Dynamic Valve Trim Joints for Thermal Expansion Control
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Solution Overview
Problem
Control valves in high-temperature applications face challenges due to differing coefficients of thermal expansion among components, leading to distortion and assembly complications, particularly with the seat ring, which requires labor-intensive machining to maintain sealing engagement.
Innovation Solution
A dynamic joint between the cage retainer and bonnet allows for relative movement to accommodate thermal expansion, using a steel material for the cage retainer with a lower coefficient of thermal expansion than the bonnet and cage, and incorporating projections made of a different material to prevent corrosion and maintain the dynamic joint, eliminating the need for fasteners to secure the seat ring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If different materials are used for control valve components, then functional performance is improved, but thermal expansion distortion increases
Solution Approach 1:
The patent changes the material parameter (coefficient of thermal expansion) by selecting specific materials for the cage retainer and bonnet that have matched thermal expansion characteristics, thereby resolving the distortion issue while maintaining functional performance
Solution Approach 2:
The patent uses composite construction with a cage retainer made of a first material and a bonnet made of a second material, where the materials are specifically selected to have compatible thermal expansion properties, allowing functional differentiation without thermal distortion
2Strength
If fasteners are used to secure the seat ring, then assembly strength is improved, but assembly complexity and labor increase
Solution Approach 1:
The patent removes the fasteners from the assembly, eliminating the need for machining operations while maintaining the structural integrity through the dynamic joint design between the cage retainer and bonnet
Solution Approach 2:
The dynamic joint between the cage retainer and bonnet self-adjusts to maintain proper seating of the seat ring without requiring external fastening elements, thereby simplifying assembly while maintaining strength
3Stability of the object's composition
If rigid joint is used between cage retainer and bonnet, then structural stability is improved, but thermal expansion accommodation is reduced
Solution Approach 1:
The patent employs a dynamic joint between the cage retainer and bonnet that allows relative movement, enabling the assembly to adapt to thermal expansion while maintaining structural stability through controlled flexibility
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 thermal expansion, simplifies assembly and disassembly, prevents distortion of the seat ring, and maintains sealing engagement without fasteners, enhancing the operational reliability and maintenance of fluid valves.
Implementation Method 1
different components of the control valve are made of different materials having different coefficients of thermal expansion. As such, in high temperature applications, the coefficients of thermal expansion of the materials from which the different control valve components are made have to be taken into account
Implementation Method 2
incorporating projections made of a different material to prevent corrosion and maintain the dynamic joint
Data Source
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AI summary
Fluid valves having dynamic valve trim joints are described. An example apparatus for use with a fluid valve includes a body configured to retain a cage of a fluid valve. Additionally, the example apparatus includes a plurality of projections projecting from and radially spaced about an exterior surface of the body. Each of the plurality of projections is to provide one or more contact points between the body and an inner surface of a bonnet coupled to the fluid valve.