Heat Shield Assembly Disk Spring Fastening
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Solution Overview
Problem
Existing fastening solutions for heat shield elements in combustion chambers of gas turbines face difficulties in easy installation and exchange of spring devices, particularly due to accessibility issues and inability to be pre-assembled for quick installation and subsequent removal.
Innovation Solution
A spring device with a receiving sleeve, abutment plate, and locking plate arrangement that allows pre-assembly and easy installation in the support structure, enabling quick installation and subsequent removal of spring elements, while preventing loosening during operation, using a combination of threaded and bayonet connections with guide flanges for secure fastening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sleeve with disk springs and pressure plate is used for fastening heat shield elements, then elastic fastening is achieved, but removal and exchange of spring elements becomes difficult due to accessibility issues
Solution Approach 1:
The spring device is divided into separable components: a receiving sleeve that remains in the support structure, and a removable assembly containing the abutment plate, spring elements, pressure plate, and locking plate. This segmentation allows the spring elements to be exchanged by removing only the removable assembly, solving the accessibility problem while maintaining elastic fastening reliability.
Solution Approach 2:
The spring elements are extracted from the fixed sleeve structure and placed in a removable assembly that can be taken out as a unit. The abutment plate with threaded hole and locking plate form a removable package that contains the spring elements, allowing easy removal and exchange without disturbing the receiving sleeve embedded in the support structure.
2Productivity
If disk springs are assembled in a sleeve for accelerated installation, then installation speed is improved, but the disk spring pack cannot be readily modified when required
Solution Approach 1:
The fastening system is segmented into a permanent receiving sleeve and a removable spring assembly. This allows the spring assembly to be pre-assembled for quick installation while enabling easy modification by removing the entire assembly, replacing spring elements, and re-installing.
Solution Approach 2:
The spring assembly is designed to be dynamically removable and re-installable, transforming the static fixed sleeve design into a flexible system that can be adapted as needed. The threaded connection and locking mechanism provide dynamic accessibility for modifications.
3Ease of operation
If the sleeve is open toward the combustion chamber interior, then disk spring pack removal is enabled by unscrewing the disk, but the pack cannot be screwed directly into the support structure in a pre-assembled state
Solution Approach 1:
Instead of opening the sleeve toward the combustion chamber interior, the sleeve is opened toward the rear side and equipped with a locking plate that secures the pressure plate. The abutment plate with threaded hole allows the entire assembly to be screwed into the support structure as a pre-assembled unit, while the locking plate enables easy removal from the rear side.
Solution Approach 2:
The abutment plate with threaded hole acts as an intermediary component that enables both functions: it allows the removable assembly to be screwed into the support structure in pre-assembled state, and provides a interface for the locking plate to secure and release the pressure plate, facilitating easy removal.
4Reliability
If spring elements are fastened securely to prevent loosening under thermal expansion and vibration, then fastening reliability is improved, but ease of exchange is reduced
Solution Approach 1:
The fastening system is segmented into a securely fixed receiving sleeve in the support structure and a removable assembly with locking mechanism. The locking plate secures the pressure plate and spring elements during operation to prevent loosening under thermal expansion and vibration, while the entire removable assembly can be easily detached as a unit for exchange.
Solution Approach 2:
The locking plate is designed to preliminarily secure the pressure plate and spring elements in the correct position before operation begins. This preliminary action ensures proper fastening under thermal load, while the removable design allows easy exchange when needed.
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
Facilitates simple and reliable fastening of heat shield elements, allowing for quick installation and exchange of spring devices, ensuring secure attachment even under high thermal expansions and vibrations, thereby enhancing the operational reliability of gas turbines.
Implementation Method 1
the spring element (49) which is arranged between the pressure plate (42) and the abutment plate (32)
Implementation Method 2
The abutment plate (32) is fastened in the receiving sleeve (21) in a removable manner
Implementation Method 3
using a combination of threaded and bayonet connections with guide flanges for secure fastening
Data Source
AI summary
A heat shield assembly of a combustion chamber has a supporting structure and heat shield elements arranged on the supporting structure. For fastening, the supporting structure has spring devices fastened therein, into each of which a fastening bolt can be screwed. In order to realize the pre-installation and the later removal of the spring elements contained in the spring device, at a holding sleeve, a contact plate is removably fastened in the holding sleeve on the side facing the heat shield element and a stationary securing plate is arranged on the opposite side.