Intershaft Seal Ring Separation for Low-Heat Noncontact Sealing
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Solution Overview
Problem
Existing seal systems in rotating machinery face challenges in maintaining effective sealing while minimizing contact-related heat generation and wear, especially under extreme conditions and high operational bandwidths, which can lead to reduced service life and operational limitations.
Innovation Solution
A noncontacting intershaft seal system is developed, featuring a hollow outer shaft with an inner shaft and axially spaced end plates that include force generating mechanisms, such as magnetic or hydrodynamic systems, to maintain separation between a split ring and the end plates, reducing contact and heat generation. The split ring is configured to expand and engage with the outer shaft, using low friction materials and magnetic repulsion to prevent contact during axial excursions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If contact seals are used to maintain sealing between shafts, then sealing effectiveness is improved, but heat generation and wear increase
Solution Approach 1:
The patent replaces traditional mechanical contact seals with a magnetic field-based noncontacting seal system. Magnets mounted on the inner shaft interact with corresponding magnets on the outer shaft to create magnetic pressure that maintains sealing without physical contact, eliminating friction-induced heat and wear while preserving sealing effectiveness
Solution Approach 2:
The patent changes the fundamental operating parameter from mechanical contact to magnetic field interaction. By using magnetic pressure instead of mechanical contact pressure, the system achieves sealing without the harmful effects of friction, heat generation, and wear that characterize traditional contact seals
2Productivity
If higher operating speeds and pressures are achieved, then productivity is improved, but contact-related wear and heat generation worsen
Solution Approach 1:
By replacing mechanical contact with magnetic field interaction, the system enables higher operating speeds and pressures without the limiting factors of friction, heat generation, and wear that would otherwise reduce service life and constrain operational capabilities
3Object-generated harmful factors
If noncontacting seal system is used, then heat generation and wear are reduced, but sealing effectiveness under differential pressure may worsen
Solution Approach 1:
The patent uses magnetic pressure as the sealing mechanism, where the magnetic field strength can be designed to provide sufficient normal force to maintain sealing under differential pressure conditions without requiring mechanical contact, thus eliminating heat and wear while preserving sealing reliability
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 solution effectively reduces heat generation and wear, allowing for higher operating speeds and pressures, thereby extending the service life of machinery by maintaining noncontact operation and minimizing parasitic losses, even under extreme conditions.
Implementation Method 1
The end plates include force generating elements that generate desirable forces to separate the ring from the end plates
Implementation Method 2
A split ring is disposed in the gland opening and operates to expand during rotation to engage and rotate with the outer shaft
Implementation Method 3
The split ring comprises a low friction material, including in areas disposed between the series of magnets and the end plates
Data Source
AI summary
A noncontacting intershaft seal system includes force generating mechanisms to reduce contact related effects. A sealing system includes an outer shaft that has a hollow interior. An inner shaft extends through the hollow interior of the outer shaft. Spaced apart end plates encircle and rotate with the inner shaft. A gland opening is defined between the inner and outer shafts and between the end plates. A ring is disposed in the gland opening. The end plates and/or the ring include force generating elements that generate force to separate the ring from the end plates, reducing contact related heat generation and wear.