Rotary valve actuators having partial stroke damping apparatus

Abstract

Rotary valve actuators having partial stroke damping apparatus are described herein. An example rotary valve actuator described herein includes a housing containing a first piston and a second piston opposite the first piston, where the pistons move in opposite directions to rotate a shaft of the rotary valve actuator. A damper is operatively coupled to at least one of the first piston or the second piston to slow the movement of the piston for only a portion of a stroke of the rotary valve actuator.

Description

technical field [0001] The present invention relates generally to actuators and, more particularly, to rotary valve actuators with part-stroke damping devices. Background technique [0002] Process control equipment or systems often use rotary valves, such as butterfly valves, to control the flow of process fluids. In general, rotary valves typically include a fluid flow control component disposed within a fluid flow path between an inlet and an outlet of the rotary valve. The fluid flow control member is rotatably coupled by a shaft relative to the valve body of the rotary valve. Typically, a portion of a shaft extending from a rotary valve is operably coupled to an actuator (eg, a pneumatic actuator, a hydraulic actuator, etc.) that moves in a first direction and a second direction opposite the first direction. Two-way rotary valve shaft. [0003] In operation, a control unit (eg, a positioner) may supply a control fluid (eg, air) to the actuator to position the fluid f...

AI Technical Summary

Problems solved by technology

This configuration greatly reduces the efficiency of the actuator and greatly reduces or limits the overall closing speed and output torque provided by the actuator

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