Dynamic torque factors (imperial), Resilient seated butterfly valves – torques – Bray 31U User Manual
Page 12
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 : 12
Series 20/21 and 30/31/3A (Dynamic Torque Factor - lb-in./psi)
Angle of Opening
10°
20°
30°
40°
50°
60°
70°
75°
80°
90°
Valve
Size
inches
2
0.113
0.126
0.225
0.453
0.726
1.251
2.139
3.068
3.052
0.000
2.5
0.216
0.240
0.430
0.865
1.386
2.388
4.085
5.858
5.827
0.000
3
0.367
0.408
0.732
1.473
2.359
4.065
6.952
9.970
9.918
0.000
4
0.855
0.949
1.702
3.425
5.486
9.454
16.168
23.187
23.065
0.000
5
1.650
1.833
3.287
6.613
10.593
18.253
31.217
44.769
44.533
0.000
6
2.494
2.771
4.969
9.997
16.014
27.594
47.192
67.680
67.323
0.000
8
6.603
6.736
12.077
24.298
38.925
67.073
114.707
164.506
163.64
0.000
10
11.990
13.322
23.885
48.056
76.985
132.653
226.862
325.353
323.640
0.000
12
20.892
23.214
41.619
83.735
134.142
231.141
395.295
566.910
563.925
0.000
14
30.039
33.377
59.841
120.396
192.873
332.342
568.366
815.119
810.828
0.000
16
45.652
50.724
90.942
182.970’
293.115
505.070
863.764
1,238.762
1,232.240
0.000
18
65.909
73.232
131.295
264.159
423.178
729.184
1,247.040
1,788.435
1,779.020
0.000
20
91.415
101.573
182.105
366.387
586.945
1,011.373
1,729.637
2,480.549
2,467.498
0.000
Example: 4” Valve; 60° Open with a 10 PSI pressure drop: [Td = (9.454)(10) = 94.54 lb-in]
Series 32/33, 35/36 (Dynamic Torque Factor - lb-in./psi)
Angle of Opening
10°
20°
30°
40°
50°
60°
70°
75°
80°
90°
Valve
Size
inches
24
158.358
175.953
315.459
634.688
1,016.758
1,751.990
2,996.230
4,297.026
4,274.403
0.000
30
315.318
350.353
628.133
1,263.773
2,024.539
3,488.513
5,966.008
8,556.117
8,511.072
0.000
36
551.884
613.205
1,099.388
2,211.917
3,543.447
6,105.766
10,441.998
14,975.332
14,896.492
0.000
Larger Size Valves - Consult Factory
Example: 24” Valve; 60° Open with a 10 PSI pressure drop: [Td = (1,751.990)(10) = 17,519.90 lb-in]
Dynamic Torque Factors (Imperial)
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 PSI ∆P. To determine
dynamic torque (lb-in) 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.