Document RjpO1Y6Q5GJdKnBe7y0jjbaxB

y. *! L- * ^ 1078 CHAPTER 47 1 Drying, by W. R. Marshall, Jr. and S. J. Friedman, Perry's Chemical Engineers' Handbook, McGraw-Hill Book Co., Inc., New York, 3rd Edition, 1950. Indicated material supplied by W. R. Marshall, Jr. and S. J. Friedman, authors of the Section on Drying in the Third Edition of the Chemical Engineers' Handbook. Permis sion to use this material has been kindly granted to The Guide by the Editor, John H. Perry, and by McGraw-Hill Book Company, publishers of the Chemical Engineers' Handbook. * The Drying of Foods, by W. R. Marshall, Jr. (Heating, Piping and Air Condition- ing, September to December, 1942, and November and December, 1943). * Drying Materials in Trays, by C. B. Shepherd, C. Hadlock and R. C. Brewer (Industrial and Engineering Chemistry, April, 1938). . 4 Drying of Solids by Through-Circulation, by W. R. Marshall, Jr. and 0. A. Hougen (Transactions, American Institute of Chemical Engineers, 1942). 8 Heat, Mass and Momentum Transfer in the Flow of Gases through Granular Solids, by B W. Gamson, G. Thodos and O. A. Hougen (Transactions, American Institute of Chemical Engineers, 1943). 6 Mass Transfer in the Flow of Gases through Granular Solids Extended to Low Modified Reynolds Numbers, by C. R. Wilke and O. A. Hougen (Transactions, Ameri can Institute of Chemical Engineers, 1945). 1 Limitations of Diffusion Equations in Drying, by O. A. Hougen, H. J. McCauley and W. R. Marshall {Transactions, American Institute of Chemical Engineers, 1940). 8 What the Air Conditioning Engineer Should Know About Drying (Heating and Ventilating, December, 1942). * Spray Drying, by Ben B. Fogler and Robert V. Kleinschmidt (Industrial and Engineering Chemistry, December, 1938). 10 An Introduction to Convection Drying and Drying Calculations, by V. P. Victor (Healing and Ventilating, Vol. 41, Dec. 1944, p. 67). BIBLIOGRAPHY The Temperature of Evaporation, by W. H. Carrier (A.S.H.V.E. Transactions, Vol. 24,1918, p. 25). TThheerrmmooddyynnaammiicc P1 roperties of Moist Air, by John A. Goff and S. Gr&tch (A.S.H.V.E. Transactions, V oolL. f5l1l, 1945. p. 125). Factors Influencing the P^erf'orman--c--e--o-tf-nR-o*.t--ary iD>rtyyeerrasf, bbyy CC.. FF.. PPrruuttttoonn aanndd C. O. Miller (.Transactions. American Institute ofChemical Engineers, Part I, FFeebbrruuaarryy,, 11994422;; PPaarrtt 22,, AAuugguusstt,, 11942). Drying of Solids by Through Circulation, by W. R. Marshall and O. A. lilougef n (Transactions, American InstFitauctetorosf TChheamt iIcnaflluEenngcineeDerrsy,e1r94P2e).rformance, by A. Weisselberg (Chemical and Metallurgical Engineering, AugTuyspt,ic1a9l32D).ryer Calculations, by O. A. Hougen (Chemical and Metallurgical Engineering, January and MarScyhm, 1p9o4s0iu).m on Drying, Articles by W. K. Lewis, W. H. Carrier, A. E. Stacey. Jr,, R. S. Fleming, R. G Mete, G. B. Ridley, C. O. Lovett, D. J. Van Marie (Industrial and Engineering Chemistry, May, 1921, pp. 427S-4t6u0d)i.es in Rotary Drying. I nod II, by S. J. Friedman and W. R. Marshall, Jr. (Chemical kngineenng Progress, 1949). SPyrimncpipolseiusmofoDn rDyirnygingLu(mInbdeurstarinadl aHndumEnidgiitnyeeDriinaggrCahme,mbisytryH, .19D38. )T. iemann (Forest Service Bulletin, KM, 191T2)h. e Drying of Solids, by T. K. Sherwood (Bulletin, Massachusetts Institute of Technology, Nos. 237, 24/, andR2a5d8)i'a. nt Energy Drying with Heat Lamps, by T. P. Brown (Metal Industry, Vol. 37. Dec. 1939, p. 607). Drying by Sublimation, by E. W. Flosdorf (rood Industry, Vol. 17, Jon. 1945, p. 607).Evaporative Drying System, by F. H. Slade (Food Manufacturing, Vol, 18, March, 1943, p. 70). High Frequency Methods in Gluing and Drying Wood, by I. R. Berkness (Wood Products, Vol. 45, 1W0, p. 1D2e)v.elopment of the Unit Operations of Chemical Engineering; Drying, by T. K. Sherwood (Chemi.ca,l A MTehtealSluprgraicyalDErynegirn--eIetrsinPg,oVssoibl.il4it2ie, sp.in21I4n)d. ustry, by D. W. Biocheno (Food Manufacturing, Vol, 19, June. 1944M, epc. h1a9n5i)s.m and Rate of Drying by Near-infra-red Radiation, by L. E. Stout, K. J. Caplan and. _. rw BaiSrdom(TeraEnsnagcintioenesrinAgmePrriocabnlemInsstitouftetohef ChNeemwicaVl Eegnegtianbeelers,DVeohl.yd4r1a, t1io94n5, pIn.d2u8s3)t.ry, by W. B. Van Arad, *.1 (A.S.H.V.E. Transactions, Vol. 49, 1943, p. 49). Electronic Dehydration of Foods, by V. W. Sherman (Electronics, Vol. 17, 1944, p. 94). Air Conditioning and Engineering, American Blower Co., 1935. Drying in Industrial Plants, J. 0. Roes Company. Elements of Chemical Engineering, by Badger and McCabe (McGraw-Hill Co., 1931). Fan Engineering, Buffalo Forge Co. Die Trockentechnik, by M. Hirscb (Julius Springer, Berlin, 1932). Drying (Kent's Mechanical Engineers Handbook). Drying, by W. H. Carrier (Mark's MesJianical Engineers Handbook). Kiln Drying of Lumber, by A. Koehler and R. Tbelen, New York, 1926. Kiln Drying of Lumber, by H. D. Tiemann (Lippincott, 1920). CHAPTER 48 TRANSPORTATION AIR CONDITIONING Railway Passenger Car Air Conditioning; Streetcar and Trolley Coach Heating and Ventilating; Passenger Bus Air Conditioning; Automobile Air Conditioning; Aircraft Air Conditioning; Ship Air Conditioning, Heating and Venti lating, Refrigeration Systems, Air Condition Space Treatment, Systems and Controls THE principles of air conditioning applying to stores, restaurants, hos pitals, theaters, and homes are applicable to . railway passenger cars, passenger buses, automobiles, streetcars, trolley coaches, airplanes and ships. However, equipment used for mobile applications differs from that used for stationary purposes in that it must meet additional requirements. Equipment must be compact, accessible for quick inspection and servicing, light-weight and unaffected by vibration and impact. Freedom from vi bration which could be transmitted to supporting vehicle and thus to pas sengers, is essential. RAILWAY PASSENGER CAR AIR CONDITIONING The railway passenger car represents a very difficult air conditioning problem. Space is strictly limited so that ail equipment and ducts must be reduced to minimum size. Electric power supply and water supply also are limited. All equipment must withstand severe vibration and shock, and must be very reliable since servicing points are frequently far apart. During the heating season it is necessary to heat conventional cars with steam from the locomotive at pressures that may vary from 250 psig to only 5 or 10 psig on the last car in long trains. Passengers in window seats must sit only a few inches from cold outside walls and windows, and must also be very close to standing radiation installed along sides of cars. Sud den changes in load may be caused by changes in sun, wind, or train move ment. Even in coldest weather, outside doors must be opened frequently. During the cooling season, the problem is further complicated by a high concentrated internal load due to the passengers. Also, air distribution problems are increased by low ceilings and short air throws. Heating The heating of passenger cars is accomplished by using a split system consisting of an overhead air circulating system with heating and cooling coils, and standing radiation (floor heat) along car sides. The floor heaters, which usually consist of finned tubing, may be made more efficient by using covers designed to increase gravity air circulation, and to direct the warm air from finned heating surface along cold outside walls and car windows. In some new cars, wall convector panels are used and extend the mu length of the car, with air intakes along the floor and outlets at win dow sill height and at window head height in dead-light panels. The heated Panel protects passengers from cold outside walls, and the chimney effect of Panel duct increases air flow and improves heating surface efficiency. Steam may be used directly in finned tubing, or steam may be used to nea^ a liquid (usually a mixture of water and diethylene glycol) which is 1079