Owner manual
Resilient Seated Butterfly Valves – Torques
All information herein is proprietary and condential 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.