Steam Dryer Clamp Assembly for Vibration-Induced Weld Failures
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Solution Overview
Problem
Steam dryer lifting structures in nuclear reactors experience significant flow-induced vibrations leading to weld failures, cracking, and debris dispersion, posing risks of component detachment and environmental contamination.
Innovation Solution
A clamping system comprising multiple independent clamps that secure to lifting rod assemblies, limiting rotation between components and preventing vertical load transfer, using clamshell designs with adjustable hinges and bolts to ensure secure attachment without loose parts, and incorporating features like tabs and recesses to allow limited rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional welding and permanent securing methods are used to attach lifting components to steam dryer structures, then strong structural connection is achieved, but flow-induced vibrations cause weld failures, cracking, and debris dispersion
Solution Approach 1:
The lifting rod assembly is divided into separate modular components (lifting rod, lifting lug, clamps) that can be independently secured. The clamp system uses multiple independent clamps rather than a single welded connection, allowing each component to be separately attached and potentially replaced without affecting the entire assembly.
Solution Approach 2:
The connection method transitions from permanent welding to adjustable mechanical clamping. The clamps provide variable securing force that can be adjusted based on operational conditions, and the connection can be changed from fixed to movable, allowing the system to adapt to vibrational stresses without rigid constraint.
2Stability of the object's composition
If lifting components are permanently secured with rigid connections, then structural stability is improved, but rotation between components is prevented which may cause stress concentration and cracking under vibration
Solution Approach 1:
The clamp system allows controlled movement and rotation between components rather than rigid fixed connections. The clamps can accommodate slight movements and rotations, distributing stress dynamically rather than concentrating it at fixed weld points, thereby preventing cracking under vibrational loads.
3Reliability
If multiple independent clamps are used to secure lifting components, then reliability under vibration is improved and rotation is limited, but device complexity increases
Solution Approach 1:
The clamp design serves multiple functions simultaneously: it provides structural support, limits rotation, allows controlled movement, and distributes vibrational stresses. This multi-functionality reduces the need for additional specialized components, thereby managing complexity while achieving high reliability.
4Ease of operation
If traditional lifting rod assemblies are used without rotation limitation features, then ease of installation is maintained, but flow-induced vibrations cause uncontrolled rotation and component detachment
Solution Approach 1:
The clamp system incorporates self-limiting rotation features where the geometry of the clamp and lifting rod assembly automatically prevents excessive rotation without requiring external control mechanisms. The design inherently compensates for vibrational forces and maintains proper alignment, reducing the need for complex adjustment mechanisms during installation and operation.
Data Source
AI summary
Clamp systems include multiple, separate clamps joinable to components subject to relative rotation. Clamps may have similarly-positioned features to simplify installation and/or removal about a small area for all clamps in the system. Each clamp cannot freely rotate relative to an adjacent clamp but does not pass vertical loads to an adjacent clamp. Clamps may use mating shapes like an extension and recess to limit rotation. Clamps fit to the perimeters of components to which they individually secure by biasing against the components. At least one clamp has a transitional surface to provide space between the clamp and component to provide containment to a weld or other joining structure. Clamp systems can be tightened by included fasteners. Crimp nuts or other locking structures can preserve the biased and secured nature of the clamps and underlying structures. Clamp systems may be used to secure or repair a lifting rod assembly.