. Transactions - American Society of Heating, Refrigerating and Air-Conditioning Engineers. weight of steam in lb. per hr. V T= velocity in ft. per = equivalent length of pipe in ft. ^ = acceleration of gravity ( ft. per sec. per sec). d = diameter of pipe in ft. r = factor of resistance experimentally determined. 1 Report of Research Committee, National District Heating Association, Proceedings, 1920,p. 67. 2 Effect of Fittings on Flow of Fluids through Pipe Line, by D. E. Foster, MechanicalEngineering, November, 1920, p. 616. * Mechanics of Heating and Ventilating, by Konrad Meier
. Transactions - American Society of Heating, Refrigerating and Air-Conditioning Engineers. weight of steam in lb. per hr. V T= velocity in ft. per = equivalent length of pipe in ft. ^ = acceleration of gravity ( ft. per sec. per sec). d = diameter of pipe in ft. r = factor of resistance experimentally determined. 1 Report of Research Committee, National District Heating Association, Proceedings, 1920,p. 67. 2 Effect of Fittings on Flow of Fluids through Pipe Line, by D. E. Foster, MechanicalEngineering, November, 1920, p. 616. * Mechanics of Heating and Ventilating, by Konrad Meier, McGraw-Hill, 1912. Fractional Distribution in Steam-Heating Systems, Adler and Donnelly 303 To find the equivalent length of pipe, i. e., a length of pipe such that thedrop of pressure in the pipe is equal to that in the fitting, equate (4) and(5) ; hence IVv^^ L^ fFrz;! = (6) 288^rfi-i« 288^ from which by reduction and transposition Le := rd ^?^^ (7) Table 1 gives values for various fittings expressed in equivalent lengthof pipe in ft. as computed from Equation FIG. 2. CROSS-SECTIONAL VIEW OF FRACTIONAL DISTRIBUTION VALVE PRESSURE DROP THROUGH ORIFICES The general law of flow through orifices as given in numerous textson the subject is: Q^cAv (8) where Q = quantity delivered in cu. ft. per sec. c = an experimentally determined constant here assumed at and which remains constant for a wide range of = area in sq. = velocity in ft. per sec. From mechanics: ^=^i^2 gh (9) where h = hydrostatic head in ft. But since the head is proportional to the pressure by the relation P=zhD (10) where P = pressure in lb. per sq. ft.; £>== density in lb. per cu. ft., 304 Transactions of Am. Soc. of Engineers substituting the value of h in (10), in (!i) there results v= i2g — (11) I ^ Insert (11) for the value of v in (8), hence 0 =cA \2 n V DTo convert the quantity Q into weight W in lb. per min. it must bemultiplied by the density D tim
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