Lobed Polygonal Profile Tool Joint Connection
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Solution Overview
Problem
Current pipe connection methods, such as threaded connections and spline interlocks, fail to effectively transmit torque in both directions and often suffer from wear and failure due to reactive torque, leading to unreliable and durable connections in hydrocarbon drilling and production environments.
Innovation Solution
A tool joint connection system featuring a male and female connector with a lobed polygonal profile that corresponds to each other, allowing for non-rotatable engagement and secure transmission of torque across pipe sections, while also incorporating a tapered shape to facilitate sealing and reduce backlash.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If threaded connections are used between pipe sections, then the pipes can be joined together, but the connections cannot effectively transmit torque in both directions and may become unthreaded and separate
Solution Approach 1:
The connection uses asymmetric lobed profiles where the male connector has external lobes that engage with internal lobes of the female connector. This asymmetric geometry creates directional torque resistance, preventing both left and right rotation that would occur with symmetric threaded connections, thereby enabling reliable bidirectional torque transmission.
Solution Approach 2:
The connection employs curved lobed surfaces instead of straight threaded profiles. The lobes are formed with specific curvature radii that allow smooth engagement and distributed stress across the contact surfaces, enabling effective torque transmission while maintaining connection integrity under bidirectional rotational loads.
2Force
If spline interlocks are added to pipe ends, then torque can be transferred between sections, but the connections do not produce desired strength results and suffer from wear due to backlash
Solution Approach 1:
The connection features localized lobed engagement zones with optimized geometry and material properties. The lobes are positioned and dimensioned to concentrate strength where needed while maintaining overall connection integrity. This local optimization provides both the torque transmission capability and the strength required to withstand reactive torque without excessive wear.
3Adaptability or versatility
If standard pipe diameter standards are followed, then flow capacity and clearance expectations are maintained, but the joint sections have limits on sizes and thicknesses of materials used
Solution Approach 1:
The lobed connector design is configured to accommodate standard pipe outer diameters while providing a universal connection geometry that can be applied across different pipe sizes. The connector maintains compatibility with industry standard dimensions for flow capacity and clearance, while the lobed profile geometry provides the necessary torque transmission and strength without requiring non-standard material thicknesses.
Data Source
AI summary
A tool joint connection includes a first tool joint and a second tool joint. The first tool joint has a male connector portion with a lobed polygonal profile extending longitudinally from one end of the first tool joint toward an opposing end thereof. The second tool joint has a female connector portion having a lobed polygonal profile extending longitudinally from one end of the second tool joint toward an opposing end thereof. The lobed polygonal profile of the male connector portion corresponds to the lobed polygonal profile of the female so the male connector portion of the first tool joint is non-rotatably receivable in the female connector portion of the second tool joint to form a connection between the first tool joint and the second tool joint.