Sliding Stem Valve Plug Seal Gland for Low-Wear Shut-Off
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Solution Overview
Problem
Existing fluid valves with seals, such as sliding stem valves, face issues with seal degradation and wear due to high temperatures and friction, leading to leaks, maintenance needs, and costly repairs.
Innovation Solution
The design includes a seal gland in a sliding stem fluid valve with a first and second portion that changes dimension to displace a seal, reducing friction and wear by allowing the seal to compress and decompress during valve operations, and using means like a spring or passageways to guide and stabilize the movement of the valve plug.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a seal is used in a sliding stem fluid valve to prevent leaks, then sealing performance is improved, but seal wear and degradation occur due to high temperatures and friction
Solution Approach 1:
The seal gland is designed to be movable relative to the valve plug, allowing the seal to dynamically adjust its position and compression during valve operation. This dynamic design reduces continuous friction and thermal stress on the seal, extending its lifespan while maintaining sealing performance
Solution Approach 2:
The valve plug is divided into a first portion and a second portion, with the seal gland formed between them. This segmentation allows the seal to be isolated in a dedicated gland structure that can move independently, reducing the transmission of mechanical stress and heat from the main valve body to the seal
2Reliability
If the seal is compressed to ensure tight shut-off, then sealing performance is improved, but friction and wear on the seal increase
Solution Approach 1:
The seal compression is made dynamic rather than static. The movable seal gland allows the seal to be compressed only when needed for shut-off, and can decompress during operation, reducing continuous friction and wear while maintaining tight shut-off capability
Solution Approach 2:
The seal gland design provides a cushioning effect by allowing controlled movement and deformation of the seal. The gland structure absorbs and distributes the compression forces, preventing excessive stress concentration on the seal that would lead to premature wear
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 provides a tight shut-off of the fluid valve, reduces seal wear, and extends the seal's lifespan, minimizing maintenance and repair costs.
Implementation Method 1
When the second portion engages the seat, the first portion moves toward the second portion to reduce a volume of the seal gland to displace the seal toward the cage
Implementation Method 2
A spring is disposed between the first portion and the second portion, the spring to urge the first and second portions away from one another
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
Fluid flow control apparatus for use with fluid valves are disclosed. An apparatus includes a plug (202) for a sliding stem fluid valve. The plug has a first portion (210) slidably coupled to a second portion (214). The apparatus also includes a seal gland (241) formed in an outer circumferential surface of the plug by the first portion and the second portion. A dimension of the seal gland changes when the first portion slides relative to the second portion to displace a seal disposed in the seal gland. The seal sealingly engages a cage (226) of the fluid valve when the second portion contacts a seat (204) of the fluid valve.