Premium Connection Torque Shoulder Geometry to Reduce Seal Galling
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Solution Overview
Problem
In threaded pipe connections, a large standoff between torque shoulders during the make-up process can lead to galling of seal surfaces, compromising the seal integrity, and existing designs are difficult to manufacture and control pin movement effectively.
Innovation Solution
The design features pin and box torque shoulders with multiple angled or curved surfaces that interact to secure the pin in place, reducing movement and deformation, and a method involving specific steps for forming these connections to ensure proper alignment and contact of seal and torque surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a large standoff between torque shoulders is maintained during make-up, then easier alignment is achieved, but galling of seal surfaces occurs compromising seal integrity
Solution Approach 1:
The torque shoulder is segmented into multiple surfaces (first and second torque shoulder surfaces) with different angles relative to the longitudinal axis. This segmentation allows different portions of the torque shoulder to perform different functions during the make-up process, enabling both alignment and seal protection.
Solution Approach 2:
Different regions of the torque shoulder have different local properties - the first torque shoulder surface has a first angle for alignment purposes while the second torque shoulder surface has a second angle for seal surface protection. This local differentiation allows optimization of each region for its specific function.
2Ease of manufacture
If existing torque shoulder designs are used, then manufacturing is simpler, but pin movement and deformation cannot be controlled effectively
Solution Approach 1:
The torque shoulder design allows for controlled deformation and movement during the make-up process. The multiple surfaces are designed to interact dynamically with corresponding surfaces on the box, progressively controlling pin movement as the connection is tightened.
Solution Approach 2:
The angles of the torque shoulder surfaces are specific parameters that can be adjusted to control pin movement. By changing these angular parameters, the design achieves effective movement control while remaining manufacturable using standard machining processes.
3Manufacturing precision
If multiple angled surfaces are added to torque shoulders, then pin movement control improves, but device complexity increases
Solution Approach 1:
The torque shoulder is divided into a small number of discrete surfaces (first and second surfaces) rather than using complex curved geometries. This segmentation achieves precise pin movement control while keeping the geometry simple enough for straightforward manufacturing.
Solution Approach 2:
Instead of using a single complex curved surface, the invention inverts the approach by using multiple flat planar surfaces. This inversion simplifies manufacturing while achieving the same or better control over pin movement through the angular relationships between surfaces.
Data Source
AI summary
A threaded tubular connection includes a pin having external threads, a pin seal surface, and a pin torque shoulder at a free end and a box for receiving the pin, the box having internal threads for interacting with the pin threads, a box seal surface for contacting the pin seal surface and a box torque shoulder for contacting the pin torque shoulder. The pin and box define a longitudinal axis. The pin torque shoulder has a first pin shoulder surface and a second pin shoulder surface, the first pin shoulder surface intersects an axis perpendicular to the longitudinal axis at a first angle and the second pin shoulder surface intersects the perpendicular axis at a second angle. The box torque shoulder has a first box shoulder surface and a second box shoulder surface. The first box shoulder surface intersects an axis perpendicular to the longitudinal axis at a third angle and the second box shoulder surface intersects the perpendicular axis at a fourth angle.