Liquid Seal Compensation Duct for Thermal Expansion
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Solution Overview
Problem
Conventional furnace flue gas connections face challenges with thermal expansion, leading to misalignment and increased costs due to the need for larger, heavier, and more expensive toggle sections to maintain a gas-tight seal, which also result in a larger footprint and potential leaks.
Innovation Solution
A compensation duct assembly with a liquid seal between the connection duct and the backpass wall, allowing for thermal expansion compensation without the need for a toggle section, maintaining a gas-tight seal and reducing structural support requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional toggle sections are used to compensate for thermal expansion, then gas-tight connection is maintained, but the system becomes heavier and more expensive
Solution Approach 1:
The patent removes the conventional toggle section entirely and replaces it with a direct bolted connection between the compensation duct and backpass. The gas-tight seal is achieved through a water seal well and flexible element combination, extracting the expansion compensation function from the heavy toggle section while maintaining sealing reliability.
Solution Approach 2:
The patent uses a water seal well filled with liquid (water) to create a gas-tight barrier. The flexible element (such as a rubber or elastomeric membrane) works in conjunction with the water seal to maintain the gas-tight connection while accommodating thermal expansion movements, replacing the mechanical toggle section with a hydraulic/seal-based solution.
2Adaptability or versatility
If larger toggle sections are used to accommodate increased expansion, then thermal expansion compensation is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts the expansion compensation function from the complex toggle section mechanism and implements it through a simpler bolted connection with a water seal well and flexible element. This allows the connection to accommodate expansion movements without requiring the complex articulated structure of conventional toggle sections.
Solution Approach 2:
The patent employs a flexible element (such as a rubber or elastomeric membrane) that can deform to accommodate thermal expansion movements. This flexible element, combined with the water seal well, provides adaptability to expansion while maintaining a simple overall structure compared to large toggle sections.
3Reliability
If toggle sections are used to connect misaligned ducts, then gas-tight seal is maintained, but footprint and cost increase
Solution Approach 1:
The patent removes the toggle section that occupies significant space and replaces it with a compact bolted connection. The water seal well and flexible element combination provides gas-tight sealing in a much smaller footprint, eliminating the need for the extended structure of conventional toggle sections.
4Device complexity
If conventional bolted connections are used without toggle sections, then structure is simplified, but gas-tight seal during expansion is compromised
Solution Approach 1:
The patent uses a water seal well filled with liquid to create a gas-tight barrier that remains effective during thermal expansion. The flexible element (such as a rubber or elastomeric membrane) works in conjunction with the water seal to maintain the gas-tight connection while accommodating expansion movements, preventing leakage that would occur with simple bolted connections.
Solution Approach 2:
The patent employs a flexible element that can deform to accommodate thermal expansion movements while maintaining the gas-tight seal. This flexible element, combined with the water seal well, provides the necessary reliability for gas-tight connection during expansion without requiring the complex structure of conventional toggle sections.
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 compensation duct assembly effectively manages thermal expansion in three dimensions while minimizing costs and footprint, reducing the likelihood of leaks and supporting structural weight directly, thus providing a lighter, simpler, and more cost-effective gas-tight connection.
Implementation Method 1
a liquid seal (120) at the topside of the backpass end of a connection duct (110)
Implementation Method 2
When the backpass 9 and the flue gas ducts 1 expand, they move downward as shown by arrow 'A' and to the right, as indicated by arrow 'B'
Implementation Method 3
When air preheater duct 10 heats up, it expands upward in the direction shown by arrow 'C'
Data Source
Figure 1
Figure 2
Figure 3~6
AI summary
A compensations duct assembly [100] is described that provides a gas tight connection between a backpass of a furnace and an air preheater pipe [10] having one end fixed relative to a floor. The compensation duct assembly [100] has an air preheater opening that is connected to an air preheater duct [10]. A liquid seal [120] is employed to compensate for the movement due to thermal expansion between the backpass and the compensation duct assembly [100]. The liquid seal [120] provides a gas tight connection under various conditions of thermal expansion.