Annular Projection Pipe Joint for Seal Retention Under Nut Loosening
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Solution Overview
Problem
Existing pipe joints for high-purity liquids or ultrapure water systems fail to maintain sealing ability and prevent tube removal when the nut member loosens due to external factors or stress relaxation, leading to potential leakage and tube dislodgment.
Innovation Solution
A pipe joint design featuring a joint body with male threads and an extending shaft portion, along with a nut member having female threads, utilizes annular projections and tapered surfaces to securely grip the tube member, ensuring a stable seal and preventing inadvertent removal, even if the nut member loosens over time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the nut member is screw-advanced to grip the tube member, then the sealing ability is improved, but the nut member may become loosened due to external factors or stress relaxation
Solution Approach 1:
The tube member is expanded in diameter before insertion, creating a pre-formed gripping structure that will maintain constant contact pressure with the nut member and extending shaft portion throughout operation, preventing loosening due to stress relaxation
Solution Approach 2:
The tube member's diameter is changed through expansion, transforming it from a loose fit to a tightly gripping structure that maintains constant contact pressure, ensuring stable sealing ability even when the nut member is subjected to external factors or stress relaxation
2Reliability
If the gap between the back wall and opening edge is narrowed to improve sealing, then sealing ability is improved, but the structure becomes more complex
Solution Approach 1:
The joint structure is divided into distinct functional segments: the extending shaft portion with annular projections provides one sealing interface, while the nut member's inner circumferential surface provides another, allowing each segment to contribute to sealing without requiring complex integrated structures
Solution Approach 2:
The expanded diameter portion of the tube member acts as an intermediary element between the nut member and the extending shaft portion, creating a stable gripping structure that maintains constant contact pressure and simplifies the overall joint structure while ensuring reliable sealing
3Force
If the tube member is expanded in diameter to improve gripping, then the holding force is improved, but the insertion difficulty increases
Solution Approach 1:
The tube member is expanded in diameter in advance before insertion, creating a pre-formed gripping structure that will maintain constant contact pressure with the nut member and extending shaft portion throughout operation, preventing loosening due to stress relaxation
Solution Approach 2:
The tube member's diameter is changed through expansion, transforming it from a loose fit to a tightly gripping structure that maintains constant contact pressure, ensuring stable sealing ability even when the nut member is subjected to external factors or stress relaxation
Data Source
AI summary
A pipe joint includes a joint body formed with a through hole therein along an axial direction, and having male threads and an extending shaft portion formed on one end side thereof; and a nut member formed with an insertion hole through which a tube member is inserted, and having female threads formed therein that screw-engage with the male threads. Annular projections are formed on an outer circumferential surface of the extending shaft portion, and the tube member, which is expanded in diameter, is gripped between the annular projections and an inner circumferential surface of the nut member.