Rotary Kiln Running Ring Structure for Thermal Expansion Relief
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Solution Overview
Problem
Rotary kilns face operational safety risks due to thermal expansion leading to high loads and mechanical stress on weld seams between the kiln shell and the supporting race, which can result in cracks despite rigorous execution and testing efforts.
Innovation Solution
A rotatable drum design featuring a circumferentially arranged running ring with projections interacting with fastening elements on the drum casing, allowing for thermal expansion without deforming the race, using a combination of form-fitting and material connections to distribute forces effectively and reduce stress on weld seams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a movable connecting assembly is used to accommodate thermal expansion of the kiln shell, then the drum can expand during operation, but the weld between the connecting assembly and the rotary kiln is subjected to high stress and may crack
Solution Approach 1:
The patent introduces a race as an intermediary component between the drum shell and the supporting structure. The race has projections that interact with fastening elements on the drum shell, creating a distributed connection system that mediates the thermal expansion forces and prevents direct stress concentration on single weld points.
Solution Approach 2:
The connection system is segmented into multiple discrete fastening elements distributed around the drum shell circumference. Each fastening element independently interacts with corresponding projections on the race, dividing the thermal expansion load into multiple smaller force vectors rather than concentrating stress on a single weld seam.
2Stability of the object's composition
If rigid welding is used to connect the race to the drum shell, then structural stability is improved, but thermal expansion causes high stress and potential cracks in the weld
Solution Approach 1:
The connection between the race and drum shell is made dynamic rather than rigid. The fastening elements can move relative to each other and to the race projections, allowing the structure to adapt to thermal expansion while maintaining overall stability. This dynamic connection prevents stress buildup that would occur in a rigid welded joint.
Solution Approach 2:
The patent changes the connection parameters from rigid fixed-position welding to movable fastening elements that can accommodate dimensional changes. The fastening elements are positioned to allow relative movement between the race and drum shell, changing the mechanical parameters from rigid to flexible connection.
3Stress or pressure
If multiple fastening elements are used to distribute forces, then stress on individual weld seams is reduced, but the complexity of the connection system increases
Solution Approach 1:
The patent combines multiple fastening elements with corresponding projections on the race into an integrated connection system. The projections on the race serve as both structural support elements and fastening mechanisms, merging the functions of support and attachment into a single component system that reduces overall complexity.
Solution Approach 2:
The race projections serve multiple functions: they provide structural support, act as fastening elements, and enable relative movement between the race and drum shell. This multi-functionality reduces the need for separate components, simplifying the overall connection system while achieving force distribution.
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 design enables safe operational thermal expansion of the drum shell by distributing forces across the entire cross-section, reducing the likelihood of weld seam cracks and enhancing operational reliability.
Implementation Method 1
very high temperatures arise within the rotary kiln when raw meal is burned to clinker, which lead to thermal expansion of the kiln shell
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The invention relates to a rotary drum (10) for processing materials, in particular bulk materials, having a drum shell (14) and a running ring (12) arranged circumferentially about the drum shell (14) for supporting the drum (10), wherein the running ring (12) has a plurality of protrusions (16) on the surface of the running ring facing radially inwards, said protrusions interacting with securing elements (22) attached to the drum shell (14), the drum shell (14) has a plurality of recesses (30), and a respective securing element (22) is attached in each recess. The invention also relates to a method for producing a drum with a rotary tube (11) and a running ring (12) arranged about the rotary tube (11), having at least the following steps: - introducing recesses (30) into the drum shell (14) of the rotary tube (11), - inserting a respective plate-shaped securing element (22) into each recess (30), - machining the securing element (22) arranged in the recess (30) so as to remove material, and - attaching the running ring (12) about the outer circumference of the rotary tube (11).