Document DGDvGRXR8Y0LzmKj4ORq3YEJo

802 CHAPTER 34 1956 Guide Operation and Maintenance of Air Filters, by W. G. Frank (Heating, Piping and Air Conditioning, May, 1931, p. 378). : Size and Characteristics of Air-Borne Impurities, by W. G.'Frank (Herding, Piping and Air Conditioning, January, 1932, p. 35). Fundamental Principles in the Design of Dry Air Filters, by Otto Wechsberg (A S H V.E. Journal Section, Healing, Piping and Air Conditioning, April, 1933, p. 217). The Economic Factors in Converting Recirculated Air for Ventilation, by H. E. Ziel and Henry Sleik (A.S.H.V.E. Journal Section, Heating, Piping and Air Condi tioning, July, 1943, p. 367). A.S H.V.E. Research Report No. 1094--Air Filter Performance as Affected by Kind of Dust, Rate of Dust Feed, and Air Velocity Through Filter, by F. B. Rowley and R. C. Jordan (A.S.H.V.E. Transactions, Vol. 44,1938, p. 415). A.S.H.V.E. Research Report No. 1122--Air Filter Performance as Affected by Low Rate of Dust Feed, Various Types of Carbon, and Dust Particle Size and Den sity bv F. B. Rowley and R. C. Jordan (A.S.H.V.E. Transactions, Vol. 45, 1939, p. 339) A.S.H.V.E. Research Report No. 1145--The Effect of Lint on Air Filter Perform ance, by F. B. Rowley and R. C. Jordan (A.S.H.V.E. Transactions, Vol. 46, 1940, p. 25). . ... ; ' A.S.H.V.E. Research Report No. 1169--Comparison of the Weight, Particle Count and Discoloration Methods of Testing Air Filters, by F. B. Rowley and R. C. Jordan (A.S H.V.E. Transactions, Vol. 47, 1941, p. 29). A.S.H.V.E. Research Report No. 1187--Economical Air Velocities for Mechan ical Air Filtration, byF. B. Rowley and R. C. Jordan (A.S.H.V.E. Transactions, Vol. 47, 1941, p. 391). A.S.H.V.E. Research Report No. 1218--Overloading of Viscous Air Filters Dur' ing Accelerated Tests, by F. B. Rowley and R. C. Jordan (A.S.H.V.E. Transactions, Vol. 48, 1942, p. 437). A New Electrostatic Precipitator, by G. W. Penney (Electrical Engineering, Jan uary, 1937,p. 159). Electrostatic Precipitation for Aircraft, by Howard E. Corbitt and Norman J. Clark (Aero Digest, December, 1940, p. 132). Pointers on Selecting Equipment for Industrial Gas Cleaning, by C. E. Miller (Chemical and Metallurgical Engineering, 45, March, 1938, p. 132-5). Electrical Precipitation, by W. A. Schmidt and E. Anderson (Electrical Engineer ing, 57, August, 1938, p. 332-338). Electrical Precipitation, by A. W. Simon and L. C. Kron (Electrical Engineering, 51, February; 1932, p. 93-5). Some Factors and Principles Involved in the Separation and Collection of Dust, Mist and Fume from Gases, by Evald Anderson (Transactions, American Institute of Chemical Engineers, 16, 1924, Pt. 1, p. 69-86). Electrical Precipitation of Solids from Smelter Gases, by Ross B. Rathbun (Trans actions, American Institute of Electrical Engineers, 41, 1922, p. 815). Characteristics of Unit Dust Collectors, by Arthur C. Stern, Jack BaliiL E. Perina, Robert Crowley, Benjamin Feiner and Arthur A. Urbano (A.S.H.V.E. Transactions, Vol. 52, 1946, p. 237). Operation, Application and Effectiveness of Dust Collection Equipment, by John M. Kane (Heating and Ventilating, Reference Section, August 1952). Air Pollution Abatement Manual--Chapter 9, by C. A. Lapple (Manufacturing Chemists Association). Handbook on Air Cleaning, by Sheldon K. Friedlander, Leslie Silverman, iJimip Drinker and Melvin W. First. (U. S. Atomic Energy Commission, Washington, D. C.). Performance of Wet Cell Washers for Various Aerosols, by M. W. First, R. Mos* chella, L. Silverman, and E. Berly (Industrial and Engineering Chemistry Vol. 1951, p. 1363). Chemical Engineers Handbook, by John H. Perry. (McGraw-Hill Book Co., 3rd Edition 1950). American Industrial Hygiene. Association Quarterly, March 1950. Design Factors in Catalytic Fume Elimination, by R. J. Ruff (Healing and Venti lating, September 1953, p. 84). CHAPTER 35 SPRAY APPARATUS Air Washers, Humidification with Air Washers, Dehumidification and Cooling with Air Washers, Well and Water Main "Temperatures, Apparatus for Direct Humidification, Unit Humidifiers, Water-Cooling Towers, Water Use and Conservation, Rivera and Lakes, Spray Cooling Ponds, Atmos pheric and Mechanical Draft Cooling Towers, Mechanics of At mospheric Water-Cooling, Design Conditions, Water-Cooling Tower Design, Selection of Water-Cooling Towers, Operation and Maintenance AIR humidification is effected by the vaporization of water, and always requires heat from some source.. This heat may be added to the water prior to the time vaporization occurs, or it may be secured by a transformation of sensible heat of the air being humidified to latent heat as the vapor-is-added to the air. The thermodynamics of the process are discussed in Chapter 3. The removal of moisture from air may, or may not, involve the removal of heat from the air-vapor mixture. With spray equipment, dehumidification of air always necessitates the removal of heat. AIR WASHERS An air washer consists essentially of a chamber or casing in which is provided a spray nozzle system, a tank at the bottom of the chamber for collecting the spray water as it falls, and an eliminator section at the leaving end of the chamber for removal of drops of entrained moisture from the delivered air. Air is drawn through the casing of the washer, where it comes into intimate contact with the spray water. A heat trans fer takes place between the air and water, resulting in either humidifica tion or dehumidification of the air, depending upon the method of operation and the relative temperatures of air and spray water. To prevent backlash of spray ahead of the washer chamber, and to aid in more uniform air distribution, inlet diffusion plates or eliminator baffles, where necessary, are provided in the air entrance end of the air washer. Inlet diffusion plates are used when the air flow and water spray are in the same direction; eliminator baffles of special design are used where one or more of the water sprays opposes the air flow. At the out let end of the washer suitable flooded eliminator plates are used. These plates, for the removal of entrained moisture, usually cause four to six changes in direction of the air flow. Figs. 1 and 2 show the essential construction features of conventional air washers. Intimate contact between the air and the water is secured U) by breaking the water into fine drops; (2) by passing the air over sur faces continuously wetted by water; or (3) by a combination of the two. The wetted surfaces in an air washer may be of fiber glass, metal or scrubber plate construction: Scrubber plate types of washers are generally used to wash reclaimable products from the air, and are composed of several baffle type plates located across the air stream. Water is supplied at the top of the washer to spray over these plates. In the case of the fiber glass or metal surfaces, the water spray is usually rather coarse and at 803