Dual-Seal Assembly for Compressor Shutdown Leak Prevention
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Solution Overview
Problem
Conventional mechanical seals in compressors experience leaks when the compressor is stopped due to temperature increases and pressure buildup, leading to weight and bulk issues in weight-sensitive applications like aviation.
Innovation Solution
A sealing assembly with a primary seal and a secondary seal, where the primary seal is engaged during rotation and the secondary seal is engaged when the compressor is stationary or rotating below a threshold speed, using a resilient flexible seal with an extension member that disengages from the second seal ring at higher rotational speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a hermetically sealed shell is added to prevent leaks, then leakage prevention is improved, but weight and bulk increase
Solution Approach 1:
The sealing system is divided into two independent seals: a dynamic seal for operational sealing and a secondary static seal for shutdown sealing. This segmentation allows each seal to be optimized for its specific function without requiring a heavy hermetic enclosure, thus preventing leaks while maintaining weight efficiency in aviation applications.
2Reliability
If a secondary seal is added to prevent shutdown leaks, then leakage prevention is improved, but device complexity increases
Solution Approach 1:
The secondary seal incorporates an extension member that dynamically changes its sealing engagement based on rotational speed. At low speeds and during shutdown, the extension member engages with the second seal ring to prevent leaks. At high speeds, centrifugal force causes the extension member to disengage, avoiding interference with the dynamic seal. This dynamic behavior provides comprehensive leakage prevention without requiring complex control systems or additional actuating mechanisms.
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 sealing assembly effectively prevents leaks during both operational and nonoperational cycles of the compressor, maintaining fluid containment and reducing wear on the seals, thus addressing the weight and bulk concerns in aviation applications.
Implementation Method 1
the extension member is configured to disengage from the second circumferential surface when the first seal ring is rotating, relative to the second seal ring, at or above a threshold speed
Data Source
AI summary
A sealing assembly and associated shaft assembly is disclosed. The sealing assembly comprises a primary seal at a sealing interface between a first sealing face of a first seal ring and a second sealing face of a second seal ring. The sealing assembly also comprises a secondary seal between an extension member of a resilient flexible seal and a second circumferential surface of the second seal ring. The resilient flexible seal is coupled to the first seal ring. The first seal ring is rotatable, relative to the second seal ring, and the extension member is configured to disengage from the second circumferential surface of the second seal ring when the first seal ring is rotating, relative to the second seal ring, at or above a threshold speed.