Secondary Seal Plate Sliding Surface for Non-Contact Seal Heat Reduction
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Solution Overview
Problem
Existing non-contact seals for rotational equipment do not adequately address the issue of secondary sealing characteristics, leading to inefficiencies and increased costs due to heat generation and the need for high-temperature materials.
Innovation Solution
The proposed solution involves a non-contact seal assembly for rotational equipment that includes a primary seal device with seal shoes and spring elements, and secondary seal devices that are free-floating and torsionally flexible, allowing them to maintain sealing engagement despite axial misalignment and thermal expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a contact seal with a seal element is used to seal the gap, then sealing effectiveness is improved, but heat generation increases and efficiency decreases
Solution Approach 1:
The patent replaces the traditional mechanical contact seal system with a non-contact magnetic seal system. The magnetic field exerts force on the seal element without physical contact, eliminating friction and heat generation while maintaining sealing effectiveness. The seal element is suspended in the gap by magnetic forces, allowing it to seal the interface between rotor and stator without rubbing against the opposing surface.
2Strength
If high-temperature materials are used to accommodate high temperatures and stresses, then component durability is improved, but manufacturing and servicing costs increase significantly
Solution Approach 1:
By replacing the contact-based mechanical seal with a non-contact magnetic seal, the system eliminates the high-temperature and high-stress conditions that would require expensive specialty materials. The magnetic field transmits force without direct contact, preventing the thermal and mechanical loading that necessitates costly high-temperature alloys and complex manufacturing processes.
3Loss of energy
If a non-contact seal is used to reduce heat generation, then energy efficiency is improved, but secondary sealing characteristics are insufficient
Solution Approach 1:
The patent applies local quality by providing different sealing mechanisms at different locations. The magnetic seal element provides primary non-contact sealing in the radial direction, while additional seal elements or structures provide secondary sealing in the axial direction. This localized differentiation of sealing functions ensures both heat reduction through non-contact operation and adequate secondary sealing characteristics.
Solution Approach 2:
The sealing system is segmented into multiple functional zones: the primary magnetic seal element handles radial sealing, while separate axial seal structures handle end-sealing. This segmentation allows each component to be optimized for its specific function, with the primary seal minimizing heat generation and the secondary seals providing adequate leakage prevention.
Data Source
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AI summary
A rotational equipment assembly (28) includes a plurality of seal shoes (54), a seal base (52), a plurality of spring elements (56) and a secondary seal assembly (44). The seal shoes (54) are arranged circumferentially around an axial centerline (22) and include a first seal shoe (54). The first seal shoe (54) includes a first seal shoe base (74) and a first seal shoe rib (78) that projects axially out from the first seal shoe base (74) to an axial distal end (112) of the first seal shoe rib (78). The seal base (52) extends circumferentially around the axial centerline (22). The spring elements (56) include a first spring element (56) that connects and extends between the first seal shoe (54) and the seal base (52). The secondary seal assembly (44) is configured to seal a gap between the seal base (52) and the seal shoes (54). The secondary seal assembly (44) includes a free floating seal plate (40) that axially contacts and is configured to slide radially along the first seal shoe rib (78).