Lifting Frame with Variable Wall Thickness for Transformer Handling
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Solution Overview
Problem
The existing methods for lifting transformers and reactors are inefficient and pose safety risks due to oversizing of lifting equipment, manual alignment challenges, and potential failure from horizontal force components, which complicates safe transportation and handling.
Innovation Solution
A lifting frame design with a frame wall section that increases in thickness towards the lifting opening, providing a larger contact area and reducing stress, while allowing for vertical alignment and minimizing horizontal forces, thus eliminating the need for manual adjustments and oversizing of equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If commercial pad-eyes and standardized lifting eyes are used, then manufacturing costs are reduced and standardization is achieved, but the lifting equipment becomes oversized and requires additional structural support to handle horizontal forces
Solution Approach 1:
The frame wall section has non-uniform thickness distribution, being thicker near the lifting opening and thinner toward the edges. This local variation in thickness provides sufficient strength and stiffness at the critical lifting opening area while reducing material usage and overall weight in less critical regions, thereby avoiding oversizing of the entire lifting construction.
Solution Approach 2:
The lifting frame design inherently accommodates horizontal force components through its structural configuration and the thickness variation of the frame wall section, eliminating the need for additional stabilization structures or manual alignment adjustments during operation.
2Ease of manufacture
If standardized lifting eyes are used, then manufacturing costs are reduced, but the dimensions may not be compatible with specific lifting requirements and manual alignment becomes necessary
Solution Approach 1:
The frame wall section is designed with optimized local thickness characteristics that provide inherent alignment and positioning capabilities at the lifting opening, eliminating the need for manual alignment adjustments while maintaining manufacturing efficiency through standardized processes.
3Reliability
If tie-rods and lifting chains are selected to fit standardized lifting eyes with high safety factors, then safety is ensured, but significant over-design and weight increase occur
Solution Approach 1:
The frame wall section concentrates material thickness locally at the lifting opening where it is most needed for load bearing and safety, while using thinner sections elsewhere. This optimized distribution provides the required safety factor at critical points without the unnecessary weight and material cost of uniformly thick designs.
Solution Approach 2:
The design changes the thickness parameter of the frame wall section continuously or in steps from the lifting opening outward, creating an optimal balance between safety requirements and weight minimization that avoids over-design of the entire lifting system.
Data Source
AI summary
A lifting frame for lifting a transformer or reactor is provided that includes a frame wall section. The frame wall section extends within a frame wall section plane. A lifting opening is formed within the frame wall section, wherein a lifting opening axis is oriented normal with respect to the frame wall section plane. The frame wall section immediately surrounding the lifting opening has a thickness that increases with decreasing distance to the lifting opening axis. This construction allows for providing an edge of the lifting opening with a comparatively large surface or contact area, while avoiding an overdesign of the frame wall section thickness. An increase in the surface of the edge generally reduces a contact pressure.