Electromagnetic Gas Bearing Support for Dry Friction Reduction
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Solution Overview
Problem
The dry friction between the foil and motor shaft during the start-up/shut-down stage of gas bearings in centrifugal compressors affects stability and limits their widespread application.
Innovation Solution
A gas bearing with an electromagnetic structure that provides a vertically upward electromagnetic force to counteract the gravity of the motor shaft, reducing dry friction and improving stability during these stages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gas bearing is used for oil-free lubrication in centrifugal compressors, then operating efficiency and reliability are improved, but dry friction during start-up/shut-down stage worsens stability
Solution Approach 1:
The patent replaces the purely mechanical gas bearing support system with an electromagnetic support system during start-up and shut-down stages. The electromagnetic bearing generates lifting force to counteract gravity on the motor shaft, eliminating the need for mechanical contact between the foil and motor shaft during these critical phases. This substitution of mechanical support with electromagnetic support resolves the dry friction problem while maintaining reliability.
Solution Approach 2:
The patent applies preliminary action by activating the electromagnetic bearing before the gas bearing becomes operational during start-up, and continuing its operation during shut-down. This ensures that the motor shaft is supported electromagnetically during the periods when gas film formation is insufficient, preventing dry friction before it occurs and maintaining stability throughout the transition phases.
2Duration of action of stationary object
If friction-resistant coating is applied on the foil to reduce dry friction, then wear during start-up/shut-down is reduced, but device complexity increases
Solution Approach 1:
The patent eliminates the need for complex friction-resistant coatings by replacing mechanical contact with electromagnetic support during the most demanding phases (start-up and shut-down). This substitution removes the requirement for specialized coating materials and application processes, thereby extending foil service life without increasing device complexity.
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
Reduces wear and prolongs the service life of the gas bearing, enhancing system stability and expanding its application range.
Implementation Method 1
The gas bearing comprises: a bearing housing, sleeved on an outer side of the motor shaft and fixed on the housing of the centrifugal compressor; an electromagnetic stator, fixed in or near the middle of the top of the bearing housing, and wound with a coil that can be powered; an electromagnetic rotor, fixed on an outer surface of the motor shaft and arranged circumferentially around the motor shaft
Data Source
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AI summary
The present invention relates to a gas bearing (120) for a centrifugal compressor, comprising a housing and a motor shaft (110) located within the housing. The gas bearing comprises: a bearing housing (121), sleeved on an outer side of the motor shaft (110) and fixed on the housing of the centrifugal compressor; an electromagnetic stator (122), fixed in or near the middle of the top of the bearing housing (121), and wound with a coil that can be powered; an electromagnetic rotor (123), fixed on an outer surface of the motor shaft (110) and arranged circumferentially around the motor shaft; and a foil (124), located between the bearing housing (121) and the motor shaft (110), and attached with a friction-resistant coating. The present invention further proposes a centrifugal compressor configured with the gas bearing, and a refrigeration system equipped with the centrifugal compressor.