Split-Bolt Gas Line Connector to Prevent Galling Particles
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Solution Overview
Problem
Standard variable compression ratio fittings used in high temperature vacuum applications for gas lines are prone to galling, leading to the loosening and diffusion of silver particles into the gas lines, which are difficult to purge and can contaminate the system during processing in semiconductor manufacturing.
Innovation Solution
The use of connector assemblies comprising an inner bolt, a split outer bolt, and a clamp bolt, which are designed to prevent galling by positioning the threaded region away from the gas line opening, thereby minimizing the risk of particle contamination, and featuring a clamp bolt that holds the split outer bolt sections together to form a cylindrical bolt for secure connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If standard VCR fittings are coated with silver to prevent galling, then galling resistance is improved, but silver particles are loosened and diffuse into gas lines causing contamination
Solution Approach 1:
The fitting is divided into separate components: a body portion and a cap portion that can be independently manufactured and assembled. This segmentation allows the threaded regions to be positioned away from the gas line opening, preventing particle contamination while maintaining galling resistance through proper material selection and surface treatment of individual components.
Solution Approach 2:
The threaded regions are positioned in a different spatial dimension (away from the gas line opening) rather than at the connection point. This dimensional relocation ensures that threads do not contact the gas line interior, eliminating the source of particle contamination while preserving the structural integrity and galling resistance of the connection.
2Reliability
If special materials (silver, cobalt, chromium) are used to prevent galling in high temperature applications, then galling resistance is improved, but cost and complexity of fittings increase
Solution Approach 1:
Special materials or surface treatments are applied only to specific regions of the fitting where galling resistance is critical (such as the external threading surfaces), rather than coating the entire fitting. This localized approach maintains galling resistance in high temperature applications while reducing overall material complexity and cost.
Solution Approach 2:
Instead of coating the entire fitting with expensive materials, the design inverts the approach by using standard materials for the bulk structure and applying protective measures only where needed, or by designing the geometry to minimize contact between similar materials, thereby reducing complexity while maintaining reliability.
3Ease of operation
If threaded regions are positioned close to gas line opening for connection purposes, then connection functionality is improved, but particle contamination risk increases
Solution Approach 1:
The threaded regions are relocated to a different dimensional position (away from the gas line opening) on the fitting body. This spatial repositioning allows connections to be made externally without threads contacting the gas line interior, eliminating particle contamination risk while preserving full connection functionality through proper external threading design.
Data Source
AI summary
Connector assemblies for holding two tubes together and methods of use are described. The connector assemblies have an inner bolt, a split outer bolt comprising at least two outer bolt sections and a clamp bolt. The clamp bolt holds the outer bolt sections together to form the split outer bolt and the inner bolt is screwed into the outer bolt to enclose the two tube ends.