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Weco
Butterfly Valve Home
Weco Butterfly Valves
Sizing Information
Non-Compressible Fluids
Use the following equations for sizing valves handling liquids
| Where: |
|
= |
Flow in gallons per minute (gpm) |
|
= |
Pressure Drop (psi) |
|
= |
Inlet pressure (psia) |
|
= |
Outlet Pressure (psia) |
|
= |
Specific Gravity of Liquid (Water = 1.0) |
|
= |
Valve Coefficient (Refer to Appropriate Table) |
The equations listed above are the basis for the WECO sizing
nomogram. The nomogram is a method of solving the equations above quickly
and simply when the service fluid is water.
| Example |
|
|
Given:
|
A 6" Weco Butterfly Valve is to be installed in a line handling
500 gpm of water. |
| Find: |
Maximum pressure drop across the valve when in the full open and
60° open positions |
| Solution: |
This problem may be solved using the nomogram or equation (C) |
| First Using the Nomogram: |
Enter nomogram on right side for a flow rate of 500 gpm. Draw
horizontal line until it intersects the 6" valve line. From this
point draw a vertical line until it intersects the 90° open line.
Project line horizontally to the left and read
.061 psi for 60° open. |
| Using Equation C |
Pressure Drop =
|
| Where: |
|
|
= |
500 gpm |
|
|
= |
|
|
|
= |
Specific Gravity of Liquid (Water = 1.0) |
|
|
= |
2020 @ 90° open (from tables) |
| GPM @ PSI @ Various Disc
Angles |
|
Valve Size, In
|
10° |
20° |
30° |
40° |
50° |
60° |
70° |
80° |
90° |
| 2 |
1.59 |
6.17 |
14.2 |
26.3 |
44.5 |
70.6 |
105 |
135 |
159 |
| 21/2 |
2.33 |
9.06 |
20.9 |
38.6 |
65.3 |
104 |
156 |
215 |
266 |
| 3 |
3.50 |
13.6 |
31.4 |
57.9 |
98.0 |
156 |
240 |
342 |
457 |
| 4 |
6.16 |
23.9 |
55.1 |
102 |
173 |
274 |
423 |
625 |
860 |
| 5 |
9.56 |
37.2 |
85.6 |
158 |
268 |
426 |
656 |
970 |
1,320 |
| 6 |
13.7 |
53.3 |
123 |
227 |
384 |
610 |
941 |
1,420 |
2,020 |
| 8 |
24.2 |
94.3 |
217 |
401 |
679 |
1,080 |
1,66 |
2,500 |
3,540 |
| 10 |
37.3 |
145 |
334 |
617 |
1,040 |
1,660 |
2,560 |
3,830 |
5,580 |
| 12 |
53.7 |
209 |
481 |
888 |
1,500 |
2,390 |
3,690 |
5,620 |
8,080 |
| 14 |
61 |
166 |
650 |
1,300 |
2,100 |
3,500 |
5,220 |
8,000 |
13,000 |
| 16 |
81 |
477 |
960 |
1,700 |
2,900 |
4,920 |
7,000 |
11,000 |
17,000 |
| 18 |
125 |
535 |
1,120 |
1,960 |
3,500 |
5,800 |
8,000 |
15,000 |
19,000 |
| 20 |
161 |
723 |
1,500 |
2,700 |
4,800 |
7,900 |
12,500 |
18,500 |
27,000 |
| 24 |
305 |
921 |
2,000 |
3,640 |
6,175 |
10,350 |
17,500 |
24,000 |
35,000 |
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