Boiler Spark Plug Fluid-Phase Fixing Material Assembly

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Solution Overview

Problem

Current spark plug assembly technologies for boilers face issues such as mechanical stress leading to ceramic sleeve breakage and micro-cracks due to different coupling methods, resulting in incomplete seals and reduced durability under thermal changes.

Innovation Solution

A spark plug design using a metallic main electrode, ceramic sleeve, and fixing plate with a unified application of a ceramic or glass fixing material in the fluid phase, which solidifies upon heating, ensuring all components are fixed using the same method, eliminating the need for subsequent thermal or mechanical treatments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If different coupling technologies are used for assembling spark plug components, then assembly flexibility is improved, but manufacturing complexity and reliability deteriorate due to multiple subsequent steps and inconsistent coupling methods

Engineering Contradiction:
Improveassembly flexibilityVSAvoidmanufacturing complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines multiple coupling operations into a single unified step by applying fluid-phase fixing material simultaneously to bond the ceramic sleeve to the fixing plate and to seal the gap between the ceramic body and housing hole. This eliminates the need for separate welding and sealing operations, reducing manufacturing complexity while maintaining assembly flexibility.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The fixing material serves multiple functions simultaneously: it acts as an adhesive to bond the ceramic sleeve to the fixing plate, as a sealant to prevent smoke leakage, and as a protective layer. This multi-functionality eliminates the need for separate coupling and sealing technologies, simplifying the manufacturing process.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Strength

If metallic rings are deformed to adhere to ceramic body and housing hole, then mechanical fixing is achieved, but ceramic sleeve breakage occurs due to pressure peaks from mechanical forces

Engineering Contradiction:
Improvemechanical fixing strengthVSAvoidceramic sleeve integrity
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent replaces the mechanical deformation method with a chemical bonding approach. Instead of deforming metallic rings to mechanically fix and seal the assembly, the invention uses fluid-phase fixing material that bonds the ceramic sleeve to the fixing plate and seals gaps through chemical adhesion, eliminating the pressure peaks that cause ceramic breakage.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention changes the state of the fixing material from solid (metallic rings) to fluid phase, allowing it to flow into and fill gaps uniformly without creating concentrated pressure peaks. The fluid material then solidifies to provide both mechanical strength and sealing, preserving ceramic integrity.

Inventive Principle:
Principle #35Parameter changes

3Strength

If glass material is heated to liquid phase and then solidified to couple components, then bonding is achieved, but micro-cracks form during manual bending, compromising seal reliability

Engineering Contradiction:
Improvebonding strengthVSAvoidseal quality
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The patent applies the fixing material in fluid phase before any bending or thermal processing occurs, allowing the material to fully penetrate and seal gaps. Subsequent bending and heating operations are performed after the material has already established the seal, preventing micro-crack formation that would compromise sealing quality.

Inventive Principle:
Principle #10Preliminary action

4Duration of action of moving object

If electrode is subjected to continuous thermal changes, then operational functionality is maintained, but micro-crack morphology changes lead to actual detachments of parts

Engineering Contradiction:
Improveoperational durationVSAvoidcomponent attachment reliability
Core Design Contradiction:
Duration of action of moving objectVSReliability

Solution Approach 1:

The invention uses a composite fixing material system that combines the properties of glass or ceramic materials with enhanced crack resistance. The material forms a flexible bond that can accommodate thermal expansion and contraction of the electrode during operation, preventing micro-crack propagation and component detachment while maintaining operational functionality.

Inventive Principle:
Principle #40Composite materials

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

This approach enhances the structural integrity and seal reliability of the spark plug by avoiding micro-cracks and pressure peaks, allowing for a more robust and efficient assembly process that is both functional and cost-effective.

Implementation Method 1

the fixing material is such that it can be applied in the fluid phase, so as to adhere to the connecting terminal, to the main electrode, to the sleeve and to the fixing plate, and subsequently solidified, for example through heating of the spark plug in an oven

Methodology Applied
Scientific EffectPhase change (fluid to solid through heating): Phase Change

Data Source

PatentEP3327352B1Detection/ignition spark plug for boilers and method for producing such a spark plug
Publication Date: 2021.05.19 POWER TECH SRL
  • EP3327352B1 patent drawingFigure 1~4
  • EP3327352B1 patent drawingFigure 5~6
  • EP3327352B1 patent drawingFigure 7~10

AI summary

A detection/ignition spark plug for boilers or the like, the spark plug comprising a filiform main electrode (2); a sleeve (5) for housing an intermediate portion of the main electrode (2); a fixing plate (4) provided with a lower surface configured for facing the combustion chamber of the boiler, an upper surface opposite to a combustion chamber, a housing hole (9) for the sleeve (5) so that a lower end of the main electrode (2) is inside the combustion chamber and an upper end of the main electrode is outside the combustion chamber; a connecting terminal (6) coupled to the upper end of the main electrode (2) in series with the sleeve (5); fixing material (8) between the connecting terminal (6) and the upper end of the main electrode (2), between the main electrode (2) and the sleeve (5) and between the sleeve (5) and the fixing plate (4); wherein the fixing material (8) is a material that, at first, is applied in the fluid phase so that it adheres to the connecting terminal (6), to the main electrode (2), to the sleeve (6) and to the fixing plate (4) and subsequently is brought to the solid phase.