Dry Gas Thrust Bearing With Double Spring Biasing
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Solution Overview
Problem
Conventional liquid-lubricated thrust bearings are not suitable for applications where oil lubrication is not feasible, such as in high-speed, high-pressure rotating equipment like turbines and compressors, as they fail to effectively manage thrust loads without risking component damage from axial displacement.
Innovation Solution
A dry gas thrust bearing with a double symmetrical rotating arrangement and a double spring biasing system that generates a hydrodynamic dry gas film between rotor and stator bearing faces, allowing for flexible mounting and sufficient film stiffness to counterbalance thrust loads, with a transition from low to high spring force as thrust loads increase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If liquid lubrication is used in thrust bearings, then the bearing can support thrust loads, but the bearing cannot be used in applications where oil lubrication is not feasible (high-speed, high-pressure rotating equipment)
Solution Approach 1:
The patent replaces liquid lubrication with gas lubrication, using compressed gas (typically air) to form a lubricating film between bearing surfaces. The bearing includes gas supply channels that deliver pressurized gas to the bearing interface, creating a hydrodynamic gas film that supports thrust loads without requiring oil lubrication, thereby enabling use in high-speed, high-pressure rotating equipment where liquid lubrication is not feasible.
Solution Approach 2:
The invention changes the physical state of the lubricant from liquid to gas phase. By using gas instead of liquid lubrication, the bearing becomes suitable for applications where liquid lubricants would evaporate, carbonize, or fail under high-speed and high-pressure conditions. The gas lubrication system maintains adequate film thickness and load-bearing capacity through controlled gas pressure and flow parameters.
2Adaptability or versatility
If a dry gas film is used to support thrust loads, then the bearing can operate without oil lubrication, but the bearing faces may contact and cause damage under varying thrust conditions
Solution Approach 1:
The patent incorporates spring elements positioned between the bearing components that act as mechanical cushions. These springs are pre-loaded to maintain a minimum separation distance between bearing surfaces, preventing direct metal-to-metal contact during startup, shutdown, or transient conditions when the gas film may be insufficient. The spring cushioning absorbs shock loads and protects the precision bearing faces from damage.
Solution Approach 2:
The bearing employs composite construction combining rigid bearing surfaces with flexible spring elements. The composite structure integrates the load-bearing gas film mechanism with the protective spring cushioning system, creating a hybrid thrust bearing that leverages both hydrodynamic gas lubrication and elastic deformation to prevent component contact under varying operational conditions.
3Reliability
If spring biasing is used to maintain bearing clearance, then the bearing can accommodate thrust loads, but the spring force may be insufficient during start-up and excessive during high-speed operation
Solution Approach 1:
The spring biasing system is divided into multiple independent spring elements distributed around the bearing perimeter. Each spring segment independently maintains local clearance and accommodates thrust loads. This segmentation allows the total spring force to be distributed, providing adequate pre-load during startup while preventing excessive force concentration during high-speed operation. The segmented springs can deflect independently to accommodate varying load conditions.
Solution Approach 2:
The spring biasing system is designed to be dynamically responsive to operating conditions. During startup, when thrust loads are low, the springs maintain adequate pre-load to ensure bearing clearance and prevent contact. During high-speed operation, when hydrodynamic gas pressure increases, the springs compress further, automatically reducing the net force on the bearing faces. This dynamic behavior allows the same spring system to provide appropriate force magnitude across varying operational regimes.
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 dry gas thrust bearing effectively supports thrust loads across varying operational conditions, preventing component contact and damage, while maintaining a light pre-load during start-up and engaging a higher spring force as thrust loads rise, ensuring reliable operation even at high speeds and pressures.
Implementation Method 1
biasing means preferably formed as a spring package which biases the stators towards the rotor bearing faces
Implementation Method 2
Some or possibly all of these bearing faces include hydrodymanic lift features which hydrodynamically generate a dry gas fluid film between the rotor and stator bearing faces during relative rotation thereof
Data Source
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AI summary
and more particularly, this thrust bearing is designed to support compressor/turbine thrust loads in an improved arrangement which does not require oil lubrication and which is designed to support necessary shaft thrust loading by the utilization of a dry gas film. The bearing includes a shaft rotor 23 between two axially movable stators 39 and relies on a dry gas film to separate the rotor 23 and stators 39. The stators 39 are axially loaded by a double spring package 64 arranged in series wherein a lightly loaded spring engages the stator 39 during zero thrust applications, and as the shaft 14 begins to rotate and encounter axial thrust, a heavier stiffer spring, greater than the thrust load, quickly engages.