ................ 156 A.3.1.7 Enclosure and Exhaust V e n t i l a t i o n of
Opening Hoppers and Conveyor L i n e ........ 162 A.3.1.8 Local Exhaust V e n t i l a t i o n o f Waste
A.3.1.9 Local Exhaust V e n t i l a t i o n o f Opening
A.3.1.10 Local Exhaust V e n t i l a t i o n o f Opening
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.................................. Automatic Feeding (Bale-0-Mat) ............ 156
Gr inder .................................. 162
Hoppers and Conveyor Feed ................ 168
Hopper and Pneumatic Transport System .... 174
A.3.2 Cleaning ........................................... 179
A i r Flow i n Cleaning ..................... 179 Process Equipment f o r Cleaning Cotton ..... 179
A.3.3 Carding ........................................... 184
A.3.3.2 Carding Local Exhaust V e n t i l a t i o n ........ 184
A.3.2.1 Local Exhaust V e n t i l a t i o n and Process
A.3.2.2
A.3.3.1 Chute Feed System ......................... 184
A.3.3.3 Local Exhaust V e h t i l a t i o n and Modern High Product ion Carding .................. 192
A.3.3.4 Local Exhaust V e n t i l a t i o n f o r High Speed Carding Machines ................... 198
198 A.3.3.5 A u t o m t i c Waste Co l l ec t i on System ......... A.3.4 Drawing 203
A.3.4.1 Exhaust V e n t i l a t i o n a t Drawing Frames ..... 203 A.3.4.2 F ine Mesh Co l l ec to r Screens f o r Drawing
Frames ................................... 206
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A.3.5 Spinning 21 0 Open-End Spinninq Technology .............. 210 Open-End Spinning Exhaust V e n t i l a t i o n ..... 210
........................................... A.3.5.1 A.3.5.2 A.3.5.3 Exhaust V e n t i l a t i o n f o r Broken End
C o l l e c t o r Un i t s a t Spinning Frames ....... 216
A.3.6 Winding ............................................ 219 A.3.6.1 Manual Winder Exhaust V e n t i l a t i o n ......... 219
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A.3.7 Waste Processing .................................. 223 A.3.7.1 Vacuum Waste Collection System ........... 223 A.3.7.2 Automatic Waste Baling ................... 223
A.3.8 Liquid Overspray . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226 A.3.8.1 0.20% Add-on a t Opening - S i t e t l ........ 226 A.3.8.2 0.47% Add-on a f t e r Cleaning . . . . . . . . . . . . . . 228
A.3.9 Air F i l t ra t ion Systems ............................ 230 A.3.9.1 Open-End Yarn Manufacturing . . . . . . . . . . . . . . 230 A.3.9.2 High Production Carding .................. 236 A.3.9.3 Opening. Cleaning and Carding Exhaust
Air . . . . . . . . . . . . . . . i . . . . . . . . . . . . . . . . . . . . . 242 A.3.9.4 Opening and Cleaning ..................... 249
A.3.10 General Ventilation Systems. .. . . . . . . . . . . . . . . . . . . . . . 254 A.3.10.1 Percale Sheeting Plant .. . . . . . . . . . . . . . . . . . 255 A.3.10.2 Open-End Yarn Mawfacturing Plant . . . . . . . . 259
A.4. Fabric Manufacturing .............................. 260
A.4.0 Overview - Process Flow and Exposure Patterns ..... 260
A.4.1 Weaving General Ventilation .. . ... .. . . . . . ..... .. . . . 261
Waste Processing ......................................... 263
A.5.0 Overview - Process Flow and Exposure Patterns .... 263
A.5.1 Waste Processing Control Techniques . . . . . . . . . . . . . . . 265 A.5.1.1 Local Exhaust Ventilation a t Feed Apron . . 266 A.5.1.2 Isolation o f Feeding Operation ........... 268
Waste Opening and Cleaning Operations .............. 270 A.5.2.1 Exhaust Ventilation of Opening Hoppers ... 270 A.5.2.2 Enclosure and Ventilation of Conveyor
Line ..................................... 270 A.5.2.3 Pneumatic Trash Removal a t Cleaning Line.. 270 A.5.2.4 Local Exhaust Ventilation a t Opening
Hoppers ................................. 277 A.5.2.5 Automatic Trash Removal a t Opening and
Cleaning ................................ 277 A.5.2.6 Liquid Overspray . . . . . . . . . . . . . . . . . . . . . . . . . 277
Bale Press Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 281 A.5.3.1 Local Exhaust Ventilation a t Bale Press. .. 281
A.5.4 Air F i l t ra t ion and Trash Collection ............... 284 A.5.4.1 Air F i l t r a t ion With Tandem Rotary Orun
System . . .. ... . . . . ... .. . .. .... . . ... . ..... 284 A.5.4.2 Air F i l t r a t ion W i t h Stationary F i l t e r
System and Automatic Trash Collection ... 287
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A.5.2
A.5.3
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A.6. Personal P ro tec t i ve Equipment ............................ 290
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Ginning .................................................. 291 Cottonseed Processing 291 T e x t i l e Manufacturing 292
Work Prac t ices 294
A.7.0 Work Prac t ices .... ;. .............................. 294
294 A.7.1 Cont ro l led Use o f Compressed A i r .................. Sweeping 294
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A.7.1.1 E l im ina t i ng Compressed A i r f o r F loor
A.7.1.2 C o n t r o l l i n g Compressed A i r f o r Machine
A.7.1.3 R e s t r i c t i n g Compressed A i r Cleaning t o
................................ Cleaning ................................ 294
Proper ly Designed Containers ...................... 294 A.7.2.1 Covered Waste Containers ................. 295 A.7.2.2 Keeping Loose Cotton o f f the Floor ....... 295
A.7.3 Manual Handling o f Cotton ......................... 296 A.7.3.1 Feeding Cotton t o Process Equipnent ...... 296 A.7.3.2 Brushing or Wiping Machine Surfaces ...... 296 A.7.3.3 Floor Sweeping ........................... 296
Cotton Dust Sampling Equipment ............................. 297
B.l GCA Respirable Dust Moni tor 101-4 .................... 298 8.2 TSI-3500 Respirable Aerosol Monitor ................... 301 8.3 Continuous Aerosol Moni tor ............................ 305 B.4 Sierra-132 Cotton Oust Sampler ........................ 310 B.5 General Metal Works-4000 Cotton Gust Sampler .......... 315
Analyses Procedures
C . l Summary o f Sampling Equipment and Procedures .......... 334 C.2 O i l M i s t / V a p o r Analys is ............................... 336 C.3 Cotton Oust Chemical Composition Analysis ............. 339
Chemical Composition o f Cotton Oust Samples ................ 341
costs ...................................................... 344
Glossary ................................................... 348
Times Product ion i s Stopped ............. 295
A.7.2
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.. I t i l
F igu re 1 F igu re A.l-1
F igure A.l-2 F igu re A.l-3 F igure A.l-4 F igu re A.l-5 F igu re A.l-6 F igu re A.l-7 F igu re A.l-8
F igu re A.l-9
F igu re A.l-10 F igu re A.2-1
F igu re A.2-2 F igu re A.2-3 F igu re A.2-4 F igu re A.2-5 F igu re A.2-6
F igure A.2-8 F igu re A.2-9 F igure A.2-10 F igure A.2-11 F ioure A.2-12 F igure A.2-13 F igu re A.2-14 F igu re A.2-15 F igu re A.2-16 F igu re A.2-17
F igure A.2-18 F igure A.2-19 F igu re A.2-20 F igu re A.2-21
F igu re A.2-22
F igu re A.2-23 F igu re A.2-24
F igu re A.2-7
FIGURES
.Page Flow Diagram - Raw Cotton Processing 8 Index of Contro l Techniques and Processing ..................................... 38 Var iab les Process Flow Diagrams - Cotton Gins ............ 40 Module Feeding System 44 Feeder Exhaust V e n t i l a t i o n System .............. 48 L i n t S l i d e w i t h Humid A i r ...................... 53 Exhaust V e n t i l a t i o n a t L int S l i d e .............. 57
61 Uni-Den F ixed Box Bale Press ................... Local Exhaust V e n t i l a t i o n a t Seed Scale -
S i t e #1 64 Local Exhaust V e n t i l a t i o n a t Seed Scale - P l o t Plan of New Gin ........................... 69 Index of Contro l Techniques and Processing Var iab les ..................................... 76
Cot tmseed Process Flow D e s c r i p t i o n ............ 79 Seed Dumn ...................................... 84
84 07 89
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....................................... S i t e #2 ....................................... 67 .
. _ _ ~ ~- Seed Storage ................................... Exhaust V e n t i l a t i o n a t Conveyor ................ Exhaust V e n t i l a t l o n a t Cottonseed Overf low ..... Enclosure Design and Exhaust V e n t i l a t i o n a t
Shaker Cleaners ............................... P l o t Plan f o r Seed Cleaning Department ......... Sand and B o l l Reel ............................. Process A i r Design a t Shaker Cleaners .......... Comparison o f L i n t e r Machine Enclosures ........ Rock And Shale Separator .......................
91 93 95 97 02 05
L i n t e r Transpor t System ........................ 07 Enclosure Design o f D e l i n t e r i n g Machine ........ 111 H u l l e r Machine Enclosure ....................... 114 Recycle Seed Vacuun; BOX ....................... 115 Local Exhaust V e n t i l a t i o n a t H u l l e r Machine ....................................... 119
Local Exhaust V e n t i l a t i o n a t Conveyor .......... 124 Local Exhaust V e n t i l a t i o n a t D e c o r t i c a t o r D e c o r t i c a t o r ................................... 125 Local Exhaust Y e n t l l a t i o n f o r F ixed Box
Bale Press .................................... 131 Local Exhaust V e n t i l a t i o n f o r Ver t i ca l
Bale press .................................... 134
Process I s o l a t i o n f o r F ixed Box Ba le P u l l Through L i n t e r Transpor t System ........... 138
Press ......................................... 140
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Figure A.3-1 Index o f Control Techniques and Processing Var iables .....................................
Figure A.3-2 Hopper Feed Table - Bale-0-Matic ............... Figure A.3-3 Local Exhaust V e n t i l a t i o n f o r Waste Grinder . .. . Figure A.3-4 Enclosure f o r Opening Hopper ................... Figure A.3-5 Tiwe Cycle Waste Co l l ec to r ..................... Figure A.3-6 Enclosure and Exhaust .Vent i la t ion of Opening
Hoppers and Conveyor L ine ..................... Figure A.3-7 Opening Department Local Exhaust V e n t i l a t i o n . . . Figure A.3-8 Forked Brace i n Opening Hoppers ................ Figure A.3-9 Local Exhaust V e n t i l a t i o n and Enclosure
Design o f Opening Hoppers ..................... Figure A.3-10 Rando Cleaner and Local Exhaust V e n t i l a t i o n . .. . Figure A.3-11 Enclosure Design and Local Exhaust V e n t i l a t i o n
a t Chute Feed ............................. ;.... Figure A.3-12 Carding Local Exhaust V e n t i l a t i o n . . . . . . . . . . . . . . Figure A.3-13 Card Cleaning System ........................... Figure A.3-14 Card Cleaning System ...........................
- F igure A.3-15 Exhaust V e n t i l a t i o n a t Drawing Frames .......... Figure A.3-16 Open-End Spinning Technology . . . . . . . . .. . . . . . . . . . Figure A.3-17 Open-End Spinning Exhaust V e n t i l a t i o n . . . . . . . . . . Figur? A.3-18 Exhaust V e n t i l a t i o n for Winders ................ Figure A.3-19 A i r F i l t r a t i o n Schematic f o r Sect ion A.3.9.1 ... Figure A.3-20 Return and Supply A i r A f t e r 2nd F i l t e r
Stage f o r Sect ion A.3.9.1 ..................... Figure A.3-21 A i r F i l t r a t i o n Schematic f o r Sect ion A.3.9.2 ... Figure A.3-22 Return and Supply A i r A f t e r RD 81 and RD 612
f o r Sect ion A.3.9.2 ........................... Figure A.3-23 A i r F i l t r a t i o n Schematic f o r Sect ion A.3.9.3 ... Figure A.3-24 Return and Supply A i r A f t e r RD 81 for
Sect ion A.3.9.3 ............................... Figure A.3-25 Return and Supply A i r A f t e r RD #2 f o r
Sect ion A.3.9.3 ............................... Figure A.3-26 A i r F i l t r a t i o n Schematic f o r Sect ion A.3.9.4 ... Figure A.3-27 Return and Supply A i r t o RDF f o r
Sect ion A.3.9.4 ............................... Figure A.3-28 A i r F i l t r a t i o n Schematic f o r Sect ion A.3.10.1 .. Figure A.5-1 Exhaust V e n t i l a t i o n a t Opening L ine F igure A.5-2 P l o t Plan - Waste Processing Operations ........ Figure A.5-3 Local Exhaust V e n t i l a t i o n o f Opening Hoppers ... Figure A.5-4 Local Exhaust V e n t i l a t i o n and Enclosure Design
a t Conveyor L ine .............................. Figure A.5-5 Local Exhaust V e n t i l a t i o n a t Opening Hoppers ... Figure A.5-6 Waste Process Flow Diagram ..................... Figure A.5-7 Automatic Trash C o l l e c t i o n .....................
142 151 153 155 161
164 ~. ~
170 173
176- 181
187 188 194 200 205 21 2 214 221 231
235 237
240 243
247
248 250
253 258 267 269 272
275 279 285 28 9
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F igu re 8.2-1 P a r t i c l e S ize D i s t r i b u t i o n - Figure e.4-1 P a r t i c l e S ize D i s t r i b u t i o n - F igu re P.4-2 P a r t i c l e S ize D i s t r i b u t i o n - F igu re 8.5-1 P a r t i c l e S ize D i s t r u b u t i d - GMW YE
F igure 8.5-2 P a r t i c l e S ize D i s t r i b u t i o n - GMN VE '
F igure 8.5-3 P a r t i c l e S ize D i s t r i b u t i o n - GMW VE
F igu re 8.5-4 P a r t i c l e S ize D i s t r i b u t i o n - GMW VE
F igu re 8.5-5 P a r t i c l e S i i e D i s t r i b u t i o n - GMW VE
F igu re 8.5-6 P a r t i c l e S i ze D i s t r i b u t i o n - GMH VE
F igure 8.5-7 P a r t i c l e S i ze D i s t r i b u t i o n - GMW VE
F igu re 8.5-8 P a r t i c l e S ize D i s t r i b u t i o n - GMW VE
F igu re 8.5-9 P a r t i c l e S i ze D i s t r i b u t i o n - GMW VE
F igu re 8.5-10 P a r t i c l e S i ze D i s t r i b u t i o n - GMW YE
F igu re 8.5-11 P a r t i c l e S i ze D i s t r i b u t i o n - GMW VE
F igu re 8.5-12 P a r t i c l e S ize D i s t r i b u t i o n - GMW YE
F igu re 8.5-13 P a r t i c l e S ize D i s t r i b u t i o n - GMW VE
F igu re 8.5-14 P a r t i c l e S ize D i s t r i b u t i o n - GMW VE
F igu re B.5-15 P a r t i c l e S ize D i s t r i b u t i o n - GW YE
T S I V e r t i c a l E l u t r i a t o r ....................... S i e r r a V e r t i c a l E l u t r i a t o r .................... S i e r r a V e r t i c a l E l u t r i a t o r .................... Yzrn Hanufacturing-Opening Process ............ Yarn Manufactur ing Opening Process ............ Yarn Manufactur ing Cleaning Process ............ Yam Manufactur ing Carding Process ............ Yam Manufactur ing Carding Process ............ Yarn Manufactur ing Drawing Process ............ Yarn Manufactur ing Spinning Process ........... Yam Manufactur ing Spinning Process ........... Yarn Manufac tur ing Spoo l ing Process ........... Yarn Manufactur ing Winding Process ........... Fabr i c Manufactur ing Weaving Process .......... Non-Text i le Waste Processing .................. Non-Text i le Ginning ........................... Non-Text i le Cottonseed Processing ............. Fon-Tex t i l e Cottonseed Processing .............
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304
31 3
3 i 5
31 9
320
321
322
323
324
325
326
327
328
329
330
331
332
333
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Table 1. Table 2.
Table 3. Table 4 ~~ ~ .
Table 5. Table A.2-1. Table A.2-2.
Table A.3-1, Table A.3-2. Table A.3-3. Table A.3-4. Table A.3-5. Table A.3-6.
Table A.3-7.
TABLES
Sumnary of Dust Measurements - Cotton Ginning ..... 12 Summary o f Dust Measurements - Cottonseed
Processing .. . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Summary o f Oust Measurements - Yarn Yanufacturing.. 15 Summary o f Oust Measurements - Fabr ic Manufacture.. 16 Summary o f Dust Measurements - Waste Processing ... 17 Local Exhaust V e n t i l a t i o n f o r Shaker Cleaners. ..... 90 Sumnary o f D e l i n t e r i n g Processing Deta i led
Surveys .......................................... 108 Local Exhaust V e n t i l a t i o n a t Opening Hoppers ..... 152 Process Transport A i r - Opening Lines ............ 154 A i r Flow Data f o r Time Cycle Waste C o l l e c t o r ..... 160 Local Exhaust V e n t i l a t i o n a t Opening Hoppers .. . . . 165 Local Exhaust V e n t i l a t i o n - Waste Grinder . . . . . . . . 167 Local Exhaust V e n t i l a t i o n o f Cotton Opening
172 Hoppers ......................................... Exhaust V e n t i l a t i o n and Transport A i r Volumes a t Openings ..................................... 177
Table A.3-8. Local Exhaust V e n t i l a t i o n f o r Cleaning Machines . . 182 Table A.3-9. Local Exhaust V e n t i l a t i o n f o r Card #9. ........... 189 Table A.3-10. S t a t i c Pressure Readings f o r Local Exhaust
Table A.3-11. Local Exhaust v e n t i l a t i o n f o r Card Cleaning system .. ................................ ........ 196
Table A.3-13. Local Exhaust V e n t i l a t i o n a t Spinning Frames ..... 215 Table A.3-14. Local Exhaust V e n t i l a t i o n f o r Wjnding Machines.. .. 222 Table A.3-15. V e r t i c a l E l u t r i a t o r Data ( u g h ) w i t h Overspray -
S i t e 81 ......................................... 227 Table A.3-16. V e r t i c a l E l u t r i a t o r Sampling Data wi th Overspray-
S i t e #2 ......................................... 229 Table A.3-17. A i r F i l t r a t i o n Systems - Component Data .......... 232 Table A.3-18. Reci rcu lated A i r - Tota l Oust Samples ............ 234 Table A.3-19. A i r F i l t r a t i o n Systems - Component Data .......... 236 Table A.3-20. A i r F i l t r a t i o n Systems - Component Data .......... 238 Table A.3-21. Reci rcu lated A i r - Tota l Dust Saqples ............ 239 Table A.3-22. A i r F i l t r a t i o n Systems - Component Data .......... 244 Table A.3-23. Reci rcu lated A i r - Tota l Dust Samples ............ 245 Table A.3-24. A i r F i l t r a t i o n Systems - Component Data .......... 251 Table A.3-25. Reci rcu lated A i r - Tota l Dust Samples ............ 251 Table A.3-26. V e n t i l a t i o n Systems, A i r Cleaning and A i r
Washing Systems - Component Data ................ 256 Table A.5-1. Exhaust V e n t i l a t i o n a t Fecd Table ................ 268 Table A.5-2. Exhaust V e n t i l a t i o n a t Opening Hoppers ........... 273 Table A.5-3. Exhaust V e n t i l a t i o n of Conveyor L i n e ............. 276 Table A.5-4. Exhaust A i r From Cleaning Machines ............... 283 Table A.5-5. A i r Flow Data For Local Exhaust o f Bale Press .... 283 Table A.5-6. A i r F i l t r a t i o n Systems Component Data ............ 286
V e n t i l a t i o n a t Carding .......................... 190
Table A.3-12. Local Exhaust V e n t i l a t i o n f o r Carding ............ 201
x i i
.......---- ~ ~ . . _ . _ . . . . 303
300 Sampling Data ................. ..._......... 302 Sampling Data .................................... P a r t i c l e S ize Data .......................... ~
Sampling Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 308 Sampling Data ............................ .......- 311 p a r t i c l e S ize Data . . . . . . . . . . . . . . . . . . . . . . . . 312 Sampling Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . - 316 Chemical Content Ana lys i s . . . . . . . . . . . . . . . . . . . -. 343
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Table B . l -1 . Table B.2-1. Table 8.2-2. Table 8.3-1. Table 8.4-1. Table 8.4-2. Table B.5-1. Tab le 0.1.
A P P E N D I X A . 1 COTTON C l N N I N G
A . l . O Overview - Process Flow and Exposure Pa t te rns
The in fo rmat ion conta ined in \ t h i s sumary i s d i v i d e d i n t o f i v e func-
t i o n a l process a r e a s i n c o t t o n g inn lng i n which exposure t o c o t t o n dus t
e x i s t s . These func t i ona l process areas are a t seed c o t t o n feeding, seed c o t t o n c leaning, g i n stands, l i n t c lean ing , and the ba le press.
The index o f c o n t r o l techniques and process ing v a r i a b l e s (F igure
A . 1 - 1 ) prov ides the reader w i t h a convenient re fe rence t o appropr ia te
sec t i ons o f i n t e r e s t . The c o n t r o l techniques surveyed a r e l i s t e d above
the appropr ia te f u n c t i o n a l b locks , a long w i t h the process ing v a r i a b l e s
t h a t must be considered when e s t i m a t i n g the e f fec t i veness o f the c o n t r o l s
i n any p a r t i c u l a r c o t t o n g in . The sec t ions o f t h i s r e p o r t i n which the
c o n t r o l s a re discussed i n d e t a i l a re re ferenced.
The modern c o t t o n g i n u t i l i z e s automatic process ing t o remove t r a s h
m a t t e r (hul ls ' , lea f , d i r t , stems, etc.) f rom the seed c o t t o n and t o
separate c o t t o n l i n t f l b e r from the cottonseed. The U . S . g inn ing Indus-
t ry i s loca ted throughout the sun b e l t , s t r e t c h i n g from V i r g i n i a and Nor th Caro l i na south through the M i s s i s s i p p i D e l t a and Texas t o the San Joaquin
Va l l ey i n C a l i f o r n i a . The f o u r m a i n p roduc t i on reg ions can be c l a s s i f i e d as fo l lows:
e Southeast - V i r g i n i a south t o Alabana.
0 Mid-South - Kentucky and M issour i south t o M i s s i s s i p p i and Louis iana.
o Southwest - Texas and Oklahoma.
e west - New Mexico, Arizona, Nevada and C a l i f o r n i a .
P r e l i m i n a r y surveys were conducted i n C a l i f o r n i a , West Texas, and Mid- South g ins i n an e f f o r t t o cover the major d i f f e rences i n c l imate , type
co t ton , and harves t ing methods. D e t a i l e d surveys were completed i n one
M i s s i s s i p p i De l ta g i n and two West Texas g ins .
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Considering there are approximately 2700 active U.S . cotton gins, this assessment included a very small portion o f the industry. Howeve;, through contacts and discussions.with the industry assciciations and USDA
representatives, gins were visited that offered the greatest opportuni!y to evaluate control technology. As this report explains in the descrip- tions o f control techniques, conditions vary throughout the large growing region. l'his includes type of harvesting, trash content in the seed cotton, moisture level, and ambien4! conditions.' Due to thc limitations Qf thls assessment it is not possible! to determine the effectiveness of the control techniques if they were apiilied in all gins.
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The functional operations in cotton ginning can be described as follows:
a Feeding Seed Cotton - Seed cotton is normally delivered to the gin in trailers, from which it is fed pneumatically to the processing operations. Generally, one to three workers operate the suction pipes which take the seed cotton from the trailers to the cleaiing line. Module feeding is a relatively new technology which eliminates the manual suc- tion feeding function.
'
a Drying and Cleaning Seed Cotton - Cleaning machines are used to remove rocks, dirt, stems, leaf and other foreign particles. This "overhead" line usually includes two tower dryers which condition the seed cotton to a moisture con- tent of approximately 6-8 percent. The combinations of type and number of cleaning machines used in different gins vary according to growing regions, types of cotton pro- duced, and operator preference. Figure A . l - 2 illustrates the combinations o f ginning machinery for the plants in Mississippi and West Texas that were included in this pro-
',, ject. The Texas gins process stripper harves2ed cotton
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which c o n t a i n 4 t o 5 t i m e s as much f o r e i g n ma t te r as the
machine p fcked co t tons processed by the Mid-South g in .
0 Ginning - A f t e r the seed c o t t o n i s cleaned, the l i n t f i b e r s
are separated from t h e seed e i t h e r by saw-type or r o l l e r -
type g i n s tand equipment. Since only about 1% of U.S. p l a n t s use r o l l e r g inn ing , o n l y saw g i n s were surveyed.
The g i n saws p r o j e c t between a s e r i e s of meta l r i b s , w i t h
j u s t enough clearance t o p e r m i t c o t t o n f i b e r s t o be drawn through w i thou t a l l o w i n g seed t o pass. The l i n t f i b e r s are a c t u a l l y p u l l e d from the seed whereas the l i n t e r s must be
c u t f rom t h e seed (Sec t lon A.2.0 - Cottonseed Processing). The cot tonseed is mechan ica l l y and pneumat ica l l y t r a n s p o r t - ed t o s torage b ins , f o r eventual t r a n s p o r t t o a cot tonseed o i l m i l l .
0 L i n t Cleaning - The l i n t f i b e r s are pneumat ica l l y conveyed through l i n t c leaners which remove more t r a s h and a p o r t i o n o f ' s h o r t s t a p l e l e n g t h fiber: From one t o th ree l i n t
c lean ing s t a g e s are used, depending upon tho type c o t t o n and the q u a l i t y requirements o f the l o c a l market.
0 Ba l i ng - A f t e r l i n t c lean ing the l i n t f i b e r i s pneumat-
i c a l l y conveyed t o a condenser/separator where i t i s formed i n t o a bat . Oo f fe r r o l l s remove the b a t from the condenser drum, a l l ow ing the c o t t o n t o f a l l down a l i n t s l i d e i n t o the
ba le press. The ba le press h y d r a u l i c a l l y presses t h e co t -
t on i n t o ba les weighing approx imate ly 480-500 pounds. The
packaged ba le i s then removed f r o m the press and conveyed
t o the s t o r a g e l oca t i on .
Based on the i n fo rma t ion ob ta ined i n the p l a n t s surveyed du r ing t h i s
p r o j e c t and f r o m o t h e r a v a i l a b l e sources, the p o t e n t i a l f o r exposure o f
workers i n g i n n i n g i s cha rac te r i zed below. This data i s i n d i c a t i v e o f the poss lb le b e n e f i t s o f c o n t r o l technology i n reducing the dus t expo- sure o f the worker popu la t i on i n c o t t o n g inn ing .
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Workers Exposed Est imated I n d u s t r y Average p e r / S h i f t To td l @ 2700
Work Area per g l n surveyed g i n p l a n t s
Feeder Operator 3 . 3 3 Gin Stand Operator 1.67 L i n t Cleaner
Opera tor/Sweeper 1.00 Bale Press Operator* 2.00
.67 s&llple Man** - T o t a l s 8.67
16.200
5,400
37,800
Cotton harves t ing and g lnn ing i s a seasonal funct ion whlch l a s t s 6 t o 12 weeks each year. A lso , s ince the m a j o r p o r t i o n o f t h e c rop i s ginned i n 4-6 weeks, the second 12 hour s h i f t i s normal ly needed only du r ing t h i s
per iod. S ince
the turnover r a t e i s a lso h igh, severa l a d d i t i o n a l employees a r e u s u a l l y kep t on standby and used when needed.
A.1.1 Seed Cotton Feeding
Some g ins operate o n l y one s h i f t throughout t h e season.
. .
A . l . l . l Module Feeding (Process Con t ro l )
I n a convent ional c o t t o n g i n , f i e l d c o t t o n i s f ed pneumat ica l l y t o the g i n processes a t the suc t i on shed. Th is j o b f u n c t i o n requ i res two t o fou r employees t o move the t r a i l e r s i n t o p o s i t i o n and t o operate the l a rge suc t i on p ipes t h a t t r a n s p o r t the seed c o t t o n t o the c lean ing l i n e . The module feeding system (F igu re A. l -3 ) e l im ina tes the manual feed ing o f f i e l d c o t t o n a t the suc t i on shed and prov ides a constant f l o w t o the g inn ing process. Mon i to r i ng of the feeding a r e a can be done w i t h a c losed c i r c u i t T .V . screen loca ted a t the g i n stand c@nsole. This enables the
worker t o be removed from the suc t i on feed opera t ion and the t ime weighted
average exposure a t t h i s l o c a t i o n t o be reduced. - - Two g i n s had automatic presses w i t h one operator , one g i n had a manual press w i t h four operators .
** One of the g ins d i d n o t do sampling.
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! . . FIGURE A . l - 3 . MODULE FEEDING SYSTEH
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However. implementation of this process requires capital investment in new module feed hdrVeSting and feeding equipment. This Change could canpletely phase out the use of conventional seed cotton trailers and manual suction shed feedlng.
A.1.1 .2 Suction Shed Feeding - Personal Protection Devices
The feeding o f field cotton at a suction shed process requlres the worker to Stand inside a wagon and operate a suction pipe which picks up the seed cotton and transports it to the cleaning machines. The nature o f
this equlpment makes the use of englneering controls impractical. Since engineering controls cannot be utilized, respirators must be used i f It i s
necessary to provide workers with personal protection against potential exposure to cotton dust emissions.
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A . 1 . 2 Ginning
Con t ro l assessed: A.1.2.1 Exhaust V e n t l l a t i o n d t Feeders (Engineer ing
Con t ro l )
The e f f e c t l v e n e r s of con t ro l w l t h t h i s v e n t i l a t i o n syrtein was evalu- a ted s lmu l tdneour ly wlth t h e a p p l i c a t j o n o f an overspray (X-78). de- scribed i n Sec t ion A.1.2.2. V e r t l c a l e l u t r l a t o r s were p o s i t i o n e d dpprox-
ima te l y th ree f e e t fran the feeders t o o b t a i n samples a t the emissfon
source. The r e s u l t l n g data l l s t e d below i n d l c a t e a r e d u c t i o n i n dust
l e v e l s wl th the v e n t i l a t i o n system operat lng.
V e r t i c a l E l u t r i a t o r Cot ton Dust Leve ls (ug/m )
. Sample Date -. 12/14/78
No. V e r t l c a l E l u t r f a t o r Samples Mean Std. Dev. Range
1. With a l l c o n t r o l s 3 1147 - 960 1360 1120
Sample Set N X (I L o w u!!. Median - operat ing
2. Wi th l oca l exhaust 3 1940 - 1780 2200 1840 v e n t i l a t i o n turned o f f and o ther c o n t r o l s opera t ing
The processing Var iab les p a r t i c u l a r t o t h i s ope ra t i on are as
fo l l ows :
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Var iab les I n f l u e n c i n g Con t ro l E f fec t i veness
1. Type o f Cotton:
December, - 1978
Geographic Region west Texas Harvest Method S t r i p p e r Trash Content 34-41%
2. Ambient Cond i t ions : 12/14/7a 12/15/70 Wind Speed and D l r e c t l o n 8 mph SW 10.4 mph NU R e l a t i v e Humid i ty 37% 3 39.2% Ambient A i r Dust l e v e l s - Upwind 230 - Downwind 850 ug/m
3. Product ion Var iab les: Product ion Ra te Adjacent Process Dust Sources E x t e r ( o r Cyc 1 ones
4.G - 10.8 b d l e s l h r L i n t s l i d e , l i n t c leaners Downwind of g i n b u i l d i n g
The use of exhaust v e n t l l d t l o n a t the b o t t a n r e d r panel of the Super
M l t c h e l l feeders (F igu re A . l - 4 ) reduces thc 2xt:sion o f dus t to the woik-
p lace a i r . O r i g l n a l l y t h i s feeder was designed t o In t roduce humld l f i ed
a i r a t t h e top o f the feeder t o reduce s t a t i c charges and mols ten the c o t t o n f i b e r t o improve t h e separa t ion o f l i n t from seed a t the g i n stand.
P a r t o f the system i s t h e exhaust duc t t h a t was connected t o t h e base of the feeder t o a s s i s t i n more thorough ly app ly ing the humld a i r .
The humid a i r system i s n o t now being used s ince the p l a n t s t a r t e d us ing the overspray (Sec t i on A.1.2.2) t o improve g inn ing . However, s ince
the g i n operators observed improved dust l e v e l s w i t h the v e n t i l a t i o n
system operat ing, i t I s s t l l l be ing used t o exhaust a i r through .the feeder.
The v e n t i l a t i o n system i s designed w i t h a 6" exhaust take o f f mounted f l u s h t o the lower rea r panel o f the feeder. Th is 6" duct i s then cocnected t o a tapered duc t system s ized f o r proper balance a t each branch. The a i r f l ow a t the feeders ranged from 680-741 CFM through the
f o u r 6" exhaust ducts. Th is volume o f a i r had a p o s i t i v e e f f e c t on removing dust, based on the measurements made du r ing t h i s w r v e y .
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Cont ro l assessed A.1.2.2 A p p l i c a t l o n of L i q u i d Overspray (X-78) (Eng incer lqg C o n t r o l )
Dur ing the assessment o f t h i s c o n t r o l technique the f o l l o w i n g dust
level : were observed i n the g i n stand, ba le press, and seed scale areas:
V e r t i c a l E l u t r i a t o r Samples (ug/m3)
Smp le Date - 12/14/78 No.
Smp les Mgan Std. Dev. Sample S e t N X 0 --
1. With X-78 6 952 560 293 1457 1037 45
2. Without X-78 6 1723 832 817 3217 1559
The dust data obta lned w l t h t h l s cont ro l technique demonstrates a r e d u c t i o n I n dust l e v e l s w l t h t h e add i t i ve . The process ing v a r i a b l e s
p a r t i c u l a r t o t h i s opera t lon .are as f o l l o w s :
Var iab les I n f l u e n c i n g Cont ro l E f fec t i veness D e s c r i p t i o n
1. Type o f Cotton: Geographlc Region Harvest Method Trash Content
West Texas Stripper 34-41%
2. Amblent Condi t ions: 12/14/78 12/15/78 Wind Speed and D i r e c t l o n 8 mph SW 10.4 mph NW R e l a t i v e Humid i ty 37% 39.2% Amblent A i r Dust Levels - Upwind 230 iig/m3
- Downwind 850 ug/m
3. Product ion Var iab les: Product ion Rate Adjacent Process Dust Sources
E x t e r i o r Cyclones
4.6 - 10.8 ba les /hr L in t : s l i d e . l i n t
Downwind o f g i n c leaners
bu i 1 d 1 ng
The d e s c r i p t i o n o f t h l s eng lneer ing c o n t r o l 1 s as fo l l ows :
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A l i q u i d a d d i t i v e ( X - 7 8 ) i s sprayed on the seed c o t t o n before g inn ing
t o reduce s t a t i c e l e c t r i c i t y and t o Improve the separa t ion of l i n t fran
the seed a t thc g i n stands. Another reason f o r us ing the a d d i t i v e was t o improve dust l e v e l s i n the g i n work weds. The r e s u l t s of t h i s s tudy
showed a reduc t i on i n dust emission based on t h e v e r t i c a l e l u t r l a t o r
measurements.
The system sprayed approx imate ly 4 ounces o f a d d i t i v e per ba le o f c o t t o n a f t e r t h e second tower d r i e r . Th is helped the a d d i t i v e t o be as
u n i f o r m l y d i s t r i b u t e d as pos?>ib le on the seed c o t t o n be fore g inn lng and
reduces emissions from ginning. l i n t c leaning, ba l i ng . and seed sca le
operat 1 ons.
A poss ib le e f f e c t o f us ing t h e a d d i t i v e t o c o n t r o l dus t emissions i n g inn ing cou ld be increased emissions i n downstream processes. Th is has n o t been evaluated p r e v i o u s l y and i s inc luded i n t h e recornendat tons for research.
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A.1.3 Ba l lng .
Cont ro l assessed: A.1.3.1 A p p l i c a t i o n of Humid A i r a t L i n t S l i d e (Process Cont ro l )
Cot ton grown i n the d r i e r c lmates such as West Texas has excess ive ly
low mois tu re leve ls , and a f t e r g i n n i n g . m o i s t u r e i s added t o the l i n t
f i b e r . The technique o f f o r c i n c humid a i r i n t o the l i n t c o t t o n underneat':
the l i n t s l i d e was evaluated t o es t imate t h e c o n t r i b u t f o n toward dus t c o n t r o l i n t h e g in . The v e r t i c a l e l u t r i a t o r s were pos i t i oned approx i -
mate ly two f e e t f r o m the l i n t s l i d e t o o b t a i n samples a t the emission
source.
3, V e r t i c a l E l u t r i a t o r Samples (vg/m
Sample Date - 12/12/78
No. V e r t i c a l E l u t r i a t o r Samples Mean Std. Dev. ~ Ran ". ; e d .
. Sample Set N X 0 IJ- e i a n -- Without Mo is tu re 3 1743 - 1440 2010 1780
With Mois tu re 3 983 - 560 1320 1070
The dust l e v e l s observed show a reduc t i on i n c o t t o n dus t emission
when th is method of app ly ing h u m i d i f i e d a i r i s used, compared t o when no humid a i r I s be ing appl ied. The process ing va r iab les p a r t i c u l a r t o t h i s
ope ra t i on are as f o l l ows :
Var iab les I n f l u e n c i n g Contro l E f fec t i veness December, 1978
. .
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1. Type o f Cotton: Geographic Region H a r v e s t Method Trash Content
West Texas S t r i ppe r 12-44%
2. Ambient Condi t ions: i211217a 12/13/78 Wind Speed and D i r e c t i o n 9.6 mph SW 12 mpli NW R e l a t i v e Humid l ty 40% 32% Ambient A i r Dust Levc ls - Upwind 84 u g h - Downwind 890 ug/m
3 . Product ion Var iab les: Product ion Rate Adjacent Process Uust Sources
E x t e r i o r Cyclones Downwind
12.1: - 15.4 ba les /hr G in stands and l i n t
c leaners
A d e s c r i p t i o n o f the c o n t r o l technique i s as fo l l ows :
Besides conveying t h e c o t t o n t o t h e ba le press, t h e l i n t s l i d e I s used t o r e - c o n d i t i o n the l i n t f i b e r s w i t h mois ture. The h i g h p r o p d r t i o n o f f o r e i g n p l a n t ma t te r i n the f i e l d c o t t o n a lso conta ins a g rea ter amWlnt o f mo is tu re (up t o 20-25%) than does t h e c o t t o n l i n t . Whi le the tower
d ryers reduce the o v e r a l l mo is tu re conten t i n t h e f i e l d c o t t o n t o l ess than lo%, i t a lso reduces t h e mois tu re conten t o f the l i n t t o (1-5%.
Mo is tu re i s added t o the c leaned seed co t ton a t the feeders and a t the
l i n t s l i d e t o ge t the des i red 6-8% mois tu re content i n the f i n i s h e d bale. I t i s r e a l i z e d t h a t t h i s a d d i t i o n o f mois ture a t the l i n t s l i d c i s a
process ing technology no t app l i ed d i r e c t l y t o c o n t r o l c o t t o n dust; how- ever, mois ture does have a d i r e c t e f f e c t on the h a r d l i n g o f c o t t o n f i b e r
and the amount o f ma t te r t h a t becomes a i rborne.
The l i n t s l i d e a t t h i s p l a n t was approx imate ly 18 f e e t i n lencith by
54" wide. The bottom o f the l i n t s l i d e (F igure A . l - 5 ) has a l!. f o o t
louvered g r i d system where humid a i r i s blown i n t o the b a t o f co t ton .
Inc luded i n t h i s design i s a duc t t o s l i d e attachment, 10" diametei. duct
work, a g a s - f i r e d humid a i r u n i t and water supply. The 10" main duc t
feeds humid a i r i n t o the bottom o f the l i n t s l i d e . The volume r i i a i r moving i n t o the l i n t s l i d e g r i d measured 210 cub ic f e e t per minute. !'his
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r e l a t i v e l y low q u a n t i t y o f h u m i d i f i e d air c o n t r o l s the amount o f mo is tu re
added. A l s o , s ince i t i s in t roduced a t a slow v e l o c l t y , emissions from
the l i n t s l i d e a r e prevented. The a i r a l s o provfdes a cushion on which
the l i n t t r a v e l s w h i l e f a l l l n g down the s l i d e . The f l n a l mo is tu re conten t
i s 6 4 % i n the cot ton l i n t . Approx imate ly 30 lbs o f of wate r per ba le i s needed f o r t h i s system.
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t , . . . . , . . . . . 1 ... I .,:..,:r. ~ . .. . . . . . . . . .-. _.. -
4 . I
I ..
I .
f I .
Con t ro l assessed: A.1.3.2 Local. Exhaust V e n t l l a t i o n a t L i n t S l i d e
(Engineer ing Con t ro l )
When t h l s System WdS evaluated d Chef7lfCdl c o n d i t i o n e r (X-78) WdS
app l ied ds an oversprdy t o the seed c o t t o n (Sec t ion A.1.2.2). Dur ing t h i s
dssessment a l l c o n t r o l techniques, i n c l u d i n g the use o f chemical con- d i t i o n e r , the humid a i r system and t h e v e n t i l a t i o n system were In operd-
t i o n . The v e n t i l a t i o n system was t h e o n l y c o n t r o l tu rned o f f du r ing t h i s
assessment. The v e r t i c a l e l u t r i d t o r s were p o s i t l o n e d dpproxlmately two f e e t from the l i n t s l i d e . The sampling data i s l i s t e d below:
V e r t i c a l E l u t r i d t o r Cot ton Dust Leve ls ("g/m ) -
Sample Date - 12/15/78 No. * Vert i c a l E l u tr 1 a t o r Samples Mean Std. Dev.
1. Wi th d l 1 c o n t r o l s 2 413 - 293 533
- Sample Set N X 0 - operat ing
2 . With local exhaust 2 1295 - 1004 1585 v e n t i l a t i c n turned o f f
The r e s u l t s show a s i g n i f i c a n t reduc t i on i n dust l e v e l s w i t h t h e
The process ing v a r i a b l e s p a r t i c u l a r local exhagst v e n t i l a t i o n equipment. t o t h i s opera t ion are as fo l lows:
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L -
I J
Var iab les I n f l u e n c l n g Cont ro l E f fec t i veness D e s c r i p t i o n
1. Type of Cotton: Geographic Region Harvest Method Trash Content
West Texas Str ipper 34-41%
. . 2. Ambient Condi t ions: 12/14/78 i 2 i i j i i 6 Wind Speed and D i r e c t i o n 8 mph SW 10.4 mph NW R e l a t i v e Humid i ty 37% 3 39.2% Ambient A i r Dust Leve ls - Upwind 230 u g h 3 - Downwind 850 bg/m
3. Product ion Var iab les: Product ion Rate Adjacent Process Oust Sources
E x t e r i o r Cyclones
4.6 - 10.8 ba les /hr L i n t s l i d e , l i n t
Downwind o f g i n c ieaners
b u i l d i n g
4. A d d i t i o n a l Cont ro l Technfques: A p p l i c a t i o n o f Humid A i r a t L i n t S l i d e Descr ibed i n
A p p l i c a t i o n o f L i q u i d Overspray Sec t ion 1.3.1
Sec t ion 1.2.2 Descr ibed i n
Th is c o n t r o l technique is descr ibed below:
Whi le the c o t t o n l i n t s l i d e s down the l i n t s l i d e t o the ba le press,
humid i f i ed a i r i s in t roduced through a louvered g r i d ,system on the bottom
o f the l i n t s l i d e . Th is g i n was exper ienc ing a problem w i t h t h i s a i r b lowing l i n t i n t o the a i r and c o l l e c t i n g on the c e i l i n g and r a f t e r s . I n
order t o c o r r e c t t h i s problem and e l i m i n a t e the need t o c lean overhead f requent ly , a canopy hood (F igu re A. l -6) was i n s t a l l e d over the l i n t
s l i d e . Th is v e n t i l a t i o n hood i s suspended two f e e t above t h e 45' angled l i n t s l i d e approx imate ly th ree f e e t f rom the ba le press and exhausts l i n t and c o t t o n dust t o e x t e r i o r cyclones.
The dimensions o f the tapered canopy hood are 4.5' x 4.5' and the
duct work was 20" i n diameter. V e l o c i t y readings were taken t o record a i r
f l o w a t t h e t ime o f the sampling. The duct v e l o c i t y measured by p i t o t t rave rse was 3420 feet /minute w i t h a volume o f 7462 CFly o f a i r . Face
v e l o c i t y readings taken around the per imeter of the hood ranged from 200
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. ~. . .~ - . .. .
1
F I G U R E A . l - 6 . EXHAUST V E N T I L A T I O N AT L I N T S L I D E
-57-
t o 450 f t . / n l n . Capture v e l o c i t i e s ranged from 76-140 :t./mln. a t 6" from the hood system, and were below 50 f t . /min. a t the l i n t s l ide .
However, dur ing t h i s assessment. the hood connectlon t o the m a i n
exhaust duct WdS p a r t i a l l y dislodged and the e f f e c t i v e Capture v e l o c i t y
was decreased. Repalr ing the hood would f u r t h e r reduce dust l e v e l s a t
t h t s l i n t s l i de . Also, lowering the hood as c lose .as p o r s f b l e to the l i n t s l i d e wi thout p l c k i n g up c o t t o n f i b e r would improve c o n t r o l over emis- s i o n s .
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Cont ro l assessed: A.1.3.3 Process I s o l a t i o n f o r F i xed Eor Edle Press
(Process Equipment)
This modern automatic ba le press was inc luded i n the assessments
descr ibed i n Sect ions A.1.3.1. A p p l i c a t i o n o f Humid A i r a t L i n t S l i d e and
Sect ion A.1.4.1. Local Exhaust V e n t i l a t i o n a t Seed Scale ( S i t e 11). The v e r t i c a l e l u t r i a t o r s were p o s i t l o n e d th ree t o f o u r f e e t from the ba le
press. The c o t t o n dust measurements observed i n d i c a t e the l e v e l o f con- t r o l achieved i n t h e ba le press a rea .
3 V e r t i c a l E l u t t f a t o r Samples (ug/m 1 Sample Date - 12/13/78
Wi thout Seed Scale H f t h Seed Scale Sample Locat ion Exhaust V e n t i l a t i o n Exhaust V e n t i l a t i o n
Underneath main f l o o r '
a t seed scale and bale press 5070 1457
idl th Mois tu re Without Mo is tu re
Main f l o o r a t l i n t s l i d e - b a l e press 983 1743
The process ing vdriab:eS encountered du r ing the survey a r e a s fo l l ows :
-,. . . _ . I. . . . . .. .
I ..'
. . .: i . .
. 5 *
Variab!es i n f l u e n c i n g Cont ro l E f fec t i veness
1. Type of Cotton:
December, 1978
Geographic Region West Texas H a r v e s t Method S t r i p p e r Trash Content 12-443
2. Ambient Condi t ions: 12/12/78 12/13/76 Wind Speed and D i r e c t l o n 9.6 mph SW 12 mph NW R e l a t i v e Humldi tp Ambient A i r Dust Levels - Upwind
32% 3 - Downwind 890 ug/m
84 ug/m
3. Product ion VdrldbleS: Produc t ion R a t e 12.2 - 15.4 ba les /hr Adjacent Process Dust Sources C fn stands and l i n t
E x t e r l o r Cyclones c leaners
Downwind
The purpose of t h i s process equipnent be ing i n s t a l l e d i s t o improve p r ,oduc t i v i t y through automation of t h e d i f f e r e n t s teps i n forming a ba le
of co t ton . The press ing o f the c o t t o n i s accomplished under the main f l o o r l e v e l , thus i s o l a t i n g t h i s p a r t o f t h e press. A s a r e s u l t . dus t p a r t i c l e s emi t ted when the ram presses the c o t t o n (F igu re A.1-7) are no t discharged d i r e c t l y i n t o the workplace a i r . In add i t i on , the automat ic s t rapping, ba le removal and bagging opera t ions make i t poss ib le t o reduce
the number o f workers exposed t o c o t t o n dust.
3
-E3-
I -_. .......
-6 1-
A.1.4 Seed Scale
Cont ro l assessed: A.1.4 .1 Loca l Exhaust V e n t l l a t i o n a t Seed Scale
(Engineer ing Cont ro l )
The eva lua t ions o f th is engineer ing c o n t r o l technique a t two c o t t o n
g ins showed the f o l l o w i a g l e v e l s o f c o t t o n dust c o n t r o l :
V e r t i c a l E l u t r i a t o r Samples (pg/m3)
With Exhaust Without Exhaust Samples Vent i 1 a t i on Vent i 1 a t i o n
S i t e 6 1 5,070 17,270
S i t e # 2 1,457 1 .861
The v e r t l c a l e l u t r i a t o r samples were taken two, f e e t from t h e seed scales and showed reduc t i ons i n c o t t o n dust emissions a t b o t h g i n Si tes w l t h the v e n t i l a t i o n systems. The seed scales a t bo th s i t e s were p o s i -
t i oned below the main f l o o r l e v e l t o i s o l a t e them from the remain ing g lnn ing processes. As a r e s u l t , the use o f l o c a l exhaust v e n t i l a t i o c I n
these g ins had no e f f e c t on reduc ing dust concent ra t ions i n the main workplace. However, i n g ins where a seed scale i s loca ted on the main
f l o o r l e v e l , improvement i n t h i r dust l e v e l can be made w i t h t h e l o c a l
exhaust v e n t i l a t i o n .
The processing v a r i a b l e s p a r t i c u l a r t o each opera t ion a r e as
fo l lows:
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1 I
t i !
1. :jpc o f Co:can: tcogva?ntc Qegton Hirvest Xethod Trash Content
ueit Tenas UeiC l e r r i Strlpver Scr l p p i r 34-41X 12-44X
I2 I12178 IZIl J/?S Ytnd Speed and Olrecclon 8 rnph SU 10.4 ngh M 9 . 6 mph SU 12 9 h XE RelaClve Hunldlty
2 . h b l e n c Condltlonx: i z i i 4 1 i e i z i i s i I B
31x 19.21 40% 13% h n b l e n t Alr Oust L e v o l s - Upwlnd 230 ugtm] a4 " q i m - Oomwlnd 850 r g t m 890 u g h
1. Production Varliblei: Prodiic t I on Race Adjacent Process Oust Sources E rterlor Cyclones
4.6- 10.8 b d l a s l h r 12.2-15.0 b a l d h r Bale press ._ D o r r w l n d Oowwlnd
A d e s c r l p t l o n o f each c o n t r o l f o l l o w s :
S i t e $1
The seed sca le I s a major source o f c o t t o n dus t emissions f o r two reasons. The c o t t o n seed i s t ranspor ted from each g i n s tand by a mechanical auger feed, as opposed t o a pneumatic system, and the seed i s dropped from the conveyor on an open seed scale. This a c t i o n o f dropping
t h e seed onto the scale causes dus t t o be discharged from t h e scale.
A t S i t e # l , ' t w o techniques were used t o reduce the amount o f c o t t o n dus t emi t ted by the seed scale i n t o the workplace a i r . F i r s t , the sca le
was moved underneath the main floor l e v e l i n a roan w i t h the b a l e press t o
i s o l a t e the dust source from the areas where workers spend t h e i r t i m e . Secondly, a l o c a l exhaust v e n t i l a t i o n system (F igure A. l -8) was i n s t a l l e d t o exhaust c o t t o n dust generated by the mechanical t ranspor t of seed and dropping i t onto the scale.
A 25" x 30" opening was c u t i n the back o f the seed scale t o accom- modate the 9" x 30.5" x 33.5" hood system. A 12" duc t was connected t o
the top o f the taper t o exhaust a i r . Both s ide panels o f the seed scale
were removed t o a l l o w adequate make up a l r t o the system. When necessary
t o r e c y c l e seed c o t t o n t h a t c o l l e c t s i n the ove r f l ow b in , the 12" duc t
i I
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FIGURE A . l - 8 . LOCAL EXHAUST VENTILATlON AT SEED SCALE - SITE # I
10 w i o c n
,i . . -64-
would be removed f r o m the connect ions t o the seed scale hood. However,. ! t h i s occurred o n l y 7% o f the t ime sampling was done.
The a i r volume exhausted through the 12" main duct was 2055 CFM and
the a i r v e l o c i t y was 2617 f t . / m i n . The face v e l o c i t y readings ranged from
50 t o 425 f t . /m in . around the 20" x 30" s ide panel openings o f the seed
s c a l e housing. Also, the opening t o t h e auger conveyor i s a t h i r d source
o f make up a i r f o r the s u c t i o n hood. The area o f t h i s opening I s 10.5% of the t o t a l open face a rea o f the seed s c a l e housing. A i r f l o w measurements
taken a t t h i s p o i n t showed a f a c e v e l o c i t y o f 175 f t . /m in . Al though the
system was n o t designed t o s p e c i f i c a l l y c o n t r o l dus t generated i n the
auger conveyor, a negat ive pressure i s mainta ined i n the conveyor. A s a r e s u l t , dust generated I n s i d e the conveyor i s exhausted through the seed
sca le t o the. hood, The plenum design i s i l l u s t r a t e d i n F lgu re A.l-8, a long w i t h corresponding a l r f l o w measurements.
The i n s t a l l a t i o n o f t h i s seed scale i n a room below t h e f i r s t f l o o r
I s o l a t e s i t from the main work area and i s unique. Few c o t t o n g ins have a basement s ince ' the common c o n s t r u c t i o n i s poured concrete on grade. Al though dust exposure i s improved the re are sane drawbacks w i t h t h i s under f l oo r i n s t a l l a t i o n . Maintenance i s increased due t o v i s u a l inacces.. s i b i l i t y and energy requirements a re increased t o r a i s e the seed from the basement f l o o r t o t h e seed hopper.
The excessive dust l e v e l s i n the room w i t h the bottom o f the b a l e
press and the seed scale he lps i l l u s t r a t e the excessive amounts o f c o t t o n dus t p a r t i c l e s t h a t are en t ra ined i n s t r i p p e r harvested co t tons . The
r e s u l t s do i n d i c a t e t h a t a very s i z a b l e amount o f f i n e dust i s be ing e l im ina ted from the f i r s t f l o o r workplace a i r w i t h the i s o l a t e d l o c a t i o n s and the a p p l i c a t i o n o f exhaust v e n t i l a t i o n .
S i t e # 2
The scale f o r automat ic weighing a t t h i s g i n p l a n t was a l s o pos i -
t i oned i n a room underneath the main f l o o r o f the g i n . The duct f o r
t r a n s p o r t o f cot tonseed t o the sca le was i n s t a l l e d a t the top o f t h e seed
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..
scale enclosure (F igure A. l -9) and an exhaust hood was mounted on the back
side. Th is l o c a l exhaust system main ta ined an a i r f l o w o f 102 CFM through the top duct where seed en ters and 475 CFM/sq. f t . o f face area a 1 the
open f r o n t panel. Make up a i r was p rov ided t o t h i s enclosed space through
a 2 ' x 3 ' opening i n the f i r s t f l o o r . Th is system c o n t r o l l e d dust gener- ated from t h e auger t r a n s p o r t system as w e l l as when the seed was depos-
i t e d on t h e scale. Also, the l o c a t i o n o f the seed sca le i so la te - . the
process f rom employees working on t h e main f l o o r l e v e l and reduces ( lust
exposure.
The dimensions o f t h e seed sca le hood were 17" w id th x 9" depth x 34"
he igh t . The dimensions o f the exhaust hood centered a t t h e back o f the seed scale were 12" x 30" x 5". The hood i s connected t o a taper and exhausted through an 8" duct . A i r v e l o c i t y measurements showed an average face v e l o c i t y o f 475 f t . /min. The duc t v e l o c i t y was 3695 f t . /m in . w i t h an
a i r voiume o f 1290 CFM. The system cou ld be mod i f i ed t o i nc lude a b l a s t
gate i n t h e main duct p r i o r t o t h e f a n f o r adjustment o f i i r f l o w a t t h e
seed scale enclosure. A p r o v i s i o n should be made f o r l o c k i n g the damper
a f t e r the ba lanc ing has been performed.
A d d i t i o n a l v e n t i l a t i o n i n t h e room i s prov ided by an 11" duct, pos i -
t i oned approximately 2" lbove f l o o r l e v e l t o capture dust and f l y t h a t f a l l s t o t h e f l o o r . and
the exhaust a i r volume was 2070 CFM (F igu re A . l -9 ) .
The a i r v e l o c i t y i n the duct was 3137 f t . /m in .
Improvements cou ld be mddE t o t h i s v e n t i l a t i o n system i n two ;.,'iys. The r e s t r i c t i o n o f make-up a i r reduces the e f f i c i e n c y o f v e n t i l a t i o n a t
t h e seed scale. Disconnect ing the f l o o r exhaust duc t w i l l pe rm i t more a i r f l o w i n t o the seed sca le enc losure and improve c o n t r o l a t the emission source. Observat ions a t the seed scale i nd i ca ted excessive dust ern is- s ions s t i l l come from t h i s opera t ion .
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1.
FIGURE A.1-9. LOCAL EXHAUST VENTII .ATION AT SEED SCALE - S I T E # 2
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A.1.5 G in P l a n t Design
Process Systems assessed: A.1.5.1
A.1.5.2 A.1.5.3 A.1.5.4
A.1.5.5
A.1.5.6
A.1.5.7
A.1.5.8
Make-up A i r In takes
Cyclone Locat ions
Locat ions o f M a t e r i a l Handl ing Fan
P a r t i t i o n i n g
Work-Stat ion I s o l a t l o n
Automat ic Overf low Recycl i n g
L l n t Cleanlng Process A i r F low Automat ic Bale Handl ing Equipment
The cons t ruc t i on o f t h e g i n b u i l d i n g and t h e p l o t p l a n f o r p l a c i n g machines and fans were designed t o p rov ide f o r c o n t r o l o f dus t exposure. The g i n takes advantage o f inherent opera t ing parameters t o p rov ide con- t r o l over dust emissions i n the work areas. F igu re A.l-10 i s a p l o t p lan which can be referenced t o du r ing t h e d iscuss ion on t h l s g in . The v e r t i -
c a l e l u t r i a t o r s were p o s i t i o n e d t o o b t a i n samples t h a t would be repre- sen ta t i ve o f worker exposure. The r e s u l t i n g c o t t o n dust sampl.lng data i s o u t l i n e d below:
P COTTON OUST SAMPLING ( pg/m3)
9 202 68 I15 149 119 3 500 49 446 517 511
9 289 12 211 190 Z J S I 480 119 181 619 419
M 101 76 115 515 3M 9 594 251 i n i 1771 142
FIGURE A.l-10. PLOT PAN OF NEW GIH
3
door stays open
suctlon shed
I
I
Loading
Dock
2
oroceir inq Eoulpwnt Key:
1. Suctlon Sked 9 . l n c l l n e d Cleaner 2 . " B l q J" Machlne IO. O l r t r l b u t o r 3 . Tower Gryer 11. Feeder J. l n c l l n e d Cledner: 1 2 . Gln Scar,< 5 . St lck Nachlne 1 3 . 1 s t Stage L l i t Cleaner 6 . St lck Hacklne 1 4 . 2nd Stage L f n t Cleaner 7 . 'Incuum Omooer 1 5 . L l n t S l l d e 8 . Tower O v e r 16. Bale Press
These c o t t o n dust data i n d i c a t e t h a t a s u b s t a n t i a l l eve l o f c o n t r o l
can be achieved i n a g i n p r o p e r l y l a i d out and operated under the cond i - t i o n s found i n t h i s c o t t o n growing reg ion . The process ing v a r i a b l e s
p a r t i c u l a r t o t h i s p l a n t w e r e as f o l l o w s :
Var iab les I n f l u e n c i n g Cont ro l E f fec t i veness
1. Type o f Cotton: Geographic Region Harvest Method Trash Content
2. Ambient Condi t ions: Wind Speed and D i r e c t i o n f i e l a t i v e Humid i ty Ambient A i r Dust Leve ls - Upwind - Downwind
3 . Product ion Var iab les: Product ion Rate Adjacent Process Dust Sources E x t e r i o r Cyclones
4 i . A d d i t i o n a l Cont ro l Techniques:
D e s c r i p t i o n
M i s s i s s i p p i D e l t a Sp ind le Picked 32%
11/7/79 5 mDh SW 57%' 53 791 pg/m
15 b a l e s l h r G in stands Downwind
Process A i r Exhaust - B a t t e r y .Condenser M a t e r i a l Transpor t Fan Layout
The processing parameters used i n des ign ing the g i n t o p rov ide con-
t r o l over dust emissions are descr ibed below:
A.1.5.1 Make-UD A i r In takes
The g i n b u i l d i n g i s cons t ruc ted w i t h the f r o n t f a c i n g the p r e v a i l i n g southwest winds. This a l lows a i r t o en te r through the f r o n t o f the g i n and be exhausted through duct work t o the e x t e r i o r cyc:ones downwind (Nor theast ) of the b u i l d i n g . The f r o n t suc t i on shed employs a canopy r o o f
t o she1t.r the pneumatic suc t i on opera t ion and concentrate makeup a i r through one wa l l opening on th i s s i d e o f the b u i l d i n g .
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This des ign a l lows makeup a i r t o en te r the p l a n t through the top of
the f r o n t w a l l . The doors a re kept c losed and c ross d r a f t s and tu rbu lence
are reduced.
A . 1 . 5 . 2 Cyclone P o s i t i o n i n g
T h i r t e e n Fans are loca ted i n the g i n f o r t r a n s p o r t i n g seed c o t t o n and e x p e l l i n g t rash t o the e x t e r i o r cyclones a t the r e a r of the b u i l d i n g . The
e f f e c t o f des ign ing the g i n t o exhaust t r a s h t o the NE s i d e takes advan-
tage o f the p r e v a i l i n g wind t o min imize reentra inment b y a l l o w i n g f ine dus t t o be blown away f rom the b u i l d i n g . Our ing the survey two v e r t i c a l e l u t r i a t o r s were p o s i t i o n e d ou ts ide the g i n t o sample ambient a i r . The
upwind sampler recorded dus t l e v e l s o f 53 ,,g/m For a i r be ing supp l ied t o the p l a n t . The V.E. sample obta ined downwind o f the g i n was p o s i t i o n e d a t t h e base o f t h e cyclones and l i n t c leaner exhaust and recorded amblent
dust l e v e l s o f 7Y1 u g / m .
3
3
This range o f p a r t i c l e s sampled demonstrates t h e importance of
cyc lone placement t o min imize r e e n t r a i m e n t o f dus t and t r a s h m a t e r i a l exhausted from t h e g in . Th is g!n uses approx imate ly 104,700 CFM of a i r f o r pneumatic t r a n s p o r t systems. Ambient a i r concent ra t ions can have a s i g n i f i c a n t e f f e c t on r a i s i n g workplace dus t leve ls .
A . 1 . 5 . 3 Locat ion of M a t e r i a l Handl ing Fans
A l l p rec lean ing equipment and a m a j o r i t y o f the m a t e r i a l conveying fans (F igu re A.l-10) are located i n the northwest corner of the b u i l d i n g .
The i n c l i n e d c leaners and s t i c k machines remove the hea*vy d i r t and t r a s h and can be major c o n t r i b u t o r s t o dust emission. The m a t e r i a l t r a n s p o r t fans i n t h i s process area use approximately 20,000 CFM o f a i r taken from i n s i d e the g in . A i rborne dust from t h e c iean ing equipment i s exhausted i n
t h i s a i r supp l ied t o the fans. This process space occupies a volume o f 37,200 cubic f e e t and receives 32 a i r exchanges per hour. V e r t i c a l
e l u t r i a t o r samples taken i n t h i s area du r ing th ree sample s e t s showed an
average dust l e v e l o f 255 . 3
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I In more convent ional g ins, m a t ? r i a l hand l i ng fans a r e u s u a l l y more I I
sca t te red throughout the p l a n t . The a i r supp l ied t o each fan i s taken i I from t h e surrounding workplace i n each u n i t process. A i rborne dus t
em i t ted a t the c lean ing stages migrates t o the o ther works i tes i n the g i n and causes an increase i n worker exposure.
A.1.5.4 P a r t i t i o n i n g
Th is g i n was cons t ruc ted w i t h a p r o v i s i o n fo r i n s t a l l i n g p a r t i t i o n s
i n the var ious process areas t o i s o l a t e sources o f dus t emission. The layou t o f the g i n stands and 1 s t and 2nd stages o f l i n t c lean ing a l lows
f o r i s o l a t i o n o f the t w o process areas. The duct work t h a t t r a n s p o r t s c o t t o n l i n t f i b e r from the g i n stands t o t h e l i n t c leaners was lengthened t o permi t the i n s t a l l a t i o n o f a p a r t i t i o n t h a t would c o n t a i n the l i n t
c lean ing opera t ion and i s o l a t e i t f rom the g i n stands and ba le press work
s i t e s . The average v e r t i c a l e l u t r i a t o r dust l e v e l recorded i n the l i n t c lean ing process area was 354 vg/m . 3
A.1.5.5 Expo,sure I s o l a t i o n
I n a d d i t i o n t o the i s o l a t i o n o f process areas, an enclosed o f f i c e
area has windows f o r observing the e n t i r e g inn ing opera t ion . Al though the g i n stand and ba le press c o n t r o l console i s no t i n s t a l l e d i n the o f f i c e
enclosure, workers can spend t i m e i n t h i s area and be i s o l a t e d f rom the
g inn ing operat ion. Th is reduces t h e i r t i m e weighted average exposure t o
c o t t o n dust dur ing the e i g h t hour work s h i f t .
A.1.5.6 Automatic Overf low Recyc l i ng
An automatic ove r f l ow " l i v e feed" recyc les excess seed c o t t o n sup- p l i e d t o the three g i n stands. Th is oven end suc t i on hopper c o l l e c t s the
over f low for pneumatic t ranspor t t o a separator above the conveyor d i s - t r i b u t o r . Th is system e l im ina tes manual r e c y c l i n g o f seed c o t t o n w i t h a
suc t i on p ipe and encloses t h i s operat ion. A fan d e l i v e r i n g 800 CFM o f exhaust a i r from t h i s process t ranspor t s seed c o t t o n from the " l i v e feed"
t o the conveyor d i s t r i b u t o r . As a r e s u l t of t h i s a i r be ing exhausted from
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I I I the a u t m a t i c seed overf low a i rbo rne dust and t r a s h e m i t t e d by the proces-
s ing equipment i s c o n t r o l l e d .
A . 1 . 5 . 7 L i n t Cleaner Process A i r
The layou t o f the l i n t c leaners and g i n stands make optimum use O f
pneumatic t r a n s p o r t t o reduce dus t emissions. The g i n stands and l i n t
c leaners are p o s i t i o n e d i n a d i r e c t l i n e (F igu re A.l-10) t o pe rm i t a
sequent ia l f l o w o f m a t e r i a l f rom the f r o n t t o the rear o f t h e g i n b u i l d -
ing. Motes and t r a s h removed by t h e l i n t c leaners are pneumat ica l l y
t ranspor ted t o the e x t e r i o r cyclones. Each o f the t h r e e 1 s t stage l i n t c leaners exhausts 12,900 CFM o f a i r . A t o t a l o f 38,700 CFM o f dus t laden
a i r i s exhausted from t h e 1s t stage l i n t c leaner condensers t o the ou ts ide
a i r .
A t the 2nd stage l i n t c leaners, c leaned c o t t o n f i b e r 1s t r anspor ted through a l i n t f l u e t o a b a t t e r y condenser. A t o t a l o f 33,000 CFM o f a i r
i s exhausted f rom the three 2nd stage l i n t c leaners t o t h e ou ts ide a i r .
A t o t a l o f 84.703 CFM o f a i r i s exhausted from t h e s i x l i n t c leaners. Make up a i r i s supp l ied t o each c leaner through f o u r 7' by 4" openings. A i r f l o w measurements taken a t the fat? of each o f t h e s i x openings showed capture v e l o c l t i e s ranging from 95-220 CFM. This p rov ided c o n t r o l over
dust and t r a s h m a t e r i a l be ing emi t ted from the equipment by induc ing a negat ive pressure i n s i d e the enclosure. There i s a d d i t i o n a l a i r supp l ied t o the l i n t c leaners through openings and gaps i n the enc losure o f each machi ne.
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._ ,.*. ..r.yr--.-- ,-- ..... -..---
A.1.5.8 Automatic Banding and Bale Removal (Process Equipment)
The ba le press a t t h i s c o t t o n g i n was complete ly au tana t i c w i t h a l l
funct ions, I n c l u d i n g compacting t h e c o t t o n l i n t , s t rapp ing the f u l l
bales, d o f f i n g , and t r a n s p o r t f o r t h e bales on a conveyor t o the ou ts ide . A l l f u n c t i o n s are c o n t r o l l e d by one worker a t a c e n t r a l console who a l so mon i to rs the operat ion. A convent iona l ba le press would need 3-4
employees f o r operat ion.
, I
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