by B. Purushothama
Contents
Preface ix
1 Need for maintaining humidity 1
1.1 Introduction 1
1.2 Relation of humidity to working in the textile mills 2
1.3 Dust control 5
1.4 Control of air pollution 8
1.5 Air changes 8
1.6 Humidity and the health 9
1.7 Protection of electronics and equipments 10
2 A glance at the developments 12
2.1 General 12
2.2 Unit humidifiers 14
2.3 Central station-type plant 14
2.4 Supplementary humidification 18
2.5 All-air system 18
2.6 Energy management 18
3 Different types of humidification 22
3.1 Steam humidification 22
3.2 Evaporative pan 29
3.3 Water spray humidifiers 36
4 Air handling units in textile industry 41
4.1 Introduction 41
4.2 Supplying air to air washer plants 45
4.3 Air filter construction and cleaning system 49
4.4 Type of fans used 57
4.5 Gravity louver damper 62
4.6 Eliminators 62
4.7 Water spray 65
4.8 Water supply 71
4.9 Supply air distribution 73
4.10 Roto-spray units 76
4.11 Chilling plants or cooling towers 76
4.12 Temperature and humidity monitoring 85
5 Humidification requirements in manmadefibre plants 87
5.1 Introduction 87
5.2 Quench box 87
5.3 Take-up area 89
5.4 Draw twist area 91
5.5 Textile area 91
5.6 Other areas 92
6 Humidification requirements in nonwoven plants 95
6.1 Processes in nonwoven plant 95
6.2 Air distribution needs in nonwoven industry 96
6.3 Material air-conditioning and spot air-conditioning 98
6.4 Cleaning of the air 98
6.5 Recycling and disposal of wastes 99
6.6 Compact Filter Unit (CFU) 100
7 Concept of total air control 101
7.1 Introduction 101
7.2 Different individual solutions 102
7.3 Cleaning and disposal of air 105
7.4 Controls 108
7.5 After-sales service: trouble-free operation 109
8 Localised humidification control 110
8.1 Need for localised humidification control 110
8.2 Use of heating lamps 111
8.3 Subsystem humidification 112
8.4 AirBell air outlet 114
8.5 Exhausting air 115
8.6 Machine air-conditioning 117
8.7 Super soft terry towels weaving 118
8.8 Yarn-conditioning plants 118
8.9 Static elimination 120
9 Maintenance of humidity 121
9.1 Understanding the calculations 121
9.2 Operation and problems associated with air washer systems 130
9.3 Efficient use of humidification plants 136
9.4 Keeping AHUs clean 139
9.5 Monitoring humidity 149
9.6 Problems of not getting required conditions 153
9.7 Basic humidity control preparation 155
9.8 Guidelines to select supply outlets and return grilles 156
9.9 Guidelines to size the duct runs 157
9.10 Power consumption 157
9.11 Ionisation of air using chemicals 160
10 Auxiliary units to make humidification units effective 162
10.1 Building design to have effective control of humidity 162
11 Air-conditioning units 174
11.1 History of air conditioning 174
11.2 Application of air conditioning 177
11.3 Different types of air conditioners 179
11.4 Design for air conditioning system 185
11.5 Central air conditioning 192
11.6 Health implications 193
12 Air pollution control in textile industry 194
12.1 Introduction 194
12.2 Source of air pollution 195
12.3 Air pollution control 196
12.4 Use of UV disinfestations 203
12.5 An integrated approach for the textile industry 204
13 Dehumidification 206
13.1 Introduction 206
13.2 Reducing the humidity 206
13.3 Types of dehumidification 207
14 Designing heating, ventilating and airconditioning (HVAC) 212
14.1 What is HVAC? 212
14.2 Fundamental of energy and resource-efficient HVAC design 213
15 Definitions of terms used in humidification engineering 227
Appendix 1 Some of the commercial humidification plants 253
Appendix 2 Cooling and heating systems 308
Appendix 3 Fogging fans and Jets 317
Appendix 4 Spray nozzles and mist eliminators 346
Appendix 5 Fans and blowers 356
Appendix 6 Dampers and diffusers 373
Appendix 7 Sensors and data loggers 387
Appendix 8 Dehumidifiers 418
Appendix 9 Fume and dust control, air ventilation 424
hose and ducts
Appendix 10 Filters and dust collectors 431
References 443
Preface
The importance of maintaining and managing humidity and temperature in a textile mill is not a new concept, but understanding the requirements, the equipment capabilities and utilizing them to get the best results is a challenge the technicians face all the time. Now the systems have changed from manually operated to fully automatic; however, unless one knows how to monitor, he shall still have the problem. Some guidelines are needed for the shop floor technicians relating to maintenance of humidity and monitoring the air.
The idea of writing a book on Managing of Humidity came from my friend Ananth Harnahalli. I hesitated first, as I was only a Textile Technologist and not a Humidification Engineer. Ananth reminded me that I had faced lot of problems due to improper maintenance of humidity while working on the shop floor and had struggled a lot to get required conditions. The problems faced were always unique as the systems were getting changed, materials were getting changed and also the working conditions. Ananth told that the purpose of this book should be to guide the shop floor technicians and engineers in maintaining required conditions and to act in advance. They need the basic concepts and the choice available in the market to update their humidification plants; hence this book.
An attempt is made to collect and provide information starting from the basic concepts, developments, varying needs of the industry, the problems associated with maintenance of plants to get the required conditions, designing of plant capacity, modification or designing of building to get the best results, various issues of health and hygiene, the pollution control issues, various models available in the market, etc. However, it should be noted that it is practically impossible to explain all the equipments and give details of all manufacturers. Hence, efforts are made to explain at least one unit in each type.
I am thankful for all the information providers, without which this book would not have come out. Also I am thankful to all my friends who encouraged me to write this book, and the family members for their complete cooperation. My special thanks are to Ravindra Saxena and Sumit Aggarwal for the initiations taken to publish this book so that it could reach masses.
B. Purushothama