Читать книгу Mechanics of the Household - E. S. Keene - Страница 22
PROPORTIONING THE SIZE OF MAINS
ОглавлениеFor any size system of steam or water heating the following rule will be found entirely satisfactory for mains 100 feet long; for each 100 feet additional use a size larger ratio.
Rule.—
r = (3.1416/d)R = a/r × 100.
r represents ratio of main in inches for each 100 feet of surface; d, diameter of pipe; R, quantity of radiation carried by size of pipe; a, area of pipe in inches.
From this the following table has been constructed:
Diameter of pipe | Area of pipe | Ratio to each 100 feet of surface | Quantity of radiation, steam or water, on a given size pipe |
1½ | 1.767 | 2.10 | 84 |
2 | 3.141 | 1.57 | 200 |
2½ | 4.908 | 1.25 | 400 |
3 | 7.069 | 1.04 | 700 |
3½ | 9.621 | 0.90 | 1,062 |
4 | 12.566 | 0.78 | 1,590 |
4½ | 15.904 | 0.70 | 2,272 |
5 | 19.625 | 0.63 | 3,120 |
6 | 28.274 | 0.52 | 5,440 |
7 | 38.484 | 0.45 | 8,550 |
8 | 50.265 | 0.40 | 12,556 |
9 | 63.617 | 0.35 | 18,100 |
10 | 78.540 | 0.30 | 25,300 |