Heating Element Coil Spacer for Thermal Expansion

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Solution Overview

Problem

Existing support structures for coiled heating elements fail to maintain collinearity, concentricity, and centering during thermal expansion, leading to uneven temperature distribution and reduced element life due to stress-induced deformation and gravity-induced misalignment.

Innovation Solution

A spacer system with interlocking columns around the circumference of the coil, allowing for radial movement within a channel to accommodate expansion while maintaining collinearity and centering, and featuring mating components to ensure concentricity and guide the coil's position.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If slots are provided in ceramic spacers to allow expansion and contraction, then the heating element can accommodate thermal expansion, but collinearity and concentricity of the coils cannot be maintained

Engineering Contradiction:
Improvethermal expansion accommodationVSAvoidcollinearity and concentricity
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent introduces an intermediary mechanism (the spacer assembly with protrusions and recesses) that mediates between the heating element's need to expand and the requirement to maintain precision. The protrusions engage with recesses in a way that permits radial expansion while constraining lateral movement, thus maintaining collinearity and concentricity during thermal cycling.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The spacer assembly is designed with dynamic characteristics, allowing it to move radially inward and outward to accommodate thermal expansion while maintaining its function of preserving collinearity and concentricity. This dynamic design enables the system to adapt to changing thermal conditions without compromising structural precision.

Inventive Principle:
Principle #15Dynamics

2Stability of the object's composition

If protrusions are attached to heating element coils to block them from passing through spacers, then material accumulation in lower parts is mitigated, but temperature uniformity deteriorates and failure risk increases

Engineering Contradiction:
Improvematerial distribution uniformityVSAvoidtemperature uniformity and failure risk
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

Instead of attaching protrusions to the heating element coils (the traditional approach), the patent inverts the approach by providing protrusions on the spacers themselves. This reversal allows the spacers to actively engage with and support the coils, preventing material accumulation while maintaining temperature uniformity and reducing failure risk.

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

3Device complexity

If no constraining mechanism is provided, then the assembly is simple, but coil deformation worsens over time leading to decreased element life

Engineering Contradiction:
Improveassembly simplicityVSAvoidelement life
Core Design Contradiction:
Device complexityVSDuration of action of stationary object

Solution Approach 1:

The spacer assembly is designed to be self-aligning through its protrusion-recess engagement mechanism. The gravity-induced downward force on the coil turns causes the spacers to automatically engage with the coils, providing continuous support and preventing deformation without requiring external active control or complex adjustment mechanisms.

Inventive Principle:
Principle #25Self-service

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 spacer system allows the coil to expand and contract freely while maintaining collinearity, concentricity, and centering, reducing stress-induced deformation and ensuring uniform temperature distribution and extended element life.

Implementation Method 1

maintains one or more of the collinearity, concentricity and centering of the heating element coil during thermal expansion of the heating element

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

the vertical support column moves slideably within the vertical channel, and wherein an increase in a length of the heating element coil upon heating is accommodated by a radially outward movement of the spacers

Methodology Applied
Scientific EffectThermal expansion and contraction: Thermal Expansion

Data Source

PatentEP2400815B1Support structure for heating element coil
Publication Date: 2017.05.17 KANTHAL THERMAL PROCESS INC
  • EP2400815B1 patent drawingFigure 1A~1B
  • EP2400815B1 patent drawingFigure 2~3
  • EP2400815B1 patent drawingFigure 4~5

AI summary

Spacer for a vertical support structure of a heating element coil includes a mating feature including complimentary components on first opposing sides of the spacer, a cavity, open to second opposing sides of the spacer, and an extension, offset from an axis intersecting the mating features, the extension including a pocket sized to fit an individual loop of the heating element coil. The spacer can be incorporated into a support structure for a heating element coil interlocking adjacent loops of the coil so that they are retained in a collinear and concentric arrangement while allowing the loops of the coil to move freely inward and outward from the central axis in unison.