Knife Gate Valve Liner Bead Structure for Bi-Directional Sealing
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Solution Overview
Problem
Existing knife gate valves with one-piece liners are prone to wear and tear, leading to the valve being discarded once the liner is worn out, as they lack effective sealing mechanisms for bi-directional flow and differential pressure resistance.
Innovation Solution
A knife gate valve design featuring a valve body assembly with flange recessed portions and a one-piece liner that includes radial sealing beads with varying protrusion heights, allowing for effective sealing against the gate and enabling bi-directional flow, while the liner can be reused as it is designed to withstand differential pressure and abrasive/corrosive process fluids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a one-piece liner is used to line the valve body, then the valve body is protected from wear, but the entire valve must be discarded when the liner wears out
Solution Approach 1:
The liner is divided into multiple segments or sections that can be independently replaced. Each segment can be removed and replaced without replacing the entire liner assembly, allowing selective replacement of worn sections while retaining the valve body and other functional components.
Solution Approach 2:
The liner segments are designed to be disposable or replaceable components while the valve body is recovered and reused. When liner segments wear out, only those specific segments are discarded and replaced, while the valuable valve body structure is retained for continued service.
2Device complexity
If a one-piece liner is used, then the valve structure is simplified, but the sealing capability against differential pressure is insufficient
Solution Approach 1:
The liner is segmented into multiple sections with intermediate sealing elements between segments. This segmentation allows for better pressure distribution and sealing at each interface, improving the overall sealing capability against differential pressure while maintaining a relatively simple overall structure.
Solution Approach 2:
Intermediate sealing elements or beads are introduced between liner segments to act as mediators that enhance sealing capability. These intermediary components fill gaps and prevent leakage paths, improving sealing performance without requiring complete redesign of the liner structure.
3Reliability
If the liner protrudes into the flow path, then sealing against the gate is improved, but flow capacity is reduced
Solution Approach 1:
The liner is designed with varying protrusion heights at different locations. Higher protrusions are positioned where sealing against the gate is critical, while lower or recessed sections are positioned in the main flow path to minimize flow restriction. This local differentiation optimizes both sealing performance and flow capacity.
Solution Approach 2:
The liner design incorporates dimensional variations in the radial direction, creating a profile that transitions from higher protrusions near the sealing interface to lower protrusions in the flow path. This dimensional transition allows the liner to provide effective sealing while maintaining adequate flow capacity through strategic height variation.
Data Source
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AI summary
Embodiments of the invention provide a knife gate valve including a valve body assembly defining a passageway having an axis and including a first body half and a second body half each including a flange recessed portion defining a flange recess surface. Each flange recess surface includes a first flange surface portion, a second flange surface portion, and a raised flange bead between the first flange surface portion and the second flange surface portion. The knife gate valve further includes a one-piece liner arranged between the first body half and the second body half, and including a first liner flange engaged with the first flange surface portion, the raised flange bead, and the second flange surface portion of the first body half, and a second liner flange engaged with the first flange surface portion, the raised flange bead, and the second flange surface portion of the second body half.