Linear Actuator Rotary Output for Valve Position Instrumentation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Industrial linear valves, such as gate, knife, and plug valves, are inefficiently controlled due to the lack of compatible sensors and indicators, as most available instruments are designed for rotary inputs, leading to less accurate, reliable, and more complex or expensive process control systems.
Innovation Solution
A linear actuator with a rotary output mechanism, including a scissor linkage mechanism and swivel assembly, that converts axial piston movement into rotational displacement, allowing for direct engagement with conventional rotary instruments like Namur type positioners or indicators, providing visual and electrical signals indicative of valve position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a linear actuator is used to control linear valves, then the actuation is efficient and direct, but compatible sensors and indicators cannot be used directly because most instruments are designed for rotary inputs
Solution Approach 1:
A rotary output mechanism is introduced as an intermediary component between the linear actuator and conventional rotary instruments. This mechanism includes a scissor linkage with pivotable arms that convert linear piston movement into rotational motion of an output shaft, enabling compatibility with standard rotary sensors and indicators while maintaining efficient linear actuation of the valve
2Adaptability or versatility
If a rotary output mechanism is added to convert linear motion to rotational motion, then compatibility with rotary instruments is achieved, but the device complexity increases
Solution Approach 1:
The rotary output mechanism is segmented into distinct functional components: a scissor linkage system with multiple pivotable arms, a swivel assembly for rotational freedom, and an output shaft. This segmentation allows each component to perform its specific function independently while maintaining overall simplicity and ease of assembly
Solution Approach 2:
The mechanism is designed to operate within the compact volume of the actuator cylinder, with all moving parts contained within the existing cylindrical space. The scissor linkage arms pivot within the cylinder volume, and the output shaft extends through the cylinder wall, maintaining equipotential spatial utilization without requiring additional external space
3Adaptability or versatility
If the rotary output element is positioned on top of the cylinder for instrument mounting, then instrument compatibility is achieved, but accessibility and visual inspection become difficult and potentially dangerous in installations behind guard rails or safety screens
Solution Approach 1:
The output shaft is oriented horizontally rather than vertically, extending through the side wall of the cylinder instead of the top. This dimensional reorientation allows instruments to be mounted on the side of the actuator, making them accessible from the front or side while the actuator remains positioned behind safety barriers. The rotary motion is maintained while changing the spatial dimension of output delivery
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enables accurate, reliable, and cost-effective control of linear valves by using a rotary output mechanism that integrates with existing rotary instruments, improving accessibility and safety in industrial settings, particularly in large-scale installations where access is limited.
Implementation Method 1
a scissor linkage mechanism, comprising a plurality of elongate linkage elements pivotably interconnected in a criss-cross configuration within the cylinder
Implementation Method 2
axial movement of the piston effects a corresponding rotational displacement of the rotary output element
Implementation Method 3
the swivel assembly enabling relative rotational displacement between the scissor linkage mechanism and the piston around the cylinder axis
Data Source
Figure 1~3
Figure 4~5
Figure 6~7
AI summary
This invention provides a linear actuator with a cylinder defining a cylinder axis. A piston is movable within the cylinder along the cylinder axis, and a piston rod extends axially from the piston for connection to a mechanism whereby in use, movement of the piston actuates the mechanism. A rotary output mechanism includes a rotary output element extending generally transversely from the cylinder and supported for rotation about an output axis generally normal to the cylinder axis. The rotary output mechanism is responsive to movement of the piston, and the rotary output element is adapted for operative engagement with an instrument mounted to the cylinder such that axial movement of the piston effects a corresponding rotational displacement of the rotary output element, whereby in use the instrument provides an output signal indicative of the position of the piston within the cylinder.