Well String Turnbuckle Locking With Compression Washer
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Solution Overview
Problem
In subsea well strings, turnbuckles used to connect components like housing and lower end caps tend to rotate and vibrate, leading to partial disengagement due to opposing thread directions, causing unreliable connections and potential separation under operational conditions.
Innovation Solution
A connection system employing a turnbuckle with opposing thread directions and a compression washer that applies a longitudinal force to increase resistance to rotation, coupled with radial set screws and specific thread types like stub Acme threads, to secure the lower end cap to the housing and prevent unintentional disengagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a turnbuckle with opposing thread directions is used to connect the housing and lower end cap, then the connection can be tightened and maintained, but rotation and vibration cause the turnbuckle to rotate in the opposite direction, leading to partial disengagement
Solution Approach 1:
A compression washer is introduced as an intermediary element between the turnbuckle and the housing. The washer applies a compression force to the turnbuckle, increasing friction between the turnbuckle threads and the housing threads, thereby preventing unintended rotation and disengagement while maintaining the connection strength provided by the turnbuckle.
Solution Approach 2:
The compression washer is pre-installed and pre-compressed between the turnbuckle and housing before operational vibrations occur. This preliminary compression establishes sufficient friction force to counteract the vibrational forces that would otherwise cause the turnbuckle to rotate in the opposite direction and disengage.
2Ease of operation
If the turnbuckle is rotated to draw the lower end cap toward the housing for engagement, then the connection is established, but operational vibrations drive the turnbuckle to rotate in the opposite direction causing disengagement
Solution Approach 1:
The compression washer serves as a mediator that maintains the engaged position of the lower end cap to the housing. By applying continuous compression force to the turnbuckle, it creates sufficient friction to prevent the turnbuckle from rotating backward during operation, thereby stabilizing the connection while allowing easy assembly through simple rotation.
3Ease of manufacture
If standard threads are used on the turnbuckle, then assembly is simple, but friction is insufficient to prevent rotation under vibration
Solution Approach 1:
The compression washer is introduced as a mediator to augment the friction force. Instead of manufacturing complex high-friction threads, the simple compression washer applies axial compression force to the turnbuckle, which translates to increased friction between the threads. This maintains ease of manufacture while solving the insufficient friction problem.
Solution Approach 2:
The compression force is applied in advance through the pre-installed compression washer, creating sufficient friction force before operational vibrations occur. This preliminary friction enhancement prevents the turnbuckle from rotating under vibration without requiring complex thread designs.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system effectively reduces the likelihood of unintentional separation of components, enhancing the reliability and stability of connections within subsea well strings by increasing friction and resistance to rotational forces from vibrations and operations.
Implementation Method 1
A compression washer is disposed about the housing and configured to apply a longitudinal force to the turnbuckle to increase friction
Implementation Method 2
The threads of the turnbuckle may be engaged with the threads of the housing and the threads of the lower end cap. Rotation of the turnbuckle in a first direction draws the lower end cap toward the housing
Data Source
AI summary
A connection system includes a turnbuckle having a first set of threads and a second set of threads disposed on an inner surface of the turnbuckle. The turnbuckle is configured to couple two threaded components to one another via rotation of the turnbuckle in a first direction. In addition, the connection system includes a compression washer configured to compress as the turnbuckle rotates in the first direction. The compression washer is configured to apply a longitudinal force to the turnbuckle while the compression washer is compressed to increase resistance to rotation of the turnbuckle in a second direction, opposite the first direction.