Document eK6rr4kgEMp7r8JzyBookLOm

HEATING VENTILATING AIR CONDITIONING CUIDE.1943 'a. rate of metabolism as possible. Ideal conditions range between 55 to , 57 :F and'in no case should the temperature go below 49 F,- as the starches then become fixed and are indigestible. The curing of lemons is an entirely different problem. Bananas are cured .for a quick market, while lemons are held for a future market. The process, therefore, varies in the temperature used. Temperatures from 54 to 59 F have been found to be best suited for this process. A high relative humidity of 88 to 90 per cent is necessary to hold shrinkage to a minimum and, at the same time, develop the rind so it will be sufficiently -tough to permit handling. Tobacco from the field, to the finished cigar, cigarette, plug or pipe tobacco, offers another interesting example of what may be done by industrial air conditioning in the control of color, texture and flavor. In the processing of tobacco, the first three classifications of air con ditioning are involved, and only through close atmospheric control can the best quality of the leaf be developed. Control. Rate of Crystallization The rate of cooling of a saturated solution determines the size of the crys tals formed. Both dry- and wet-bulb temperatures are of importance, as the one controls the rate of cooling, while the other, through evaporation, changes the density of the solution. . In the coating pans for pills,' gum and nuts, a heavy sugar solution is added to the tumbling mass. As the water evaporates, each separate piece is covered with crystals of sugar. A smooth, opaque coating is only accomplished by blowing into the kettle the proper amount of air at the right dry- and wet-bulb temperatures. . Elimination of Static Electricity . The presence of static electricity is very detrimental to the satisfactory and economical processing of many light materials, such as textile fibers, paper, etc. It is.also extremely dangerous where explosive, atmospheres or- materials are present. Fortunately, this hazard is easily eliminated by increasing the relative humidity. In attempting to eliminate static electricity, it.must be borne in mind that for successful elimination the air that actually comes in contact with the material in the machine must.be at a relative-humidity of 50 per cent or more. As some machines consume a great deal of power which is converted directly into heat, the. temperature in the machine may be considerably higher than the temperature adjacent to the machine where the relative humidity is normally measured. In such cases, the relative humidity in the machine will be appreciably lower than that elsewhere in the room, and it may be necessary to maintain a room relative humidity of 65 per cent, or even more, before the desired results can be obtained. CALCULATIONS , The methods for determining the proper heating and cooling loads for the various industrial processes are similar to those outlined in Chapters 6 and.7.' Because of the large number of motors and heat producing units 728 CHAPTER 39. INDUSTRIAL AIR CONDITIONING usually prevalent in an industrial application, it is particularly important that operating allowances for the latent and sensible heat loads be definitely ascertained and used in the calculations to determine the total design load. REFERENCES Food Air Conditioning for Sausage Manufacturing Plants, by M. G. Harbula (A.S.H.V.E. Transactions, Vol. 28, 1922, p. 343); Air Conditioning in the Bakery, by W. L. Fleisher (A.S.H.V.E. Journal Section, Heating, Piping and Air Conditioning, February, 1931, p. 158). Proper Air Conditions for the Manufacturing of Confections, by A. E. Stacey, Jr. (A.S.H.V.E. Journal Section, Heating, Piping and Air Conditioning, October, 1937, p. 640). Air Conditioning and Refrigerating Large Bakeries, by W. L. Fleisher (Heating, Piping and Air Conditioning, December, 1929, p. 621; January, 1930, p. 24). Pre-Cooling Fruits and Vegetables with Circulating Air, by C. E. Baker (Heating, Piping and Air Conditioning, January, 1932, p. 42). Air Conditioning Maintains Quality of Fruits and Vegetables, by C. E. Baker{Healing, Piping and Air Conditioning, August, 1935, p. 369). Air Condition the Bakery Throughout, by W. W. Reece (Heating, Piping and Air Conditioning, August, 1936, p. 149). Banana Ripening Manual, Circular No. 14, Equipment Department, Fruit Dispatch Co., New York, N. Y. The Commercial Storage of Fruits, Vegetables and Florists' Stocks, by D. H. Rose, R. C. Wright and T. M. Whiteman (Ui 5. Department of Agriculture, Circular No. 278); Temperature Studies of Some Tomato Pathogens, by Alice A. Nightingale and G. W. Ramsey (U. S. Department of Agriculture Technical Bulletin No. 520, August, 1936). PRINTING Hygro-Xylometric Control of Air Conditioning, by H. H. Tunis (A.S.H.V.E. Journal. Section, Heating,Piping and Air Conditioning, November, 1937, p. 637). Air Conditioning of Press Rooms, by I. C. Baker (Heating, Piping and Air Con ditioning, July, 1931, p. 553). Newspaper Plant Air Conditioned for Efficient Production, by J. A. Osborn (Heating, Piping and Air Conditioning, January, 1932, p. 40). Air Conditioning Frees Rotogravure Plant from Weather Hazards, by H. E. Jacobsen (Heating, Piping and Air Conditioning, September,-1935, p. 423). Bureau of Standards Studies Determine Press Room Conditioning-Requirements, by C. G. Weber (Heating, Piping and Air Conditioning, March, 1936, p. 137).. Silica Gel. Air Conditioning System Serves Rotogravure Printing Plant, by H. E. Ryerson (Heating, Piping and Air Conditioning, August, 1937, p. 497). Moisture Control by Liquid Absorption Offers a Useful Air Conditioning Tool, by F. M. Johnson (Healing, Piping and Air Conditioning, December, 1938, p. 782). Meeting the Air Requirements in a Bindery and Printing Plant, by N. W. Downes (Heating and Ventilating, February, 1921, p. 25). Heating and Ventilating the Bureau of Engraving and Printing (Heating and Venti lating, February, 1923, p. 55). Humidity in the Pressroom (Heating and Ventilating, May, 1932, p. 35). Dehumidifying with Gas in a Printing Plant (Heating and Ventilating, May, 1935, p. 31). Air Conditioning in the Paper Industry (Healing and Ventilating, October, 1935, P-23). Air Conditioning the Newspaper Plant, by R. T. Williams (Heating and Ventilating, September, 1937,.p. 63). 729