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Torque characteristics of a 122-centimeter butterfly valve with a hydro/pneumatic actuatorActuating torque data from field testing of a 122-centimeter (48 in.) butterfly valve with a hydro/pneumatic actuator is presented. The hydraulic cylinder functions as either a forward or a reverse brake. Its resistance torque increases when the valve speeds up and decreases when the valve slows down. A reduction of flow resistance in the hydraulic flow path from one end of the hydraulic cylinder to the other will effectively reduce the hydraulic resistance torque and hence increase the actuating torque. The sum of hydrodynamic and friction torques (combined resistance torque) of a butterfly valve is a function of valve opening time. An increase in the pneumatic actuating pressure will result in a decrease in both the combined resistance torque and the actuator opening torque; however, it does shorten the valve opening time. As the pneumatic pressure increases, the valve opening time for a given configuration approaches an asymptotical value.
Document ID
19820026468
Document Type
Reprint (Version printed in journal)
Authors
Lin, F. N. (NASA John F. Kennedy Space Center Cocoa Beach, FL, United States)
Moore, W. I. (NASA John F. Kennedy Space Center Cocoa Beach, FL, United States)
Lundy, F. E. (NASA Kennedy Space Center Cocoa Beach, FL, United States)
Date Acquired
August 10, 2013
Publication Date
September 1, 1981
Subject Category
MECHANICAL ENGINEERING
Distribution Limits
Public
Copyright
Other