Short Stroke Flow Control Valve With Segmented Disk Stacks
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Solution Overview
Problem
Linear displacement control valves face limitations in maximum allowable stroke due to space or design constraints, particularly in applications with bellows seals for toxic or radioactive fluids, necessitating a solution for velocity control trim in short stroke configurations.
Innovation Solution
A short stroke flow control valve is designed with multiple disk stacks separated by spacers, featuring labyrinth grooves and seals to reduce leakage, and a plug with multiple throttling elements that control fluid flow through the disk stacks, allowing for custom characteristic curves and balanced or unbalanced configurations to accommodate specific applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional linear displacement valves are used with bellows seals for toxic or radioactive fluids, then reliability is improved, but the maximum allowable stroke is limited due to space constraints
Solution Approach 1:
The valve is divided into multiple disk stacks or cages arranged axially in series, each with its own flow control elements. This segmentation allows the total flow control function to be distributed across multiple shorter stages, achieving the required velocity control trim without requiring a single long stroke that would exceed space constraints while maintaining bellows seal reliability.
2Length of moving object
If multiple disk stacks are used to achieve velocity control trim in short stroke, then the stroke length is reduced, but the device complexity increases
Solution Approach 1:
Multiple disk stacks are combined within a single valve body, sharing common components such as the bonnet, stem, and actuation mechanism. This merging approach distributes the flow control function across multiple stages while avoiding the need for separate valve assemblies, thereby reducing overall complexity compared to using multiple individual valves or a single complex long-stroke valve.
3Manufacturing precision
If the plug lobes are made larger in diameter than the remainder of the plug, then flow control precision is improved, but manufacturing complexity increases
Solution Approach 1:
The plug is designed with localized variations in diameter, featuring larger-diameter lobes at specific positions where flow control is required, while the remainder of the plug maintains a smaller, simpler geometry. This local quality approach concentrates manufacturing precision requirements only where needed for flow control, rather than requiring the entire plug to be manufactured with high precision, thereby reducing overall manufacturing complexity.
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 valve provides velocity control trim equivalent to conventional valves in a short stroke, mitigating flow resistance and leakage, while allowing for customization based on application-specific requirements.
Implementation Method 1
The disk stacks or cages each feature labyrinth grooves and seals to reduce the leakage flow past the plug
Data Source
Figure 1
Figure 2
AI summary
A short stroke flow control device or valve which is adapted to provide velocity control trim in a short stroke The valve constructed in accordance with the present invention comprises multiple disk stacks or cages which are separated from each other by intervening spacers, and are placed axially in a valve gallery clamped between a seat ring and bonnet of the valve The fluid passageways in the cages are throttled in a controlled manner by a plug which defines multiple throttling elements or plug lobes, the number of plug lobes defined by the plug preferably being equal to the number of cages included in the valve The plug lobes of the plug control the flow of fluid through the disk stacks or cages in tandem.