Valve Stem Lifter Assembly for Long-Stroke Multi-Size Valve Actuation
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Solution Overview
Problem
Traditional rotary valve actuators require multiple, expensive machined parts and have limited stroke length, making them inefficient and costly for operating multiple sizes of valves, and prone to damage from continuous cycling.
Innovation Solution
A valve stem lifter with a longer stroke length (approximately 3 inches per 270° rotation) is designed to reduce the number of parts and machining costs, allowing for universal operation of multiple valve sizes with reduced torque transmission and backlash.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional rotary valve actuators are used with multiple machined parts, then valve operation is achieved, but manufacturing cost and inventory requirements increase
Solution Approach 1:
The patent combines multiple separate components (rotary shaft, pull shaft, and valve stem lifter) into an integrated assembly where the rotary shaft directly drives the pull shaft through a unified mechanical linkage, eliminating the need for separate machined parts and reducing inventory requirements
Solution Approach 2:
The valve stem lifter is designed as a universal mechanism that can operate multiple sizes of valves through a single actuator system, with the ability to accommodate different valve diameters and stroke length requirements without requiring valve-specific custom parts
2Length of moving object
If traditional rotary valve actuators are used, then valve operation is achieved, but stroke length is limited
Solution Approach 1:
The patent extends the stroke length by utilizing a longer rotary shaft rotation range (beyond the traditional 90-degree limit), allowing the pull shaft to achieve greater linear displacement through extended rotational movement, thereby providing approximately 3 inches of stroke per 270° rotation
3Productivity
If continuous cycling of pull shaft is performed without full extension, then valve operation speed increases, but valve damage occurs
Solution Approach 1:
The valve stem lifter incorporates a full-extension mechanism that ensures the pull shaft completely extends to its maximum stroke length before reversing direction, preventing premature reversal that would cause valve damage, while still maintaining efficient cycling through optimized mechanical leverage
Data Source
AI summary
A valve stem lifter assembly which operates to alternatively open and close a valve, includes a rotatably mounted rotary shaft having a top end axially aligned with a riser with a rigidly connected pull shaft and an opposite end axially aligned with an operator for selectively producing rotational movement of the rotary shaft and corresponding axial movement of the riser and pull shaft. The rotary shaft is rotatably connected to the riser by radius set screws positioned horizontally in the grooves of the rotary shaft. A plurality of guide shaft rods passing through the riser interconnects the riser to the valve stem lifter assembly to prevent axial separation of the riser and rotary shaft, and rotation of the riser, while permitting free relative rotation of the rotary shaft and axial movement of the riser and pull shaft.