Expanding Gate Valve Wedge Mechanism for Wear Reduction
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Solution Overview
Problem
Conventional expanding gate valves experience significant wear and erosion due to premature wedging and back-wedging, leading to increased maintenance costs and operational resistance, as the gate members slide along seat surfaces during opening and closing movements.
Innovation Solution
The design features a pair of gate members supported by the valve stem during both opening and closing, with a wedge member that is only acted upon when it contacts a stop, ensuring equal balanced forces on tapered surfaces, preventing premature wedging and minimizing sliding friction, allowing for sequential opening movement of the upstream gate member before the downstream member.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional expanding gate valve geometry is used, then the gate members can be moved into sealing engagement with seat surfaces, but significant wear and erosion of seat and sealing surfaces occurs due to sliding during opening movement
Solution Approach 1:
The gate mechanism is divided into two separate gate members (first and second gate members) that can move independently. This segmentation allows the first gate member to remain stationary during initial opening while the second gate member moves, eliminating sliding friction on the seat surfaces and preventing wear and erosion while maintaining sealing engagement capability.
2Reliability
If conventional expanding gate valve geometry is used, then the gate members can be forced into sealing engagement, but significant drag and resistance occur causing the mechanism to stall before reaching closed position
Solution Approach 1:
The valve stem connection geometry is designed to dynamically change during operation. During closing movement, the valve stem initially moves only the second gate member while the first gate member remains stationary, minimizing drag. As closing progresses, the geometry transitions to move both gate members into sealing engagement, reducing resistance and preventing stalling.
3Ease of operation
If conventional expanding gate valve geometry is used, then the gate members can be moved linearly during opening, but the mechanism does not collapse causing continuous sliding contact with seat surfaces
Solution Approach 1:
The opening movement is segmented into two distinct phases: first, the second gate member moves linearly while the first gate member remains stationary; second, both gate members move together. This segmentation eliminates continuous sliding contact during the initial opening phase, preventing wear while maintaining ease of operation.
4Reliability
If conventional expanding gate valve geometry is used, then the gate members can be expanded mechanically, but premature expansion occurs before reaching closed position due to fluid pressure drag
Solution Approach 1:
The connection between the valve stem and gate members is designed with dynamic geometry that changes during closing movement. Initially, the geometry allows only the second gate member to move, preventing premature expansion. As closing progresses, the geometry transitions to enable both gate members to move and expand into sealing engagement, ensuring expansion occurs at the correct moment and preventing time loss.
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 reduces wear on seat and gate surfaces, minimizes the force required for opening, and prevents back-wedging, resulting in reduced maintenance costs and improved operational efficiency by ensuring balanced forces and minimal sliding friction during valve operation.
Implementation Method 1
a gate expansion wedge for gate expansion... camming interaction of the angular faces of the gate members, thus causing lateral expansion movement of the gate members
Implementation Method 2
both gate members are supported by the valve stem during both opening and closing movement
Data Source
AI summary
An expanding gate valve having a valve body defining a valve chamber and flow passages and having spaced sealing surfaces. Gate members are moveable within the valve body between open and closed positions and at the closed position having sealing engagement with the spaced sealing surfaces. A wedge member is positioned between the gate members and has at least one tapered surface having reacting engagement with a tapered surface of one of the gate members so that relative linear movement of the gate member relative to the tapered surface of the wedge member develops a lateral gate expansion force causing expansion of the gate members for tight sealing engagement with the spaced sealing surfaces. A valve stem is linearly moveable to valve opening and closing positions within said valve body and has driving connection with the gate members Upon initial linear opening movement the valve stem causes sequential opening movement of the gate members prior to initial opening movement of said first gate member and releases the sealing force of the upstream gate member to minimize the force that is required for opening for the valve.