Touchdown Bearing Flushing to Prevent Debris Buildup in Compressors
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Solution Overview
Problem
The buildup of debris in touchdown bearings within compressors can lead to seizing, potentially causing damage to the rotating shaft, as existing methods do not effectively prevent or mitigate this issue.
Innovation Solution
A method involving the continuous injection of a working fluid, such as refrigerant, through a supply line into the touchdown bearing when the compressor is operational, using magnetic bearings to levitate the shaft and touchdown bearings to support it during shutdown, which helps to flush out debris by rotating the bearing between races.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ball bearings are used as touchdown bearings, then smooth rotation and shaft protection are provided, but debris accumulates in the clearance between the ball and races causing seizing
Solution Approach 1:
The patent extracts the harmful debris from the bearing clearance by introducing a flushing mechanism. A supply line delivers working fluid to the touchdown bearing, and a drain line removes the contaminated fluid, effectively extracting debris from the clearance between the ball and races.
Solution Approach 2:
The patent uses hydraulic flushing by injecting working fluid through a supply line into the touchdown bearing clearance. The fluid flow carries debris away from the bearing, and the contaminated fluid is drained through a drain line, applying pneumatic and hydraulic principles to prevent debris accumulation.
2Reliability
If continuous flushing is implemented, then debris buildup is prevented, but system complexity increases
Solution Approach 1:
The working fluid serves multiple functions: it acts as a lubricant for the magnetic bearing during operation, a flushing medium for the touchdown bearing during shutdown, and a carrier for debris removal. This multi-functionality reduces the need for separate dedicated flushing systems.
Solution Approach 2:
The system uses its own working fluid cycle to flush the touchdown bearing, rather than requiring an external dedicated flushing system. The fluid is recirculated through the system, and the flushing action is integrated into the normal operation cycles of the vapor compression system.
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 method effectively prevents or mitigates the buildup of debris within the touchdown bearings, reducing the risk of seizing and ensuring smooth operation by injecting the working fluid at a sufficient velocity to dislodge any debris, thus maintaining the integrity of the rotating shaft.
Implementation Method 1
levitating the rotating shaft using a magnetic bearing disposed adjacent to the electric motor
Implementation Method 2
injecting the working fluid at a velocity of at least five (5) ft. /sec (1.5 m/s)... Injecting the working fluid mitigates a buildup of a debris between the touchdown bearing and the races
Data Source
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AI summary
A compressor 100 with a touchdown bearing 120 and a supply line 150 for injecting a working fluid toward the touchdown bearing, and a vapor compression system 800 incorporating the same are provided. The supply line injects working fluid approximately continuously when the compressor is operational. The compressor includes a magnetic bearing 110 for levitating the rotating shaft 140 when the compressor is operational. The touchdown bearing is used to support the rotating shaft when the compressor is shutdown. The touchdown bearing may be disposed, at least partially, between a pair of races 123. The injecting of the working fluid may cause the touchdown bearing to rotate between the races. The injecting of the working fluid may help mitigate a buildup of a debris between the touchdown bearing and the races.