Circular Locking Seal Geometry for Variable Make-Up Threaded Joints
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Solution Overview
Problem
Existing threaded connections with indeterminate make-up positions, such as those using wedge threads, face challenges in maintaining a robust seal due to uncertainty in the relative position of sealing surfaces during assembly.
Innovation Solution
A threaded connection design featuring a first tubular member with a convex circular sealing surface and a second tubular member with a concave circular sealing surface, where the two sealing surfaces have different radii, ensuring a seal over a range of relative axial positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a threaded connection uses an indeterminate make-up position design (e.g., wedge threads), then the connection allows for easier assembly and adjustment, but the relative position of sealing surfaces becomes uncertain, compromising seal robustness
Solution Approach 1:
The patent employs asymmetric sealing surfaces where the first sealing surface has a different radius of curvature than the second sealing surface. This asymmetric geometry ensures that regardless of the relative axial position achieved during assembly, the convex and concave surfaces will always contact at a specific point, maintaining seal robustness while allowing indeterminate make-up position.
Solution Approach 2:
The patent utilizes curved sealing surfaces with specific radii of curvature. The first sealing surface has a first radius of curvature and the second sealing surface has a second radius of curvature, where the ratio between these radii is controlled. This curvature design ensures point contact between sealing surfaces across a range of relative axial positions, maintaining sealing effectiveness without requiring precise positioning.
2Reliability
If a threaded connection uses a torque shoulder design with determinate make-up position, then the final relative position of components is known and seal location is certain, but the design complexity increases and assembly flexibility is reduced
Solution Approach 1:
Rather than adding a torque shoulder feature, the patent uses asymmetric curved sealing surfaces to achieve reliable sealing. The different radii of curvature of the two sealing surfaces create a deterministic contact point without requiring additional positioning features, thus maintaining seal location certainty while reducing design complexity.
Solution Approach 2:
The patent controls the ratio between the radii of curvature of the two sealing surfaces. By specifying that this ratio falls within a particular range, the design ensures proper sealing contact across a range of relative axial positions, achieving reliable sealing through parameter optimization rather than additional structural features.
3Ease of manufacture
If sealing surfaces have the same radius, then the geometry is simpler to manufacture, but the seal may not maintain robust contact over a range of relative axial positions
Solution Approach 1:
The patent specifies that the two sealing surfaces have different radii of curvature, with the ratio between them controlled within a specific range. This asymmetric geometry ensures that the convex and concave surfaces will contact at a defined point regardless of the exact relative axial position achieved during assembly, maintaining seal robustness while keeping manufacturing relatively simple.
Solution Approach 2:
The patent optimizes the ratio between the radii of curvature of the two sealing surfaces. By controlling this parameter ratio rather than requiring exact radius values, the design achieves reliable sealing contact over a range of positions while maintaining ease of manufacture through standardized geometric relationships.
Data Source
AI summary
A threaded connection includes a first tubular member comprising a convex circular sealing surface with a first seal radius and a second tubular member comprising a primary concave circular sealing surface with a second seal radius. The first seal radius and second seal radius are preferably different, with the second seal radius more preferably being larger than the first seal radius. The second tubular member may also comprise a second concave circular surface with a third radius that is smaller than the second seal radius. The second tubular member may also comprise a frontside angled surface forming an angle as measured from the longitudinal axis of the connection.