Dust control in traffic signals using water sprayers.


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A technique which can be implemented in traffic signals for controlling dust.

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Dust control in traffic signals using water sprayers.

  1. 1. Dust control in trAFFic siGnAls usinG wAter sprAyers. By, JINAL JOLLY, 20074614, B.E AIE, CEG, Anna University.
  2. 2. r  Environmental Problems in cities  Effects  Control using sprayers  Principle  Operation  Factors affecting efficiency  Maintenance  Advantages and disadvantages  Conclusion CONTENTS
  3. 3. 1. Industrial air pollution. 2. Intensive automobile exhaust. 3. Improper waste management. CURRENT ENVIRONMENTAL PROBLEMS IN CITIES?
  4. 4. r  Short term effects: • Irritation to eye, nose and throat. • Respiratory problem such as bronchitis, Pneumonia, asthma. • Head ache, nausea, etc…  Long term effects: • Chronic respiratory diseases, • Lung cancer, • Damage to heart, brain and nerves. EFFECTS OF DUST POLLUTION
  5. 5. r  Traffic junctions  Roads  Factories  Bus terminus  Open grounds, etc… WHERE THE DUST IS FOUND IN CITIES ?
  7. 7. r AS AN ENGINEER, HOW CAN WE CONTROL THESE ROADS? WATER SPRAYERS IN TRAFFIC SIGNALS: “ Spraying of water subsides dust. “  Water sprayers can be attached in the traffic signal posts, in which it can spray water when the signal is turned red.
  8. 8. r  Dust consists of solid particles larger than 1 µm in diameter.  Dust particles smaller than 10 µm are the most dangerous since they are respirable.  These are the dusts which we commonly find in roads  How dust is generated in roads? • Dust carried from vehicles from other places • Automobile emissions • Through wind DUST
  9. 9. r “ Very fine water drops collide with dust particles in the air, to form agglomerates of dust and water which are too heavy to remain suspended in air. “ Hence the agglomerates settle down which ultimately means that the dusts settle down. PRINCIPLE OF SUBSIDENCE
  10. 10. r  The sprayer nozzles should be fitted to the posts in the traffic signal  High pressure pipeline water supply is connected to the nozzle.  A time dependent sensor should be fixed along with that such that the spraying starts whenever the signal turns red, and it ends just before the signal turns green.  This ensures that the water sprayed will not fall on vehicles. OPERATION
  11. 11. r THREE TYPES OF WATER EJECTORS 1. Water sprinklers 2. Water sprayers 3.Water atomizers
  12. 12. r 1) Drop size:  Drops that are too large will not collide with the finest and most hazardous dust particles.  Drops that are too small evaporate quickly and release the captured dust.  Nozzles that produce a misty rain and wet fog consisting of drops in the 10 to 100 µm range are most effective.  Collision is most likely to occur when the size of drops are 2 to 4 times bigger than dust particles FACTORS AFFECTING EFFICIENCY OF THE SYSTEM
  13. 13. r
  14. 14. r DROP SIZE DIAMETER (µM) TYPE OF DROP TIME FOR PARTICLE TO SETTLE DOWN FOR 10FT ( sec) 2,000 to 5,000 Heavy rain 0.9 to 0.85 1,000 to 2,000 Intense rain 1.1 to 0.9 500 to 1,000 Moderate rain 1.6 to 1.1 50 to 500 Light rain 5 to 1.6 10 to 50 Misty rain 16 to 5 5 to 10 Wet fog 26 to 16 1 to 5 Dry fog 100 to 26 Type of droplets, size and time taken to settle
  15. 15. r 2) Spray angle: A spray angle between 265°and 275° offers the best coverage without compromising the creation of agglomerates. 3)Drop velocity: The drop velocity should be very high to get a good efficiency. If it is less, then the water spread area will reduce. 4)Water pressure: The water pressure at the nozzle should be very high inorder to attain a very high drop velocity.
  16. 16. r  The nozzles should be checked and cleaned regularly so that the holes are not blocked by dust particles.  The angle and tightness of the sprayer should be checked for exact wide spread area.  Timing of the sprayer should be checked to coincide with the signal MAINTENANCE
  17. 17. r
  18. 18. r  Effective dust control method.  Spraying is automatic.  Respirable dusts are made settle  Maintains a nourishing weather.  Not necessary to use very pure water  Very less labour requirement.  Economical, once the system is installed. ADVANTAGES
  19. 19. r  Proper maintenance needed.  Stable water source is required.  Not suitable for countries which have very less temperature.  Installation charges may be high. DISADVANTAGES
  20. 20. r  Hand sprayers are used in agriculture for fertilizer spraying.  Dry fog sprayers are used in cement factories for dust suppression APPLICATION OF WATER SPRAYERS IN OTHER INDUSTRIES
  21. 21. r • For controlling dust pollution in Indian cities, very minimum efforts have been taken from the Government side. • If we implement these water sprayers, it will be a very effective as well as economical way to solve the pollution crisis. • So lets widen our scope beyond agricultural field towards environmental conservation to create a dust free city. CONCLUSI ON
  22. 22. r • `www.osha.gov/SLTC/silicacrystalline/dust/chapter • www.thomasnet.com/.../nozzles • www.technologytransfertactics.com/.../water-spray-system REFERENCE
  23. 23. r THANK YOU