Threaded Connection Void Geometry to Prevent False Torque Shoulders
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Threaded connections in oil and gas pipelines often experience false torque shoulders due to squeezed thread compound, leading to loose connections and potential failures, especially in down-hole applications where the compound has no place to reside after make-up, causing the connection to back out.
Innovation Solution
The design incorporates void spaces between pin and box threads, allowing thread compound to be disposed within these voids upon make-up, ensuring accurate engagement and maintaining a tight connection without requiring a torque shoulder, thereby preventing false torque shoulders and ensuring a secure connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If standard threaded geometry is used, then manufacturing is simplified, but thread compound has no place to reside causing connections to back out
Solution Approach 1:
The thread geometry is segmented to create discrete void spaces between adjacent threads. This segmentation provides specific zones for compound residence without requiring complete redesign of the thread form, maintaining manufacturing simplicity while improving connection stability through proper compound containment.
Solution Approach 2:
The solution adds a radial dimension to the thread design by creating void spaces between threads, rather than changing the axial thread pitch or profile. This dimensional approach allows compound containment without significantly complicating the manufacturing process, as the void spaces are formed by radial clearance rather than complex machining.
2Ease of operation
If thread compound is squeezed from threads during make-up, then thread lubrication is improved, but false torque shoulders appear affecting torque accuracy
Solution Approach 1:
The harmful effect of compound squeeze-out is extracted and redirected into designated void spaces between threads. By providing specific zones for compound residence, the design removes compound from the torque transmission path, eliminating false torque shoulders while maintaining the lubrication benefits during make-up operation.
Solution Approach 2:
The compound that would normally cause harm by creating false torque shoulders is converted into a beneficial element by directing it into void spaces where it can continue to provide lubrication and sealing without interfering with torque measurement. The harmful squeeze-out is transformed into controlled compound placement that benefits both lubrication and torque accuracy.
3Shape
If integral flush connections are used, then connection outer and inner diameters remain flush, but tension efficiency is limited to 68-72%
Solution Approach 1:
The threaded connection design nests void spaces within the thread structure itself, allowing the connection to maintain a compact, flush geometry externally while incorporating internal features (void spaces) that enhance performance. This nesting approach allows improved tension efficiency through better compound containment while preserving the desired flush outer and inner diameters.
Data Source
AI summary
A threaded connection including a pin with a plurality of pin threads, the plurality of threads comprising a plurality of pin crests and pin roots; and a box with a plurality of box threads, the box threads comprising a plurality of box crests and box roots, where the plurality of box roots and the plurality of pin crests are parallel to a horizontal axis, and where the plurality of pin roots are parallel to and collinear with a pin root taper plane, the pin root taper plane being not parallel to the horizontal axis creating at least one void space upon make-up of the threaded connection between the plurality of pin crests and the plurality of box roots, and at least one void space upon make-up between the plurality of pin roots and box crests.