Dual-Material Hydrostatic Seal Assembly for Heat and Vibration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Rotational equipment's contact seals generate excessive heat and internal stresses, leading to increased manufacturing and servicing costs, as well as weight, due to the need for high-temperature materials to accommodate these conditions.
Innovation Solution
A dual-material hydrostatic non-contact seal assembly is used, where a nickel alloy is employed for the seal base and a lighter, lower-density material like cobalt alloy or aluminum for the seal shoes, joined together and heat-treated for optimal performance, to reduce weight and enhance vibrational response.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If contact seals 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 that uses fluid pressure to maintain the sealing gap, eliminating direct mechanical contact and the associated frictional heat generation while maintaining sealing effectiveness
Solution Approach 2:
The patent employs hydrostatic principles by using fluid pressure to generate a separating force between the seal surfaces, creating a non-contact sealing mechanism that avoids the heat generation problems of contact seals while maintaining reliable sealing
2Reliability
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:
The patent eliminates the need for high-temperature materials by replacing the contact seal system with a non-contact hydrostatic seal system, thereby removing the thermal stress problem that necessitated expensive specialty materials while maintaining component durability
Solution Approach 2:
The patent changes the operating parameters of the seal system by eliminating direct contact and reducing friction, which dramatically lowers the temperature and stress levels, allowing the use of standard materials instead of expensive high-temperature specialty materials
3Strength
If high-temperature materials are used to accommodate high temperatures and stresses, then component strength is improved, but the mass of the rotational equipment increases significantly
Solution Approach 1:
The patent replaces the contact seal system with a hydrostatic non-contact seal system, eliminating the need for heavy high-temperature materials while maintaining component strength through reduced thermal and mechanical stresses
Solution Approach 2:
The patent changes the thermal and mechanical parameters of the seal system by eliminating contact friction, which reduces the required material strength and allows the use of lighter materials while maintaining adequate component strength
4Weight of moving object
If seal mass is reduced to decrease overall engine weight, then weight is improved, but vibrational response optimization becomes more difficult
Solution Approach 1:
The patent uses composite construction with a lightweight seal shoe material combined with a dense anchor ring material, achieving reduced overall mass while maintaining adequate vibrational characteristics through the combined properties of the two materials
Solution Approach 2:
The patent applies different material properties to different parts of the seal assembly - using lightweight material where mass reduction is critical (seal shoe) and denser material where structural stability and vibrational characteristics are important (anchor ring), optimizing both weight and vibrational response
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
This configuration decreases the seal's mass, increases its natural frequency, and maintains stress levels within acceptable limits, thereby improving the seal's efficiency and reducing the risk of high cycle fatigue and leakage while maintaining optimal performance.
Implementation Method 1
hydrostatic non-contact seal assembly...configured to substantially seal an annular gap between the stator structure and the rotor structure
Implementation Method 2
a plurality of spring elements arranged circumferentially about the axial centerline...radially between the seal shoes and the seal base
Data Source
Figure 1
Figure 2
Figure 3
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) including a first seal shoe (54) extending axially along the centerline (22) between a first shoe end (70) and a second shoe end (72), a seal base (52) circumscribing the annular array of the seal shoes (54), and 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 seal base (52) and the plurality of spring elements (56) are formed of a first material and the plurality of seal shoes (54) are formed of a second material, where the first and second materials are joined together and the second material has a density lower than the first material.