Quick-Change Valve Trim Assembly for Stuck Cage Removal
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Solution Overview
Problem
The existing pressure regulating valves, especially unbalanced ones, face issues with valve seat damage due to high inlet pressures, leading to costly and time-consuming repair or replacement processes, and the removal of trim assemblies is often cumbersome due to sticking cages, requiring additional bores for extraction.
Innovation Solution
A pressure regulator trim assembly design that includes a mechanical stop within the cage, allowing the valve plug and cage to be removed as a unit, reducing repair and replacement time and eliminating the need for additional bores by ensuring the valve plug and cage are extracted together.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the standard removal process is used (removing bonnet, then valve plug, then cage), then each component can be accessed individually, but the process is time-consuming and the cage often becomes stuck requiring additional lifting holes
Solution Approach 1:
The patent combines the valve plug and cage into a single removable unit by providing a lifting aperture in the cage that receives a lifting tool attached to the valve stem. This allows both components to be extracted together from the valve body as one assembly, eliminating the need for separate removal steps and preventing the cage from becoming stuck in the valve body.
2Ease of repair
If the cage is removed separately after the valve plug, then individual component inspection is possible, but the cage frequently gets stuck in the valve body requiring additional lifting holes to be tapped
Solution Approach 1:
The patent merges the removal operation of the valve plug and cage into a single coordinated action. The lifting aperture in the cage allows the lifting tool (attached to the valve stem) to engage and pull both components out together, eliminating the need for separate removal operations and avoiding the complexity of tapping additional lifting holes.
Solution Approach 2:
The lifting aperture in the cage acts as an intermediary mechanism that connects the lifting tool to the cage structure. This intermediary feature enables the lifting force to be transmitted effectively to the cage without requiring direct engagement with the cage wall, thus preventing the cage from becoming stuck and eliminating the need for additional lifting holes.
3Power
If unbalanced valves are used with high inlet pressure, then valve performance is improved, but the valve seat becomes damaged due to fluid pressure crushing it
Solution Approach 1:
The patent segments the valve seat from the valve body by providing a separate valve seat assembly that can be independently removed with the trim assembly. This segmentation allows the valve seat to be replaced without replacing the entire valve body, thereby improving reliability by enabling quick replacement of damaged seats while maintaining the high-pressure performance capability of the unbalanced valve design.
Data Source
AI summary
A pressure regulator includes a valve body having a fluid inlet and a fluid outlet connected by a fluid passageway. An orifice is disposed between the fluid inlet and the fluid outlet. A valve seat is disposed within the fluid passageway. A movable valve plug is disposed within the fluid passageway, and the valve plug interacts with the valve seat to selectively open or close the fluid passageway. A cage is disposed in the fluid passageway, the cage surrounds the valve plug, and the cage includes a mechanical stop that limits movement of the valve plug within the cage away from the valve seat.