Pneumatic drive: What is the relationship with valve torque?
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What is the relationship between the torque of the pneumatic actuator and the valve torque?
With more pneumatic actuation devices, the torque valves are angular-motion valves such as ball valves, butterfly valves, and plug valves.
Gear-and-rack actuators exhibit a linear torque-output characteristic, while fork-type actuators have a U-shaped torque-output characteristic. The torque of a valve is generally highest at the open or closed position, and lower during the process of opening or closing it. The torque curve of ball valves makes the fork-type actuator particularly suitable for use in such applications.
The valve torque is determined by multiplying the torque required for specific operating conditions by a certain safety factor; this is the torque needed for the pneumatic actuator