Page 121 - APPLIED PROCESS DESIGN FOR CHEMICAL AND PETROCHEMICAL PLANTS, Volume 1, 3rd Edition

Fluid Flow 107

'Gauge DIAMETER OF ORIFICE
Pressure
before Orifice 04 1"
in Pounds -~
per sq. in. 1 Discharge in Cubic feet of free air per minute
1. . . . . . . . . . . . .028 .112 .450 1.80 7.18 16.2 28.7 45.0 64.7 88.1 115
2. . . . . . . . . . . . .040 ,158 .633 2.53 10.1 22.8 40.5 63.3 91.2 124 162
3. . . . . . . . . . . . .048 ,194 .775 3.10 12.4 27.8 49.5 77.5 111 152 198
4. . . . . . . . . . . . .056 .223 .892 3.56 14.3 32.1 57.0 89.2 128 175 228
5. . . . . . . . . . . (. 1 .062 .248 .993 3.97 15.9 35.7 63.5 99.3 143 195 254
6 .068 .272 1.09 4.34 17.4 39.1 69.5 109 156 213 278
7 .073 .293 1.17 4.68 18.7 42.2 75.0 117 168 230 300
9 .083 .331 1.32 5.30 21.2 47.7 84.7 132 191 260 339
i .I23 .491 1.96 7.86 31.4 70.7 126 196 283 385 503
12 .095 ,379 1.52 6.07 24.3 54.6 97.0 152 2 18 297 388
15 .IO5 ,420 1.68 6.72 26.9 60.5 108 168 242 329 430
80.9
8.98
.I40
648
496
365
.I58 .562 2.25 10.1 35.9 91.1 144 225 323 440 575
40.5
.633
2.53
162
253
.I76 .703 2.81 11.3 45.0 101 180 281 405 551 720
40 .194 .774 3.10 12.4 49 .B 112 198 310 446 607 793
___
45 211 .&I5 3.38 13.5 54.1 122 216 338 487 662 865
50 .229 .916 3.66 14.7 58.6 132 235 366 528 718 938
60 .264 1.06 4.23 16.9 67.6 152 271 423 609 828 1082
70 .300 1.20 4.79 19.2 76.7 173 307 479 690 939 1227
80 .335 1.34 5.36 21.4 85.7 193 343 536 77 I 1050 1371
--
.370 1.48 5.92 23.7 94.8 213 379 592 853 1161 1516
.406 1.62 6.49 26.0 104 234 415 649 934 1272 1661
.441 1.76 7.05 28.2 113 254 452 705 1016 1383 1806
.476 1.91 7.62 30.5 122 274 488 762 1097 1494 1951
,494 1.98 7.90 31.6 126 284 506 790 11% 1549 2023
Table is based on 100% coefficient of flow. For well rounded entrance multiply values by 0.97. For sharp edged orifices a multiplier of
0.65 may be used for approximate results,.
Values for pressures from 1 to 15 Ibs. gauge calculated by standard adiabatic formula.
Values for pressures above 15 Ib. gauge calculated by approximate formula proposed by S. A. Moss.
aCPl Where:
W, = discharge in lbs. per sec.
a = area of orifice in sq. in.
C = Coefficient of flow
PI = Upstream total pressure in Ibs. per sq. in. absolute
TI = Upstream temperature in OF. abs.
Value9 used in calculating above table were; C = 1.0, PI = gauge pressure + 14.7 Ibs./sq. in. Ti = 530" F. abs.
Weights (W) were converted to volumes using density factor of 0.07494 Ibs./cu. ft. This is correct for dry air at 14.7 Ibs. per SQ. in.
absolute pressure and 70" F.
Formula cannot be used where PI is less than two times the barometric pressure.
*By permission "Compressed Air Data," F. W. O'Neil, Editor, Compressed Air Magazine, 5th Edition, New York, 1939 [49].
Example 2-9: Steam Flow Using

Table 2-124 is coinvenient for most air problems, not- Determine the pressure loss in 138 feet of $-inch
ing that both free air (60°F and 14.7 psia) and com- Schedule 40 steel pipe, flowing $6,000 pounds per hour
pressed air at 100 pig and 60°F are indicated. The cor- of 150 psig steam (saturated).
rections for other temperatures and pressures are also Use Figure 2-32, w = 86,000/60 = 1432 Pbs/min
indicated. Figure 2-37 is useful for quick checking. How-
ever, its values are slightly higher (about 10 percent) than Reading from top at 150 psig, no superheat, down ver-
the rational values of Table 2-11, above about 1000 cfm of tically to intersect the horizontal steam flow of 1432
free air. Use for estimating only. lbs/min, follow diagonal line to the horizontal pipe size