Composite Control Plate for Leak-Tight Proportional Valves
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Solution Overview
Problem
Existing fluid control valves in high-purity applications face challenges in achieving leak-tight shut-off and proportional control, particularly when using diaphragm-type designs, due to issues with polymer material moisture absorption and gas diffusion, and metal-to-metal designs struggle with cold welding and achieving good shut-off performance.
Innovation Solution
The use of a moveable valve element with a metallic control plate body and a softer material insert, such as a polymer or corrosion-resistant alloy, that is retained in a recess or groove, providing enhanced sealing by elastic deformation against the orifice ridge, and employing welding or interference fits to secure the components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a diaphragm-type design with polymer material is used, then proportional control is achieved, but moisture absorption and gas diffusion occur compromising high-purity performance
Solution Approach 1:
The valve is divided into two functional zones: a polymer diaphragm for proportional control operation and a metallic control plate for high-purity fluid contact. This segmentation allows each material to perform its optimal function while minimizing harmful effects.
Solution Approach 2:
Different materials are used in different locations: polymer where flexibility and control are needed (diaphragm), and metal where high purity and resistance to moisture/gas diffusion are critical (control plate and orifice ridge).
2Reliability
If a metal-to-metal design is used, then cold welding and poor shut-off performance are avoided, but leak-tight shut-off is difficult to achieve
Solution Approach 1:
The valve employs a composite material system combining polymer (for control), metal (for structural integrity and high-purity contact), and elastomeric materials (for sealing). This composite approach leverages the advantages of each material while mitigating their individual disadvantages.
Solution Approach 2:
An elastomeric material acts as an intermediary between the metallic control plate and the orifice ridge, enabling leak-tight sealing without direct metal-to-metal contact that causes cold welding.
3Reliability
If polymer material is extensively used in the control plate, then sealing is improved, but moisture absorption and gas diffusion increase
Solution Approach 1:
The control plate is segmented into a metallic body and a localized elastomeric sealing element. This segmentation confines polymer material to only where sealing is required, minimizing its exposure to high-purity fluid while maintaining sealing effectiveness.
Solution Approach 2:
Elastomeric material is applied locally at the sealing interface rather than throughout the entire control plate, providing sealing performance only where needed while reducing overall polymer exposure to process fluid.
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 configuration enhances leak-tightness and proportional control by minimizing polymer exposure, reducing moisture absorption, and avoiding gas diffusion, while ensuring effective shut-off performance without cold welding issues.
Implementation Method 1
Control plate materials being softer than the orifice ridge-lip allows elastic deformation of the control plate surface as it presses against the orifice ridge-lip and thereby enhances the sealing effected between the control plate and the orifice ridge-lip.
Data Source
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AI summary
A control plate for effecting superior shut-off in a proportional control valve comprises a moveable disk-shaped element that has a flat surface, generally perpendicular to the valve axis of symmetry when closed, and translates toward or away from an orifice surrounded by a narrow lip or orifice ridge. Enhanced leak tightness in the valve shut-off condition is achieved by selectively incorporating into the control plate materials that are softer than the material comprising the orifice ridge.