Flowseal® High Performance Butterfly Valves

 

Valve Flow Coefficients


Cv (Coefficient of Volume) is the number of U.S. gallons per minute of water required to pass through a valve with a pressure drop of 1 psi. The chart below records this Cv factor for the Flowseal valve classes and sizes at ten degree increments between open and closed. The values shown are for the valve installed in the seat upstream (“SUS”) position.

 

 

Degree Open
% Full Cv
10°
1.5%
20°
6%
30°
14%
40°
25.2%
50°
38%
60°
55%
70°
75%
80°
97%
90°
100%
2" 150 1.5 6 14 25 39 56 76 99 102
300 1.4 6 13 24 36 52 71 95 100
600 1.4 5 13 23 35 51 70 90 93
2-½" 150 2.2 9 21 37 56 80 110 142 146
300 2.1 8 19 34 52 75 102 136 143
600 - - - - - - - - -
3" 150 3.4 14 32 57 87 125 171 221 228
300 3.2 13 30 53 81 117 159 212 223
600 3.1 12 29 52 79 114 156 202 208
3-½" 150 5.3 21 49 88 132 192 261 338 349
300 4.8 19 45 80 121 176 240 320 336
4" 150 6.8 27 63 114 171 248 338 437 451
300 6.2 25 58 104 157 228 310 414 435
600 5.8 23 54 98 147 213 290 375 387
5" 150 10.8 43 100 180 271 392 535 692 714
300 9.8 40 92 165 248 361 491 655 688
6" 150 16.5 66 154 278 419 607 827 1070 1103
300 14.9 60 139 250 377 546 744 992 1041
600 14.7 59 137 247 372 538 734 950 979
8" 150 30.9 124 289 520 784 1135 1584 2002 2064
300 27.3 109 255 459 692 1001 1365 1820 1911
600 26.8 107 250 451 679 983 1341 1734 1788
10" 150 52.8 211 492 886 1336 1934 2638 3411 3517
300 45.6 183 426 767 1156 1673 2282 3042 3194
600 41.2 165 384 692 1044 1511 2060 2665 2747
12" 150 72.6 290 677 1219 1838 2660 3628 4690 4837
300 63.3 253 590 1063 1602 2319 3163 4217 4428
600 58.4 233 545 981 1479 2140 2918 3774 3891
14" 150 90 392 914 1646 2481 3592 4898 6530 6857
300 81 326 760 1368 2063 2986 4072 5430 5702
600 73 292 682 1228 1838 2680 3655 4727 4873
16" 150 132 531 1230 2229 3361 4865 6634 8845 9287
300 109 435 1015 1827 2755 3988 5438 7850 8243
600 96 385 899 1619 2423 3533 4818 6231 6424
18" 150 171 684 1596 3873 4332 6270 8550 11270 11400
300 139 555 1295 2331 3515 5088 6938 9250 9712
20" 150 207 828 1932 3478 5244 7590 10350 13800 14420
300 158 630 1470 2646 3990 5775 7875 10150 10658
24" 150 315 1260 2940 5292 7890 11550 15750 21000 22050
300 242 966 2254 4057 6118 8855 12075 16100 16205
30" 150 491 1965 4585 8253 12445 18012 24563 32750 34388
300 404 1614 3766 6779 10222 14795 20175 26900 28245
36" 150 707 2830 6602 11884 17920 25938 35370 45745 47160
42" 150 963 3851 8987 16176 24392 35304 48143 62264 64190
48" 150 1258 5030 11738 21128 31859 46111 62881 81324 83840

 

Cf FACTORS

The critical flow factor, Cf, expresses the valve pressure recovery ratio. It is equivalent to FL in ISA nomenclature.

 

 

Disc degree opening 15° 20° 25° 30° 35° 40° 45° 50°
Seat upstream 0.95 0.91 0.84 0.81 0.78 0.8 0.77 0.74
Seat downstream 0.94 0.89 0.84 0.82 0.8 0.77 0.75 0.72

Disc degree opening 55° 60° 65° 70° 75° 80° 85° 90°
Seat upstream 0.74 0.73 0.7 0.66 0.63 0.6 0.57 0.53
Seat downstream 0.69 0.66 0.63 0.6 0.58 0.55 0.54 0.53

Copyright © 2017 Crane Co. All Rights Reserved.