Fluoropolymer Welded Joint Layout for Low-Particle Liquid Contact
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Solution Overview
Problem
Existing welded bodies made from tetrafluoroethylene/fluoro(alkyl vinyl ether) or tetrafluoroethylene/hexafluoropropylene copolymers generate a significant number of particles when exposed to liquids with a solubility parameter of 14 to 35 (MPa) 1/2, which are difficult to wash away and contaminate chemical processes.
Innovation Solution
The welded body is designed such that the welded part is not exposed to the liquid contact surface by welding the tubes from the outer periphery, using a resin or heat-resistant tube to prevent the low molecular weight substance from adhering to the inner surface, thereby suppressing particle elution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If welded bodies are made from tetrafluoroethylene/fluoro(alkyl vinyl ether) or tetrafluoroethylene/hexafluoropropylene copolymers, then ease of manufacture is improved, but particle generation increases when exposed to liquids with solubility parameter of 14 to 35 (MPa) 1/2
Solution Approach 1:
The patent extracts the welded part from the liquid contact surface by designing a configuration where the welded portion is positioned on the outer surface or covered by a protective layer, thereby separating the harmful welded region from the liquid environment. This eliminates particle generation into the liquid while maintaining the manufacturing advantages of copolymer materials.
Solution Approach 2:
The patent applies different functional requirements to different parts of the welded body. The inner surface contacting liquid is designed with smooth, particle-free characteristics, while the welded portions on the outer surface can have different properties. This local differentiation allows use of copolymers for ease of manufacture while protecting the liquid contact surface from particle generation.
2Productivity
If welding is performed to connect molded bodies, then productivity is improved, but particle elution into liquid contact surface increases
Solution Approach 1:
The patent removes the welded part from the liquid contact surface by positioning welds on the outer surface or covering them with a protective layer. This allows welding to be used for connecting molded bodies (maintaining productivity) while preventing particle elution into the liquid.
Solution Approach 2:
The patent introduces an intermediary protective layer or design configuration between the welded part and the liquid contact surface. This intermediary prevents direct contact between the particle-generating welded region and the liquid, allowing both welding (for productivity) and particle-free liquid contact to be achieved.
3Ease of operation
If welded part is exposed to liquid contact surface, then ease of operation is improved, but particle contamination of chemical processes occurs
Solution Approach 1:
The patent extracts the welded part from the liquid contact surface, positioning it on the outer surface or covering it with a protective layer. This maintains ease of operation for the welded structure while preventing particle contamination of chemical processes by keeping the welded region away from liquid contact.
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 design significantly reduces particle elution into liquids, maintaining a particle count of 30 nm or larger to 1,000 particles/ml or less, particularly effective for chemical liquids used in semiconductor production.
Implementation Method 1
heating and melting a connecting part of a first molded body and a connecting part of a second molded body
Implementation Method 2
heating and melting a connecting part of a first molded body and a connecting part of a second molded body
Data Source
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AI summary
The present invention provides a welded body having a connecting structure formed by welding a first molded body and a second molded body, wherein the first and second molded bodies contain at least one copolymer selected from the group consisting of a tetrafluoroethylene/fluoro(alkyl vinyl ether) copolymer and a tetrafluoroethylene/hexafluoropropylene copolymer, and wherein the connecting structure has a liquid contact surface to be in contact with a liquid having a solubility parameter of 14 to 35 (MPa)1/2, a welded part formed in the connecting structure is not exposed to the liquid contact surface, and the number of particles of 30 nm or larger to be eluted from the liquid contact surface in the connecting structure is 1,000 particles/ml or less.