Most technological devices use butterfly valves to check the flow rate and speed, through piping. Their main advantages are their low cost, their mechanical suitability for fast operation, and their small pressure drops when they are fully open. The fluid dynamic torque about the axis of large valves has to be considered as the actuator could be overstrained. This torque is generally defined using a nondimensional coefficient KT, in which the static pressure drop created by the valve is used for normalization. When the valve is closed downstream of an elbow, the valve pressure drop is not well defined. Thus, the classic normalization method gives many ambiguities. To avoid the use of the pressure drop, we define another torque coefficient CT in which the dynamic pressure of the flow is the normalization factor instead of the pressure drop. Advantages and drawbacks of each normalization method are described in the following.

1.
Bryer, D. W., and Walshe, D. E., 1969, “Devices for Reducing the Fluid-Dynamic Torque on Butterfly-Valve Discs,” National Physical Laboratory Aerodynamics Division, Report 1298.
2.
Eom
K.
,
1988
, “
Performance of Butterfly-Valves as a Flow Controller
,”
ASME JOURNAL OF FLUIDS ENGINEERING
, Vol.
110
, pp.
16
19
.
3.
Morris, M. J., Dutton, J. C., and Addy, A. L., 1987, “Peak Torque Characteristics of Butterfly-Valves,” Proceedings of the Forum on Industrial Applications of Fluids Mechanics, ASME FED-Vol. 54, pp. 63–66.
4.
Morris
M. J.
, and
Dutton
J. C.
,
1989
, “
Compressible Flow Field Characteristics of Butterfly-Valves
,”
ASME JOURNAL OF FLUIDS ENGINEERING
, Vol.
111
, pp.
399
407
.
5.
Morris
M. J.
, and
Dutton
J. C.
,
1991
, “
An Experimental Investigation of Butterfly-Valve Performance Downstream of an Elbow
,”
JOURNAL OF FLUIDS ENGINEERING
, Vol.
113
, pp.
81
85
.
6.
Morris
M. J.
, and
Dutton
J. C.
,
1989
, “
Aerodynamic Torque Characteristics of Butterfly-Valves in Compressible Flow
,”
ASME JOURNAL OF FLUIDS ENGINEERING
, Vol.
111
, pp.
392
399
.
7.
Morris, M. J., 1987, “An Investigation of Compressible Flow Through Butterfly-Valves,” Ph.D. thesis, Department of Mechanical and Industrial Engineering, University of Illinois at Urbana-Champaign.
8.
Silvester
R. S.
,
1982
, “
Torque Induce by Butterfly-Valve Carrying a Compressible Flow
,”
IMechE, Proc. Instn. Mech. Engrs.
, Vol.
196
, pp.
229
237
.
This content is only available via PDF.
You do not currently have access to this content.