Plug Valve Preloaded Seal Segments Prevent Particulate Migration
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Solution Overview
Problem
Plug valves experience reduced seal performance due to fluid particulate migration between the plug member and seal segments, causing increased friction and accumulation, which diminishes the sealing effectiveness, especially when the plug valve is in a closed position.
Innovation Solution
A preloaded seal assembly is implemented, where side segments are tensioned between the inlet and outlet seal segments to prevent fluid migration, with the side segments and seal segments encircling the plug member to form a preload force that maintains a metal-to-metal contact, reducing friction and preventing particulate accumulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the plug valve is designed with traditional seal segments, then the structure is simple, but fluid particulate migrates between the plug member and seal segments causing increased friction and accumulation that diminishes seal performance
Solution Approach 1:
The seal assembly is divided into multiple functional segments: inlet seal segment, outlet seal segment, and side segments. Each segment performs a specific sealing function, with the side segments preventing particulate migration while the inlet and outlet seal segments provide primary sealing. This segmentation allows the system to maintain reliability while managing complexity through specialized components.
Solution Approach 2:
The side segments act as intermediary elements between the inlet and outlet seal segments, preventing fluid and particulate migration along the sides of the plug member. These intermediary components block the harmful flow path without interfering with the primary sealing function, thus improving reliability without excessive complexity.
2Ease of operation
If the plug member drifts in the axial direction during operation, then it enables fluid flow control, but causes gaps to form between the seal segment and plug member allowing particulate migration
Solution Approach 1:
The seal segments are designed with flexible elastomeric materials that can deform and maintain contact with the plug member during axial drift. The flexibility allows the seal segments to accommodate plug movement while maintaining sealing integrity, preventing particulate migration even when the plug drifts during operation.
Solution Approach 2:
The seal assembly is designed to dynamically adapt to plug member movement. The elastomeric seal segments can deform and reposition themselves as the plug drifts axially, maintaining continuous contact and sealing. This dynamic response ensures seal integrity is preserved during normal operational movements.
3Reliability
If the seal segments are made with elastomeric material, then they provide good sealing, but fluid pressure can cause plug drift that creates gaps for particulate migration
Solution Approach 1:
The side segments provide a counterbalancing force that opposes the fluid pressure-induced drift of the plug member. By blocking the side flow paths, the side segments reduce the unbalanced forces that cause axial drift, thereby maintaining seal contact and preventing particulate migration while allowing the elastomeric material to provide effective sealing.
Solution Approach 2:
The solution addresses the axial drift problem by adding functionality in the radial dimension. The side segments block radial and circumferential flow paths, preventing particulate migration from occurring even when axial gaps form due to drift. This dimensional approach prevents the harmful effect without restricting the necessary axial movement.
4Use of energy by moving object
If the plug valve operates under low pressure conditions, then energy consumption is reduced, but seal performance diminishes due to particulate accumulation
Solution Approach 1:
The side segments provide preliminary protection by blocking fluid and particulate migration paths before particles can accumulate at the seal interfaces. This preventive action occurs continuously during operation, including low-pressure conditions, maintaining seal performance without requiring additional energy input or high operating pressure.
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 preloaded seal assembly effectively prevents fluid and particulate migration between the plug member and seal segments, enhancing seal performance by maintaining a consistent metal-to-metal contact and reducing friction, even under low pressure conditions.
Implementation Method 1
the first and the second side segments are secured to and tensioned between the inlet seal segment and the outlet seal segment
Implementation Method 2
the side segments and seal segments encircle the plug member such that the side segments are tensioned to preload the seal segments against the plug member
Implementation Method 3
maintaining a consistent metal-to-metal contact and reducing friction
Data Source
AI summary
A plug valve including a valve body having an inlet port, an outlet port and a central chamber extending between the inlet port and the outlet port. The valve also includes an inlet seal segment within the central chamber and includes a bore extending therethrough and aligned with the inlet port. An outlet seal segment is disposed within the central chamber having a bore extending therethrough and aligned with the outlet port. A plug member is disposed in the central chamber and is moveable between an open position, to facilitate fluid flow through the plug valve, and a closed position, to block fluid flow through the plug valve. First and second side segments are disposed between and interlocked to the inlet and outlet seal segments to encircle the plug member. The side segments are tensioned to preload the seal segments against the plug member to prevent the flow of fluid between the seal segments and the plug member.