Magnetic Levitation Seal Structure for Compressor Leakage Reduction
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Solution Overview
Problem
The existing sealing systems in magnetic levitating centrifugal compressors suffer from high gas leakage due to a relatively large radial clearance between the seal and the motor shaft, resulting in lower efficiency and poor sealing effectiveness.
Innovation Solution
A sealing system utilizing a combination of magnets and springs to levitate the seal relative to the motor shaft, reducing the radial clearance and minimizing gas leakage, with a design that includes radially or axially magnetizing permanent magnets and anti-rotation pins to maintain concentric alignment and prevent seal rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed labyrinth seal structure with teeth is used between the impeller and motor cavity, then the seal is protected from damage due to collision, but the radial clearance must be large which causes high gas leakage and poor sealing effect
Solution Approach 1:
The patent transforms the fixed seal structure into a dynamic levitating seal structure. The seal is equipped with magnetic levitation bearings that use magnetic fields to levitate the seal relative to the motor shaft, enabling the seal to dynamically adjust its position and maintain a small radial clearance without physical contact, thus achieving both protection from collision damage and reduced gas leakage
Solution Approach 2:
The patent replaces the traditional mechanical contact-based seal protection mechanism with a magnetic field-based levitation system. Instead of relying on physical clearance for protection, the magnetic levitation bearing uses magnetic repulsion and attraction forces to maintain the seal's position, eliminating the need for large radial clearance while still protecting the seal from damage
2Loss of energy
If the radial clearance between the seal and motor shaft is reduced to improve sealing effect, then gas leakage decreases, but the risk of collision damage to the seal increases
Solution Approach 1:
The patent introduces magnetic fields as an intermediary between the seal and the motor shaft. The magnetic levitation bearing generates magnetic fields that act as a mediator to maintain the radial clearance at an optimal small value, preventing direct contact and collision damage while enabling the small clearance needed for effective sealing
Solution Approach 2:
The seal structure is made dynamic through magnetic levitation, allowing it to automatically adjust its position in response to operational conditions. This dynamic capability enables the seal to maintain small radial clearance for effective sealing while the magnetic levitation system continuously adjusts to prevent collision damage
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 solution effectively reduces gas leakage by allowing for a smaller radial clearance between the seal and the motor shaft, enhancing the sealing efficiency and operational performance of the magnetic levitating centrifugal compressor without additional tooling or special designs.
Implementation Method 1
said first magnet and said second magnet form a radial repulsive force in the radial direction of said motor shaft, so that said seal can be levitated relative to (in relation to) said motor shaft
Data Source
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AI summary
A sealing system for a magnetic levitating centrifugal compressor is provided. Said magnetic levitating centrifugal compressor comprises a motor cavity and a motor shaft 100 disposed within said motor cavity. An end of said motor shaft 100 extends out from said motor cavity and is mounted with an impeller. Said sealing system comprises: a seal 120 which is sleeved on the outer side of said motor shaft 100 and is disposed between said impeller and said motor cavity; a first magnet 130 which is fixed at the outer surface of said motor shaft 100; and a second magnet 140 which is fixed at a side of said seal 120 facing said motor shaft 100; wherein said first magnet 130 and said second magnet 140 form a radial repulsive force in the radial direction of said motor shaft 100, so that said seal 120 can be levitated in relation to said motor shaft 100 and move therewith. There is also proposed a magnetic levitating centrifugal compressor provided with said sealing system, and a refrigeration system configured with said magnetic levitating centrifugal compressor.