Heating Cartridge with Localized Insulation Compaction for Control Element Integration

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Solution Overview

Problem

Existing electrical heating cartridges face challenges in integrating temperature-dependent switching and control elements close to the heating coil, leading to poor thermal connection, increased manufacturing costs, and limited temperature control precision, especially in high-density configurations.

Innovation Solution

The solution involves arranging electrical switching and control elements in lightly or non-compacted axial sections of the insulating filling and metal jacket, allowing for precise placement near the heating conductor, with the insulating material filling compacted only around the heating conductors to prevent damage and ensure optimal heat transfer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If temperature-dependent switching and control elements are integrated close to the heating coil, then temperature control precision is improved, but the insulating material must be less compacted in those areas, which complicates the manufacturing process

Engineering Contradiction:
Improvetemperature control precisionVSAvoidmanufacturing process complexity
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent applies local quality by creating zones with different compaction densities within the insulating material. Areas surrounding temperature-sensitive control elements have reduced compaction density to protect them during compression, while other areas maintain high compaction for optimal thermal efficiency. This localized variation in material properties enables precise temperature control without compromising manufacturing feasibility.

Inventive Principle:
Principle #3Local quality

2Loss of energy

If the insulating material is heavily compacted to improve thermal efficiency, then heat transfer is improved, but control elements become damaged due to compression forces

Engineering Contradiction:
Improvethermal efficiencyVSAvoidcontrol element integrity
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The patent implements local quality by varying the compaction density of the insulating material throughout the heating cartridge. Regions containing temperature-dependent control elements are intentionally left with lower compaction density to shield these components from damaging compression forces, while maintaining high compaction density in regions dedicated to optimal heat transfer, thus resolving the conflict between thermal efficiency and component protection.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent applies segmentation by dividing the insulating material into functionally distinct zones: protected zones with reduced compaction surrounding control elements, and high-performance zones with heavy compaction for thermal efficiency. This spatial segmentation allows each region to fulfill its specific function without compromising the other.

Inventive Principle:
Principle #1Segmentation

3Ease of manufacture

If control elements are placed in end areas of the heating cartridge, then assembly is simplified, but temperature fluctuations can only be detected in these end areas, limiting control precision

Engineering Contradiction:
Improveassembly simplicityVSAvoidtemperature detection coverage
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent transitions from one-dimensional temperature monitoring (limited to end areas) to three-dimensional coverage by embedding temperature-dependent control elements throughout the axial length of the heating cartridge. This spatial distribution in multiple positions along the heating element enables comprehensive temperature detection and control across the entire heating zone, not just at the ends.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

4Loss of energy

If the heating cartridge is highly compressed to increase density, then thermal efficiency is improved, but control elements cannot be integrated within the heating cartridge body

Engineering Contradiction:
Improvethermal efficiencyVSAvoidcontrol element integration flexibility
Core Design Contradiction:
Loss of energyVSAdaptability or versatility

Solution Approach 1:

The patent applies local quality by creating protected zones with reduced compaction density at specific locations within the heating cartridge where control elements are positioned. These localized low-density regions act as protective chambers that accommodate temperature-sensitive components while the surrounding and distant regions maintain high compaction for optimal thermal efficiency, enabling both high-density construction and control element integration.

Inventive Principle:
Principle #3Local quality

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 configuration enables precise temperature control, prevents overheating, and simplifies the manufacturing process by allowing the integration of control elements in various axial positions, while maintaining the structural integrity and thermal efficiency of the heating cartridge.

Implementation Method 1

heating conductor which is arranged in a metal jacket... made of steel or stainless steel and embedded in a compressed insulating material filling made of metal oxide

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

compressed insulating material filling made of metal oxide, in particular magnesium oxide... ensures optimal heat transfer

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP2180759B1Electric heating device
Publication Date: 2015.09.09 TUERK & HILLINGER GMBH & CO
  • EP2180759B1 patent drawingFigure 1~2
  • EP2180759B1 patent drawingFigure 3~4
  • EP2180759B1 patent drawingFigure 5~6

AI summary

The device has a wire-shaped heating conductor (7) embedded into a metal casing (2) made of steel or high-grade steel arranged in a compact insulation material filling (6) made from magnesium oxide. The conductor has electrical connectors (13, 14) guided away from the casing. The conductor is switched by two temperature-dependent activatable, electrical switching and control elements (9, 10). The switching and control elements are arranged axially opposite to multiple lightweight or uncompressed axial sections (4) of the insulation material filling and the metal casing.