Segmented Labyrinth Seal for Radially Moving Grate Shafts

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Sealing challenges in high temperature combustion environments, such as incinerators and boiler plants, arise due to dust deposition and encrustation on sealing elements, leading to impaired functionality and extensive labor for repair and replacement.

Innovation Solution

A labyrinth seal arrangement comprising overlapping first and second seal discs, each composed of angularly extending disc parts with interengaging projections and recesses, provides effective sealing while allowing shaft movement in a radial direction, facilitating easy disassembly and replacement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a seal is used to close the wall opening and prevent material escape and air infiltration, then sealing effectiveness is improved, but dust deposition and encrustation on sealing elements impede movement and cause breakage

Engineering Contradiction:

Improvesealing effectivenessVSAvoiddust deposition and encrustation

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The seal is divided into multiple disc-shaped sealing elements arranged in series along the shaft. Each disc can independently handle dust deposition without affecting the entire seal system, allowing partial replacement if needed while maintaining overall sealing effectiveness.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The sealing elements are designed to accommodate radial movement of the shaft while maintaining contact with the wall opening. The discs can move radially with the shaft but remain engaged with the wall, ensuring continuous sealing despite shaft displacement and dust accumulation.

Inventive Principle:

Principle #15Dynamics

2Reliability

If sealing elements are designed to withstand high temperature combustion environments and maintain sealing under shaft movement, then sealing reliability is improved, but repair and replacement require extensive labor and downtime

Engineering Contradiction:

Improvesealing reliability under thermal and mechanical stressVSAvoidlabor and downtime for repair and replacement

Core Design Contradiction:

ReliabilityVSEase of repair

Solution Approach 1:

The seal consists of multiple discrete disc elements that can be independently removed and replaced. If one disc becomes damaged or encrusted, only that specific disc needs replacement rather than the entire seal assembly, significantly reducing maintenance labor and downtime.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The disc-shaped sealing elements are nested in series along the shaft, with each disc fitting within the radial space of the others during shaft movement. This nested arrangement allows easy access to individual discs for maintenance while maintaining compact packaging during operation.

Inventive Principle:

Principle #7Nested doll (Nesting)

3Adaptability or versatility

If the shaft moves radially within the wall opening to operate combustion grate steps, then operational functionality is improved, but maintaining a effective seal during radial movement becomes more difficult

Engineering Contradiction:

Improveshaft radial movement capabilityVSAvoidsealing effectiveness during radial movement

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The sealing discs are designed to move radially with the shaft while maintaining continuous contact with the wall opening. The discs flex and position themselves to accommodate the shaft's radial displacement, ensuring the seal remains effective throughout the full range of motion required for combustion grate operation.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The seal transitions from a static linear arrangement to a three-dimensional nested configuration that accommodates radial movement. The discs are arranged in multiple radial layers that can expand and contract, allowing the seal to adapt to shaft movement in the radial dimension while maintaining sealing integrity.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Data Source

PatentUS12595851B2Labyrinth seal arrangement

Publication Date: 2026.04.07 MARTIN GMBH FUR UMWELT UND ENERGIETECHNIK

AI summary

An exemplary seal arrangement includes a labyrinth seal (1). The seal is in operative engagement with a shaft (2) that extends in an opening (3) in a wall (4) bounding a riddlings hopper (13). The exemplary shaft moves along at least one radial direction on an orbital or eccentric path within the wall opening so as to suitably cause movement of at least one grate step of a firing grate. First seal discs (5) extend radially relative to the shaft axis and are in fixed operative connection with the shaft. Second seal discs (6) also extend radially and are in fixed operative connection with a seal housing (8) that is attached to the wall. Throughout shaft movement within the opening, first seal discs continuously extend intermediate and in radially overlapping relation with second seal discs, and second seal discs continuously extend intermediate and in radially overlapping relation with first seal discs. At least one of the seal discs is comprised of a plurality of assembled angularly extending disc parts (15, 16) to facilitate removal and replacement.