Capillary Weld Extension Thermal Isolation for Vacuum Seal Outgassing
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Solution Overview
Problem
Remote seal systems in the process control industry face outgassing issues due to metallic construction, particularly at high temperatures, which affects their performance in vacuum applications, and existing solutions like high-temperature vacuum bakeout are impractical due to the complexity of remote seal configurations and materials used.
Innovation Solution
A capillary seal system with a capillary weld extension that is thermally isolated to reduce heat conduction, allowing the assembly to be baked out to eliminate trapped gases before use, thereby preventing outgassing, and this extension is designed to dissipate heat along its length to keep the weld connection below the outgassing temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high temperature vacuum bakeout is performed to eliminate outgassing, then outgassing is reduced, but the process time and equipment requirements increase significantly
Solution Approach 1:
The patent applies preliminary action by performing vacuum bakeout on individual remote seal components (seal body, capillary extension, diaphragm assembly) separately during manufacturing, before final assembly. This eliminates the need for time-consuming post-assembly bakeout, as the components are already degassed and ready for installation. The capillary tube is filled with seal fluid after assembly without requiring additional bakeout time.
Solution Approach 2:
The patent segments the remote seal system into separable components (seal body, capillary extension, diaphragm assembly) that can be independently baked out during manufacturing. This segmentation allows each component to be processed separately, reducing the overall process time compared to baking out the complete assembled system, while still achieving the required outgassing reduction.
2Reliability
If assembly bakeout is performed to eliminate weld outgassing, then outgassing is reduced, but the complexity and cost of manufacturing increase
Solution Approach 1:
The patent applies preliminary action by performing vacuum bakeout on the seal body and capillary extension assemblies separately during manufacturing, before final assembly with the diaphragm and capillary tube. This eliminates the need for complex post-assembly bakeout procedures, as the critical weld joints are already degassed. The capillary tube is filled with seal fluid after assembly without requiring additional bakeout.
Solution Approach 2:
The patent segments the manufacturing process into separate bakeout steps for different components (seal body assembly, capillary extension assembly) rather than requiring bakeout of the complete assembled system. This reduces manufacturing complexity by allowing standard oven equipment to be used for component-level processing rather than requiring specialized assembly bakeout capabilities.
3Ease of operation
If PVC armored capillary tube is used for flexibility and protection, then ease of installation is improved, but high temperature bakeout becomes ineffective
Solution Approach 1:
The patent segments the bakeout process from the capillary tube filling process. The seal body and capillary extension are baked out separately during manufacturing before the capillary tube is installed and filled with seal fluid. This allows the use of PVC armored capillary tubes (which cannot withstand high temperature bakeout) while still achieving effective outgassing reduction on the metal components that are baked separately.
Solution Approach 2:
The patent applies preliminary action by completing the vacuum bakeout of metal components (seal body, capillary extension) before final assembly and capillary tube installation. This timing allows the use of PVC armored capillary tubes that cannot withstand high temperature bakeout, while still achieving effective outgassing reduction on the critical metal components during the manufacturing process.
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 effectively reduces or eliminates outgassing from the weld joints and seal body, improving the accuracy and reliability of remote seal systems in high-temperature applications without requiring additional equipment or significant process time.
Implementation Method 1
A length of the extension is related to a temperature of the second end of the extension... the extension is designed to dissipate heat along its length to keep the weld connection below the outgassing temperature
Implementation Method 2
capillary weld extension with thermal isolation... thermally isolated to reduce heat conduction
Data Source
AI summary
A remote seal assembly includes a seal body and an extension. The seal body defines a cavity with a diaphragm that seals the cavity from a process fluid. The extension is connected with the seal body on a first end and is configured for connection to a capillary tube on a second end. The extension defines a bore extending from the first end to the second end that is fluidically coupled to the cavity. A length of the extension is related to a temperature of the second end of the extension such that the second end of the extension is at or below an outgassing temperature of the material used to connect the extension and the capillary tube.