Threaded Joint Lip Portion Sealing Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Threaded joints for steel pipes, particularly those using wedge threads, face challenges in maintaining high sealing performance under high pressure conditions without compromising torque resistance, often resulting in fluid leaks due to inadequate sealing and potential plastic deformation.
Innovation Solution
A threaded joint design featuring a pin with a tapered male threaded portion and a lip portion, including a sealing surface with optimized geometry to enhance stiffness and prevent radial deformation, combined with a box having a corresponding recessed portion, provides both internal and external seals to ensure reliable sealing performance while maintaining high torque resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If wedge threads are used to provide high torque resistance, then torque resistance performance is improved, but sealing performance deteriorates under high pressure conditions
Solution Approach 1:
The threaded joint is segmented into two separate sealing mechanisms: thread seal (from wedge thread engagement) and internal seal (from lip portion contact). This segmentation allows each sealing mechanism to address different sealing requirements, with the internal seal specifically addressing high-pressure sealing where thread seal alone is insufficient.
Solution Approach 2:
The lip portion acts as an intermediary sealing element between the pin and box. It provides a dedicated sealing surface that contacts the recessed portion to form the internal seal, mediating the sealing function independently from the wedge thread engagement that provides torque resistance.
2Reliability
If manufacturing tolerances are strictly controlled to ensure thread seal, then sealing performance is improved, but manufacturing complexity increases
Solution Approach 1:
The sealing function is localized to specific regions: the thread seal is localized to the wedge thread engagement region, while the internal seal is localized to the lip portion and recessed portion contact region. This local quality approach allows different sealing mechanisms to operate in their respective optimal zones without requiring strict tolerances across the entire joint.
Solution Approach 2:
The invention changes the sealing parameter from relying solely on thread engagement geometry to including a separate contact pressure parameter at the lip portion-recessed portion interface. This parameter change allows sealing to be achieved through controlled contact pressure rather than strictly controlled manufacturing tolerances.
3Adaptability or versatility
If incomplete thread region is extended to accommodate drilling techniques, then adaptability is improved, but sealing performance deteriorates
Solution Approach 1:
The lip portion-recessed portion internal seal provides a universal sealing solution that works regardless of thread engagement length or completeness. This multi-functional sealing approach ensures sealing performance is maintained whether the joint uses full threads or incomplete threads, accommodating various drilling techniques.
Data Source
AI summary
A threaded joint is constructed of a pin and a box. The pin includes, in order from a tubular body having the pin toward the free end thereof: a male threaded portion and a lip portion including a sealing surface. The box includes: a female threaded portion corresponding to the male threaded portion of the pin; and a recessed portion corresponding to the lip portion, the recessed portion including a sealing surface. The lip portion includes, in order from a male threaded portion toward the free end of the pin: a neck portion; and a sealing head portion including the sealing surface. The maximum outside diameter of the region of the sealing surface in the sealing head portion is larger than an outside diameter of the neck portion at a boundary between the neck portion and the male threaded portion.