Labyrinth Seal Structure for Contaminant Exclusion and Lubricant Return
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Solution Overview
Problem
Existing shaft-sealing technologies, such as rubber lip seals and clearance labyrinth seals, fail to effectively prevent lubricant leakage and contamination entry in rotating equipment under extreme conditions, leading to bearing damage and maintenance challenges in industrial settings.
Innovation Solution
A labyrinth seal design featuring radially-outermost annular interfaces, elastomeric seals, and exclusion chambers that direct contaminants inwardly and outwardly, along with a contact avoidance interface and lubricant collecting grooves, enhances sealing performance by preventing contaminant entry and ensuring lubricant return to the sump.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If rubber lip seals or O-ring shaft seals are used to protect bearing environment, then sealing function is provided, but they wear out quickly and fail, and permit excessive moisture and contaminants to migrate into the lubricant reservoir
Solution Approach 1:
The seal is divided into multiple independent elastomeric seal elements (first, second, and third seal elements) positioned at different locations along the shaft. Each seal element provides a separate sealing barrier, so if one fails, others continue to protect. This segmentation improves reliability while maintaining protection against contaminant migration.
Solution Approach 2:
The patent changes from rigid or semi-rigid seal materials to elastomeric materials that can deform and adapt to shaft variations. The elastomeric seals can accommodate thermal expansion, shaft runout, and wear while maintaining sealing effectiveness, thus improving durability without compromising contaminant protection.
2Reliability
If clearance labyrinth seals are used to protect bearing environment, then they provide non-contact sealing, but they fail to effectively prevent lubricant leakage and contamination entry under extreme conditions
Solution Approach 1:
The patent combines the non-contact labyrinth seal structure with multiple elastomeric seal elements in a hybrid configuration. The labyrinth passages provide the primary sealing barrier without contact, while the elastomeric seals provide secondary protection at critical locations. This merging achieves effective sealing under extreme conditions without excessive complexity.
Solution Approach 2:
The elastomeric seal elements act as intermediaries between the non-contact labyrinth structure and the shaft surface. They fill gaps and irregularities that pure clearance seals cannot address, enhancing sealing effectiveness while maintaining the non-contact advantage of labyrinth seals.
3Object-affected harmful factors
If elastomeric seals are positioned to contact the rotor surface for sealing, then sealing performance improves, but wear occurs at the contact interface reducing seal life
Solution Approach 1:
The elastomeric seals are positioned only at specific critical locations where contaminant ingress is most likely, rather than along the entire shaft length. The first seal element is at the forward end, the second at the rearward end, and the third at an intermediate location. This localized approach provides necessary sealing while minimizing total contact area and wear.
Solution Approach 2:
The elastomeric seals are designed to be compliant and adaptable, changing their contact characteristics dynamically based on operating conditions such as shaft rotation, thermal expansion, and load variations. This dynamic behavior allows effective sealing during operation while reducing concentrated wear at any single point.
4Object-affected harmful factors
If multiple seal elements are added to improve sealing performance, then contaminant protection improves, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The elastomeric seal elements are designed with universal features that allow them to be manufactured using similar processes and installed using comparable methods. Each seal element serves multiple functions: sealing, compensating for shaft variations, and guiding contaminant flow. This multi-functionality reduces the need for specialized components and simplifies manufacturing.
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 improved labyrinth seal effectively expels contaminants and maintains lubricant integrity, reducing wear and maintenance needs in harsh industrial environments by promoting contaminant expulsion and efficient lubricant circulation.
Implementation Method 1
one or more annular elastomeric seals disposed between the confronting surfaces of the stator and rotor
Implementation Method 2
The entrance into and pathway along the interface is directed radially inwardly to promote expulsion of contaminant that encroaches into the interface during dynamic operation of the seal
Implementation Method 3
an interface pattern between the confronting surfaces of the stator and rotor that define two radially-disposed exclusion chambers, including a radially-outside exclusion chamber and a radially-inside exclusion chamber
Implementation Method 4
a lubricant collecting groove having a tapered surface that improves the flow of lubricant through a drain in the bottom of the stator, back to the lubrication sump
Data Source
AI summary
A labyrinth seal including a stator and a non-contacting rotor, and annular elastomeric seals. The confronting surfaces of the stator and rotor define at least one interface passage, including a radially-outermost annular interface passage between an annular, outermost, radially-extending projection of the stator and an annular rearwardly-extending distal projection of the rotor that overlaps the radially-extending projection of the stator, the radially-outermost annular interface passage tapering outwardly and rearwardly at an acute angle relative to an axial reference line. The annular elastomeric seals are stationary with the stator during dynamic operation of the rotor, and are not contacted by a surface of the rotor during dynamic operation. The interface can also have two radially-disposed exclusion chambers, the outer exclusion chamber being defined in part by a radially-inboard projection of the rotor. The stator can have a projection providing a contact avoidance interface position inboard of at least two contaminant-excluding interfaces.