Dynamic torque factors (metric), Resilient seated butterfly valves – torques – Bray 31U User Manual
Page 13
Resilient Seated Butterfly Valves – Torques
All information herein is proprietary and confidential and may not be copied or reproduced without the expressed written consent of BRAY INTERNATIONAL, Inc.
The technical data herein is for general information only. Product suitability should be based solely upon customer’s detailed knowledge and experience with their application.
Torque : 13
To Use the Torque Chart, note the following:
1.
Dynamic Torque values include all bearing friction and
stem-seal friction torques.
2.
Dynamic Torque values are per 1 Bar ∆P. To determine
dynamic torque (N-m) at a desired angle of opening, multiply
the pressure drop ∆P at this angle by the appropriate dynamic
torque factor in the charts below.
3.
Bray recommends sizing control valves between 20° and
70°, with 60° the preferred angle.
4.
Dynamic Torque will tend to close all Bray valves whose
disc are symmetrical to the stem.
Series 20/21 and 30/31(Dynamic Torque Factor - N-m/bar)
Angle of Opening
10°
20°
30°
40°
50°
60°
70°
75°
80°
90°
Valve
Size
mm
50
0.001
0.001
0.002
0.004
0.006
0.010
0.017
0.024
0.024
0.000
65
0.002
0.002
0.003
0.007
0.011
0.019
0.032
0.046
0.045
0.000
80
0.003
0.003
0.006
0.011
0.018
0.032
0.054
0.078
0.077
0.000
100
0.007
0.007
0.013
0.027
0.043
0.074
0.126
0.181
0.180
0.000
125
0.013
0.014
0.026
0.052
0.083
0.142
0.243
0.349
0.347
0.000
150
0.019
0.022
0.039
0.078
0.125
0.215
0.368
0.528
0.525
0.000
200
0.052
0.053
0.094
0.190
0.304
0.523
0.895
1.283
1.276
0.000
250
0.094
0.104
0.186
0.375
0.600
1.035
1.770
2.538
2.524
0.000
300
0.163
0.181
0.325
0.653
1.046
1.803
3.083
4.422
4.399
0.000
350
0.234
0.260
0.467
0.939
1.504
2.592
4.433
6.358
6.324
0.000
400
0.356
0.396
0.709
1.427
2.286
3.940
6.737
9.662
9.611
0.000
450
0.514
0.571
1.024
2.060
3.301
5.688
9.727
13.950
13.876
0.000
500
0.713
0.792
1.420
2.858
4.578
7.889
13.491
19.340
19.246
0.000
Example: 100 mm Valve; 60° Open with a 10 Bar pressure drop: [Td = (.074)(10) = .74 N-m]
Series 32/33, 35/36 (Dynamic Torque Factor - N-m/bar)
Angle of Opening
10°
20°
30°
40°
50°
60°
70°
75°
80°
90°
Valve
Size
mm
600
1.235
1.372
2.461
4.951
7.931
13.666
23.371
33.517
33.340
0.000
750
2.459
2.733
4.899
9.857
15.791
27.210
46.535
66.738
66.386
0.000
900
4.305
4.783
8.575
17.253
27.639
47.625
81.448
116.808
116.193
0.000
Larger Size Valves - Consult Factory
Example: 600 mm Valve; 60° Open with a 10 Bar pressure drop: [Td = (13.666)(10) = 136.66 N-m]
Dynamic Torque Factors (Metric)