Spring-Actuated Stoker Furnace Sealing Device

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Solution Overview

Problem

Conventional stoker type incinerators face issues with sealing performance due to rotational movement of metal seals, which can lead to air leakage and abnormal combustion when foreign matter gets caught between the metal seal and the movable fire grate.

Innovation Solution

A sealing device with a spring-actuated front fire grate that restricts movement, combined with a shaft-like member and moving direction restricting portion, minimizes the movement of the front fire grate and improves contact with the movable fire grate, thereby enhancing sealing performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the metal seal is allowed to rotate about a pin to follow movement of the movable fire grate, then the seal can adapt to the movement, but the rotational movement adversely affects the sealing performance

Engineering Contradiction:
Improveadaptability to movementVSAvoidsealing performance
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

Instead of allowing the seal to rotate freely to adapt to movement, the invention inverts the approach by restricting rotation and instead allowing limited linear movement. The seal is constrained to move only in the direction of the movable fire grate's movement, preventing rotational adverse effects while maintaining sealing contact through controlled linear displacement.

Inventive Principle:
Principle #13The other way round (Inversion)

2Adaptability or versatility

If the metal seal is permitted to move freely, then it can follow the movable fire grate movement, but foreign matter can be caught between the seal and grate, leading to abnormal combustion

Engineering Contradiction:
Improvemovement following capabilityVSAvoidforeign matter entrapment
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The invention segments the movement freedom by introducing a guide structure that divides the movement into allowed and restricted components. The seal can move linearly to follow the grate but is prevented from rotating or moving laterally, which would cause foreign matter entrapment. This segmentation of movement degrees maintains adaptability while eliminating harmful effects.

Inventive Principle:
Principle #1Segmentation

3Reliability

If the front fire grate is restricted in movement by the support portion, then sealing performance is maintained, but the grate cannot fully follow the movable fire grate movement

Engineering Contradiction:
Improvesealing performanceVSAvoidmovement following capability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The invention applies dynamics by making the seal's movement characteristics adaptable to the operating conditions. The guide structure allows the seal to dynamically adjust its position within constrained boundaries, following the movable fire grate's movement while maintaining optimal sealing contact. This dynamic constraint system balances following capability with sealing performance.

Inventive Principle:
Principle #15Dynamics

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 suppresses the movement of the front fire grate, maintaining optimal sealing performance and preventing air leakage, even when foreign matter is present, thus preventing abnormal combustion.

Implementation Method 1

a force of pulling the front fire gate in a direction opposite to the moving direction of the movable fire grate due to the spring acts on the front fire grate

Methodology Applied
Scientific EffectSpring force: Spring

Data Source

PatentEP3734155B1Stoker-furnace sealing device and stoker furnace
Publication Date: 2023.12.20 MITSUBISHI HEAVY IND ENVIRONMENTAL & CHEM ENG CO LTD
  • EP3734155B1 patent drawingFigure 1
  • EP3734155B1 patent drawingFigure 2
  • EP3734155B1 patent drawingFigure 3

AI summary

Provided is a sealing device in a stoker type incinerator, for sealing a gap between a drop wall (27) of the stoker type incinerator and a movable fire grate (16), the stoker type incinerator being provided with a plurality of fixed fire grates and a plurality of the movable fire grates (16), and in which objects to be incinerated are subjected to incineration while conveying the objects to be incinerated, the sealing device includes: a front fire grate (31) disposed so that a distal end (31c) of the front fire grate (31) abuts on the movable fire grate (16); a support portion (32) having a top surface support plate (33) fixed to the drop wall (27) to support a top surface (31a) of the front fire grate (31) and a bottom surface support plate (34) disposed below the top surface support plate (33) to support a bottom surface (31b) of the front fire grate (31); and a spring (35) configured to urge the front fire grate (31) in a direction opposite to a direction in which the front fire grate (31) is moved with the movable fire grate (16).