Brush Seal Gasket Assembly for Turbomachine Concentricity Control
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Solution Overview
Problem
Existing sealing systems in turbomachines, such as carbon brush seals, suffer from geometrical defects like excessive flexibility and deformation during manufacturing and assembly, leading to poor concentricity, run out, and premature wear, which compromise sealing effectiveness and require frequent replacement.
Innovation Solution
A gasket assembly comprising a brush seal with a retaining ring and a bearing cover that holds the brush seal in position without compression, preventing rotation and reducing geometrical defects, allowing for proper operation and easy assembly/disassembly without plastic deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a brush seal is made flexible to adapt to clearance variations, then adaptability is improved, but manufacturing precision deteriorates due to excessive flexibility causing run out and eccentricity faults
Solution Approach 1:
The brush seal is segmented into multiple functional zones along its length: a toroidal core section for structural support, a skirt section for sealing contact, and a transition zone. This segmentation allows different sections to have different stiffness characteristics, with the toroidal area providing rigidity for concentricity while the skirt maintains flexibility for clearance adaptation.
Solution Approach 2:
Different regions of the brush seal are given different mechanical properties. The toroidal core area has higher rigidity to maintain concentricity and prevent run out, while the skirt section has appropriate flexibility to adapt to clearance variations. The bristle density and length are also varied locally to optimize both sealing performance and structural stability.
2Reliability
If compression is applied during assembly to secure the brush seal, then reliability is improved, but the brush seal suffers deformation and geometrical defects
Solution Approach 1:
The brush seal is pre-assembled with the retaining ring in a controlled environment to establish proper concentricity and geometric integrity before installation into the turbomachine. This preliminary assembly allows for precision alignment and eliminates the need for field compression that would cause deformation.
Solution Approach 2:
A retaining ring serves as an intermediary component between the brush seal and the housing bore. The retaining ring provides a rigid mounting structure that secures the brush seal without requiring compression of the seal itself, thereby maintaining the seal's geometric integrity while ensuring reliable positioning and sealing.
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 solution provides a solid assembly that maintains concentricity and prevents run out, ensuring effective sealing and extending the lifespan of the brush seal by eliminating the need for systematic compression during assembly and reassembly.
Implementation Method 1
a bearing cover (22), placed in contact with the brush seal (1) to hold it in position against the retaining ring (21), and prevent its rotation
Data Source
AI summary
An assembly forming a gasket for a turbomachine, includes a brush seal made of a plurality of sealing elastic bristles surrounding a core, a retaining ring including a recess to at least partly accommodate the brush seal, and a bearing cover, placed in contact with the brush seal to hold it in position against the retaining ring, the brush seal being located between the retaining ring and the bearing cover.