Valve Stem Coupling Assembly for Torque-Thrust Load Isolation
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Solution Overview
Problem
Gate valve stems often suffer damage due to combined thrust and torque loads, leading to the need for replacement and potential downtime, as existing systems do not effectively isolate these loads, causing damage when overtorque occurs.
Innovation Solution
A coupling assembly that separates thrust and torque loads using two stems, where one stem handles thrust and the other torque, with securing pins that shear in overtorque conditions to prevent damage and allow for easy replacement without taking the valve offline.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single stem is used to connect actuator to gate, then the structure is simple, but the stem bears both thrust load and torque load which can cause damage under overtorque conditions
Solution Approach 1:
The single stem is divided into two separate stems: a thrust stem that bears only axial thrust load from the gate, and a torque stem that bears only rotational torque load from the actuator. This segmentation eliminates the combined loading that causes damage, allowing each stem to be optimized for its specific load type and enabling easier replacement of damaged components.
2Manufacturing precision
If match drilled stems are used, then the stem connection is precise, but replacement requires taking the entire gate off-line
Solution Approach 1:
The stem connection is segmented into modular components (actuator, torque stem, coupling, thrust stem, gate) that can be independently replaced. The coupling assembly with standardized bores and keyways maintains precise alignment while allowing the torque stem to be replaced without removing the thrust stem or gate, significantly reducing valve downtime.
Solution Approach 2:
The coupling assembly is pre-configured with standardized features including bored holes and keyways that align the stems precisely before final assembly. This preliminary preparation ensures accurate alignment is achieved without requiring complex on-site matching operations.
3Device complexity
If a unitary stem bears both loads, then the design is straightforward, but damage requires complete stem replacement
Solution Approach 1:
The stem system is segmented into functional components (thrust stem and torque stem) connected through a coupling assembly. This allows the torque stem to be replaced independently when damaged, avoiding the need to replace the entire stem assembly and reducing manufacturing costs and inventory requirements.
4Strength
If securing pins are used to prevent twisting, then the connection is secure, but pin replacement requires major disassembly without access doors
Solution Approach 1:
The securing pins are extracted from hidden positions within the coupling and repositioned to be accessible through access doors provided in the actuator housing. This allows operators to inspect and replace securing pins without major disassembly of the valve, while the pins remain effective at preventing unwanted rotation during normal operation.
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
The solution effectively isolates torque and thrust loads, preventing stem damage and allowing for quick replacement of securing pins, ensuring continuous operation without major disassembly or expense, and maintaining valve integrity during overtorque conditions.
Implementation Method 1
the securing pin is engineered to shear and fail before any other part of the coupling assembly is damaged
Data Source
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AI summary
A coupler that separates a unitary valve stem into two separate but coupled sections to isolates the thrust load from the torque load.