Labyrinth Seal Recess Projections Axial Tolerance

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Solution Overview

Problem

Conventional labyrinth seals in fluid machines are complex to manufacture, require precise mounting, and are fragile, making them unsuitable for small and compact designs where they are needed most, due to their intricate shapes and tight tolerances.

Innovation Solution

A simplified labyrinth seal design with stationary and rotary steps featuring recesses and projections of equal axial width, allowing for larger manufacturing tolerances and easier assembly, which reduces manufacturing costs and enhances robustness and efficiency, particularly in compact fluid machines.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If conventional labyrinth seals with complicated shapes are used, then fluid leakage is reduced, but manufacturing complexity and mounting precision requirements increase

Engineering Contradiction:

Improvefluid leakageVSAvoidlabyrinth seal complexity

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The labyrinth seal is divided into multiple discrete steps along the axial direction, with each step having a simplified geometry consisting of basic radial and axial walls. This segmentation allows the complex sealing function to be achieved through multiple simple structures rather than one complex structure, reducing manufacturing difficulty while maintaining leakage control

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention introduces recesses at specific locations (radial walls of stationary steps and axial walls of rotary steps) to create localized flow resistance zones. This local modification approach simplifies the overall geometry while strategically placing complexity only where needed for leakage control, rather than making the entire seal complex

Inventive Principle:

Principle #3Local quality

2Loss of energy

If conventional labyrinth seals with intricate shapes are used, then fluid leakage is minimized, but manufacturing ease and robustness decrease

Engineering Contradiction:

Improvefluid leakageVSAvoidlabyrinth seal manufacturing

Core Design Contradiction:

Loss of energyVSEase of manufacture

Solution Approach 1:

The seal structure is segmented into standardizable steps with uniform geometric features (radial walls, axial walls, and recesses). This segmentation enables modular manufacturing processes and simplifies tooling requirements, making production easier while achieving the same leakage control function

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of creating complex protruding features to control flow, the invention uses recesses (negative space) to achieve the same effect. This inversion simplifies manufacturing by using material removal rather than complex material formation, and creates more robust structures that are easier to manufacture

Inventive Principle:

Principle #13The other way round (Inversion)

3Loss of energy

If conventional labyrinth seals are used, then fluid leakage is controlled, but axial orientation precision and relative axial displacement tolerance decrease

Engineering Contradiction:

Improvefluid leakageVSAvoidaxial orientation precision

Core Design Contradiction:

Loss of energyVSManufacturing precision

Solution Approach 1:

The labyrinth seal design accommodates dynamic axial displacement between rotating and stationary members through its stepped structure with recesses. The seal maintains effective leakage control across a range of axial positions rather than requiring a single precise position, making the system more tolerant of manufacturing variations and operational movements

Inventive Principle:

Principle #15Dynamics

4Loss of energy

If conventional labyrinth seals are used, then fluid leakage is reduced, but adaptability to small and compact fluid machines decreases

Engineering Contradiction:

Improvefluid leakageVSAvoidadaptability to compact designs

Core Design Contradiction:

Loss of energyVSAdaptability or versatility

Solution Approach 1:

The segmented step structure can be scaled to different sizes and configurations suitable for compact fluid machines. Each step can be made smaller while maintaining the functional pattern, allowing the seal to adapt to reduced overall dimensions without losing its leakage control effectiveness

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention allows for parameter variations in step dimensions, recess sizes, and spacing between steps to optimize the seal for different machine sizes. This parametric flexibility enables the same basic design principle to be applied across different scales, from large to compact fluid machines

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS10281046B2Fluid machine having a labyrinth seal

Publication Date: 2019.05.07 DANFOSS AS

AI summary

The fluid machine includes a stationary member (6), a rotary member (5) and a labyrinth seal (9) including a succession of stationary steps (11) formed on the stationary member (6), and a succession of rotary steps (14) formed on the rotary member (5). The labyrinth seal (9) further includes a plurality of stationary recesses (18) each formed in a radial wall portion (12) of a respective stationary step (11), and a plurality of rotary recesses (21) each formed in a radial wall portion (16) of a respective rotary step (14). Each stationary step (11) defines a stationary projection (19) delimited by the stationary recess (18) formed on said stationary step (11), and each rotary step (14) defines a rotary projection (22) delimited by the rotary recess (21) formed on said rotary step (14). The axial width (Wr) of each of the stationary recesses (18) and of the rotary recesses (21) substantially equals the axial width (Wp) of each of the stationary projections (19) and of the rotary projections (22).