FLOW OF STEAM THROUGH PIPES
LENGTH OF PIPE 1000 FEET
+--------------------------------------------------++----------------------------------------+
| Discharge in Pounds per Minute corresponding to || Drop in Pressure in |
| Drop in Pressure on Right for Pipe Diameters || Pounds per Square Inch corresponding |
| in Inches in Top Line || 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|
| In | In | In | In | In | In | In | In | In | In || 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.
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
_ _
| 240×6×4 |
Q_{1} = 293.1 | ------- |^{½} = 239.9 pounds
|_ 720×12_|
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.
In using this table, the pressures and densities to be considered, as
given at the top of the right-hand portion, are the mean of the initial
and final pressures and densities. Its use is as follows: Assume an
allowable drop of pressure through a given length of pipe. From the
value as found in the right-hand column under the column of mean
pressure, as determined by the initial and final pressures, pass to the
left-hand portion of the table along the same line until the quantity is
found corresponding to the flow required. The size of the pipe at the
head of this column is that which will carry the required amount of
steam with the assumed pressure drop.
The table may be used conversely to determine the pressure drop through
a pipe of a given diameter delivering a specified amount of steam by
passing from the known figure in the left to the column on the right
headed by the pressure which is the mean of the initial and final
pressures corresponding to the drop found and the actual initial
pressure present.
For a given flow of steam and diameter of pipe, the drop in pressure is
proportional to the length and if discharge quantities for other lengths
of pipe than 1000 feet are required, they may be found by proportion.