Middle-Supported Boiler Vertical Corner Columns
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Solution Overview
Problem
Designing middle-supported boilers poses a challenge in finding a simple and advantageous way to attach the middle section of the boiler pressure body to a rigid support steel structure while accounting for thermal expansion effects.
Innovation Solution
The boiler pressure body is middle-supported by vertical corner columns attached to the corner sections, with the support structure comprising multiple vertical main support columns and horizontal main support beams, allowing for adaptive connections to absorb thermal expansion, and the corner columns are attached at a height between 0.1 H to 0.9 H from the bottom, providing a high shear force capacity and reducing the need for strong walls.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of stationary object
If the boiler pressure body is supported at the middle section to a rigid support steel structure, then the size of the support steel structure is reduced compared to top-supported boilers, but the complexity of attaching the middle section while accounting for thermal expansion increases
Solution Approach 1:
The support system is segmented into multiple vertical corner columns at the four corners of the boiler pressure body, with each column independently attached to the rigid support steel structure. This segmentation allows the complex thermal expansion accommodation to be distributed across multiple simple connection points rather than requiring a complex overall attachment mechanism.
Solution Approach 2:
Instead of making the entire middle section attachment complex to accommodate thermal expansion, the patent uses simple rigid corner column attachments and allows the boiler pressure body walls themselves to flex and expand. The support structure remains simple and rigid, while the boiler body absorbs the thermal expansion effects.
2Strength
If vertical corner columns are attached to corner sections at middle height, then the shear force capacity is increased and wall strength requirements are reduced, but the attachment region must be carefully selected to provide sufficient height
Solution Approach 1:
The corner columns are attached to the corner sections during the initial manufacturing and assembly phase, with the attachment region pre-selected to be in a height range of at least 5% of the total boiler height. This preliminary positioning ensures sufficient attachment height is available before the boiler is put into service, eliminating the need for complex field modifications.
Solution Approach 2:
The corner sections themselves act as intermediaries between the vertical corner columns and the boiler pressure body walls. By attaching to the corner sections rather than directly to the main walls, the structure gains additional strength while simplifying the attachment process, as corner sections are naturally reinforced structural elements.
3Ease of manufacture
If the boiler pressure body walls are made strong enough to carry vertical compression load in bottom-supported construction, then the boiler can be bottom-supported, but the wall thickness and material requirements increase
Solution Approach 1:
The vertical compression load-carrying function is extracted from the boiler pressure body walls and transferred to the vertical corner columns and rigid support steel structure. This allows the walls to be designed for their primary function of containing pressure and accommodating thermal expansion, rather than also carrying compressive loads, thereby reducing wall thickness and material requirements.
Solution Approach 2:
Instead of making the walls strong enough to carry the entire vertical compression load (excessive action), the patent uses partial action by introducing corner columns that carry a portion of the load. This partial load transfer is sufficient to reduce wall strength requirements while maintaining overall structural integrity.
4Adaptability or versatility
If multiple vertical links are used to hang tubewalls from cantilever arms in middle-supported construction, then horizontal thermal expansion is absorbed, but the number of components and connection points increases
Solution Approach 1:
The thermal expansion accommodation is segmented into independent corner column units at each corner of the boiler, with each column providing local flexibility. This segmentation allows horizontal thermal expansion to be absorbed through simple local movements at each corner rather than requiring a complex system of multiple vertical links and cantilever arms.
Solution Approach 2:
The corner columns and boiler pressure body work together in a self-service manner where the corner columns provide the necessary support and the boiler body walls naturally accommodate thermal expansion through their inherent flexibility. No additional complex mechanisms are required - the system uses its own structural elements to handle thermal expansion.
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
This configuration allows for effective balancing of vertical loads, simplifies the boiler design, reduces the quantity of required steel structures, and facilitates faster erection while managing thermal expansion in both vertical and horizontal directions.
Implementation Method 1
In order to allow horizontal thermal expansion, the connection between the vertical corner columns and the rigid support steel structure has to be adaptive in all, or at least in all but one, horizontal directions.
Data Source
Figure 1
Figure 2a~2b
Figure 3a~3b
AI summary
A boiler construction (10) comprising a boiler pressure body (12) having a bottom (14) and a roof (16) at a height H from the bottom and at least four planar watertube walls (18) forming a polygonal horizontal cross section with at least four corner sections (20), and a rigid support steel structure (34), the boiler pressure body being supported to the rigid support steel structure at a height between the bottom and roof, wherein a vertical corner column (40) is attached exteriorly to at least four of the at least four corner sections (20) at a height region between the bottom and roof, and the supporting of the boiler pressure body (12) is provided by supporting each of the vertical corner columns (40) to the rigid support steel structure (34) at a height from 0.1 H to 0.9 H from the bottom so as to balance vertical loads of the boiler pressure body.