Hydrostatic Non-Contact Seal Shoes With Weight-Reduction Pockets
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Solution Overview
Problem
Rotational equipment seal assemblies with contact seals generate excessive heat and internal stresses, leading to increased manufacturing and servicing costs, as well as elevated mass due to the use of high-temperature materials, which negatively impacts efficiency and vibrational response.
Innovation Solution
The implementation of a non-contact hydrostatic seal assembly with weight reduction pockets in the seal shoes, formed from nickel or cobalt alloys, which reduces the mass of the seal components without compromising structural strength or increasing stress levels in the spring elements, thereby enhancing the natural frequency and modal response of the seal system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If contact seals with seal elements are used to seal gaps between rotors and stators, then sealing effectiveness is improved, but heat generation increases and efficiency decreases
Solution Approach 1:
The patent replaces the mechanical contact seal system with a hydrostatic non-contact seal system. Instead of relying on physical contact between seal elements and seal lands, the invention uses fluid pressure to maintain a separation between the rotor and stator, eliminating the mechanical contact that generates heat and energy loss while preserving sealing effectiveness through the hydrostatic film.
2Reliability
If high-temperature materials are used to accommodate high temperatures and internal stresses, then component durability is improved, but manufacturing and servicing costs increase
Solution Approach 1:
By replacing the contact seal mechanism with a hydrostatic non-contact system, the patent eliminates the high-temperature conditions that would require expensive specialty materials. The non-contact design prevents the frictional heating that necessitates high-temperature material usage, thereby reducing manufacturing and servicing costs while maintaining component durability.
3Reliability
If high-temperature materials are used to withstand high temperatures and stresses, then component reliability is improved, but the mass of rotational equipment increases
Solution Approach 1:
The patent substitutes the contact seal system with a hydrostatic non-contact system, which eliminates the need for heavy high-temperature materials. By preventing heat generation through non-contact operation, the invention allows the use of lighter materials that do not require high-temperature resistance, thereby reducing the overall mass of the rotational equipment while maintaining reliability.
4Weight of moving object
If seal mass is reduced to decrease overall engine weight, then equipment efficiency is improved, but structural strength of seal components may be compromised
Solution Approach 1:
The patent divides the seal shoe structure into multiple segments by incorporating pockets within the seal shoe body. This segmentation allows strategic removal of material to reduce mass while maintaining the overall structural integrity. The pockets are positioned to eliminate unnecessary mass without compromising the load-bearing pathways, enabling weight reduction while preserving structural strength.
Solution Approach 2:
The patent applies local quality by creating pockets in specific regions of the seal shoe where material can be removed without affecting critical structural areas. The pockets are strategically located to reduce mass in non-critical zones while maintaining adequate thickness and strength in load-bearing regions, achieving weight reduction without compromising overall structural strength.
5Speed
If weight reduction pockets are added to seal shoes, then natural frequency and vibrational response are enhanced, but device complexity increases
Solution Approach 1:
The patent incorporates pockets within the seal shoe structure as a segmented approach to modify the mass distribution. These pockets create a more favorable mass moment of inertia that enhances natural frequency and vibrational response. The segmentation is achieved through relatively simple geometric modifications rather than complex additional components, minimizing the increase in device complexity while achieving the desired dynamic performance improvement.
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 weight reduction pockets in the seal shoes enhance the natural frequency and vibrational response of the seal system, reducing the overall mass and heat generation, while maintaining structural integrity and minimizing stress on the spring elements, thus optimizing the seal's performance and efficiency.
Implementation Method 1
A plurality of spring elements are arranged radially between the seal shoes and the seal base
Implementation Method 2
hydrostatic non-contact seals with a weight reduction pocket
Data Source
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AI summary
A non-contact seal assembly (28) is provided. The non-contact seal assembly (28) includes a plurality of seal shoes (54) arranged about a centerline (22) in an annular array, the seal shoes (54) include a first seal shoe (54) extending axially along the centerline (22) between a first shoe end (70) and a second shoe end (72). The non-contact seal assembly (28) may comprise a seal base (52) circumscribing the annular array of the seal shoes (54). The non-contact seal assembly (28) may further comprise a plurality of spring elements (56), each of the spring elements (56) radially between and connecting a respective one of the seal shoes (54) with the seal base (52), where the plurality of seal shoes (54) each includes a weight reduction pocket (81) formed in a circumferential region of the seal shoe (54).