Composite Valve Plug Tip Bonding for Fracture-Resistant Shut-Off
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Solution Overview
Problem
Conventional ceramic valve plug tips used in severe service applications are prone to fracturing due to high actuator thrust forces and differing thermal expansion rates with metallic valve plug bodies, leading to reduced operational life.
Innovation Solution
A valve plug apparatus featuring a ceramic composite valve plug tip with a metallic matrix and an additively deposited metallic bonding layer, which spreads stress over a larger area and provides a mechanical connection, reducing the risk of cracking and fracture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If ceramic materials are used for valve plug tips to resist erosion, then resistance to erosive and corrosive effects is improved, but brittleness increases making the tip susceptible to fracturing under high actuator thrust forces
Solution Approach 1:
The valve plug tip is constructed as a composite structure combining ceramic material (for erosion and corrosion resistance) with a metallic bonding layer (for fracture resistance). The ceramic layer provides protection against erosive and corrosive process fluids, while the metallic bonding layer absorbs thermal expansion stress and prevents fracturing under actuator thrust forces, thus resolving the contradiction between erosion resistance and fracture resistance.
Solution Approach 2:
The invention changes the physical and chemical parameters of the valve plug tip by applying a metallic bonding layer with different thermal expansion properties than the ceramic material. This metallic layer has higher ductility and different thermal expansion characteristics that accommodate the thermal cycling and stress conditions, preventing the ceramic from fracturing while maintaining its erosion and corrosion resistance.
2Reliability
If high actuator thrust forces are applied to achieve tight shut-off, then sealing performance is improved, but stress concentrations in ceramic valve plug tips cause fracturing and cracking
Solution Approach 1:
The composite structure with metallic bonding layer provides a material that can withstand the high actuator thrust forces required for tight shut-off without fracturing. The metallic layer's ductility allows it to deform elastically under high load, distributing the stress and preventing the ceramic from cracking while maintaining the sealing contact with the valve seat.
Solution Approach 2:
The metallic bonding layer acts as a cushioning layer that absorbs and distributes the high actuator thrust forces before they reach the ceramic material. This pre-cushioning effect prevents stress concentrations that would otherwise cause fracturing, allowing the valve to achieve tight shut-off capability without compromising the ceramic tip's structural integrity.
3Duration of action of stationary object
If ceramic valve plug tips are used in severe service applications, then operating life is extended against erosion, but the tips fracture due to high loads and thermal expansion differences
Solution Approach 1:
The composite valve plug tip structure combines the erosion-resistant ceramic material with a metallic bonding layer that provides fracture resistance. This allows the valve plug to maintain both extended operating life in erosive environments and reliability under high thermal and mechanical loads, as the metallic layer compensates for thermal expansion differences and prevents catastrophic failure.
Solution Approach 2:
The metallic bonding layer serves as an intermediary between the ceramic valve plug tip and the metallic valve body. It mediates the thermal expansion differences between dissimilar materials and provides a transition zone that prevents stress concentrations, thereby extending operating life while maintaining reliability under severe service conditions.
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 solution significantly increases the resistance to fracturing and extends the operational life of the valve plug by distributing stress and providing a robust mechanical connection between the ceramic and metallic components.
Implementation Method 1
an additively deposited metallic bonding layer, which spreads stress over a larger area and provides a mechanical connection, reducing the risk of cracking and fracture
Implementation Method 2
an additively deposited metallic bonding layer, which spreads stress over a larger area and provides a mechanical connection
Data Source
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AI summary
An apparatus includin a valve plug tip (116), a valve plug body (114), and an additively deposited material (118). The valve plug tip includes a head portion (238) and a tail portion (240) extending from the head portion. The valve plug body includes a cavity (270) extending from a first end (216) of the valve plug body toward a second end (218) of the valve plug body. The cavity matably receives the tail portion of the valve plug tip. The additively deposited material is bonded to the valve plug body to retain the tail portion of the valve plug tip in the valve plug body.