Reference Manual

2−10
Table 2-4. Typical Rotary Shaft Valve Torque Factors V-Notch Ball Valve with Composition Seal
Fisher TCMt Plus Ball Seal
Valve Size,
NPS
Valve Shaft
Diameter,
Inches
A
B
C
Maximum T
D
,
LbfSIn.
Composition Bearings
(1)
60 Degrees 70 Degrees
1
1-1/2
2
3
4
6
8
1/2
5/8
5/8
3/4
3/4
1
1-1/4
0.07
0.12
0.19
0.10
0.10
1.80
1.80
50
100
175
280
380
500
750
0.38
1.10
1.30
0.15
1.10
1.10
3.80
0.48
1.10
2.40
3.80
18.0
36.0
60.0
515
1225
1225
2120
2120
4140
9820
10
12
14
16
16
20
1-1/4
1-1/2
1-3/4
2
2-1/8
2-1/2
1.80
4.00
42
60
60
97
1250
3000
2400
2800
2800
5200
3.80
11.0
75
105
105
190
125
143
413
578
578
1044
9820
12,000
23,525
23,525
55,762
55,762
1. PEEK/PTFE or metal/PTFE bearings.
Table 2-5. Typical High Performance Butterfly Torque Factors for Valve with Composition Seal
PEEK/PTFE Bearings with PTFE Seal
Valve Size Shaft Diameter
A B
C Maximum Allowable Torque
ANGLE OF OPENING S17400 H1075 S20910
NPS Inch
60_ (K) 90_ (q) lbfSin lbfSin
2 1/2 0.30 100 1.05 2.45 515 515
3 5/8 0.56 150 3.59 10.8 1087 1028
4 3/4 0.99 232 7.65 21.2 1640 1551
6 1 2.30 438 17.5 46.7 4140 4140
8 1-1/4 4.80 705 33.4 223 7988 7552
10 1-1/4 8.10 1056 82.2 358 9792 9258
12 1-1/2 12.5 1470 106 626 12000 12000
Table 2-6. Actuator Feature Comparison
Actuator Type Advantages Disadvantages
Spring-and-Diaphragm Lowest cost
Ability to throttle without positioner
Simplicity
Inherent fail-safe action
Low supply pressure requirement
Adjustable to varying conditions
Ease of maintenance
Limited output capability
Larger size and weight
Pneumatic Piston High thrust capability
Compact
Lightweight
Adaptable to high ambient temperatures
Fast stroking speed
Relatively high actuator stiffness
Higher cost
Fail-safe requires accessories or
addition of a spring
Positioner required for throttling
High supply pressure requirement
Electric Motor Compactness
Very high stiffness
High output capability
High cost
Lack of fail-safe action
Limited duty cycle
Slow stroking speed
Electro-Hydraulic High output capability
High actuator stiffness
Excellent throttling ability
Fast stroking speed
High cost
Complexity and maintenance difficulty
Large size and weight
Fail-safe action only with accessories