Ring Preload Mechanism for Uniform Stress in Mated Pipes
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Solution Overview
Problem
Conventional methods for preloading joint systems require high external torque, which can damage components and are sensitive to lubrication and surface roughness, leading to non-uniform stress and poor repeatability, especially in large diameter systems.
Innovation Solution
A ring-shaped apparatus with adjustable preload mechanisms that can be removably attached to mated pipes, allowing for controlled preload application and release, reducing the need for high torque and improving uniformity of stress distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If conventional torqueing methods are used to preload joint systems, then the joint system can be preloaded, but high external torque is required which can damage components
Solution Approach 1:
The patent introduces a preload device as an intermediary mechanism between the torque application and the joint system. This device includes a reaction member that interfaces with a stationary structure and a preload member that applies force to the joint components, allowing preload application without directly torqueing the joint components themselves, thereby avoiding damage from excessive torque
Solution Approach 2:
The preload device is divided into separate functional components: a reaction member for anchoring, a preload member for applying force, and optional adjustment mechanisms. This segmentation allows the preload function to be separated from the joint assembly, enabling controlled force application independent of the joint's torque characteristics
2Force
If conventional torqueing methods are used, then preload can be applied, but frictions between adjacent surfaces resist the torqueing requiring special tools
Solution Approach 1:
The preload device acts as an intermediary that bypasses the frictional interfaces between joint components. By applying force through the preload member to the reaction member rather than torqueing the joint components directly, the device eliminates the need to overcome surface frictions, allowing standard tools to be used instead of special high-torque tools
3Force
If rotational movement is used to axially preload a component, then preload can be achieved, but non-uniform stress is created on mated components degrading reliability
Solution Approach 1:
Instead of using rotational movement to generate axial preload (the conventional approach), the patent inverts the mechanism by using direct axial movement of the preload member along its longitudinal axis to apply the preload force. This inversion eliminates the conversion from rotational to axial force that causes non-uniform stress distribution, resulting in more uniform loading of the joint components
4Force
If conventional torqueing methods are used, then preload can be applied, but the process is sensitive to lubrication and surface roughness resulting in poor repeatability
Solution Approach 1:
The preload device introduces intermediate interfaces (between the preload member and reaction member, and between the preload member and joint components) that are designed to be insensitive to the surface conditions of the joint components themselves. This decoupling allows precise control of the preload force through the adjustment mechanisms without being affected by variations in lubrication or surface roughness of the mated components
Solution Approach 2:
The patent incorporates adjustment mechanisms that allow precise control of the preload force by changing parameters such as the position of the preload member or the engagement of adjustment elements. This direct parameter control enables repeatable preload application independent of surface conditions, as the preload is determined by the adjustment mechanism settings rather than friction characteristics
Data Source
AI summary
An apparatus for providing a preload to mated pipes including a ring-shaped body formed by a sidewall and an attachment structure on a portion of the body. The ring-shaped body includes an aperture that extends through the sidewall. The attachment structure corresponds to an attachment portion of a pipe in the mated pipes and the attachment structure enables removable fastening of the body to the pipe. The apparatus may further include an adjustable preload mechanism that can be removably attached to the body to hold the body in a preloaded position. The preload mechanism can be adjusted to release a portion of the preload held by the body.