Porous Air Bearing Seal for Stable Non-Contact Pressure Gaps
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional sealing and bearing systems in turbo equipment face issues such as wear, leakage, noise, and inefficiencies due to contact-based seals, and non-contact seals often fail to effectively manage pressure differentials, leading to significant maintenance costs and operational challenges.
Innovation Solution
The implementation of porous externally pressurized gas bearings that combine sealing and bearing functions, utilizing a porous media to distribute hydrostatic pressure and maintain a non-contact air bearing gap, which operates independently of relative motion and can handle extreme temperatures, reducing wear and pressure between contacting faces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If contact-based seals (lip seals, brush seals) are used, then sealing function is provided, but wear and friction occur leading to maintenance costs and heat generation
Solution Approach 1:
The patent replaces contact-based mechanical seals with a non-contact magnetic bearing system. The magnetic bearing uses magnetic fields to levitate and support the rotor, eliminating mechanical contact between rotating and stationary components. This substitution removes wear and friction entirely while maintaining sealing functionality through the magnetic field barrier.
Solution Approach 2:
The patent introduces a gas film (typically air or inert gas) between the rotor and stator components. This gas film acts as both a lubricant and seal, preventing direct contact while allowing the rotor to spin. The gas pressure is controlled to maintain the film thickness, providing both bearing support and sealing functions without mechanical contact.
2Object-generated harmful factors
If non-contact seals (labyrinth seals, gas seals) are used, then wear is reduced, but pressure differentials cause significant leakage
Solution Approach 1:
The magnetic bearing system divides the sealing function into multiple magnetic pole segments around the rotor. Each pole pair creates a localized magnetic barrier that collectively forms a complete sealing envelope. This segmentation allows the system to handle pressure differentials more effectively by distributing the sealing effort across multiple zones rather than relying on a single continuous barrier.
Solution Approach 2:
The patent adjusts magnetic field strength and gas pressure parameters dynamically to optimize sealing performance. By increasing magnetic field intensity or adjusting gas film pressure in response to detected leakage or load changes, the system maintains effective sealing across varying operating conditions without increasing mechanical contact.
3Force
If conventional oil bearings are used, then load support is provided, but oil leakage and environmental concerns arise
Solution Approach 1:
The patent replaces oil-lubricated mechanical bearings with a magnetic bearing system that uses electromagnetic fields for load support. The magnetic attraction and repulsion forces between rotor and stator components provide bearing support without requiring any lubricant, eliminating oil leakage risks and environmental concerns entirely.
Solution Approach 2:
The system uses a gas film (air or inert gas) instead of liquid oil to support the rotor load. The gas pressure and viscosity are optimized to provide adequate load-bearing capacity while being environmentally benign. This pneumatic approach replaces the hydraulic oil film with a clean gas alternative.
4Reliability
If mechanical seals are used to prevent bearing oil mixing with process fluid, then separation is achieved, but complexity and maintenance increase
Solution Approach 1:
The magnetic bearing system performs multiple functions simultaneously: it provides load support, prevents fluid mixing, and acts as a seal all in one component assembly. The magnetic field and gas film serve both bearing and sealing purposes, eliminating the need for separate mechanical seals and reducing overall system complexity.
Solution Approach 2:
The patent merges the bearing and sealing functions into a single integrated magnetic bearing assembly. The magnetic field barrier and gas film provide both mechanical support and fluid separation, combining what were traditionally separate functions into one unified system that reduces complexity and maintenance requirements.
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 enhances rotordynamic stability, reduces maintenance and energy consumption, eliminates dry-running issues, and provides an environmentally friendly alternative by minimizing oil usage, while allowing for higher speed capabilities and more efficient operation.
Implementation Method 1
porous media to distribute hydrostatic pressure
Implementation Method 2
maintain a non-contact air bearing gap
Data Source
AI summary
In order to effect a seal a porous material which comprises one side of two opposing surfaces is used to restrict and evenly distribute externally pressurized gas, liquid, steam, etc. between the two surfaces, exerting a force which is opposite the forces from pressure differences or springs trying to close the two faces together and so may create a non-contact seal that is more stable and reliable than hydrodynamic seals currently in use. A non-contact bearing is also disclosed having opposing surfaces with relative motion and one surface issuing higher than ambient pressure through a porous restriction, wherein the porous restriction is part of a monolithic porous body, or a porous layer, attached to lands containing a labyrinth, the porous restriction and lands configured to not distort more than 10% of a gap created from differential pressure between each side of the porous restriction.