Labyrinth Shaft Seal Assembly With Floating Stator Clearance Control
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Solution Overview
Problem
Existing shaft seal technologies fail to provide a satisfactory seal when a rotatable shaft is angularly misaligned, often resulting in reduced efficiency and efficacy due to the need for either 'tight' or 'loose' clearance, which complicates alignment and wear issues, especially in product seals where shaft misalignment is common.
Innovation Solution
A shaft seal assembly that incorporates a labyrinth seal with a floating stator and anti-rotation pins, allowing for angular misalignment while maintaining a defined clearance through a combination of o-ring channels and anti-rotation mechanisms, enabling both sealing efficacy and adjustment for operational conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If tight clearance is used to create required pressure differential for sealing, then sealing efficacy is improved, but shaft misalignment tolerance deteriorates
Solution Approach 1:
The patent employs a floating stator that can dynamically adjust its position radially in response to shaft misalignment. The floating stator is supported on bearings allowing it to float and self-align with the rotating shaft, maintaining an optimal sealing clearance dynamically rather than being fixed. This dynamic adjustment capability resolves the contradiction by enabling the seal to adapt to misalignment while preserving sealing effectiveness.
Solution Approach 2:
The invention changes the clearance parameter from a fixed tight clearance to a variable clearance that can adjust based on operating conditions. The floating stator mechanism allows the clearance to increase when misalignment occurs, preventing contact and wear, while maintaining adequate sealing. This parameter change enables the system to tolerate misalignment without sacrificing sealing efficacy.
2Adaptability or versatility
If loose clearance is used to accommodate shaft misalignment, then shaft misalignment tolerance is improved, but sealing efficacy deteriorates
Solution Approach 1:
The floating stator creates a dynamic clearance system that is tight when needed for sealing and loose when needed for misalignment accommodation. The stator floats on bearings and can move radially to maintain optimal clearance, providing tight sealing under normal conditions and allowing increased clearance when misalignment occurs.
Solution Approach 2:
The floating stator self-adjusts its position based on the shaft position and operating conditions. It automatically maintains the optimal balance between tight sealing and loose misalignment tolerance without external control, serving itself to resolve the contradiction between these two opposing requirements.
3Reliability
If contact seals are used to maintain tight clearance, then sealing efficacy is improved, but wear increases due to shaft misalignment
Solution Approach 1:
The patent extracts the contact element from the sealing system by using a floating stator with radial clearance instead of contact seals. The floating stator is supported on bearings that prevent contact with the shaft, eliminating the wear mechanism while maintaining sealing through the controlled clearance and fluid pressure differential.
Solution Approach 2:
The floating stator acts as an intermediary between the shaft and the stationary seal housing. It maintains the sealing function through controlled clearance while the bearing support system mediates the misalignment forces, preventing direct contact and wear between sealing surfaces.
4Duration of action of moving object
If labyrinth seals are used to reduce contact wear, then wear resistance is improved, but sealing efficacy deteriorates due to loose clearance requirement
Solution Approach 1:
The patent merges the advantages of contact seals (tight sealing) with the advantages of non-contact seals (wear resistance) by using a floating stator with controlled radial clearance supported on bearings. This hybrid approach combines the tight clearance needed for effective sealing with the bearing-supported non-contact operation that provides wear resistance.
Data Source
AI summary
A shaft seal assembly comprises a stator configured to engage a housing and a rotor positioned within the stator. The stator may include a main body, a stator inward radial projection extending radially inward from the stator main body, and a collection groove adjacent the stator inward radial projection. The rotor may include a rotor main body and a rotor axial projection extending from the rotor main body. The rotor axial projection may be positioned adjacent a distal end of the stator inward radial projection.