Composite Polyimide Seal for High-Temperature Fluid Tightness
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Solution Overview
Problem
Gas turbine engine seals face challenges in withstanding high temperatures while preventing fluid leaks, as existing materials like perfluoroelastomers degrade or release harmful compounds at temperatures above 550 degrees Fahrenheit.
Innovation Solution
The use of fiber reinforced polyimide resin layers, which are cured and then heated to conform to sealing surfaces, providing a fluid-tight seal that can withstand temperatures between 600 degrees Fahrenheit and less than 750 degrees Fahrenheit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If perfluoroelastomer seals are used to prevent fluid leaks, then sealing performance is improved, but the seal degrades or releases harmful compounds at elevated temperatures above 550 degrees Fahrenheit
Solution Approach 1:
The patent uses a composite sealing structure combining graphite material with PTFE (polytetrafluoroethylene) coating or impregnation. The graphite provides high-temperature structural stability and conformability to sealing surfaces, while the PTFE layer reduces friction and prevents fluid leakage. This composite approach allows the seal to withstand temperatures above 550°F without degrading or releasing harmful compounds, resolving the contradiction between sealing performance and thermal stability.
Solution Approach 2:
The patent changes the material composition parameters by transitioning from pure perfluoroelastomer to a graphite-PTFE composite system. This parameter change enables the seal to operate at elevated temperatures (above 550°F) by utilizing the high-temperature stability of graphite and the low-friction properties of PTFE, thereby preventing both degradation and harmful compound release while maintaining effective sealing.
2Temperature
If graphite or ceramic seals are used to withstand high temperatures, then temperature resistance is improved, but fluid leak prevention capability deteriorates due to less conformability
Solution Approach 1:
The patent creates a composite material system where graphite provides the high-temperature resistance and structural framework, while PTFE is incorporated as a coating or impregnation material that fills micro-gaps and enhances conformability to the sealing surfaces. This combination allows the seal to maintain both temperature resistance above 550°F and effective fluid leak prevention through improved surface conformity.
Solution Approach 2:
The patent applies different material properties to different regions or aspects of the seal: the bulk graphite structure provides high-temperature stability and mechanical strength, while the PTFE coating or impregnation provides local conformability and low-friction sealing contact. This local differentiation of material qualities enables simultaneous achievement of temperature resistance and fluid leak prevention.
3Reliability
If elastomeric seals are used to reduce fluid leaks, then sealing performance is improved, but the seal softens, degrades or yields decomposition products at elevated temperatures from 550 to 750 degrees Fahrenheit
Solution Approach 1:
The patent replaces the unstable elastomeric material with a graphite-PTFE composite. The graphite component provides thermal stability and structural integrity at temperatures from 550 to 750°F, while the PTFE component maintains low-friction sealing properties. This composite structure eliminates the softening and decomposition issues of elastomers while preserving effective fluid leak reduction.
Solution Approach 2:
The patent moves away from using disposable elastomeric seals that degrade at high temperatures by implementing a durable graphite-PTFE composite seal designed for long-term operation in elevated temperature environments. This replacement eliminates the need for frequent replacement due to thermal degradation while maintaining sealing effectiveness.
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 solution effectively prevents fluid leaks and maintains the integrity of the seal at high temperatures, while also allowing for the separation and reusability of components.
Implementation Method 1
at least one fiber reinforced polyimide resin layer is heated to between 600 degrees Fahrenheit and less than 750 degrees Fahrenheit (between 316 degrees Celsius and less than 399 degrees Celsius)
Implementation Method 2
after at least one fiber reinforced polyimide resin layer has cured
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
A method of sealing a first component (66;166;266;366;466) to a second component (68;168;268;368;468) comprising the steps of locating at least one fiber reinforced polyimide resin layer against a first sealing surface (72;172;272;372;472) on the first component (66... 466) and against a second sealing surface (74;174;274;374;474) on the second component (68...468). At least one fiber reinforced polyimide resin layer is compressed against the first sealing surface (72...472) and the second sealing surface (74...474) prior to curing at least one fiber reinforced polyimide resin layer. At least one fiber reinforced polyimide resin layer is heated to promote flow and conformation to the first sealing surface (72...472) and the second sealing surface (74...474). At least one fiber reinforced polyimide resin layer is cured to provide a fluid tight seal (70;170;270;370;470) between the first component (66...466) and the second component (68...468).