Secondary Seal Alignment Tabs for Non-Contact Seal Assembly
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Solution Overview
Problem
Rotational equipment faces inefficiencies and high manufacturing costs due to heat generation and stress from traditional contact seals, while non-contact seals can be difficult to assemble and prone to stress concentrations.
Innovation Solution
A non-contact seal assembly for rotational equipment featuring a primary hydrostatic seal device with arcuate seal shoes and spring elements, along with secondary seal devices, which are mounted using alignment tabs to simplify installation and reduce stress, effectively sealing the annular gap between stator and rotor structures without direct contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If contact seals with seal elements are used, then sealing performance is improved, but heat generation and stress increase significantly
Solution Approach 1:
The patent replaces the mechanical contact seal system with a non-contact magnetic seal system. The magnetic seal uses magnetic fields to hold the seal element in position and maintain sealing without physical contact, thereby eliminating the friction and heat generation inherent in mechanical contact seals while maintaining sealing performance.
2Temperature
If non-contact seals are used, then heat generation is reduced, but assembly difficulty and stress concentrations increase
Solution Approach 1:
The patent incorporates preliminary alignment features directly into the seal component design, specifically alignment tabs that protrude from the seal element and correspond to recesses in the housing. This preliminary alignment action is built into the component geometry, allowing the seal to self-align during assembly without requiring complex external alignment tools or procedures, thereby reducing assembly difficulty.
Solution Approach 2:
The alignment tabs act as intermediary elements between the seal element and the housing. These tabs engage with corresponding recesses to provide mechanical guidance and positioning during assembly, serving as an intermediary mechanism that facilitates the connection between the magnetic seal and housing without requiring direct complex mating of the main sealing surfaces.
3Temperature
If non-contact seals are used, then heat generation is reduced, but stress concentrations during operation increase
Solution Approach 1:
The alignment tabs provide preliminary mechanical support and positioning that distributes operational stresses more evenly across the seal assembly. By establishing proper geometric alignment before operation begins, the tabs prevent uneven loading and stress concentrations that would occur with misaligned components, thereby reducing peak stress levels during operation.
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 efficient sealing with reduced heat generation and stress, lowering manufacturing costs and simplifying assembly, while maintaining effective sealing performance across various rotational equipment applications.
Implementation Method 1
a primary hydrostatic seal device with arcuate seal shoes and spring elements
Data Source
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AI summary
An assembly is provided for rotational equipment with an axial centerline 22. This assembly includes a primary seal device 40, a ring structure 44 and a secondary seal device 42. The primary seal device 40 is configured as a hydrostatic non-contact seal device. The primary seal device 40 includes a plurality of seal shoes 54 and a seal base 52. The seal shoes 54 are arranged circumferentially about the axial centerline 22 in an annular array. The seal base 52 circumscribes the annular array of the seal shoes 54. The ring structure 44 is axially engaged with the seal base 52. The secondary seal device 42 is mounted with the ring structure 44. The secondary seal device 42 includes a seal ring body 90 and an alignment tab 104. The seal ring body 90 is configured to substantially seal an annular gap 30 between the ring structure and the seal base 52. The alignment tab 104 projects out from the seal ring body 90 and into an aperture 106 in the ring structure 44. The alignment tab 104 is adapted to substantially rotationally locate and/or fix the secondary seal device 42 to the ring structure 44.