Labyrinth Seal Vacuum Bore Motor-Fan Liquid Evacuation
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Solution Overview
Problem
Existing motor-fan units face premature failure due to liquid penetration through the rotating shaft, causing bearing degreasing and electrical component damage, as conventional seals are inefficient in evacuating moisture and debris.
Innovation Solution
A labyrinth seal and vacuum bore system is integrated around the rotating shaft to prevent liquid intrusion and evacuate accumulated moisture, utilizing a labyrinth seal with a vacuum bore that generates negative pressure to remove liquids from the evacuation zone.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional seals are used to prevent liquid penetration through the rotating shaft, then liquid prevention is partially achieved, but the seals are inefficient and fail to provide adequate liquid evacuation capability
Solution Approach 1:
The seal is divided into multiple labyrinthine chambers separated by alternating land and groove structures. Liquid must navigate through multiple segmented barriers rather than a single continuous path, significantly reducing penetration effectiveness while maintaining manufacturing feasibility through standardized repeating patterns.
Solution Approach 2:
The seal transitions from a simple radial barrier to a three-dimensional labyrinthine structure with axial and radial components. Liquid must traverse multiple dimensions including axial grooves and radial lands, creating a complex evacuation path that conventional two-dimensional seals cannot provide.
2Reliability
If air seals are used to generate vacuum pressure for liquid evacuation, then some liquid removal is achieved, but the vacuum pressure generated is insufficient for thorough evacuation
Solution Approach 1:
The labyrinthine structure acts as an intermediary mechanism between the liquid intrusion path and the vacuum evacuation system. The multiple chambers and constricted passages amplify the effect of available vacuum pressure by creating pressure differentials across each chamber, enabling thorough evacuation without requiring high-power vacuum generation.
Solution Approach 2:
The seal design changes the pressure distribution parameters throughout the labyrinthine chambers. By creating progressive pressure differentials across multiple chambers with varying land and groove dimensions, the system maximizes liquid evacuation efficiency using moderate vacuum pressure rather than requiring high power input.
3Ease of operation
If a simple shaft aperture is used to allow shaft rotation, then shaft movement is enabled, but liquid and debris can freely penetrate into the motor unit
Solution Approach 1:
The simple continuous aperture is segmented into multiple discrete labyrinthine chambers separated by lands. The shaft can still rotate freely through the centered bore, but liquid penetration is blocked by the segmented structure requiring navigation through multiple barriers rather than a single open passage.
Solution Approach 2:
The labyrinthine chambers with alternating lands and grooves serve as an intermediary barrier between the shaft rotation function and liquid penetration prevention. The structure mediates between these conflicting requirements by allowing radial shaft movement while creating tortuous liquid paths that prevent penetration.
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 prevents liquid from reaching the motor unit's bearings and electrical components, extending the motor-fan unit's operational life by ensuring efficient liquid evacuation and preventing corrosion.
Implementation Method 1
a vacuum bore extending from an outlet port disposed proximate the shaft end to a vacuum port disposed upon an outer surface of the shaft located proximate the evacuation zone, wherein liquid collected within the evacuation zone is discharged through the vacuum bore
Implementation Method 2
a labyrinth seal disposed within the aperture, the labyrinth seal maintaining a seal about the shaft, so as to prevent the intrusion of liquid through the end plate
Data Source
AI summary
A labyrinth seal for a bypass discharge-type motor-fan unit includes a motor unit from which extends a rotating shaft that passes through an aperture in an end plate to drive a fan unit. Disposed within the aperture is a labyrinth seal configured to prevent liquid entrained in a working airflow from entering the motor unit. The rotating shaft also includes a vacuum bore, such that the negative pressure generated by the operation of the fan unit draws any liquid out of an evacuation zone maintained between the motor unit and the end plate. As such, the components of the motor unit are protected from being exposed to the liquid, thereby extending the operating life motor-fan unit.