INDUSTRIAL AND ENGINEERING CHEMISTRY
June, 1945
s91
ACKNOWLEDGMENT
TABLE 11. VALVE FLOWCOEFFICI~NT~ CALCULATED FROM EQUATION 3, USINGDATAOBTAINEDBY CORPAND RUBLZ(8) AND THE CRANE COMPANY (4) FOR Loss OF HEADTHROUGH GLOBEVALVES~8 COMPARED TO COEFFICIENTS OBTAINEDIN THIS STUDY Fully Open Re for Valve Siae of: 1/1
Corp and Ruble (1922) Crane Co. Kroll and Fairbanks (1944) a
b e
-
-
in.
0.088@ 0.097s 0.100
*/a in. 0.208
1 in. 0.861
o:lbb
o:iiio
Used valves at Reynolds numbers leas than 20,000. Calaulated from k 10.0 in II kVV2o. One wed valve.
Thanks are due to B. E. Hunt for the drawings and to F. M. Lundgren who took the pictures of the valves and apparatus used.
A*
- -
NOMENCLATURE
cross-sectional a m of discharge opening, sq. ft. D = diameter of pipe, ft. = acceleration due to avity, 32.17 (ft./sec.)/sec. = loss of head, feet of &id k: = coefficient, dimensionless K = flow coefficient, dimensionless K. KA2 valve flow coefficient, s ft. PI, p z = pressures a t upstream and 3ownstream pressure taps, respectively, lb./sq. ft. aPd = = Uerential pressure, lb./sq. in. 144. V = velocity of water, ft./sec. w = weight rate of discharge, Ib./sec. p 5 density, lb./cu. ft.
%
’ a
2. The ordinary commercial globe valves of the type and make used in this study may be used as flowmeters without calibration by use of the valve flow coefficient, K,, from which the rate of flow may be calculated, where a maximum error of 5% is permissible. 3. Greater precision with larger size valves is indicated by the fact that the maximum deviation for the l’/r-inch v@lveSwas only 3%. 4. The principal advantages of a valve meter are: (a) It may be used aa an adjustable orifice for widely varying conditions of flow; (b) the valve is already in the pipe line and hence there is no increased resistance to flow; (c) little initial cost is incurred by converting a valve into a flowmeter; and ( d ) the upkeep is small.
LITERATURE CITED
(1) Am. Boo. Meoh. Engrs., “Flow Measurement”, p. 45, par. 121 (1940). (2) Am, Boo. Meoh. Engrs., “Fluid Meters Report”, 4th ed., p. 48, par. 155 (1937). (3) Corp and Ruble, Univ. Wisconsin Eng. Expt.Sta., Bull. 9, No. 1 (1922). (4) Crane Co.,Catdog 41,p. 630 (1941). (5) Oeaa, Louis, Instrumatation, 1, No. 2,26 (1944). (6) Kroll. A. E..C h . & Met. Em.. 51, No. 7. 114 (1944). (7j Perry, J. H., Chemical Enginiers Handbook, ind ed., p. 848. New York,McGraw-HiU Book Go., 1941.
Interchain Order and Orientation in Cellulose Esters-Correction A
B
C
D
An unfortunate error occurred in connection with Figure 6 of this article by W. 0. Baker in the March, 1945, issue of INDUSTRIAL AND ENQINP)ERINQ C ~ M I S T R Y ,page 252. Each x-ray diagram of this figure rn printed in the original article should be considered as rotated by 90’ so that the fiber axis, shown horiaontally, becomes vertical. Poor reproduction, due to the quality of paper now available, destroyed the diagrams; Table I11 (page 253) gives the actual features. Figure 5 is reproduced here, placed and captioned correctly.
Figure 5. X-Ray Diagrams of Starch Triestere A . Tapiwm atamh triawtate, unoriented B Comstuoh triloetate drawn u n i U I d y C: T8plocr .taroh tribu&ate, unoriented D . Potato at& tripmapionate, oriented
