Steam, Its Generation and Use

by Babcock & Wilcox Company

If the pipe length is the same as assumed in [the table] but the loss is different, the quantity of steam passing per minute will be,

Q 1 = Q l½ ( 47 )

For any assumed pipe length and loss of pressure, the weight will be,

Q 1 = Q ( 240 dl ––––––––––– L ) ½ ( 48 )

[TABLE 67] FLOW OF STEAM THROUGH PIPES LENGTH OF PIPE 1000 FEET Discharge in Pounds per Minute corresponding to Drop in Pressure on Right for Pipe Diameters in Inches in Top Line Drop in Pressure in Pounds per Square Inch corresponding to Discharge on Left: Densities and corresponding Absolute Pressures per Square Inch in First Two Lines Diameter [82] —Discharge Density—Pressure—Drop 12 10 8 6 4 3 2½ 2 1½ 1 .208 .230 .284 .328 .401 .443 .506 .548 Inches Inches Inches Inches Inches Inches Inches Inches Inches Inch 90 100 125 150 180 200 230 250 2328 1443 799 371 123. 55.9 28.8 18.1 6.81 2.52 18.10 16.4 13.3 11.1 9.39 8.50 7.44 6.87 2165 1341 742 344 114.6 51.9 27.6 16.8 6.52 2.34 15.60 14.1 11.4 9.60 8.09 7.33 6.41 5.92 1996 1237 685 318 106.0 47.9 26.4 15.5 6.24 2.16 13.3 12.0 9.74 8.18 6.90 6.24 5.47 5.05 1830 1134 628 292 97.0 43.9 25.2 14.2 5.95 1.98 11.1 10.0 8.13 6.83 5.76 5.21 4.56 4.21 1663 1031 571 265 88.2 39.9 24.0 12.9 5.67 1.80 9.25 8.36 6.78 5.69 4.80 4.34 3.80 3.51 1580 979 542 252 83.8 37.9 22.8 12.3 5.29 1.71 8.33 7.53 6.10 5.13 4.32 3.91 3.42 3.16 1497 928 514 239 79.4 35.9 21.6 11.6 5.00 1.62 7.48 6.76 5.48 4.60 3.88 3.51 3.07 2.84 1414 876 485 226 75.0 33.9 20.4 10.9 4.72 1.53 6.67 6.03 4.88 4.10 3.46 3.13 2.74 2.53 1331 825 457 212 70.6 31.9 19.2 10.3 4.43 1.44 5.91 5.35 4.33 3.64 3.07 2.78 2.43 2.24 1248 873 428 199 66.2 23.9 18.0 9.68 4.15 1.35 5.19 4.69 3.80 3.19 2.69 2.44 2.13 1.97 1164 722 400 186 61.7 27.9 16.8 9.03 3.86 1.26 4.52 4.09 3.31 2.78 2.34 2.12 1.86 1.72 1081 670 371 172 57.3 25.9 15.6 8.38 3.68 1.17 3.90 3.53 2.86 2.40 2.02 1.83 1.60 1.48 998 619 343 159 52.9 23.9 14.4 7.74 3.40 1.08 3.32 3.00 2.43 2.04 1.72 1.56 1.36 1.26 915 567 314 146 48.5 21.9 13.2 7.10 3.11 0.99 2.79 2.52 2.04 1.72 1.45 1.31 1.15 1.06 832 516 286 132 44.1 20.0 12.0 6.45 2.83 0.90 2.31 2.09 1.69 1.42 1.20 1.08 .949 .877 748 464 257 119 39.7 18.0 10.8 5.81 2.55 0.81 1.87 1.69 1.37 1.15 .97 .878 .769 .710 665 412 228 106 35.3 16.0 9.6 5.16 2.26 0.72 1.47 1.33 1.08 .905 .762 .690 .604 .558 582 361 200 92.8 30.9 14.0 8.4 4.52 1.98 0.63 1.13 1.02 .828 .695 .586 .531 .456 .429

To get the pressure drop for lengths other than 1000 feet, multiply by lengths in feet ÷ 1000.

[Pg 320]

Example: Find the weight of steam at 100 pounds initial gauge pressure, which will pass through a 6-inch pipe 720 feet long with a pressure drop of 4 pounds. Under the conditions assumed in [the table] , 293.1 pounds would flow per minute; hence, Q = 293.1, and

Q 1 = 293.1 ( 240 × 6 × 4 ––––––––––––––––––– 720 × 12 ) ½ = 239.9 pounds

[Table 67] may be frequently found to be of service in problems involving the flow of steam. [This table] was calculated by Mr. E. C. Sickles for a pipe 1000 feet long from formula ( [45] ), except that from the use of a value of the constant K = .0026 instead of .0027, the constant in the formula becomes 87.45 instead of 87.